Showing papers on "Spark-ignition engine published in 1982"

Flow in the piston-cylinder-ring crevices of a spark-ignition engine: effect on hydrocarbon emissions, efficiency and power

Abstract: Ecoulement dans la zone piston-cylindre-segments d'un moteur a allumage par etincelle. Influence sur les emissions d'hydrocarbures, le rendement et la puissance

Starter device for a multi-cylinder spark-ignition engine

Abstract: Multi-cylinder spark-ignition engines the combustion chambers of which are supplied with fuel by petrol injection have starter devices. Starter devices of this type are to be designed so that they have a low energy requirement, are of low weight, permit the use of accumulators with a low ampere-hour number and generate no unwanted starter noise. To this end it is proposed that a detector device should signal the respective piston state of the engine to a microprocessor which, when starting, causes a quantity of fuel necessary for combustion to be injected into and ignited in that cylinder of which the piston is in the working position, and thereafter fuel to be injected into that cylinder of which the piston will perform the next working stroke, followed by ignition as soon as the piston in question has reached the working position.

The effect of combustion chamber shape on the rate of combustion in a spark ignition engine

Abstract: Influence de la forme de la chambre de combustion sur le taux de combustion dans un moteur a allumage par etincelle

Thermal Loading of the Cylinder Head of a Spark-Ignition Engine

Abstract: The effects of operating parameters on the steady-state heat flux and surface temperature at several locations on the cylinder head of a single-cylinder spark-ignition engine were investigated. The local heat flux was found to be strongly affected by engine speed and volumetric efficiency. Air-fuel ratio and spark timing had comparatively smaller effects. Coolant temperature, in the range of this study (300-380 K), had no effect on the average heat flux. Both the heat flux and the surface temperature varied considerably with the location of measurement. Except at very rich mixtures, the average heat flux was found to vary as the 0.65 power of the rate of fuel consumption.

Alcohol fuels for highway vehicles

Abstract: While much progress has been achieved in both the production and utilization aspects, the ''perfect'' engine/fuel combination has yet to emerge. This article describes the current status of alcohol fuels utilization technology for spark ignition engine highway vehicles. Methanol, ethanol, methanol derivatives (ethers), and blends of each with gasoline are discussed. Alcohol fuels are currently receiving serious consideration as petroleum extenders and substitutes both for spark ignition (SI) and compression ignition (CI) powerplants. Alcohol fuels research is much further advanced in the SI engine area than it is for CL engines, the latter having begun to attract serious attention only recently. This paper is concerned with the SI engine only. Extensive property data for gasoline, diesel fuel, methanol, ethanol, and MTBE are compared with each other. Environmental considerations involved in the use of alcohol-based fuels are included. 43 refs.

Method for the automatic adjustment of the ignition initiation control time in an internal combustion engine

Abstract: A method is provided for the automatic control of the ignition time in a spark ignition engine or the injection time in a compression-ignition engine wherein at least one typical phenomenon of the running conditions of the engine, such as the occurrence of the peak pressure in the cylinder within a certain angular interval of the crankshaft, or the passage of the flame front through a reference position of the combustion chamber is detected, and the detected measurements have an aleatory character. This method comprises the determination of a statistical value representative of at least P validated measurements, of said phenomenon occurring during at most Q cycles, and the use of said statistical value to modify the control time of the combustion initiation so that said statistical value takes a predetermined value corresponding to the desired running conditions.

A Highly Efficient Alcohol Vapor Aspirating Spark–Ignition Engine with Heat Recovery

Abstract: The fuel properties of the lower alcohols indicate that both, straight methanol and ethanol are fundamentally unsuitable for utilization in the compression ignition process. In order to achieve the optimum possible benefit from the specific advantages of these alcohols, the alcohol-gas engine concept has been developed by Daimler-Benz. Due to partial recovery of the engine's waste heat by fuel vaporization and extreme lean burn capability, remarkable engine efficiencies are obtained. Design, performance, further development and installation of this system in prototype city buses are described.

Optimising the spark ignition pre-chamber geometry including spark plug configuration for minimum nox emissions and maximum efficiency

Abstract: Simulation studies of spark ignition engine combustion including the effects of cycle-by-cycle variability on emissions and thermal efficiency demonstrated that there exists a desirable regime of engine operation. This paper reports the achievement of these conditions in a single cylinder cfr engine through the use of a precombustion chamber. This engine was instrumented for flame mapping, combustion heat release and emissions analysis. Combustion rates could be varied by the adjustable geometry (volume and throat area) of the pre-chamber. The location of the spark electrodes and their configuration could also be changed. Experimental search through a multi-dimensional matrix of geometries, air-fuel ratios, spark timing, manifold pressure, engine speed and compression ratio demonstrated that 15 per cent improvement in relative thermal efficiency coupled with 70 per cent reduction in NOx could be simultaneously achieved. The design of the near optimal pre-chamber for this engine is reported. The location of the ignition source and the orientation of the spark electrodes proved to be a dominant variable. The traditional location of the spark gap at the closed end of the pre-chamber proved to be least satisfactory. (Author/TRRL)

