Method for controlling an overrun condition of a hybrid vehicle and hybrid vehicle

• US 7,840,337 B2
• Filed: 10/13/2005
• Issued: 11/23/2010
• Est. Priority Date: 10/30/2004
• Status: Expired due to Fees

• Current Assignee: Skoda Auto A.S. (Volkswagen AG), Volkswagen AG
• Original Assignee: Skoda Auto A.S. (Volkswagen AG), Volkswagen AG
• Inventors: Holz, Matthias, Pott, Ekkehard, Zillmer, Michael, Prochazka, David
• Primary Examiner(s): Vo; Hieu T
• Application Number:
  US11/666,836
• Publication Number:
  US 20080227589A1
• Time in Patent Office: 1,867 Days
• Field of Search: 123/319, 123/325, 123/339.19, 180/65.1, 180/65.21, 180/65.28, 477/7, 477/14, 701/110, 701/114, 701/22
• US Class Current: 701/114
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/445 Temperature
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2710/0616 Position of fuel or air injector
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60W 2710/065 Idle condition
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: F02D 41/064 at cold start F02D41/067 takes precedence
• CPC Class Codes: F02D 41/123 the fuel injection being cut-off
• CPC Class Codes: F02D 41/126 transitional corrections at the end of the cut-off period
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility

Abstract

A method is for controlling an overrun condition in a hybrid vehicle having a combustion engine and additionally at least one electric motor as well as an overrun fuel cutoff, which interrupts a fuel supply to the combustion engine when the vehicle is in an overrun condition and restores the fuel supply when the combustion engine reaches or falls below a restoring speed. At least in a combustion engine at operating temperature, the fuel supply is restored at a restoring speed of at most 200 min⁻¹, e.g., at most 100 min⁻¹ above an idling speed of the combustion engine. The restoring speed may be in the range of the idling speed or only slightly above the latter. The restoring speed is thus clearly lowered as compared to the usual restoring speeds and extends the overrun fuel cutoff phases and thus reduces fuel consumption.

Claims

1. A method for controlling an overrun condition of a hybrid vehicle having a combustion engine, at least one electric motor and an overrun fuel cutoff configured to cut off a fuel supply to the combustion engine when the vehicle is in an overrun condition and to restore the fuel supply when the combustion engine at least one of (a) reaches and (b) falls below a restoring speed, comprising:

restoring the fuel supply, at least for the combustion engine at operating temperature, at a restoring speed of at most 200 rpm above an idling speed of the combustion engine;

superimposing a torque of the electric motor on the combustion engine as a support for at least one of (a) decelerating the combustion engine and (b) adjusting the combustion engine to the idling speed at least one of (a) before, (b) during and (c) following the restoration of the fuel supply to the combustion engine;

wherein the superimposing includes alternately superimposing positive and negative torques of the electric motor on the combustion engine for at least one of (a) decelerating the combustion engine and (b) adjusting the combustion engine to the idling speed.

2. The method according to claim 1, wherein the restoring speed is one of (a) at most 150 rpm, (b) at most 100 rpm and (c) at most 50rpm above the idling speed.

3. The method according to claim 1, wherein the restoring speed is one of (a) at most 20 rpm above the idling speed and (b) the idling speed.

4. The method according to claim 1, wherein at least one of (a) the idling speed and (b) the restoring speed is independent of a temperature of the combustion engine.

5. The method according to claim 1, further comprising superimposing the torque of the electric motor on the combustion engine for building up a torque reserve of an idling combustion engine that is not passed on to a crankshaft.

6. The method according to claim 1, further comprising, following the restoration of the fuel supply, adjusting a torque of the combustion engine in an efficiency-optimized manner to a torque required for setting the idling speed without building up a torque reserve.

7. The method according to claim 1, wherein the torque of the electric motor is not activated until and is activated only when a speed of the combustion engine falls below a permissible lower speed threshold, which is at least one of (a) smaller than or equal to the restoring speed and (b) smaller than the idling speed.

8. The method according to claim 1, wherein the torque of electric motor is not activated until and is activated only when a difference between an actual speed characteristic and a setpoint speed characteristic exceeds a difference threshold value.

9. The method according to claim 1, wherein the superimposing includes superimposing alternating positive and negative torques of the electric motor prior to the restoration of the fuel supply to the combustion engine.

12. The hybrid vehicle according to claim 10, wherein the hybrid vehicle is configured to perform the method according to claim 1.

10. A hybrid vehicle, comprising:

a combustion engine;

at least one electric motor;

an overrun fuel cutoff control configured to cut off a fuel supply to the combustion engine when the vehicle is in an overrun condition and to restore the fuel supply when the combustion engine at least one of (a) reaches and (b) falls below a restoring speed, the overrun fuel cutoff control configured to restore the fuel supply, at least for the combustion engine at operating temperature, at a restoring speed of at most 200 rpm above an idling speed of the combustion engine, the overrun fuel cutoff control configured to superimpose alternately positive and negative torques of the electric motor on the combustion engine as a support to at least one of (a) decelerate the combustion engine and (b) adjust the combustion engine to the idling speed at least one of (a) before, (b) during and (c) following restoration of the fuel supply to the combustion engine.

11. The hybrid vehicle according to claim 10, wherein the overrun fuel cutoff control includes a program code stored at least one of (a) in an engine control unit and (b) in a separate control unit.