EMISSIONS

Contents

Introduction ;: 3

Chapter 1-Regulating Emissions 6 A. What Emissions Are Regulated? 6 1. Hydrocarbons (HC) · 6 2. Carbon Monoxide (CO) 6

3. Oxides of Nitrogen (NOx ) 6 4. Particulates (PM) 6 B. How Emissions Are Produced 6 1. Formation of Hydrocarbons (HC) 7 a. Evaporative Emissions 7 b. Crankcase Emissions 7 c. Engine Exhaust 7 2. Formation of Carbon Monoxide (CO) 7

3. Formation of Oxides of Nitrogen (NOx ) 8 C. How Emissions Are Controlled 8 1. Pre-catalytic Converter Technology (Prior to the Early 1970s) 8 2. Post-catalytic Converter, Pre-electronic Feedback Control Technology (Mid-1970s to Early 1980s) 10 3. Post-catalytic Converter, Post-electronic Feedback Control Technology (Early 1980s to Present) 10 a. Catalytic Converter 10 b. Air Injection Reaction (AIR) 12 c. Exhaust Gas Recirculation (EGR) System 12 D. How Emissions Relate to Air Pollution 13

Chapter 2-Purpose of Inspection/Maintenance (I/M) 15 A. First 11M Tests 15 B. Enhanced 11M Requirements 16

Chapter 3-I/M Tests & Procedures 17 A. Pre-inspection Safety Check 17 B. Emissions Component Inspection 17 C. Clean-Screen Testing 17 1. Remote Sensing Devices (RSD) 18 2. Computer Generated Low-emitting Vehicle Profiles 18 3. Vehicle Model Year Exemptions 18

VEHICLE INSPECTION HANDBOOK SET /1999 .. CONTENTS EMISSIONS

D. Basic 11M Tests 18 1. Idle Inspection Test 18 2. Two-speed Idle Test 18 E. Enhanced 11M Tests 19 1. 1M 240 Test 19 a. 1M 240 Test Procedure 19 b. 1M 240 Emissions Measurements 20 2. BAR-31 Test 20 3. ASM Test 21

Chapter 4-Evaporative System Inspection 22

Chapter 5-0n-Board Diagnostic System 23

Chapter 6-Diesel Smoke Emissions Inspection 24 A. Diesel Engine Technology 24 B. Federal Emissions Standards 24 C. Strategies To Improve Diesel Engine Emissions 24 1. Engine Modifications 24 2. Exhaust After-treatment 24 D. Heavy-duty Diesel Vehicle (HDDV) Opacity (Smoke) Tests 25 1. Snap Acceleration Test 25 2. Rolling Acceleration Test 25

Glossary 26

Acronyms 28

IJI VEHICLE INSPECTION HANDBOOK SET f 1999 EMISSIONS

Introduction

The American Association of Motor Vehicle can reduce emissions to the level expected for a Administrators (AAMVA) in partnership with properly maintained vehicle. the Canadian Council of Motor Transport The agency responsible for the 11M program Administrators (CCMTA) is proud to offer this in each area may elect to employ one of the section of the new, expanded version of the tests described herein or a variation of the test. Vehicle Inspection Handbook Set, with recom­ These agencies also establish emissions test pro­ mended inspection procedures and standards cedures and standards. For this reason, this for all types of vehicles in the United States and handbook specifically excludes emissions Canada including: passlfail criteria. Specific questions about test­ ing programs in any jurisdiction should be • Motorcycles, directed to the appropriate local agency. • Passenger Vehicles & Light Trucks, • Salvage Vehicles, • Trucks, Buses & Trailers, and Based on the Development of • Emissions. Emissions Programs in the U.S.

Each handbook section contains information Information in this handbook is based primari­ compiled from multiple sources and is based on lyon the development of emissions inspection actual working systems and programs in the programs, related technology and legislation in United States and Canada. the United States. Implementation of 11M pro­ To order additional handbook sections, grams is mandatory in those areas of the coun­ please use the order form provided with this try that are not in compliance with the handbook or contact AAMVA (703-522-4200). National Ambient Air Quality Standards In Canada, contact CCMTA (613-736-1003). (NAAQS), under provisions of the 1977 Clean Air Act. These areas are commonly referred to as "nonattainment areas." Emissions Inspections In the United States, the Environmental Protection Agency (EPA) is the federal agency The Emissions Inspection Handbook provides responsible for regulating vehicle emissions, general background information on emissions and the state of New Jersey was the first to use Inspection and Maintenance (11M) programs, its regulatory authority to require that an 11M with an overview of the emissions test strate­ program be established. By 1983, 11M pro­ gies used by many jurisdictions. It also grams were established in 64 cities throughout describes the emissions control equipment the United States. installed by vehicle manufacturers. 11M was identified in the early 1970s as an effective way to reduce in-use motor vehicle emissions. By repairing their vehicles and per­ forming routine maintenance, vehicle owners

VEHICLE INSPECTION HANDBOOK SET / 1999 II INTRODUCTION EMISSIONS

Canadian Programs 1971 to 1979. When the United States adopted stricter standards in 1980 and 1981, Canada Unlike the United States, Canada does not have did not. Canadian standards remained the same a national mandate for provinces to implement until September 1, 1987. 11M programs. Instead, the Canadian Council Because of different approaches to air pollu­ of Ministers of the Environment (CCME) tion control, Canadian vehicles from the 1975 serves as an intergovernmental forum for dis­ to 1988 period have different control equip­ cussion and joint action on environmental ment compared to their American counterparts. issues, and makes recommendations about Among these differences are the later use of where 11M programs should be implemented. catalytic converters in Canadian vehicles. The CCME also publishes federal guidelines for During the 1981-1987 period, certain manufac­ 11M programs that provide a standard format turers produced vehicles only to the United for the future development of 11M programs in States EPA standards. However, many of the Canada. major manufacturers produced different ver­ Currently, Canada has one active 11M pro­ sions of the same model vehicle-one that gram (AirCare) in lower mainland British would comply with the 1981 United States Columbia, which began in 1992. In addition, standards and another version with less sophis­ Ontario plans to implement annual emissions ticated emissions control systems that complied testing for cars, trucks and buses in certain with Canadian standards. Often, popular mod­ urban areas. Canada also has a voluntary els that were capable of meeting only Canadian nationwide emissions inspection clinic program emissions standards were sold without a cat­ designed to inform vehicle owners about the alytic converter or with a simpler oxidation importance of proper vehicle maintenance and catalyst. A similar vehicle made to meet United to capture emissions information on Canada's States standards would have been equipped in-use light duty vehicle fleet. with a three-way catalyst and possibly an air pump. u.s. and Canadian Differences in Emissions Standards for Reviewed by Experts New Vehicles This handbook was developed by AAMVA's In 1954, cloud chamber work by California Handbook Working Group, which is part of researcher Dr. Hagan-Smit established the first AAMVA's Engineering and Vehicle Inspection connection between vehicle exhaust and smog. Committee. Information was provided and/or Since then, the United States and Canadian reviewed by representatives from CCMTA, governments have set standards for vehicle American Automobile Manufacturers emissions to bring down the levels of pollu­ Association, Association of International tants, and the automobile industry has Automobile Manufacturers, Inc. and Specialty responded by developing new emissions control Equipment Market Association. technologies. The source of statistics used in this hand­ Beginning in 1971, new cars had to meet book is the 1996 American Automobile evaporative emissions standards established by Manufacturer's Association Facts and Figures. the United States and Canada for the first time. It is important to note that Canadian and United States' emissions standards for new vehicles were similar, but not identical from

II VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS INTRODUCTION

Handbook Set Reflects oping this expanded edition of the handbook to Experience and Cooperation provide inspection recommendations for all types of vehicles. AAMVA has been involved in publishing vehi­ In 1997, CCMTA offered its manual, cle inspection handbooks since the late 1980s, Commercial Vehicle Inspections in Canada, as when AAMVA and the National Highway the basis of the Trucks, Buses & Trailers Traffic Safety Administration began working Inspection Handbook, and AAMVA and cooperatively to publish handbooks for passen­ CCMTA agreed to collaborate on the publica­ ger vehicles, trucks and buses with information tion of the entire handbook set. provided primarily by the American Because it includes recommendations for Automobile Manufacturer's Association. both the United States and Canada, the Vehicle In 1995, AAMVA published the first edition Inspection Handbook Set is an important step of the Vehicle Inspection Handbook for passen­ toward the harmonization of standards ger vehicles. A year later, AAMVA's Engineering throughout North America. and Vehicle Inspection Committee began devel­

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 1

Regulating Emissions

A. What Emissions Are and pressure causes oxygen and nitrogen to Regulated? chemically bond. The greater the tempera­ ture/pressure during combustion, the more Internal combustion engines used in most of oxides of nitrogen will be formed. In the today's vehicles are a significant source of man­ United States, approximately 32 percent of made air pollution. These engines produce four man-made oxides of nitrogen are produced types of emissions that can be regulated by motor vehicles. through emissions inspection and maintenance (I/M) programs: 4. PARTICULATES (PM) • Hydrocarbons (He), Man-made particulate emissions are micro­ • Carbon Monoxide (CO), scopic solid particles that are small enough

• Oxides of Nitrogen (NOx ) and to remain suspended in the air. They are pro­ • Particulates (PM). duced primarily by industrial processes and internal combustion engines. The United 1. HYDROCARBONS (HC) States Environmental Protection Agency (EPA) regulates particulate emissions at 2.5 Hydrocarbons are emitted either as and 10 microns. unburned fuel in the exhaust or as fuel vapor from the engine or fuel system. This is known as evaporative emissions. B. How Emissions Are Produced Automobiles, trucks, and motorcycles con­ tribute approximately 27 percent of the man­ Once ignited in the cylinder of an internal com­ made hydrocarbons emitted into the earth's bustion engine, the hydrogen and carbon con­ atmosphere worldwide. tained in the fuel react with oxygen in the air as they burn. This reaction produces the energy that drives down the pistons in an internal 2. CARBON MONOXIDE (CO) combustion engine. It also creates chemical Carbon monoxide is a product of incomplete byproducts that are emitted in the exhaust. combustion caused by an overly rich airlfuel Ideally, the combustion of fuel (He) and air ratio. This may be caused by an excess of should produce only water (H20) and carbon fuel or a shortage of air delivered to the dioxide (C02), The nitrogen component of air engine cylinders. In the United States, passes through the reaction unchanged in the approximately 80 percent of man-made car­ form of N2. However, fuel is not composed of bon monoxide is from motor vehicles. In pure hydrocarbons (He), and internal combus­ urban areas, vehicles may account for as tion engines do not produce perfect combus­ much as 90 percent of the carbon monoxide. tion. As a result, in addition to carbon dioxide (C02) water (H20) and nitrogen (N2), motor vehicle exhaust also contains carbon monoxide 3. OXIDES OF NITROGEN (NOx ) (CO), oxides of nitrogen (NOx )' hydrocarbons Oxides of nitrogen are formed in the engine's (He), and particulates. combustion chamber when high temperature

VEHICLE INSPECTION HANDBOOK SET / 1999 EMISSIONS CHAPTER 1: REGULATING EMISSIONS

1. FORMATION OF HYDROCARBONS (HC) Fuel Evaporation­ Hydrocarbon emissions may be released Tank & Carburetor 20% through evaporative emissions (fuel evapora­ tion), crankcase emissions and engine exhaust.

a. Evaporative Emissions Evaporative emissions result from the release of fuel vapors from the fuel system simply due to leakage caused by the expansion of vapors. This type of emission causes the Exhaust most concern in warm climates and during 60% the summer months. As ambient tempera­ tures rise, vapor pressure in a vehicle's fuel Three Sources of Auto Emissions system increases because fuel in the fuel tank evaporates and expands. If uncontrolled, this higher vapor pressure is vented to the atmos­ 2. FORMATION OF CARBON MONOXIDE (CO) phere causing the release of evaporative Carbon monoxide emissions are produced emISSiOns. during the combustion process when the In addition, fuel vapors are emitted when airlfuel ratio is too rich. An ideal (stoichio­ motor vehicles are refueled. Vapor recovery metric) air/fuel ratio for gasoline is 14.7 lbs. controls, referred to as Stage I and Stage II, of dry air to 1 lb. of gasoline. When convert­ are installed at most gasoline pumps in areas ed to gallons of air and gasoline, this equates that do not meet United States air quality to 9,000 gallons of air to one gallon of gaso­ standards. line. Evaporative emissions also may be pro­ Anything that causes a rich air/fuel mix­ duced when vehicle exhaust pipes, engines or ture such as a clogged air filter or air intake other heat sources, warm the surface of the passage, fuel-contaminated oil, a leak in the road. air intake system, or a faulty fuel control b. Crankcase Emissions system component, such as an oxygen sensor or mass air flow sensor, will cause tailpipe The second source of hydrocarbon emissions emissions of carbon monoxide to increase. is the engine crankcase. Exhaust gases from Carbon monoxide emissions also increase the combustion chamber leak past the piston when an engine is under strong load, such as rings into the crankcase. If uncontrolled, during heavy acceleration or while climbing blow-by gases would be exhausted to the atmosphere. Over time, the volume of blow­ a steep grade. Fuel enrichment under these by gas increases as piston rings and cylinder conditions is necessary to protect the engine and catalyst from overheating. walls begin to wear, allowing more gas to leak into the crankcase during compression.

c. Engine Exhaust The third source of hydrocarbon emissions is the engine exhaust. Due to incomplete com­ bustion, not all of the hydrocarbon in motor vehicle fuel is burned during combustion.

