Control device for compression self-ignition engine

Patent metadata

Field	Value
Publication number	US-2019107040-A1
Application number	US-201716086295-A
Country	US
Kind code	A1
Filing date	Nov 20, 2017
Priority date	Nov 22, 2016
Publication date	Apr 11, 2019
Grant date	—

Abstract

A compression self-ignition engine performs a SI combustion in which an air-fuel mixture is combusted due to flame propagation triggered by spark ignition, and a CI combustion in which the air-fuel mixture is combusted due to self-ignition induced by the flame propagation. An ECU comprises a first control means for controlling a SI ratio serving as an index relating to a ratio of a heat amount generated in the SI combustion with respect to a total heat amount generated in the SI and CI combustions or a heat amount generated in the CI combustion; and a second control means for controlling an in-cylinder temperature before the SI combustion. The ECU is configured to change a combustion state of each of the SI and CI combustions by both the first and second control means according to the operating state of the engine.

First claim

1 . A control device for a compression self-ignition engine, comprising:
an engine having a combustion chamber operable to combust an air-fuel mixture, an injector operable to inject fuel to supply the fuel into the combustion chamber, and a spark plug operable to ignite the air-fuel mixture in the combustion chamber, the engine configured to cause the air-fuel mixture in the combustion chamber to be self-ignited in association with the spark ignition of the spark plug; and a controller configured to control at least the injector and the spark plug to control an operation of the engine, wherein the engine performs a first combustion in which the air-fuel mixture is combusted due to a flame propagation triggered by a spark ignition of the spark plug, and a second combustion in which the air-fuel mixture is combusted due to a self-ignition induced by the flame propagation, wherein the controller comprises a processor configured to:
control a SI ratio serving as an index relating to a ratio of a heat amount generated in the first combustion with respect to a total heat amount generated in the first and second combustions or a heat amount generated in the second combustion, based on an operating state of the engine and during each combustion cycle of the engine; and
control an initial in-cylinder temperature which is an internal temperature of the combustion chamber before a start of the first combustion, based on the operating state of the engine and during each combustion cycle of the engine, and
wherein the controller is configured to change combustion states of both the first and second combustions by controlling both the SI ratio and the initial in-cylinder temperature according to the operating state of the engine, during each combustion cycle of the engine.

2 . The control device according to claim 1 , wherein the controller is configured to perform control of gradually lowering the initial in-cylinder temperature as an engine load serving as the operating state of the engine becomes higher.

3 . The control device according to claim 1 , wherein the controller is configured to control the SI ratio and the initial in-cylinder temperature such that a combustion gravity center position in a combustion corresponding to a combination of the first and second combustions is maintained approximately constant, irrespective of an engine load serving as the operating state of the engine.

4 . The control device according to claim 1 , further comprising a state quantity setting device configured to adjust an introduction of fresh air and burned gas into the combustion chamber of the engine so as to set an inside of the combustion chamber to a desired state,
wherein the controller is configured to control the state quantity setting device such that a ratio between fresh air and burned gas to be introduced into the combustion chamber is adjusted so as to adjust the initial in-cylinder temperature.

5 . The control device according to claim 1 , wherein the controller is configured to set a target SI ratio and a target initial in-cylinder temperature before the start of the first combustion each according to the operating state of the engine, and to perform control of adjusting the SI ratio and control of adjusting the initial in- cylinder temperature, so as to attain the target SI ratio and the target initial in-cylinder temperature.

6 . The control device according to claim 5 , further comprising a state quantity setting device configured to adjust an introduction of fresh air and burned gas into the combustion chamber of the engine so as to thereby set an inside of the combustion chamber to a desired state,
wherein the controller is configured to control the state quantity setting device such that a ratio between fresh air and burned gas to be introduced into the combustion chamber is adjusted so as to attain the target initial in-cylinder temperature, and to acquire an actual initial in-cylinder temperature before the start of the first combustion so as to control a spark ignition timing of the spark plug based on the acquired initial in-cylinder temperature, to thereby attain a self-ignition timing according to the target SI ratio and the target initial in-cylinder temperature.

7 . The control device according to claim 1 , wherein the controller is configured to adjust, as the initial in-cylinder temperature before the start of the first combustion, an in-cylinder temperature at a timing when a piston of the engine is located at a bottom dead center position in an intake stroke.

8 . A control device for a compression self-ignition engine, comprising:
an engine having a combustion chamber operable to combust an air-fuel mixture, an injector operable to inject fuel to supply the fuel into the combustion chamber, and a spark plug operable to ignite the air-fuel mixture in the combustion chamber, the engine configured to cause the air-fuel mixture in the combustion chamber to be self-ignited in association with the spark ignition of the spark plug; and a controller configured to control at least the injector and the spark plug to control an operation of the engine, wherein the engine performs a first combustion in which the air-fuel mixture is combusted due to a flame propagation triggered by a spark ignition of the spark plug, and a second combustion in which the air-fuel mixture is combusted due to a self-ignition induced by the flame propagation, wherein the controller comprises a processor configured to:
control a SI ratio serving as an index relating to a ratio of a heat amount generated in the first combustion with respect to a total heat amount generated in the first and second combustions or a heat amount generated in the second combustion, based on an operating state of the engine and during each combustion cycle of the engine; and
control a self-ignition timing which is a timing at which the self-ignition occurs, based on the operating state of the engine and during each combustion cycle of the engine, wherein the controller is configured to change combustion states of both the first and second combustions by controlling both the SI ratio and the initial in-cylinder temperature according to the operating state of the engine, during each combustion cycle of the engine.

9 . The control device according to claim 8 , wherein the controller is configured to perform control of gradually shifting the self-ignition timing toward a retard side, as an engine load serving as the operating state of the engine becomes higher.

10 . The control device according to claim 9 , wherein the controller is configured to shift the self-ignition timing toward the retard side to the extent that the self-ignition timing does not exceed a given retard limit.

11 . The control device according to claim 8 , wherein the controller is configured to control the SI ratio and the self-ignition timing such that a combustion gravity center position in a combustion corresponding to a combination of the first and second combustions is maintained approximately constant, irrespective of an engine load serving as the operating state of the engine.

12 . The control device according to claim 8 , wherein the controller is configured to control a spark ignition timing of the spark plug to adjust the self-ignition timing.

13 . The control device according to claim 8 , wherein the controller is configured to set a target SI ratio and a target self-ignition timing each according to the operating state of the engine, and to perform control of adjusting the SI ratio and the self-ignition timing, so as to attain the target SI ratio and the target self-ignition timing.

14 . Th

Assignees

• Mazda Motor

Inventors

• Tsumura Yuichiro

Classifications

• F02B23/10

  with separate admission of air and fuel into cylinder · CPC title

• F02D41/402

  Multiple injections · CPC title

• F02D2200/10

  Parameters related to the engine output, e.g. engine torque or engine speed · CPC title

• F02D37/02

  one of the functions being ignition · CPC title

• F02D41/401

  Controlling injection timing (F02D41/402 takes precedence) · CPC title