DOCSLIB.ORG

Gas Exchange Process for IC-Engines: Poppet Valves, Valve Timing and Variable Valve Actuation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gas Exchange Process for IC-Engines: Poppet Valves, Valve Timing and Variable Valve Actuation Gas exchange process for IC-engines: poppet valves, valve timing and variable valve actuation Topics Analysis of the main parameters influencing the volumetric efficiency in IC engines: - Valves and valve timing - Dynamic effects - Turbocharging Introduction At the end of each cycle, in an IC engine the burned gases have to be replaced by new charge of air/fuel and (often) recycled exhaust gases. The gas exchange process is quite complex since it involves many time-dependent phenomena, such as: unsteady and compressible flows, frictional losses, heat transfers, area changes and complex geometrical paths. During the gas exchange process, because of the cyclic operation of cylinders, the flows through each component are pulsating and strongly influenced by inertia effects and wave actions, and hence difficult to be analyzed. Layout of the intake and exhaust systems for a 4- stroke, TC, SI engine. Volumetric efficiency or filling coefficient Volumetric efficiency (ηv) or filling coefficient (λv), defined as: ma: trapped air mass per cycle mt: theoretical amount of mass that can fill the cylinder displaced volume ρa: air density at reference conditions V: cylinder displaced volume The filling coefficient measures the engine capability to fill its displacement with air. For this reason, it is defined as the ratio between the trapped air mass per cycle and the theoretical amount of mass that can fill the engine displacement at reference conditions. The actual air mass, ma, aspirated inside the cylinder at the end of the single cycle, is different from the ideal one mt, for different reasons: 1) Burned gases inside the combustion chamber Vc at the end of the exhaust process, have a pressure pr which is higher than the atmospheric pressure pa. Therefore, burned gases expand, at the beginning of the induction stroke, filling part of the displacement Vd (that, instead, should be filled by fresh charge). 2) Pressure inside the cylinder at the end of the induction stroke is lower than pa, because energy must be spent to overcome frictional losses along the induction system and to accelerate the fluid through the inlet ports. The inlet valve does not close at BDC (point 1), but somewhat later at the beginning of the compression stroke (point i), where is pi> pa. However, the available volume Vi for fresh charge is then lower than V1, hence the loss in filling is evident. 3) During the intake exchange process, heat is exchanged between the hot engine walls and the entering fresh fluid, increasing the temperature of the new charge and hence decreasing the air density inside the cylinder at the end of the induction process. 4) The gas exchange process is influenced by dynamic effects, due to unsteady flows and pressure wave actions, which can improve or hinder the cylinder filling, depending on whether the geometry of the induction system is tuned or not with available times. To overcome this limitation, some car engines use now induction systems of variable geometry with the rotational speed. 5) For reasons of simplicity, cost and reliability, the conventional engines are equipped with a fixed angular valve timing. This means that the crank angles of valve opening and closing does not vary with the engine rotational speed n. For this reason, times available for the exchange process decrease when the engine speed increases. Hence fixed timings (with fixed geometry) can be optimized just for a limited engine speed range. A first estimation of the filling coefficient (λv) can be achieved by applying the energy conservation to the intake process: which, after some manipulation, can lead to the following expression: Numerical fluid dynamic models are needed for more accurate predictions. Dependency of the volumetric efficiency from the engine speed: 1) CURVE A: Non- dependent speed effects (like fuel vapour pressure) drop ηv below 100% 2) CURVE B: Charge heating in the manifolds and cylinder drops curve A to curve B. It has a greater effect at lower engine speeds, due to the longer gas residence times. 3) CURVE C: Frictional flow losses increase as the square of the engine speed, and drop curve B to curve C. 4) CURVE D: At higher engine speeds, the flow into the engine during at least part of the intake process becomes chocked. Once it occurs, further increases in speed do not increase the flow rate significantly, so volumetric efficiency decreases sharply (curve C to curve D). 