Showing papers on "Spark-ignition engine published in 1974"

Extension of the Lean Misfire Limit and Reduction of Exhaust Emissions of an SI Engine by Modification of the Ignition and Intake Systems

Abstract: The lean misfire limit air-fuel ratio of a spark ignition engine was extended by various modifications of the intake and ignition systems. The effects of long duration spark, extended spark plug gap projections and gap widths, and a vaned collar intake valve are reported. These modifications allowed for reliable operation up to air-fuel ratios of 24:1. The experimental apparatus and procedure used in this study are described. Conclusions are drawn concerning the optimization of the various modifications to extend the lean misfire limit and reduce the exhaust emissions.

Spark ignition engine using lean air-fuel mixture

Abstract: In a spark-ignition engine of the type having a main combustion chamber and an auxiliary combustion chamber so as to ignite the lean air-fuel mixture, a passage intercommunicating between the main and auxiliary combustion chambers has a bent portion between the ends thereof, and the spark gap of a spark plug is placed at or in the vicinity of the bent portion in the passage.

Calculated nitric oxide emissions of an unthrottled spark ignited, stratified charge internal combustion engine

Abstract: This paper presents a theoretical study of nitric oxide emissions from an unthrottled stratified charge, spark ignition engine. A three-region (generally rich, stoichiometric, and lean) combustion model was used, and the effects of the following variables were studied: 1. Excess air number of the rich mixture. 2. Percentage of the total fuel in the rich-mixture region. 3. Percentage of fuel burned stoichometrically. 4. Exhaust gas recirculation, percentage and distribution. Comparisons are made to both experimental results from a throttled engine and calculated results for an unthrottled engine with a homogeneous mixture. For illustrative purposes, an application of the model to a particular geometrical form of charge distribution is analyzed.

Cycle by cycle variability in emissions of a spark ignition engine

Abstract: The exhaust emissions from a single-cylinder spark ignition engine were measured as a function of burning time Tests were carried out at full throttle, for lean, optimum, and rich A/F The exhaust components measured were CO, HC, 02, H2, N2 using a gas chromatograph The emission most affected by CBCV is CO Cycles that are either faster or slower than the mean cycle have increased CO, particularly at lean A/F where a five-fold difference in CO concentration was measured HC emissions show a 150% change for the same conditions A reduction in CBCV would also reduce overall CO and HC emissions, particularly for very lean operation /GMRL/

Spark ignition engine having combustion chamber provided with vent valve

Abstract: A vent valve allows a combustion chamber arranged to burn a swirling lean mixture to communicate with either an intake manifold or exhaust manifold through a vent port by-passing the intake or exhaust valve, for a short period just before ignition to discharge a fraction of the mixture from the combustion chamber. The discharge weakens the turburent flow of the mixture and results in a decreased combustion temperature, which is advantageous for suppression of NOx formation and prevention of combustion noise generation.

Combustion chamber structure for a spark ignition engine

Abstract: A spark ignition engine of the carburetor single chamber type stratified charge combustion system wherein air and rich mixture are supplied successively by the same path, comprising a barrier arranged in the combustion chamber for directing the intake gas flow, said barrier projecting from the wall of the combustion chamber into the interior of the combustion chamber, whereby the air and rich mixture are positively stratified in the order in which they are drawn into the combustion chamber.

Analysis of nitric oxide formation in spark ignition engine with heat transfer and effect of ignition point

Abstract: The formation of nitric oxide in the combustion chamber of a spark ignition engine is formulated by developing a simple model. The state of the gas in the chamber and its thermal properties are estimated during a complete cycle. A simple heat transfer relation is used to estimate the heat loss from the gas to the chamber walls. The effect of the position of the ignition source relative to the exhaust port is also taken into account, and the predicted nitric oxide concentrations are compared with experimental results from a single-cylinder variable compression ratio IFP engine. It is found that the nitric oxide concentration predicted by the model agrees well over most of the operating range with the experimentally measured nitric oxide concentrations in the exhaust gas.

Passenger Car Performance With the Experimental Gas Turbine VW—GT 70

Abstract: The performance obtained by the Volkswagenwerk AG with an experimental gas turbine power plant in a passenger car is described. The power unit and its installation in the vehicle are described, and results of operational tests are given. The investigations covered both the road performance and the effect on the environment of the experimental turbine car. The results are compared with those from spark ignition engines of similar power. Possible solutions are indicated where the results are considered to be not yet satisfactory. The turbine car met proposed emission standards up to 1976 for hydrocarbons, carbon monoxide, and nitrogen oxides. The NOx emissions were too high to meet the 1977 standards, however. The relationships of fuel consumption and engine operating cycles with emissions were also studied.