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Engine cold starting tests have been conducted in a laboratory cold chamber to compare the performance of three 10% methanol/90% gasoline blends with that of Indolene. The blends had different Reid Vapour Pressures and tests were conducted over a wide range of fuel/air ratios at temperatures as low as −45°C. It was found that all M10 blends tested had poorer starting performance than Indolene at cold temperatures, including those of nominally higher volatility. Cold starting did not correlate to Reid Vapour Pressure even when comparing two oxygenated fuels. Graphs are presented showing minimum cold starting temperature as a function of fuel-air equivalence ratio.

The present cold starting performance of methanol fuelled spark ignition engines is poor compared to their gasoline counterparts. Apparatus has been developed to cold soak a small engine to temperatures as low as −65°C. Tests have been conducted using methanol, Indolene and sample of commercial gasoline of depressed volatility. Data are provided showing the effect of fuel-air ratio on minimum starting temperature for the three fuels. Methanol failed to start at temperatures below about 0°C whereas the Indolene started easily to below −45°C. Reid Vapour Pressure is shown to be ineffective as a predictor of cold starting performance for methanol.

The temperature and pressure of the charge, reached at the end of the compression stroke when an engine is cranked for starting, decide whether it will start and attain selfsustained running. These, in turn, are affected by the crevice volume in, and the blowby from, the engine, particularly at cold ambient temperatures and low cranking speeds. This paper presents a model to estimate these effects. Tentative values are proposed for the parameters that appear in the model based on experiments performed on small engines motored in a cold chamber. The model can be incorporated in engine cycle simulation programs to allow for crevice and blowby effects. It is impossible to prevent gas leakage entirely from an operating reciprocating engine. Gas may leak at the valves, the cylinder head gasket, the spark plug gasket, the injector gasket and the piston rings. The gas that leaks from the cylinder past the piston rings into the crankcase is termed “blowby”.

This study describes the design and proof-of-concept testing of a system which has enabled sub-zero cold starting of a port-injected V6 engine fuelled with M100. At -30°C, the engine could reach running speed about 5s after the beginning of cranking. At a given temperature, starts were achieved using a fraction of the mixture enrichment normally required for the more volatile M85 fuels. During cold start cranking, firing is achieved using a high energy plasma jet ignition system. The achievement of stable idling following first fire is made possible through the use of an Exhaust Charged Cycle (ECC) camshaft design. The ECC camshaft promptly recirculates hot exhaust products, unburnt methanol and partial combustion products back into the cylinder to enhance combustion. The combined plasma jet/ECC system demonstrated exceptionally good combustion stability during fast idle following sub-zero cold starts.

This paper describes the vehicle implementation and cold start calibration of a neat methanol (M100) fuelled port injected engine equipped with plasma jet ignition and prompt exhaust gas recirculation. Test results are presented in which the influence of various factors on fuel enrichment requirements were studied with the aim of identifying strategies to reduce enrichment and lower start-up emissions. Vehicle cold starting has been demonstrated down to -30°C and studied in detail circa -20°C. Reductions in start-up CO emissions at -7°C have been achieved by means of early closed loop fuel control. Experimental results are also presented which indicate that the potential exists to reduce start-up hydrocarbon emissions at 25°C when appropriate calibration strategies are employed.