WO2006125565A1 - Mechatronic coolant pump-drive connection - Google Patents

Abstract

Disclosed is a drive unit of a motor vehicle comprising at least one combustion engine (12) for advancing the motor vehicle and a cooling apparatus for ensuring adequate cooling of a drive unit with as little effort and especially as little space as possible. The cooling apparatus encompasses at least one coolant circuit (14) in which at least one coolant pump (1) is disposed. Said coolant pump (1) is equipped with a coupling to the combustion engine (12) and at least one electric motor (7) while a free-running device (6) is provided for the coupling.

Description

 Mechatronic coolant pump drive connection

The invention relates to a drive unit of a motor vehicle with a cooling device and an associated cooling method.

It is generally known to drive a cooling device via an output of the drive unit in a drive unit of a motor vehicle.

Object of the present invention is to ensure in different operating conditions of a drive unit of a motor vehicle needs-based cooling with the least possible effort and in particular small space requirement.

This object is achieved by a drive unit with the features of claim 1 and a cooling method with the features of claim 19. Advantageous embodiments and further developments are specified in the respective dependent claims.

In a drive unit according to the invention of a motor vehicle having at least one internal combustion engine for propulsion of the motor vehicle and a Kühlvor- device having at least one coolant circuit in which at least one coolant pump is arranged, the coolant pump has a coupling with the internal combustion engine and at least one electric motor, wherein a Freewheel is provided for the coupling.

The internal combustion engine is, for example, an internal combustion engine operating according to the Otto or Diesel principle.

The cooling device with the at least one coolant circuit is preferably provided for cooling both the internal combustion engine and a further drive or auxiliary unit. However, it may also be provided, only the

Internal combustion engine or just to cool the other drive or auxiliary unit with the cooling device. In particular, the cooling device has at least one heat exchanger.

The coolant pump is preferably a mechanical coolant pump. Particularly preferred is a water pump. However, other types of pumps may be used. As a coupling, for example, a mechanical coupling to a drive shaft of the coolant pump is provided. However, instead of a mechanical coupling, for example, an electromagnetic drive connection can be provided. Furthermore, a coupling may include a signaling link. In particular, a coupling can also include several, in particular, the above embodiments. For example, a coupling between the electric motor and the coolant pump may be configured differently to a coupling between the internal combustion engine and the coolant pump.

The freewheel is preferably configured such that a drive torque can be transmitted by means of the coupling in a drive rotational direction of the coolant pump and a torque acting counter to this drive rotational direction is interrupted by coupling. The driving rotational direction of the coolant pump is that which is required to convey the coolant in the coolant circuit in a designated direction. In particular, this makes it possible, for example, for a rotational speed of a drive shaft of the coolant pump to be greater than a rotational speed, for example of a traction sheave arranged on the latter, which is driven by the internal combustion engine. Advantageously, the coolant pump can be driven by means of the electric motor without the internal combustion engine having to have a rotational speed. Furthermore, advantageously, a speed of the coolant pump can be set independently of a rotational speed of the internal combustion engine. In a further development can also be provided to use torques of the internal combustion engine and electric motor together to drive the coolant pump. Particularly preferably, the electric motor can be dimensioned smaller compared to an otherwise comparable arrangement of a cooling device with, however, only electric motor-driven coolant pump. For example, an electric motor with a lower than in this case otherwise to be provided nominal power can be used. Accordingly, in particular, a lower current for the drive of the electric motor can be provided in comparison to a purely electrical cooling to be provided. For example, an electric motor with a power of about 1.5 kW may be provided when using a vehicle electrical system voltage of 12V. In one embodiment, an internal combustion engine which is not optimized with regard to a pressure loss of the cooling system of the internal combustion engine can preferably be used in the drive unit. In particular, a redesign of the engine or components of the cooling system is thereby reduced or avoided. In one embodiment, it is provided that the drive unit is a hybrid drive unit, which comprises at least one electric drive unit for propulsion of the motor vehicle. The electric drive unit is preferably an electric motor in conjunction with an electrical energy store. For example, this is a fuel cell and / or a battery or an accumulator. Preferably, the drive unit comprises a common coolant circuit for cooling both the internal combustion engine and the electric drive unit. However, it can also be provided to cool only the internal combustion engine or only the electric drive unit with the cooling device.

