US 9,316,149 B2Granted

Method and control unit for operating a drive train of a hybrid vehicle

AssigneeZF Friedrichshafen AG

InventorsTobias Zollner, Bernd Allgaier, Clemens Kuhn, Patrick Peter, Lorenz Fehrenbach, Holger Bacher

Life of this patent

Estimating the term…

Loading patent…

Abstract

A method of operating a drive-train of a hybrid vehicle which comprises at least a hybrid drive with an internal combustion engine and an electric machine, an automatic or automated change-speed transmission connected between the hybrid drive and a drive output, and a clutch connected between the internal combustion engine and the electric machine. When starting the internal combustion engine from a purely electric driving mode, the clutch is initially disengaged. To start the internal combustion engine, the clutch is at least partially engaged and the internal combustion engine is drag-started by the electric machine, and, in parallel with starting the internal combustion engine, a downshift in the transmission is initiated once a rotational speed of the internal combustion engine reaches or exceeds an applicable threshold value.

Claims13

Dependent claims

A method of operating a drive-train of a hybrid vehicle, the drive-train comprising at least a hybrid drive comprising an internal combustion engine (1) and an electric machine (2), either an automatic or an automated change-speed transmission (3) being connected between the hybrid drive and a drive output (4), and a clutch (5) being connected between the internal combustion engine (1) and the electric machine (2), and the clutch (5), when starting the internal combustion engine (1) from a purely electric driving mode, being initially disengaged, the method comprising the steps of:

at least partially engaging the clutch (5) such that the clutch (5) transmits torque from the electric machine (2) to the internal combustion engine (1) in order to start the internal combustion engine (1),
drag-starting the internal combustion engine (1) via the electric machine (2),
in parallel with the starting of the internal combustion engine (1), once a rotational speed of the internal combustion engine either reaches or exceeds a threshold value, prior to completion of the starting of the internal combustion engine, initiating a downshift in the transmission (3), and
when the rotational speed of the internal combustion engine (1) either reaches or exceeds a defined threshold, sufficiently disengaging the clutch (5) at least so that the clutch no longer transmits any torque and the internal combustion engine (1) can run freely, and
engaging the clutch (5) and coupling the internal combustion engine (1) to the drive-train once a rotational speed of the internal combustion engine (1) either reaches or exceeds a rotational speed of the electric machine (2).

2 more elements

A control unit for operating a drive-train of a hybrid vehicle which, in order to start an internal combustion engine (1) of a hybrid drive from a purely electric driving mode, actuates an initially disengaged clutch (5), connected between the internal combustion engine (1) and an electric machine (2) of the hybrid drive, such that the clutch (5) is first at least partially engaged so as to drag-start the internal combustion engine (1) with the electric machine (2) of the hybrid drive,

the control unit controlling a transmission (3) such that a downshift is initiated in the transmission (3), in parallel with the starting of the internal combustion engine (1) and prior to completion of the starting of the internal combustion engine, when a rotational speed of the internal combustion engine (1) either reaches or exceeds an applicable threshold value, and the clutch is disengaged when the rotational speed of the internal combustion engine either reaches or exceeds a defined threshold, and
subsequently engaging the clutch to couple the internal combustion engine to the drive train once the rotational speed of the internal combustion engine either reaches or exceeds a rotational speed of the electric machine.

A method of operating a drive-train of a hybrid vehicle, the drive-train comprising an internal combustion engine, an electric machine, either an automatic or an automated change-speed transmission being connected in a flow of drive between the electric machine and a drive output, and a clutch being connected between the internal combustion engine and the electric machine, the method comprising the steps of:

driving the hybrid vehicle in a purely electric driving mode with the internal combustion engine turned off and the clutch disengaged;
at least partially engaging the clutch to transmit torque from the electric machine, via the clutch, to the internal combustion engine in order to drag-start the internal combustion engine with the electric machine,
in parallel with the drag starting of the internal combustion engine, before completing the drag starting of the internal combustion engine, initiating a downshift in the transmission once a rotational speed of the internal combustion engine either reaches or exceeds a threshold value;
and
when the rotational speed of the internal combustion engine either reaches or exceeds a defined threshold, at least partially disengaging the clutch to a point such that no torque is transferred by the clutch from the electric machine to the internal combustion engine
such that the internal combustion engine is free to run-up without transmitting torque;
and
subsequently re-engaging the clutch, once the rotational speed of the internal combustion engine either reaches or exceeds a rotational speed of the electric machine, to couple the internal combustion engine to the drive-train.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/978,154Filed 6 Dec 2011
Priority: DE 10 2011 002 74217 Jan 2011
Published: US 2013/0284125 A131 Oct 2013
Granted: 19 Apr 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification23 codes

F02B 63/04
Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices: for…
B60K 6/48
Characterised by the architecture of the hybrid electric vehicle: parallel type
B60W 10/06
Including control of propulsion units: including control of combustion engines
B60W 20/00
Control systems specially adapted for hybrid vehicles