Hybrid vehicle

Abstract

A hybrid motor vehicle (1) comprising an internal combustion engine (3), an electric motor (2), an interior air conditioning device (12), a catalytic converter (6) associated with the internal combustion engine (3) and having a catalyst heating device (7) operable at a first voltage, in particular 48V, from a medium-voltage network (9), a high-voltage network (4) to which the electric motor (2) is connected, at a second voltage that is higher than the first voltage, a voltage converter (8) for converting the second voltage into the first voltage, a heat exchange device (10) for heating a temperature control medium of the interior air conditioning device (12) circulating in a temperature control circuit (11) using waste heat from the internal combustion engine (3), and a control device (19) for operating the catalyst heating device (7) as a function of the operation of the internal combustion engine (3), characterized in thatthat an air conditioning heating device (16) of the interior air conditioning device (12) operating at the first voltage is connected to the medium-voltage network (9), wherein the control device (19) is designed to operate the air conditioning heating device (16) from the medium-voltage network (9) at least when the internal combustion engine (3) and / or the catalyst heating device (7) are not operated, wherein the control device (19) is designed to exclusively operate the catalyst heating device (7) or the air conditioning heating device (16) in at least two first operating modes, so that when the internal combustion engine (3) is switched off and the electric motor (2) is being used, the air conditioning heating device (16) can be operated, whereas when the internal combustion engine (3) is operating and supplying waste heat, exclusively the catalyst heating device (7) can be used.

Description

[0001] The invention relates to a hybrid motor vehicle, comprising an internal combustion engine, an electric motor, an interior air conditioning device, a catalytic converter assigned to the internal combustion engine with a catalyst heating device operable at a first voltage, in particular 48 V, from a medium-voltage network, a high-voltage network to which the electric motor is connected, at a second voltage which is higher than the first voltage, a voltage converter for converting the second voltage into the first voltage, a heat exchanger device for heating a temperature control medium of the interior air conditioning device circulating in a temperature control circuit by waste heat from the internal combustion engine and a control device for operating the catalyst heating device as a function of the operation of the internal combustion engine.

[0002] Hybrid vehicles are characterized by the fact that their drivetrain incorporates both a conventional combustion engine and an electric motor, which can be used both generatively and for propulsion. The electric motor is typically connected to the hybrid vehicle's high-voltage network, the high voltage of which can be more than 200 V, for example, 450 V. The high-voltage network typically also includes a high-voltage battery from which the electric motor can be powered. In so-called plug-in hybrid vehicles, the hybrid vehicle also includes a charging device that allows the high-voltage battery to be charged, for example, via a suitable charging station, a wall box, and / or a standard household connection.

[0003] Internal combustion engines in modern motor vehicles are usually equipped with catalytic converters for exhaust gas treatment. Such catalytic converters begin to operate effectively when a certain operating temperature is reached. To allow effective use of the catalytic converter even at low temperatures, for example, immediately after starting the internal combustion engine, it has been proposed to equip the catalytic converter with a catalyst heating device, which can be designed, for example, as a heating disc. Such a heating disc consists of a wound metal carrier that can be energized as needed and is installed in the catalytic converter housing.

[0004] The desirable heating output of such catalyst heaters can be in the range of several kilowatts, for example, 4 kW. However, conventional vehicle electrical systems usually only provide a low voltage of 12 V, so that an extremely high current supply would be required to operate the catalyst heater accordingly, resulting in a corresponding design that is expensive and difficult to implement. Therefore, it has been proposed, at least for hybrid vehicles, to operate the catalyst heater at a medium voltage (intermediate voltage), in particular at 48 V. This medium voltage can be provided, for example, from the high-voltage network of the electric motor via a suitable voltage converter and allows the use of lower current intensities, thus significantly reducing the demands on the catalyst heater and its supply lines.Such a design can be found, for example, in DE 198 04 098 A1. According to DE 10 2012 209 202 A1, an alternative approach was proposed to use a regenerative braking system to provide the energy for heating a motor vehicle catalytic converter.

