Control system for stopping and starting vehicle engine

• US 20040029677A1
• Filed: 08/05/2003
• Published: 02/12/2004
• Est. Priority Date: 08/07/2002
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Mori, Ryuichi, Okajima, Hiroyuki, Kitano, Kazuhiko, Fushimi, Koichi
• Granted Patent: US 6,913,558 B2
• Time in Patent Office: Days
• US Class Current: 477/3
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 2510/0241 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/1075 fluid pressure, e.g. oil pressure
• CPC Class Codes: F02D 2200/023 Temperature of lubricating oil or working fluid
• CPC Class Codes: F02D 2200/0602 Fuel pressure
• CPC Class Codes: F02D 2250/41 Control to generate negative pressure in the intake manifold, e.g. for fuel vapor purging or brake booster
• CPC Class Codes: F02N 11/084 State of vehicle accessories, e.g. air condition or power steering
• CPC Class Codes: F02N 2200/0802 Transmission state, e.g. gear ratio or neutral state
• CPC Class Codes: F16H 2312/14 Going to, or coming from standby operation, e.g. for engine start-stop operation at traffic lights
• CPC Class Codes: F16H 61/0025 Supply of control fluid; Pumps therefore
• CPC Class Codes: F16H 61/0031 using auxiliary pumps, e.g. pump driven by a different power source than the engine
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/917 with transmission for changing gear ratio
• CPC Class Codes: Y10S 903/919 : Stepped shift

Abstract

An engine stop and start control system for securing a normal line pressure in a hydraulic circuit of the transmission. The system has an engine as a power source for driving the vehicle; a transmission; a mechanical oil pump, operated by the power produced by the engine, for supplying oil pressure to the transmission; an automatic engine stopping and starting section for automatically stopping the engine under predetermined stopping conditions and automatically starting the engine under predetermined starting conditions; and an electric oil pump operated when the predetermined stopping conditions are satisfied, so as to supply the oil pressure to the transmission. The automatic engine stopping and starting section has a control section for prohibiting the automatic engine stop when the line pressure in a hydraulic circuit for supplying oil pressure to the transmission is equal to or lower than a predetermined value while the engine is operated.

Claims

1. An engine stop and start control system for a vehicle, wherein the vehicle comprises:

an engine as a power source for driving the vehicle;

a transmission for transmitting power produced by the engine to an output shaft of the vehicle; and

a mechanical oil pump, operated by the power produced by the engine, for supplying oil pressure to the transmission via an oil pressure supply section, and

the control system comprises;

an automatic engine stopping and starting section for automatically stopping the engine under predetermined stopping conditions and automatically starting the engine under predetermined starting conditions; and

an electric oil pump operated when the predetermined stopping conditions are satisfied, so as to supply the oil pressure to the transmission,

wherein the automatic engine stopping and starting section has a control section for prohibiting the automatic engine stop when a line pressure, which is the oil pressure in the oil pressure supply section, is equal to or lower than a predetermined value while the engine is operated.

2. An engine stop and start control system as claimed in claim 1, wherein the predetermined value is determined depending on the number of rotations of an output shaft of the engine.

3. An engine stop and start control system as claimed in claim 1, wherein the control section prohibits the automatic engine stop when the state in which the line pressure is equal to or lower than the predetermined value has continued for a predetermined time.

12. An engine stop and start control system as claimed in any one of claims 1, 4, 6, 8, 10, and 11, wherein:

the vehicle is a hybrid vehicle which further comprises an electric motor as a power source for driving the vehicle; and

the mechanical oil pump is operated by at least one of the power produced by the engine and power produced by the electric motor.

4. An engine stop and start control system for a vehicle, wherein the vehicle comprises:

an engine as a power source for driving the vehicle;

a transmission for transmitting power produced by the engine to an output shaft of the vehicle; and

a mechanical oil pump, operated by the power produced by the engine, for supplying oil pressure to the transmission, and

the control system comprises;

an automatic engine stopping and starting section for automatically stopping the engine under predetermined stopping conditions and automatically starting the engine under predetermined starting conditions; and

an electric oil pump operated when the predetermined stopping conditions are satisfied, so as to supply the oil pressure to the transmission via an oil pressure supply section,

wherein the automatic engine stopping and starting section has a control section for restarting the engine when a line pressure, which is the oil pressure in the oil pressure supply section, is equal to or lower than a predetermined value while the engine is automatically stopped.

