Field of the Invention

This invention relates to hybrid electric vehicles and in particular electric vehicles where the primary motive force applied to the vehicle's wheels is provided by at least one electrical motor, and wherein a highly efficient combustion engine is utilised to generate electricity that either directly supplies electrical power to the electric motor, or replenishes the store of electrical power that is consumed by the operation of the vehicle.

Background of the Invention There has been increasing interest in systems for hybrid electric vehicles in recent years. These types of vehicles have the advantage of offering exceptional fuel efficiency and significantly lower emissions. They also reduce the fuel costs for the operator. One of the problems associated with these types of vehicles is the weight and complexity of components required to combine the motive force of an electric motor with a standard internal combustion motor. The system of components needed to couple and decouple the two types of motor from the drive train adds substantially to the cost and weight of producing these types of vehicles. Increased weight reduces the efficiency of the vehicle and requires more fuel and electrical energy to compensate.

It is an object of the present invention to produce a propulsion system for a hybrid r

electric vehicle that at least mitigates some of these problems. Disclosure of the Invention

The invention provides in one aspect a propulsion system for a hybrid electric vehicle including:

- a flywheel; and

a shaft; and

an electric motor; and

a clutch; and

an electrical generator; and

- a combustion chamber; and

logic control means; and

electrical storage means,

wherein the flywheel is mounted on the shaft and spins at a substantially constant rotational velocity during operation of the vehicle. The electric motor is detachably coupled to one end of the shaft via the clutch, and the electrical generator is attached to the opposite end of the shaft. During start-up conditions for the vehicle, where the flywheel will have slowed down from its normal operational rotational velocity, or has completely stopped rotating, the electric motor is coupled to the shaft under the influence of the logic control means, and it is powered by either the vehicle's electrical storage means, or is coupled to an external power supply, and its torque is imposed upon the shaft, thereby causing the flywheel and electrical generator to rotationally accelerate up to their normal operating rotational velocity. When the flywheel has reached its substantially constant rotational velocity, the clutch decouples the electric motor from the shaft under the influence of the logic control means, and the electric motor is used to power the wheels of the vehicle when and as required. The torque of the flywheel continues to turn the electrical generator to generate electricity, which is then stored in the vehicle's electrical storage means. The combustion chamber is used to create a flow of exhaust gas that is directed to flow over the periphery of the fly wheel, whereat a portion of the kinetic energy of the exhaust gas flow is imparted into the flywheel in a turbine like arrangement, thereby replenishing the energy lost from the flywheel as its torque is used to drive the electrical generator. Preferably the substantially constant rotational speed of the flywheel is chosen to match the rotational speed of the electricity generator that matches its peak electrical efficiency relating to its ability to generate electricity. Preferably the propulsion system also includes:

a housing with a plurality of chambers; and

at least one cam; and

a cylinder; and

a piston; and

- a first exhaust port; and

a second exhaust port,

wherein the housing has a first chamber that encloses the flywheel, and a second chamber that encloses the cam, a third chamber that forms the cylinder in which the piston is constrained to move in a reciprocating motion under the influence of the cam, and a fourth chamber that defines the combustion chamber and is connected to the third chamber, wherein the fourth chamber has a plurality of injection ports and the first exhaust port, and the first exhaust port connects the combustion chamber to the first chamber. The interior of the first chamber includes channelling that guides the flow of the exhaust gas exiting the first exhaust port so that the flow is directed over the periphery of the flywheel. The shaft passes through the housing. The flywheel is a circular disc that is mounted on the shaft, and the flywheel is able to rotate wholly within the first chamber. The cam has a substantially circular disc portion, and at least a pair of diametrically opposed protuberances. The cam is also mounted upon the shaft, and the cam turns as the shaft turns, and as it turns, each protuberance in turn engages with the piston and drives the reciprocating action of the piston, relative to the cylinder, so that when in normal operation, the flow of the exhaust gas over the periphery of the flywheel causes a portion of the exhaust gas flow's kinetic energy to be transferred into the flywheel, thereby imparting a rotational force upon the flywheel, after which the flow of the exhaust gas is then directed to the second exhaust port whereat it exits the housing.