5) The induction ram effect, at higher engine speeds, raises curve D to curve E. Late inlet valve closing, which allows advantage to be taken of increased charging at higher speeds, results in a decrease of ηvat low engine speeds due to backflow (curves C and D to F). Finally, intake and/or exhaust tuning can increase the volumetric efficiency (often by a substantial amount) over part of the engine speed range, curve F to G. Poppet Valves In a four-stroke engine, the most significant flow restriction, along all the intake and exhaust systems, is usually located in the poppet valves. For this reason, the flow through these engine components has to be analyzed. Modern four-stroke engines usually control the opening and closing of the intake and exhaust ports of the cylinders by poppet valves. They offer: - Minimum fluid-dynamic losses - High sealing ability and good reliability while subjected to high accelerations (and hence inertia forces). The quantity of heat absorbed by the valve when heat is released from the products of combustion amounts roughly to 70% by conduction through the valve head when it is closed, and 30% by conduction through the fillet underside of the valve when it is open and the exhaust gas is escaping through the exhaust port. When the valve is closed, about 76% of the total heat input from the heat released by combustion is transferred by conduction to the cylinder head coolant by way of the valve seat, and only 24 % of the total heat input to the valve is conveyed through the valve stem to the cylinder head coolant via the valve guide. High operating temperatures due to incorrect ignition timing and mixture strength raise the valve head temperature until the valve head becomes the focal point for pre-ignition. A portion of the valve head then becomes the point of ignition which again leads to further heating of the valve head until eventually the valve seat distorts. Consequently, the poor seating of the valve during the combustion phase provides an escape route for some of the burning gases and, as a result, causes excessive local overheat and burning in the valve rim and seat region. If large quantities of combustion products accumulate around the valve seat they will eventually become dislodged due to the repeated valve closing impact, some of the break-away deposits will then provide exit passages for the burning gases. The partial radial tunnelling around the valve seat when it is closed will therefore cause the valve seat to overheat as the gas escapes, since the heat flow path around the head is interrupted. This may result in severe carburization and oxidation of the valve seat surface, and ultimately it may burn a semiconcave groove into and around the valve seat. The name 'guttering' is derived from the top face contour of house guttering. Flow coefficient Flow through a valve is mainly influenced by the available area and the pressure head across cylinder and pipe. The valve flow area (both exhaust and intake) is rapidly varying with time, or better it is a function of crank angle θ, which is proportional to time, for a given shaft rotational speed ω. The pressure upstream the valves changes continuously with time, therefore the flow through the valve results highly unsteady. It is also turbulent, and some useful information can be drawn from flow tests in steady-state conditions. The figure illustrates the main device used in these flow tests. Direct flow (from the manifold to cylinder): through the actual port-valve group (or a preliminary model), air is aspirated by a fan located in the cylinder, to simulate the piston effect. Reverse flow (from the cylinder to the pipe): in this case, the fan is pressuring the cylinder. In both cases, the lift is kept constant and, at steady flow conditions, actual air mass flow rates are measured, for different valve lifts and pressure heads Δpv across the valve. To derive more general information about the flow, that may be extended to other engines operating at similar fluid-dynamic conditions, the measured actual air mass flow rate values are made dimensionless by dividing them by the ideal mass flow rates that would pass through a reference area Avref under the same Δpv in an iso-entropic expansion. This is the valve flow coefficient C: ma = measured air mass flow rate mid = ideal air mass flow rate that would pass through a reference area Avref under the same Δpv in an iso-entropic expansion. Avref = is the reference area, set to be constant and equal to the inner seat area: The flow coefficient for fully turbulent flow is independent on Re. where a01 is the total speed sound in 1 and the compressible flow function is: m* is the critical or sonic mass flow. The flow coefficient includes not only the typical losses of the actual flow (friction, heat exchange, energy dissipation, etc.), but also effects of continuous change in geometric flow area. Since the flow is fully turbulent, the effect of Δpv is negligible, and typical values of C are usually plotted as function of l/dv (non-dimensional valve lift). C is increasing with l/dv since the geometric flow area increases, but it do not reach values near unity because the ideal flow rate is referred to Avref, that is greater than the actual one, even at lmax.
