Method and kit for retrofitting a motor vehicle

Abstract

The present invention relates to a method and a kit for retrofitting a motor vehicle which comprises a vehicle transmission having a transmission input and an internal combustion engine, and the internal combustion is coupled or can be coupled to the transmission input.

Description

[0001] Method and kit for converting a motor vehicle

[0002] DESCRIPTION

[0003] The present invention relates to a method for converting a motor vehicle and a kit for converting a motor vehicle.

[0004] Converting motor vehicles is an alternative to developing new vehicles and vehicle platforms. During conversion, only individual components of a vehicle or vehicle platform are replaced. Other components of the vehicle, however, are used in their original form. Conversion can be a very environmentally friendly way to reduce the number of vehicles with environmentally harmful drive systems, such as gasoline and diesel engines. The basic principle is: the more components can be reused, the more worthwhile conversion becomes compared to purchasing or developing new ones.

[0005] Retrofit systems are known in which an additional electric motor is installed in a vehicle powered by an internal combustion engine. One such system is disclosed in WO 2019 / 072926 A1. Since the existing internal combustion engine is retained in this system, the environmental benefit is minimal.

[0006] The object of the invention was therefore to create a conversion option for motor vehicles with combustion engines that provides the greatest possible benefit for the environment and uses as many components and interfaces of the original vehicle as possible.

[0007] This object is achieved by the method according to the invention for converting a motor vehicle and the kit according to the invention for converting a motor vehicle.

[0008] In the method according to the invention for converting a motor vehicle, a motor vehicle is converted that comprises a vehicle transmission with a transmission input and an internal combustion engine, in particular a diesel engine, coupled or capable of being coupled to the transmission input. The method is characterized in that (at least) instead of the internal combustion engine, a hybrid drive system with an internal combustion engine and an electric motor is provided, wherein the electric motor is coupled directly and the internal combustion engine is coupled indirectly to the transmission input.

[0009] A transmission is a gear ratio i between the input (drive) and output (output). The gear ratio i can be defined as the quotient of the output torque and the input torque, or as the quotient of the output speed and the input speed. A direct coupling is understood in particular as a mechanical coupling with a gear ratio i = 1. An indirect coupling is understood in particular as a mechanical coupling with a gear ratio i = 1. With an indirect coupling, the gear ratio can be variable.

[0010] The kit according to the invention is designed to convert a motor vehicle comprising a vehicle transmission with a transmission input and an internal combustion engine coupled or coupleable to the transmission input. The kit has a hybrid drive system comprising an internal combustion engine and an electric motor. The electric motor has an output that can be coupled directly to the transmission input. The internal combustion engine has an output that can be coupled indirectly, in particular via a secondary transmission, to the transmission input. An output is understood in particular to be a mechanical interface at which mechanical power (torque, speed) can be transmitted to another component. The output is preferably a shaft or a hub or another suitable mechanical element.

[0011] Vehicles that are suitable for conversion are often vehicles with diesel engines. Examples include airport apron vehicles, in particular airport tractors, conveyor belt vehicles, container transporters and mobile passenger stairs, as well as small vans. The vehicle to be converted has an existing vehicle transmission that is designed for a speed-torque characteristic curve of the originally intended engine (engine characteristics). Diesel vehicles usually have low speeds and high torques. The inventors recognized that environmentally friendly drive systems, such as a hydrogen rotary piston engine, often do not match these characteristics. However, it has been shown that the inventive combination of an electric motor with a direct connection and an internal combustion engine with an indirect connection makes adaptation to such engine characteristics considerably easier.One reason for this is that electric motors are available in a wide variety of configurations, many of which have a suitable characteristic curve. This makes it easier to find an electric motor that matches the existing transmission. Another advantage is the minimization of losses through a possible additional gear ratio during recuperation. This means that all of the braking energy available at the transmission input can be used for recuperation by the electric motor without further losses. And even in boost mode, in which both the combustion engine and the electric motor deliver power, the drive energy of the electric motor can be used directly. The secondary drive, the combustion engine, is only indirectly connected to the existing transmission, whereby a gear ratio can be provided that takes into account the characteristics of the combustion engine and the existing transmission.

