DE102008021976B4 - Motor vehicle with an auxiliary unit driven by an electric motor - Google Patents

Abstract

Motor vehicle and in particular commercial vehicle with an internal combustion engine (2) for driving the motor vehicle, with at least one auxiliary unit (10) and with one (4) which can be supplied with electrical energy at least temporarily from a power source (8), the electric motor (4) at least is temporarily connected to the auxiliary unit (10) via a power transmission device (28) in order to drive it, the motor vehicle has a first coupling device (16) by means of which an output shaft (3) of the internal combustion engine (2) rotates with a drive shaft (5) of the electric motor (4) can be connected and which enables a temporary mechanical drive of the electric motor (4) by the internal combustion engine (2), the motor vehicle has a second clutch device (18) which drives the auxiliary unit (10) by the internal combustion engine (2) enables an air conditioning system in overrun or braking operation directly via the second clutch device (18) and g If necessary, it is also connected to the internal combustion engine (2) via belt or gear wheels in order to use the energy fed back for air conditioning the motor vehicle, and the electric motor (4) is designed in such a way that the internal combustion engine (2) is powered by the electric motor (4). an additional torque can be applied to support, and / or the electric motor (4) and the internal combustion engine (2) are designed in such a way that the electric motor (4) supports or substitutes the internal combustion engine (2) in a partial load range of the internal combustion engine (2).

Description

The present invention relates to a motor vehicle. The invention is described with reference to a utility vehicle, in particular a truck or bus, but it is pointed out that the present invention can also be used for cars.

Motor vehicles known from the prior art usually have a large number of vehicle ancillary units. All auxiliary machines of a vehicle that are driven directly or indirectly by the main drive machine and that are necessary for the operation of the main machine or the vehicle are referred to as auxiliary units. In addition, auxiliary units also refer to those units that are not directly necessary for driving, but support them in some other way, for example in driving comfort, such as, in particular, but not exclusively, the air conditioning compressor for a vehicle air conditioning system.

In the known vehicles, it is desirable to provide an air-conditioned bus vehicle at the start of operation, during longer vehicle downtimes or at the terminal stops, for example for waiting passengers. The operation of an air conditioning system, however, especially in a city bus, is only possible in connection with a running internal combustion engine in order to ensure the necessary drive energy for the air conditioning compressor. The air conditioning compressor is usually driven directly by the internal combustion engine. However, with longer stopping times, this leads to noise and exhaust emissions from the internal combustion engine in the vicinity of the stop. This environmental pollution is particularly evident in the hot seasons, as a large number of coaches transport day tourists. In such cases, a bus often serves as a place to stay and, in addition to air conditioning the passenger compartment, also has to implement other comfort functions such as kitchen operation, entertainment electronics, showers, etc.

In order to enable the 24 volt on-board power supply at the terminal stops even when the air conditioning system is in operation, and at the same time to avoid deep discharge of the 24 volt batteries, electrical energy is generated with low efficiency via the alternator from the internal combustion engine. When starting, for example from a bus stop, the drive reduces z. B. for the air conditioning compressor in addition to other ancillary units currently in operation, the power available for starting up.

Satisfactory operation of an air conditioning system and an adequate supply of the electrical system are not possible today when the internal combustion engine is switched off. Furthermore, the drive of the fan for the engine cooling system and also other ancillary units is rigidly connected to the engine speed. The fan can either be adjusted to the engine speed either via a clutch or, in the case of hydraulic drive systems, with a valve, or it can be moved at a lower speed. However, this mode of operation is not always appropriate to the cooling requirement and generally to the ancillary equipment system.

Motor vehicles with internal combustion engines, electric motors and auxiliary units are, for example, from the DE 698 31 049 T2 , DE 197 27 058 A1 , DE 197 38 250 A1 and the 10 2004 043 589 A1 known.

The present invention is therefore based on the object of making available a vehicle which enables the auxiliary unit to be operated, for example even when the internal combustion engine is switched off, for longer downtimes at bus stops. In addition, the fuel's energy should also be used efficiently while driving. Finally, the needs-based operation of additional vehicle ancillary units such as the fan of the engine cooling system should also enable fuel savings. In this way, a possibility should be created to operate the internal combustion engine itself in an energy-optimized and efficient manner.

According to the invention, these objects are achieved by the subject matter of claim 1. Advantageous embodiments and developments are the subject of the subclaims.