[0005] Hybrid vehicles also typically have interior air conditioning systems, which are designed in particular to heat the interior to a comfortable temperature, in particular one that can be selected by the occupants. For this purpose, it is known in conventional motor vehicles with only an internal combustion engine to transfer waste heat from the internal combustion engine via a heat exchanger to a temperature control circuit using, for example, cooling water or, if necessary, air to be supplied directly to the interior in order to provide the desired heating. In hybrid vehicles, however, no waste heat is generated for heating the interior, at least when the hybrid vehicle is running purely on electricity. Accordingly, it has been proposed to operate the temperature control medium, in particular cooling water, in the temperature control circuit by means of a high-voltage resistance heater, in particular a high-voltage PTC, powered by the high-voltage grid.Such a high-voltage heating device does not need to be operated whenever the combustion engine generates corresponding waste heat, which is also dissipated via the water of the temperature control circuit, which also serves to cool the combustion engine.

[0006] In addition to such possibilities for heating a temperature control medium, the heat of which is in turn used to heat the air to be supplied to the interior, in particular by means of a heat exchanger, interior air conditioning systems for known hybrid motor vehicles often also have a low-voltage heating system operated in the 12 V vehicle electrical system for the air to be supplied to the interior, which is operated from the low-voltage vehicle electrical system and cannot itself provide sufficient power to provide sufficient, desired heat, but can be used for initial heating of the air when the combustion engine is cold and / or for readjusting / supplementing the heating activity at later times.

[0007] The known designs of hybrid vehicles have the problem that the high-voltage heating device requires an additional component which, in terms of design and safety requirements, is complex and requires a lot of space, and which cannot always be integrated into the vehicle structure in current hybrid vehicles, or can only be integrated with compromises.

[0008] EP 2 000 366 A2 relates to a control device for a vehicle having a high-voltage battery, a charging port for the high-voltage battery, a cooling and heating load, and a load for warming up the engine. The control device controls the electrical loads in the motor vehicle depending on the disconnection of a charging cable from the charging port. In this way, the timing for preparing the vehicle is to be improved. According to the specific exemplary embodiment, a hybrid vehicle has an internal combustion engine, a motor generator, a battery, a charging port, and an internal vehicle electrical load. The internal vehicle electrical load includes not only the motor generators and the associated power electronics and the cooling and heating load (air conditioning system), but also the load for warming up the engine, which can be fed by an auxiliary battery. The load can be a catalyst heater.The catalyst heater is operated when the charging connection is disconnected.

[0009] DE 10 2018 111 259 A1 relates to a preconditioning system for a hybrid electric vehicle, in which the temperatures of the battery, cabin, and catalyst are preconditioned in response to a predicted vehicle start time and / or a detected action indicating a probability of HEV start. Preconditioning temperatures are achieved at rates set according to the power availability of a battery and an external power source, while also learning from changes in actual start times and driver actions.

[0010] DE 10 2017 126 091 A1 relates to a method for operating a hybrid vehicle, wherein it is also determined whether an engine start of an internal combustion engine is imminent and a catalyst for the internal combustion engine is heated when the engine start is determined.

[0011] DE 10 2007 037 350 A1 discloses a method for operating a drive device of a vehicle, which comprises an internal combustion engine, to which at least one exhaust gas catalyst is assigned, and at least one electric machine, to which at least one energy storage device is assigned. It is provided that the exhaust gas catalyst is electrically heated to reach a predetermined minimum temperature.

[0012] The invention is therefore based on the object of providing a hybrid motor vehicle which is improved compared to the aforementioned, in particular with regard to the required components and the installation space requirement.

[0013] To achieve this object, in a hybrid motor vehicle of the type mentioned at the outset, the invention provides that an air conditioning heating device of the interior air conditioning device operating at the first voltage is connected to the medium-voltage network, wherein the control device is designed to operate the air conditioning device from the medium-voltage network at least when the internal combustion engine and / or the catalyst heating device are not operated, wherein the control device is designed to exclusively operate the catalyst heating device or the air conditioning heating device in at least two first operating modes, so that when the internal combustion engine is switched off and the electric motor is used, the air conditioning heating device can be operated, whereas when the internal combustion engine is operated and supplies waste heat, exclusively the catalyst heating device can be used.