[0012] The internal combustion engine and the electric motor each have a rated power, which is usually specified by the respective manufacturer and can therefore be referred to as NE (rated power of the electric motor) and NC (rated power of the internal combustion engine). From these rated powers, a rated power ratio N can be calculated as follows:

[0013] The nominal power ratio N is preferably between 1:4 and 1:2. In other words, the internal combustion engine preferably has a nominal power NC that is between twice and four times the nominal power of the electric motor NE. With a nominal power ratio in this range, the desired speed / torque behavior of the original diesel engine can be replicated with a suitable selection of the gear ratio (as defined above).

[0014] Within the scope of the method according to the invention, a control unit that controls the internal combustion engine and the electric motor is preferably connected to an existing control system of the motor vehicle, particularly preferably via a single interface, for example in the form of a plug connection. Accordingly, the kit preferably comprises a control unit that is configured to be connected to an existing control system of the motor vehicle via a single interface. This enables a particularly simple connection of the hybrid drive system to the existing motor vehicle. Before the conversion, the control system of the motor vehicle controls, among other things, the internal combustion engine and associated units and receives signals from the components of the motor vehicle.The control unit is therefore preferably configured to translate the signals emanating from the motor vehicle's control system, which are directed to the internal combustion engine, into signals directed to the hybrid drive system, in particular the internal combustion engine and the electric motor. In this case, no modification of the existing control system is necessary.

[0015] Some vehicle transmissions include a torque converter. In advantageous developments, the hybrid drive system is provided instead of the combustion engine and the torque converter. The hybrid drive system thus replaces the combustion engine and the torque converter. In this case, the drive system preferably includes a different torque converter, particularly preferably a torque converter with a lock-up clutch. The lock-up clutch enables a direct mechanical coupling of the input and output sides of the torque converter. This allows the incoming power to be transferred from the transmission output of the vehicle transmission to the electric motor without loss in the event of recuperation. With a torque converter without a lock-up clutch, this is only possible with losses.

[0016] The method according to the invention is preferably carried out using the kit according to the invention. The kit according to the invention is particularly configured for use in the method according to the invention.

[0017] In advantageous developments of the kit, the drive system comprises a primary shaft and a secondary shaft, wherein the primary shaft can be coupled directly and the secondary shaft indirectly to the transmission input. Multiple secondary shafts can also be provided. To simplify the design of the drive system, it is preferably provided that the electric motor is coupled directly to the primary shaft and the internal combustion engine is coupled directly to the secondary shaft. The primary shaft and the secondary shaft can run coaxially or parallel. In the case of multiple secondary shafts, these preferably run parallel to one another. The primary shaft and / or the secondary shaft preferably runs parallel or perpendicular to a direction of travel of the motor vehicle. It is particularly advantageous if the primary shaft runs coaxially to the transmission input. This makes it possible to avoid additional components such as gears.

[0018] For the indirect coupling of the internal combustion engine and transmission input, advantageous developments provide for the output of the internal combustion engine to be connected to the output of the electric motor and / or the primary shaft via a secondary transmission. The use of a secondary transmission makes it possible to combine different electric motors and internal combustion engines, with the secondary transmission being able to be matched to the respective combination. The secondary transmission is preferably a planetary transmission, a spur gear transmission, or a belt-and-chain transmission. Spur gear transmissions and belt-and-chain transmissions are particularly suitable when the primary and secondary shafts run parallel. A planetary transmission is particularly well-suited for a coaxial arrangement of the primary and secondary shafts. In all three cases, the transmission used enables a compact arrangement.

