Control apparatus and control method for internal combustion engine

• US 20070084425A1
• Filed: 10/03/2006
• Published: 04/19/2007
• Est. Priority Date: 10/18/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ikeda, Kazuto, Morita, Hiroshi, Hirose, Kiyoo
• Granted Patent: US 7,331,316 B2
• Time in Patent Office: Days
• US Class Current: 123/90.100
• CPC Class Codes: F01L 1/344 changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
• CPC Class Codes: F01L 13/0015 for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
• CPC Class Codes: F01L 2001/0537 Double overhead camshafts [DOHC]
• CPC Class Codes: F01L 2001/34483 Phaser return springs
• CPC Class Codes: F01L 2800/00 Methods of operation using a variable valve timing mechanism
• CPC Class Codes: F01L 2800/01 Starting
• CPC Class Codes: F02D 13/0226 changing valve lift or valve lift and timing
• CPC Class Codes: F02D 13/0261 Controlling the valve overlap
• CPC Class Codes: F02D 2013/0292 in the start-up phase, e.g. for warming-up cold engine or catalyst
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0255 to accelerate the warming-up of the exhaust gas treating apparatus at engine start
• CPC Class Codes: F02D 41/068 for warming-up
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

If it is determined that an engine has been started, an engine coolant temperature is detected. If the engine coolant temperature is equal to or lower than a threshold value, the catalyst quick warm-up control is started to retard ignition timing, and a signal indicating a command to increase an operate angle is transmitted to a VVLA controller. When a VVT hydraulic pressure is increased to a predetermined value, a signal indicating a command to decrease the operate angle is transmitted to the VVLA controller, and a signal indicating a command to advance open timing of an intake valve is transmitted to a VVT controller so that the open timing of the intake valve is not changed. If the engine coolant temperature is equal to or higher than a threshold value, the catalyst quick warm-up control ends, and the ignition timing is returned to normal timing.

Claims

1. A control apparatus for an internal combustion engine;

comprising;

an electric variable valve mechanism that is actuated by an electric actuator;

a warm-up determination portion that determines, after the internal combustion engine is started, whether a warm-up needs to be performed;

a first control portion that controls, if it is determined that the warm-up needs to be performed, the electric variable valve mechanism so that a valve overlap duration is increased; and

a second control portion that controls the internal combustion engine so that ignition timing is retarded based on an increase in the valve overlap duration.

2. The control apparatus according to claim 1, further comprising:

a hydraulic variable valve mechanism that is hydraulically actuated by hydraulic fluid discharged from an oil pump that is driven by the internal combustion engine;

an operation determination portion that determines, based on a pressure of the hydraulic fluid, whether the hydraulic variable valve mechanism is able to operate properly; and

a switching portion that switches, if it is determined that the hydraulic variable valve mechanism is able to operate properly, a mechanism used to increase the valve overlap duration from the electric variable valve mechanism to the hydraulic variable valve mechanism.

3. The control apparatus according to claim 2, wherein

the operation determination portion determines, if the pressure of the hydraulic fluid is equal to or higher than a predetermined pressure, that the hydraulic variable valve mechanism is able to operate properly.

4. The control apparatus according to claim 2, wherein

the switching portion switches the mechanism used to increase the valve overlap duration from the electric variable valve mechanism to the hydraulic variable valve mechanism so that open timing of an intake valve of the internal combustion engine is not changed.

5. The control apparatus according to claim 1, wherein

the warm-up determination portion determines whether a warm-up for activating a catalyst, which is included in an exhaust gas purification mechanism arranged in an exhaust system of the internal combustion engine and which purifies exhaust gas, needs to be performed.

6. The control apparatus according to claim 1, wherein

the electric variable valve mechanism changes an operate angle of at least one of an intake valve and an exhaust valve of the internal combustion engine.

7. The control apparatus according to claim 1, wherein

the electric variable valve mechanism changes an operate angle and a valve lift of at least one of an intake valve and an exhaust valve of the internal combustion engine.

8. The control apparatus according to claim 1, wherein

the hydraulic variable valve mechanism changes actuation timing of at least one of an intake valve and an exhaust valve of the internal combustion engine.

9. A control method for an internal combustion engine, comprising

determining, after the internal combustion engine is started, whether a warm-up needs to be performed;

controlling, if it is determined that the warm-up needs to be performed, an electric variable valve mechanism, which is actuated by an electric actuator, so that a valve overlap duration is increased; and

controlling the internal combustion engine so that ignition timing is retarded based on an increase in the valve overlap duration.

10. The control method according to claim 9, further comprising:

determining, based on a pressure of hydraulic fluid discharged from an oil pump that is driven by the internal combustion engine, whether a hydraulic variable valve mechanism, which is hydraulically actuated by the hydraulic fluid, is able to operate properly; and

switching, if it is determined that the hydraulic variable valve mechanism is able to operate properly, a mechanism used to increase the valve overlap duration from the electric variable valve mechanism to the hydraulic variable valve mechanism.

11. The control method according to claim 10, wherein

it is determined, if the pressure of the hydraulic fluid is equal to or higher than a predetermined pressure, that the hydraulic variable valve mechanism is able to operate properly.

12. The control method according to claim 10, wherein

the mechanism used to increase the valve overlap duration is switched from the electric variable valve mechanism to the hydraulic variable valve mechanism so that open timing of an intake valve of the internal combustion engine is not changed.

13. The control method according to claim 9, wherein

it is determined whether a warm-up for activating a catalyst, which is included in an exhaust gas purification mechanism arranged in an exhaust system of the internal combustion engine and which purifies exhaust gas, needs to be performed.

14. The control method according to claim 9, wherein

an operate angle of at least one of an intake valve and an exhaust valve of the internal combustion engine is changed by the electric variable valve mechanism.

15. The control method according to claim 9, wherein

an operate angle and a valve lift of at least one of an intake valve and an exhaust valve of the internal combustion engine is changed by the electric variable valve mechanism.

16. The control method according to claim 9, wherein

actuation timing of at least one of an intake valve and an exhaust valve of the internal combustion engine is changed by the hydraulic variable valve mechanism.