Patent ID: 7778763
Filing Date: 2010-08-17
Classification: F02D,Y02T

Abstract:
1. A fuel property determination system for a multi-cylinder internal combustion engine that sets fuel injection amounts into each of the cylinders during the engine starting process on the assumption that a heavy fuel will be injected, wherein the fuel property determination system allows a specific torque to be generated by combustion in a specific cylinder when a fuel with a specific property between those of the heaviest fuel and the lightest fuel is injected thereinto, determines that the property level of fuel to be injected into each cylinder during the engine starting process is in a level range at and around the specific property when the torque actually generated in the specific cylinder is in a range at and around the specific torque, determines that the property level is in a level range on the light fuel side of the level range at and around the specific property when the torque actually generated in the specific cylinder is higher than the range at and around the specific torque, determines that the property level is in a level range on the heavy fuel side of the level range at and around the specific property when the torque actually generated in the specific cylinder is lower than the range at and around the specific torque, decreases a fuel injection amount so that the specific torque is generated by combustion in the specific cylinder when the fuel with a specific property is injected thereinto, allows a specific torque to be generated by combustion in at least a second specific cylinder when the fuel with a specific property is injected thereinto without decreasing the fuel injection amount thereinto, determines that the property level of fuel to be injected into each cylinder during the engine starting process is in a level range at or around the specific property when the torque actually generated in the second specific cylinder is in a range at or around the specific torque, determines that the property level is in a level range on the light fuel side of the level range at or around the specific property when the torque actually generated in the second specific cylinder is higher than the range at or around the specific torque, determines that the property level is in a level range on the heavy fuel side of the level range at or around the specific property when the torque actually generated in the second specific cylinder is lower than the range at or around the specific torque, and determines, only when the fuel property level determined in the specific cylinder and the fuel property level determined in the second specific cylinder coincide with each other the coincident fuel property level as the property level of the fuel to be injected into each cylinder during the engine starting process.