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An engine is described as oversquare or short-stroke if its cylinders have a greater bore diameter than its stroke length, giving a bore/stroke ratio greater than 1:1. An oversquare engine allows for more and larger valves in the head of the cylinder, higher possible rpm by lowering maximum piston speed, and lower crank stress due to the lower ...
Consumption map of a 1.5-litre three-cylinder diesel engineA consumption map or efficiency map [1] is a chart that displays the brake-specific fuel consumption of an internal combustion engine at a given rotational speed and mean effective pressure, in grams per kilowatt-hour (g/kWh).
The stroke ratio, determined by dividing the bore by the stroke, traditionally indicated whether an engine was designed for power at high engine speeds or torque at lower engine speeds. [ 2 ] [ 3 ] The term "bore" can also be applied to the bore of a locomotive cylinder or steam engine pistons .
It is commonly used as an expression of an engine's size, and by extension as an indicator of the power (through mean effective pressure and rotational speed) an engine might be capable of producing and the amount of fuel it should be expected to consume. For this reason displacement is one of the measures often used in advertising, as well as ...
It is the ratio between the volume of the cylinder, when the piston is at the bottom of its stroke, and the volume when the piston is at the top of its stroke. The bore/stroke ratio is the ratio of the diameter of the piston, or "bore", to the length of travel within the cylinder, or "stroke". If this is around 1 the engine is said to be "square".
For example, motorcycle racing engines can use compression ratios as high as 14.7:1, and it is common to find motorcycles with compression ratios above 12.0:1 designed for 95 or higher octane fuel. Ethanol and methanol can take significantly higher compression ratios than gasoline.
The amount of power generated by a piston engine is related to its size (cylinder volume), whether it is a two-stroke engine or four-stroke design, volumetric efficiency, losses, air-to-fuel ratio, the calorific value of the fuel, oxygen content of the air and speed . The speed is ultimately limited by material strength and lubrication.
The Japanese version, which has a higher compression ratio, is capable of 247 bhp (184 kW; 250 PS) at 8,600 rpm. Honda's F20C Engine won a spot on Wards ' 10 Best Engines List twice, in 2000 and 2001.