[0014] The invention takes advantage of the fact that, particularly in research into replacing conventional 12V electrical systems with 48V electrical systems, air conditioning heating devices for air to be introduced into the interior of the motor vehicle have already been developed, which can therefore operate with an operating voltage of 48V, which preferably corresponds to the first voltage (medium voltage). According to the invention, it has now been recognized that if a first voltage, which lies between the second voltage (high voltage) of the high-voltage network and the third voltage (low voltage) of a low-voltage network (on-board electrical system), is already present, in this case to operate a catalytic converter heating device, this can also be used to operate such an air conditioning heating device replacing a 12V heating device at the first voltage.This is particularly true given the further finding that the air conditioning heating system is not needed precisely when the catalytic converter heating system is in operation, since the combustion engine then provides waste heat. On the other hand, the catalytic converter heating system is usually not needed, or only at very low power, when the electric motor, which does not provide waste heat, is used, meaning that the air conditioning heating system of the interior air conditioning system is needed to provide the desired interior heating. In other words, the first voltage is also present in the medium-voltage network when the electric motor is operated by the voltage converter, even when the catalytic converter heating system is not needed (or only to a very small extent), so that ultimately the voltage converter can be used for another purpose to provide the first voltage from the second voltage.

[0015] In the hybrid motor vehicle according to the invention, which in particular further has an on-board electrical system at a third voltage which is lower than the first or the second voltage, in particular 12 V, the fact of the availability of a medium voltage, namely the first voltage lying between the second voltage and the third voltage, is therefore exploited in order to provide a replacement means for the conventional 12 V heating device of the interior air conditioning device and the high-voltage heating device for the temperature control means, which provides sufficient heating power for heating the air to be supplied to the interior of the motor vehicle at a sufficiently low current intensity, so that by providing the air conditioning heating device operable at the first voltage, the high-voltage heating device which was operated at the second voltage of the high-voltage network, in particular the high-voltage PTC heater, can also be omitted.This in turn means that a significant reduction in costs and weight is possible and more free space is provided in the hybrid vehicle for other components or as space that can be used by the occupants.

[0016] Since the present invention is used with particular advantage in a plug-in hybrid motor vehicle (PHEV - Plug-In Hybrid Electric Vehicle), it is of course also possible to provide for use in other hybrid motor vehicles, for example in mild hybrids using a 12V electrical system.

[0017] Within the scope of the present invention, there are essentially two operating scenarios. In a first operating state, the combustion engine is switched off or cold, and the hybrid vehicle runs electrically using the electric motor. The combustion engine then generates no waste heat for heating the interior of the hybrid vehicle, as the hybrid vehicle runs purely on electricity. Heating the catalytic converter is not necessary, as the combustion engine does not produce exhaust gases that would need to be cleaned. The entire power can then be used for the air conditioning heating system via the voltage converter to heat the interior.

[0018] In a second operating state, the combustion engine is switched on or warm, so that waste heat is generated through combustion, which is dissipated via the temperature control circuit, particularly the cooling water, and heats the interior of the vehicle via, for example, a heat exchanger of the interior air conditioning system. The voltage converter therefore does not need to be used for interior heating, so it is in operation for heating the catalytic converter via the catalytic converter heating system and heats the catalytic converter as quickly as possible to enable rapid catalytic converter effectiveness.

[0019] The control device naturally operates in accordance with the user-specific specifications of the interior air conditioning system, for example a selected, desired interior temperature.

[0020] As already indicated, the air conditioning heating device is particularly advantageously an air conditioning heating device designed for heating air to be introduced into an interior space to be heated. The air to be introduced into the interior space to be heated can thus be heated either by means of the temperature control circuit, in particular from the cooling water of the combustion engine, or via the air conditioning heating device operated at the first voltage. In particular, the interior air conditioning device can thus further comprise a further heat exchanger device for transferring heat from the temperature control medium heated by the engine's waste heat to the air for heating the interior space.

[0021] The air conditioning heating device can particularly advantageously be or comprise a resistance heater, in particular a PTC heater (PTC - "Positive Temperature Coefficient"). As already mentioned, such air conditioning heating devices have already been developed for motor vehicles that use a 48V electrical system instead of a 12V electrical system, so that the corresponding components can now be used as identical parts both in the hybrid vehicle according to the invention and in motor vehicles that generally operate with a 48V electrical system.

