Showing papers on "Spark-ignition engine published in 1993"

Methanol as a fuel for spark ignition engines: a review and analysis

Abstract: A review and analysis of recent literature data on the use of methanol as an alternative fuel for internal combustion engines have been performed. The properties of methanol have been analysed from...

Fuel injection timing controller of spark ignition engine provided with supercharger

Abstract: PURPOSE: To prevent reduction in engine torque, degradation of fuel consumption ratio, increase in cost, and air pollution, etc., by minimizing the blowby of unburnt mixture to an exhaust port. CONSTITUTION: Under a drive condition where a cam position sensor 15 for detecting the opening/closing timing of an intake valve 9, pressure sensors 22, 24 for detecting intake pressure and exhaust pressure, and a valve timing control means 14 are operated while the intake pressure is higher than the exhaust valve, fuel injection timing is controlled by a fuel injection controller 13, which is included in and forms a fuel injection timing controller, so that a mixture reaches an intake port 5a after a valve overlap period (a period in which the intake valve 9 and an exhaust valve 10 are opened simultaneously) is completed. Even when the intake pressure exceeds the exhaust pressure during the valve overlap period, since the blended gas is fed into a cylinder 2 at a point when the valve overlap period is completed, the blowby of unburnt mixture to an exhaust port 6a can be minimized. COPYRIGHT: (C)1995,JPO

Determining fuel transfer characteristics for mixture control during transient operation

Abstract: This paper investigates the fuel transfer characteristics of the intake port of a fuel-injected spark ignition engine. These characteristics were examined for engine warm-up conditions, following cold starts at temperatures down to -30 degrees Celsius, and extending to fully warm states. The engine was cooled down to soak temperature, by circulating an antifreeze/water coolant mixture from a chiller tank through three parallel paths. During engine running, the coolant system was configured as in a vehicle, with a heat exchanger replacing the vehicle radiator. The general form of a test sequence was: (1) cold-soaking to the desired initial temperature; (2) engine starting; (3) stabilise load, speed, and mixture supply air-fuel ratio (AFR) as quickly as possible; and (4) performance of a sequence of tests in a repeating pattern, where each test disturbs the engine operating state and records the AFR response, as indicated by a UEGO sensor exposed to the exhaust gas stream. The interpretation of signal characteristics and the model-fitting procedure are described. Some illustrative results are given for: (1) typical values of time constant and fraction of fuel delivered to the intake system; and (2) compensated transient tests. For the covering abstract see IRRD 873243.

Analysis of the Effect of Inlet Valve Disablement on Swirl, Combustion and Emissions in a Spark Ignition Engine

Abstract: A four-valve spark ignition engine combustion system has been tested with normal valve operation and with each inlet valve disabled in turn A steady flow air rig has been used to establish the flow, barrel swirl and axial swirl characteristics The combustion performance has been evaluated at five operating points, to determine the effect of the increased swirl with inlet valve disablement The tests showed that the combustion was faster, with a lower level of cycle-by-cycle variation in combustion; the peak cylinder pressures also rose slightly and occurred closer to top dead centre (TDC) A computer model has been used to investigate the effect of faster burn on the trade-off between engine output, efficiency and nitrogen oxide emissions It is concluded that a faster burn, with an ignition timing retarded to give the baseline output, should lead to a reduction in nitrogen oxide emissions This is confirmed by a modelling exercise, which also indicated that using exhaust gas recirculation (EGR) should

High-speed spectral infrared imaging of spark ignition engine combustion. (Reannouncement with new availability information)

Abstract: In-cylinder flame propagation and its impact on thermal characteristics of the combustion chamber were studied by using a new high-speed spectral infrared imaging system. In this work, successive spectral IR images of combustion chamber events were captured while varying several parameters, including fuel/air, spark timing, speed, and warming-up period. Some investigation of cyclic variation, knock, and high-temperature components during the non-combustion period was also conducted. It was found that the spectral images obtained in both short and long wavelength bands exhibited unique pieces of in-cylinder information, i.e., (qualitative) distributions of temperature and combustion products, respectively. During the combustion period, the temperature of early-formed combustion products continued to increase while the flame front temperature, e.g. near the end gas zone, remained relatively low. The exhaust valve emitted strong radiation starting from the early stage of the combustion period. The spark plug emitted the strongest radiation during the non-combustion period. Considerable cyclic variation in growth of the flame front and completion of the reaction was observable. The radiation from both spectral bands became stronger as the engine warm-up period in While operating the engine with the addition of n-heptane in the intake to produce knock, we captured spectral IR images of themore » end gas right before it was abruptly consumed. The combustion products that were formed in the end-gas volume upon knock, showed no evidence of higher temperature than other zones in the combustion chamber.... Spectral infrared imaging, High-speed, Digital data, Instantaneous distribution, Spark ignition combustion.« less

