SPECIFICATION

Hybrid Vehicle

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a hybrid vehicle, in particular a hybrid rail vehicle, which has an internal combustion engine and an additional electric drive.

A diesel engine comes into consideration in particular as the internal combustion engine, whereas a conventional electric drive of a rail vehicle, with the (main) components required for it and supplied with electrical power by way of a contact wire, is provided in particular as the electric drive.

It is known that, as from a certain overall size, internal combustion engines cannot be started at any temperature, and so at extreme temperatures the internal combustion engine must be preheated for this purpose.

Document DE 10 2018 207 852 A1 describes heating of a diesel engine of a hybrid vehicle. In this case, a thermal transfer from components of the contact-wire-based electric drive to components of the internal combustion engine has been provided in order to achieve sufficient preheating of the internal combustion engine.

If the hybrid vehicle uses the internal combustion engine to operate, the internal combustion engine and its assigned components or units (for example cooling provided for the diesel engine) are engaged in energy conversion, that is to say are operated correspondingly and partly heated. Those components of the hybrid vehicle that are intended for the contact-wire-based electric drive are not then involved in the energy conversion and remain cold.

At extreme temperatures or in corresponding snowy situations in winter, this could lead to icing or accumulations of snow on highly relevant components of the electric drive. In particular, a cooling system of the main transformer would be adversely affected by this if it were integrated in the underfloor area of the hybrid vehicle.

A changeover from the (diesel-based) internal combustion engine drive to the contact-wire-based electric drive could be put at risk if ice forms on the surface of fans of the cooling system provided for the main transformer, and they consequently cannot take in sufficient air for the required cooling. As a consequence, the cooling water used for cooling would heat up in such a way that the contact-wire-based drive would be put at risk.

SUMMARY OF THE INVENTION

DE 10 2017 108 832 A1 discloses a vehicle temperature control system for a hybrid vehicle.

The object of the present invention is to provide an improved hybrid vehicle with respect to the changing of the drive at extreme temperatures, with greater availability and operational reliability of the system components.

This object is achieved by the features as claimed.

Advantageous developments are specified by the dependent claims.

The present invention relates to a hybrid vehicle which has as a changeable drive an internal combustion engine and an electric drive. The internal combustion engine has a cooling circuit which has a heat transfer medium and a cooler and is referred to hereinafter as the first cooling circuit. The first cooling circuit is intended to take up heat from the internal combustion engine by means of the heat transfer medium and conduct it to the cooler in order to make it possible for the heat to be dissipated to the surrounding area of the internal combustion engine or the hybrid vehicle.

The electric drive has a cooling circuit which has a heat transfer medium and a cooler and is referred to as the second cooling circuit. The second cooling circuit is intended to conduct heat from components of the electric drive by means of the heat transfer medium to the cooler in order to make it possible for the heat to be dissipated to a surrounding area of the electric drive or the hybrid vehicle.

Arranged between the first cooling circuit and the second cooling circuit is a preheating circuit, which is connected to the first cooling circuit by way of two connecting points in such a way that the heat transfer medium of the first cooling circuit at least partially circulates through components of the preheating circuit.

The preheating circuit and the second cooling circuit have a heat coupler as a common component. The preheating circuit and the second cooling circuit are thermally coupled to one another by the common heat coupler in such a way that heat can be controllably exchanged between the heat transfer media of the two cooling circuits.

The preheating circuit has an electrical auxiliary heater, which is connected in series with the heat coupler, and so the electrical auxiliary heater is likewise flowed through by the heat transfer medium of the first cooling circuit. The electrical auxiliary heater is in this case arranged and designed in such a way that heat generated by it can be transferred as and when required into at least one of the two cooling circuits.

In an advantageous refinement, the first cooling circuit has cylinders of the internal combustion engine, the heat transfer medium, a collection tank, a distribution tank, an adjustable thermostatic valve, the cooler, a pump and an engine-oil cooler. Seen in the direction of flow of the heat transfer medium of the first cooling circuit, these are connected in such a way:that the heat transfer medium is directed from the distribution tank to the cylinders in a divided manner to carry out cylinder cooling,that, after passing the cylinders, the heat transfer medium is collected by the collection tank,that the heat transfer medium either passes from the collection tank by way of the thermostatic valve and by way of the cooler to the pump or that the heat transfer medium passes from the thermostatic valve directly to the pump, andthat the heat transfer medium passes from the pump by way of the engine-oil cooler back to the distribution tank.