A motor vehicle according to the invention and in particular a commercial vehicle has an internal combustion engine for driving the vehicle. Furthermore, at least one auxiliary unit and at least one electric motor are provided, which can be supplied with electrical energy at least temporarily from a power source. According to the invention, the electric motor is at least temporarily connected to the auxiliary unit via a power transmission device in order to drive it.

Furthermore, the vehicle has a coupling device, by means of which an output shaft of the internal combustion engine can be rotationally connected to a shaft of the electric motor in order to temporarily achieve a mechanical drive of the electric motor by the internal combustion engine. This coupling device can be arranged directly between the output shaft of the internal combustion engine and the drive or output shaft of the electric motor, but it would also be possible that the Power is also transmitted via belts, gears or the like.

It is proposed according to the invention to drive air conditioning compressors or other auxiliary units at least temporarily mechanically via an additional electric motor. In this way, an air conditioning compressor or air conditioning system can be switched on and off as required, and this in particular also in the event of the engine being at a standstill. In this way, a concept for the operation of the auxiliary unit is made available in such a way that the air conditioning system can be operated for longer downtimes at bus stops when the internal combustion engine is switched off and the energy of the fuel can also be used more efficiently while driving. Thus, according to the invention, the auxiliary unit, such as an air conditioning compressor, can be driven by the electric motor and preferably controlled via power electronics as required.

According to the invention, it is proposed that the electric motor be designed in such a way that the electric motor acts on the internal combustion engine with an additional torque to assist. Alternatively or additionally, the electric motor and the internal combustion engine are designed in such a way that the electric motor supports or substitutes the internal combustion engine in a partial load range of the internal combustion engine.

The first clutch device makes it possible for the electric motor to be driven by the internal combustion engine and to act as a generator in this state. In a further advantageous embodiment, the auxiliary unit is formed from a group of auxiliary units which contains air compressors, air conditioning compressors, power steering pumps, fans, lubricant pumps, hydraulic pumps, cooling water pumps, fuel pumps, injection pumps, metering pumps, brake boosters and the like.

According to the invention, the motor vehicle has a second clutch device which enables the auxiliary unit to be driven by the internal combustion engine. It is possible, for example, to connect an air conditioning system to the internal combustion engine directly via this clutch and possibly also via belt or gear wheels in energetically favorable operating cases, such as coasting or braking, in order to feed back energy for air conditioning the vehicle to use. In these operating phases, the electric motor is preferably used as a generator and supplies the on-board network and also other electrical auxiliary units with electrical energy.

In a further advantageous embodiment, the electric motor is designed in such a way that it acts as a generator at least at times. In this way, the starter and alternator are preferably replaced by an electric motor with power electronics and preferably also by an on-board power supply converter.

A plurality of auxiliary units can preferably be driven by the electric motor.

In a further advantageous embodiment, the power source is selected from a group of power sources which contains electrical energy stores, fuel cell systems, steam engines with generators, diesel generator sets, exhaust gas turbines with generators, thermocouples, combinations thereof or the like. Other systems for generating electricity can also be used. At least one of these power sources mentioned is preferably operated independently of the use of the internal combustion engine for the drive.

The use of this power source or auxiliary power source makes sense if the path to power generation and to drive an auxiliary unit is more favorable in terms of energy and emissions than the operation of the internal combustion engine of the traction drive directly in connection with the auxiliary unit or the alternator.

As mentioned above, in order to increase the efficiency of the overall system of the vehicle, auxiliary power source and auxiliary units, the electric motor that drives the auxiliary unit or the air conditioning compressor can also be connected to the shaft of the combustion engine or diesel engine via the coupling mentioned above. During the overrun phases of the vehicle, this clutch can be closed and z. B. the air conditioning compressor so directly use braking energy for its operation of the air conditioning system. This also drives the electric motor, which now works as a generator and optionally supplies the vehicle's 24 volt on-board network via an on-board power supply electronics. The power output of the auxiliary power source can thus be reduced and fuel savings can be achieved.

With an appropriate design of the electric motor, several auxiliary units can be driven simultaneously via clutches and belts or gears. In addition to air conditioning, z. B. the fan of the vehicle cooling system can be operated in the manner described. The drive power of the fan is in a similar power range as that of the air conditioning compressor. The motor vehicle would therefore have to be equipped with greater electrical machine power as soon as several power take-offs are working at the same time.

