Two series of tests on a 4-cylinder, 4-stroke cycle, carburetor fueled gasoline engine were performed to enhance the understanding of the I.C. engine combustion and fuel distribution characteristics.
The first was to understand the relation between engine performance and combustion behavior affected by increased swirl. Simple swirl vanes were constructed and installed near every inlet ports.
It was confirmed by preliminary bench tests that the swirl strength was substantially increased by the swirl vane with only marginal loss in air mass flow. Engine tests were followed to show that substantially improvements in engine performance such as cyclic variation, torque, imep, bsfc and emission were materialized by swirl vane particularly in low and medium rpm and/or torque conditions.
Another venture was attempted to improve the fuel distribution among cylinders by means of a tube extending the riser length. An overall trend of improvement in fuel distribution was realized through out most of engine operating ranges with occasional degradations.