Load more

Recommended publications
  • Spark Plug Condition Chart
    Spark Plug Condition Chart Normal Mechanical Damage Oil Fouled May be caused by a foreign object that Too much oil is entering the combustion has accidentally entered the combus- Combustion deposits are slight chamber. This is often caused by piston tion chamber. When this condition is and not heavy enough to cause rings or cylinder walls that are badly discovered, check the other cylinders to any detrimental effect on engine worn. Oil may also be pulled into the prevent a recurrence, since it is possi- performance. Note the brown to chamber because of excessive clear- ble for a small object to "travel" from greyish tan color, and minimal ance in the valve stem guides. If the one cylinder to another where a large amount of electrode erosion which PCV valve is plugged or inoperative it degree of valve overlap exists. This clearly indicates the plug is in the can cause a build-up of crankcase pres- condition may also be due to improper correct heat range and has been sure which can force oil and oil vapors reach spark plugs that permit the piston operating in a "healthy" engine. past the rings and valve guides into the to touch or collide with the firing end. combustion chamber. Overheated Insulator Glazing Pre-Ignition A clean, white insulator firing tip and/or excessive electrode ero- Usually one or a combination of several sion indicates this spark plug con- Glazing appears as a yellowish, var- dition. This is often caused by over engine operating conditions are the nish-like color. This condition indicates prime causes of pre-ignition.
    [Show full text]
  • The Effect of Turbocharging on Volumetric Efficiency in Low Heat Rejection C.I. Engine Fueled with Jatrophafor Improved Performance
    International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Vol. 4 Issue 03, March-2015 The Effect of Turbocharging on Volumetric Efficiency in Low Heat Rejection C.I. Engine fueled with Jatrophafor Improved Performance R. Ganapathi *, Dr. B. Durga Prasad** Lecturer, Professor, Mechanical Engineering department, Mechanical Engineering department, JNTUA College of Engineering, JNTUA College of Engineering, Ananthapuramu, A.P, India. Ananthapuramu, A.P, India. burned. This can be achieved with an LHR engine dueto Abstract:- The world’s rapidly dwindling petroleum the availability of higher temperature at the time of fuel supplies, their raising cost and the growing danger of injection. The heat available due to insulation can be environmental pollution from these fuel, have some effectively used for vaporizing alternative fuel. Some substitute of conventional fuels, vegetable oils has been important advantages of the LHR engines are improved fuel considered as one of the feasible substitute to economy, reduced HC and CO emission, reduced noise due conventional fuel. Among all the fuels, tested Jatropha to lower rate of pressure rise and higher energy in the oil properties are almost closer to diesel, particularly exhaust gases [2 & 3]. However, one of the main problems cetane rating and heat value. In present work in the LHR engines is the drop in volumetric experiments are conducted with Brass Crown efficiency. This further decrease the density of air Aluminium piston with air gap, an air gap liner and entering the cylinder because of high wall temperatures of PSZ coated head and valve have been used in the the LHR engine. The degree of degradation of volumetric present study, which generates higher temperature in efficiency depends on the degree of insulation.