[0019] Depending on the driving condition, it may happen that only the electric motor delivers power. For such cases, advantageous developments provide a separating clutch for selectively separating and coupling the secondary and primary shafts. In a first state of the separating clutch, the secondary shaft and primary shaft are coupled to one another, and in a second state, the secondary shaft and primary shaft are separated from one another. Rotation of the secondary shaft in the second state has no influence on the primary shaft, and vice versa. This prevents braking drag torques from the combustion engine from reducing the efficiency of the hybrid drive system when driving purely electrically. If the electric motor is sufficient in a certain state, the second state is selected on the separating clutch. If the combustion engine is required, the first state is selected.The separating clutch can be located between the internal combustion engine and the secondary transmission, or between the secondary transmission and the primary shaft. In the latter case, losses caused by the movement of parts of the secondary transmission are also avoided. In other words, the separating clutch can be coupled to the secondary transmission at either the input or output.

[0020] The internal combustion engine is preferably a rotary piston engine. Rotary piston engines have a high power density. Since the conversion requires the use of the installation space previously reserved for the internal combustion engine, rotary piston engines are particularly suitable for the hybrid drive system. Furthermore, rotary piston engines feature a modular engine design with individual, serially installed disks. This allows the drive system to be easily adapted to different vehicle types and applications.

[0021] To enable the most environmentally friendly operation of the motor vehicle, the internal combustion engine is preferably a hydrogen internal combustion engine. Compared to other drive types, for example a fuel cell, a hydrogen internal combustion engine is cheaper to manufacture. If a hydrogen internal combustion engine is provided, the kit preferably further comprises a hydrogen tank system connected to the hydrogen internal combustion engine. The hydrogen tank system preferably comprises a hydrogen tank and a hydrogen supply for supplying hydrogen from the hydrogen tank to the hydrogen internal combustion engine. The hydrogen supply has lines and can include various other components, in particular valves, pressure regulators and fuel injectors. The hydrogen tank can be arranged instead of the previous fuel tank and / or at a different location in the motor vehicle.Multiple hydrogen tanks can also be provided. If the hydrogen tank is filled with green hydrogen, CO2-neutral operation of the vehicle is possible in terms of energy consumption. The hydrogen combustion engine is preferably a hydrogen rotary piston engine. Rotary piston engines are well suited for hydrogen combustion, even in smaller sizes.

[0022] The kit preferably has an electrical energy storage device and / or a control unit. The control unit comprises a data storage device on which a program for controlling the internal combustion engine and electric motor, as well as optionally other components of the hybrid drive system, is preferably stored. The electrical energy storage device is preferably designed either for charge maintenance operation without an external power supply / charging option or for plug-in operation (charge level decreases over time) with an external charging option. In the second case, the kit preferably has an interface for charging the electrical energy storage device. This allows the motor vehicle to be operated as a plug-in hybrid after conversion. In the first case, no interface for charging the electrical energy storage device needs to be provided.The energy for temporarily charging the electrical energy storage device is then provided through recuperation during braking and by loading the combustion engine with the electric motor, which can also operate as a generator. During loading, the entire drive system delivers power to propel the vehicle. However, the combustion engine is subjected to greater strain than necessary to drive the vehicle. At the same time, braking is performed with the electric motor. The electric motor then acts as a generator, thereby charging the electrical energy storage device.

[0023] The control unit is preferably configured to receive signals from an accelerator pedal unit and / or sensors of the motor vehicle, in particular from wheel speed sensors including their downstream evaluation electronics, transmission speed sensors, gear detection sensors of the transmission, and temperature sensors, in particular via a single interface with the existing control system of the motor vehicle, and to control the hybrid drive system based on the signals. This allows a driver's input to be forwarded directly to the hybrid drive system, ensuring that the hybrid drive system responds immediately to the accelerator pedal setting. Controlling the hybrid drive system based on other signals, for example based on the brake pedal, would also be possible, but would involve considerably more effort. Controlling based on the accelerator pedal setting has proven to be particularly simple.The control unit is preferably further configured to receive signals from the hybrid drive system, in particular from sensors present therein. Based on these signals, the hybrid drive system can be controlled, for example. The control unit is preferably further configured to transmit signals via the interface to the existing control system of the motor vehicle and thus to control components of the motor vehicle.

