HYBRID ROAD VEHICLE

The present invention relates to a hybrid road vehicle, in particular a low-weight passenger-carrying vehicle.

The extensive increase of the personal mobility nowadays results in a division of the motor traffic into basically two very different fields, one of which is the traffic within inhabited areas, whereas the other one is the traffic outside inhabited areas.

Within inhabited areas, motion of a vehicle is mostly characterised by a frequently changing, but low speed, that does not usually exceed the rate of 50 km/h, a relatively frequent directional change, as well as frequent accelerating and breaking actions, while outside inhabited areas, a high speed, which may reach even the rate of 130 km/h, and a much more steady motion with less frequent directional change, breaking and acceleration relative to the former case appear to be general.

These two traffic conditions raise completely different requirements for a vehicle. Within inhabited areas, it seems to be optimal for a vehicle to have a low weight that requires low engine power at low speeds and allows to obtain a great portion of the accelerating energy from recuperation of the breaking energy. Outside inhabited areas, however, the high engine power is typical and at the same time, the weight of the vehicle and: the scale of the energy recuperation are of less importance.

Because of the different requirements mentioned above, ^• even more hybrid vehicle driven by different energy sources has been developed up to now. Several variants of such vehicles have been introduced in the patent literature, for example in the patent specifications EP 0 678 414, DE 102 46 839 and US 5 799 744. The first one of the serially manufactured hybrid passenger cars was the Toyota Prius, and the later designs of such hybrid vehicles have had more or less the same construction, i.e. an electric motor-generator with an associated battery is connected to the internal combustion engine in a serial or

a parallel fashion. Due to this concept, this type of vehicles has significant advantages, mainly in the traffic within inhabited areas. In the case of a cold- start or during pacing forward in heavy traffic, the electric motor-generator plays the main role, thereby the fuel consumption and the emission have been substantially reduced. On the other hand, the internal combustion engine can work in cycles of higher efficiency since a suddenly increased power requirement is covered by the high torque of the electric motor, wherein the torque is rather high even at a very low rate of revolution. If the vehicle is equipped with a so called start-stop automatics, the internal combustion engine may be stopped, for example, in the case of waiting at a traffic lamp. A substantial portion of the breaking energy is, however, fed back into the battery.

An object of the present invention is to provide a solution for supporting both of the two different traffic conditions described above in a more optimal, more economic and more environment friendly manner than before by an energetic utilisation of the parking time, on the one part, and by the use of mechanical energy produced by the human force, on the other part.

The present invention is based on the recognition that the different traffic conditions require different types of driving systems, i.e. for the low speeds, the parking manoeuvres and the restarts in urban areas, electric energy and human force are needed that practically result in no direct environment pollution, whereas for the high speeds on the highways, an internal or external combustion engine is preferred. An analysis of the two traffic conditions has led to , the further recognition that during the parking periods, the overall duration of which is longer of several order than the time that' the vehicle spends in the traffic, the buttery of the vehicle can be charged by solar energy that, in addition to the mechanical source of driving provided by the passengers of a vehicle having a relatively low weight, may cover the whole energy consumption required for the everyday traffic within the inhabited areas. Outside the inhabited areas, the internal or external combustion engine is also activated to reach the required speed.

To achieve the above objects, a hybrid vehicle according to the present invention has, in addition to the internal or external combustion engine and the electric motor-generator, a mechanical system for driving the vehicle by the human force, as a third driving means, and a solar cell unit arranged on the surface of the vehicle's coachwork, in particular on the top surface thereof, and adapted to charge the battery. The mechanical driving system is preferably a pedal drive.

In a preferred embodiment of the hybrid road vehicle according to the invention, the units of the triple drive, i.e. the internal or external combustion engine, the electric motor-generator and the mechanical drive using human force, are mechanically connected to each other through transmission units and/or said units of the triple drive are electrically connected to each other through charging generators.

The vehicle according to the present invention is 'preferably manufactured of modern, lightweight, high-strength materials, in particular of carbon fibre composite material or, in certain cases, partly of aluminium-magnesium alloys. It is preferred that the coachwork has an aerodynamic shape and the engine is a power source that preferably uses regenerative energy, like vegetal alcohol or vegetal oil. In a preferred embodiment of the hybrid vehicle according to the present invention, the interior of the vehicle is equipped with seats designed for the pedal-drive, in particular with seats used on chafr-bikes.

The fuel consumption and the inherent emission of the vehicle equipped with such a triple hybrid drive are as low as 15-20% of the fuel consumption and the emission of the modem vehicles of today. Furthermore, this type of hybrid vehicle is capable of travelling even without producing any noise or emission.

The present invention will be better understood through a detailed description of a preferred embodiment thereof by referring to the accompanying drawings, in which:

Figure 1 is a schematic side view of the road vehicle equipped with a triple hybrid drive, according to an embodiment of the present invention, and

Figure 2 is a schematic plan view of the drive chain of the vehicle shown in Figure 1.

As shown in Figure 1 , the road vehicle equipped with a triple hybrid drive according to the present invention is provided with high efficiency solar cells on its top surface, said solar cells constituting a solar cell unit 1 connected to a battery 2 with a high energy density in it. The aerodynamically shaped coachwork and the framework of this hybrid road vehicle are made of modern, lightweight, high-strength materials, in particular of a carbon fibre composite material or, in certain cases, partly of an aluminium-magnesium alloy so that the vehicle has the lowest possible weight in addition to the required strength.

The battery 2 is accommodated preferably behind the driver's or the passenger's seat, and it is charged with the energy captured by the solar cell unit 1 , preferably while the vehicle is parked.

The electric motor-generator 3 is supplied by the electric energy accumulated in the battery 2. The electric motor-generator 3 can be used alone for driving the hybrid vehicle but it can be also used, if necessary, to assist the pedal drive 4 actuated by the driver and/or the passenger, said pedal drive 4 generally being adequate to the low speeds in the urban traffic as well as being healthy in today's life characterized by the lack of exercise. The pedal drive 4 is connected to the driven shaft of the vehicle preferably through an automatic transmission unit 5 and a differential gear unit 6. The shaft is also driven by the electric motor-generator 3 or an internal or external combustion engine 8 through another automatic transmission unit 7 and the differential gear unit 6. The internal or external combustion engine 8 is mainly used outside inhabited areas thus allowing the vehicles of today to reach a common travelling speed.

Alternatively, both of the pedal drive and the internal or external combustion engine drive a respective generator and those together with the energy

accumulated in the battery may be used to drive electric wheel-hub motors that operate as electric generators at breaking.