Preferably the periphery of the flywheel that interacts with the flow of exhaust gas includes a plurality of evenly spaced apart flutes that increase the interaction between the exhaust gas flow and the flywheel, thereby increasing the amount of kinetic energy that is transferred from the exhaust gas flow to the flywheel.

Preferably the piston is biased to rest at the bottom dead centre position relative to the cylinder unless it is under the influence of one of the protuberances on the cam.

Preferably the biasing means is a spring.

Preferably the plurality of injection ports include at least one fuel injection port, and at least one air injection port, and at least one water injection port.

Preferably temperature sensing means are included that measure the temperature in the combustion chamber, and feedback temperature data within the combustion chamber to the logic control means, and when the temperature is sensed to have reached a minimum set temperature, the logic control means are then used to control the injection of an appropriate amount of water into the combustion chamber.

Preferably the water is only injected into the combustion chamber when the temperature is sensed by the temperature sensing means to be sufficiently high enough to cause the liquid water to flash to steam inside the combustion chamber. The steam generated is used instead of combustion gas to flow from through the first exhaust port from the cylinder and transfer a portion of its kinetic energy into the flywheel. Preferably when the combustion chamber is in operation, the logic control means injects the water into the combustion chamber at discreet time intervals instead of fuel, thereby creating an alternating stream of combustion exhaust gas and a stream of steam to power the flywheel. Preferably the frequency and duration of the injection of the water into the combustion chamber is determined by the logic control means in order to keep the temperature inside the combustion chamber, and or the flywheel chamber, within a set temperature range, wherein if the temperature needs to be increased, combustion cycles occur exclusively, or more frequently, and alternatively, if the temperature needs to be decreased, water is injected exclusively, or more frequently.

Preferably each injection port is connected to an associated storage tank.

Preferably the fuel is either LPG or petrol.

Preferably each of the water, fuel and air are respectively fed into the combustion chamber as required, under the influence of the logic control means, under pressure.

Preferably when the vehicle is in operation, and under conditions where the electric motor is being driven by the wheels of the vehicle, for example when the vehicle is braking, or coasting downhill under the influence of gravity for example, the clutch is recoupled to the shaft under the influence of the logic control means, and the kinetic energy of the vehicle is then applied to the flywheel via the shaft to augment the energy imposed on it by the exhaust flow emanating from the combustion chamber.

Preferably the logic control means is able to completely cease with the injection of either the fuel and air, and/or the water, into the combustion chamber to conserve these resources when the operating conditions of the vehicle permits.

Preferably the electrical storage means includes a combination of batteries and capacitors. Preferably the logic control means determines where the electrical energy generated by the electrical generator is stored at any given time.

Preferred aspects of the invention will now be described with reference to the accompanying drawings. Brief Description of the Drawings

Figure 1 is a schematic representation of the present invention shown in the rear end view of a vehicle.

Figure 2 is a sectional view of the housing component of the invention that incorporates the flywheel, cam and combustion chambers.

Figures 3 and 4 show further detail of the operation of the cam inside the cam chamber of the housing.

Figures 5 and 6 show illustrations of recesses in the periphery of the flywheel to increase the transfer of kinetic energy from the flow of exhaust gas. Figure 7 shows further detail of the components in the present invention.

Detailed Description of the Preferred Embodiments

Referring to Figure 1 , we can see a schematic rear view of a vehicle 1. In the Figure we can see a shaft 3, a housing 5, an electric motor 7, an electrical generator 9, a clutch 11 that selectively couples the electric motor 7 to the shaft 3, and an electrical generator 9 that is coupled to the shaft 3. The housing 5 includes a combustion chamber 31 (not shown in this view, see Figure 2), and each of the water tank 15 and the fuel tank 17 and the air tank 19 are connected to the combustion chamber. Both the fuel tank 17 and air tank 19 are pressurised. A small pump 21 is used to feed the water to the combustion chamber 31 from the water tank 15. Control of the system is maintained by the logic control means 23.