[0024] The motor vehicle preferably already has an on-board electrical system and a low-voltage battery prior to the conversion. As mentioned above, the kit according to the invention preferably has an electrical energy storage device. Since electric motors are often operated at a higher voltage than the on-board electrical system of the motor vehicle provides, it is preferably provided that the kit comprises a DC / DC converter that is connected to the electrical energy storage device and connectable to an on-board electrical system of the motor vehicle. The DC / DC converter is preferably configured to convert a high voltage of the electrical energy storage device into a lower voltage of the on-board electrical system, whereby the charge state of the low-voltage battery already present in the vehicle can be maintained without the need for an additional generator (alternator).

[0025] The kit may also include additional components, such as one or more electric assist units that can be connected to a brake booster system of the motor vehicle and / or to a steering assist system of the motor vehicle. Assist units may be, for example, a vacuum pump or an electro-hydraulic pump. In this way, any existing systems of the motor vehicle, such as brake booster and steering assist, can also be used with the hybrid drive system.

[0026] In addition to the internal combustion engine and the electric motor, the control unit can also control other components of the hybrid drive system, such as the secondary transmission, the separating clutch, the hydrogen tank system, the energy storage unit and the electric support unit.

[0027] Furthermore, a converted vehicle with a transmission and a kit according to the above description is disclosed. A motor vehicle to be converted can be understood to mean a motor vehicle that has already been manufactured or a motor vehicle that exists as a vehicle platform. A vehicle platform is understood to mean, in particular, an analog or digital information package on the basis of which a physically existing motor vehicle can be manufactured. In the case of an already manufactured motor vehicle, the method involves removing the internal combustion engine and installing the hybrid drive system. In the case of a vehicle platform, the hybrid drive system is provided instead of the internal combustion engine by first replacing the internal combustion engine with the hybrid drive system in the information package based on the existing vehicle platform and then manufacturing a vehicle based on the vehicle platform.In the case of the vehicle platform, the exchange of the combustion engine and the hybrid drive system takes place before the production of a physically existing vehicle.

[0028] A method is disclosed for converting a motor vehicle in the form of an analogue or digital information package (vehicle platform), which comprises a vehicle transmission with a transmission input and an internal combustion engine, in particular a diesel engine, which is coupled or can be coupled to the transmission input, wherein instead of the internal combustion engine, a hybrid drive system with an internal combustion engine and an electric motor is provided, wherein the electric motor is coupled directly and the internal combustion engine is coupled indirectly to the transmission input by, starting from the existing vehicle platform, first replacing the internal combustion engine in the information package with the hybrid drive system, and then producing a vehicle based on the vehicle platform.

[0029] Furthermore, a method for producing a motor vehicle based on an existing vehicle platform is disclosed, relating to a motor vehicle comprising a vehicle transmission with a transmission input and an internal combustion engine, in particular a diesel engine, coupled to the transmission input. In the method, the vehicle platform is modified by replacing the internal combustion engine with a hybrid drive system comprising an internal combustion engine and an electric motor, wherein the electric motor is coupled directly to the transmission input and the internal combustion engine is coupled indirectly. Subsequently, at least one vehicle is produced based on the vehicle platform.

[0030] The vehicle platform is present, in particular, as a data package on a storage medium, for example, as an entry in a database. Within the scope of the method according to the invention, the database entry is preferably modified, and the combustion engine is replaced by the hybrid drive system. A vehicle is then manufactured based on the database entry.

[0031] The invention is illustrated and explained below by way of example with reference to the drawings. It shows:

[0032] Figure 1 shows a motor vehicle to be converted in a schematic representation,

[0033] Figure 2 shows the motor vehicle of Figure 1 in a schematic representation during

[0034] conversion,

[0035] Figure 3 shows the motor vehicle of Figure 1 in a schematic representation after conversion according to a first embodiment,

[0036] Figure 4 shows the motor vehicle of Figure 1 in a schematic representation after conversion according to a second embodiment,

[0037] Figure 5 shows a motor vehicle in a schematic representation after conversion according to a third embodiment,

[0038] Figure 6 shows a torque-speed diagram,

[0039] Figure 7 shows a combined torque-speed and power-speed diagram.

