DE102007061417A1 - Hybrid drive e.g. parallel hybrid drive, for use in e.g. commercial vehicle, has air compressor attached to electric motor for generating air for compressed plant, and another motor formed as compressor drive attached to air compressor - Google Patents

Abstract

The drive (10) has an internal combustion engine (12), and an electric motor (14) for driving a motor vehicle. An air compressor (36) attached to the electric motor generates compressed air for a compressed plant. Another electric motor formed as a compressor drive is attached to the air compressor. The latter electric motor and the air compressor form a structural unit and arranged in housing. The compressed plant has a control device (46) for controlling the air compressor. The control device forms a part of an engine control (54) or connected with the engine control. An independent claim is also included for a method for operating an air compressor of a hybrid drive.

Description

The The invention relates to a hybrid drive for a motor vehicle, the internal combustion engine and has a first electric motor for driving the motor vehicle, and associated with a compressed air compressor for generating compressed air for a compressed air system is.

The The invention further relates to a method for operating an air compressor a corresponding hybrid drive and a motor vehicle with a Hybrid drive.

hybrid drives include two drive motors, over a hybrid vehicle can be driven, namely a Internal combustion engine and an electric motor. While the internal combustion engine with liquid or gaseous Fuel is supplied to the drive by the electric motor using stored electrical energy, for example from a vehicle battery, or from a fuel cell. The Engines can depending on the current driving situation alternately or simultaneously operate. For example, in one version you have one Load distribution gear for the suitable transmission of the driving force generated by them to a main output, coupled to the drive wheels of the motor vehicle are, downstream. Is the vehicle in a push phase, especially when going downhill, so can via the drive train backwards energy transferred to the electric motor this being then as a generator to charge the battery is working.

numerous Vehicles, in particular commercial vehicles, have an air compressor. With this compressed air is generated, which is a compressed air system with compressed air consumers of the vehicle available can be provided, in particular a pneumatic brake system, but also, for example, an air suspension or Liftachseinrichtung. Therefore the generation of compressed air energy is needed, one endeavors to choose the operating phases of the air compressor as economically as possible, so that on the one hand no unnecessary Compressed air generation takes place, but on the other hand ensured is that at any time a sufficient supply of compressed air for disposal stands, even if compressed air consuming driving situations available. Particularly anxious in this context, shear phases exploit the motor vehicle to the converted into kinetic energy potential energy, for example when going downhill, too to use for the production of compressed air. In a push phase is the internal combustion engine or the electric motor of the rolling vehicle driven. Shear phases can For example, be determined by the injection and Load behavior of the internal combustion engine or the load behavior of the Electric motor, for example, based on the current direction and current at an asynchronous machine, monitored become.

Of the Invention is based on the object, a hybrid drive for motor vehicles and a method of operating an air compressor of such Hybrid drive available to put, with a more efficient use of overrun phases of the vehicle guaranteed becomes.

These The object is achieved by the features of the independent claims.

One inventive hybrid drive for a motor vehicle, an internal combustion engine and a first electric motor for driving of the motor vehicle, and a compressed air compressor for Generation of compressed air for a compressed air system is assigned, is characterized that the air compressor, a second electric motor as a compressor drive assigned. As a result, it is advantageously possible for the compressed air compressor to be independent of the speed and the operating state of the first electric motor and of the internal combustion engine can be operated.

An inventive method for operating an air compressor of such a hybrid drive comprises the following method steps:
Monitoring operating parameters and a compressed air system of the motor vehicle for determining a coasting phase of the motor vehicle, in which the internal combustion engine and / or the first electric motor is driven by a driving movement of the motor vehicle, and a supply pressure requirement of a compressed air system of the motor vehicle;
Generating electrical energy with the first electric motor when a coasting phase of the motor vehicle is present; and
Operating the air compressor by supplying the second electric motor with the electrical energy generated by the first electric motor when a coasting phase of the motor vehicle and a supply pressure requirement is present.

Thereby is advantageously achieved that in deceleration phases of the motor vehicle its potential energy through the powered first electric motor converted into electrical energy to drive the air compressor can be. The first electric motor generates in coasting phases, for example at a charged vehicle battery continues to have electrical energy, which is no longer stored in the battery and thus for compressed air generation to disposal stands.

advantageous embodiments of the invention are in the dependent claims specified.

Of the Hybrid drive can be designed in various designs, so for example as a so-called parallel hybrid drive, partial hybrid drive or full hybrid drive. In all versions, the second electric motor of compressed air compressor with electrical energy from a store, to Example of a vehicle battery, and / or generated by the first Electric motor drivable. Thus, a broad field of application is the Invention created.

It is in an execution provided that the second electric motor with the air compressor forms a structural unit, it being preferred that these two units arranged in a housing are, whereby a space savings with additional functionality is possible.

A alternative design provides that the air compressor via a main output of a drivable downstream of the hybrid drive load distribution gear is. For this purpose, the compressed air compressor via a controllable coupling device connected to the main output. By this arrangement of the air compressor in the drive system it is ensured that the compressed air compressor from both the engine and the first electric motor can be driven. Furthermore, at the same time in overrun mode first electric motor and the compressor via their coupling to the main drive are driven. this makes possible on the one hand, the generation of electrical energy for charging a battery and on the other hand the generation of compressed air during the coasting phases of the vehicle.

It can be provided that the main output in the load distribution gearbox is integrated. The load distribution gear can thus from the outset be designed in such a way that the connection according to the invention the engines and the compressor to the load distribution gearbox can. It is also possible, a mechanical coupling between the clutch and the load distribution gearbox via a outside the main load distribution gear lying main output unit available too put.

Of the by the second electric motor electrically driven air compressor is thus advantageously in a simple manner via an electrical switch between a funding phase and a non-promotion phase switchable.

Also can be provided that the air compressor a pneumatic Having switching input and by venting the pneumatic switching input from a funding phase in a characterized by idle of the air compressor Non-promotion phase is transferable. Also by the transfer of the Compressed air compressor in an idle phase can save energy be, namely then when no compressed air is needed becomes.

In In this context, it may be useful that the controllable coupling device is an electrically controllable Switching valve comprising an electronic control unit a compressed air supply device can be controlled. The coupling device can be either completely electric be controllable, such as an electromagnetic clutch, or Completely be pneumatically controllable, for example as a pneumatically actuated clutch. An electropneumatic control is possible, with the switching valve either is electrically or pneumatically controllable and either one electric current for actuation an electromagnetic clutch or a compressed air flow for actuating a Compressed air coupling switches.

It is in another embodiment provided that the compressed air compressor on its pressure side over a Compressed air supply device connected to a compressed air reservoir is, wherein the compressed air supply device is a check valve having in a connection to at least one compressed air reservoir. It may also have an air dryer unit which is used for regeneration by bypassing the check valve the at least one compressed air reservoir removable compressed air actuated is.

A compressed air supply device is a component to be provided in each commercial vehicle having a pneumatically operated brake system. The compressed air supply device ensures the cleaning and drying of the compressed air. By the compressed air supply device pressure regulator functions and a multi-circuit protection valve to ensure a filling order of compressed air storage reservoirs and to protect individual consumer circuits against each other are still frequently provided. Such a compressed air supply device often has its own electronic control unit, or it is controlled by electrical signals of a control unit, which also performs other control functions in the vehicle, for example, from a vehicle computer. In any case, it may be useful to control the air compressor by means of signals supplied by the electronics controlling the compressed air supply device, since here the primary information converges with regard to the operating state of the compressed air supply, for example pressures detected in the service brake circuits, Temperatures etc.

In another embodiment is provided that a start of the air compressor for generating of compressed air based on definable characteristic values. The switching on of the air compressor is not abrupt, but in a kind of a soft start according to a characteristic as a function a start-up time. This is particularly gentle in the case of use of dry running compressors this by avoiding start-up shocks and the power supply by eliminating start-up current peaks. In the area In operation, such a compressor will then be at a constant Speed through the second electric motor in the best efficiency map operated the complete unit, with an overall efficiency that Product of the efficiency of the compressor and the efficiency of the second electric motor.

