START-UP CONTROL DEVICE FOR ENGINE

• US 20180112610A1
• Filed: 10/24/2017
• Published: 04/26/2018
• Est. Priority Date: 10/25/2016
• Status: Active Grant

• Current Assignee: Fujitsu Ten Limited (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: SUZUKI, Yusuke, USUI, Kunihiko, KOYAMA, Kazuya
• Granted Patent: US 10,465,624 B2
• Time in Patent Office: Days
• CPC Class Codes: F02D 2041/389 for injecting directly into the cylinder
• CPC Class Codes: F02D 2200/0402 the parameter being determined by using a model of the engine intake or its components
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: F02D 41/065 at hot start or restart F02D41/067 takes precedence
• CPC Class Codes: F02D 41/1444 characterised by the characteristics of the combustion gases
• CPC Class Codes: F02D 41/1448 the characteristics being an exhaust gas pressure
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/40 with means for controlling injection timing or duration
• CPC Class Codes: F02N 2019/002 Aiding engine start by acting on fuel
• CPC Class Codes: F02N 99/006 Providing a combustible mixture inside the cylinder
• CPC Class Codes: F02P 5/045 combined with electronic control of other engine functions, e.g. fuel injection in general F02D37/02
• CPC Class Codes: Y02T 10/40 Engine management systems

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.

Claims

1. A start-up control device for an engine, the device comprising:

an electronic control unit 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 a stoppage of the engine, wherein;

when a crankshaft reversely rotates before a stoppage of rotation of the crankshaft, the electronic control unit is configured to cause a fuel injection valve to inject fuel into the cylinder in the expansion stroke, and is configured to control an amount of fuel injection in accordance with an amount of air in the cylinder in the expansion stroke such that an air-fuel ratio of a mixture of the fuel and the air reaches a target air-fuel ratio; and

the electronic control unit is configured to

determine whether or not an exhaust valve is opened at a time of reverse rotation of the crankshaft, and

determine the amount of fuel injection in accordance with a change in the amount of air in the cylinder due to exchange of gas with an exhaust path, when the electronic control unit determines that the exhaust valve is opened.

2. The start-up control device according to claim 1, wherein when the restart condition is established immediately before a stoppage of the engine, the electronic control unit is configured to start up the engine without using a starter motor by executing fuel injection and ignition into the cylinder in the expansion stroke.

3. The start-up control device according to claim 1, wherein when the electronic control unit determines that the exhaust valve is not opened, the electronic control unit is configured to calculate the amount of air in the cylinder 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.

4. The start-up control device according to claim 1, wherein when the exhaust valve is determined to be opened, the electronic control unit is configured to calculate the amount of air in the cylinder based on an opening timing of the exhaust valve of the cylinder in the expansion stroke.

5. The start-up control device according to claim 1, wherein when the exhaust valve is determined to be opened, the electronic control unit 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 and an opening degree of the exhaust valve of the cylinder in the expansion stroke.

6. The start-up control device according to claim 5, wherein:

the electronic control unit is configured to determine whether or not the valve open period of the exhaust valve is longer than a predetermined amount of time;

the electronic control unit is configured to calculate the amount of air in the cylinder based on an opening timing of the exhaust valve of the cylinder in the expansion stroke when the electronic control unit determines that the exhaust valve is opened and that the valve open period of the exhaust valve is longer than the predetermined amount of time; and

the electronic control unit is configured to 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 the electronic control unit determines that the exhaust valve is opened and that the valve open period of the exhaust valve is shorter than or equal to the predetermined amount of time.

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

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

9. The start-up control device according to claim 1, wherein the electronic control unit detects a stop position where the crankshaft temporarily stops rotating before reverse rotation, and determines 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.