DEPARTMENT OF ELECTRONICS & INSTRUMENTATION ENGINEERING

Arockia Vijay Joseph, Assistant Professor(OG), SRM University, [email protected] EI1109 - AUTOTRONIX UNIT - III SPARK IGNITION ENGINE MANAGEMENT Includes • Requirements • Components • Principle of Operation • In Detail about Types of Ignition System • Fault Diagnosing Requirements • • design • Air-fuel ratio • Engine Speed range • Engine load • Combustion Air and fuel temperature mixture • Emission regulations CONTACT BREAKER IGNITION SYSTEM COMPONENTS & PRINCIPLE OF OPERATION Components Primary Circuit Ignition switch

Distributor and Ballast resistor Condenser Battery

Ignition coil Contact breaker Secondary Circuit cap

Rotor arm Spark plugs

Ignition coil Secondary + terminal terminal Battery

- terminal Spark Soft iron plug gap Casing core Primary windings Primary winding Secondar Secondary y winding windings

Insulator 300 Insulation turns 18000 Laminated paper turns iron core Contacts BACK EMF = 200V Types of Ignition coil Distributo r cap

Rotor arm

Condenser Cam

Base Contact plate breaker

Distributo r body Drive gear Centre contact End contact

Coil HT terminal Spark plug HT terminal

Securing lug

Spring loaded contact

Brass contact Distributor Operation

To coil primary Cam Centre Contacts terminal

Shaf t

Ga p Outer terminal Rotor arm

15 of 15 Silicone jacket Spark plug end

Termina l Contacts Rubber boot

Condenser Distributor end

Erosion - no condenser Termina l

Insulato Hex r

Ballast Coi resistor l

Meta l Gasket shell Thread Centre electrode

Side Gap electrode Use of Condenser ELECTRONIC IGNITION SYSTEM Why replace the Contact Breaker? • Accuracy limits. • Emission limits • Current flow in primary circuit is only 4A • Weaker mixtures need more energy from spark. Electronic Distributor IS

Distributor cap

Ignition switch

Coil

Spark plug

Speed sensor ICM Types of Sensors Involved • Optical Type • Induction Type • Hall IC Type Photo-coupler O/P of Photo-coupler Advantages

• Greater Sensitivity • Wide Dynamic Range • Free from EMI • Both Point and Distributed Range Induction Type Hall Effect Type Triggering Device

• Hall Effect Type • Inductive or Magnetic Pick up coil Type • Optical Type Along with the triggering device we have an ignition module which switches ON and OFF the spark plug based on the signal from the triggering device. Hall Effect Type Induction Type or Magnetic Pick up coil Optical Sensor Construction Optical sensor

Timing disc with slots Operation

Simple timing disc or rotor plate Receiver Volts

Transmitter

Time

Transmitter Ignition Module Types of Ignition System Programmed Ignition System What is it?

• Requirements are programmed in ECU’s memory. • ROM data are obtained through rigorous testing on engine dynamometer. • Term coined by ROVER • FORD, BOSCH and some more named as “Electronic Spark Advance” Advantages

• Ignition timing is accurate to the requirements. • Control inputs like engine speed, engine load, coolant temperature and knocking effect. • Starting improved • Fuel efficiency • So emissions are reduced. • Wearing components reduced. Schematic Diagram Thermistor (-90 to 180˚C) • A thermistor is a temperature-sensing element composed of sintered semiconductor material which exhibits a large change in resistance proportional to a small change in temperature. • It is made up of ceramic or polymer materials. Engine Coolant Temperature Sensor

1 ECT sensor 2 PCM 3 CPU Diaphragm Manifold Air Pressure Sensor Vapor Deposit

O/P Characteristics Position Sensor/ Inductive Type Engine Speed Sensor Crank Shaft Position Piston Position Sensor

Characteristics of Hall Effect Sensor Piezoelectric Knock Sensor Characteristics of Knock Sensor

From ECU • For Primary Circuit The primary winding current is been controlled by a heavy duty transistor.