VEHICLE INSPECTION HANDBOOK SET {1999 II CHAPTER 1: REGULATING EMISSIONS EMISSIONS

3. FORMATION OF OXIDES OF trol devices to be used, but instead sets perfor­ NITROGEN (NOx) mance standards. This allows vehicle manufac­ Oxides of nitrogen emissions result from turers to choose the best available technology incomplete combustion under very high to meet their engineering needs and stimulates temperature and pressure conditions. In fact, innovation. if the combustion reaction were allowed to The technology used to control vehicle emis­ continue for a longer period of time, the sions can be divided into three generations: oxides of nitrogen (NOJ formed during • Pre-catalytic Converter Technology combustion would again reduce to nitrogen (Nz) and carbon dioxide (COz) and/or water • Post-catalytic Converter, Pre-electronic (HzO). However, rotation of the crankshaft Feedback Control Technology automatically purges the exhaust gases from • Post-catalytic Converter, Post-electronic the cylinder, terminating the Feedback Control Technology combustion reaction and fixing the oxides of nitrogen compounds in the exhaust. The majority of the vehicles currently on the It should be noted that there is a natural roads in the United States fall into the third trade-off between reducing oxides of nitro­ generation. gen emissions and reducing carbon monox­ ide, and to a lesser extent, hydrocarbon 1. PRE-CATALYTIC CONVERTER TECHNOLOGY emissions. This trade-off occurs because the (PRIOR TO THE EARLY 1970s) operating conditions that are conducive to the formation of oxides of nitrogen suppress Emission reductions during the late 1960s carbon monoxide and hydrocarbon emis­ and the early 1970s were obtained primarily sions, and those engine operating conditions through improved engine design. Carburetors that are conducive to carbon monoxide and were designed to deliver a leaner air/fuel hydrocarbon emissions suppress the forma­ mixture to the cylinders, ignition timing was tion of oxides of nitrogen. Engine calibration retarded to extend the combustion reaction engineers must optimize this trade-off when allowing for more complete burning of the designing the software that controls the fuel, and compression ratios were reduced to airlfuel ratio under all operating conditions. 8.5 to 1 or less. Thermostatically controlled Finally, exhaust after-treatment methods air cleaner systems also were developed to are relied upon to lower levels of all three improve cold start driveability, which was emissions. This is accomplished by catalyzing adversely affected by leaner air/fuel mixture. chemical reactions that transform some In addition to base engine design changes, harmful gases into less harmful gases. several emissions control systems were added to vehicles during this period. Carbon canis­ ter systems were added to vehicles in order C. How Emissions Are to control evaporative emissions by storing excess vapor while the vehicle was at rest, Controlled and the vapor was redirected to the intake In the United States, the 1990 Clean Air Act manifold when the vehicle was operating. gave the EPA broad authority to regulate motor Modified camshafts were installed along vehicle emissions, as well as other industrial with exhaust gas recirculation systems to sources of pollutants. Vehicles built for sale in help reduce oxides of nitrogen emissions. the United States must meet tailpipe and evapo­ Positive Crankcase Ventilation (PCV) sys­ rative emissions standards for hydrocarbons, tems, which vented the crankcase to the carbon monoxide, oxides of nitrogen and par­ intake manifold rather than to the atmos­ ticulates, as determined by Congress. The EPA phere, also were introduced. generally does not mandate the pollution con­ -:-r------­ -=- VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 1: REGULATING EMISSIONS

CONVEI\lTIOI\lAL OXIDATION CATALYST (COC) • Controls HC and CO • Also known as two-way catalyst Substrate Is Ceramic Honeycomb Material Coated with Catalyst Material ® Gas Contains HC-CO

Gas Flow from Engine __ S=~:'::i~-·::%'I~l k :E==:::::...... Enters Ahead of Catalyst Shell Assembly Contains Supports and Substrate

THREE-WAY CATALYST (TWC) CONVERTER • Controls HC. CO and NOx • Contains a COC element and a three-way element • Also called dual-bed converter Mixing Chamber .~@) Outlet to Muffler

G) Exhaust Gas Contains

H~\~ Conventional Catalyst Oxidizes HC-CO

"Downstream" Air Enters ®"Upstream" Air Enters Mid-Bed Air Port Three-way Catalyst Oxidizes with Exhaust ... or HC-CO and Reduces NOx

Diagrams of Early Control Systems

VEHICLE INSPECTION HANDBOOK SET /1999 II CHAPTER 1: REGULATING EMISSIONS EMISSIONS

2. POST-CATALYTIC CONVERTER, soned the catalytic converters by depositing PRE-ELECTRONIC FEEDBACK on the catalytic surface, thereby preventing CONTROL TECHNOLOGY the oxidation reaction needed to convert (MID-1970s TO EARLY 1980s) hydrocarbon and carbon monoxide to car­ In the mid-1970s, EPA emissions standards bon dioxide and water. This, in addition to were tightened significantly. The need for the fact that there was increasing evidence large reductions in hydrocarbon and carbon that lead contamination from gasoline was monoxide emissions prompted the introduc­ having serious adverse health effects, especial­ tion of oxidation catalytic converters. These ly for young children, hastened the mandato­ catalytic converters chemically convert ry introduction of unleaded gasoline and the hydrocarbon (He) and carbon monoxide phasing out of lead as a fuel additive. (CO) exhausted from the engine into water Development of the catalytic converter (H20) and carbon dioxide (C02 ) before the also resulted in the development of air injec­ exhaust gas leaves the tailpipe. tion systems. To operate properly, a catalytic Prior to the introduction of catalytic con­ converter requires oxygen and heat. While verters, lead was widely used by fuel refiners the hot exhaust gases flowing through the to boost the octane of gasoline. But lead poi­ catalyst naturally supply the heat, air injec­ tion systems had to be introduced to supply the requisite air. o o c Air injection systems were either pump- or CD !:2." pulse-based, depending on whether the air s­ o was supplied by a belt-driven pump, or by o OJ air ingestion through a valve body operating Q. o on the negative pressure pulse in the exhaust CATALYTIC manifold caused by valve closing. Air was CONVERTER routed from the pump or valve body to the SYSTEM catalytic converter. Some systems also fur­ nished air to the exhaust manifold near the exhaust valves in order to take advantage of the extremely high temperature in this region to extend the combustion process in the exhaust manifold.

3. POST-CATALYTIC CONVERTER, SINGLE EXHAUST SYSTEM WITH POST-ELECTRONIC FEEDBACK CATALYTIC CONVERTER CONTROL TECHNOLOGY (EARLY 1980s TO PRESENT)

Exhaust Emissions standards were tightened again Pipe beginning with the 1981 model year. Not only were hydrocarbon and carbon monox­ ide standards stricter, but a drastic reduction in oxides of nitrogen was required as well. As a result, catalytic converter technology was further refined to control all three of Catalytic Converter the regulated emissions.

Oxidation Catalytic Converter Operation a. Catalytic Converter The purpose of the automotive catalytic con­ verter is to chemically convert emissions of

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 1: REGULATING EMISSIONS

hydrocarbons, carbon monoxide and oxides of nitrogen into less harmful byproducts. This is accom­ THREE·WAY PLUS OXIDATION plished by coating a substrate mate­ rial that has a very large amount of surface area with catalytic metals NOHC c> (platinum, palladium, and rhodium CO are the most commonly used) in order to provide a sufficient num­ ber of catalytic sites for oxidation and reduction of the targeted emis­ sions through catalyzation.

During the catalyzation process, (NO) Nitrous Oxide Nitrogen (N2) hydrocarbon and carbon monoxide (CO) Carbon Monoxide Water (H20) (HC) Hydrocarbons Carbon Dioxide (C0 ) molecules are oxidized, and oxides 2 of nitrogen are reduced. While oxi­ dation of hydrocarbon and carbon monoxide requires oxygen, oxides COLD ENGINE of nitrogen are most efficiently reduced when there is an oxygen Bypass Diverter Check Valve deficiency. Valve r.====0!I1lJ===:::::;] To catalyze emissions, the con­ verter must be heated to approxi­ mately 250 degrees Celsius (482 degrees Fahrenheit). Beyond approximately 850 degrees Celsius (1562 degrees Fahrenheit), thermal Check Valve Bypass 04 04 04 04 -+ 04 degradation of the catalyst begins Diverter to become critical. Prolonged oper­ Valve ation at such high temperatures will Exhaust eventually destroy the catalytic Manifold Catalytic Converter activity.