Farther it is advantageous that the air compressor in the overrun phase of the motor vehicle can be used as an engine brake, wherein his compression work can be exploited as a braking effect.

The The invention further relates to a motor vehicle with a hybrid drive according to the invention.

The Invention will now be described with reference to the accompanying drawings particularly preferred embodiments exemplified.

It demonstrate:

1 a schematic representation of a first embodiment of a hybrid drive according to the invention and related vehicle components;

2 a schematic representation of a second embodiment of the hybrid drive according to the invention and related vehicle components; and

3 a flowchart for explaining a method according to the invention.

1 shows a schematic representation of a first embodiment of a hybrid drive according to the invention 10 as well as related vehicle components of a motor vehicle, not shown, for example, a commercial vehicle. In this illustration, the functional components are interconnected by solid lines, broken lines and double lines. Here, solid lines indicate compressed air connections, broken lines electrical connections and double-line components, such as shafts, for transmitting mechanical force.

The hybrid drive 10 includes an internal combustion engine 12 and a first electric motor 14 , The motors 12 . 14 stand with an engine control unit 54 electrically connected. The engine control unit 54 still stands with a battery 52 in connection. Mechanical are the engines 12 . 14 with a load distribution gearbox 16 coupled, the main output 18 is downstream. The load distribution gearbox 16 This is also done by the engine control in this example 54 controlled. The main output 18 provides the connection of the load distribution gearbox 16 with a differential gear 20 available through which a drive torque on drive wheels 22 . 24 , For example, the rear axle, the motor vehicle is transmitted. The drive wheels 22 . 24 stand with brake actuators 26 . 28 in relation, in the present example of a brake pressure control device 30 be controlled with compressed air. At the main output 18 is still a clutch input shaft 32 coupled to the input side of a coupling device 34 leads. On the output side is the coupling device 34 with a compressed air compressor 36 coupled. The air compressor 36 is via a compressed air supply device 38 , which here has an air dryer, a pressure regulator and a multi-circuit protection valve, with a compressed air reservoir 40 in connection. About this compressed air reservoir 40 becomes the aforementioned brake pressure control 30 supplied with compressed air. The air compressor 36 can by disconnecting the coupling device 34 be transferred to a non-funding phase, for which purpose a control input of the coupling device 34 Compressed air is supplied. The control of the coupling device 34 via an electrically controllable valve 44 , which is preferably designed as a 3/2-way valve, so as to a venting and a ventilating state for a pneumatic control input of the coupling device 34 to provide. The valve 44 is from an electronic control unit 46 controlled, which is also the control of the compressed air supply device 38 serves. The control unit 46 can in the compressed air supply device 38 be integrated. The control 46 is also in communication with a CAN bus of the vehicle which connects various signal generators and signal receivers of the vehicle. For example, the engine control is also 54 with the CAN bus 48 coupled. The electronic control unit 46 for controlling the valve 44 and the compressed air supply device 38 also receives an output signal from a pressure sensor 50 , which determines the operating pressure in the compressed air reservoir 40 detected. In addition to the illustrated embodiment, it is possible that the control of all functions of the engine control unit 16 is perceived. Furthermore, it can also be provided that a part of the Functions that represent the electronic control unit 46 takes over from the engine control unit 16 is taken over. A communication from engine control unit 16 and control unit 46 over the CAN bus 48 is of course possible.

During operation of the vehicle this is either from the internal combustion engine 12 , from the first electric motor 14 or driven by both. The first electric motor 14 For this purpose draws its energy from the battery 52 or for example from a fuel cell, not shown. Which engine 12 . 14 is active and how the generated driving force is transmitted to the drive train is from the engine control 54 determined and by the load distribution gear 16 taught. When compressed air is required, the compressed air compressor compresses 36 Air and pump them into the compressed air reservoir 40 by giving drive power over the main output 18 and the case engaged clutch device 34 refers, in the normal operation of the motor vehicle of the internal combustion engine 12 and / or the first electric motor 14 is delivered. Also, driving force is applied to the drive wheels 22 . 24 transfer. If the motor vehicle enters a coasting mode or a coasting phase, the power transmission in the drive train reverses, that is, the force is transmitted by the drive wheels 22 . 24 over the differential gear 20 , the main shoot 18 and the load distribution gearbox 16 on the engines 12 . 14 transfer. With a suitable design of the first electric motor 14 and the engine control 54 may be the first electric motor 14 work as a generator, leaving the battery 52 can be charged. At the same time, in the coasting phase of the vehicle, the compressed air compressor 36 be powered without requiring fuel or electrical energy from the battery 52 would be needed.

