Showing papers on "Spark-ignition engine published in 1976"

The variation of ionization with air/fuel ratio for a spark‐ignition engine

Abstract: A negatively biased flush‐mounted planar probe operated both in a pulsed and dc mode has been used to measure the ionization density in the plasma generated by combustion in a single‐cylinder spark‐ignition engine. The ionization was measured as a function of the air/fuel ratio and was found to exhibit a broad peak (Q?2) whose maximum occurs slightly to the rich side of stoichiometric. The peak ionization was calculated from two slightly different models for ion collection to be ?1019/m3. Values of this magnitude appear to be more reasonable than the very high value of 4×1021/m3 deduced by Rado using a similar experimental setup. Finally, it is proposed that this type of measurement may be useful to monitor engine performance.

Water-gasoline fuels -- their effect on spark ignition engine emissions and performance

Abstract: Single-cylinder engine tests, an analytical engine cycle simulation, and automobile tests were employed to study the effects of supplementing gasoline with water for use in spark ignition engines. Factors examined include: the method of water addition (both water-in-gasoline emulsions and direct manifold water addition), antiknock characterisitics with water additione, MBT spark requirement, indicated engine efficiency, engine cooling requirement, exhaust emissions, volumetric efficiency, lean operating limit, smoke level, exhaust temperature, and vehicle driveability. Among the negative aspects of water addition were increased hydrocarbon emissions and decreased vehicle driveability. Also, the polyoxyethylene type of emulsifier used in the water-in-gasoline emulsions, gave poor fuel stability and caused a rapid buildup of engine deposits. However on the positive side, water-gasoline fuels have higher octane ratings and decrease nitric oxide emissions.

Device for optimum control of the sparking time of a spark ignition engine, during its operation

Abstract: This device comprises, in combination, means generating a digital value equal to the difference between a number of cycles of the engine and the number of knockings detected during the period of said cycles and means controlling the spark advance point in response to said difference.

A Statistical Analysis of the Influence of Cyclic Variation on the Formation of Nitric Oxide in Spark Ignition Engines

Abstract: A statistical method is presented to study the influence of cyclic variation of the combustion process on the formation of nitric oxide in spark ignition engines. In the analysis, each engine cycle was treated as a realization of a random experiment. Specifically, the cylinder pressure as a function of crank angle was considered a stochastic process, and the nitric oxide concentration frozen in the expansion stroke was considered a random variable associated with the random experiment. A set of consecutive cylinder pressure-crank angle data furnished the statistical properties of the cylinder pressure of a spark ignition engine at a normal running condition. The stochastic process of cylinder pressure was first approximated by one degree of randomness expression with peak combustion pressure as the characterizing random variable. Secondly, a combustion and nitric oxide kinetics model was used to establish the functional relationship of frozen nitric oxide concentration to cylinder pressure, particularly to the peak combustion pressure. Finally, the probability density function of the nitric oxide concentration was calculated by using the fundamental theorem of functions of random variables.

Single Cylinder Spark Ignition Engine Study of the Octane, Emissions, and Fuel Economy Characteristics of Methanol-Gasoline Blends

Abstract: Test program was carried out on a single cylinder, fuel research engine (CFR) to determine the octane, emissions, and fuel economy characteristics of methanol-gasoline blends. The first phase of the work was an evaluation of the octane characteristics of methanol blended with unleaded gasoline. The second phase of the test program was an evaluation of the emissions and fuel economy of a 10% by volume blend of methanol with two base fuels in the single cylinder engine. Genral conclusions were that a blend of 10% methanol and gasoline demonstrated no significant change in the emissions or energy efficiency over the gasoline fueled engine when operated at equivalent conditions. Under some operating conditions, the addition of methanol could increase the octane rating of the base fuel. /GMRL/

Rich core stratified charge spark ignition engine with peripheral exhaust port

Abstract: Spark ignition internal combustion engine arrangements are disclosed wherein swirling stratified charges are formed in the engine combustion chambers, each charge having a central core of relatively fuel-rich mixture and a surrounding peripheral portion of leaner mixture or air, and in which the exhaust valve for each chamber is connected with the fuel-lean peripheral portion so that during the exhaust process the portions of the burned gases which are lowest in unburned hydrocarbons will be preferentially exhausted, leaving those portions richest in hydrocarbons as residual gases within the chamber.

