Patent Application
20120240578
1. Field of the Invention
The present invention relates to internal combustion engines and more particularly to a hot charge engine with steam assist that can be used in a dual drive mode.
2. Description of the Prior Art
Since Otto made his first four stroke cycle engine, numerous engineers and scientists have spent countless hours trying to make a better engine. The modern automobile engine is better, but not much. More than 70% of the energy available from fuel combustion is wasted. Adding a little to the price, manufacturers could make more fuel efficient car engines. In the past, buyers cared more about looks, gadgets, pickup, and monthly payments than about efficiency. However that is changing in the modern world. There is tremendous growing concern about greenhouse gas emissions, and it is becoming much more expensive and dangerous to find oil. The recent BP spill in the Gulf of Mexico will cost the company billions of dollars and goes to show the dangers of going deeper and drilling in deeper water for oil. In addition, gas rationing may not be far away (some countries now have it).
There have been numerous reported attempts to make internal combustion engines more efficient including the injection of steam into the cylinders.
The compression stroke of a typical four stroke cycle internal combustion engine is designed to give adequate heat to the fuel for ignition, as well as to provide closer contact between oxygen and fuel molecules. Power is extracted from the engine output to perform the compression stroke. This power is mostly returned to the engine on the next stroke. Even without fuel, the next stroke would still be a power stroke due to compression. With fuel, the following stroke (power stroke) adds the pressure due to the combustion to the compression pressure and drives the engine. The above mentioned closer contact of the molecules results in more rapid combustion which, in most engines, needs to be modulated by fuel additives to prevent a condition called knock. Recycling a few cubic centimeters of exhaust gas to the intake stroke makes fuel burn more slowly reducing knock.
The standard gasoline engine has two downward strokes, with only one of them taking energy from the fuel to provide work. It would be extremely advantageous to have an internal combustion engine with two true power strokes per cycle.
A current trend is to compress, and sometimes cool, the air before intake in order to provide more oxygen into the displaced volume thus allowing more fuel to be burned per unit displacement. Such an engine requires more displacement. However, displacement increase, by larger cylinders or stroke length, means additional engine metal. A turbocharger also requires more metal and hence more weight. It would be extremely advantageous to eliminate the radiator and water cooling system if possible since this lowers weight and manufacturing cost.
Almost all present vehicles have only one engine. This engine normally drives either the rear or front wheels. Four wheel drive transmissions can couple drive from a single engine to all four wheels on some vehicles. It would be advantageous to have a duel drive engine where some of the cylinders drive the front wheels and other cylinders drive the rear wheels, so that one engine could be stopped when not needed.
The present invention relates to a steam assisted, optional dual drive internal combustion engine with cylinders containing a piston where the region above a piston is a combustion chamber and a region below a piston is a water injection chamber. The engine generally has a single intake/exhaust valve in the combustion chamber, and an exhaust valve in said water injection chamber. A water injector in the water injection chamber injects water during a compression stroke of the piston which immediately vaporizes to become steam providing an upward second power stroke. The amount of water injected can be determined by the chamber temperature. The engine can have an EGR chamber with a regulator to admit a measured exhaust gas recirculation into the combustion chamber on the intake stroke, and it can utilize intake-exhaust heat exchange to pre-heat the intake mixture. In an alternate embodiment, the engine can use different cylinders to separately drive the front and rear wheels of a vehicle so that one engine can be shut off when not needed.
Attention is now drawn to several drawings that illustrate features of the present invention.
Several drawings and illustrations have been presented to aid in understanding the present invention. The scope of the present invention is not limited to what is shown in the figures.
The present invention relates to an internal combustion engine that uses steam-assist to achieve two true power strokes per cycle. It also relates to an embodiment where different cylinders drive different wheels on a vehicle.
In this two-power-stroke engine, steam drives the compression stroke so that the four stroke cycle engine has two power strokes. This is accomplished by use of a double acting cylinder design. Also, hot air entering on the inlet stroke reduces the compression ratio required for best fuel ignition. The weight of water storage used to drive the compression stroke is offset by lower fuel storage weight needed for the power stroke.
Beginning with the inlet stroke, when the piston is near top dead center, valves 8 and 11 both open. As the piston moves down it lowers the pressure in the combustion chamber 1 and the EGR chamber 3. Since the pressure is higher in the heated air inlet chamber 5 than in the EGR chamber 3, a check valve 7 opens allowing air intake to combustion the chamber 1. Lower pressure in EGR chamber 3 than in the exhaust chamber 6 closes a check valve 10. When the entrained volume of gas from the EGR chamber 3 has entered the combustion chamber 1, an injector 12 opens to admit the desired quantity of fuel into combustion chamber 1. The piston moves to near bottom dead center filling the combustion chamber 1 with the measured fuel-air mixture and forcing out to exhaust the content of the doubly-acting chamber 2. Valves 8 and 11 then close.
As the piston begins the compression stroke, a measured quantity of water is injected into chamber 2 from a water injector 13. Heat from the piston and cylinder liner immediately cause this water to boil yielding steam pressure. This steam pressure in the doubly-acting chamber 2 beneath the piston 17 acts to move the piston upward compressing the fuel-air mixture in chamber 1 while cooling the piston and cylinder surfaces. The air-fuel mixture is then ignited in the normal way by a spark plug or igniter 25. The amount of exhaust gas recycling needed for prevention excessive nitrogen oxides can be controlled by movement of a diaphragm or piston actuated by a control 24 which changes the volume of the EGR chamber 3. Because the respective chambers are at low pressure, high pressures are not necessary for fuel and water injection.
Unlike carburetion, fuel that is injected directly into a cylinder results in a richer mix when the accelerator pedal is depressed to increase power. Cool air can be injected from a cool air chamber 4 through cool air inlet valve 14 and a check valve 9 at the time of gas-pedal depression, increasing oxygen intake to lean the mixture and avoid unburned fuel. Piston ring 19 lubrication can be supplied by a passageway in the piston rod, or a fuel-oil mix can be used.
Several advantages are apparent from the present invention:
1—Lower cylinder head poppet valve temperature
2—No lateral pressure between piston and cylinder* Conventional 4 stroke cycle engines use a lengthened piston to act as a crosshead-slipper guide. The shorter the connecting rod, the greater lateral force vector acts between piston and cylinder resulting in friction drag and cylinder and ring wear.
3—Additional power stroke gives more mpg
4—Radiator and water cooling not needed
In an alternate embodiment of the present invention, some of the cylinders can supply power to a vehicle's rear wheels while other cylinders supply power to its front wheels. Since full power is only needed for acceleration and climbing, if half of the cylinders of an automobile engine are connected to the front wheels, and the other half are connected to the back wheels, a clutch could eliminate one half while the other half drives the car. This particular embodiment can apply to any engine, not just a steam-assisted engine. It can also be split into two separate engines or a connected, split engine containing, a rear engine and a front engine. This requires a little more engine weight, but the front engine and the back engine does away with the drive shaft and related couplings and improves overall traction and balance. Exhaust gas, or cooling water, from the running engine could keep the stopped engine warm. Only the master engine needs a flywheel and transmission system.
Operation of the dual-engine vehicle shown in
Several descriptions and illustrations have been presented to aid in understanding the features of the present invention. One with skill in the art will recognize that numerous changes and variations can be made without departing from the spirit of the invention. Each of these changes and variations is within the scope of the present invention.
