Control apparatus for internal combustion engine

Patent metadata

Field	Value
Publication number	US-2016290273-A1
Application number	US-201615088619-A
Country	US
Kind code	A1
Filing date	Apr 1, 2016
Priority date	Apr 3, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

Embodiments of the present invention prevent the occurrence of rapid or intense self-ignition of fuel in an internal combustion engine that performs diesel combustion using a fuel having a relatively high self-ignition temperature. Pre-combustion is brought about by spark ignition during the compression stroke. Thereafter, main injection by an in-cylinder injection valve is performed before the top dead center of the compression stroke. In consequence, combustion of the fuel injected by the main injection is started by flame generated by the pre-combustion, and self-ignition and diffusion combustion of fuel occurs subsequently. Moreover, in at least a part of the operation range of the internal combustion engine, middle injection is performed at a time after the spark ignition of the pre-injected fuel and before the main injection. The fuel injected by the middle injection is burned by propagation of flame.

First claim

What is claimed is:

1 . A control apparatus for an internal combustion engine comprising:
a fuel injection valve that injects fuel radially from a location near a center of a combustion chamber of the internal combustion engine; an ignition plug whose position relative to said fuel injection valve is set in such a way that a part of fuel spray injected through said fuel injection valve passes through an ignition-capable region and the ignition plug can ignite the fuel spray directly; and a controller comprising at least one processor configured to perform pre-injection through said fuel injection valve at a pre-injection time during the compression stroke, ignite pre-spray, which is fuel spray formed by the pre-injection, by said ignition plug, and start to perform main injection through said fuel injection valve at a main injection time after the ignition of said pre-spray by said ignition plug and before a top dead center of the compression stroke that is set in such a way that combustion of the fuel injected by said main injection is started by flame generated by ignition of said pre-spray, thereby causing self-ignition of fuel to occur and causing at least a portion of the fuel injected by said main injection to be burned by diffusion combustion, wherein in at least a part of an operation range of the internal combustion engine, said controller is to perform middle injection in addition to said pre-injection and said main injection in one combustion cycle at a middle injection time after the ignition of said pre-spay by said ignition plug and before said main injection time to inject a quantity of fuel smaller than the quantity of fuel injected by said pre-injection in the same combustion cycle through said fuel injection valve, thereby causing the fuel injected by said middle injection to be burned by propagation of flame starting from flame generated by the ignition of said pre-spray.

2 . A control apparatus for an internal combustion engine according to claim 1 , wherein said part of the operation range is an operation range in which the engine load of the internal combustion engine is higher than a predetermined load, and said controller is to perform said pre-injection and said main injection in one combustion cycle in the operation range in which the engine load of the internal combustion engine is lower than or equal to said predetermined load and is to perform said middle injection in addition to said pre-injection and said main injection in one combustion cycle in the operation range in which the engine load of the internal combustion engine is higher than said predetermined load.

3 . A control apparatus for an internal combustion engine according to claim 1 , wherein the quantity of fuel injected by said middle injection is smaller than a smallest injected fuel quantity in said pre-injection in the entire operation range in which said pre-injection is performed.

4 . A control apparatus for an internal combustion engine according to claim 1 , wherein the quantity of fuel injected by said middle injection is smaller than a smallest fuel injection quantity with which self-ignition of fuel will occur in a period after said middle injection is performed and before said main injection time, said smallest fuel injection quantity being calculated using the Livengood-Wu integral equation based on the quantity of air in the cylinder, the pressure in the cylinder, and the temperature in the cylinder at said middle injection time.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ochi Yuta

Classifications

• F02B23/101

  the injector being placed on or close to the cylinder centre axis, e.g. with mixture formation using spray guided concepts · CPC title

• F02D41/30 Primary

  Controlling fuel injection {(F02D41/182, F02D41/24 take precedence)} · CPC title

• F02D41/403 Primary

  with pilot injections · CPC title

• F01N3/035

  with catalytic reactors · CPC title

• F02D41/402

  Multiple injections · CPC title