Control system for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10280859-B2
Application number	US-201615138375-A
Country	US
Kind code	B2
Filing date	Apr 26, 2016
Priority date	Apr 28, 2015
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

A control system reduces the amount of fuel injected from a second fuel injector in one cycle to an amount smaller than a second basic injection amount according to operating conditions of an internal combustion engine, and increases the amount of fuel injected from a first fuel injector in one cycle to an amount larger than a first basic injection amount according to operating conditions of the engine, during a predetermined period after a flow restricting operation is finished, so as to reduce fluctuations in the air-fuel ratio due to fluctuations in the wall temperature.

First claim

What is claimed is:

1. A control system for an internal combustion engine, the control system comprising:
a first fuel injector that injects fuel into a cylinder of the internal combustion engine;
a second fuel injector that injects fuel into an intake passage of the internal combustion engine; and
an electronic control unit (ECU) including a processor and a memory, wherein
the electronic control unit is configured to:
(a) control a water pump and perform a flow restricting operation, wherein when the internal combustion engine is in a cold state, flow rate of a coolant circulating in the internal combustion engine is restricted to a predetermined flow rate or less, or circulation of the coolant in the internal combustion engine is stopped,
(b) during the flow restricting operation, perform normal injection control to control the first fuel injector and the second fuel injector, such that an amount of the fuel injected from the first fuel injector per cycle is equal to a first basic injection amount corresponding to an operating conditions of the internal combustion engine, and an amount of the fuel injected from the second fuel injector per cycle is equal to a second basic injection amount corresponding to the operating conditions of the internal combustion engine,
(c) perform injection control to reduce fluctuation of air-fuel ratio under fluctuating water temperature to control the first fuel injector and the second fuel injector, such that the amount of the fuel injected from the first fuel injector per cycle is larger than the first basic injection amount corresponding to the operating condition of the internal combustion engine, and the amount of the fuel injected from the second fuel injector per cycle is smaller than the second basic injection amount, during a predetermined period (from time t 1 to time t 2 ) after the flow restricting operation ends, and
(d) after the predetermined period, perform the normal injection control to control the first fuel injector and the second fuel injector, such that the amount of the fuel injected from the first fuel injector per cycle is equal to the first basic injection amount and the amount of the fuel injected from the second fuel injector per cycle is equal to the second basic injection amount.

2. The control system according to claim 1 , wherein the electronic control unit is configured to control the first fuel injector and the second fuel injector, such that the amount of the fuel injected from the second fuel injector in one cycle is equal to or smaller than a predetermined fuel amount, during the predetermined period after the fuel restricting operation is finished.

3. The control system according to claim 1 , wherein the predetermined period is a period from a time when the flow restricting operation ends to a time when a temperature of the entire volume of the coolant is homogenized.

4. The control system according to claim 1 , wherein the predetermined period is a period from a time when the flow restricting operation is finished to a time when an amount of work of the water pump reaches a predetermined amount of work.

5. A control system for an internal combustion engine, the control system comprising:
a first fuel injector that injects fuel into a cylinder of the internal combustion engine;
a second fuel injector that injects fuel into an intake passage of the internal combustion engine; and
an electronic control unit (ECU) including a processor and a memory, wherein
the electronic control unit is configured to:
(a) control a water pump and perform a flow restricting operation, wherein when the internal combustion engine is in a cold state, flow rate of a coolant circulating in the internal combustion engine is restricted to a predetermined flow rate or less, or circulation of the coolant in the internal combustion engine is stopped,
(b) during the flow restricting operation, perform normal injection control to control the first fuel injector and the second fuel injector, such that an amount of the fuel injected from the first fuel injector per cycle is equal to a first basic injection amount corresponding to an operating condition of the internal combustion engine, and an amount of the fuel injected from the second fuel injector per cycle is equal to a second basic injection amount corresponding to the operating condition of the internal combustion engine,
(c) perform injection control to reduce fluctuation of air-fuel ratio under fluctuating water temperature to control the first fuel injector and the second fuel injector, such that the amount of the fuel injected from the first fuel injector per cycle is larger than the first basic injection amount corresponding to the operating condition of the internal combustion engine, and the amount of the fuel injected from the second fuel injector per cycle is smaller than the second basic injection amount corresponding to the operating condition of the internal combustion engine, during a predetermined period from a first time when the flow restricting operation is finished to a second time when high-temperature coolant and low-temperature coolant are mixed homogeneously, and
(d) after the predetermined period, perform the normal injection control to control the first fuel injector and the second fuel injector, such that the amount of the fuel injected from the first fuel injector per cycle is equal to the first basic injection amount and the amount of the fuel injected from the second fuel injector per cycle is equal to the second basic injection amount.

6. The control system according to claim 5 , wherein the electronic control unit is configured to control the first fuel injector and the second fuel injector, such that the amount of the fuel injected from the second fuel injector in one cycle is equal to or smaller than a predetermined fuel amount, during the predetermined period after the fuel restricting operation is finished.

7. The control system according to claim 5 , wherein an amount of work of the water pump reaches a predetermined amount of work during the predetermined period.

Assignees

• Toyota Motor Co Ltd

Inventors

• Tsukagoshi Takahiro

Classifications

• F02D2200/021

  Engine temperature · CPC title

• F01P2003/027

  Cooling cylinders and cylinder heads in parallel · CPC title

• F01P2007/143

  using restrictions · CPC title

• F02D41/3094

  the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder · CPC title

• F01P7/16

  by thermostatic control · CPC title