Switch On ---- Ignition Timing Switch Off ---- Dwell period

• Secondary Circuit – similar to previous Distributorless Ignition System Schematic Diagram Direct Ignition System UNIT - IV COMPRESSION IGNITION ENGINE MANAGEMENT CARBURETTED SYSTEM History and Development

 Invented by Karl Benz in the year 1885 and was patented in 1886.  It was further developed by Hungarian Engineers.  In1900 carbureted system became an important step forward in Automotive engineering.  Until late 1980s carbureted system were the usual fuel delivery method used. Parts of a Carburetted System

.  Fuel lines/Pipes.  .  .  .  .

What is a Carburetor?

A device that blends air and fuel for an IC engine for combustion. A device that atomizes and vaporizes the fuel for purpose of combustion. A carburetor mixes the air and fuel in a particular ratio, which is accurately 14.7:1. The ratio can be changed by the usage of its parts namely a choke. It works on Bernoulli's principle,ie,the faster air moves, the lower its static pressure, and the higher its dynamic pressure. Types of Air-Fuel mixtures

 Normal – 14.7:1 (Blue flame)

 Rich – 10 to 12:1 (Yellow flame)

 Lean-Air units greater than 15.(Whitish-blue). Factors to be considered for the mixture:  Ambient temperatures  Atmospheric pressures  Engine speeds and loads  Centrifugal forces namely cold/hot start, idling/slow running, acceleration and high power at full . Circuits (Parts of a Carburetor)

 Open pipe called “Barrel”.  Air horns.  Venturi.  Float Chamber.  Float.  Mixture needle.  Throttle valve.  Choke valve.

Operation A carburetor basically consists of an open pipe, a "throat" or "barrel" through which the air passes into the of the engine. The pipe is in the form of a venturi: it narrows in section and then widens again, causing the airflow to increase in speed in the narrowest part.  Below the venturi is a butterfly valve called the throttle valve — a rotating disc that can be turned end-on to the airflow, so as to hardly restrict the flow at all, or can be rotated so that it (almost) completely blocks the flow of air. Contd.. This valve controls the flow of air through the carburetor throat and thus the quantity of air/fuel mixture the system will deliver, thereby regulating engine power and speed. Fuel is introduced into the air stream through small holes at the narrowest part of the venturi.  Fuel flow in response to a particular pressure drop in the venturi is adjusted by means of precisely-calibrated orifices, referred to as jets, in the fuel path.

Barrel

 Barrel is cylinderical pipe like structure through which the air flows half the way and the rest air-fuel mixture.  Types: a)Single Barrel b)Multiple Barrel.  Multiple barrels are used to accommodate the higher flow rate with large .

High performance 4 barrel carburetor Venturi Types of Venturies  FIXED VENTURI: . Here the fuel flow is altered by varying the air-velocity in the venturi. . It is used in down draft corburetors.  VARIABLE VENTURI: . Here the fuel jet opening is varied by the slide, which simultaneously alters air flow. . It is controlled by a mixture needle. . It is used in side draft and updraft . Throttle Valve  The throttle valve is usually connected through a cable or a mechanical linkage of rods and joints.  Even by pneumatic mechanism.  These are connected to the accelerator pedal or any other equivalent actuaters depending on the type of vehicle.  When the actuator is completely pressed,throttle valve is opened completely when released it’s the opposite. Choke A choke is a mechanical device in a carburetor which ensures in making a rich air fuel mixture. This is required in cold starting conditions. Types: Manual choke Automatic Choke (Thermostatic operation)

Types of Carburetor Natural or Side draft.

Down draft.

Up draft. Natural or Side draft Down draft Up Draft Fuel Pump of C.S It is used to deliver fuel from the fuel tank to the corburetor. Types Mechanical fuel pump Electronic fuel pump Parts of a fuel pump Body Diaphragm Inlet/outlet valve Inlet/outlet nozzle Rocker lever Pivot pin Lever return spring Diaphragm spring  seal Diaphragm chamber. Exploded view of a pump Float and float chamber HISTORY AND DEVELPOMENT • Technology Has Been Developed Around 1920’s. • Rudolph Diesel Contracted With Awgsburg And Krupp Of Germany In 1893 To Develop A More Efficient Internal Combustion Engine. • His First Experiment On Oil Was Not Satisfactory Probably Because Of The Crude Injection Equipment With Large Dead Fuel Volume. • Dr.Diesel Resorted To Use The Compressed Air Equipment Available From The Coal Dust Experiments. • His First Experiment With Air Injection Proved So Successful That This Become The Accepted Method Of Injection Of Many Years. • Robert Bosch In Germany Developed The First Petrol Injection System For Mercedes Racing . FUEL INJECTION SYSTEM • Diesel fuel injection system: • Injects fuel in to the combustion chamber of a when the piston reaches near the compression top dead centre. Injection is high pressure • Petrol injection system: • Spray of fuel is injected in the induction manifold near inlet valve during suction when intake valve is opened.Injection is low pressure MERCEDES BENZ SL300 Types of petrol injection