Turning to Figure 2, we see a cut-away view of the housing 5. The shaft 3 passes through the housing 5. A flywheel 25 is located inside the first chamber 51. The flywheel 25 is attached to the shaft 3 and is able to spin wholly within the first chamber 51. The flywheel 25 includes a plurality of equally spaced apart recesses 37 around the periphery of the flywheel. Adjacent to the first chamber 51 is the second chamber 53. The cam 27 is housed wholly within the second chamber 53. A portion of the second chamber 53 includes the sump 35 that keeps the cam 27 lubricated. The cam 27 is fixed to the shaft 3. Above the second chamber is the third chamber 55. The third chamber 55 defines the cylinder in which the piston 29 is able to move in a reciprocating motion under the influence of the cam 27. The spring 49 biases the piston 29 to the bottom dead centre position when the piston 29 is not being influenced by the motion of the cam 27. The reciprocating action of the piston has direct effect on the combustion chamber 31. The combustion chamber 31 includes three separate injectors. The first is the fuel injector 43, the second is the air injector 45 and finally there is a water injector 41. The timing and amount of substance injected is controlled by the logic control means 23.

A temperature sensor 57 is used to measure the temperature inside the chamber, and the data from that sensor is fed back to the logic control means 23. The combustion chamber 31 is connected to the first chamber 51 by way of the first exhaust port 33. The opening and closing of the first exhaust port 33 is controlled by the position of the piston 29. When the piston 29 is in its rest position at bottom dead centre, the first exhaust 33 is open, and when the piston 29 is forced upwardly by the influence of the cam 27, the piston physically obstructs the port 33.

Combustion occurs within the combustion chamber 31 by the injection of an appropriate amount of fuel and air via their respective injector ports under the control of the logic control means 23. As the piston 29 is forced up towards the combustion chamber 31, the piston 29 closes the first exhaust port 33 and then pressurizes the fuel air mix inside the combustion chamber 31. This mix is then ignited by the ignition means 47, which is preferably a conventional spark plug.

After combustion, the piston moves back towards it bottom dead centre position, and this causes the piston to open the first exhaust port 33. The high pressure combustion gas is then able to pass through the first exhaust port and into the first chamber 51. The high velocity flow of the combustion gas is then directed to flow over the periphery of the flywheel 25. The plurality of recesses 37 in the periphery of the flywheel 25 interact with the flow of the combustion gas, thereby increasing the amount of kinetic energy exchanged between the flow of the gas and the flywheel 25. As subsequent combustion cycles occur, the temperature in the combustion chamber, and the housing will increase. This temperature is sensed by the temperature sensor 57. Temperature information from the temperature sensor 57 is fed back to the logic control means 23. When the temperature inside the combustion chamber 31 and the housing 5 is sensed to have reach a lower set limit, water is injected into the combustion chamber 31 when the piston is in its top dead centre position. The lower set limit is sufficiently high to ensure the water is flashed to steam, but not too high so as to affect the mechanical integrity of the individual components or the reciprocating action of the piston 29. The flashing of the water to steam inside the chamber removes heat from the system and maintains the temperature of the system within a lower and upper set temperature limit. The advantage is that apart from the pump 21 used to pressurise the flow of water into the chamber, there is no need for a radiator or fan(s) to cool the housing. The logic control means 23 is used to determine the appropriate time(s) during operation of the vehicle when water is injected into the combustion chamber 31. This may coincide with several consecutive reciprocating cycles of the piston 29 instead of combustion of fuel, or every alternate cycle, wherein there is a combustion cycle followed thereafter by a steam cycle, or in any other combination of cycles with a view to conserving fuel, minimising emissions and maintaining the temperature of the chamber and its surrounding housing within a set temperature range.

In another embodiment, the pump 21 can be removed completely from the system, and instead the water tank 15 may be pressurised by compressed air, preferably from the compressed air tank.

Turning to Figure 3 and 4, we are shown some more detail of the cam 27 and the second chamber 53. As shown, the cam 27 is fixed to the shaft 3. As the shaft rotates, so does the cam. A pair of diametrically opposed protrusions 59 extend from the periphery of the cam 27. As the cam 27 rotates, each protrusion 59 engages with the lower end of the piston 29, thereby forcing it upwardly within the third chamber 55, and against the bias of the spring 49. The motion of the cam 27 and its engagement with the lower end of the piston 29 is lubricated by the lubricant in the sump 35.