According to the invention, the second cooling circuit has in addition to the heat transfer medium the components of the electric drive, the heat exchanger, a pump and the fan, which, seen in the direction of flow of the heat transfer medium, are connected in such a way:that the heat transfer medium passes from the drive components to the pump,that the heat transfer medium passes on the one hand from the pump directly to the fan and on the other hand from the pump by way of the heat exchanger to the fan, andthat the heat transfer medium passes from the fan back to the drive components, in order to take over the heat produced during the operation of the drive or the drive components.

In an advantageous refinement, a first connecting point is arranged, seen in the direction of flow of the heat transfer medium of the first cooling circuit, functionally ahead of the input of the pump, and so in every position of the thermostatic valve the first connecting point is in contact with the heat transfer medium and at least partially feeds it to the preheating circuit. A second connecting point is arranged between the engine-oil cooler and the distribution tank of the first cooling circuit, in order to feed the branched-off heat transfer medium of the first cooling circuit back to it.

In an advantageous refinement, the preheating circuit has a first series connection with the functionality of a preheating device. The first series connection is connected on the input side to the first connecting point and on the output side to the second connecting point, and so the branched-off heat transfer medium of the first cooling circuit passes from the first connecting point by way of the first series connection to the second connecting point.

The first series connection has, following one another in series, a pump, a heating element and a check valve. The heating element can be used to generate heat for intended operation, or starting up, of the internal combustion engine, which is fed to components of the internal combustion engine, in particular to the fan of the first cooling circuit, as and when required by way of the heat transfer medium.

In an advantageous refinement, the preheating circuit has a second series connection with the functionality of a preheating device. The first series connection is connected on the input side to the first connecting point and on the output side to the second connecting point, and so the branched-off heat transfer medium of the first cooling circuit passes from the first connecting point by way of the second series connection to the second connecting point.

The second series connection has, following one another in series, the electrical auxiliary heater and the heat exchanger of the preheating circuit.

The electrical auxiliary heater is used to generate heat for intended operation, or starting up, of the internal combustion engine or the electric drive.

The heat of the auxiliary heater optionally passes either by way of the heat transfer medium of the first cooling circuit to components of the internal combustion engine, in particular to the fan of the first cooling circuit (KK1), for heating. As an alternative to this, the heat of the auxiliary heater passes by way of the heat exchanger and by way of the heat transfer medium of the second cooling circuit to components of the electric drive, in particular to the fan (206) of the second cooling circuit (KK2), for heating.

In an advantageous refinement, the electric auxiliary heater is supplied with power from an additional secondary winding of the main transformer of the hybrid vehicle or from a backup electrical system on board the hybrid vehicle, and so it can be operated and switched on and off even when the hybrid vehicle is at a standstill.

In an advantageous refinement, to achieve the functionality of the preheating device, the second series connection has in addition to the electrical auxiliary heater and the heat exchanger a pump, a check valve and a switchable valve, which are connected in such a way that, seen in the direction of flow, the branched-off heat transfer medium passes from the first connecting point by way of the pump to the check valve, that, seen in the direction of flow, the branched-off heat transfer medium passes from the check valve by way of the heat exchanger to the electrical preheater and from there to the second connecting point.

The switchable valve is arranged parallel to the pump and the check valve, and so the latter can be bridged by way of the switchable valve. In a first switching state of the switchable valve, the heat transfer medium then passes from the first connecting point by way of the pump and by way of the downstream check valve to the heat exchanger. In a second switching state of the switchable valve, the heat transfer medium passes from the first connecting point directly to the heat exchanger, the check valve preventing the heat transfer medium from circulating through the preheating device by way of the control of the pump.

In an advantageous refinement, the hybrid vehicle is a hybrid rail vehicle in which the internal combustion engine is a diesel engine and in which the electric drive is an electric drive which is supplied with electrical power by way of a contact wire.

The present invention offers the advantage of increasing availability of the hybrid vehicle under extreme weather conditions in winter. A reliable changeover between the two drives is ensured even at very low temperatures.

The present invention makes it possible for components (for example fans) to be de-iced in a way that does not require any additional operating substances and is therefore emission-neutral.

The ecological fingerprint of the hybrid vehicle is further improved by the electrical auxiliary heater, because in contact-wire-based operation no fuel is used for the preheating.

With the electrical auxiliary heater, the present invention also offers the advantage that electrical auxiliary heating achieved with it can even take place at a standstill, for example when stopping at stations, this auxiliary heating operating with very little noise.

To sum up, the present invention provides an improved hybrid vehicle with respect to the changing of the drive at extreme temperatures, with greater availability and operational reliability of the system components, without at the same time adversely influencing the ecological fingerprint of the hybrid vehicle.

