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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 thermal efficiency of a theoretical cycle cannot exceed that of the Carnot cycle, whose efficiency is determined by the difference between the lower and upper operating temperatures of the engine. The upper operating temperature of an engine is limited by two main factors; the thermal operating limits of the materials, and the auto-ignition ...
Because pressure and temperature are strongly linked, knock can also be attenuated by controlling peak combustion chamber temperatures by compression ratio reduction, exhaust gas recirculation, appropriate calibration of the engine's ignition timing schedule, and careful design of the engine's combustion chambers and cooling system as well as ...
Engines must be designed so that ignition conditions occur at the desired timing. To achieve dynamic operation, the control system must manage the conditions that induce combustion. Options include the compression ratio, inducted gas temperature, inducted gas pressure, fuel-air ratio, or quantity of retained or re-inducted exhaust.
The Stirling engine has the highest theoretical efficiency of any thermal engine but it has a low output power to weight ratio, therefore Stirling engines of practical output tend to be large. The size effect of the Stirling engine is due to its reliance on the expansion of a gas with an increase in temperature and practical limits on the ...
The computer adjusted spark timing based on manifold vacuum, engine speed, engine temperature, throttle position over time, and incoming air temperature. Engines equipped with ELB used fixed-timing distributors without the traditional vacuum and centrifugal timing advance mechanisms.
A cold start can be difficult for an engine due to higher viscosity of oil and fuel in cold temperatures. Generally speaking, diesel engines have more difficulty starting at low outside temperatures than gasoline engines, and electric engines have the most problems. Diesel engines do not use spark plugs to ignite the air fuel mixture and rely ...
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.