Patent ID: 7077105
Filing Date: 2006-07-18
Classification: F02D,F02P,Y02T

Abstract:
1. A spark ignition internal combustion engine, comprising: a fuel mixture portion that mixes a high-octane fuel and a low-octane fuel based on a variable mixing proportion, and supplies a mixed fuel into a combustion chamber, a first mixing proportion adjusting portion that sets a standard octane number in accordance with an operation state of the spark ignition internal combustion engine, adjusts a mixing proportion between the high-octane fuel and the low-octane fuel so as to achieve the standard octane number, and uses the adjusted mixing proportion as a first mixing proportion; a reference ignition timing setting portion that sets a reference ignition timing corresponding to the standard octane number a knocking measurement portion that measures a state of occurrence of knocking in an operation state where fuel is injected based on the first mixing proportion and ignition is performed at the reference iginition timing a deviation determination portion that determines a deviation value between an actual mixing proportion between the high-octane fuel and the low-octane fuel really supplied into the combustion chamber and the first mixing proportion, the deviation value being set based on the measured state of occurrence of knocking; and a second mixing proportion estimation portion that estimates a mixing proportion between the high-octane fuel and the low-octane fuel based on the deviation value, and uses the estimated mixing proportion as a second mixing proportion.