Motorcycle with turbocharge type spark ignition engine

Abstract: PURPOSE:To furnish a compacted engine with high performance by arranging radiators for the engine and intercooler on the right and left side of the exhaust pipe, installing a baffle chamber at the outlet of the turbine, and by providing a resonance chamber at the suction gas outlet of the intercooler. CONSTITUTION:This motorcycle has a water cooled engine 1, an intercooler 6 and a turbocharger 7. Radiators 26, 27 for the engine and intercooler are installed on the right and left side of the exhaust pipe 13 arranged angular to each other in such a way as opening toward the front to smooth the flow of cooling wind behind the radiator. A baffle chamber 12 is provided between the outlet of turbine 10 and the exhaust pipe 13, and the exhaust pipe is posed downward for connection with this baffle chamber. Accordingly, the back pressure of the turbine will decrease and the exhaust energy to drive the compressor 18 can be utilized effectively. Further, a resonance chamber 20 is provided at the suction gas outlet of the intercooler 6 consolidated to increase the capacity of intercooler 6 and enhance the performance.

Effect of Di-t-Butyl Peroxide on the Lean Operating Limit of a Spark-Ignition Engine

Abstract: A study was conducted to determine whether the addition of di-t-butyl peroxide to unleaded gasoline would extend the lean operating limit of a spark-ignition engine. Tests were conducted with a single-cylinder, Cooperative Fuel Research engine. In these tests, the lean misfire limit equivalence ratio was extended by 6 and 10 percent with blends of 1 and 5 volume percent, respectively, of di-t-butyl peroxide and unleaded gasoline, compared to the value obtained with only unleaded-gasoline. It is hypothesized that the improved lean combustion was caused by the dissociation of di-t-butyl peroxide to tertiary butoxy radicals, which in turn reacted with the unleaded gasoline thus increasing the fuel oxidation rate.

Carburettor for a spark ignition engine

Abstract: Carburettor for a spark ignition engine having a nozzle needle which can be adjusted in an operation-dependent manner and having a pressure probe in the carburettor pipe. An engine speed measuring circuit (23) which evaluates gear pulses which are synchronous with the crank shaft rotation, provides a digital engine speed value for each rotation of the crank shaft. The technical problem of the invention consists in setting the nozzle needle as a function of the load state and/or working state of the internal combustion engine. The engine speed value is present on an input rail of an address memory (26) in which needle set values for the nozzle needle are stored. The measured value of the pressure probe (28) is present in digital form at selection inputs (27) of the address memory (26). A digital-to-analog converter (31) converts the digital needle set values, available at the output of the address memory as a function of the engine speed value and the pressure measuring value, into analog values. An engine (13) is coupled on its output shaft (12) to a sliding sheath (9) on which the nozzle needle (8) is seated. The output shaft (12) of the engine (13) is coupled via a spur wheel gear to a rotary potentiometer (17) which outputs an analog actual signal for the position of the nozzle needle (8). A comparator circuit (32) compares the output value of the rotary potentiometer as actual value and the analog needle set value and outputs a control signal for the engine.

Methane and Diesel Engines

Abstract: In other chapters you will read that diesel engines can be operated on gaseous fuels. Accordingly, I shall try to bias my presentation towards some features associated with such operation and emphasize the comparative aspects of operating diesel engines on methane relative to propane, hydrogen or ethylene because this is an issue that needs to be addressed.

Preignition detector for spark ignition engine

Abstract: PURPOSE:To perform accurate detection by removing a light noise by spark discharge, by providing an optical filter which permits only light having longer wavelength than near-infrared rays have to pass through it selectively. CONSTITUTION:Light generated in a combustion chamber is guided by a flash detection part 101 and its wavelength is selected by an optical filter 107. With wavelength characteristics of transmittivity of the filter 107, light of <=6,500Angstrom is occluded and light by spark discharge is cut to detect only a flash-signal by combustion. Combustion light from the optical guide part 102 of a detector 10 enters a photoelectric converter 18, where it is converted into a voltage signal. On the basis of an upper dead point signal from a crank angle detector 16, a preignition discriminating circuit 20 discriminates the occurrence of preignition from a time difference berween an ignition point signal from a gamma-time delay ignitor 15 and the signal of the photoelectric converter 18.