According to a development, the coupling comprises a first drive connection with the internal combustion engine and a second drive connection with an electric motor, wherein by means of the freewheeling at least one transmission of a counter to the driving direction of the coolant pump torque acting through the first drive connection can be interrupted.

As a first drive connection, for example, a mechanical drive connection to a drive shaft of the coolant pump is provided. Instead of a mechanical drive connection, however, an electromagnetic drive connection can also be provided, for example. Similarly, this applies to the second drive connection. First and second drive connection can act, for example, on a same drive shaft of the coolant pump. However, it may also be provided a coolant pump with two separate drive shafts for the first and the second drive connection.

The freewheel can be permanently activated in a first variant.

In a further variant it is provided that the freewheel is mechanically switchable. For example, a pawl or the like is activated by means of at least one mechanical actuating means.

According to another embodiment, the freewheel is electrically switchable. In this case, a circuit is effected in particular electromagnetically, for example by means of at least one electromagnet, or electromechanically, for example by means of at least one adjusting means. In a preferred embodiment, it is provided that the freewheel is both freewheeling counter and in the driving direction of rotation switchable. When the freewheel is activated, torques are then no longer transferable in both directions, preferably by the internal combustion engine. Accordingly, the coolant pump can be operated completely uninfluenced by the first drive connection and thus by the internal combustion engine. Preferably, the coolant pump may be used for temperature control using such a mode. For example, a speed of the coolant pump can be reduced in a cold start phase.

The freewheel is in a first variant, a pawl freewheel. For example, a pawl freewheel is arranged on a drive shaft of the coolant pump. A freewheel ring of the KNN kenfreilaufes is connected, for example, with a drive belt of an internal combustion engine. Instead of a coaxial freewheel arrangement may also be provided a freewheeling arrangement in the axial direction, for example by means of a provided with a saw tooth face under a correspondingly opposite pawl arrangement.

In a further variant, the freewheel is a sprag freewheel. In a non-switchable variant, a clamping between an outer freewheel ring and a drive shaft concentrically arranged therein is achieved by means of a clamping element, for example, depending on a direction of rotation. Similarly, a roller freewheel can be used.

In another embodiment, the freewheel comprises a clutch with an adjustable slip. Preferably, a slip can be continuously adjusted between completely slip-free and completely free from drive torque transmission. For example, a so-called viscous coupling is used. Furthermore, an electromagnetic clutch may be provided.

The first drive connection is in a preferred embodiment, a mechanical connection. For example, the first drive connection is selected from the group consisting of chain drive, belt drive and / or gear drive. Preferably, the first drive connection between a driven axle of the internal combustion engine and a drive shaft of the coolant pump is provided. For example, a drive is effected by means of gears arranged directly on the axles. Furthermore, the drive can be effected by means of a chain drive and corresponding sprockets. As well the drive can be designed by means of a belt drive and corresponding drive wheels.

According to a development it is provided that the first drive connection comprises a drive pulley. This is driven for example by a V-belt of the internal combustion engine.

It is particularly useful if the freewheel is integrated into the drive pulley. In this case, the drive disk preferably corresponds in terms of its dimensions essentially to a drive disk provided in an ordinary internal combustion engine for driving a coolant pump.

According to another idea, the electric motor is arranged on a drive shaft of the coolant pump and has at least one torque support. In particular, an output shaft of the electric motor forms the drive shaft of the coolant pump. Accordingly, both shafts can also be connected to a fixed coupling. The torque support is attached, for example, to a housing of the internal combustion engine. Furthermore, a fastening can be provided, for example, on the coolant pump itself.

In a further embodiment, it is provided that the electric motor is integrated in the pulley. For this purpose, for example, a stator and a rotor of the electric motor can be arranged concentrically on the drive shaft of the coolant pump and have a pawl lock counter to the drive rotational direction of the coolant pump. Preferably, the rotational speeds of the electric motor and the drive can be added by the internal combustion engine so.

