Method for Operating a Powertrain in a Motor Vehicle

• US 20150088395A1
• Filed: 12/03/2014
• Published: 03/26/2015
• Est. Priority Date: 06/04/2012
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: DOUBEK, Peter
• Granted Patent: US 9,316,274 B2
• Time in Patent Office: Days
• US Class Current: 701/67
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 2030/1809 Without torque flow between driveshaft and engine, e.g. with clutch disengaged or transmission in neutral
• CPC Class Codes: B60W 2510/08 Electric propulsion units
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2710/065 Idle condition
• CPC Class Codes: B60W 2710/0655 Coasting condition
• CPC Class Codes: B60W 30/18072 Coasting
• CPC Class Codes: B60W 50/0097 Predicting future conditions
• CPC Class Codes: F16D 48/06 Control by electric or electronic means, e.g. of fluid pressure
• CPC Class Codes: Y02T 10/60 Other road transportation technologies with climate change mitigation effect
• CPC Class Codes: Y02T 10/84 Data processing systems or methods, management, administration

Abstract

A method is provided for operating a powertrain in a motor vehicle, the powertrain having an internal combustion engine and components for coupling the internal combustion engine to the drive wheels of the motor vehicle in a controllable manner. The internal combustion engine is decoupled from the drive wheels if specified operating conditions are present while the motor vehicle is traveling in order to allow the vehicle to coast. Further, a rotational engine speed is set to a specified target idle speed. The target idle speed is specified in a variable manner depending on the situation.

Claims

1. A method for operating a motor vehicle powertrain having an internal-combustion engine and components for coupling the internal-combustion engine to drive wheels of the motor vehicle in a controllable manner, the method compromising the acts of:

when the motor vehicle is traveling, decoupling the internal-combustion engine from the drive wheels under predefined operating conditions in order for the motor vehicle to coast, wherein

a rotational engine speed of the internal-combustion engine is set to a predefined desired rotational idling speed, and

the predefined desired rotational idling speed is variably predefined as a function of a situation of the motor vehicle.

2. The method according to claim 1, further comprising the act of:

determining the predefined desired rotational idling speed as a function of an actual operating state of a generator coupled with the internal-combustion engine that generates current while the internal-combustion engine is still coupled with the drive wheels.

3. The method according to claim 2, wherein:

the actual operating state of the generator is an actually generated current of the generator, a temperature of the generator while the powertrain is still coupled, a temperature-specific stored characteristic generator curve, a generator type, and/or a generator type-specific stored characteristic generator curve.

4. The method according to claim 3, wherein by way of the determined predefined desired rotational idling speed, the actually generated current of the generator before the decoupling of the internal-combustion engine from the drive wheels continues to be provided.

5. The method according to claim 1, further comprising the act of:

when the internal-combustion engine is decoupled from the drive wheels, controlling the predefined desired rotational idling speed via an automatic rotational speed controller or a rotational speed controller.

6. The method according to claim 1, further comprising the acts of:

when the predefined operating conditions are present, determining the desired rotational idling speed and setting the rotational engine speed is to the determined desired rotational idling speed or a rotational speed dependent on the determined desired rotational idling speed when the determined desired rotational idling speed is within a predefined rotational idling speed window or when it is more than a predefined rotational idling speed threshold.

7. The method according to claim 6, wherein when the predefined operating conditions are present, decoupling of the internal-combustion engine with the drive wheels is not carried out when the determined desired rotational idling speed is not within a predefined rotational idling speed window or is not lower than a predefined rotational idling speed threshold.

8. The method according to claim 1, wherein when the predefined operating conditions are present, decoupling of the internal-combustion engine with the drive wheels is not carried out when a determined desired rotational idling speed is not within a predefined rotational idling speed window or is not lower than a predefined rotational idling speed threshold.

9. The method according to claim 1, wherein:

after the decoupling of the drive wheels, the method further comprises the acts of;

deactivating predefined electric power consuming devices, and/or

operating the predefined electric power consuming devices such that power consumption is reduced.