    [Show full text]
  • Installation Instructions SUPERCHARGER ‘90-’93 Mazda Miata Part# 999-000, 999-005, 999-010, 999-015
    Installation Instructions SUPERCHARGER ‘90-’93 Mazda Miata Part# 999-000, 999-005, 999-010, 999-015 440 Rutherford St. P.O. Box 847 Goleta, CA 93117 1-888-888-4079 • FAX 805-692-2523 • www.jacksonracing.com INSTALLATION TIME IN AS LITTLE AS 4 HOURS regularly (every 3000 miles or so), you should FOR EXPERIENCED MECHANICS, AROUND 5 have no trouble. If in doubt, check your engine’s TO 6 HOURS FOR “OCCASIONAL” MECHAN- compression. You should have at least 135psi of ICS. compression in each cylinder with no more than a 10% variance between any two cylinders or with a TOOLS REQUIRED: 3/8” Drive Socket set w/ 10% increase in any cylinder after a tablespoon of 17mm, 14mm, 13mm, 12mm, 10mm & 8mm sock- oil is poured in. Your cooling system should be up ets; Deep sockets (14mm or 9/16”, 10mm): to par (50/50 mix of water and new coolant). Phillips and Standard screwdriver, 10mm, 12mm, Basically, if you have a good engine, it will be very and 17mm open end wrench; 5mm Allen wrench happy with this supercharger. with a 3/8” drive; paper clip; a box to store your OLD PARTS in. A 1/4” drive socket set will be use- BEFORE INSTALLING THIS SYSTEM: ful with some of the tight working areas. A timing A. Drive your fuel tank empty and refill with 92 light will be needed to set the ignition timing. Octane major brand gasoline. If you can only find 91 Octane, see step #3 under “Adjustments” at the A NOTE ON ADDING A SUPERCHARGER TO end of these instructions.
    [Show full text]
  • Supercharger
    Supercharger 1 4/13/2019 Supercharger Air Flow Requirements • Naturally aspirated engines with throttle bodies rely on atmospheric pressure to push an air–fuel mixture into the combustion chamber vacuum created by the down stroke of a piston. • The mixture is then compressed before ignition to increase the force of the burning, expanding gases. • The greater the mixture compression, the greater the power resulting from combustion. Engineers calculate engine airflow requirements using these three factors: – Engine displacement – Engine revolutions per minute (RPM) – Volumetric efficiency Volumetric efficiency – is a comparison of the actual volume of air–fuel mixture drawn into an engine to the theoretical maximum volume that could be drawn in. – Volumetric efficiency decreases as engine speed increases. 2 4/13/2019 Supercharger Principles of Power Increase: The power output of the engine depend up on the amount of air induced per unit time and thermal efficiency. The amount of air induced per unit time can be increased by: Increasing the engine speed. the increase in engine speed calls for rigid and robust engine as the inertia load increase also the engine fraction and bearing load increase and also the volumetric efficiency decrease. Increasing the density of air at inlet. The increase of inlet air density calls supercharging which usually used to increase the power output from engine due to increase the air pressure at the inlet of engine. 3 4/13/2019 Supercharger The Objects of Supercharging: To increase the power output for a given weight and bulk of the engine. This is important for aircraft, marine and automotive engines where weight and space are important.
    [Show full text]
  • 2004-01-2977 IC Engine Retard Ignition Timing Limit Detection and Control Using In-Cylinder Ionization Signal
    Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015 SAE TECHNICAL PAPER SERIES 2004-01-2977 IC Engine Retard Ignition Timing Limit Detection and Control using In-Cylinder Ionization Signal Ibrahim Haskara, Guoming G. Zhu and Jim Winkelman Visteon Corporation Reprinted From: SI Engine Experiment and Modeling (SP-1901) Powertrain & Fluid Systems Conference and Exhibition Tampa, Florida USA October 25-28, 2004 400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 Web: www.sae.org Downloaded from SAE International by Brought To You Michigan State Univ, Thursday, April 02, 2015 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. For permission and licensing requests contact: SAE Permissions 400 Commonwealth Drive Warrendale, PA 15096-0001-USA Email: [email protected] Fax: 724-772-4891 Tel: 724-772-4028 For multiple print copies contact: SAE Customer Service Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-1615 Email: [email protected] ISBN 0-7680-1523-5 Copyright © 2004 SAE International Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussions will be printed with the paper if it is published in SAE Transactions.