An efficiency of the cooling system is improved in an expedient development if the coolant circuit comprises at least one additional switchable valve. For example, at least part of the coolant circuit can thereby be deactivated. In particular, when the coolant circuit is reduced, an increased coolant flow rate can be achieved. Furthermore, an additional switchable valve is provided, for example, to ensure demand-based cooling of an auxiliary unit or the like. In particular, a so-called split-cooling method is provided, according to which, for example, depending on the circuit of the valve or the valves selected areas of the drive unit to be cooled. For example, a cooling of the cylinder head can be activated or deactivated. A switching of the Valve can be done, for example, based on at least one thermal switch. Furthermore, a switching of a valve can take place for example by means of a motor control. Switching may also include partial opening or closing.

It is particularly expedient if the coolant circuit comprises at least one switchable branch to a cabin heater. Preferably, depending on the temperature of the internal combustion engine and a cabin temperature, a demand-based distribution of a heat flow is made in a vehicle cabin.

A drive unit, in particular a hybrid drive unit according to at least one of the above-described embodiments, may comprise a plurality of coolant pumps. In a preferred embodiment, the coolant circuit comprises exactly one coolant pump.

The invention further relates to a cooling method of a drive unit, in particular according to one of the preceding embodiments, which comprises at least one internal combustion engine, wherein a coolant for cooling the drive unit in at least one coolant circuit of the drive unit is circulated by means of at least one coolant pump, which via a first drive connection via a freewheel is driven by the internal combustion engine, wherein the freewheel is used when the coolant pump is driven in addition to or instead by means of at least one electric motor or is not driven.

The freewheel is in particular designed such that a transmission of a counter to the driving direction of rotation of the coolant pump torque acting through the first drive connection can be interrupted. In particular, the rotational speed of the coolant pump may exceed a rotational speed of the drive by the internal combustion engine. Particularly expedient, for example, after operation in a first phase under high load and subsequent operation in a second phase at low speeds of the internal combustion engine, a temperature increase prevented by reheating, for example, by increasing the speed of the coolant pump in the second phase by means of the electric motor, at least for a transitional period becomes. Furthermore, at higher load of the internal combustion engine, for example, a mountain or trailer ride improved cooling can be achieved.

According to a further embodiment, the drive unit is a hybrid drive unit, in particular according to one of the preceding embodiments, which at least an internal combustion engine and at least one electric drive unit summarizes, wherein a coolant for cooling the internal combustion engine and / or the electric drive unit in at least one coolant circuit of the hybrid drive unit is circulated by means of at least one coolant pump, which is driven via a first drive connection via a freewheel from the internal combustion engine wherein the freewheel is used when the coolant pump is driven in addition to or instead of at least one electric motor or is not driven at all.

Activation of the freewheel can be done especially when exceeding or falling below a predetermined speed. The predefinable speed is set, for example, fixed. In another variant, however, the speed can also be preset by a motor control time variable. In particular, the predeterminable speed is dimensioned such that sufficient cooling of the drive unit, which is in particular a hybrid drive unit, is ensured. Preferably, a speed of the coolant pump is adjusted by means of the electric motor.

In an advantageous embodiment, it is provided that the coolant pump is deactivated when the engine is running by means of a circuit of the freewheel. For this purpose, in particular the rotational speed of the electric motor and thus the rotational speed of the coolant pump is set to zero revolutions. A circuit of the freewheel is carried out in particular in both directions of rotation. Preferably, a forced-flow coolant flow is completely prevented in such a circuit of the freewheel and a deactivation of the coolant pump. Preferably can be dispensed with a valve for switching or control of the coolant circuit. In particular, however, at least one valve for switching or controlling the coolant circuit can also be provided. A deactivation of the coolant pump takes place, for example, temporarily, in order to allow in particular an increase in a temperature of the drive unit. This may be advantageous, for example, in a cold start phase.