HOT ENGINE Catalysts are manufactured in dif­ ferent sizes and use three different types of catalyst support materials Operation of Three-way Catalyst-Air/Fuel Ratio or substrate: • Ceramic pellet (bead type-not several things are done to help get the converter up widely used) to this temperature quickly (also known as "light­ • Ceramic monolith (honeycomb off") to reduce cold-start emissions. The idle speed type) may be raised; air may be injected into the exhaust • Metal monolith (honeycomb manifold; a small "light-off" catalyst may be posi­ type) tioned close to the exhaust manifold; or the main catalyst itself may be located closer to the exhaust Because a catalytic converter is manifold. inefficient until it reaches a temper­ In order for a three-way catalytic converter to ature of approximately 250 degrees effectively reduce all three pollutants, the engine Celsius (482 degrees Fahrenheit), must be operated at or near an air/fuel ratio of 14.7

VEHICLE INSPECTION HANDBOOK SET /1999 m CHAPTER 1: REGULATING EMISSIONS EMISSIONS

to 1 (stoichiometric), and an electronically feeling for the air pulses in the outlet hoses controlled fuel system is necessary. In addi­ from the valve. The proper operation of elec­ tion to a control computer, called the power­ tronically controlled systems can be checked train control module (PCM), such a system through the vehicle's On-Board Diagnostic requires various actuators that regulate idle (OBD) system using an appropriate scan tool air, purge, or Exhaust Gas Recirculation or key-activated code storage retrieval. (EGR) flow, for example, and numerous sen­ sors to monitor the state of the engine. The c. Exhaust Gas Recirculation (EGR) Systems sensors may monitor conditions such as The purpose of an EGR system is to lower exhaust gas oxygen content, manifold the temperature of combustion in order to absolute pressure, crankshaft angular posi­ suppress the formation of oxides of nitrogen tion and speed, inlet air temperature, coolant emissions. This is accomplished by reintro­ temperature, and throttle position. These ducing inert exhaust gases to the combustion inputs are "fed back" (hence the term "feed­ chamber during the power stroke. The inert back" control system) to the computer, gases mix with the reactive air fuel mixture, which determines the appropriate amount of thereby diluting the charge, and in turn, low­ fuel, spark advance, EGR flow, purge, etc., ering the peak temperature of combustion. to provide under given operating conditions. There are two types of EGR systems­ vacuum-driven and electronic. b. Air Injection Reaction (AIR) The AIR system is one of the earlier emissions Vacuum-driven EGR systems typically con­ control systems introduced by manufacturers. sist of a pintle-type, diaphragm-actuated Because of the system's relative cost-effective­ valve located on the exhaust manifold, that ness, it is still in widespread use today. is controlled by a backpressure transducer AIR systems are designed to pump air into coupled with an EGR solenoid. The back­ the exhaust manifold and to the downstream pressure transducer modulates EGR flow bed of a dual-bed catalytic converter. Under according to a ported vacuum signal. cold engine/catalyst operating temperatures, Electronic EGR systems typically consist of oxygen in the air allows unburned fuel in the one or more EGR solenoids acting on a pin­ exhaust to continue to burn in the exhaust tle valve to allow more or less EGR flow to manifold and outlet pipe. That, in turn, the intake manifold, depending upon engine reduces the amount of unburned fuel that operation conditions and loads. The sole­ enters the catalyst before it has warmed up noid(s) are controlled by the powertrain con­ and increases the temperature of the exhaust trol module (PCM), which "maps" EGR and gases entering the cold catalyst, which has­ other engine control functions according to tens light-off. After the engine and catalyst software protocols designed by the manufac­ reach normal operating temperatures, air is turer. Electronic EGR can be more precisely diverted downstream to the catalyst oxida­ controlled, and therefore is less likely to tion bed, where the oxygen in the air again cause driveability problems, unless it is mal­ facilitates the conversion of hydrocarbons functioning. Also, because electronic EGR (HC) and carbon monoxide (CO) to water operates independently of manifold or port­ (H20) and carbon dioxide (C02), ed vacuum, EGR flow can occur over a There are three general types of AIR sys­ greater range of operation regimes, thereby tems used by manufacturers-air pump-based enhancing the system's oxides of nitrogen systems, aspirated systems and pulse air feed­ reduction function. er systems. AIR systems should be checked The EGR system should be inspected for for proper condition and routing of vacuum proper condition and routing of vacuum and air delivery hoses. In most systems, hoses. The condition of the valve and free switching valve function can be verified by operation of the pintle also should be veri­ m VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 1: REGULATING EMISSIONS

fied. The proper functioning of electronic oxides of nitrogen is the internal combustion EGR systems can be verified through the engine found in motor vehicles. OBD software using an appropriate scan tool or key-activated code storage retrieval. The primary component of photochemical smog is ozone. Ozone is made up of three atoms of oxygen (03), Ozone occurs naturally D. How Emissions Relate to in the upper atmosphere and serves to block Air Pollution out harmful ultraviolet rays from reaching the earth's surface. However, near the earth's sur­ Emissions playa significant role in creating the face, ozone formed from man-made pollutants air pollution problem commonly referred to as has been shown to exacerbate certain lung con­ smog, a term which was formed originally by ditions, such as asthma, and to accelerate the combining the words smoke and fog. There are deterioration of rubber, as well as certain paints two types of smog-sulfurous smog and photo­ and coatings. chemical smog. Ozone levels are generally highest during summer months and in warmer climates for Sulfurous smog results from a combination of two reasons. First, there are more hours of day­ sulfur-bearing pollutants emitted by coal- and light during the summer. Second, summertime oil-burning stationary sources. Mobile sources, meteorological conditions produce stagnant such as on-road vehicles, also contribute to sul­ masses of high pressure air over large parts of furous smog. North America. These stagnant conditions Photochemical smog is caused to a great extent allow hydrocarbons and oxides of nitrogen to by motor vehicles. Photochemical smog results mix for long periods of time, often several from hydrocarbons and oxides of nitrogen days, which results in elevated ozone levels and reacting chemically in the presence of sunlight. the possibility of multiple violations of national One of the main sources of hydrocarbons and air pollution standards.

OZONE FORMATION Volatile Organics (VOC) + Oxides of nitrogen (NOx) = OZONE

NOx&VOC NOx&VOC

NOx&VOC

Cars FaCtories Refineriesl Power Plants Chemical Plants

VEHICLE INSPECTION HANDBOOK SET / 1999 III CHAPTER 1: REGULATING EMISSIONS EMISSIONS

The effect of photochemical smog is multi­ exists around an inversion, the dispersion rate plied when temperature inversions occur and of the pollutants is slowed even more. This is where geographical barriers exist. An inversion why certain locations, such as the Los Angeles is when the air temperature at higher elevations basin, have a very serious smog problem, while is warm relative to surface air temperature. The other locations with a similar number of people warmer air effectively traps the colder air, pre­ and automobiles, may not. venting dispersion. When a mountain range

m VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 2

Purpose of Inspection/Maintenance (11M)