In a further advantageous embodiment, the internal combustion engine and / or the auxiliary units, such as an electric motor or air conditioning compressor, are designed as a common module or are arranged in a common module. In this way it is possible to retrofit an entire module, for example in motor vehicles.

In a further advantageous embodiment, the electric motor also serves as a starter for the motor vehicle and, in a further embodiment, as an alternator for the motor vehicle.

The present invention is also directed to a supply module for a motor vehicle, this supply module having an electric motor and a first coupling device via which the electric motor can be mechanically connected to and mechanically driven by an output shaft of an internal combustion engine of the motor vehicle. Furthermore, the module has a second coupling device via which the electric motor can be connected to the auxiliary unit of the motor vehicle, the supply module furthermore having a connection in order to supply the electric motor with electrical energy. In this supply module, too, it is provided that an auxiliary unit of the motor vehicle is mechanically driven by the electric motor. The energy supply of the electric motor, for example when the vehicle is at a standstill, is secured again via a further power source, as mentioned above.

The supply module preferably has a plurality of second coupling devices which can be controlled independently of one another.

The present invention is further directed to a method for operating a motor vehicle, the motor vehicle having an internal combustion engine for driving the motor vehicle and at least one auxiliary unit that can be switched on and off. Furthermore, an electric motor is provided which can be supplied with electrical energy at least temporarily from a power source.

• Darin zeigen:
  • 1: ein Blockdiagramm einer Anordnung für ein erfindungsgemäßes Kraftfahrzeug; und
  • 2: eine weitere schematische Darstellung zur Veranschaulichung der Erfindung.

According to the invention, the auxiliary unit is at least temporarily driven mechanically by the electric motor. Furthermore, the auxiliary unit is advantageously also driven mechanically from the internal combustion engine at times. As in the further preferred methods, the electric motor is also driven at least temporarily by the internal combustion engine. In this way it is again achieved that on the one hand the electric motor can be used both as a motor and as a generator and on the other hand that the auxiliary unit can be operated either by the internal combustion engine or the electric motor. Further embodiments and developments emerge from the attached figures:

• Show in it:
  • 1 : a block diagram of an arrangement for a motor vehicle according to the invention; and
  • 2 : Another schematic representation to illustrate the invention.

1 Figure 3 shows a block diagram to illustrate the present invention. A motor vehicle (not shown) has an internal combustion engine 2 on, which has a first coupling device 16 with an electric motor 4th can be connected to drive this. More precisely, there is an output shaft 3rd of the internal combustion engine via the first clutch device 16 and a strap 26th with a drive shaft 5 of the electric motor 4th in connection.

The electric motor 4th drives in turn via a belt 28 and a second coupling device 18th an auxiliary unit, such as an air conditioning compressor and an air compressor 10 at.

With an appropriate design of the electric motor, further ancillary units can be used at the same time 10 be driven via clutches and belts or gears as required. The reference number 20th refers to the supply module in its entirety, consisting of the electric motor 4th and the individual coupling devices 16 , 18th as well as the strap 26th , 28 .

The reference number 30th refers to a control device that is equipped with software adapted for this purpose. With the help of this control device 30th the ancillary units in the in 1 Operate the arrangement shown in a demand and energy-optimized manner. If a certain auxiliary unit is not required, its power output can be reduced or even by switching off the electric motor or by opening one of the clutches 18th all set. Such a control can take place in an automated manner, for example as a function of parameters such as the temperature or the vehicle status, but it would also be possible for the user to act on the device himself.

About the starting performance of the internal combustion engine 2 The clutch, for example, can make it completely available for the journey out of the bus stop 18th on the auxiliary unit 10 be opened and the air conditioning operation will be suspended for the time of start-up. However, it would also be possible that the drive of the Air conditioning compressor 10 by the electric motor 4th takes place, for this purpose electricity from an electrical source 8th is used. In this case, the first coupling device is then preferred 16 towards the internal combustion engine 2 open.

In an overrun or braking operation, it is possible to recover energy. In order to avoid the clutch jolt during the transition to the overrun phase and thus a generator operation of the electric motor, the electric motor can be brought to the speed of the internal combustion engine in motor operation, whereby a corresponding gear ratio has to be taken into account. In the ideal case, the clutch can now be operated at the same speed as the electric motor 4th and the internal combustion engine 2 close smoothly. The power electronics are then controlled by the electric motor in generator mode for generating electrical energy. Preferably, the connected ancillary units can be connected in parallel to this via closed couplings 18th by straps 28 with the internal combustion engine 2 are connected and in this way also use the recovered energy directly.

