Patent ID: 6227151
Filing Date: 2001-05-08
Classification: F02B,F02D,F02M,Y02T

Abstract:
A method of operating a gasoline internal combustion spark ignition engine, which comprises separating the gasoline fuel by boiling point into at least two fractions, and separately supplying the fuel fractions to the combustion chamber of the engine in such a manner as to achieve in each cylinder a two-zone stratification of the charge at the instant of spark when the engine is operating at low and medium loads, the two-zone stratification consisting of two contiguous mixture clouds, a first of the two clouds lying in the vicinity of the spark plug and containing a higher concentration of the higher boiling point fuel fraction than the second cloud lying at a distance from the spark plug, the average composition of the fuel and the fuel-to-air ratio in the said second cloud being such that the second cloud undergoes auto-ignition subsequent to the instant of spark ignition of the first cloud, the auto-ignition of the second cloud being brought about by the increased temperature and pressure resulting from the advancing flame front in the first cloud and the timing of the auto-ignition of the second cloud thereby occurring at a predetermined time delay after the instant of spark ignition of the first cloud.