The present invention generally relates to a rotary internal combustion engine, and more particularly to a Wankel rotary engine. Further, the present invention relates to a method of fuel-air injection to the above rotary internal combustion engine and Wankel engine comprising the same.
Wankel rotary engine delivers advantages of simplicity, smoothness, compactness, high revolutions per minute, and a high power-to-weight ratio. However, with a unique structure it also has many disadvantages such as apex wear out, slow combustion due to narrow-shaped combustion chamber, poor fuel economy and high emissions.
Fuel-Air Injection Rotary (refer to as FAIR) engine is a structure advancement over conventional Wankel engine. It replaces the air compression mechanism of a Wankel engine with a secondary combustion mechanism in addition to the existing one, so a FAIR engine operates with two combustion cycles and delivers two power strokes per shaft revolution versus a Wankel engine which operates with one combustion cycle and delivers one power stroke per shaft revolution.
Combustion of FAIR engine depends on fuel and air injections. FAIR engine implements Oxygen Enriched Compressed Air (OECA) injection to accelerate the chemical reaction for thorough combustion and emission reduction. Fuel is injected before the air injection and spark plug ignites the mixture, the combustion depends on air injection and independent to fuel property; various fuel types can be used.
What follows is a description of principles of operation,
The inner gear of the rotor has a 3:1 ratio to the stationary gear, a 180° rotation of the shaft is in synchronizing with a 60° rotation of the rotor and associated chambers. Table 1 represents status change of chambers at active positions. Column 1 indicates the position where chambers change state. Column 2 indicates figures in relation to column 1 positions. Column 3, 4, 5 describe thermal status of chambers.
Oil and fuel injections are also known as maintenance cycles, the injected oil lubricates the apexes and injected fuel brings down the temperature of apexes and rotor tips. Fuel can be in liquid or gas phase such as alcohol, gasoline, diesel, methane or propane. FAIR engine may use local produced fuel for better fuel economy, fuel sources could be switched manually or automatically during engine operation time depending on fuel tank sensor status. The controller computer (computer) holds a look up table in controlling the amount of injected fuel and air mixture to match the stoichiometric ratio and power output.
In regards to air injections, rotary engine in general has narrow shaped chamber which causes slow combustion and emission problems. FAIR engine implements Oxygen Enriched Compressed Air (OECA) injection to accelerate the chemical reaction of fuel combustion, the injected OECA not only enhancing combustion, but also reducing harmful mono-nitrogen oxide (NOx) emission and increasing the carried oxygen density within the air tank.
When pressure sensor detects pressure low of the OECA tank, the computer 810 may connect the clutch to generate OECA and filling up the tank. Else, when computer receives power demand, the software has the option to disconnect the clutch and offload the air compressor subsystem to increase the net output power as long as the pressure in OECA tank remains. With sealable air intake and “U” shape exhaust pipe, FAIR engine may be operated under water with stored OECA, the stored OECA also may be used for life support.
To start the engine, the computer disconnects the clutch and disable fuel injectors 809, the air injection pushes the rotor to one of the injection group position, then the normal combustion procedures start the engine with fuel-air injection and ignition.
The foregoing discussion discloses and describes merely exemplary methods and implementations. As will be understood by those familiar with the art, the disclosed subject matter may be embodied in other specific forms without departing from the spirit or characteristics thereof. Accordingly, the present disclosure is intended to be illustrative, but not limiting, of the scope, which is set forth in the following claims.