Figures 5 and 6 show some more detail of the equally spaced recesses 37 around the periphery of the flywheel 25. In an alternative embodiment as shown in Figure 6, the recesses are on the side of the flywheel 25 out near its circumference.

In Figure 7 we are shown further schematic details of the present invention, showing the housing assembly 5 with key components of the invention attached.

Description will now be made of the operation of the system under a variety of modes applicable to the use of the vehicle.

The system is for use in a hybrid electric vehicle. According to a preferred form of the invention, at least one of the wheel of the vehicle is driven by the operation of the electric motor. The electric motor draws its supply of electrical power normally from the electrical power supply means. Typically this is a bank of batteries and capacitors. The electric motor only powers the at least one wheel when the vehicle is under load.

The power consumed by the electric motor is replenished by the electrical generator. This ensure that the electrical supply means always has sufficient supply of electricity to power the electric motor while conditions persist to enable the system to operate.

It is well known that electrical generators have an rpm speed that is the best match to provide peak electrical energy generation efficiency. The object of the present invention is to ensure that the electrical generator is always turning at this peak rpm. This is facilitated by the inclusion of the flywheel. The flywheel is designed to always turn at the peak rpm speed that matches the electrical generator's peak efficiency.

There are a number of operational modes of the vehicle which affect the interaction of components in the system. These will now be described in greater detail 1. Vehicle Start-Up Mode

When the vehicle has not been in operation for a sufficient time, the spin of the flywheel will have slowed, or it will have completely stopped. When the vehicle is in this condition, the logic control means will then disengage the electric motor from the vehicle's wheels, and couple the electric motor to the shaft 3 via the clutch. The electric motor is then used to accelerate the flywheel up to its operational speed that matches the peak efficiency of the electrical generator. Once this speed is reached, the logic control means will then start the combustion process inside the combustion chamber, and disengage the electric motor from the shaft via the clutch.

The torque of the flywheel continues to turn the electrical generator after the electric motor has disengaged from the shaft. As the generator turns, and uses up torque, the torque is replenished by the interaction of the exhaust gas and/or steam created inside the combustion chamber that flows via the first exhaust port into the first chamber, and across the periphery of the flywheel. A portion of the kinetic energy of the gas and/or steam is transferred into the flywheel.

During this start-up mode of operation, the electric motor may be optionally connected to a source of external power.

2. Vehicle in Use Mode

In this mode, the electric motor is recoupled to the drive wheel(s) of the vehicle. All motive force, when required is provided to the drive wheel(s) from the electric motor. All electrical energy consumed by the operation of the electric motor is replenished by the electrical generator.

In circumstances where the momentum of the vehicle is able to drive the electric motor, for example when the vehicle is coasting down a hill, the logic control means is able to couple the vehicle's drive train to the shaft so that the vehicle's momentum is converted to rotational energy that is then fed back into the flywheel, and at the same time cease operation of the combustion chamber to generate gas in order to conserver the vehicle's fuel, air and water.

The temperature of the combustion chamber, and its surrounding housing and other associated components are kept within an acceptable range of temperatures by the controlled injection of water, via the logic control means, into the chamber. A temperature sensor is used to measure the temperature inside the chamber, and when it reaches the lower set limit, a controlled amount of water is injected into the combustion chamber wherein it flashes to steam. The resulting steam is then used instead of combustion gas to flow through the first exhaust port and into the first chamber wherein a portion of its kinetic energy is transferred to the flywheel. This conserves fuel and air, and also the flashing of the liquid water to steam exchanges heat out of the system, thereby controlling the temperature of the combustion chamber and its surrounding components.

The first chamber has a second exhaust port that enables either the combustion gas or the steam to flow out of the housing and into the exhaust system for the vehicle.

Whilst the above description includes the preferred embodiments of the invention, it is to be understood that many variations, alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the essential features or the spirit or ambit of the invention.

It will be also understood that where the word "comprise", and variations such as "comprises" and "comprising", are used in this specification, unless the context requires otherwise such use is intended to imply the inclusion of a stated feature or features but is not to be taken as excluding the presence of another feature or features.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge in Australia.