OPOC TWO-STROKE ENGINETopic Seminar Presented by: Ashok Kumar . Y. G 4PS06AU003 Under the Guidance of: Mr.K.B.Sidde Gowda Associate Professor Dept. Of Automobile Engg.
Introduction Engine : Device that transforms one form of energy to another form.Heat engine:Classification based on combustion process Internal Combustion Engine External Combustion EngineClassification based on mechanism Reciprocating Engine Rotary Engine
Reciprocating engine Classification based on arrangement ofcylinders• Inline Engine• V Engine• Radial Engine• Delta Engine• X Engine• H Engine• U Engine
Two-Stroke engines:The two stroke engines is the one in which,one revolution of crank shaft completes allthe processes(suction, compression,ignition, expansion and exhaust).The main drawbacks of the two-strokeengine are lake of efficiency and escapingof un-burnt fuel.
OPOC Two-Stroke engine: Developed by: EcoMotors International, a startup based in Troy, Michigan. According to the company the two-stroke engine is up to 50 percent more efficient than most vehicle engines and pollutes far less than a conventional two-stroke engine.
The engine uses two piston movements per cycle(w.r.t. four-stroke engine), instead of four, and each cylinder contains two opposing pistons, instead of one. A single crankshaft sits in between pairs of cylinders. The design relies on precise computerized control of all the components.
When the outer piston moves away from center of the cylinder the inner piston moves in opposite direction, resulting in opening of intake manifold. The fresh air enters into the cylinder. Then the pistons travel near the center of the cylinder compressing the air.
The temperature of air increases. At that time fuel will be injected and the combustion takes place. When Expansion takes place exhaust manifold will be opened before the intake manifold opens and then the burnt gas will starts to escape. Addition to that, when inlet manifold opens, scavenging process takes place.
Technologies which have helped to reduce theemissions of the OPOC two-stroke engine: An electric turbocharger allows for "variable compression ratio," whereby the inlet pressure fed into the engines cylinders is varied to maximize efficiency. An approach called asymmetrical port timing- -opening the intake and exhaust ports at different times--helps improve the efficiency of gas exchange.
High pressure injection and computerized control of injection improve the overall efficiency of the cycle.
The development in clutch technology enables customers to take advantage of the engine’s modular displacement capability. The clutch assembly is housed between two engine modules, and is engaged when vehicle power demands require both modules to deliver power.
When the power of the second module is not needed, the clutch is disengaged, allowing the second engine to stop completely. This not only improves fuel economy by reducing parasitic losses, but also improves the efficiency of the primary module.
Figure of two module OPOC with the electricallycontrolled clutch:
Advantages: Putting two pistons inside each cylinder also means that each piston only travels half as far as it normally would in a two-stroke engine, allowing the engine to run faster. Delivers twice as many power strokes per revolution Requires few parts compared 4-stroke engine.
These factors, account for a 15 percent efficiency improvement. Having half as many parts as a conventional engine (the OPOC does not have cylinder head or valve-train components, and it has fewer bearings) helps to reduce friction and heat loss.
Multiple engines, or "modules," can be used together to boost the fuel efficiency of a vehicle by as much as 45 percent. In addition to the efficiency gains of the engine itself, extra modules can be deactivated when they arent needed using electrically controlled clutch. This also increases the fuel efficiency upto 50%.
Advantages:The engine advantages engine offers: High power-to-weight ratio High power-to-volume ratio Use of a variety of fuels including gasoline, diesel, natural gas, JP8 and hydrogen Assisted HCCI combustion using proprietary diesel fuel system Conventional parts, materials and maintenance
Difference between common and OPOC two strokeengines:Sl.no common OPOC1. Piston moves till the TDC. Piston moves only till the center of the cylinder.2. Only one piston inside the cylinder. Two pistons inside the cylinder.3. Less efficient. More efficient.4. Sensors are not required. Sensors are required and important.5. Electrical clutch is absent. Electrical clutch is present.6. One cylinder on the side of the Consists of two cylinders on either crankshaft. side of a crankshaft.