[0022] As already mentioned, the control device is designed for the exclusive operation of the catalyst heating device or the air conditioning heating device in at least two first operating modes. According to the invention, this means that when the internal combustion engine is switched off (and in particular cold) and the electric motor is being used, the air conditioning heating device can be operated, whereas when the internal combustion engine is operating and providing waste heat, only the catalyst heating device can be used. Within the scope of the present invention, however, it is also conceivable for the control device to be designed for the simultaneous operation of the catalyst heating device and the air conditioning heating device from the medium-voltage network in at least one operating mode.This means that a hybrid of the operating states discussed above is conceivable, in which, for example, the catalytic converter is kept warm while, at the same time, the interior is heated by means of the air conditioning heating system. The voltage converter must be dimensioned accordingly in terms of its output power, for example to operate both heating systems, possibly with reduced but sufficient heating output in each case. Specifically, it can be provided, for example, that the control device is designed to operate the catalytic converter heating system with reduced heating output in the second operating mode in order to maintain a minimum temperature of the already heated catalytic converter. In this case, the corresponding second operating mode would be a type of keep-warm mode, which can lead to overall energy savings.

[0023] To enable appropriate use of the catalyst heating device and the air conditioning heating device, the control device can have at least one switching device for switching power supplies to the catalyst heating device and the air conditioning heating device. For example, the at least one switching device can be connected downstream of the voltage converter. The switching device can also be implemented outside the control device if it is not considered part of the control device.

[0024] Further advantages and details of the present invention will become apparent from the exemplary embodiments described below and from the drawings. Fig. 1 a hybrid motor vehicle according to the invention in a first operating state, and Fig. 2 the hybrid motor vehicle according to the invention in a second operating state.

[0025] Fig. Figure 1 shows a schematic diagram of a hybrid motor vehicle 1 according to the invention. This vehicle has both an electric motor 2 and an internal combustion engine 3 in its drive train. The electric motor 2 is connected to a high-voltage network 4, which is at a second voltage (high voltage). A high-voltage battery 5 is also connected to the high-voltage network 4, which can be charged via a charger (not shown in detail), so that the hybrid motor vehicle 1 is a plug-in hybrid vehicle.

[0026] A catalytic converter 6 is assigned to the internal combustion engine 3, which has a catalytic converter heating device 7, designed here as a heating disk. The catalytic converter heating device 7 is to be operated at a first voltage (medium voltage), which is obtained by means of a voltage converter 8 from the second voltage of the high-voltage network 4, so that the voltage converter 8 thus provides the first voltage for a medium-voltage network 9. The hybrid motor vehicle 1 also has an on-board electrical system (low-voltage network), not shown in detail for the sake of clarity, whose third voltage is lower than the first voltage and the second voltage. In one example, the first voltage can be 48 V, the second voltage 450 V, and the third voltage 12 V.

[0027] The internal combustion engine 3 is further coupled to a temperature control circuit 11 via a heat exchanger device 10, so that waste heat from the internal combustion engine 3 can be used during operation to heat a temperature control medium, in this case cooling water. By means of a further heat exchanger device 13, this heat can be used in an interior air conditioning device 12 to heat air to be supplied to the interior of the motor vehicle 1. This interior air conditioning device 12 accordingly comprises an air source 14 for outside air and / or recirculated interior air, as well as a distribution device 15 for distributing the heated air in the interior of the hybrid motor vehicle 1 in order to achieve its heating.

[0028] In the present case, however, the interior air conditioning system 12 also includes an electric air conditioning heating system 16, which can also be used to heat the air supplied to the interior. The air conditioning heating system 16 is designed as a PTC heater and is also operated at the first voltage generated by the voltage converter 8, here 48 V. Via switching devices 17, 18 of a control device 19, which may also include a control unit 20, schematically indicated here, both the catalyst heating system 7 and the air conditioning heating system 16 can be supplied with current and thus corresponding electrical power by the voltage converter 8.

[0029] In both the Fig. 1 and Fig. 2, the interior is now to be heated, which can be selected, for example, via a corresponding control device by an occupant of the hybrid vehicle 1. In the first operating state according to Fig. 1, the internal combustion engine 3 is not in use and is cold. The electric motor 2 is used for driving. Accordingly, no heat is released to the temperature control circuit 11, so that the additional heat exchanger device 13 cannot be used to heat the air from the air source 14 that is to be supplied to the interior of the motor vehicle 1. On the other hand, no exhaust gases are produced, so that the catalytic converter 6 does not need to be heated and thus the catalytic converter heating device 7 does not need to be operated. As shown by the switching devices 17 and 18, the control device 19 is designed to supply current, in this case exclusively, to the air conditioning heating device 16 in this operating state, so that despite the absence of waste heat from the internal combustion engine 3, air can be heated according to arrow 21 by means of the air conditioning heating device 16 (see arrow 22), and can be discharged to the interior of the motor vehicle 1 via the air distribution device 15 (see arrows 23).For this purpose, a high-voltage heating device for the cooling water of the temperature control circuit 11 is not required, as is the case with conventional hybrid vehicles.

