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A methanol fueled, lean burn system has been developed to improve both specific fuel consumption and NOx emissions. A 1.6L four-cylinder engine with increased compression ratio has been used to develop this system. Three major components of the Toyota Lean Combustion System (T-LCS) have been applied: (1) A helical port with a swirl control valve (2) A lean mixture sensor (3) Timed, multi-point fuel injection. A 2250 lb. Inertia Weight test vehicle has been fitted with this engine, and fuel system materials have been modified. This methanol, lean burn system has improved the fuel economy by about 12% still satisfying the 1986 emission standards of the U.S.A. and Japan. Aldehyde emissions have also been evaluated.

The effects of methanol/cosolvent/gasoline blends on hot weather driveability are surveyed. Results show that startability after engine-off soak drastically deteriorates in an EFI vehicle. By observing the behavior of the fuel in the delivery pipe during hot-start testing and the injected fuel spray shape at high fuel temperature, the authors confirmed that the main cause of this malfunction was the vapor lock in the injector nozzle. The relationship between hot weather driveability and fuel properties is discussed. The gasoline volatility expression commonly used to indicate deterioration in hot weather driveability was found to underestimate the increase in volatility of blended fuels at higher temperatures. A suggestion is made for a modification to the expression to include the effects of methanol blending on volatility characteristics at high temperatures so that EFI vehicle hot-startability may be predicted.