Feed method and device of injection fuel in spark-ignition engine

Abstract: PURPOSE:To promote vaporization of liquid fuel, by arranging the fuel injection timing at the end of an intake stroke in each cylinder CONSTITUTION:A built-in speed sensor 10 in a distributor consists of a rotor 12 and pick-up element 13 having crest parts 111-114 The crest part 111 is formed higher than the other crest parts, when this part passes through the pick-up element 13, a voltage signal of larger level is generated by the pick-up element 13 than at passing of the other crest parts The voltage signal is input to a waveform shaper circuit 14 and control circuit 15 The signal generated from the speed sensor 10 is input to the control circuit 15 as an engine speed signal and cylinder decision signal, simultaneously a generated signal from an air flow meter is input as an intake air quantity signal, then quantity of injection fuel is decided on the basis of the engine speed signal and the intake air quantity signal An output signal of the control device 15 shall be an output at the end of an intake stroke in a cylinder

Free-piston Stirling hydraulic engine and drive system for automobiles

Abstract: The calculated fuel economy for an automotive free piston Stirling hydraulic engine and drive system using a pneumatic accumulator with the fuel economy of both a conventional 1980 spark ignition engine in an X body class vehicle and the estimated fuel economy of a 1984 spark ignition vehicle system are compared. The results show that the free piston Stirling hydraulic system with a two speed transmission has a combined fuel economy nearly twice that of the 1980 spark ignition engine - 21.5 versus 10.9 km/liter (50.7 versus 25.6 mpg) under comparable conditions. The fuel economy improvement over the 1984 spark ignition engine was 81 percent. The fuel economy sensitivity of the Stirling hydraulic system to system weight, number of transmission shifts, accumulator pressure ratio and maximum pressure, auxiliary power requirements, braking energy recovery, and varying vehicle performance requirements are considered. An important finding is that a multispeed transmission is not required. The penalty for a single speed versus a two speed transmission is about a 12 percent drop in combined fuel economy to 19.0 km/liter (44.7 mpg). This is still a 60 percent improvement in combined fuel economy over the projected 1984 spark ignition vehicle.

Turbulent combustion rate in a spark ignition engine: some comparisons between model predictions and experiments

Abstract: A computer simulation model of the combustion process in a spark ignition engine is being developed for the investigation of flow field effects. The model is based on a two zone (burned and unburned gases) thermodynamic analysis of the combustion process that includes axisymmetric mean flow, uniform turbulence, and heat transfer. The turbulence is described by an averaged K-epsilon model which gives the bulk values of the turbulent kinetic energy and the dissipation rate in both the burned and unburned zones. Three experimental diagnostics were used in the study: the initial conditions for turbulence intensity necessary for the model were determined by laser Doppler velocimetry measurements made under motored conditions; the flame shape and location were found by laser shadowgraph photography; cylinder pressure measurements were recorded for both the average engine performance over many cycles, and for each individual cycle in which a photograph was taken. Comparisons between measurements and model predictions are presented for variations in engine speed and ignition location.

Detector for accidental fire of spark ignition engine

Abstract: PURPOSE:To assuredly eliminate the effect of spark ignition, etc. and to ensure the accurate discrimination for the generation of an ion current, by providing a switch to an i0n current detecting circuit and then closing the switch so as to cover the period of generation of the ion current. CONSTITUTION:A circuit I always applied the DC voltage of -300V to an ignition plug P under the operation of an engine; and an ion current detecting circuit II puts a capacitor C2 plus switches S and R2 in series between the middle point B of a resistance 1 and a diode D3, and gives the earth between the C2 and S via a D4. The switch S closes the circuit for a prescribed period of time through an accidental fire discriminating circuit III and by means of the plug P in the lapse of a certain time set at the end of the spark discharge. The closing time of S is set to that it assuredly covers the time of generation of the ion current due to ignition.

Spark-ignition engine with sub-chamber

Abstract: PURPOSE:To reduce the amount of unburned HC in the main combustion chamber by providing a spark plug in a sub-chamber and by forming ajet nozzle connecting the main chamber and the sub-chamber in a manner that it is pointed in the circumferential direction of the main chamber so that the jet of flame from the sub-chamber promotes the combustion in the neighborhood of the cylinder wall. CONSTITUTION:To a cylinder head 3 is fitted a sub-chamber 6 in an eccentric position, therein is formed a sub-chamber area 7. A jet nozzle 8 connecting the main chamber 5 and sub-chamber 7 is formed in a manner that it is pointed in the circumferential direction of a cylinder 2 and a spark plug 9 is placed in the sub-chamber. when the spark plug 9 in the sub-chamber 7 is fired approximately at the same time or a little later than the ignition in the main chamber, the air-fuel mixture in the sub-chamber 7 burns to turn into high-temperature and high-pressure gases, which are forced into the main chamber 5 through the jet nozzle 8. Thus the jet stream of gases proceed at a very high speed and collide with the wall of the main chamber 5 to cause violent disturbances to the quenching layer so that it is separated from the wall to get mixed with the high-temperature burned gases. this makes it possible to achieve better combustion of the air-fuel mixture, thus so much reducing the amount of unburned HC.