1.ACCORDING TO THE LOCATION OF INJECTOR: Direct injection Port injection Throttle body injection 2.ACCORDING TO THE DURATION AND TIMING OF FUEL: Continuous type Intermittent type Sequential type 3.ACCORDING TO NUMBER OF INJECTORS: Single point injector Multi point injector 4.ACCORDING TO CONTROL METHOD: Mechanical method Electronic method Gasoline-Engine Fuel Delivery Systems Direct (In-) Fuel- Injection

1996 ????

Advanced Multi-Port- Fuel-Injection

1995 ???? Multi-Port-Fuel-Injection

1980 ???? Single-Point, Throttle-Body Fuel Injection

1980 1995

Carburetor 1900 1985 OBJECTIVES OF THE INJECTION

The injection system of theSYSTEM compression ignition engine should fulfill the following objectives consistently and precisely: 1. Meter the appropriate quantity of fuel, as demanded by the speed of, and the load on, the engine at the given time. 2. Distribute the metered fuel equally among cylinders in a multi- cylinder engine. 3. Inject the fuel at the correct time (with respect to crank angle) in the cycle. 4. Inject the fuel at the correct rate (per unit time or crank angle degree). 5. Inject the fuel with the correct spray pattern and sufficient atomization as demanded by the design of the combustion chamber, to provide proper penetration also. 6. Begin and end injection sharply without dribbling or after injection. To accomplish these objectives, a number of functional elements are required. These constitute together, the fuel injection system of the engine. These elements are as follows. 1. Pumping elements to transfer the fuel from the tank to the cylinder, along with the associate piping and hardware. 2. Metering elements to measure and supply the fuel at the rate as desired by the speed and load conditions prevailing. 3. Metering controls to adjust the rate of the metering elements for changes in load and speed of the engine. 4. Distributing elements to divide the metered fuel equally among the cylinders in a multi cylinder engine. 5. Timing controls to adjust the start and stop of injection. 6. Mixing elements to atomize and distribute the fuel within the combustion chamber FUEL SUPPLY SYSTEM

IT CONSISTS OF, • STORAGE TANK • FILTER • FUEL PUMP • FUEL INJECTOR • NOZZLE • OIL GAUGE IN THE DASH BOARD AND NECESSARY CONNNECTIONS AND PIPE LINES.

Port-Fuel-Injection

Carburetor

Direct-Injection Fuel injection systems

There are two main classifications for fuel-injection systems, namely 1. Air injection which had become obsolete but now some interest has been shown by researchers (however very high pressure is required for air) and 2. Solid (or airless) injection systems. The airless, mechanical, or solid injection systems consist of three types.

1. Individual pump system: this consists of a separate metering and compression pump for each cylinder. 2. Distribution system: this consists of a single pump for compressing the fuel (which may also meter), plus a delivery device for distributing the fuel to the cylinders (which may also meter). 3. Common rail system: a single pump for compressing the fuel, plus a metering element for each cylinder.

Fuel Filters

A low pressure (2.5 bar) transfer pump or fuel feed pump is required to lift the fuel from the tank, to overcome the pressure drop in the filters, and to charge the metering or pressuring unit. Three filters are recommended, namely,

1. A primary stage (a metal- edge filter to remove coarse particles, larger than 25 microns).

2. A secondary stage (a replaceable cloth, paper or lint element to remove fine particles from about 4 to 25 microns) and

3. Final stage (a sealed, non-replaceable element) to remove fine particles that escaped the secondary stage. The volume of fuel injected per second, Q, is given by

.  2    60   Ni  Q   d V f      4   360 N   60  where d is the diameter of one orifice in m,