Performance of methanol-gasoline blends in a stratified charge engine vehicle

Abstract: A series of driveability and chassis dynamometer tests were performed using various blends of methanol and gasoline in a stratified charge engine vehicle. The vehicle used was a 1975 Honda Civic CVCC. This vehicle is powered by a prechamber type stratified charge spark ignition engine. The test program was separated into two phases. The first phase was to determine the effect of methanol-gasoline blends on the driveability of the stratified charge engine vehicle. Blends containing 10% to 40% by volume of methanol in gasoline were tested. A weighted demerit system was used to evaluate driveability. Emissions and fuel economy of the vehicle operating on base fuels and base fuels blended with methanol were evaluated using a chassis dynamometer and the federal urban driving schedule. General conclusions are that the CVCC vehicle tested suffered only slight degradation in driveability using a 10% methanol-gasoline fuel and vehicle emissions and fuel economy are not significantly changed by use of the 10% methanol blend.

Cylinder firing indicator

Abstract: In a cylinder compression test apparatus for a spark ignition engine, imped means for generating an electrical pulse representing the fire period for a selected cylinder. The mechanism is useful during engine compression test for correlating each measured waveform with the cylinder that produced that particular waveform.

Method of operating a spark ignition engine

Abstract: A method of operating a spark ignition internal combustion engine having a main combustion chamber into which there is introduced a fuel-lean mixture of fuel and air, an auxiliary combustion chamber into which there is introduced a fuel-rich mixture of fuel and air, and an ignition means located in said auxiliary combustion chamber. In said method the engine is operated to approach an extended minimum lean misfire limit, and thus obtain minimum emissions of objectionable pollutants, e.g., nitrogen oxides. Said method comprises providing the engine with an auxiliary combustion chamber having a predetermined length over diameter (L/D) ratio and then operating the engine at certain predetermined values for the interacting parameters of spark gap location, volume percent of auxiliary chamber filled with said fuel-rich mixture, and percent of stoichiometric fuel in said fuel-rich mixture; with said predetermined values for said parameters having been predetermined relative to said L/D ratio.

Direct-injection spark-ignition engine

Abstract: A direct-injection spark-ignition engine including a governor for sensing the rotational speed of the engine, fuel injection pumps for injecting fuel at a rate which may be increased or decreased by a fuel control rack connected to the power shaft of the governor, fuel injection nozzles for directly injecting the fuel from the pumps into the respective engine cylinders, ignition plugs for igniting and burning the fuel charges injected from the nozzles by spark discharge, and suction air passages through which air flows toward the combustion chambers, characterized by throttle valves each of which is mounted within each suction air passage to open or close the same, and throttle control mechanisms each of which is connected to the throttle valve and the fuel control rack to open or close the valve in such a way that the valve opening is increased in proportion to an increase in the quantity of fuel injection.

Two-Stage Combustion for Low Emissions without Catalytic Convertors

Abstract: The concept of using two-stage combustion in a spark ignition engine has been tested in a single cylinder CFR engine. The engine was operated over an equivalence ratio range of 1.5 to 2.2 to evaluate the first stage of combustion. The product gas was analyzed for H/sub 2/, CO, CO/sub 2/, and hydrocarbons. An atmospheric burner was operated with gasoline over the same equivalence ratio range of 1.5 to 2.2, and the resulting product gases were then burned in the CFR engine to test the second stage of combustion. Emissions of NO/sub x/, HC and CO of 0.1, 0.1, and 5 gm/IHP-hr were measured respectively. The engine indicated efficiency for the two-stage mode was essentially the same as for the single-stage mode.