In another expedient embodiment, at least one valve in the coolant circuit is at least partially opened or closed as a function of a rotational speed of the internal combustion engine and / or a temperature. A control of the valve, for example, by means of a thermal switch or by means of a motor control. Preferably, a needs-based temperature distribution and / or a demand-based distribution of heat flow is improved. Particularly expediently, an output from the internal combustion engine to the coolant pump drive power is controlled. For example, a required on-demand cooling performance is determined based on an engine control. Depending on this determined cooling power, an average drive power output by the internal combustion engine to the coolant pump is preferably set. This can be done for example by means of an interval operation. For this purpose, for example, the freewheel is activated in both directions at periodic intervals and so shut down the coolant pump cyclically.

In another variant, it is provided that a volume flow of the coolant circuit is controlled by means of the electric motor. For this purpose, the speed of the electric motor is controlled, for example, based on in particular a signal of a motor control. Furthermore, similar to the procedure described above, an interval operation of the electric motor can take place and thus a mean volume flow of the coolant circuit can be set.

According to a development of the electric motor is switched on in a start / stop operation with stationary internal combustion engine. Preferably, in traffic light stop phases or the like of the motor vehicle, a continuous cooling of the drive unit is made possible. In this case, in particular, a cooling of the electric drive unit and optionally at least one auxiliary unit. Furthermore, when the vehicle is stopped, the coolant pump can be provided with a run-on. In addition, the function of a heater can be provided over it. For example, an interior heating, a component heating or the like can thereby be ensured.

When the internal combustion engine is stationary, power electronics are preferably cooled. In particular, a failure derselbigen is prevented or at least reduced by a sufficient and continuous cooling of the power electronics.

Finally, it is provided in a further embodiment that heat absorbed by a cooling of the drive unit is at least partially supplied to a vehicle cabin heating system. Preferably, a coolant flow is controlled as needed in relation to the demand of the internal combustion engine and in relation to the needs of the cabin heater. In the following the invention will be explained in detail with reference to the drawing. However, the features are not limited to the individual embodiments. Rather, features included in the description, including the description of the figures and / or the drawings, can be combined with one another to form further developments.

Show it:

1 shows a drive arrangement of a coolant pump,

Fig. 2 is a hybrid drive unit with a coolant circuit and

Fig. 3 is a first traction sheave and

Fig. 1 shows a drive arrangement of a coolant pump. The coolant pump is a water pump 1, which is fastened by means of a fastening device, not shown, to a drive unit, also not shown. This drive unit may be, for example, a single internal combustion engine or a hybrid drive unit, which includes, for example, an internal combustion engine. In the following the invention is always shown without limiting the generality the example of a hybrid drive unit. The water pump 1 has a first drive shaft 2, on which a pulley 3 is mounted. In this case, an inner bearing shell 4 of the pulley 3 is rotatably connected to the first drive shaft 2. Between the inner bearing shell 4 and an outer ring 5 of the pulley is a freewheel 6 with a bearing. Also fastened to the first drive shaft 2 is an electric motor 7. This has a torque support 8 for a block of engines 9 of an internal combustion engine of the hybrid drive unit shown in the beginning. The freewheel 6 is designed such that a rotational speed of the first drive shaft 2 in a first rotational direction 10, which is a drive rotational direction, can exceed a rotational speed of the outer rim 5 of the belt pulley 3 in the first rotational direction 10. The freewheel 6 is a pawl freewheel. The pulley 3 is driven by means of a drive belt, not shown, which is connected to a likewise not shown output of an internal combustion engine.

Hereinafter, equivalent elements are given the same reference numerals and designations. The hybrid drive unit 1 1 includes an internal combustion engine 12 and an electric drive unit 13. The hybrid drive unit 11 is provided with a coolant circuit 14, the first branch 15 to the internal combustion engine 12, a second branch 16 to the electric drive unit 13, a third branch 17 to a heat exchanger designed as a radiator 18 and a fourth branch 19 to a cabin heater 20. The internal combustion engine 12 is equipped with a second drive shaft 21 on which a drive wheel 22 is mounted. This drive wheel is in engagement with a belt pulley 3 with a drive belt, not shown. The pulley 3 is fastened in a rotationally fixed manner to an inner bearing shell 4 on a first drive shaft 2 of a water pump 1 with the inner bearing shell 4. Between the outer ring 5 of the pulley 3 and the inner bearing shell 4 is a freewheel 6 with a bearing. Also mounted on the first drive shaft 2 is an electric motor 7. This has a torque support 8, which is attached to the hybrid drive unit 11. The freewheel 6 is a sprag freewheel.

