Control device for internal combustion engine

Patent metadata

Field	Value
Publication number	US-2016123264-A1
Application number	US-201314896292-A
Country	US
Kind code	A1
Filing date	Jun 5, 2013
Priority date	Jun 5, 2013
Publication date	May 5, 2016
Grant date	—

Abstract

A control device for an internal combustion engine according to the present invention (the present device) changes the combustion state of air fuel mixture such that if at least the load on the engine 10 falls within the range between a first threshold value Pem 1 and a second threshold value Pem 2, a heat release rate gravity center position Gc is equal to a given crank angle θa independent of an engine load, or if the engine load falls within the range beyond the second threshold value Pem 2, the heat release rate gravity center position Gc is changed to a value on a retarded angle side in a range closer to the retarded angle side than the given crank angle θa as the engine load is increased. A combustion state is changed by, for example, one or more of combustion parameters such as a main injection period of fuel, a fuel injection pressure (common-rail injection system pressure), the injection quantity, the timing, and the number of times of pilot injection, a turbocharging pressure, and an EGR amount.

First claim

1 . A control device for an internal combustion engine,
the control device comprising: an electronic control unit configured to set a parameter for controlling a combustion state of fuel that is supplied to a cylinder of the internal combustion engine such that, if a load on the internal combustion engine at least falls within a range between a first threshold value and a second threshold value that is greater than the first threshold value, a heat release rate gravity center position of the internal combustion engine is a predetermined crank angle independent of the load on the internal combustion engine, and configured to set the parameter for controlling a combustion state of the internal combustion engine such that, if the load on the internal combustion engine falls within a range beyond the second threshold value, the heat release rate gravity center position is a crank angle closer to a retarded angle side as the load is increased, within a range on the retarded angle side from the predetermined crank angle.

2 . The control device according to claim 1 , wherein
the electronic control unit is configured to set the second threshold value at a smaller value at a higher rotational speed of the internal combustion engine.

3 . The control device according to claim 1 , wherein
the electronic control unit is configured to set the parameter for controlling the combustion state of the internal combustion engine such that, if the load on the internal combustion engine falls within the range beyond the second threshold value, the heat release rate gravity center position is a crank angle closer to the retarded angle side at a higher rotational speed of the internal combustion engine.

4 . The control device according to claim 1 , wherein
the electronic control unit is configured to set the second threshold value as a value of the load corresponding to an operating state in which, in a case where a fuel injection quantity is increased in response to an increase in load on the internal combustion engine, a maximum value of a pressure in the cylinder becomes higher than an allowable pressure if the heat release rate gravity center position is not caused to be changed to a crank angle closer to the retarded angle side than the predetermined crank angle.

5 . The control device according to claim 1 , wherein
the electronic control unit is configured to calculate the heat release rate gravity center position as a crank angle that is determined in accordance with the load on the internal combustion engine or a fuel injection quantity, and an engine rotational speed.

6 . The control device according to claim 1 , wherein
the electronic control unit is configured to set the predetermined crank angle as a crank angle at which a sum of a cooling loss of the engine and an exhaust loss of the engine is minimized, or a crank angle within a predetermined range from the crank angle.

7 . The control device according to claim 1 , wherein
the electronic control unit is configured to calculate the heat release rate gravity center position is as a crank angle corresponding to a geometric gravity center of a region that is surrounded by a waveform that depicts a heat release rate in a graph in which a crank angle is set to one axis and the heat release rate is set to another axis orthogonal to the one axis, and by the one axis.

8 . The control device according to claim 1 , wherein
the electronic control unit is configured to calculate the heat release rate gravity center position as a specific crank angle at which a value obtained by integrating, with respect to crank angle, a product of a crank angle difference between any crank angle on an advanced angle side from a specific crank angle and the specific crank angle, and a heat release rate at the any crank angle is equal to a value obtained by integrating, with respect to crank angle, a product of a crank angle difference between any crank angle on the retarded angle side from the specific crank angle and the specific crank angle, and the heat release rate at the any crank angle.

9 . The control device according to claim 1 , wherein
the electronic control unit is configured to calculate the heat release rate gravity center position as a specific crank angle at which a value obtained by integrating, in one combustion stroke, with respect to the crank angle, a value that corresponds to a product of a value obtained by subtracting the specific crank angle from any crank angle and a heat release rate at the any crank angle, is zero.

10 . The control device according to claim 1 , wherein
the electronic control unit is configured to calculate the heat release rate gravity center position as a crank angle that is calculated based on an following expression,

Gc
=

∫
CAs
CAe



(

θ
-
CAs

)







Q


(
θ
)




θ

∫
CAs
CAe







Q


(
θ
)




θ

+
CAs

(
1
)

where Gc denotes a crank angle of the heat release rate gravity center position, CAs denotes a combustion starting crank angle in one

Assignees

• Toyota Motor Co Ltd

Inventors

• Oyagi Hiroshi
• Iwata Kazuyasa
• Yamashita Akira

Classifications

• F02D41/403

  with pilot injections · CPC title

• F02D41/40

  with means for controlling injection timing or duration · CPC title

• F02D41/263 Primary

  the program execution being modifiable by physical parameters · CPC title

• F02D41/1446

  the characteristics being exhaust temperatures · CPC title

• F02D35/026

  using an estimation · CPC title