    [Show full text]
  • Air Filter Sizing
    SSeeccoonndd SSttrriikkee The Newsletter for the Superformance Owners Group January 17, 2008 / September 5, 2011 Volume 8, Number 1 SECOND STRIKE CARBURETOR CALCULATOR The Carburetor Controlling the airflow introduces the throttle plate assembly. Metering the fuel requires measuring the airflow and measuring the airflow introduces the venturi. Metering the fuel flow introduces boosters. The high flow velocity requirement constrains the size of the air passages. These obstructions cause a pressure drop, a necessary consequence of proper carburetor function. Carburetors are sized by airflow, airflow at 5% pressure drop for four-barrels, 10% for two-barrels. This means that the price for a properly sized four-barrel is a 5% pressure loss and a corresponding 5% horsepower loss. The important thing to remember is that carburetors are sized to provide balanced performance across the entire driving range, not just peak horsepower. When designing low and mid range metering, the carburetor engineers assume airflow conditions for a properly As with everything in the engine, airflow is power. sized carburetor - one sized for 5% loss at the power peak. Carburetors are a key to airflow. As with any component, the key to best all around performance is to pick parts that match Selecting a larger carburetor than recommended will reduce your performance goal and each other – carburetor, intake, pressure losses at high rpm and may help top end horsepower, heads, exhaust, cam, displacement, rpm range, and bottom but will have lower flow velocity at low rpm and poor end. metering and mixing with a loss in low and mid range power and drivability.
    [Show full text]
  • DYNO Testing)
    TyrolSport UG Side Mount Intercooler - The new standard in upgraded Side Mount Intercoolers for 1.8T Golf/Jetta (DYNO Testing) The aftermarket for the 1.8T has been booming, as people come to realize the potential of this stout motor in a relatively light chassis. Up until now, the upgrade path for the stock intercooler has been to replace the stock Sidemount intercooler(SMIC) with a larger unit, or to scrap it altogether and go with a Front Mount unit(FMIC). It has been held as common knowledge that SMICs are inferior to FMICs in all performance applications. Regardless of turbo, horsepower, vehicle use, FMICs have trumped SMICs in popularity. Part of this due to the fact that all the big horsepower cars run FMICs. The other part seems to be that it is inconceivable to many that an SMIC can indeed perform equal to an FMIC. The goal of the TyrolSport UG SMIC was to combine the performance of an FMIC with the cost and easy packaging and installation of an SMIC. We spent the better part of a day today testing three intercoolers. The stock sidemount, The TyrolSport UG side mount(Known as the UG SMIC in the charts below), and a front mount. The aftermarket FMIC will not be named for many reasons. The TyrolSport UG SMIC mounts in the stock location, uses stock hoses, and requires minor trimming to fit. The UG SMIC uses a bar and plate Bell intercooler core. The Front Mount is a popular unit, and resides on many 1.8Ts. We will not reveal the manufacturer of the FMIC, as the purpose of this test was data acquisition; not marketing, sales, or slander.
    [Show full text]
  • All About Intercooling
    ALL ABOUT INTERCOOLING A COMPREHENSIVE GUIDE TO INTERCOOLING BY GEORGE SPEARS ALL ABOUT INTERCOOLING TABLE OF CONTENTS I. The Advantages of Intercooling II. Intercooler Basics A. What is an intercooler and what does it do? B. Vacuum furnace brazing C. C.A.B. III. Types of Assemblies and Construction of Intercoolers A. Bar and plate type B. Welded or extruded tube type IV. Air / Liquid Intercoolers V. Intercooler Efficiency or Effectiveness VI. Sizing the Intercooler and Engineering the System VII. Intercooler Performance and Testing VIII. Engine Fuel System IX. Intercooler Sizes and Fin Configuration for Special Purposes X. Oversized Intercoolers XI. Charge Air Cooling by Refrigeration XII. Water Injection XIII. Intercooler Thickness XIV. Welding Aluminum Intercooler Cores and Other Aluminum Components ALL ABOUT INTERCOOLING THE ADVANTAGES OF INTERCOOLING Intercooling a supercharged or turbocharged engine has several advantages. The first and most frequently considered advantage is increased air density with consequential increase in horsepower. As will be shown in this booklet, horsepower can be increased by as much as 18 % or more. Some of the other bene- fits of intercooling are in- creasing the detonation thresh- old. With a good intercooler you can generally run three to four ad- ditional lbs of boost with the same octane gasoline and ignition timing without ex- periencing detona- tion. An inter- cooler slightly reduces the thermal load across the en- gine. When the inlet valve closes, the charge air inside the cylinder can be as much as 175° F to 200° F cooler than a non-intercooled engine, depending on the effectiveness of the intercooler.