[0040] Figure 8 is a flowchart of a method for converting a motor vehicle

[0041] The motor vehicle 10 shown in Figure 1 is a vehicle with a conventional internal combustion engine 11, for example a diesel engine, and rear-wheel drive. In addition to the internal combustion engine 11, the motor vehicle comprises a vehicle transmission 12, a fuel tank 13, and a drive train 14. The internal combustion engine 11, vehicle transmission 12, and drive train 14 are coupled to one another, whereby the drive power of the internal combustion engine 11 can be transmitted to the drive train 14 via the vehicle transmission 12. In this way, the rear wheels (not shown) of the motor vehicle 10 shown are driven. For this purpose, the internal combustion engine 11 is coupled to a transmission input 15 of the vehicle transmission 12. The internal combustion engine 11 is powered by fuel, for example diesel, from the fuel tank 13.In a first step of the method according to the invention, the internal combustion engine 11 and other unnecessary components, here the fuel tank 14, are removed from the motor vehicle 10 (see Figure 2).

[0042] Subsequently, a hybrid drive system 100 is provided instead of the internal combustion engine 11 (see Figure 3). The drive system 100 comprises an internal combustion engine 110, an electric motor 120, a secondary transmission 130, and a separating clutch 140. In the embodiment shown, the internal combustion engine 110 is a hydrogen-powered rotary piston engine. The electric motor 120 has a primary shaft 150 directly coupled to the transmission input 15. The primary shaft 150 is the power output of the electric motor 120.

[0043] The internal combustion engine 110 has a secondary shaft 160 as a power output. The secondary shaft 160 couples the internal combustion engine 110 to the secondary transmission 130. A transmission output 132 of the secondary transmission 130 is coupled to the primary shaft 150 via the separating clutch 140. The secondary transmission 130 indirectly couples the secondary shaft 160, and thus the internal combustion engine 110, to the transmission input 15. The primary shaft 150 and the secondary shaft 160 are arranged coaxially one behind the other. Both shafts 150, 160 extend in the direction of travel F of the motor vehicle 10.

[0044] The separating clutch 140 can completely interrupt the connection between the secondary shaft 160 and the primary shaft 150. The internal combustion engine 110 can then no longer deliver power to the drive train 14.

[0045] The drive system 100 is part of a kit 1000, which further comprises a hydrogen tank system 170 with a hydrogen tank 172 and a hydrogen supply 174 for supplying hydrogen from the hydrogen tank 172 to the internal combustion engine 110.

[0046] The kit 1000 further comprises a control unit 180 and an electrical energy storage device 190. The control unit 180 is connected to the electric motor 120, the internal combustion engine 110 and the separating clutch 140 and controls these components.

[0047] Figure 4 shows an alternative embodiment of the hybrid drive system 100. Here, too, for the conversion, starting from a motor vehicle 10 with rear-wheel drive according to Figure 1, the internal combustion engine 11 and the fuel tank 13 were removed (see Figure 2). The hybrid drive system 100 was then provided in place of the internal combustion engine 11. The drive system 100 according to Figure 4 again comprises an internal combustion engine 110 and an electric motor 120 as well as a secondary transmission 130, but no additional clutch. The electric motor 120 again has a primary shaft 150 as a power output. The internal combustion engine 110 again has a secondary shaft 160 as a power output. The primary shaft 150 and the secondary shaft 160 run parallel and in the direction of travel F. The secondary shaft 160 is indirectly coupled to the primary shaft 150 and to the transmission input 15 via the secondary transmission 130.

[0048] Furthermore, a hydrogen tank system 170 with a hydrogen tank 172 and a hydrogen supply 174 for supplying hydrogen from the hydrogen tank 172 to the internal combustion engine 110 is also provided here.

