1. Field of the Invention
The present invention is in the field of vehicular power plants and more specifically relates to a type of power plant in which an internal combustion engine operates a generator that charges a battery pack, while simultaneously, a steam engine using waste heat from the internal combustion engine operates a second generator that also charges the battery pack. There is no mechanical connection between either engine and the drive wheels, the drive wheels being driven by electric motors powered by the battery pack.
2. The Prior Art
In U.S. Pat. No. 4,405,029 issued Sept. 20 1983, Hunt shows a vehicle that has an electric motor as well as an internal combustion engine that may selectively be connected to drive the wheels of the vehicle, either independently or together. At speeds above 20 mph, the internal combustion engine drives the wheels, and heat from the engine is used to generate electric power that is stored in the battery. Below 20 mph, the wheels are driven by an electric motor powered by the battery, although the internal combustion engine may be used to assist. This differs from the present invention in that, in the present invention the battery-powered electric motor always drives the wheels and the gasoline engine never directly drives the wheels but only operates a D.C. generator.
In U.S. Pat. No. 4,470,476 issued Sept. 11, 1984, which is a divisional of the aforementioned U.S. Pat. No. 4,405,029, Hunt shows another embodiment of his invention, in which radiant energy of the waste heat and exhaust gases from the internal combustion engine are converted directly to electrical energy by means of photovoltaic cells which are used to charge the battery. In contrast, the present invention does not use photovoltaic cells.
In U.S. Pat. No. 4,109,743, Brusaglino et al. describe a vehicle propulsion system in which a turbine drives two counter rotating flywheels that in turn drive two D.C. generators. These D.C. generators power electric motors that turn the drive wheels. In this system the energy is stored in the flywheels rather than in a battery pack, and no batteries are used in the system.
In U.S. Pat. No. 4,394,582, Kreissl et al. show a method and apparatus for using the waste heat energy from an internal combustion engine. In their system, a turbine is driven by exhaust gases from the internal combustion engine, and the turbine drives a generator. The generator connected through an electrical converter to an electric motor which is drivingly coupled to the internal combustion engine to help it to overcome its load. The turbine needs to turn very fast (120,000 rpm) and so it is necessary to use a "synchronous" type of rotor. Thus, Kreissl et al. use waste heat as a way of mechanically assisting the internal combustion engine that is connected to the drive wheels of the car.
In U.S. Pat. No. 4,570,077 issued Feb. 11, 1986 to Lambley, there is shown a waste heat recovery system in which the waste heat from the main engine heats a boiler that drives a turbine that is used to drive an alternator. When there is not enough waste heat, a hydraulic drive powered by the main engine is clutched to the alternator rotor shaft to turn it.
In U.S. Pat. No. 4,433,548 issued Feb. 28, 1984 to Hallstrom, Jr. there is described an engine that is a combination internal combustion engine and steam engine, and in which the hot exhaust gases resulting from the power stroke of the internal combustion engine are used to generate steam that is used to provide a second power stroke.
In the latter three patents described above, the wheels of the automobile are driven by an internal combustion engine, while in contrast, in the present invention the wheels are always driven by a D.C. drive motor powered by a battery. The battery, in turn, is charged by a first D.C. generator powered by an internal combustion engine and by a second D.C. generator powered by a steam engine that is heated by waste heat from the internal combustion engine.