METHOD AND SYSTEM FOR OPERATING A MOTOR VEHICLE

Abstract

A motor vehicle can be powered by a combustion engine or an electric machine or both. Coolant is conveyed in the coolant circuit first to the electric machine before being conveyed from the electric machine to the combustion engine for cooling both the combustion engine and the electric machine. A cooling device adjusts a temperature of the coolant in the coolant circuit in such a way that the cooling device adjusts the coolant to a first temperature, when the motor vehicle is powered by the combustion engine, and to a second temperature which is less than the first temperature, when the motor vehicle is powered by the electric machine and the combustion engine.

Claims

1. A method, comprising: operating a motor vehicle by at least one of a combustion engine and an electric machine; conveying coolant in a common coolant circuit first to the electric machine before being conveyed from the electric machine to the combustion engine for cooling both the combustion engine and the electric machine; and adjusting a temperature of the coolant by a cooling device in the coolant circuit in such a way that the cooling device adjusts the coolant to a first temperature, when the motor vehicle is powered solely by the combustion engine, and to a second temperature which is less than the first temperature, when the motor vehicle is powered by the electric machine and the combustion engine.

2. The method of claim 1, further comprising operating a power electronics by the electric machine operably connected to the power electronics.

3. The method of claim 2, further comprising connecting the electric machine downstream of the power electronics, and conveying coolant first to the power electronics and then from the power electronics to the electric machine.

4. The method of claim 1, further comprising adjusting the coolant to a third temperature which is less than the second temperature, when the motor vehicle is powered solely by the electric machine.

5. A system for operating a motor vehicle, said system comprising: an electric machine; a combustion engine arranged downstream of the electric machine; a common coolant circuit for cooling both the combustion engine and the electric machine, said common coolant circuit being configured to first convey coolant to the electric machine before being conveyed from the electric machine to the combustion engine; and a cooling device disposed in the coolant circuit to adjust a temperature of the coolant in the coolant circuit in such a way that the cooling device adjusts the coolant to a first temperature, when the motor vehicle is powered solely by the combustion engine, and to a second temperature which is less than the first temperature, when the motor vehicle is powered by the electric machine and the combustion engine.

6. The system of claim 5, wherein the combustion engine and the electric machine are connected successively in the coolant circuit via a duct extending between the combustion engine and the electric machine.

7. The system of claim 5, further comprising a power electronics operated by the electric machine which is operably connected to the power electronics.

8. The system of claim 5, wherein the cooling device adjusts the coolant to a third temperature which is less than the second temperature, when the motor vehicle is powered solely by the electric machine.

9. A cooling system for a motor vehicle, said cooling system comprising: a coolant circuit for cooling an electric machine and a combustion engine arranged downstream of the electric machine, said coolant circuit being configured to first convey coolant to the electric machine before being conveyed from the electric machine to the combustion engine; and a cooling device disposed in the coolant circuit to adjust a temperature of the coolant in the coolant circuit in such a way that the cooling device adjusts the coolant to a first temperature, when the motor vehicle is powered solely by the combustion engine, and to a second temperature which is less than the first temperature, when the motor vehicle is powered by the electric machine and the combustion engine.

10. The cooling system of claim 9, wherein the cooling device adjusts the coolant to a third temperature which is less than the second temperature, when the motor vehicle is powered solely by the electric machine.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0018] Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which the sole FIG. 1 is a schematic representation of a system according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0019] The depicted embodiment is to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figure may not necessarily be to scale. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

[0020] Turning now to FIG. 1, there is shown a schematic representation of a system according to the present invention, generally designated by reference numeral 2, for powering a motor vehicle. The system 2 represents hereby a component of the motor vehicle and includes an electric machine 4 and a combustion engine 6 which can be used individually or jointly to power the motor vehicle. The electric machine 4 is operably connected to a power electronics 8 which is active, whenever the electric machine 4 is in operation.

[0021] The motor vehicle can be powered solely by the electric machine 4, or solely by the combustion engine 8, or in a hybrid operating mode in which both the electric machine 4 and the combustion engine 6 are operated to power the motor vehicle.

[0022] The system 2 includes a common single coolant circuit 10 to cool the electric machine 4 with associated power electronics 8 and the combustion engine 6. The coolant circuit 10 includes a cooling device 12 (or radiator) configured to adjust a temperature of coolant circulating in the coolant circuit 10. Moreover, the coolant circuit 10 includes a duct system with several ducts 14 via which coolant flows to the combustion engine 6 and the electric machine 4 with associated power electronics 8 and is conveyed by a pump 16 in the coolant circuit 10. The pump 16 is hereby positioned at a location upstream of the power electronics 8, with the electric machine 4 being arranged downstream of the power electronics 8 and with the combustion engine 6 being arranged downstream of the electric machine 4. The individual components are hereby connected by respective ducts 14 of the duct system.

[0023] The power electronics 8, the electric machine 4 and the combustion engine 6 are connected directly behind one another in a row in the coolant circuit 10 which further includes a valve 18 and a valve 20 which open and close in dependence on demand. When both valves 18, 20 are closed, the cooling device 12 is separated from the power electronics 8, the electric machine 4 and the combustion engine 6, so that no cooling takes place for these components. When the valves 18, 20 are both open, coolant, cooled by the cooling device 12, can be conveyed by the pump 16 through the ducts 14 of the coolant circuit 10 sequentially to the power electronics 8, the electric machine 4 and the combustion engine 6.

[0024] Thus, when the coolant circuit 10 is operated, coolant, cooled by the cooling device 12, is forced by and/or via the pump 16 to flow first to the power electronics 8, then to the electric machine 4, and then to the combustion engine 6.

[0025] When the motor vehicle is powered solely by the combustion engine 6, coolant is adjusted to a first temperature, whereas in a situation when the motor vehicle is powered by both the electric machine 4 and the combustion engine 6, coolant is adjusted to a second temperature which is less than the first temperature. When the motor vehicle is powered solely by the electric machine 4, coolant is adjusted to a third temperature which is less than the second temperature.

[0026] While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit and scope of the present invention. The embodiments were chosen and described in order to explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

[0027] What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and includes equivalents of the elements recited therein: