Combustion state parameter calculation method for internal combustion engine

Patent metadata

Field	Value
Publication number	US-2016146703-A1
Application number	US-201514950183-A
Country	US
Kind code	A1
Filing date	Nov 24, 2015
Priority date	Nov 25, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A combustion state parameter calculation method for an internal combustion engine, which is capable of continuously calculating a combustion state parameter while properly maintaining the accuracy of the calculated parameter even when part of in-cylinder pressure sensors is in failure. In the combustion state parameter calculation method, as a combustion state parameter, a first combustion state parameter dependent on the magnitude of in-cylinder pressure is calculated based on a detection value from an in-cylinder pressure sensor, on a cylinder-by-cylinder basis. When it is determined that a characteristic abnormality failure in which the magnitude of the detection value deviates from the actual in-cylinder pressure has occurred in part of the in-cylinder pressure sensors and has not occurred in the other in-cylinder pressure sensors, the first combustion state parameter of a failure-determined cylinder is calculated based on the detection value from the other in-cylinder pressure sensors.

First claim

What is claimed is:

1 . A combustion state parameter calculation method for an internal combustion engine, which calculates, based on detection values from a plurality of in-cylinder pressure sensors provided in at least two cylinders of the engine, each for detecting in-cylinder pressure which is pressure in a cylinder associated therewith, a combustion state parameter indicative of a combustion state in the cylinder, comprising:
a first combustion state parameter-calculating step of calculating, as the combustion state parameter, a first combustion state parameter dependent on the magnitude of the in-cylinder pressure, based on the detection value from the in-cylinder pressure sensor, on a cylinder-by-cylinder basis; and a failure determining step of determining whether or not a characteristic abnormality failure in which the magnitude of the detection value from the in-cylinder pressure sensor deviates from an actual in-cylinder pressure has occurred, on an in-cylinder pressure sensor-by-in-cylinder pressure sensor basis, wherein when it is determined that the characteristic abnormality failure has occurred in at least one of the in-cylinder pressure sensors, and has not occurred in at least one of the other of the in-cylinder pressure sensors, said first combustion state parameter-calculating step calculates the first combustion state parameter of a cylinder provided with the at least one of the in-cylinder pressure sensors, based on the detection value from the at least one of the other of the in-cylinder pressure sensors.

2 . The combustion state parameter calculation method according to claim 1 , wherein the in-cylinder pressure sensor is provided in each of all cylinders of the engine and
wherein the first combustion state parameter is a torque parameter indicative of a torque which is generated by combustion in the cylinder, the combustion state parameter calculation method further comprising a total torque parameter-calculating step of calculating a sum of the torque parameters of all of the cylinders as a total torque parameter indicative of a total torque output from the engine.

3 . The combustion state parameter calculation method according to claim 1 , further comprising a hysteresis amount-calculating step of calculating a hysteresis amount indicative of the magnitude of deviation of the detection value from the in-cylinder pressure sensor from the actual in-cylinder pressure, and
wherein said failure determining step determines, when the calculated hysteresis amount is larger than a predetermined value, that the characteristic abnormality failure has occurred in the in-cylinder pressure sensor.

4 . The combustion state parameter calculation method according to claim 2 , further comprising a hysteresis amount-calculating step of calculating a hysteresis amount indicative of the magnitude of deviation of the detection value from the in-cylinder pressure sensor from the actual in-cylinder pressure, and
wherein said failure determining step determines, when the calculated hysteresis amount is larger than a predetermined value, that the characteristic abnormality failure has occurred in the in-cylinder pressure sensor.

5 . A combustion state parameter calculation method for an internal combustion engine, which calculates, based on detection values from a plurality of in-cylinder pressure sensors provided in at least two cylinders of the engine, each for detecting in-cylinder pressure which is pressure in a cylinder associated therewith, a combustion state parameter indicative of a combustion state in the cylinder, comprising:
a second combustion state parameter-calculating step of calculating, as the combustion state parameter, a second combustion state parameter dependent on a state of change in the in-cylinder pressure with respect to a crank angle of the engine and expressed by the crank angle, based on the detection value from the in-cylinder pressure sensor, on a cylinder-by-cylinder basis; and a failure determining step of determining whether or not a characteristic abnormality failure in which the magnitude of the detection value from the in-cylinder pressure sensor deviates from an actual in-cylinder pressure has occurred, on an in-cylinder pressure sensor-by-in-cylinder pressure sensor basis, wherein even when it is determined that the characteristic abnormality failure has occurred in at least one of the in-cylinder pressure sensors, said second combustion state parameter-calculating step calculates the second combustion state parameter of a cylinder provided with the at least one of the in-cylinder pressure sensors, based on the detection value from the at least one of the in-cylinder pressure sensors.

6 . A combustion state parameter calculation method for an internal combustion engine, which calculates, based on detection values from a plurality of in-cylinder pressure sensors provided in at least two cylinders of the engine, each for detecting in-cylinder pressure which is pressure in a cylinder associated therewith, a combustion state parameter indicative of a combustion state in the cylinder, comprising:
a combustion state parameter-calculating step of calculating, as the combustion state parameter, a plurality of types of combustion state parameters including a first combustion state parameter dependent on the magnitude of the in-cylinder pressure and a second combustion state parameter dependent on a state of change in the in-cylinder pressure with respect to a crank angle of the engine and expressed by the crank angle, based on the detection value from the in-cylinder pressure sensor, on a cylinder-by-cylinder basis; and a failure determining step of determining whether or not a characteristic abnormality failure in which the magnitude of the detection value from the in-cylinder pressure sensor deviates from an actual in-cylinder pressure has occurred, on an in-cylinder pressure sensor-by-in-cylinder pressure sensor basis, wherein when it is determined that the characteristic abnormality failure has occurred in at least one of the in-cylinder pressure sensors, and has not occurred in at least one of the other of the in-cylinder pressure sensors, said combustion state parameter-calculating step selects, when calculating the combustion state parameter of a cylinder provided with the at least one of the in-cylinder pressure sensors, the detection value from the at least one of the in-cylinder pressure sensors or the detection value from the at least one of the other of the in-cylinder pressure sensors, according to the type of the combustion state parameter.

7 . The combustion state parameter calculation method according to claim 5 , wherein said failure determining step is configured to determine, in addition to whether or not the characteristic abnormality failure has occurred, whether or not a fixed output failure has occurred in which the detection value from the in-cylinder pressure sensor does not change in response to a change in the actual in-cylinder pressure, and
the combustion state parameter calculation method further comprising a calculation inhibiting step of inhibiting, when it is determined that the fixed output failure has occurred in the at least one of the in-cylinder pressure sensors, calculation of the second combustion state parameter based on the detection value from the at least one of the in-cylinder pressure sensors.

8 . The combustion state parameter calculation method according to claim 6 , wherein said failure determining step is configured to determine, in addition to whether or not the characteristic abnormality failure has occurred, whether or not a fixed output failure has occurred in which the detection value from the in-cylinder pressure sensor does not change in response to a chan

Assignees

• Keihin Corp
• Honda Motor Co Ltd

Inventors

• Akazaki Shusuke
• Inoue Taisuke
• Saito Shunichi

Classifications

• F02D41/123

  the fuel injection being cut-off · CPC title

• F02D41/222

  relating to the failure of sensors or parameter detection devices · CPC title

• F02D35/023

  by determining the cylinder pressure · CPC title

• F02D41/009

  using means for generating position or synchronisation signals · CPC title

• F02D37/02

  one of the functions being ignition · CPC title