Patent ID: 9611827
Date: 2017-04-04
CPC Classifications: F02P,F23Q,G01L,G01M

Claim:
1. An internal combustion engine comprising: an engine body having a plurality of cylinders; a combustion pressure sensor incorporated glow plug mounted to at least one of the plurality of cylinders, comprising a first heater which generates heat through energization, and a pressure sensor for detecting combustion pressure of the respective cylinder; a first electricity supply cable including a first electricity supply line for supplying electricity from an external power supply to the first heater; a sensor nonincorporated glow plug mounted to each of the remaining cylinders to which the combustion pressure sensor incorporated glow plug is not mounted, comprising a second heater without a pressure sensor, which generates heat through energization; and a second electricity supply cable including a second electricity supply line for supplying electricity from the external power supply to the second heater; wherein resistance of the second electricity supply line is greater than resistance of the first electricity supply line; wherein, defining a first plug regression line as a first plug voltage vs. temperature characteristic indicative of a relation, within a temperature range of 950° C. to 1,350° C., between a first plug voltage applied to the combustion pressure sensor incorporated glow plug and a first heater temperature indicative of a temperature of heat generated by the first heater, defining a second plug regression line as a second plug voltage vs. temperature characteristic indicative of a relation, within the temperature range, between a second plug voltage applied to the sensor nonincorporated glow plug and a second heater temperature indicative of a temperature of heat generated by the second heater, defining a first voltage as the first plug voltage at which the first heater temperature becomes a predetermined temperature within the temperature range on the first plug regression line, defining a second voltage as the second plug voltage at which the second heater temperature becomes the same predetermined temperature on the second plug regression line, and defining a first-second plug voltage difference as a difference at the predetermined temperature between the first voltage and the second voltage, the first plug regression line and the second plug regression line are in such a relation that, at any predetermined temperature within the temperature range, the second voltage is lower than the first voltage; and wherein, defining a first section regression line as a first section voltage vs. temperature characteristic indicative of a relation, within the temperature range, between a first section voltage applied to a first section comprising the combustion pressure sensor incorporated glow plug and the first electricity supply cable, and the first heater temperature, defining a second section regression line as a second section voltage vs. temperature characteristic indicative of a relation, within the temperature range, between a second section voltage applied to a second section comprising the sensor nonincorporated glow plug and the second electricity supply cable, and the second heater temperature, defining a third voltage as the first section voltage at which the first heater temperature becomes the predetermined temperature on the first section regression line, defining a fourth voltage as the second section voltage at which the second heater temperature becomes the same predetermined temperature on the second section regression line, and defining an overall voltage deviation as an absolute value of a difference at the predetermined temperature between the third voltage and the fourth voltage, the first section regression line and the second section regression line are in such a relation that, at any predetermined temperature within the temperature range, the overall voltage deviation is smaller than the first-second plug voltage difference.