[0049] Figure 5 shows a converted motor vehicle 10 with front-wheel drive. Before the conversion, the motor vehicle 100 had an internal combustion engine (not shown here), a vehicle transmission 12, a fuel tank (not shown here), and a drive train 14. The internal combustion engine and fuel tank were removed. The kit 1000 used for the conversion comprises a hybrid drive system 100 with an internal combustion engine 110 and an electric motor 120, as well as a secondary transmission 130. The internal combustion engine 110 is a hydrogen rotary piston engine. The secondary transmission 130 is a belt transmission.

[0050] The drive system 100 further includes a primary shaft 150 and a secondary shaft 160, which run parallel. The primary shaft 150 is driven directly by the electric motor 120. As a result, the electric motor 120 is directly coupled to the transmission input 15 of the vehicle transmission 12. The internal combustion engine 110 drives the secondary shaft 160, which is connected to the secondary transmission 130 via a separating clutch 140. The output of the secondary transmission 130 is connected to the primary shaft 150. In this way, the secondary shaft 160 is indirectly connected to the transmission input 15.

[0051] The kit 1000 further comprises a hydrogen tank system 170 with a hydrogen tank 172, which is housed here in the rear of the motor vehicle 10. A hydrogen supply line 174 of the hydrogen tank system 170, which includes lines and controllable valves, as well as possibly other elements, connects the internal combustion engine 110 to the hydrogen tank 172. In this way, hydrogen can be supplied to the hydrogen rotary piston engine. Figure 6 shows engine characteristics in the form of three torque curves plotted against the primary shaft speed: a torque curve ME of an electric motor, a torque curve MC of an internal combustion engine, and a combined hybrid torque curve MH. The torque curve ME of the electric motor is constant at the beginning and then decreases. The torque curve MC of the internal combustion engine shows the torque behind the secondary transmission, i.e., the torque already transmitted.The hybrid torque curve MH consists of the sum of the two torque curves ME and MC and therefore shows the total torque of the hybrid drive system over the speed of the primary shaft.

[0052] In this embodiment, the electric motor has a rated power of 40 kW and the internal combustion engine has a rated power of 80 kW. The rated power ratio N is therefore 1:2.

[0053] Figure 7 shows a hybrid power curve PH alongside the identical hybrid torque curve MH. For comparison, a torque curve MO and a power curve PO of the motor vehicle whose internal combustion engine is replaced by the hybrid drive system are also shown. As can be seen, the power curve and the torque curve can be very well reproduced by the hybrid drive system. Particularly with regard to power, the PH and PO curves are almost identical. The motor vehicle can therefore be converted to a hybrid drive system with the selected electric motor and the selected internal combustion engine without requiring any further modifications to the motor vehicle, particularly with regard to the vehicle transmission or drivetrain.

[0054] The method V shown in Figure 8 comprises three steps. First, starting from a motor vehicle comprising a vehicle transmission with a transmission input and an internal combustion engine, in particular a diesel engine, coupled or connectable to the transmission input, the internal combustion engine is removed in a first step S1. In a second step S2, a hybrid drive system with an internal combustion engine and an electric motor is provided instead of the internal combustion engine, wherein the electric motor is coupled directly and the internal combustion engine is coupled indirectly to the transmission input. In a third step S3, a control unit that controls the internal combustion engine and the electric motor is connected to an existing control system of the motor vehicle. Reference symbol I is