With an appropriately designed electric motor 4th can have a boost function for the internal combustion engine 2 to increase performance and save fuel. Energy for the electric motor 4th in this case comes from electrical power sources 8th .

In particular, the use of a powerful electric motor can support the internal combustion engine and contribute to overcoming internal friction losses with reduced fuel consumption by using the electric motor 4th the internal combustion engine 2 brings it to the desired fuel-efficient operating point as quickly as possible.

In addition, the power gap at low speeds during start-up, which is generated, for example, by the turbocharging characteristic, can be bridged indirectly in this way.

The electric motor 4th can the internal combustion engine 2 support or even replace during the phases of undisturbed traffic flow and a resulting weak partial load operation, in which case the fuel supply of the internal combustion engine is reduced or switched off. As soon as increased driving performance is required again, the load control switches the combustion engine 2 again or increases its power output.

By installing a suitable electric motor 4th can save fuel through start-stop operation of the internal combustion engine 2 will be realized. When waiting at traffic lights and other interruptions in the flow of traffic, it is possible to use the internal combustion engine 2 switch off. The driver should preferably also be able to decide for himself whether the internal combustion engine 2 may be switched off and can use a switch on the steering wheel for this purpose, for example.

However, information transfer from traffic control systems would also provide support to decide whether it is worthwhile to switch off the engine or whether it makes more sense in terms of energy to keep it running, since the green phase can be expected immediately.

Provided the arrangement of the electric motor 4th with the auxiliary unit 10 and the couplings 18th in connection with the internal combustion engine 2 are designed as separate modules, this can be easily adapted to all types and sizes of internal combustion engines. The module can be designed so that it is even suitable for installation as a retrofit module.

In particular, if the electric motor delivers high outputs in the range of a few kW to approx. 30 kW, the implementation of a high-voltage on-board network is also advisable in order to keep the cabling and contactor costs low compared to a 24V solution. In this case, other functions that go beyond the operation of electrical auxiliary units can also be implemented more easily.

For example, a 230V socket 48 via a current transformer 47 Easier to install and provide sufficient power. It would also be possible to install a 400V three-phase connection. In this way, the usual 230V devices such as entertainment electronics, comfort devices such as refrigerators or microwaves as well as tools and work or construction site machines can be operated.

Furthermore, it would also be possible to operate the vehicle from outside with three-phase current or via a 230V connection while the auxiliary units are in operation 44 to supply. In this way, air conditioning systems in coaches, refrigerated transports, electric winter heating systems, as is common in Scandinavia, can be operated without consuming fuel from the tank of the parked vehicle.

The reference number 40 relates to a further auxiliary unit which, for example, is driven directly by an electric drive, ie electrically driven, such as a water pump or a fan or the like. The reference signs 35 each refer to energy converters which, for example, also convert direct current into alternating current or alternating current into direct current. The reference number 34 identifies an electrical line or a line system.

This in 1 shown supply module or combination module 20th has, as mentioned above, an electric drive 4th and one or more auxiliary units with the required clutches and belts. The combination module and its electrical drive unit are connected to other vehicle systems via the electrical network and are either supplied with energy from them or even emit electrical energy to this system in generator mode.

2 shows a further block diagram of a device according to the invention. Here, too, is the electric motor 4th about straps 26th and 28 and via coupling devices 16 , 18th with the internal combustion engine 2 or the auxiliary unit 10 connectable. At the same time the electric motor gives 4th doses electrical power via power electronics 35 to an electrical memory 38. All of the power electronics and couplings can be via a field bus system 52 can be controlled as in 2 shown. In this case, the control and regulation is carried out by the control device 30th accepted.

The auxiliary unit 10 itself can be part of a vehicle subsystem, for example the air conditioning compressor enables the refrigerant to be circulated in the air conditioning system. To support the compressor running by reducing its torque, a bypass function can be used, for example 56 in the refrigerant circuit via an actuator by the control device 30th to be activated. This is of particular interest in the start-up phases of the internal combustion engine. The reference number 10a identifies the compressor of the auxiliary unit 10 and the reference number 10b the operated device such as the air conditioning system, the cooling system or the like.

