Auxiliary machine drive system of automatic engine stop-restart system equipped automotive vehicle

• US 20030173124A1
• Filed: 02/24/2003
• Published: 09/18/2003
• Est. Priority Date: 03/15/2002
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Okada, Hiroshi, Iwao, Shuji
• Granted Patent: US 6,793,059 B2
• Time in Patent Office: Days
• US Class Current: 180/65.2
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 25/02 directly from an engine shaft
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: F02N 11/003 said electric motor being also used as a drive for auxiliaries, e.g. for driving transmission pumps or fuel pumps during engine stop
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 15/022 the starter comprising an intermediate clutch
• CPC Class Codes: F16D 27/112 with flat friction surfaces, e.g. discs
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

In an auxiliary machine drive system of an automatic engine stop-restart system equipped automotive vehicle capable of automatically stopping or restarting an engine depending on vehicle operating conditions, an electromagnetic clutch is disposed between the engine and at least one auxiliary machine for connecting and disconnecting an engine crankshaft to and from the auxiliary machine. An electromagnetic clutch control unit deenergizes the electromagnetic clutch at least in an engine running state, and energizes it only when a predetermined energizing condition is satisfied. The predetermined energizing condition includes at least an engine stopped state. The electromagnetic clutch is comprised of a normally-engaged electromagnetic clutch that is engaged when deenergized, and disengaged when energized.

Claims

1. An auxiliary machine drive system of an automatic engine stop-restart system equipped automotive vehicle capable of automatically stopping or restarting an engine depending on vehicle operating conditions, comprising:

an electromagnetic clutch disposed between the engine and at least one auxiliary machine for connecting and disconnecting a crankshaft of the engine to and from the auxiliary machine;

an electromagnetic clutch control unit deenergizing the electromagnetic clutch at least when the engine is running, and energizing the electromagnetic clutch only when a predetermined energizing condition is satisfied, the predetermined energizing condition including at least a stopped state of the engine; and

the electromagnetic clutch comprising a normally-engaged electromagnetic clutch that is engaged when deenergized, and disengaged when energized.

2. The auxiliary machine drive system as claimed in claim 1, further comprising:

an electric motor connected to the auxiliary machine to drive the auxiliary machine; and

the electric motor serving as an engine start-up motor that is connected to the crankshaft of the engine via the electromagnetic clutch when automatically restarting the engine.

3. The auxiliary machine drive system as claimed in claim 1, wherein:

the predetermined energizing condition includes a condition that a requirement for driving the auxiliary machine by means of the electric motor is present.

4. The auxiliary machine drive system as claimed in claim 2, further comprising:

a brake control unit executing a wheel-brake-cylinder pressure building-up and holding mode in which a braking force of the vehicle is built up above and held at a predetermined value, when energizing and disengaging the electromagnetic clutch.

5. An auxiliary machine drive system of an automatic engine stop-restart system equipped automotive vehicle capable of automatically stopping or restarting an engine depending on vehicle operating conditions, comprising:

a motor generator connected to at least one auxiliary machine to drive the auxiliary machine;

the motor generator serving as an engine start-up motor that is connected to a crankshaft of the engine via the electromagnetic clutch when automatically restarting the engine;

an electromagnetic clutch disposed between the engine and each of the auxiliary machine and the motor generator for connecting and disconnecting the crankshaft of the engine to and from each of the auxiliary machine and the motor generator;

a wrapping connector by which the auxiliary machine and the motor generator are directly connected to each other;

an electromagnetic clutch control unit deenergizing the electromagnetic clutch at least when the engine is running, and energizing the electromagnetic clutch only when a predetermined energizing condition is satisfied, the predetermined energizing condition including at least a stopped state of the engine; and

the electromagnetic clutch comprising a normally-engaged electromagnetic clutch that is engaged when deenergized, and disengaged when energized.

6. The auxiliary machine drive system as claimed in claim 5, wherein:

the electromagnetic clutch is attached to the crankshaft of the engine; and

the wrapping connector comprises a power-transmission belt wound on an axial end of the crankshaft, an axial end of a rotational shaft of the auxiliary machine, and an axial end of a rotational shaft of the motor generator.

7. The auxiliary machine drive system as claimed in claim 5, wherein:

the electromagnetic clutch is attached to a rotational shaft of the motor generator; and

the wrapping connector comprises a first power-transmission belt wound on an axial end of the rotational shaft of the motor generator and an axial end of a rotational shaft of the auxiliary machine, and a second power-transmission belt wound on an axial end of the crankshaft and the axial end of the rotational shaft of the motor generator.

8. An auxiliary machine drive system of an automatic engine stop-restart system equipped automotive vehicle capable of automatically stopping or restarting an engine depending on vehicle operating conditions, comprising:

an electromagnetic clutch disposed between the engine and at least one auxiliary machine for connecting and disconnecting a crankshaft of the engine to and from the auxiliary machine;

a control means for deenergizing the electromagnetic clutch at least when the engine is running, and for energizing the electromagnetic clutch only when a predetermined energizing condition is satisfied, the predetermined energizing condition including at least a stopped state of the engine; and

the electromagnetic clutch comprising a normally-engaged electromagnetic clutch that is engaged when deenergized, and disengaged when energized.

9. A method for executing automatic engine stop-restart control functions for an auxiliary machine drive system of an automatic engine stop-restart system equipped automotive vehicle capable of automatically stopping or restarting an engine depending on vehicle operating conditions and having an electromagnetic clutch disposed between the engine and at least one auxiliary machine for connecting and disconnecting a crankshaft of the engine to and from the auxiliary machine and a motor generator connected to the auxiliary machine to drive the auxiliary machine, the method comprising:

determining whether a specified automatic stop condition of the engine is satisfied;

automatically stopping the engine when the specified automatic stop condition of the engine is satisfied;

determining whether a requirement for driving the auxiliary machine by means of the motor generator is present;

energizing and disengaging the electromagnetic clutch when the specified automatic stop condition of the engine is satisfied and the requirement for driving the auxiliary machine by means of the motor generator is present;

driving the auxiliary machine by means of the motor generator when the electromagnetic clutch is energized and disengaged when the specified automatic stop condition of the engine is satisfied and the requirement for driving the auxiliary machine by means of the motor generator is present;

determining whether a specified automatic restart condition of the engine is satisfied;

deenergizing and engaging the electromagnetic clutch when the specified automatic restart condition of the engine is satisfied; and

automatically restarting the engine by driving the crankshaft by means of the motor generator and by cranking the engine when the specified automatic restart condition of the engine is satisfied.

10. The method as claimed in claim 9, further comprising:

executing a wheel-brake-cylinder pressure building-up and holding mode in which a braking force of the vehicle is built up above and held at a predetermined value, when energizing and disengaging the electromagnetic clutch; and

canceling the wheel-brake-cylinder pressure building-up and holding mode after the engine has been automatically restarted.