Ni is the number of injections per minute, = N/2 for a 4-stroke engine, N is the engine speed in rev/min, θ is the duration of injection in crank angle degrees, Q is expressed usually in mm3/degree crank angle/liter cylinder displacement volume UNIT - V DIGITAL ENGINE CONTROL SYSTEM Anti-Lock Braking System- ABS In-Detail Originally developed for Aircraft Purpose of ABS

• Applying brakes harder under slippery surfaces causes the wheels to lock. • When wheels get locked the steering control is lost and in most cases it causes longer stopping distance. • The Anti-Lock Braking system prevents wheel’s locking or skidding, no matter how hard the brakes are applied or how slippery the road surface is. • Steering is under control and the stopping distance is reduced generally. ABS - Generation Real Time Model

ABS Requirements

• Steerability • Stability • Reduction of tire wear • Reducing stopping distance • Low Noise • High Reliability • Safety • Low cost Concept??? Which sensor signal could be used? 1.Wheel Speed 2.Vehicle Speed Vs. Ground 3.Vehicle Acceleration 4.Wheel Brake Pressure 5.Master Cylinder Pressure Components in ABS

Anti-Lock Braking System consists of the following components, • Brake pedal • Master Cylinder • Wheel Speed Sensor • Electronic Control Unit • Hydraulic Control Unit • Toothed rotor Hydraulic Control Unit Wheel Speed Sensor

??? ABS Hydraulic Operation

• It consists of an Electronic Control Unit(ECU) which controls the hydraulic pressure of fluid, either by releasing the lock on the wheel or applying brake on the wheel Road Conditions • Dry • Wet • Ice • Oil ABS Braking Cycle Operations • Pressure Isolate • Pressure Dump • Pressure Built/Normal

Cruise Control ?#@!

123 Cruise Control System

 Cruise control system controls the speed of your the by adjusting the throttle position. The throttle valve controls the power and speed of the engine by limiting how much air the engine takes

 Cruise control systems use a PID control scheme

 Distance - Integral factor (The integral of speed is distance)

 Speed - Derivative factor (The derivative of speed is acceleration)

124 Adaptive Cruise Control (ACC)

 Adaptive Cruise Control (ACC) is a feature that allows a vehicle's cruise control system to adapt the vehicle's speed to the traffic environment.

 It’s a radar-based system that can monitor the vehicle in front and adjust the speed of the vehicle to keep it at a pre-set distance behind the lead vehicle, even in most fog and rain conditions.

 The system measures distance as a function of speed and can monitor the traffic ahead while ignoring stationary objects such as road signs and telephone poles.

125

ACC Radar

 ACC is achieved through a radar headway sensor, digital signal processor and longitudinal controller.

 The 77-GHz Auto cruise radar system made by TRW has a forward- looking range of up to 492 feet (150 meters), and operates at vehicle speeds ranging from 18.6 miles per hour (30 kph) to 111 mph (180 kph).

 Delphi's 76-GHz system can also detect objects as far away as 492 feet, and operates at speeds as low as 20 mph (32 kph).

127 Constituents of ACC System

 A sensor (LIDAR or RADAR) usually kept behind the grill of the vehicle to obtain the information regarding the vehicle ahead. The relevant target data may be velocity, distance, angular position and lateral acceleration.

 Three radar beams together with an integrated yaw rate sensor, enable the system to differentiate between vehicles in the same lane and those in other lanes.

 Longitudinal controller which receives the sensor data and process it to generate the commands to the actuators of brakes throttle or gear box using Control Area Network (CAN) of the vehicle.

128 Classification of ACC Today’s modern system has evolved from the basic cruise control system. Each succeeding evolution has increased its functionality over the previous evolution. Based on the application of ACC system can be broadly classified into

 Longitudinal ACC

 Distance Control

 Stop & Go

 Lateral ACC

 Lane Detection/keeping/Changing

 Collision Avoidance

 Co-operative ACC

129

Vehicles supporting ACC Full cruise control (able to bring the car to a complete stop):

 BMW 7 Series, 5 series, 6 series Active Cruise Control with "Stop & Go" option, 2007+ models. (radar)

 Mercedes-Benz Models equipped with "Distronic Plus" ACC with "Presafe Brake" option. (radar) Partial cruise control (cuts off below a set minimum speed, requiring driver intervention):