The purpose of 11M programs is to identify A. First 11M Tests through inspection, vehicles that are emitting significantly more pollutants than they were Although the United States Environmental designed to emit, and to bring them back into Protection Agency (EPA), the federal agency compliance with applicable standards through responsible for regulating vehicle emissions, maintenance and repair services. eventually promulgated regulations covering 11M was identified in the early 1970s as an five different "short tests," two of which were effective way to reduce in-use motor vehicle loaded mode tests, the vast majority of jurisdic­ emissions. By repairing their vehicles and per­ tions implemented 11M programs based on a forming routine maintenance, vehicle owners two-speed idle test in order to keep the 11M test can reduce emissions to the level expected for a simple and inexpensive, usually under $20. properly maintained vehicle. The state of New These 11M tests could be performed at either Jersey was the first to use its regulatory author­ centralized or decentralized facilities. Central­ ity to require that an 11M program be estab­ ized facilities are operated by either govern­ lished. ments or contractors working for governments. In the United States, in 1977, the Clean Air Decentralized facilities are privately owned Act was amended to require, among other mea­ repair facilities, gas stations or franchised sures, mandatory implementation of 11M pro­ dealerships. grams in those areas of the country that were EPA auditing of 11M programs found that not in compliance with the National Ambient reductions in emissions were substantially less Air Quality Standards (NAAQS). These areas than expected. In addition, newer, computer­ are commonly referred to as "nonattainment controlled cars and trucks required more areas." If states with responsibility for those sophisticated test procedures. The 1990 Clean areas did not implement 11M programs, they Air Act sought to address these issues by creat­ faced federal sanctions including the loss of ing a category of 11M called "enhanced 11M." highway funds and the ability to grant permits Enhanced 11M programs were required to be for new industrial sources. implemented in all nonattainment areas classi­ fied as serious, severe or extreme, based on the degree and duration of noncompliance with NAAQS.

VEHICLE INSPECTION HANDBOOK SET /1999 CHAPTER 2: PURPOSE OF INSPECTION/MAINTENANCE EMISSIONS

B. Enhanced 11M Requirements In 1995, the United States Congress passed an amendment to the National Highway Systems In 1992, EPA established requirements for Designation Act that allowed jurisdictions sub­ enhanced 11M programs. The purpose of stantial flexibility in designing an 11M program enhanced 11M tests is to produce greater reduc­ that would still be considered "enhanced." In tions in hydrocarbon, carbon monoxide and response, jurisdictions have developed a variety oxides of nitrogen emissions than can be of 11M programs based on different test proto­ achieved with basic 11M tests. Strategies used to cols. The majority of these programs are decen­ get these additional reductions include: tralized. The following sections detail some of • Evaporative system tests, the different types of 11M test protocols that • Road simulation tests for oxides of nitrogen may be used. For program requirements that tailpipe emissions, pertain to specific areas, check with the 11M operating agency in that jurisdiction. • $450 waiver repair requirements, and • More stringent program enforcement.

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 3

11M Tests & Procedures

A. Pre-inspection Safety vehicle should be performed. Vehicles that Check appear to be overheated and those that are leaking coolant or oil should be rejected from To prevent injury and/or damage to vehicles, it testing. is important to conduct a safety inspection before performing a dynamometer-based JIM emissions test. Refer to appropriate sections of B. Emissions Component the Passenger Vehicles & Light Trucks Inspection Handbook for more information Inspection about inspection procedures. At a minimum, A visual inspection should be conducted for the the following items should be checked before presence and condition of the following com­ proceeding with the emissions inspection. ponents. If any emissions components are miss­ ing, the vehicle should be rejected. Tires. Reject the vehicle if a tire is excessively worn or a space-saver spare is used on a drive Fuel Inlet Restrictor-To prevent the introduc­ axle. The risk of a blowout should not be tion of leaded fuel into a vehicle manufactured taken. for unleaded fuel use. Brakes. If the vehicle cannot maintain the drive trace during the test due to poor braking per­ Catalytic Converter-The presence of the cat­ formance, it will fail the test. alytic converter is required to be verified as part of the anti-tampering inspection. Exhaust System Leaks. A visual inspection of the entire exhaust system should be performed Under-the-hood Emissions Control Compo­ prior to an JIM test. Vehicles with leaking nents-Some jurisdictions require visual inspec­ exhaust systems should be rejected. tion for the presence of the EGR system, air Steering and Suspension. If steering or suspen­ pump, PCV, etc. sion components are significantly worn or damaged, or have been modified to the extent that normal function is affected, the vehicle C. Clean-Screen Testing should be rejected. Because the majority of vehicles normally pro­ Fuel System. Vehicles that are leaking fuel duce emissions well below JIM standards, the should be rejected because they are a fire haz­ United States EPA allows 11M programs to ard. exempt certain "clean" vehicles from complete 11M tests. Jurisdictions may use one of three OverheatingIFluid Leaks. A visual inspection of different approaches for clean-screening: the instrument panel malfunction indicator remote sensing devices (RSD), computer gener­ lights or gauges, as well as a visual inspection ated low-emitting vehicle profiles, or vehicle of the cooling system and underbody of the model year exemptions.

VEHICLE INSPECTION HANDBOOK SET /1999 CHAPTER 3: 11M TESTS & PROCEDURES EMISSIONS

By using one of these clean-screen tests, juris­ rpm while the vehicle is in "PARK" or "NEU­ dictions will be able to reduce the number of TRAL." vehicles going through either test-only or test­ During the test, the exhaust gas analyzers and-repair liM systems. EPA and jurisdiction's use Non-Dispersive Infrared (NDIR) technolo­ liM agencies will jointly determine the effec­ gy to measure the gases. Hydrocarbon is mea­ tiveness of liM programs with clean-screen sured in parts per million (ppm) and carbon components. monoxide in percent (%). Exhaust gas analyzers are usually built to 1. REMOTE SENSING DEVICES (RSD) specifications developed by the California Bureau of Automotive Repair (BAR). BAR Remote sensing devices can be used for on­ specifications are labeled by the year they road inspections or at inspection stations to became effective. There are BAR-74, BAR-80, measure the emissions of vehicles in opera­ BAR-84, BAR-90, and BAR-97 specifications, tion. If vehicles scheduled for liM tests meet which reflect changes due to more stringent the jurisdiction's "clean-screen" standards, standards that were imposed on motor vehicles they may be exempted from the liM test cur­ over this time period, as well as the increased rently scheduled. use of computer technology. Jurisdictions set emissions standards based 2. COMPUTER GENERATED LOW-EMITTING on the national emissions certification stan­ VEHICLE PROFILES dards to which the vehicle was built to comply. Compared to older vehicles, newer cars have California has developed computer profiles much stricter emissions standards. of the vehicles that are statistically most probable to pass liM tests. These computer profiles are based on previous liM results, 1. IDLE INSPECTION TEST vehicle specific studies and remote sensing The idle inspection test measures exhaust device data. By using these profiles, jurisdic­ emissions with the vehicle in "NEUTRAL" tions may issue liM test exemptions for the (manual transmission) or "PARK" (automat­ current liM tests. ic) and the engine at idle speed. When the vehicle is properly prepared for the test, and 3. VEHICLE MODEL YEAR EXEMPTIONS the exhaust gas analyzer is warmed up and calibrated, the test can be performed. EPA and state testing has shown that most of With the analyzer in the test mode, the the vehicles currently being sold in the inspector places a probe in the tailpipe and United States are able to meet liM standards observes the emissions measurement reading, for up to four years, provided scheduled or waits for electronic "pass" or "fail" maintenance is performed. Therefore, juris­ results. The exhaust emissions must fall dictions may exempt new vehicles for up to below the applicable standard in order to four years from liM tests. pass the inspection.

