07-03-2011, 11:22 AM
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IC Engine
The internal combustion engine is an engine in which the combustion, or rapid oxidation, of gas and air occurs in a confined space called a combustion chamber. This exothermic reaction of a fuel with an oxidizer creates gases of high temperature and pressure, which are permitted to expand. The defining feature of an internal combustion engine is that useful work is performed by the expanding hot gases acting directly to cause pressure, further causing movement of the piston inside the cylinder, for example by acting on pistons, rotors, or even by pressing on and moving the entire engine itself.This contrasts with external combustion engines, such as steam engines and Stirling engines, which use an external combustion chamber to heat a separate working fluid, which then in turn does work, for example by moving a piston.The term Internal Combustion Engine (ICE) is almost always used to refer specifically to reciprocating engines, Wankel engines and similar designs in which combustion is intermittent. However, continuous combustion engines, such as jet engines, most rockets and many gas turbines are also internal combustion engines
Two Stroke Engine
Four-stroke engine
The four strokes refer to intake, compression, combustion and exhaust strokes that occur during two crankshaft rotations per working cycle of Otto Cycle and Diesel engines.
The cycle begins at top dead center (TDC), when the piston is furthest away from the crankshaft. On the first stroke (intake/induction) of the piston, as the piston descends it reduces the pressure in the cylinder, a mixture of fuel and air is forced, by at least atmospheric pressure, into the cylinder through the intake (inlet) port. The intake (inlet) valve (or valves) then close(s) and the following stroke (compression) compresses the fuel-air mixture.
The air-fuel mixture is then ignited, usually by a spark plug for a gasoline or Otto cycle engine or by the heat and pressure of compression for a Diesel cycle or compression ignition engine, at approximately the top of the compression stroke. The resulting expansion of burning gases pushes the piston downward for the third stroke (power) and in the fourth stroke (exhaust) the piston pushes the products of combustion from the cylinder through an exhaust valve or valves.
6 STROKE ENGINE
Six-stroke IC Engine:
The six stroke engine captures the wasted heat from the 4 stroke Otto cycle and creates steam which simultaneously cools the engine while providing a free power stroke. This removes the need for a cooling system making the engine lighter plus giving 40% increased efficiency over the Otto Cycle.Head Technology combines a four stroke engine bottom end with a ported cylinder which closely resembles that of a two stroke, thus 4+2= Six Stroke. It has an opposing piston which acts in unison with auxiliary low pressure reed and rotary valves, allowing variable compression and a range of tuning options
As well as extracting power, the additional stroke cools the engine and removes the need for a cooling system making the engine lighter and giving 40% increased efficiency over the Otto Cycle. The pistons in a six stroke engine go up and down six times for each injection of fuel.
Advantages of 6 Stroke Engine:
1.Reduction in fuel consumption
2.Dramatic reduction in pollution
3.Better scavenging and more extraction of work per cycle
4.Lower engine temperature - so , easy to maintain the optimum engine 5.temperature level for better performance
6.Less friction – so , less wear and tear
7.The six-stroke engine does not require any basic modification to the existing engines. All technological experience and production methods remain unaltered.
CURRENTLY NOTABLE 6 STROKE ENGINE’S
The currently notable six stroke engine designs include Crower's six stroke engine, the Bajulaz engine and the Six-stroke engine (Trivandrum).
1) Bajulaz six stroke engine
The Bajulaz six stroke engine is similar to a regular combustion engine in design. There are however modifications to the cylinder head, with two supplementary fixed capacity chambers , a combustion chamber and an air preheating chamber above each cylinder. The combustion chamber receives a charge of heated air from the cylinder and the injection of fuel begins an isochoric burn which has increased thermal efficiency compared to a burn in the cylinder. The high pressure achieved is then released into the cylinder to work the power stroke. Meanwhile a second chamber which blankets the combustion chamber has had its air contents heated to a high degree by heat passing through the walls from the burn. This heated and pressurized air is then used to power another stroke of the piston in the cylinder. The advantages of the engine include reduction in fuel consumption by at least 40%, two expansion strokes (work) in six strokes, multi-fuel usage capability, and a dramatic reduction in pollution.
Bajulaz Six Stroke Engine was invented in 1989 by the Bajulaz S A ,company of Geneva, Switzerland and has U.S. Patent 4,809,511 and U.S. Patent 4,513,568 . The Bajulaz six stroke engine features are:
1.Reduction in fuel consumption by at least 40%
2.Two expansions (work) in six strokes
3.Multifuel
4.Dramatic reduction in pollution
5.Liquefied Petroleum Gas
6.Costs comparable to those of a four-stroke engine
