Motor vehicle having a drive train with a laterally arranged internal combustion engine

A motor vehicle (10) has a drive train in the region of a front axle. A body of the motor vehicle has connection points (1, 2, 3) for a laterally arranged internal combustion engine, a vehicle transmission (15) and a torque plate of a motor vehicle (10) that can be driven exclusively by the internal combustion engine. The connection points (1, 2, 3) also are connection points for a hybrid drive train (11). The vehicle uses a modular design principle and can be equipped with differently designed drive systems, including conventional drive exclusively by an internal combustion engine and hybrid drive, without having to make structural modifications. The hybrid drive train may be a serial hybrid or a parallel hybrid.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC 119 to German Patent Appl. No. 10 2011 050 986.0 filed on Jun. 9, 2011, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a motor vehicle having a drive train in the region of a front vehicle axle, having connection points of the drive train in a body of the motor vehicle for a laterally arranged internal combustion engine, a vehicle transmission and a torque plate of a motor vehicle that can be driven exclusively by the internal combustion engine.

2. Description of the Related Art

Motor vehicles with a laterally arranged internal combustion engine have been known for a long time and typically are used for front-wheel drive vehicles. The laterally arranged internal combustion engine disposed at a front part of the vehicle drives the left and right front wheels of the motor vehicle. The internal combustion engine is coupled mechanically and torque-coupled to the vehicle transmission. The transmission has a spur gear stage with two cardan shafts arranged in front of or behind the internal combustion engine relative to the direction of travel of the vehicle and are connected to the transmission, for driving the wheels of the vehicle axle.

This classical connection of the drive train comprising the internal combustion engine and the vehicle transmission has a first connection point between the internal combustion engine and the vehicle body, a second connection point between the transmission and the vehicle body and a third connection point between the drive train and the vehicle body. This third connection point has the function of a torque plate. The first and second connection points support the weight of the components of the drive train.

The connection points for the internal combustion engine and the transmission are two longitudinal members, and the connection point for the torque plate is a crossmember of the motor vehicle.

Hybrid drives for motor vehicles have been developed increasingly developed in recent years. The hybrid drive has a relatively small internal combustion engine and an electric traction motor. The hybrid drive trains may be serial hybrid drive trains or parallel hybrid drive trains.

The object of the invention is to develop a motor vehicle that can be equipped with differently designed drive systems in the manner of a modular design principle without making structural modifications.

SUMMARY OF THE INVENTION

The invention relates to a motor vehicle where connection points for a drive train that can be driven exclusively by the internal combustion engine are the same as those used for the connection of a hybrid drive train.

Irrespective of the design of the hybrid drive train, no connection points are provided for the hybrid drive train other than the connection points needed in a drive train for a motor vehicle that can be driven exclusively by the internal combustion engine, therefore, a classical drive train without a hybrid part. These existing connection points have been used in the hybrid drive train.

The hybrid may be a serial hybrid with an internal combustion engine, a generator, an electric traction motor and a transmission that are coupled mechanically. However, first the internal combustion engine and the generator, and second the electric motor and the transmission are torque-coupled. The serial hybrid has a very compact drive train in which the internal combustion engine drives the generator for generating power and the generated power is delivered to the electrical traction machine. The electrical traction machine drives the wheels via the transmission. The internal combustion engine is small because the drive power of the vehicle is provided by the electric traction motor and the internal combustion engine merely drives the generator. The vehicle also usually has a battery that can supply power to the electric motor.

The hybrid also may be a parallel hybrid with an internal combustion engine, an electric traction motor and a transmission mechanical coupling these components and torque coupling these components. The internal combustion engine and the electric motor of the parallel hybrid jointly act on the input shaft of the transmission. Therefore, the forces of the torques of the internal combustion engine and the electric motor can be provided at the same time at least in an operating state. This allows less stringent design of the electric motor and the internal combustion engine. The internal combustion engine can be smaller than in a vehicle driven exclusively by the internal combustion engine.

All three types of motor vehicles, namely those driven exclusively by combustion power, serial hybrids and parallel hybrids, include a transmission with a spur gear stage having two cardan shafts arranged in front of or behind the internal combustion engine relative to the direction of travel of the vehicle and connected to the transmission for driving an axle, in particular the front axle of the vehicle. Therefore, the classical manner of transmitting force between the transmission and drive shafts is maintained while maintaining the connection points for the drive train in these three concepts.