D. Basic 11M Tests 2. TWO-SPEED IDLE TEST During this test, emissions measurements are Basic liM test programs are used in areas with made at two speeds while the vehicle is in moderate air pollution problems. Basic tests use "PARK" or "NEUTRAL." exhaust gas analyzers to check the exhaust con­ First, the vehicle emissions are measured centration of two pollutants, hydrocarbon and at idle. Then, the engine is accelerated and carbon monoxide. The test may be conducted held at approximately 2,500 rpm for a speci- while the vehicle is at idle speed or at 2,500

III VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 3: 11M TESTS & PROCEDURES

fied time period while the emissions are mea­ different than a transient liM test where the sured again. A third reading is taken when exhaust gas is measured all the time. Because of the engine is returned to idle speed. the less demanding testing procedure, a CVS The pass/fail determination may be based system does not have to be used with a steady­ on the lowest of the two emissions readings state test. Instead, an idle-test emissions analyz­ taken at idle speed. Alternatively, depending er with the addition of an oxides of nitrogen on applicable jurisdictional regulations, all testing module may be used. three readings may be required to be below Jurisdictions use different test procedures for the applicable emissions standards. their steady-state enhanced liM tests. The most By allowing the second set of idle readings common is the Acceleration Simulation Mode to be used for making the pass/fail determi­ (ASM). nation, jurisdictions are recognizing the pos­ sibility that the vehicle may not have been 1. 1M 240 TEST properly preconditioned for the emissions test. Running the vehicle at 2500 rpm helps 1M 240 stands for Inspection/Maintenance, to ensure that the engine and catalytic con­ 240-second inertia-loaded dynamometer test. verter are operating at a normal temperature. This enhanced test measures mass emissions Catalytic converter cooling that can occur in grams per mile through a tailpipe exhaust under prolonged idle conditions may other­ test while the vehicle is driven on a variable wise cause a properly functioning vehicle to inertia-loaded dynamometer. The test fail the test. includes vehicle speed transitions from 0 to 56 mph (0 to 90 kmh), and emissions are measured through a CVS system. The maxi­ E. Enhanced 11M Tests mum test time is 240 seconds, unless precon­ ditioning provisions allow for an extension. There are two types of enhanced liM tests used The 1M 240 test is derived from various to simulate on-the-road operating conditions: parts of the Federal Test Procedures (FTP). transient tests and steady-state tests. The FTP is a much lengthier dynamometer­ Transient tests measure tailpipe exhaust at based emissions test protocol, which uses varying speeds. This is done by placing a vehi­ more sophisticated measurement equipment cle on a dynamometer (essentially a treadmill) and exhaust gas analyzers to which new and running it through a drive cycle that repre­ vehicles are certified by the United States sents normal operating conditions. Jurisdictions EPA. New vehicles must meet applicable EPA use different driving cycles for their transient or California Air Resources Board (CARB) enhanced liM tests including the IM-240 and emissions standards before they may be the BAR-31. All the exhaust coming out of the offered for sale in the United States. tailpipe is collected and measured in a testing device called a Constant Volume Sampling a. 1M 240 Test Procedure (CVS) system. Mter the safety pre-inspection, the vehicle's Steady-state tests measure the tailpipe registration is compared to the vehicle identi­ exhaust at one, two or three constant speeds. fication number (YIN) plate and the YIN is This is done by placing a vehicle on a entered into the test lane computer. The dynamometer, running it up to the target speed, computer identifies and sets the appropriate and measuring the exhaust gas at only the tar­ dynamometer inertia load (flywheel weights get speed for a specified period of time. If more that closely simulate the acceleration weight than one target speed is used, the vehicle is of the vehicle) and vehicle emissions stan­ brought up to those speeds and exhaust gas is dards, or cutpoints that determine pass or measured only at those speeds as well. This is fail.

VEHICLE INSPECTION HANDBOOK SET / '999 CHAPTER 3: 11M TESTS & PROCEDURES EMISSIONS

The vehicle is then safety-locked to the Note: An important difference between the dynamometer rollers, and an inspector "dri­ 1M 240 and the basic 11M program is the ves" the vehicle on the dynamometer follow­ way emissions are measured. 1M 240 looks ing a "drive trace" that is displayed on a at the total mass of exhaust emissions from monitor. The inspector must keep the vehicle the vehicle (grams of pollutants per mile) by speed within several mph of the drive trace using a CVS system. Mass emissions tests displayed on the screen. If the speed goes out provide a much clearer picture of the total of the required range, the test will be aborted amount each vehicle contributes to air pollu­ and must be restarted. (See the drive trace tion. In comparison, basic and ASM-based diagram below.) enhanced programs measure the concentra­ tion of pollutants in the exhaust (percent or b. 1M 240 Emission Measurements parts per million). A vehicle will fail the 1M 240 test if it exceeds the grams per mile (gpm) standard by the end 2. BAR-31 TEST of the test, or it may fail if it does not meet the "fast pass" criteria established by the EPA. The BAR-31 test is similar to the 1M 240 If a jurisdiction uses the "fast pass" criteria, test. The same test equipment is used and the vehicle will pass the test if the mass emis­ exhaust emissions are measured the same sions do not exceed a lower threshold than way. The BAR-31 test is faster than the 1M the actual standard within a prescribed period 240 test. It can be conducted in 31 seconds, of time. Emissions standards for 1M 240 tests and because of the simpler driving trace, the are set by jurisdictions based on EPA guide­ BAR-31 test is easier to perform. lines.

60 57.5 ­ 55 ­ 52.5 . 50· 47.5 . 45· 42.5 . 40· :g, 37.5 ­ E 35­ - 32.5' -g 30' 8. 27.5 . (J) 25· 22.5 . 20· 17.5 . 15 ­ 12.5 ­ 10 ­ 7.5 ­ 5 ­ 2.5 . o L...L.+--+--+--+--+-+-+-+-+-+--t-''''I--l--l--l--l--+--+--+--+--+-+-+-+-+--+-+--+-+---'' o 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 8 24 40 56 72 88 104 120 136 152 168 184 200 216 232 Time (seconds)

Enhanced 11M Driving Cycles-1M 240

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 3: 11M TESTS & PROCEDURES

Usually, at least three BAR-31 tests are ation load during the federal test procedures conducted before a passlfail decision is cycle. The ASM 2525 tests the vehicle at 25 made. (See the BAR-31 diagram below.) mph (40 kmh) at 25 percent of the same load. 3. ASM TEST The ASM tester is also known as the ASM stands for Acceleration Simulation BAR-97 analyzer. Hydrocarbons, carbon Mode. The ASM is a steady state, rather monoxide and oxides of nitrogen are sam­ than a transient, loaded mode test. During pled by the same type of tailpipe probe used an ASM test, emissions are measured at a for idle liM tests. Emissions results are

constant speed/load setting while the vehicle recorded as HC (ppm), NOx (ppm) and CO is driven on a dynamometer. This is different percentage. from the 1M 240 and the BAR-31 tests The ASM procedure has become the most where the emissions are tested at all speeds utilized of all the Enhanced liM tests. States of the test cycle. As the name implies, this including California, Connecticut, Georgia, test simulates an acceleration load and mea­ Ohio and Virginia have implemented ASM sures associated emissions. programs. The Canadian province of There are two common ASM tests. The Ontario also is using the ASM test in their ASM 5015 tests the vehicle at 15 mph (24 liM program. kmh) at 50 percent of the maximum acceler­

60 57.5 ­ 55 ­ 52.5 ­ 50· 47.5 . 45· 42.5 . 40 - i 373~: - 32.5' ] 30· ~27.5 . en 25­ 22.5 . 20· 17.5 . 15 . 12.5 - 10 . 7.5 ­ 5 ­ 2.5 . o o 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 8 24 40 56 72 88 104 120 136 152 168 184 200 216 232 lime (seconds)

Enhanced 11M Driving Cycles-Bar-31

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 4

Evaporative System Inspection

The United States Environmental Protection Agency (EPA) and various jurisdictions are in the process of redefining evaporative system inspections. A description of these new tests will be published in future revisions of this handbook.