In the embodiment shown here is the air compressor 36 a second electric motor 37 associated with which with the air compressor 36 is in drive connection. This second electric motor 37 is in a coasting phase of the vehicle by the case as a generator operated first electric motor 14 supplied with electrical energy, in which case the coupling device 34 is disengaged and a drive connection of the air compressor 36 from the main output 18 separates.

This is particularly advantageous if, for example, in the overrun phase, the speed of the main output 18 is too low to a sufficient Druckluftförde tion of the air compressor 36 to ensure. In such a case, the speed of the first electric motor 14 be too low. Then the air compressor can 36 nevertheless at a compressed air demand by the second electric motor 37 be operated by this from the vehicle battery 52 or a fuel cell is supplied with electrical energy.

To detect this useful boost phase, the motor vehicle is constantly monitored for the presence of such a coasting phase, for example by means of the engine control 54 , If it is determined that there is a coasting phase, the generator operation of the electric motor will in any case be used 14 occurred. Is in addition the system pressure of the compressed air reservoir 40 below a maximum pressure, so the air compressor 36 be transferred to the funding phase. For example, it can be provided that whenever the engine control unit 16 switched to generator mode, a signal to the valve 44 to disconnect the clutch 34 is issued. The signal can be the valve 44 directly from the engine control 54 be transmitted or, as in connection with the illustrated embodiment, indirectly via the CAN bus 48 and the electronic control unit 46 the compressed air supply device 38 to provide.

2 shows a schematic representation of a second embodiment of a hybrid drive according to the invention and related vehicle components. In contrast to 1 are in the embodiment according to 2 no second electric motor 37 and no coupling means between the air compressor 36 and the main output 18 provided, wherein the compressed air compressor 36 here constantly with the main output 18 connected is. Instead, the air compressor has 36 a pneumatic control input 42 , Will this pneumatic control input 42 through the valve 44 vented, so the air compressor switches 36 in idle mode. The embodiment according to 2 works insofar control technology identical to the embodiment according to 1 , so that reference is made to the above statements.

A second electric motor 37 may still be possible, for example, in an alternative embodiment - not shown - the coupling device 34 inside the air compressor 36 is arranged and, for example, pneumatically with the pneumatic control input 42 is operable.

3 shows a flowchart for explaining a method according to the invention for operating an air compressor 36 the hybrid drive according to the invention 10 , According to a step S001, operating parameters are permanently monitored, for example the driving state of the vehicle with regard to the overrun phase or the overrun operation. If it is determined in a step S002 that overrun operation is present, then, in a step S003, a transition is made to electrical energy the first electric motor 14 to create. As long as a non-present overrun operation is determined in step S002, the operating parameters are continuously monitored in step S001. Following step S003, that is during the generation of electrical energy via the first electric motor 14 , it is determined in a step S004 whether a maximum supply pressure is reached or a supply pressure requirement exists. If this is the case, then according to a step S005 the compressed air compressor 36 will be transferred to a non-promotion phase or will be maintained. Following step S005, it is further queried in step S002 whether the coasting operation is present. If it is determined in step S004 that a maximum supply pressure has not been reached, then the compressed air compressor 36 according to a step S006 in a conveying phase, by the second electric motor 37 with electrical energy (from the first electric motor 14 or from the battery 52 ), or such is maintained. Following this, it is again checked in accordance with step S007 whether the overrun operation is still present. If this is the case, then in step S003 with the generation of electrical energy by means of the first electric motor 14 continued. If it is determined in step S007 that there is no overrun operation, then the air compressor 36 in step S005 into its non-production phase. Subsequently, in step S002, it is again checked whether coasting is present. Since this will not usually be the case, the method continues to monitor the operating parameters according to step S001. Otherwise, it may revert to the generation of electrical energy via the first electric motor 14 in step S003 and possibly in the generation of compressed air utilizing the overrun operation.

