Heat generation rate waveform calculation device of internal combustion engine and method for calculating heat generation rate waveform

Patent metadata

Field	Value
Publication number	US-2017184019-A1
Application number	US-201515305033-A
Country	US
Kind code	A1
Filing date	Feb 9, 2015
Priority date	Apr 22, 2014
Publication date	Jun 29, 2017
Grant date	—

Abstract

A first-half combustion period, for example, is estimated/evaluated, with a required accuracy, more simply than the conventional art, while reducing man-hours to produce a heat generation rate waveform of an internal combustion engine. Within a combustion period of an air-fuel mixture, a period from an ignition time FA to a heat generation rate maximum time dQpeakA where the heat generation rate is maximum is defined as the first-half combustion period a that is one of characteristic values of the heat generation rate waveform. The first-half combustion period a is estimated based on an in-cylinder volume at the heat generation rate maximum time, and furthermore by being corrected using an exponential function of the engine rotation speed with a value depending on a tumble ratio as exponent. Thus, the heat generation rate waveform is produced using the estimated first-half combustion period a.

First claim

1 . A heat generation rate waveform calculation device of an internal combustion engine, the device being configured to calculate a heat generation rate waveform of a spark-ignition internal combustion engine,
wherein, within a combustion period of an air-fuel mixture, a period from an ignition time to a heat generation rate maximum time where a heat generation rate is maximum is defined as a first-half combustion period that is one of characteristic values of the heat generation rate waveform, wherein the first-half combustion period is estimated based on a physical quantity at the heat generation rate maximum time, so that the heat generation rate waveform is calculated using the estimated first-half combustion period, and wherein the first-half combustion period is estimated as a value not affected by at least one of an engine load rate, an air-fuel ratio, an exhaust gas recirculation (EGR) rate and an oil-water temperature.

2 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 1 ,
wherein the first-half combustion period is calculated based on an in-cylinder volume at the heat generation rate maximum time.

3 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 2 ,
wherein the first-half combustion period is calculated by being multiplied by a correction coefficient based on an engine rotation speed.

4 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 3 ,
wherein the correction coefficient based on the engine rotation speed is an exponential function of the engine rotation speed with a value depending on a tumble ratio as exponent.

5 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 1 ,
wherein a virtual heat generation rate maximum time is set, wherein a virtual first-half combustion period between the ignition time obtained according to an actual spark time and the virtual heat generation rate maximum time is compared with an estimated first-half combustion period based on a physical quantity at the virtual heat generation rate maximum time so as to calculate a true first-half combustion period as the estimated first-half combustion period that coincides with the virtual first-half combustion period, and wherein the heat generation rate waveform is calculated using the true first-half combustion period.

6 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 1 ,
wherein the heat generation rate waveform is approximated by a triangular waveform with a crank angle period from the ignition of the air-fuel mixture to combustion completion as a base and the heat generation rate at the heat generation rate maximum time as an apex, and wherein, in the triangular waveform, the base of the triangle, which represents the heat generation rate from the ignition time to the heat generation rate maximum time, is defined as the first-half combustion period.

7 . (canceled)

8 . A method for calculating a heat generation rate waveform of a spark-ignition internal combustion engine, comprising the steps of:
defining, within a combustion period of an air-fuel mixture, a period from an ignition time to a heat generation rate maximum time where a heat generation rate is maximum as a first-half combustion period that is one of characteristic values of the heat generation rate waveform; estimating the first-half combustion period based on a physical quantity at the heat generation rate maximum time; calculating the heat generation rate waveform using the estimated first-half combustion period, and estimating the first-half combustion period as a value not affected by at least one of an engine load rate, an air-fuel ratio, an exhaust gas recirculation (EGR) rate and an oil-water temperature.

9 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 2 ,
wherein a virtual heat generation rate maximum time is set, wherein a virtual first-half combustion period between the ignition time obtained according to an actual spark time and the virtual heat generation rate maximum time is compared with an estimated first-half combustion period based on a physical quantity at the virtual heat generation rate maximum time so as to calculate a true first-half combustion period as the estimated first-half combustion period that coincides with the virtual first-half combustion period, and wherein the heat generation rate waveform is calculated using the true first-half combustion period.

10 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 3 ,
wherein a virtual heat generation rate maximum time is set, wherein a virtual first-half combustion period between the ignition time obtained according to an actual spark time and the virtual heat generation rate maximum time is compared with an estimated first-half combustion period based on a physical quantity at the virtual heat generation rate maximum time so as to calculate a true first-half combustion period as the estimated first-half combustion period that coincides with the virtual first-half combustion period, and wherein the heat generation rate waveform is calculated using the true first-half combustion period.

11 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 4 ,
wherein a virtual heat generation rate maximum time is set, wherein a virtual first-half combustion period between the ignition time obtained according to an actual spark time and the virtual heat generation rate maximum time is compared with an estimated first-half combustion period based on a physical quantity at the virtual heat generation rate maximum time so as to calculate a true first-half combustion period as the estimated first-half combustion period that coincides with the virtual first-half combustion period, and wherein the heat generation rate waveform is calculated using the true first-half combustion period.

12 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 2 ,
wherein the heat generation rate waveform is approximated by a triangular waveform with a crank angle period from the ignition of the air-fuel mixture to combustion completion as a base and the heat generation rate at the heat generation rate maximum time as an apex, and wherein, in the triangular waveform, the base of the triangle, which represents the heat generation rate from the ignition time to the heat generation rate maximum time, is defined as the first-half combustion period.

13 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 3 ,
wherein the heat generation rate waveform is approximated by a triangular waveform with a crank angle period from the ignition of the air-fuel mixture to combustion completion as a base and the heat generation rate at the heat generation rate maximum time as an apex, and wherein, in the triangular waveform, the base of the triangle, which represents the heat generation rate from the ignition time to the heat generation rate maximum time, is defined as the first-half combustion period.

14 . The heat generation rate waveform calculation device of an internal combustion engine according to claim 4 ,
wherein the heat generation rate waveform is approximated by a triangular waveform with a crank angle period from the ignition of the air-fuel mixture to combustio

Assignees

• Toyota Motor Co Ltd

Inventors

• IMAEDA Munenori

Classifications

• F02D35/028

  by determining the combustion timing or phasing · CPC title

• F02D35/02

  on interior conditions · CPC title

• F02D37/02

  one of the functions being ignition · CPC title

• F02B77/084 Primary

  indicating economy · CPC title

• F02D2200/101

  Engine speed · CPC title