Question: Problem 2 . A four - cylinder, 2 . 5 - liter, SI automobile engine operates at WOT on a four - stroke airstandard Otto

Problem 2. A four-cylinder, 2.5-liter, SI automobile engine operates at WOT on a four-stroke airstandard Otto cycle at 3000 RPM. The engine has a compression ratio of 8:1, a mechanical efficiency of 86%, and a stroke-to-bore ratio SB=1.025. Fuel is isooctane with AF=15, a heating value of 44,300kJkg, and combustion efficiency c=100%, At the start of the compression stroke, conditions in the cylinder combustion chamber are 100 kPa and 60C. It can be assumed that there is a 4% exhaust residual left over from the previous cycle. The engine is converted to operate on an air-standard Miller cycle with early valve closing (cycle 6-7-1-7-2-3-4-5-6 in Fig. 16). It has a compression ratio of 8:1 and an expansion ratio of 10:1. A supercharger is added that gives a cylinder pressure of 160 kPa when the intake valve closes, as shown in the figure below. The temperature is again 60C at this point. The same fuel and AF are used with combustion efficiency.
Calculate:
temperature and pressure at all points in the cycle
indicated thermal efficiency
indicated mean effective pressure
exhaust temperature
Problem 2 . A four - cylinder, 2 . 5 - liter, SI

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