[0030] Fig. 2 shows a second operating state in which the combustion engine 3 is operating and waste heat is thus introduced into the temperature control circuit 11 according to arrow 24. Thus, in this case (see arrows 25 and 26), the air to be introduced into the interior can be heated by means of the additional heat exchanger device 13, while the air conditioning heating device 16 (see the position of the switching device 17) is not operating. Instead, the catalyst heating device 7 (see the position of the switching device 18) is supplied with electrical power by the control device 19 from the voltage converter 8 to heat the catalyst 6.

[0031] In addition to the Fig. 1 and Fig.2, in which either the air conditioning heating device 16 or the catalyst heating device 7 is operated exclusively, mixed states are also conceivable, for example, operation of the catalyst heating device 7 at reduced power in order to maintain a certain minimum temperature, while simultaneously heating air for the interior by the air conditioning heating device 16. Other such second operating modes can of course also be implemented accordingly by the control device 19.

Claims

[1] A hybrid motor vehicle (1) comprising an internal combustion engine (3), an electric motor (2), an interior air conditioning device (12), a catalytic converter (6) associated with the internal combustion engine (3) and having a catalyst heating device (7) operable at a first voltage, in particular 48V, from a medium-voltage network (9), a high-voltage network (4) to which the electric motor (2) is connected, at a second voltage higher than the first voltage, a voltage converter (8) for converting the second voltage into the first voltage, a heat exchange device (10) for heating a temperature control medium of the interior air conditioning device (12) circulating in a temperature control circuit (11) by waste heat from the internal combustion engine (3), and a control device (19) for operating the catalyst heating device (7) as a function of the operation of the internal combustion engine (3), characterized byin that an air conditioning heating device (16) of the interior air conditioning device (12) operating at the first voltage is connected to the medium-voltage network (9), wherein the control device (19) is designed to operate the air conditioning heating device (16) from the medium-voltage network (9) at least when the internal combustion engine (3) and / or the catalyst heating device (7) is not operated, wherein the control device (19) is designed to exclusively operate the catalyst heating device (7) or the air conditioning heating device (16) in at least two first operating modes, so that when the internal combustion engine (3) is switched off and the electric motor (2) is being used, the air conditioning heating device (16) can be operated, whereas when the internal combustion engine (3) is operating and supplying waste heat, exclusively the catalyst heating device (7) can be used. [2] Hybrid motor vehicle (1) according to claim 1, characterized by that the hybrid motor vehicle (1) further comprises an on-board electrical system at a third voltage which is lower than the first and the second voltage, in particular 12 V. [3] Hybrid motor vehicle (1) according to claim 1 or 2, characterized by that the air conditioning heating device (16) is designed to heat air to be introduced into an interior space to be heated. [4] Hybrid motor vehicle (1) according to claim 3, characterized by that the interior air conditioning device (12) further comprises a further heat exchange device (13) for transferring heat from the temperature control medium heated by the waste heat of the internal combustion engine (3) to the air for heating the interior. [5] Hybrid motor vehicle (1) according to one of the preceding claims, characterized by that the air conditioning heating device (16) is or comprises a resistance heater, in particular a PTC heater. [6] Hybrid motor vehicle (1) according to one of the preceding claims, characterized by that the control device (19) is designed in at least one second operating mode for the simultaneous operation of the catalyst heating device (7) and the air conditioning heating device (16) from the medium-voltage network (9). [7] Hybrid motor vehicle (1) according to claim 6, characterized by that the control device (19) is designed in the second operating mode to operate the catalyst heating device (7) with reduced heating power in order to maintain a minimum temperature of the already heated catalyst (6). [8] Hybrid motor vehicle (1) according to one of the preceding claims, characterized by that the control device (19) has at least one switching device (17, 18) for switching power supplies to the catalyst heating device (7) and the air conditioning heating device (16). [9] Hybrid motor vehicle (1) according to one of the preceding claims, characterized by that the hybrid motor vehicle (1) is designed as a plug-in hybrid motor vehicle (1).

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