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It has been demonstrated that the in-cylinder turbulence of a 4 valve engine with a swirl control valve (SCV) is enhanced by inclined swirl. This paper examines the effects on turbulence of varying swirl inclination angle defined as the inverse tangent of the vertical component of total angular momentum divided by the horizontal component. Experiments were conducted on a 4-valve single cylinder engine with SCV using a backward-scatter LDV and BSA (Burst Spectrum Analyzer). The results show that although total angular momentum is greatest with horizontal swirl, turbulence intensity measured in the center of the combustion chamber attains a peak value when the swirl inclination angle is between 30 and 45 degrees from the cylinder axis under the same air flow rate.

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.