Engine starting apparatus for vehicles

• US 5,495,127 A
• Filed: 09/01/1994
• Issued: 02/27/1996
• Est. Priority Date: 09/02/1993
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Murakawa, Takaji, Tashiro, Hiroshi, Aota, Hiroyuki, Yagi, Toyoji
• Primary Examiner(s): LaBalle, Clayton E.
• Assistant Examiner(s): Cuneo, Christopher
• Application Number:
  US08/299,364
• Time in Patent Office: 544 Days
• Field of Search: 290/10, 290/22, 290/31, 290/38 R, 290/46, 123/179.1, 123/179.3, 123/179.28
• US Class Current: 290/31
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60L 2240/486 Operating parameters
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 2510/0208 Clutch engagement state, e.g. engaged or disengaged
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 11/0859 specially adapted to the type of the starter motor or integrated into it
• CPC Class Codes: F02N 2011/0896 Inverters for electric machines, e.g. starter-generators
• CPC Class Codes: F02N 2200/022 Engine speed
• CPC Class Codes: F02N 2300/104 Control of the starter motor torque
• CPC Class Codes: F02N 2300/106 Control of starter current
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

Disclosed is an engine starting apparatus which suppresses engine vibrations and noises during engine cranking and reduces consumption of electric power supplied for engine cranking. When an engine starts to rotate to produce its torque, electric power supplied to a starter motor for engine cranking is reduced gradually so that a sum of torques produced by the starter motor and the engine may be prevented from increasing excessively. In the case a generator/motor is used for engine starting, operation of the generator/motor is switched from motor operation to generator operation for suppressing excessive speed rise when engine starting is completed.

Claims

1. A starting apparatus for an engine comprising:

a generator/motor capable of starting an engine by motor operation when energized by energization current and generating electric power by generator operation when driven by said engine;

a crank angle sensor for detecting crank angle of said engine;

a power control unit for switching operational mode of said generator/motor between said motor operation and said generator operation and for controlling torque generated by said motor operation of said generator/motor; and

controller for controlling said power control unit in response to said crank angle detected by said crank angle sensor,

wherein said controller includes;

first means for instructing to said control unit so that said motor operation of said generator/motor is performed when a rotational speed of said engine is below a first predetermined value;

second means for instructing to said control unit so that torque generated by said motor operation is gradually reduced when said rotational speed of said engine reaches a second predetermined value lower than said first predetermined value; and

third means for instructing said control unit so that said motor operation of said generator/motor is terminated when said rotational speed is above said first predetermined value.

2. A starting apparatus for an engine according to claim 1, further comprising:

a temperature sensor for detecting coolant temperature of said engine, and

wherein said controller further includes;

fourth means for varying said torque of said motor operation in accordance with said coolant temperature of said engine.

3. A starting apparatus for an engine according to claim 1, wherein said controller further includes:

fifth means for instructing to said power control means so that said torque generated by said motor operation is gradually increased when said rotational speed is below said second predetermined value.

4. A starting apparatus for an engine comprising:

a generator/motor capable of starting an engine by motor operation when energized by energization current and generating electric power by generator operation when driven by said engine;

speed detecting means for detecting a rotational speed of said engine;

a power control unit for switching operational mode of said generator/motor between said motor operation and said generator operation; and

controller for controlling said power control unit in response to said rotational speed detected by said speed detecting means,

wherein said controller controls said power control unit so that said generator operation of said generator/motor is performed for a predetermined time period when said rotational speed of said engine reaches a predetermined value immediately after completion of said engine starting by said motor operation.

5. An engine starting apparatus comprising:

motor means for applying torque to an engine when energized to start said engine;

speed detecting means for detecting a rotational speed of said engine; and

electric power control means for controlling torque generated by said motor means, said control means reducing said torque of said motor means when said detected engine speed rises to a first predetermined speed.

6. An engine starting apparatus according to claim 5, wherein said control means stops energization of said motor means when said detected engine speed rises to a second predetermined speed higher than said first predetermined speed.

7. An engine starting apparatus according to claim 5, wherein said torque of said motor operation is varied in accordance with a coolant temperature of said engine and a crank angle of said engine.

8. An engine starting apparatus according to claim 5, wherein said motor means includes generator/motor which performs motor operation to produce torque when energized and generator operation when applied with torque from said engine.

9. An engine starting apparatus according to claim 8, wherein said generator/motor is switched to said generator operation when said detected engine speed rises to an idling speed.

10. An engine starting apparatus according to claim 9, wherein said control means stops energization of said generator/motor when said detected engine speed rises to a predetermined speed lower than said idling speed.

11. An engine starting apparatus according to claim 9, wherein said generator operation is limited to a first predetermined time period from initiation of said generator operation.

12. An engine starting apparatus according to claim 9, wherein said generator operation is disabled after a second predetermined time period has passed after turning on of an ignition switch.

13. A starting apparatus for an engine comprising:

a generator/motor capable of starting an engine by motor operation when energized by energization current and generating electric power by generator operation when driven by said engine;

speed detecting means for detecting a rotational speed of said engine;

a power control unit for switching operational mode of said generator/motor between said motor operation and said generator operation; and

controller for controlling said power control unit in response to said rotational speed detected by said speed detecting means,

wherein said controller includes;

first means for stopping said motor operation when said rotational speed reaches a first predetermined value before the starting of said engine has completed; and

second means for performing said generator operation for a predetermined time when said rotational speed reaches a second predetermined value which is higher than said first predetermined value, if a predetermined time period has not passed since said engine began to start.

14. A starting apparatus for an engine according to claim 13, wherein said controller controls said power control unit so that said power control unit gradually reduces torque in said motor operation when said rotational speed rises to a third predetermined value which is lower than said first predetermined value.

15. A starting apparatus for an engine according to claim 13, wherein said power control unit controls torque of said motor operation in accordance with a coolant temperature of said engine.