The freewheel 6 is designed such that in a first position, a speed of the first drive shaft in a drive direction of the water pump 1 can exceed a speed of the outer rim 5 of the pulley 3. This can be done by means of the electric motor 7, for example, when the internal combustion engine 12, a drive of the water pump 1. In a second position, the freewheel 6 is switched so that no torque transmission between the outer ring 5 of the pulley 3 and the inner bearing shell 4 and thus the first drive shaft 2 is possible. In this position, for example, despite running internal combustion engine 12, the water pump 1 can be deactivated. As a result, for example, as a result of deactivation of the coolant circuit causes heating of the hybrid drive unit.

According to a signal of a motor control, not shown, a circuit of the freewheel 6 and an activation or deactivation of the water pump 1 take place. A circuit of the freewheel is, not shown here, electromagnetically.

For a more flexible dimensioning of corresponding cooling water flows 14 different valves are arranged in the coolant circuit. Thus, a first valve 23 in the first branch 15 to the internal combustion engine 12 is arranged. Furthermore, a second valve 24 is arranged in the second branch to the heat exchanger 18. Finally, a third valve 25 in the third branch 19 to the cabin heater 20 is arranged. Based on not shown thermoswitch or a corresponding control by means also not shown engine control can be effected opening or closing of the corresponding valves. In this case, a partial opening or closing can also be provided. Depending on requirements, for example, the hybrid drive unit 12 mainly the cabin heater or, for example, mainly the heat exchanger 18 to be performed. Furthermore, branches can also be deactivated. This is used, for example, to allow a faster warming of the hybrid drive unit in a cold start phase.

By driving the water pump 1 with the aid of the electric motor 7, a flow of the coolant can be set at least largely independent of a rotational speed of the internal combustion engine. In a variant, not shown, instead of a sprag freewheel also a clutch, in particular with an adjustable slip, can be used. For example, a so-called viscous coupling can be used.

Fig. 3 shows a schematic cross section of a first traction sheave 26. On a first drive shaft 2, a pawl assembly 27 is rotatably attached. A pawl 28 engages in a provided with a Sägezahnverzahnung 29 driver ring 30 a. This driver ring 30 is rotatably mounted in a bearing, not shown, on the first drive shaft 2. Furthermore, the driving ring 30 is fixed to an outer

Driving ring 31 connected. This outer drive ring 31 is used for example for driving by means of a V-belt, not shown. Contrary to the embodiment shown, however, a gear-shaped driving ring can also be used. The pawl 28 is activated with a spring element 32. With an actuation device, not shown, the pawl 28 can be deactivated electromagnetically.