    [Show full text]
  • RECIPROCATING COMPRESSOR PERFORMANCE IMPROVEMENT with RADIAL POPPET VALVES 2009 GMRC Gas Machinery Conference – Atlanta, GA – October 5‐7, 2009
    RECIPROCATING COMPRESSOR PERFORMANCE IMPROVEMENT WITH RADIAL POPPET VALVES 2009 GMRC Gas Machinery Conference – Atlanta, GA – October 5‐7, 2009 Lauren D. Sperry, PE & W. Norman Shade, PE ACI Services Inc. ABSTRACT Over the past decade, radial compressor valves and unloaders have been successfully introduced into reciprocating compressors for the gas transmission industry. The unique radial valve system seats multiple rows of poppets over ports in a cylindrical sleeve that replaces the traditional cage and single‐deck valve used in a reciprocating compressor. The radial valve concept has been applied for both suction and discharge valves in a broad range of compressor models and pipeline cylinder classes. Use of these valves has resulted in significant increases in efficiency and reductions in HP/MMSCFD. For cylinder end deactivation, the cylindrical valve guard is moved to slide the poppets off their seats and away from the ports, providing a relatively unobstructed flow path for the gas. The resulting parasitic losses of the deactivated cylinder end approach the losses achieved by complete removal of a traditional valve. Use of radial valves has also been found to significantly increase unit capacity. Some of this increase stems from being able to operate the more efficient radial valved compressor with less unloading, so that there is more effective displacement utilized for the same power input. Moreover, in practice the significant added fixed volumetric clearance inherent in the radial poppet valves has not reduced the measured volumetric efficiency or the capacity as much as traditional theory would predict. This paper will present four case studies that show the actual field operating performance improvements obtained with radial poppet valves on both low speed and high speed compressors, along with laboratory test comparisons, and an explanation of why the capacity can increase even though the fixed clearance increases.
    [Show full text]
  • THERMAL EFFICIENCY", of the Engine
    PowerPower FlowFlow andand EfficiencyEfficiency Engine Testing and Instrumentation 1 Efficiencies When the engine converts fuel into power, the process is rather inefficient and only about a quarter of the potential energy in the fuel is released as power at the flywheel. The rest is wasted as heat going down the exhaust and into the air or water. This ratio of actual to potential power is called the "THERMAL EFFICIENCY", of the engine. How much energy reaches the flywheel ( or dynamometer) compared to how much could theoretically be released is a function of three efficiencies, namely: 1. Thermal 2 Mechanical 3. Volumetric Engine Testing and Instrumentation 2 Thermal Efficiency Thermal efficiency can be quoted as either brake or indicated. Indicated efficiency is derived from measurements taken at the flywheel. The thermal efficiency is sometimes called the fuel conversion efficiency, defined as the ratio of the work produced per cycle to the amount of fuel energy supplied per cycle that can be released in the combustion process. Engine Testing and Instrumentation 3 B.S. = Brake Specific Brake Specific Fuel Consumption = mass flow rate of fuel ÷ power output bsHC = Brake Specific Hydrocarbons = mass of hydrocarbons/power output. e.g. 0.21 kg /kW hour Engine Testing and Instrumentation 4 Thermal Efficiency Wc Ps ηt = = m f QHV µ f QHV Wc − work _ per _ cycle Ps − power _ output m f − mass _ of _ fuel _ per _ cycle QHV − heating _ value _ of _ fuel µ f − fuel _ mass _ flow _ rate Specific fuel consumption µ Sfc = f Ps Therefore 1 3600 82.76 ηt = = = Sfc ⋅QHV Sfc(g / kW ⋅hr)QHV (MJ / kg) Sfc Since, QHV for petrol = 43.5 MJ/kg Therefore, the brake thermal efficiency = 82.76/ sfc The indicated thermal efficiency = 82.76 / isfc Engine Testing and Instrumentation 5 Mechanical Efficiency The mechanical efficiency compares the amount of energy imparted to the pistons as mechanical work in the expansion stroke to that which actually reaches the flywheel or dynamometer.