Evaporative system inspections are designed to check for poor seals in the vehicle's gas cap and evaporative system. During the test, which is part of the IIM inspection program, the inspector checks the vehicle's gas cap with a pressurized tester to detect leakage. If the gas cap doesn't hold pressure beyond a certain tolerance, then the owner must replace the gas cap. A visual inspection of the evaporative system also may be required. Although the cost of replacing a gas cap is relatively inexpensive, the benefits for air quality are significant, according to EPA modeling. It also should mean increased fuel economy for the motorist.

VEHICLE INSPECTION HANDBOOK SET / 1999 EMISSIONS CHAPTER 5

On-Board Diagnostic System (OBO)

The United States Environmental Protection OBD II in California, were required by the Agency (EPA) and various jurisdictions are in California Air Resources Board (CARB) and the process of redefining On-Board Diagnostic were fully implemented by the 1996 model 11M inspections. A description of these new year. EPA implemented similar enhanced OBD tests will be published in future revisions of this requirements in 1996. Enhanced OBD systems handbook. require functional checks of emissions-related components/systems in addition to the electrical Early diagnostic provisions, known as OBD I, continuity monitoring required by OBD I. required the electronic control module (ECM) These functional checks are required for misfire to monitor emissions-related electrical and elec­ detection, the catalyst system, the evaporative tronic components, including itself, for circuit system, the fuel system, the oxygen sensor, the continuity and operation within design volt­ transmission, and any other component that age/amperage tolerances. If a malfunction was could affect emissions. detected, the system alerted the driver by illu­ For vehicles equipped with enhanced OBD minating a malfunction indicator light on the systems, a simple check indicates that the vehi­ dashboard labeled "CHECK ENGINE" or cle emissions control system is in good working "SERVICE ENGINE SOON," and a fault code order. With the key turned to "ON," but in the corresponding to the component or system in pre-start position, the inspector can verify that question was stored in the ECM memory for the "CHECK ENGINE" light or malfunction retrieval by a service technician. indicator light is working and that the malfunc­ Beginning with the 1994 model year, so­ tion indicator light turns off shortly after start­ called "enhanced" OBD systems, known as ing the engine.

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS CHAPTER 6

Diesel Smoke Emissions Inspection

A. Diesel Engine Technology B. Federal Emissions Diesel engines are unthrottled as opposed to Standards gasoline-fueled engines. In effect, they are con­ In 1970, the u.s. EPA established standards for stantly operating with a "wide-open" throttle. acceleration and lug-down smoke opacity for Power is varied by controlling the amount of heavy-duty diesel engines, with an additional fuel injected into the combustion chamber or standard for peak smoke in 1973. Standards pre-chamber, and the airlfuel ratio varies in for particulate emissions were established with accordance with power requirements. In com­ increasing stringency for model years 1988, parison, in a gasoline engine, the air/fuel ratio 1991 and 1994. is tightly controlled around stoichiometry, about 14.7/1. Typically, a diesel engine operates very lean of stoichiometry, which accounts in Strategies to Improve part for its relatively better fuel economy and c. lower hydrocarbon and carbon monoxide emis­ Diesel Engine Emissions sions. On the other hand, the compression-ignition 1. ENGINE MODIFICATIONS process using injected liquid fuel leads to the production of smoke. This smoke is comprised Diesel engine manufacturers responded to of unburned carbon particles that have other EPA particulate standards principally by associated absorbed compounds such as sul­ employing electronic fuel controls, increasing fates and heavy hydrocarbons. Turbocharger injection pressure, using non-linear fuel­ diesel engines are especially susceptible to tran­ injection strategies, and changing combus­ sient smoke production because of an inherent tion chamber shapes. EPA also required lag between a rapidly increased fuel delivery petroleum refineries to reduce the amount of and a turbocharger's ability to respond with sulfur in diesel fuels that lowered sulfate additional air. Consequently, delay devices are emlSSlons. installed on diesel fuel pumps to momentarily limit maximum fuel injection until the tur­ 2. EXHAUST AFTER-TREATMENT bocharger has spooled up to deliver sufficient Strategies have been examined to reduce par­ air. If these delay devices, called "puff-lim­ ticulate emissions downstream of the engine iters," are maladjusted or tampered with, a exhaust ports by using particulate traps and diesel engine will produce a momentary burst oxidation catalysts. Particulate traps literally of black smoke due to transient over-fueling trap particles in a metallic mesh or ceramic when it is accelerated from a stop or when the substrate where the accumulated soot is sub­ gears are shifted. sequently burned off. In engines with low particulate emissions, further reduction can

VEHICLE INSPECTION HANDBOOK SET {1999 EMISSIONS CHAPTER 6: DIESEL SMOKE EMISSIONS INSPECTION

be effected by employing oxidation catalysts 1. SNAP ACCELERATION TEST to burn off absorbed hydrocarbons, which The vehicle transmission is placed in neutral comprise a large portion by weight of partic­ and all brakes on the tractor and trailer are ulate matter from newer engines. released. The wheels are chocked for safety, and the smoke test equipment is placed in or on the exhaust stack depending on the type D. Heavy-duty Diesel Vehicle of smoke meter used. (HDDV) Opacity (Smoke) The driver is instructed to quickly press Tests the accelerator pedal to the floor and hold it until the signal to release is given. This is There are two basic types of tests that may be done a minimum of five times. If the pedal is performed in a roadside environment on heavy­ not depressed quickly upon instruction to do duty diesel vehicles: the Snap Acceleration Test so, the test may not be accurate and will and the Rolling Acceleration Test. These tests need to be repeated. may be performed to quantify the smoke emis­ sions in either a static location or over a short 2. ROLLING ACCELERATION TEST distance in a parking lot or roadside. At least three snap accelerations are conducted prior to The test equipment is attached to the each official test to purge the exhaust system of exhaust stack, and the test operator sits in loose soot and to stabilize the emissions. Some the cab of the truck. The brakes are released. states have adopted variations of these proce­ Then, the transmission is placed in first gear dures in order to accommodate the conditions with the clutch engaged to bring the vehicle under which the tests are performed. This to a slow roll. When the operator signals, the handbook seeks to describe the basics of the driver must accelerate rapidly, as if merging most popular heavy-duty diesel vehicle smoke into traffic. The truck is driven approximate­ emissions test procedures. ly 25 feet under these conditions, and the opacity or smoke is measured. Note: Some test equipment is more suitable than others for this test.

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS

Glossary

Air/Fuel Ratio. The number of pounds of air in Dynamometer. A stationary device on which a combination with one pound of fuel provided vehicle may be operated with the drive wheels by the fuel system of an engine, expressed as a rotating to simulate road conditions (load). It is numeric ratio, for example, 14.7(air):1 (fuel). used to simulate actual vehicle driving.

