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Rolls-Royce Avon early jet engine showing 1 of 2 sets of 3 valves at the top and 1 of 2 valves at the bottom which release some air from the compressor, pressure ratio 7.45:1, for starting and low speed running. Also visible at the front is the row of bearings for the variable inlet guide vanes.
Performance tuning of an engine can involve revising some of the design decisions taken during the development of the engine. Setting the idle speed, air-fuel ratio, carburetor balance, spark plug and distributor point gaps, and ignition timing were regular maintenance tasks for older engines and are the final but essential steps in setting up ...
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.
Specific thrust is the thrust per unit air mass flowrate of a jet engine (e.g. turbojet, turbofan, etc.) and can be calculated by the ratio of net thrust/total intake airflow. [1] Low specific thrust engines tend to be more efficient of propellant (at subsonic speeds), but also have a lower effective exhaust velocity and lower maximum airspeed.
With the help of geometrically variable turbo-charging system (albeit more maintenance) this also increases the engines' torque at low engine speeds (1,200–1,800 rpm). Low speed diesel engines like the MAN S80ME-C7 have achieved an overall energy conversion efficiency of 54.4%, which is the highest conversion of fuel into power by any single ...
The propeller speed reduction unit of a Rolls-Royce R engine. A propeller speed reduction unit is a gearbox or a belt and pulley device used to reduce the output revolutions per minute (rpm) from the higher input rpm of the powerplant. [1]
Overspeed is a condition in which an engine is allowed or forced to turn beyond its design limit. The consequences of running an engine too fast vary by engine type and model and depend upon several factors, the most important of which are the duration of the overspeed and the speed attained.
A high compression ratio is used in the auxiliary combustion chamber. A moderate compression ratio is used in the main combustion chamber wherein a homogeneous air-fuel mixture is compressed / heated near, yet below, the auto-ignition threshold.