    [Show full text]
  • Timing/Synchronizing/ Adjusting
    Timing/Synchronizing/ Mariner 75 Marathon/Merc 75XD Adjusting (3 Cylinder Models) Full Throttle RPM Range 4750 - 5250 Idle RPM (in “FORWARD” Gear) 650 - 700 Specifications Maximum Timing @ 5000 RPM 16 _ B.T.D.C. 70, 75 and 80 Models (@ Cranking Speed) (18 _ B.T.D.C.) _ _ Serial Number and Above Idle Timing 0 - 4 B.T.D.C. Spark Plug NGK BUHW-2 U.S. B239242 Firing Order 1-3-2 Belgium 9502135 Canada A730007 Special Tools Full Throttle RPM Range 4750 - 5250 Part No. Description Idle RPM (in “FORWARD” Gear) 650 - 700 *91-58222A1 Dial Indicator Gauge Kit Maximum Timing @ 5000 RPM 26 _ B.T.D.C. *91-59339 Service Tachometer (@ Cranking Speed) (28 _ B.T.D.C.) *91-99379 Timing Light _ _ Idle Timing 0 - 4 B.T.D.C. 91-63998A1 Spark Gap Tool Spark Plug NGK BUHW-2 Firing Order 1-3-2 * May be obtained locally. Timing Pointer Adjustment 70, 75 and 80 Models Serial Number and Below WARNING U.S. B239241 Engine could start when turning flywheel to chec k Belgium 9502134 timing pointer alignment. Remove spark plugs from engine to prevent engine from starting. Canada A730006 1. Install Dial Indicator P/N 91-58222A1 into no. 1 Full Throttle RPM Range 4750 - 5250 (top) cylinder. Idle RPM (in “FORWARD” Gear) 650 - 700 2. Turn flywheel clockwise until no. 1 (top) piston is at top dead center (TDC). Set Dial Indicator to “0” Maximum Timing @ 5000 RPM 22 _ B.T.D.C. (zero). (@ Cranking Speed) (24 _ B.T.D.C.) Idle Timing 0_ - 4 _ B.T.D.C.
    [Show full text]
  • Effect of Various Ignition Timings on Combustion Process and Performance of Gasoline Engine
    ACTA UNIVERSITATIS AGRICULTURAE ET SILVICULTURAE MENDELIANAE BRUNENSIS Volume 65 58 Number 2, 2017 https://doi.org/10.11118/actaun201765020545 EFFECT OF VARIOUS IGNITION TIMINGS ON COMBUSTION PROCESS AND PERFORMANCE OF GASOLINE ENGINE Lukas Tunka1, Adam Polcar1 Department of Technology and Automobile Transport, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic Abstract TUNKA LUKAS, POLCAR ADAM. 2017. Effect of Various Ignition Timings on Combustion Process and Performance of Gasoline Engine. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 65(2): 545–554. This article deals with the effect of the ignition timing on the output parameters of a spark-ignition engine. The main assessed parameters include the output parameters of the engine (engine power and torque), cylinder pressure variation, heat generation and burn rate. However, the article also discusses the effect of the ignition timing on the temperature of exhaust gases, the indicated mean effective pressure, the combustion duration, combustion stability, etc. All measurements were performed in an engine test room in the Department of Technology and Automobile Transport at Mendel University in Brno, on a four-cylinder AUDI engine with a maximum power of 110 kW, as indicated by the manufacturer. To control and change the ignition timing of the engine, a fully programmable Magneti Marelli control unit was used. The experimental measurements were performed on 8 different ignition timings, from 18 °CA to 32 °CA BTDC at wide throttle open and a constant engine speed (2500 rpm), with a stoichiometric mixture fraction. The measurement results showed that as the ignition timing increases, the engine power and torque also increase.
    [Show full text]