Modelling infrared radiation from the combustion products in a spark ignition engine

Abstract: Application of the engine CFD code KIVA II with the inclusion of the SHELL model for autoiginition chemistry, and the discrete transfer radiation heat transfer model, has enabled the technically important problem of non luminous radiation from the major emitting species CO\d2 and H\d2O in the combustion products within the cylinder of a spark ignition engine to be considered as a combustion diagnostic aid, and also as a method of controlling individual cylinder Air/Fuel ratio. Results from a parametric study using CFD have been found to corroborate the experimental findings of other workers over a range of operating conditions including knock.

Investigations on a spark-ignited engine using two-dimensional laser-induced fluorescence

Abstract: The method of laser-induced fluorescence (LIF) was applied to a modified industrial two-stroke engine with a single cylinder and spark ignition. Together, the disc-shaped combustion chamber and the low clearance height of the piston ensure mainly two-dimensional flame propagation. Formaldehyde is used as a natural tracer species for detecting and studying exothermic centres (so-called “hot spots”) in the end gas. The latter contain a larger amount of formaldehyde than the enclosing end gas due to the slightly higher temperatures. To obtain two-dimensional excitation of the formaldehyde a laser light sheet enters from sideways through a ring-shaped quartz window. The fluorescence is detected via a full-size top window by means of an ultrashort-exposure ICCD-camera, and the frames are stored in a PC. Here, frames are presented which show 2D-LIF of formaldehyde in non-knocking as well as in knocking cycles.

Lean-Burning Characteristics of a Gas-Fueled Spark-Ignition Engine.

Abstract: The lean-burning characteristics of a spark-ignition engine homogeneously fueled with natural gas and propane are studied. It was shown that a higher swirl in a deep-bowl chamber significantly suppresses the cycle-to-cycle variation in peak pressure. There is a "window" of the equivalence ratio in which a very low concentration of oxides of nitrogen and an allowable degree of variation can be achieved over a range of loads, provided the ignition timing is correctly regulated with the operating conditions. Based on the test results, it is possible to establish a lean-burning gas engine without the supplementary treatments of a three-way catalyst or exhaust gas recirculation as an alternative to the diesel engine.

Two-Dimensional Measurements of the Mixture Concentration in the Combustion Chamber of a Spark Ignition Engine : Effects of Fuel Injection Conditions and Intake Flow

Abstract: An experimental study was made of the two-dimensional measurements of the mixture concentration distributions in the combustion chamber of a propane-fueled SI (spark ingnition) engine with laser-sheet-induced Rayleigh scattering. A commercial engine was modified to introduce YAG laser sheet light into the combustion chamber. The scattered light from the measuring plane was allowed to transmit the optical glass window installed on the extended piston and captured with a charge-coupled-device camera fitted with a gated double-microchannel-plate image intensifier by lens coupling, and the resulting images were digitized in a computer. The effects of several engine-operating parameters, including the fuel injection conditions and the intake air flow, were investigated.

Correlation between cycle-resolved 2D velocity measurements and early combustion in a spark ignition engine

Abstract: The objective of this paper is to investigate how the low and high frequency parts of the flow at different locations close to the spark plug influence the early combustion at individual cycles in a SI-engine. 2-components cycle-resolved laser doppler velocimetry (LDV) measurements have been done both inside the spark gap, and around the spark tip to extract velocity information. The pressure in the cylinder was measured with a piezo-electric transducer connected to an A/D-card in a standard PC. The velocity information was filtered to get 'mean velocity' and 'turbulence'. The pressure signal was used in an one-zone heat-release model to get different levels of mass fraction burned etc. The results show a significant correlation between the velocity and the early combustion when the velocity was measured close to the spark plug tip. The correlation decreased when the velocity was measured at some distance from the electrodes for both a pancake and a high squish combustion chamber. The correlation between the velocity close to the spark plug and the early flame development showed no dependence on the air-fuel ratio.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.