The case in which in overrun operation too low a drive speed for the air compressor 36 is not shown, but easy to imagine. Here, for example, in step S002 and S007, the rotational speed of the main output becomes 18 compared with a definable threshold and in step S003 electrical energy from the battery 52 or for example from a fuel cell provided, with which the second electric motor 37 is operated at a determined compressed air demand.

A signal for the coupling device 34 to enter or exit is generated in steps S006 and S005.

In the event that the first electric motor 14 no electrical energy for operating the second electric motor 37 This is generated by the battery 52 fed, as described above. Or the coupling device 34 can be engaged to the air compressor 36 to connect directly to the main output at sufficient drive speed in overrun mode. Thus, several backup options to ensure a compressed air supply through the air compressor 36 created.

In a non-illustrated but easily imaginable third embodiment of the second electric motor 37 provided compressed air compressor 36 not with the load distribution gearbox 16 or mechanically coupled to a drive train of the motor vehicle. In this case, the air compressor 36 only from the second electric motor 37 driven. This is also a decentralized arrangement of the air compressor 36 possible, because only electrical connections in the form of electrical power supply from the battery 52 and / or the first electric motor 14 and electrical control lines, for example, from the engine controller 54 to the control unit 46 necessary.

The hybrid drive shown in the figures 10 is shown as an example only as a so-called parallel hybrid drive. Of course, the hybrid drive 10 also be designed as a partial or full hybrid drive.

The in the above description, in the drawings and in the claims disclosed features of the invention can both individually and also in any combination for the realization of the invention be essential.

The Invention is not limited to the described embodiments.

So it is also possible, for example, that in a coasting phase without compressed air demand of the air compressor 36 via the coupling device 34 with the main output 18 can be connected to form an (additional) engine braking function. In this case, the air compressor 36 be set in an operating state in which it does not compress air, but only performs compression work and thus produces a braking effect.

Furthermore, it is also conceivable that the second electric motor 37 can be used as an additional or emergency generator by the compressed air compressor 36 that with the second electric motor 37 is coupled, via the engaged clutch device 34 with the main output 18 is coupled. This can be possible at any time, thus providing an emergency power supply.

10

hybrid drive

12

internal combustion engine

14

first electric motor

16

Load balancing gear

18

main output

20

differential gear

22

drive wheel

24

drive wheel

26

brake actuator

28

brake actuator

30

Brake pressure control

32

Clutch input shaft

34

coupling device

36

Air Compressor

37

second electric motor

38

Compressed air supply system

40

Compressed air reservoir

42

control input

44

Valve

46

control unit

48

CAN bus

50

pressure sensor

52

battery

54

motor control

Claims (18)