5. An engine stop and start control system as claimed in claim 4, wherein the control section restarts the engine when the state in which the line pressure is equal to or lower than the predetermined value has continued for a predetermined time.

6. An engine stop and start control system for a vehicle, wherein the vehicle comprises:

an engine as a power source for driving the vehicle;

a transmission for transmitting power produced by the engine to an output shaft of the vehicle; and

a mechanical oil pump, operated by the power produced by the engine, for supplying oil pressure to the transmission, and

the control system comprises;

an automatic engine stopping and starting section for automatically stopping the engine under predetermined stopping conditions and automatically starting the engine under predetermined starting conditions; and

an electric oil pump operated when the predetermined stopping conditions are satisfied, so as to supply the oil pressure to the transmission,

wherein the automatic engine stopping and starting section has a control section for restarting the engine when a value of current flowing through a driving motor for driving the electric oil pump is out of a predetermined range while the engine is automatically stopped.

7. An engine stop and start control system as claimed in claim 6, wherein the control section restarts the engine when the state in which the value of current is out of the predetermined range has continued for a predetermined time.

8. An engine stop and start control system for a vehicle, wherein the vehicle comprises:

an engine as a power source for driving the vehicle;

a transmission for transmitting power produced by the engine to an output shaft of the vehicle; and

a mechanical oil pump, operated by the power produced by the engine, for supplying oil pressure to the transmission, and

the control system comprises;

an automatic engine stopping and starting section for automatically stopping the engine under predetermined stopping conditions and automatically starting the engine under predetermined starting conditions; and

an electric oil pump operated when the predetermined stopping conditions are satisfied, so as to supply the oil pressure to the transmission via an oil pressure supply section, where one of a driving voltage and a duty ratio in pulse width modulation of a driving motor for driving the electric oil pump is controlled in a manner such that one of a line pressure, which is the oil pressure in the oil pressure supply section, and a value of current flowing through the driving motor coincides with a predetermined command value,

wherein the automatic engine stopping and starting section has a control section for restarting the engine when one of the driving voltage and the duty ratio is equal to or greater than a predetermined value while the engine is automatically stopped.

9. An engine stop and start control system as claimed in claim 8, wherein the control section restarts the engine when the state in which one of the driving voltage and the duty ratio is equal to or greater than the predetermined value has continued for a predetermined time.

10. An engine stop and start control system for a vehicle, wherein the vehicle comprises:

an engine as a power source for driving the vehicle;

a transmission for transmitting power produced by the engine to an output shaft of the vehicle; and

a mechanical oil pump, operated by the power produced by the engine, for supplying oil pressure to the transmission, and

the control system comprises;

an automatic engine stopping and starting section for automatically stopping the engine under predetermined stopping conditions and automatically starting the engine under predetermined starting conditions; and

an electric oil pump operated when the predetermined stopping conditions are satisfied, so as to supply the oil pressure to the transmission,

wherein the automatic engine stopping and starting section has a control section for restarting the engine when a temperature of hydraulic oil supplied to the transmission is equal to or higher than a predetermined value while the engine is automatically stopped.

11. An engine stop and start control system for a vehicle, wherein the vehicle comprises:

an engine as a power source for driving the vehicle;

a transmission for transmitting power produced by the engine to an output shaft of the vehicle; and

a mechanical oil pump, operated by the power produced by the engine, for supplying oil pressure to the transmission, and

the control system comprises;

an automatic engine stopping and starting section for automatically stopping the engine under predetermined stopping conditions and automatically starting the engine under predetermined starting conditions; and

an electric oil pump operated when the predetermined stopping conditions are satisfied, so as to supply the oil pressure to the transmission,

wherein the automatic engine stopping and starting section has a control section for prohibiting the automatic engine stop when a slip ratio of a clutch for a gear for starting the vehicle in the transmission exceeds a predetermined range in a predetermined time after the engine is restarted from the state in which the engine is automatically stopped.