Start-up control device for engine

Patent metadata

Field	Value
Publication number	US-10465624-B2
Application number	US-201715791777-A
Country	US
Kind code	B2
Filing date	Oct 24, 2017
Priority date	Oct 25, 2016
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

When a crankshaft reversely rotates immediately before a stoppage of an engine, the amount of fuel injection in a cylinder in an expansion stroke is controlled to acquire a target air-fuel ratio in accordance with the amount of air in the cylinder. When the electronic control unit determines that the exhaust valve is opened at the time of reverse rotation, the amount of fuel injection is determined by considering a change in the amount of air due to exchange of gas with an exhaust path.

First claim

What is claimed is:

1. A start-up control device for an engine, the device comprising:
circuitry configured to:
start up a direct injection engine by executing fuel injection and ignition into a cylinder in an expansion stroke when a restart condition is established immediately before the engine stops; and
when a crankshaft reversely rotates before a rotation of the crankshaft stops:
determine whether or not an exhaust valve of the cylinder in the expansion stroke is opened at a time of the reverse rotation of the crankshaft,
determine an amount of fuel injection in accordance with a change in an amount of air in the cylinder in the expansion stroke due to exchange of gas with an exhaust path via the exhaust valve of the cylinder in the expansion stroke such that an air-fuel ratio of a mixture of fuel and the air reaches a target air-fuel ratio when it has been determined that the exhaust valve of the cylinder in the expansion stroke is opened at the time of the reverse rotation of the crankshaft,
cause a fuel injection valve to inject the fuel in accordance with the determined amount of fuel injection into the cylinder in the expansion stroke, and
ignite the fuel in the cylinder,

wherein reversely rotates includes rotation in a direction opposite to that in which the crankshaft rotates as a result of the start up, and
wherein the circuitry is configured to calculate the amount of air in the cylinder in the expansion stroke based on an opening timing of the exhaust valve of the cylinder in the expansion stroke when it has been determined that the exhaust valve of the cylinder in the expansion stroke is opened at the time of the reverse rotation of the crankshaft.

2. The start-up control device according to claim 1 , wherein the circuitry is configured to start up the engine without using a starter motor.

3. The start-up control device according to claim 1 , wherein the circuitry is configured to calculate the amount of air in the cylinder in the expansion stroke based on a closing timing of an intake valve in a compression stroke, the intake valve being included in the cylinder in the expansion stroke, when it has been determined that the exhaust valve of the cylinder in the expansion stroke is not opened at the time of the reverse rotation of the crankshaft.

4. The start-up control device according to claim 1 , wherein the circuitry is configured to calculate the amount of air in the cylinder in the expansion stroke based on at least one of a valve open period of the exhaust valve of the cylinder in the expansion stroke and an opening degree of the exhaust valve of the cylinder in the expansion stroke when it has been determined that the exhaust valve of the cylinder in the expansion stroke is opened at the time of the reverse rotation of the crankshaft.

5. The start-up control device according to claim 4 , wherein circuitry is configured to:
determine whether or not the valve open period of the exhaust valve of the cylinder in the expansion stroke is longer than a predetermined amount of time;
calculate the amount of air in the cylinder in the expansion stroke based on an opening timing of the exhaust valve of the cylinder in the expansion stroke when it has been determined that the exhaust valve of the cylinder in the expansion stroke is opened at the time of the reverse rotation of the crankshaft and that the valve open period of the exhaust valve of the cylinder in the expansion stroke is longer than the predetermined amount of time; and
calculate the amount of air in the cylinder in the expansion stroke based on at least one of the valve open period and the opening degree of the exhaust valve of the cylinder in the expansion stroke when it has been determined that the exhaust valve of the cylinder in the expansion stroke is opened at the time of the reverse rotation of the crankshaft and that the valve open period of the exhaust valve of the exhaust valve of the cylinder in the expansion stroke is shorter than or equal to the predetermined amount of time.

6. The start-up control device according to claim 1 , wherein the circuitry is configured to:
control fuel injection in the cylinder that is in the expansion stroke at the time of reverse rotation of the crankshaft when the crankshaft reversely rotates without a cylinder in a compression stroke passing a top dead center at a time when the restart condition is established, and
control fuel injection in the cylinder in the compression stroke passing the top dead center at the time when the restart condition is established when the cylinder in the compression stroke passes the top dead center and transitions to the expansion stroke.

7. The start-up control device according to claim 1 , wherein the circuitry is configured to control fuel injection in the cylinder that is in the expansion stroke at a time when the restart condition is established when the restart condition is established after the reverse rotation of the crankshaft.

8. The start-up control device according to claim 1 , wherein the circuitry is configured to
detect a stop position where the crankshaft temporarily stops rotating before the reverse rotation, and
determine that the exhaust valve is opened when the stop position is advanced with respect to a position of the crankshaft that corresponds to an opening timing of the exhaust valve in the cylinder in the expansion stroke.

9. A start-up control device for an engine, the device comprising:
circuitry configured to:
start up a direct injection engine by executing fuel injection and ignition into a cylinder in an expansion stroke when a restart condition is established immediately before the engine stops; and
when a crankshaft reversely rotates before a rotation of the crankshaft stops:
determine whether or not an exhaust valve of the cylinder in the expansion stroke is opened at a time of the reverse rotation of the crankshaft,
determine an amount of fuel injection in accordance with a change in an amount of air in the cylinder in the expansion stroke due to exchange of gas with an exhaust path via the exhaust valve of the cylinder in the expansion stroke such that an air-fuel ratio of a mixture of fuel and the air reaches a target air-fuel ratio when it has been determined that the exhaust valve of the cylinder in the expansion stroke is opened at the time of the reverse rotation of the crankshaft,
cause a fuel injection valve to inject the fuel in accordance with the determined amount of fuel injection into the cylinder in the expansion stroke, and
ignite the fuel in the cylinder,

wherein reversely rotates includes rotation in a direction opposite to that in which the crankshaft rotates as a result of the start up, and
wherein the circuitry is configured to calculate the amount of air in the cylinder in the expansion stroke based on at least one of a valve open period of the exhaust valve of the cylinder in the expansion stroke and an opening degree of the exhaust valve of the cylinder in the expansion stroke when it has been determined that the exhaust valve of the cylinder in the expansion stroke is opened at the time of the reverse rotation of the crankshaft.

10. The start-up control device according to claim 9 , wherein the circuitry is configured to start up the engine without using a starter motor.

11. The start-up control device according to claim 9 , wherein the circuitry is configured to calculate the amount of air in the cylinder in the expansion stroke based on a closing timing of an intake valve in a compression stroke, the intake valve being included in the cylinder in the expansion stroke, when it has been determined that the exhaust valve of the cylinder in the expansion stroke is not o

Assignees

• Toyota Motor Co Ltd
• Fujitsu Ten Ltd

Inventors

• Suzuki Yusuke
• Usui Kunihiko
• Koyama Kazuya

Classifications

• F02P5/045

  combined with electronic control of other engine functions, e.g. fuel injection (in general F02D37/02) · CPC title

• F02D41/40

  with means for controlling injection timing or duration · CPC title

• F02D41/065 Primary

  at hot start or restart (F02D41/067 takes precedence) · CPC title

• F02N99/006

  Providing a combustible mixture inside the cylinder · CPC title

• F02D41/009

  using means for generating position or synchronisation signals · CPC title