Claims

claims 1. Drive unit (11) of a motor vehicle with at least one internal combustion engine (12) for propulsion of the motor vehicle and a cooling device, the at least one coolant circuit (14), in which at least one coolant pump (1) is arranged, wherein the coolant pump (1 ) has a coupling with the internal combustion engine (12) and at least one electric motor (7) and a freewheel (6) is provided for the coupling. 2. Drive unit (11) according to claim 1, characterized in that the drive unit is a hybrid drive unit, which comprises at least one electric drive unit (13) for propulsion of the motor vehicle. 3. Drive unit (11) according to claim 1 or 2, characterized in that the coupling comprises a first drive connection with the internal combustion engine (12) and a second drive connection to the electric motor (7), wherein by means of the freewheel (6) at least one transmission of a against a driving direction of rotation of the coolant pump (1) acting torque can be interrupted by the first drive connection. 4. Drive unit (11) according to one of claims 1 to 3, characterized in that the freewheel (6) is mechanically switchable. 5. Drive unit (11) according to one of claims 1 to 3, characterized in that the freewheel (6) is electrically switchable. 6. Drive unit (11) according to any one of the preceding claims, characterized in that the freewheel (6) is free-running switchable both in and against the driving direction of rotation. 7. Drive unit (11) according to one of the preceding claims, characterized in that the freewheel (6) is a pawl freewheel. 8. Drive unit (11) according to one of the preceding claims, characterized in that the freewheel (6) is a sprag freewheel. 9. Drive unit (11) according to any one of the preceding claims, characterized in that the freewheel (6) comprises a clutch with adjustable slip. 10. Drive unit (11) according to claim 3, characterized in that the first drive connection is a mechanical connection. 11. Drive unit (11) according to claim 3, characterized in that the first drive connection is selected from the group comprising chain drive, belt drive and / or gear wheel drive. 12. Drive unit (11) according to claim 3, characterized in that the first drive connection comprises a drive disk (3). 13. Drive unit (11) according to claim 12, characterized in that the freewheel (6) in the drive plate (3) is integrated. 14. Drive unit (1 1) according to one of the preceding claims, characterized in that the electric motor (7) on a drive shaft of the coolant pump (1) is arranged and at least one torque support (8). 15. Drive unit (11) according to claim 14, characterized in that the electric motor (7) in the drive plate (3) is integrated. 16. Drive unit (11) according to one of the preceding claims, characterized in that the coolant circuit (14) comprises at least one additionally switchable valve (23; 24; 25). 17. Drive unit (11) according to one of the preceding claims, characterized in that the coolant circuit (14) comprises at least one switchable branch (15; 16; 17) to a cabin heater (20). 18. Drive unit (11) according to one of the preceding claims, characterized in that the coolant circuit (14) comprises exactly one coolant pump (1). 19. A cooling method of a drive unit (11), which comprises at least one internal combustion engine (12), wherein a coolant for cooling the Antriebsag- gregates (11) in at least one coolant circuit (14) of the drive unit (11) by means of at least one coolant pump (1) is circulated, which via a first drive connection via a freewheel (6) of the internal combustion engine (12) is driven, wherein the freewheel (6) is used when the coolant pump (1) in addition to or instead by means of at least one electric motor (7) is driven or not driven. 20. A cooling method according to claim 19, characterized in that the drive unit (11) is a hybrid drive unit comprising at least one electric drive unit (13), wherein a coolant for cooling the internal combustion engine (12) and / or the electric drive unit (13) in at least one coolant circuit (14) of the drive unit (11) is circulated by means of at least one coolant pump (1) which is driven via a first drive connection via a freewheel (6) of the internal combustion engine (12), wherein the freewheel (6) is used, if the coolant pump (1) is additionally or instead driven by means of at least one electric motor (7) or is not driven at all. 21. Cooling method according to claim 19 or 20, characterized in that the coolant pump (1) during operation of the internal combustion engine (12) by means of a circuit of the freewheel (6) is deactivated. 22. Cooling method according to one of claims 19 to 21, characterized in that at least one valve (23; 24; 25) is at least partially opened or closed in the coolant circuit (14) as a function of a rotational speed of the internal combustion engine (12) and / or a temperature , 23. Cooling method according to one of claims 19 to 22, characterized in that one of the internal combustion engine (12) to the coolant pump (1) output drive power is controlled. 24. Cooling method according to one of claims 19 to 23, characterized in that by means of the electric motor (7), a volume flow of the coolant circuit (14) is controlled. 25. Cooling method according to one of claims 19 to 24, characterized in that the electric motor in a start / stop operation with stationary Verbrennungskraftmaschi- ne (12) is switched on. 26. Cooling method according to one of claims 19 to 25, characterized in that a power electronics is cooled with stationary internal combustion engine (12) with at least a portion of the circulated coolant. 27. Cooling method according to one of claims 19 to 26, characterized in that at a cooling of the drive unit (11) absorbed heat at least partially a vehicle cabin heater (20) is supplied.