A thermal analysis of a spark ignition engine piston

Abstract: Today, internal combustion engines are expected to be light and high-powered. Because of this, the thermal loading for engine components, especially pistons, has become very severe. Prediction of temperature distribution and subsequent stress on piston under operation is of utmost importance in ensuring better design reliability. Since the development of structural analysis by means of finite element method (fem), research has been carried out and calculations made on temperature distributions in engine pistons. In these studies, axisymmetric or one quarter models were employed. In order to obtain the heat transfer coefficient, either conventional formulas were adapted or parametric study was undertaken. Through the many examinations on piston temperature it was shown that the temperature distributions were not symmetric with respect to the plane of the piston pin. It is considered that an axisymmetric or a one quarter model is insufficient. The gas-side heat transfer coefficients vary with locations so that the formulas were not employed. Also it is inconsistent to treat the local heat transfer coefficients only as parameters. The same statement is true for the lands, ring grooves and skirt. In this study, a one half model was employed for the structural model and local heat transfer coefficients of the actual temperature and heat flux measurements were used on the objective engine. Heat- conduction calculations were made for the piston. The calculated values corresponded excellently with the experimental values. (Author/TRRL)

The "alvar" engine concept; a variable compression ratio spark ignition engine

Abstract: Improvements in gasoline fuelled Otto-cycle engines are expected to result from increased compression ratio. Problems that will have to be solved are those involving increased friction losses and other problems related to fuel octane ratings. In this report one concept is presented that shows good promise of an essential decrease in the fuel consumption for Otto-cycle engines, namely the Alvar-engine concept utilizing a variable geometry of the combustion chamber. The concept has shown in test to operate at part load with optimal compression ratio without the problems of uncontrolled combustion. It has been verified that optimum fuel economy may be reached by increasing the compression ratio at part load, and by means of a continuously moving auxiliary piston the problems of coking and scorching of the auxiliary piston is removed. It is recognised that there is a considerable amount of work still to be performed before the engine concept is ready for production, but it is considered that the concept, utilizing further development within the field of optimal control via electronics of the variables fuel injection, spark timing, and air to fuel ratio, the fuel consumption of passengers cars and light trucks can be substantially reduced within the fundamental existing engine concepts. (Author/TRRL)

Temperature measurements of combustion gas in a prechamber spark ignition engine

Abstract: An infrared absorption-emission pyrometer is used to measure instantaneous gas temperatures at several stations in order to understand the mechanisms of the combustion process in a prechamber spark ignition engine. Gas temperature diagrams are obtained with both the air-fuel ratio and torch nozzle diameter as parameters. It is disclosed that the cyclic fluctuations in the combustion process, temperature-rise in the auxiliary chamber and flame propagation in the main chamber are influenced considerably by such factors as air-fuel ratio, and torch-nozzle diameter. The optical pyrometer is also employed to determine the monochromatic emissivity which is needed in the use of a monochromatic radiation pyrometry.

Aldehyde emissions from an ethanol petrol fuelled spark ignition engine

Abstract: Emissions of aldehydes and other species were compared from an automobile engine fuelled on petrol and a 20 per cent ethanol - 80 per cent petrol blend. Measurements were carried out over a range of engine load and speed to produce an emission map. Aldehyde emission increased sixfold with the alcohol fuel. The aldehyde levels were found to be a constant fraction of hydrocarbon levels over the operating map (a).

Direct cylinder injection type spark ignition engine

Abstract: PURPOSE:To improve an efficiency of combustion due to a layer combustion by forming a cavity of a small capacity inside a cylinder head and sending a mixture of air and fuel which is produced by injecting the fuel into the cavity to a main combustion chamber for ignition and burning therein. CONSTITUTION:A cavity for a main combustion chamber 4 is formed in an upper area of a reciprocating piston 3 which makes a slidable friction inside a cylinder 2 and a sub-piston 5 which is projected upright from the piston head is formed at one site of the rim of the main combustion chamber 4. An adapter 8 which contains a cavity 7 opening toward the piston 3 is driven into a cylinder head 6 at a position opposed to the sub-piston 5 and equipped with a fuel injection valve 9 therein. A longitudinal communication groove 11 is engraved in the side face of the sub-piston 5 of the piston 3 on the side of the main combustion chamber 4 so that a mixture in the cavity 7 is squeezed therethrough into the main combustion chamber 5 when the sub-piston 5 is inserted into the cavity 7 in association with an elevation of the piston 3 nearly up to its top dead center on a compression stroke.