Valve lift control systems and methods for engine startability

Patent metadata

Field	Value
Publication number	US-9488078-B2
Application number	US-201414487599-A
Country	US
Kind code	B2
Filing date	Sep 16, 2014
Priority date	Jun 27, 2014
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

A startup/shutdown control module selectively generates an engine startup command when an engine of the vehicle is off. A starter control module applies power to a starter motor when the engine startup command is generated. A valve control module, in response to the generation of the engine startup command: operates intake valves of cylinders of the engine in a low lift mode when an engine temperature is less than a predetermined temperature; and operates the intake valves of the cylinders of the engine in a high lift mode when the engine temperature is greater than the predetermined temperature.

First claim

What is claimed is:

1. An engine control system for a vehicle, comprising:
a startup/shutdown control module that selectively generates an engine startup command signal when an engine of the vehicle is off and that selectively shuts down the engine of the vehicle;
a starter control module that applies power to a starter motor when the engine startup command signal is generated; and
a valve control module that:
in response to the generation of the engine startup command signal:
operates intake valves of cylinders of the engine in a low lift mode when an engine temperature is less than a predetermined temperature; and
operates the intake valves of the cylinders of the engine in a high lift mode when the engine temperature is greater than the predetermined temperature;

when the startup/shutdown control module shuts down the engine in response to user input to an ignition system, operates the intake valves of the cylinders of the engine in the low lift mode; and
when the startup/shutdown control module shuts down the engine in response to a driver applying pressure to a brake pedal of the vehicle, operates the intake valves of the cylinders of the engine in the high lift mode.

2. The engine control system of claim 1 wherein:
the low lift mode corresponds to a first effective compression ratio; and
the high lift mode corresponds to a second effective compression ratio that is less than the first effective compression ratio.

3. The engine control system of claim 2 wherein, in response to the generation of the engine startup command signal, the valve control module:
engages a first set of intake cam lobes with the intake valves when the engine temperature is less than the predetermined temperature,
wherein the first set of intake cam lobes correspond to the first effective compression ratio; and
engages a second set of intake cam lobes with the intake valves when the engine temperature is greater than the predetermined temperature,
wherein the second set of intake cam lobes correspond to the second effective compression ratio.

4. The engine control system of claim 1 wherein the startup/shutdown control module generates the engine startup command signal in response to user input to the ignition system.

5. The engine control system of claim 1 wherein the startup/shutdown control module generates the engine startup command signal when the driver removes pressure from the brake pedal.

6. The engine control system of claim 1 wherein, in response to the generation of the engine startup command signal, the valve control module transitions operation of the intake valves from the high lift mode to the low lift mode when the engine temperature is less than the predetermined temperature.

7. The engine control system of claim 1 wherein, in response to the generation of the engine startup command signal, the valve control module transitions operation of the intake valves from the low lift mode to the high lift mode when the engine temperature is greater than the predetermined temperature.

8. The engine control system of claim 1 wherein the valve control module determines the engine temperature based on an engine coolant temperature measured using an engine coolant temperature sensor.

9. The engine control system of claim 1 wherein the valve control module determines the engine temperature based on a period since a last shutdown of the engine.

10. The engine control system of claim 1 wherein:
during operation in the low lift mode, the intake valves are opened at a first time, closed at a second time, and actuated a first distance; and
during operation in the high lift mode, the intake valves are opened at a third time that is before the first time, closed at a fourth time that is after the second time, and actuated a second distance that is greater than the first distance.

11. An engine control method for a vehicle, the engine control method comprising:
selectively generating an engine startup command signal when an engine of the vehicle is off;
applying power to a starter motor when the engine startup command signal is generated;
in response to the generation of the engine startup command signal:
operating intake valves of cylinders of the engine in a low lift mode when an engine temperature is less than a predetermined temperature; and
operating the intake valves of the cylinders of the engine in a high lift mode when the engine temperature is greater than the predetermined temperature;

in response to a first shut down of the engine of the vehicle performed in response to user input to an ignition system, operating the intake valves of the cylinders of the engine in the low lift mode; and
in response to a second shut down of the engine of the vehicle performed in response to a driver applying pressure to a brake pedal of the vehicle, operating the intake valves of the cylinders of the engine in the high lift mode.

12. The engine control method of claim 11 wherein:
the low lift mode corresponds to a first effective compression ratio; and
the high lift mode corresponds to a second effective compression ratio that is less than the first effective compression ratio.

13. The engine control method of claim 12 further comprising, in response to the generation of the engine startup command signal:
engaging a first set of intake cam lobes with the intake valves when the engine temperature is less than the predetermined temperature,
wherein the first set of intake cam lobes correspond to the first effective compression ratio; and
engaging a second set of intake cam lobes with the intake valves when the engine temperature is greater than the predetermined temperature,
wherein the second set of intake cam lobes correspond to the second effective compression ratio.

14. The engine control method of claim 11 further comprising generating the engine startup command signal in response to second user input to the ignition system.

15. The engine control method of claim 11 further comprising,
after the second shut down of the engine, generating the engine startup command signal when the driver removes pressure from the brake pedal.

16. The engine control method of claim 11 further comprising, in response to the generation of the engine startup command signal, transitioning operation of the intake valves from the high lift mode to the low lift mode when the engine temperature is less than the predetermined temperature.

17. The engine control method of claim 11 further comprising, in response to the generation of the engine startup command signal, transitioning operation of the intake valves from the low lift mode to the high lift mode when the engine temperature is greater than the predetermined temperature.

18. The engine control method of claim 11 further comprising determining the engine temperature based on an engine coolant temperature measured using an engine coolant temperature sensor.

19. The engine control method of claim 11 further comprising determining the engine temperature based on a period since a last shut down of the engine.

20. The engine control method of claim 11 wherein:
during operation in the low lift mode, the intake valves are opened at a first time, closed at a second time, and actuated a first distance; and
during operation in the high lift mode, the intake valves are opened at a third time that is before the first time, closed at a fourth time that is after the second time, and actuated a second distance that is greater than the first distance.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Douglas Scot A

Classifications

• F02D41/064

  at cold start (F02D41/067 takes precedence) · CPC title

• F02N2200/023

  Engine temperature · CPC title

• F01L1/04

  by means of cams, camshafts, cam discs, eccentrics or the like (F01L1/10 takes precedence) · CPC title

• F01L1/344

  changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear · CPC title

• F02D2041/001

  for engines with variable valve actuation · CPC title