Ambient Air. The air surrounding a prescribed Environmental Protection Agency (EPA). The object or region, such as a vehicle or a metro­ United States agency, established by the passage politan area. of the original Clean Air Act in 1970, which is responsible for establishing and administering Analyzer Calibration. The feeding of several programs aimed at controlling environmental calibration gases through an analyzer in order degradation, subject to the requirements and to set the response of the analyzer. limitations imposed on it by the United States Congress, as expressed in the Clean Air Act. Centralized Testing. Emissions testing per­ EPA regulates sources of air and water pollu­ formed by a state or regional government or by tion, solid waste disposal, pesticide use, envi­ a contractor hired by a state or regional gov­ ronmental radiation and hazardous substances. ernment. Federal Test Procedure (FTP). A multi-mode, Clean Air Act (CAA). An Act of Congress, mass emissions test that utilizes the constant which has been amended several times since it volume sampling system. The vehicle is started was originally passed in 1970. IIM provisions after remaining at an ambient temperature of were included in the 1977 and 1990 amend­ 60 to 86 degrees Fahrenheit (15.5 to 30 degrees ments. Celsius) for 12 hours. The vehicle is then oper­ ated on a dynamometer through simulated Constant Volume Sampling (CVS). An emis­ urban and highway driving cycles. The mass sions sampling method in which the total emissions are measured during the test. exhaust volume of a vehicle is analyzed for the presence of certain chemical compounds, Gross Emitter. A vehicle whose in-use emissions including regulated emissions. levels are substantially higher than applicable emissions pass/fail levels. Cutpoint. The maximum allowable emission level that can be emitted from a motor vehicle Inversion. A climate condition in which an air for a particular pollutant, for a given test. Also mass above the ground is at a warmer tempera­ called "standard." ture than the air mass at ground level.

Decentralized Testing. Conducted at privately Loaded Mode Test. An emissions measurement owned testing facilities, usually licensed by the procedure used for sampling tailpipe emissions jurisdiction. Most decentralized testing facilities while subjecting the vehicle's engine to simulat­ are equipped to perform both testing and ser­ ed road conditions using a chassis dynamome­ vicing of motor vehicles. ter.

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS GLOSSARY

National Ambient Air Quality Standards Steady State Testing. A test in which the vehicle (NAAQS). The maximum allowable amount of is maintained at a constant RPM throughout specific pollutants in the ambient air for a pre­ the test. scribed geographical region. Standards have been established for carbon monoxide, ozone, Stoichiometry. An airlfuel ratio for gasoline of hydrocarbons, nitrogen oxides, sulfur oxides, 14.7:1, which, under ideal conditions, results in and particulates. There are two types of ambi­ perfect combustion. It is relative to this airlfuel ent air standards - the primary standards ratio that "lean" and "-rich" are defined. apply to human health, and the secondary stan­ dards apply to material damage. Stringency Factor. A measure (in percent) used to indicate the anticipated portion of the vehi­ Non-attainment Area. A geographic area classi­ cle population whose emissions would exceed fied by the EPA as having a moderate, serious, the specified cutpoints for hydrocarbon, carbon severe, or extreme air pollution problem, as monoxide and/or nitrogen oxides. This is the measured in terms of the degree to which the portion of the vehicle population that would region exceeds National Ambient Air Quality initially fail the inspection. Functionally, it is Standards (NAAQS). synonymous with failure rate.

Ozone. A photochemical oxidant that results Tampering. The intentional removal, discon­ from a reaction of hydrocarbon and nitrogen nection, misadjustment or rendering inopera­ oxides in the presence of sunlight. Ozone is the tive of any required emissions control device or primary ingredient in smog. system on a motor vehicle.

Pre-conditioning. Operation of a vehicle prior Test Report. The enhanced VM printed report to testing for the purpose of stabilizing engine given to the driver of a vehicle upon comple­ and catalyst temperatures in order to obtain tion of a test. exhaust emissions readings that are more accu­ rate. Transient Test. A test conducted on a dynamometer "loaded" to simulate various on­ Purge. The process of drawing fuel vapor from road operating conditions. the evaporative emissions canister and reintro­ ducing the vapor to the combustion process Vehicle Emissions Control Information Label. during normal vehicle operation. A label located in the engine compartment of a vehicle that provides specific emissions control Quenching. The effect of combustion chamber information to aid inspectors and repair techni­ surface cooling of the mixture temperature to a CIans. point below that of combustion. Waiver. A waiver-of-repair that allows the vehi­ Short Test. Anyone of several emissions tests cle to continue to be used, even though it does that are less complicated and less time-consum­ not pass the emissions standards. ing and/or costly than the FTP, and that are .specified by federal regulation for purposes of determining warranty liability.

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS

Acronyms

AIR Air Injection Reaction liM Inspection and Maintenance

ASM Acceleration Simulation Mode kmh Kilometers per hour

BAR (California) Bureau of Automotive 0 Oxygen Repair OBD On-Board Diagnostics CAA Clean Air Act OBDI On-Board Diagnostics- CARB California Air Resources Board First Generation

CCME Canadian Council of Ministers of the OBDII On-Board Diagnostics- Environment Second Generation

CO Carbon Monoxide mph Miles Per Hour

CO2 Carbon Dioxide N2 Nitrogen

CVS Constant Volume Sampling NDIR Non-Dispersive Infrared

ECM Electronic Control Module NOx Oxides of Nitrogen (x = 1 or 2)

EGR Exhaust Gas Recirculation System PCM Power Control Module

EPA Environmental Protection Agency PCV Positive Crankcase Ventilation

FTP Federal Test Procedure PM Particulate Matter gpm Grams Per Mile ppm Parts Per Million gm/mi RSD Remote Sensing Devices HC Hydrocarbon

H 2O Water

VEHICLE INSPECTION HANDBOOK SET /1999 EMISSIONS

About the Publishers

American Association of Motor Canadian Council of Motor Vehicle Administrators Transport Administrators Founded in 1933, AAMVA is a nonprofit, edu­ Established by the provincial, territorial and cational organization representing state and federal governments, CCMTA is a nonprofit provincial motor vehicle and law enforcement organization that promotes understanding and agencies throughout the United States and cooperation in all matters concerning the Canada. administration, regulation and control of motor AAMVA's programs encourage uniformity vehicle transportation and safety in Canada. and reciprocity among the states and provinces, CCMTA reports to the Council of Ministers and promote liaison activities with other levels Responsible for Transportation and Highway of government and the private sector. AAMVA Safety and is responsible for motor vehicle reg­ also stresses highway safety through its involve­ istration, driver licensing, road safety pro­ ment in numerous national coalitions, and its grams, motor carrier regulatory issues, compli­ program and research activities provide guide­ ance activities for commercial vehicles and dri­ lines for more effective public service. vers, and other transportation projects and Association members include all United agreements. States and Canadian jurisdictions plus Members include senior representatives American Samoa, Guam, Puerto Rico and the from all of the provincial and territorial Virgin Islands. AAMVA associate members governments, as well as representatives from include organizations, associations and business the federal government. Private industry orga­ enterprises with interests compatible with nizations and other government agencies in AAMVA and its program objectives. Canada and the United States participate as associate members.

©1999 American Association of Motor Vehicle Administrators. All rights reserved.

VEHICLE INSPECTION HANDBOOK SET /1999

American Association of Motor Vehicle Administrators 4301 Wilson Blvd., Suite 400, Arlington, VA 22203 703-522-4200 www.aamva.org

CCJ~11A· CCA1)1I Canadian Council ofMotor Transport Administrators 2323 St Laurent Blvd., Ottawa, Ontario KIG 4J8 613-736-1003 www.ccmta.ca