With the ancillary equipment system 10 it can also be a compressed air supply with a compressor and compressed air tanks, such as for a compressed air brake in a commercial vehicle. This air compressor can be switched to the "filling the compressed air tank" operating state or to the "conveying into the environment" state via a valve. When the air reservoir is filled, the compressor consumes a lot of power, in contrast to pumping into the open air, which only requires a low idle power. Valves combined with air dryer devices are usually part of a compressed air system. The coupling to the auxiliary unit system could be omitted here, since the flow of energy can be switched off with this actuator or valve, except for a small idle power.

As mentioned above, several auxiliary units can also be provided. These ancillary units are preferably assigned priorities in accordance with their importance. For example, a power steering pump for power steering is given a high priority. An air compressor 10a can temporarily be placed after the power steering pump due to the compressed air reservoir. In this way, further ancillary units can also be operated depending on the vehicle condition with different priorities that may also change depending on the condition. The control device can also classify these priorities 30th be made.

The reference number 37 refers to controllers for controlling or regulating the clutch devices 16 , 18th or the internal combustion engine 2 . The reference number 39 identifies another electric motor, which is an auxiliary unit 40 drives, this electric motor 39 itself is driven electrically and not mechanically. The reference number 42 refers to a 24 V connection.

The applicant reserves the right to claim all of the features disclosed in the application individually or in combination with one another, provided that they are new to the state of the art, individually or in combination.

List of reference symbols

1

contraption

2

Internal combustion engine

3

Output shaft of the internal combustion engine 2

4th

Electric motor

5

Drive shaft of the electric motor

8th

electric power source

10

Auxiliary unit

10a

compressor

10b

powered device

10c

Actuator

16

first coupling device

18th

second coupling device

20th

Supply module

26th

belt

28

belt

30th

Control device

34

management

35

Energy converter

37

Regulator for actuator

39

another electric motor

40

further ancillary unit

42

24 V connection

44

230V connection

47

Power converter

48

230V socket or 400V three-phase socket

52

Field bus system

56

Bypass function

Claims (8)

Motor vehicle and in particular commercial vehicle with an internal combustion engine (2) for driving the motor vehicle, with at least one auxiliary unit (10) and with one (4) which can be supplied with electrical energy at least temporarily from a power source (8), in which the electric motor (4) is at least temporarily connected to the auxiliary unit (10) via a power transmission device (28) in order to drive it, the motor vehicle has a first coupling device (16) by means of which an output shaft (3) of the internal combustion engine (2) can be rotationally connected to a drive shaft (5) of the electric motor (4) and which provides a temporary mechanical drive of the electric motor (4) by the internal combustion engine (2) enables the motor vehicle has a second clutch device (18) which enables the auxiliary unit (10) to be driven by the internal combustion engine (2), so that an air conditioning system in overrun or braking operation directly via the second clutch device (18) and possibly also via belt or Gear wheels are connected to the internal combustion engine (2) in order to use the energy fed back for air conditioning of the motor vehicle, and the electric motor (4) is designed such that the internal combustion engine (2) can be acted upon by the electric motor (4) for support with an additional torque, and / or the electric motor (4) and the internal combustion engine (2) are designed such that the Electric motor (4) supports or substitutes the internal combustion engine (2) in a partial load range of the internal combustion engine (2). Motor vehicle after Claim 1 , characterized in that the auxiliary unit (10) is selected from a group of auxiliary units which contains air compressors, air conditioning compressors, power steering pumps and fans. Motor vehicle according to at least one of the preceding claims, characterized in that several auxiliary units (10) can be driven mechanically by the electric motor (4). Motor vehicle according to at least one of the preceding claims, characterized in that the power source (8) is selected from a group of power sources (8) which include electrical energy stores, fuel cell systems, a steam engine with generator, diesel generator units, exhaust gas turbines with generators, thermocouples or combinations thereof. Motor vehicle according to at least one of the preceding claims, characterized in that the internal combustion engine (2) and the electric motor (4) are designed as a common module (20) for retrofitting. Motor vehicle according to at least one of the preceding claims, characterized in that the auxiliary unit (10) and the electric motor (4) are designed as a common module (20) for retrofitting. Motor vehicle according to at least one of the preceding claims, characterized in that the electric motor (4) serves as a starter for the motor vehicle. Motor vehicle according to at least one of the preceding claims, characterized in that the electric motor (4) serves as an alternator for the motor vehicle.

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