[0055] 10 motor vehicle

[0056] 11 Combustion engine

[0057] 12 vehicle transmissions

[0058] 13 Fuel tank

[0059] 14 Powertrain

[0060] 15 Gearbox input

[0061] 100 hybrid drive system

[0062] 110 Internal combustion engine

[0063] 120 electric motor

[0064] 130 secondary gears

[0065] 132 Gearbox output

[0066] 140 Separating coupling

[0067] 150 primary shaft

[0068] 160 Secondary shaft

[0069] 170 hydrogen tank system

[0070] 172 hydrogen tank

[0071] 174 Hydrogen supply

[0072] 180 control unit

[0073] 190 energy storage units

[0074] 1000 Kit

[0075] F Direction of travel

[0076] MC torque curve of an internal combustion engine

[0077] ME torque curve of an electric motor

[0078] MH torque curve of a hybrid drive system

[0079] MO torque curve of a motor vehicle to be converted

[0080] PH power curve of a hybrid drive system

[0081] PO performance curve of a motor vehicle to be converted

[0082] 51 first step

[0083] 52 second step S3 third step

[0084] V Procedure

Claims

Patent claims 1. A method for converting a motor vehicle comprising a vehicle transmission with a transmission input and an internal combustion engine, in particular a diesel engine, coupled or coupleable to the transmission input, characterized in that instead of the internal combustion engine, a hybrid drive system with an internal combustion engine and an electric motor is provided, wherein the electric motor is coupled directly and the internal combustion engine is coupled indirectly to the transmission input.

2. Method according to claim 1, characterized in that a control unit which controls the internal combustion engine and the electric motor is connected to an existing control system of the motor vehicle, preferably via a single interface, for example in the form of a plug connection.

3. Method according to one of the preceding claims, characterized in that the vehicle transmission comprises a torque converter and that the hybrid drive system is provided instead of the internal combustion engine and the torque converter, wherein the drive system preferably comprises a different torque converter, preferably a torque converter with a lock-up clutch.

4. Kit for converting a motor vehicle, which comprises a vehicle transmission with a transmission input and an internal combustion engine coupled or coupleable to the transmission input, with a hybrid drive system comprising an internal combustion engine and an electric motor, wherein the electric motor has an output that can be coupled directly to the transmission input and wherein the internal combustion engine has an output that can be coupled indirectly to the transmission input.

5. Kit according to claim 4, characterized in that that the drive system comprises a primary shaft and a secondary shaft, wherein the primary shaft can be coupled directly and the secondary shaft indirectly to the transmission input, wherein preferably the electric motor is coupled directly to the primary shaft and the internal combustion engine is coupled directly to the secondary shaft, wherein preferably the primary shaft and / or the secondary shaft run parallel or perpendicular to a direction of travel F of the motor vehicle.

6. Kit according to claim 5, characterized in that the primary shaft and the secondary shaft are coaxial or parallel.

7. Kit according to claim 5 or 6, characterized in that the output of the internal combustion engine is connected via a secondary transmission to the output of the electric motor and / or the primary shaft, wherein the secondary transmission is preferably a planetary transmission, a spur gear transmission or a belt transmission.

8. Kit according to one of claims 5 to 7, characterized in that a separating clutch is provided for selectively separating and coupling the secondary shaft and the primary shaft.

9. Kit according to one of claims 4 to 8, characterized in that the internal combustion engine is a rotary piston engine.

10. Kit according to one of claims 4 to 9, characterized in that the internal combustion engine is a hydrogen combustion engine and the kit further comprises a hydrogen tank system connected to the hydrogen combustion engine, wherein the hydrogen tank system preferably comprises a hydrogen tank and a hydrogen supply for supplying hydrogen from the hydrogen tank to the hydrogen combustion engine.

11. Kit according to one of claims 4 to 10, characterized in that that the kit has an electrical energy storage device and / or a control unit which includes a data storage device on which a program for controlling the hybrid drive system, in particular the internal combustion engine and the electric motor, is stored.

12. Kit according to claim 11, characterized in that the control unit is configured to receive signals from an accelerator pedal unit and / or sensors of the motor vehicle and / or from the hybrid drive system and to control the hybrid drive system, in particular the internal combustion engine and the electric motor, on the basis of the signals.

13. Kit according to one of claims 4 to 12, characterized in that the kit comprises a DC / DC converter which is connected to the electrical energy storage device and can be connected to an on-board electrical system of the motor vehicle, wherein the DC / DC converter is configured to convert a high voltage of the electrical energy storage device into a lower voltage of the on-board electrical system.

14. Kit according to one of claims 4 to 13, characterized in that the kit comprises one or more electrical support units which can be connected to a brake booster system of the motor vehicle and / or to a steering support system of the motor vehicle, wherein the support units are preferably vacuum pumps and / or electro-hydraulic pumps.

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