Читать книгу Internal Combustion Engines - Allan T. Kirkpatrick - Страница 49

1 From Table 2.1, the heat of combustion of octane = 44,300 kJ/kg, so the nondimensional energy addition isThe cycle average specific heats and are

2 The thermal efficiency isand the imep/ is

3 The maximum temperature and pressure are

Comment: The efficiency we have computed, , is about twice as large as measured for actual engines. There are a number of reasons for this. We have not accounted for internal friction, heat transfer losses, and the incomplete combustion of fuel within the engine cylinder.