Spark Ignition Internal Combustion Engine Research Articles

Quench Layer Contribution to Exhaust Hydrocarbons from a Spark-Ignited Engine

INTRODUCTION Hydrocarbons remaining in a wall quench layer have been proposed as a major source of hydrocarbon emissions in spark-ignited internal combustion engines (Daniel and Wentworth, 1962). Additional experiments using wall mounted sampling valves were subsequently carried out by Daniel (1967), Muller and von Watzdorf (1968), Weiss et al. (1979), and Henningsen and Qvale (1980). Our paper presents the results of an experimental study of the quench layer also using a wall mounted sampling valve. The valve was electrohydraulically actuated and had uniquely small leakage and crevice characteristics. Our results do not support the contention that the wall quench layer is a major source of exhaust emissions. Hydrocarbons from other sources, as yet not quantified, such as those emitted from ring crevices, deposits or oil films appear to be likely contributors to exhaust hydrocarbons (Wentworth, 1971; Haskell and Legate, 1972; and Kaiser et al., 1980).

Simple device for reduction of pollution from motor vehicles

A simple retrofit device was developed to reduce the exhaust emission from a spark ignition internal combustion engine, and complies with the U. S. Federal 1973 requirements and the current European maximum emission levels. The device aims at improving the vaporization and atomization of the air/fuel mixture fed to the engine by incorporating a second venturi and an air bleed under the existing carburetor.

Paper 7: Accuracy of and Representative Results Obtained with an Infra-Red Pyrometer Measuring Compression Temperatures

In a spark-ignited internal combustion engine there are two zones of interest ( a) the burnt mixture and ( b) the unburnt mixture. Of interest to the authors and to many of their colleagues are the pre-reactions which occur in the unburnt zone. To follow the extent of these pre-reactions both the pressure and the temperature of the unburnt mixture are required. Pressure transducers can be obtained from many commercial establishments, but a temperature pyrometer that can follow the temperature of the unburnt mixture is not commercially available. The current technique uses the absorption, emission characteristic of the water vapour in the cylinder. The use of water vapour as the sensing element is desirable since water vapour is normally in the air which the internal combustion (i.c.) engine breathes. Radiation of a known intensity (known black-body temperature) is passed through the engine, through a band pass filter (H2O water vapour band at 2.6 μ) to an infra-red detector. The output from the detector, after amplification, is fed to a cathode-ray oscilloscope. By suitable means, it is possible to compare the undisturbed radiation from the black body with the black-body radiation after it has experienced absorption emission events during the compression process. The reversal point can be visually observed on the oscillogram. At this reversal point the temperature of the gas and the black body are equal and the crank angle at which this occurs can be determined. Other temperatures and crank angles at which reversal occurs can be observed to obtain the unburnt mixture temperature versus crank angle curve. The authors' experiences with different infra-red detectors and other temperature-measuring techniques, as well as comparison between the velocity of sound method and the infra-red technique, are discussed. Data obtained with the instrument are presented.