The same connection points for the three different concepts are selected so that the internal combustion engine is mounted in one longitudinal member of the vehicle, the vehicle transmission is mounted in the other longitudinal member of the vehicle, and the torque plate is mounted in a crossmember that connects the two longitudinal members.

The invention therefore permits the formation of a drive train in a motor vehicle in a modular design system, in particular in a motor vehicle with front-wheel drive. Either a classical front/lateral arrangement of an internal combustion engine is provided for driving the right and left wheel, in particular the right and left front wheel, or, as an alternative, a serial or parallel hybrid version is provided. All three versions use the same three connection points in the vehicle body. These connection points are the classical connection points for the internal combustion engine, the vehicle transmission and the torque plate of a classical lateral arrangement, and particularly a classical front/lateral arrangement of the internal combustion engine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2show the serial hybrid version for the drive concept of a front-axle drive of a motor vehicle10.

The drive train11of the serial hybrid has a small internal combustion engine12, a generator13, an electric traction motor14and a transmission15. The box formed by the dashed line illustrates the drive train11in the region of the front assembly of the motor vehicle10. The transmission15is a spur gear stage having two cardan shafts16arranged behind the internal combustion engine12relative to the direction of travel of the motor vehicle10. However, the cardan shafts16could be in front of the internal combustion engine12. The cardan shafts16are connected to the transmission15, for driving the wheels17of the front axle of the motor vehicle10.

The internal combustion engine12, the generator13, the electric motor14and the transmission15are coupled mechanically and therefore connected to one another to form a unit. Specifically, the internal combustion engine12is connected to one end of the generator13and the transmission15is connected to the other end of the generator. The electric motor14is connected to the end of transmission15averted from the generator. In this serial hybrid, first the internal combustion engine12and the generator13are torque-coupled, and second the electric motor14and the transmission15are torque-coupled. To illustrate this situation, the line18is shown between the generator13and the transmission15inFIG. 1. The internal combustion engine12drives the generator13to generate power. The generated power is delivered to the electric motor14and the electric motor14drives the left and the right wheels17via the transmission15.

The mechanical unit comprising the internal combustion engine12, the generator13, the electric motor14and the transmission15forms the drive train11, is mounted at the connection points1,2and3of the body of the motor vehicle10, as shown inFIGS. 1 and 2. The connection point1is the connection between the drive train11in the region of the internal combustion engine12and the longitudinal member of the vehicle body on the right side relative to the forward direction of travel, while the drive train11in the region of the electric motor14is connected to the left side longitudinal member20in the region of the connection point2. The drive train11is supported at the connection point3by a crossmember (not illustrated in any more detail) that connects the two longitudinal members19and20. The connection point3is between the two longitudinal members19and20. Since the crossmember is not visible in the illustration ofFIG. 1, the connection point3is illustrated relative to the lateral extent of the vehicle, but is situated behind the transmission15.FIG. 2, however, schematically illustrates the connection point3between the transmission15and the crossmember.

The connection points1and2function to support the weight of the drive train11, while the connection point3functions to receive the torque introduced into the vehicle body via the drive train11and therefore serves as the torque plate.

The internal combustion engine12, which is a small internal combustion engine on account of the function of a so-called range extender, and the electric motor14are torque-decoupled, the drive train11can be formed so that an offset is possible between the crankshaft of the internal combustion engine12and the output shaft of the electric motor14. Thus, the drive train11can have a lower center of gravity and permits a variable package overall.

The connection points1,2and3for supporting the drive train11of the described serial hybrid correspond to those of a conventional vehicle that is driven exclusively by an internal combustion engine12and that has a drive train formed by the internal combustion engine12and the transmission15. The conventional drive train is illustrated schematically inFIGS. 3 and 4.

As an alternative to the conventional vehicle and serial hybrid, a drive train for a parallel hybrid also can be supported readily without any change to the connection points1,2and3, as shown inFIGS. 5 and 6. The parallel hybrid has an internal combustion engine12, an electric traction motor14and a transmission15, with these components being mechanically coupled and torque-coupled. The generator can be dispensed with in principle. However, the electric motor14preferably is in the form of an electrical machine. The electrical machine14can operate both in motor mode to act as a traction motor and in generator mode to generate electrical energy and to supply said electrical energy to a battery. The battery functions to supply power to the electrical machine in motor mode.

All three of the described versions—conventional vehicle which is driven exclusively by means of the internal combustion engine, serial hybrid, and parallel hybrid—use the same connection points1,2and3in the vehicle body.