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In an external combustion engine, such as a steam engine, the control of the valve timing is by the valve gear. In a typical piston valve arrangement, the timing of the intake and exhaust events for each cylinder are inextricably related as they are governed by the movement of a single piston uncovering two ports. However, the duration of the ...
This entails controlling the admission and exhaust of steam to and from the cylinders with a valve linked to the motion of the piston. [3] For timing and dimensioning of slide or piston valves where the valve opens and closes the steam and exhaust ports, a consideration of the "lap" and "lead" is required.
Variable valve timing (VVT) is the process of altering the timing of a valve lift event in an internal combustion engine, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combination with variable valve lift systems.
For this inline-4 engine, 1-3-4-2 could be a valid firing order.. The firing order of an internal combustion engine is the sequence of ignition for the cylinders.. In a spark ignition (e.g. gasoline/petrol) engine, the firing order corresponds to the order in which the spark plugs are operated.
The valve gear, actuated by connection to the driving wheels, ensures that steam is delivered to the piston with precision. Types are slide valves, piston valves or poppet valves. [2] [3]: 62 Valve chest / Steam chest Valve chamber next to the cylinder (24) containing passageways to distribute steam to the cylinders. [6]: 41 [3]: 75 Firebox
The Alfa Romeo Twin Spark engine, introduced in the 1987 Alfa Romeo 75, also uses variable valve timing. [3] [4] The Alfa system varies the phase (not the duration) of the cam timing and operates on the inlet camshaft. [5] Alfa Romeo's variator is a cylindrical chamber that contains a pressure chamber and piston along with helical splines.
Pressure in cylinder pattern in dependence on ignition timing: (a) - misfire, (b) too soon, (c) optimal, (d) too late. In a spark ignition internal combustion engine, ignition timing is the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke.
The crankshaft configuration varies amongst opposed-engine designs. One layout has a flat/boxer engine at its center and adds an additional opposed-piston to each end so there are two pistons per cylinder on each side. An X engine is essentially two V engines joined by a common crankshaft. A majority of these were existing V-12 engines ...