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Four-stroke cycle used in gasoline/petrol engines: intake (1), compression (2), power (3), and exhaust (4). The right blue side is the intake port and the left brown side is the exhaust port. The cylinder wall is a thin sleeve surrounding the piston head which creates a space for the combustion of fuel and the genesis of mechanical energy.
Four-stroking is a condition of two-stroke engines where combustion occurs every four strokes or more, rather than every two. Though normal in some instances at idle, extremely high engine speeds, and when letting off the throttle, such firing is uneven, noisy and may, in cases of malfunction, damage the engine if allowed to continue unabated.
The first person to build a working four-stroke engine, a stationary engine using a coal gas-air mixture for fuel (a gas engine), was German engineer Nicolaus Otto. [4] This is why the four-stroke principle today is commonly known as the Otto cycle and four-stroke engines using spark plugs often are called Otto engines.
The two-cycle modes are currently being researched at Ricardo Consulting Engineers in the UK. The concept consists in switching from one mode to the other depending on the rpm value. The four-stroke engine is more efficient when running at full throttle, while the opposite is the case for the two-stroke engine.
The induction stroke is the first phase in a four-stroke (e.g. Otto cycle or Diesel cycle) engine.It involves the downward movement of the piston, creating a partial vacuum that draws an air-fuel mixture (or air alone, in the case of a direct injection engine) into the combustion chamber.
Two-Stroke engine showing ports in the cylinder walls. The timing cannot be varied. Many two-stroke cycle and all wankel engines do not have a camshaft or valves, and the port timing can only be varied by machining the ports , and/or modifying the piston skirt (two-stroke applications).
#Power stroke - Fuel combusts and piston is pushed downwards. #Exhaust stroke - Exhaust is driven out. This is a large improvement on the existing image; it is higher resolution, has smoother animation and removes some of the unnecessary detail. Articles this image appears in None as yet, but will be on: Engine; Internal combustion engine ...
A four-stroke straight-four engine always has a cylinder on its power stroke, unlike engines with fewer cylinders where there is no power stroke occurring at certain times. Compared with a V4 engine or a flat-four engine, a straight-four engine only has one cylinder head, which reduces complexity and production cost.