Hybrid drive ( 10 ) for a motor vehicle having an internal combustion engine ( 12 ) and a first electric motor ( 14 ) for driving the motor vehicle, and a compressed air compressor ( 36 ) is assigned to the production of compressed air for a compressed air system, characterized in that the compressed air compressor ( 36 ) A second electric motor is assigned as a compressor drive. Hybrid drive ( 10 ) according to claim 1, characterized in that the hybrid drive ( 10 ) is designed as a parallel hybrid drive, partial hybrid drive or full hybrid drive. Hybrid drive ( 10 ) according to claim 1 or 2, characterized in that the second electric motor and the compressed air compressor ( 36 ) form a structural unit. Hybrid drive ( 10 ) according to claim 3, characterized in that the second electric motor and the compressed air compressor ( 36 ) are arranged in a housing. Hybrid drive ( 10 ) according to one of the preceding claims, characterized in that the compressed air system has a control unit ( 46 ) for controlling the pneumatic compressor ( 36 ), which is part of a motor control ( 54 ) or is connected to this. Hybrid drive ( 10 ) according to one of the preceding claims, characterized in that the compressed air compressor ( 36 ) on its pressure side via a compressed air supply device ( 38 ) with a compressed air reservoir ( 40 ), wherein the compressed air supply device ( 38 ) a check valve in a connection to at least one compressed air reservoir ( 40 ) having. Hybrid drive ( 10 ) according to claim 6, characterized in that the compressed air supply device ( 38 ) has an air dryer unit, which for regeneration by bypassing the check valve from the at least one compressed air reservoir ( 40 ) Removable compressed air is actuated. Hybrid drive ( 10 ) according to one of the preceding claims, characterized in that the compressed air compressor ( 36 ) via a controllable coupling device ( 34 ) with a main output ( 18 ) of the hybrid drive ( 10 ) downstream load distribution gear ( 16 ) is coupled. Hybrid drive ( 10 ) according to claim 8, characterized in that the controllable coupling device ( 34 ) is electrically or pneumatically controllable. Hybrid drive ( 10 ) according to claim 8 or 9, characterized in that the main output ( 18 ) as a component of the load distribution gearbox ( 16 ) is trained. Hybrid drive ( 10 ) according to one of claims 8 to 10, characterized in that the coupling device ( 34 ) as a component of the air compressor ( 36 ) is trained. Method for operating an air compressor ( 36 ) of a hybrid drive ( 10 ) according to one of claims 1 to 7, characterized in that the method comprises the following method steps: (a) monitoring of operating parameters and a compressed air system of the motor vehicle for determining a coasting phase of the motor vehicle, in which the internal combustion engine ( 12 ) and / or the first electric motor ( 14 ) is driven by a driving movement of the motor vehicle /, and a supply pressure requirement of a compressed air system of the motor vehicle; (b) generating electrical energy with the first electric motor ( 14 ), when a coasting phase of the motor vehicle is present; and (c) operating the air compressor ( 36 ) by supplying the second electric motor ( 37 ) with that of the first electric motor ( 14 ) generated electric energy when a coasting phase of the motor vehicle and a supply pressure requirement is present. A method according to claim 12, characterized in that at a supply pressure requirement and falls below a predetermined value for the speed of the main output ( 18 ) the compressed air compressor ( 36 ) of the second electric motor ( 37 ), wherein the second electric motor ( 37 ) is supplied by a battery and / or fuel cell of the motor vehicle. Method for operating an air compressor ( 36 ) of a hybrid drive ( 10 ) according to one of claims 8 to 11, characterized in that the method comprises the following method steps: (a) monitoring of operating parameters and a compressed air system of the motor vehicle for determining a coasting phase of the motor vehicle, in which the internal combustion engine ( 12 ) and / or the electric motor ( 14 ) is driven by a driving movement of the motor vehicle /, and a supply pressure requirement of a compressed air system of the motor vehicle; (b) generating electrical energy with the first electric motor ( 14 ), when a coasting phase of the motor vehicle is present; and (c) operating the air compressor ( 36 ), when a coasting phase of the motor vehicle and a supply pressure requirement is present, by controlling the coupling device ( 34 ) for a coupling of the compressed air compressor ( 36 ) with the main output ( 18 ), or by supplying the second electric motor ( 37 ) with that of the first electric motor ( 14 ) generated electrical energy and control of the coupling device ( 34 ) for a separation of the compressed air compressor ( 36 ) of the main output ( 18 ). A method according to claim 14, characterized in that at a supply pressure requirement and falls below a predetermined value for the speed of the main output ( 18 ) the compressed air compressor ( 36 ) of the second electric motor ( 37 ), wherein the second electric motor ( 37 ) is supplied by an electrical energy store of the motor vehicle and the coupling device ( 34 ) for a separation of the compressed air compressor ( 36 ) of the main output ( 18 ) is driven. Method according to one of claims 12 to 15, characterized in that a start of the pneumatic compressor ( 36 ) for generating compressed air on the basis of definable characteristic values. Method according to one of claims 12 to 16, characterized in that the compressed air compressor ( 36 ) is used in the overrun phase of the motor vehicle as an engine brake. Motor vehicle with a hybrid drive ( 10 ) according to one of claims 1 to 11.