 Audi A4 (see a demonstration on YouTube), A5, Q5, A6, A8 (uses also data from navigation and front camera sensors)

 2004 Cadillac XLR, 2005 STS, 2006 DTS (shuts off below 25 mph)

 2007 Chrysler 300C (laser, for a limited time, now uses a Bosch radar- based system)

131  2011 Dodge Charger (radar, by Bosch)

 2003 Honda Inspire, Legend, 2007 Honda CR-V series III - Adaptive Cruise Control and Collision Mitigating Braking System

 Hyundai Genesis (Smart Cruise Control, delayed)

 2011 Jeep Grand Cherokee (radar, by Bosch) 1998 Nissan Cima, Nissan Primera T-Spec Models (Intelligent Cruise Control)

 2010 Porsche Panamera, 2011 Porsche Cayenne

 Subaru Legacy & Outback Japan-spec called SI-Cruise

 1997 Toyota Celsior, 2009 Sienna (XLE Limited Edition), Avalon, Sequoia (Platinum Edition), Avensis, 2009 Corolla (Japan),[19] 2010 Prius

 Volkswagen Passat, Phaeton all generations, Touareg

 Volvo S80, V70, XC70, XC60, S60

132 Vehicle Instrumentation

Displays and Accessories To be measured • Fuel level • Temperature • Engine Speed • Oil Pressure ELECTRONIC CONTROL UNIT (ECU) (OR) BODY COMPUTER MODULE(BCM) Instrument Computer The instrument computer has three main stages of operation: Input Output stage stage  Input.  Processing.  Output. The input stage processes both analogue and digital inputs.

Some input devices Analogue require a reference voltage to function. Digital/ This is provided by the switch BCM’s power supply.

Analogue voltages are converted to digital signals by the Processing A/D converter and / or amplifier, ready for processing. stage

Weak or noisy digital signals are conditioned, ready for processing. FUEL LEVEL INDICATOR & TEMPERATURE GAUGE Fuel Level Indicator

Fuel level Speaker sensor Lamp

BCM

Digital display Analogue Display Bimetal fuel and temperature gauge circuits Voltage Stabilizer SPEEDOMETER Mechanically Driven Analogue Speedometer

Flexible Speedometer head inner cable

Outer cable housing

Cable inner wire and gear

Drive gear Transmission housing Electronically Driven Speedometer Computer (ECU)

Analogue signal

Trigger wheel Analogue or digital display

Speed sensor

Transmission housing Vehicle Instrumentation

Displays and accessories A magnetic coil gauge contains two coils and an armature/needle Magnetic Coil Gauge Armature/needle It has three terminals, two for voltage connection and one for sensor connection DC Ground voltage Magnetic fields are produced in when voltage is applied to the High Low gauge and current flows coil coil through the coils

The armature is moved by the Gauge magnetic fields. Direction housing depends upon the magnetic Input from field strength of each coil sensor 146 When the sensor has a low resistance, a high current flows through the low coil and the sensor. The magnetic field of the low coil dominates that of the high Magnetic Coil Gauge coil, and the armature moves toward the low coil Operation When the sensor has a high resistance, a low current flows High Low through the low coil and the coil coil sensor. The magnetic field of the high coil dominates that of the low coil, and the armature moves +V toward the high coil Magnetic coil gauges are normally High Low packaged in metal or plastic cases coil coil that have transparent covers and easy to read dials 147 +V Magnetic Coil Fuel Gauge Measures the amount of The magnetic field of low fuel in a fuel tank, using a coil dominates and the float attached to a needle points toward full variable resistor (sensor). (F) on the fuel gauge When the fuel level in the tank is low, the float The float rises as the tank drops and the resistance fills, lowering sensor of the sensor is high resistance, allowing more The magnetic field of current flow through the low coil high coil dominates and the needle points toward empty (E) on the fuel gauge

148 Magnetic Coil Oil Pressure Gauge A diaphragm, in conjunction with a variable resistor, is used to measure engine oil pressure. As the diaphragm deflects, the resistance measured at the input to the oil pressure gauge varies.

The gauge is usually mounted on the dashboard.

A warning lamp can be used to indicate low oil pressure. It illuminates at a preset resistance value. Lam p