Page 205 - Handbook of Energy Engineering Calculations

3. Compute the displacement
3
The displacement per cylinder d, in of any reciprocating internal-combustion
2
engine is d = L A where L = piston stroke, in; A = piston head area, in . For
i
i
i i
3
2
3
this engine, d = (18)(12) (π/4) = 2035 in (33.348 cm ) per cylinder.
e
The total displacement of this eight-cylinder engine is therefore (8
3
3
3
cylinders) (2035 in per cylinder) = 16,280 in (266,781 cm ).
4. Compute the compression ratio
For a reciprocating internal-combustion engine, the compression ratio r =
c
V /V , where V = cylinder volume at the start of the compression stroke, in 3
a
b
b
3
or ft ; V = combustion-space volume at the end of the compression stroke,
a
3
3
in or ft . When this relation is used, both volumes must be expressed in the
same units.
3
3
3
In this engine, V = 2035 in (33,348 cm ); V = (0.09)(2035) = 183.15 in .
a
b
Then r = 2035/183.15 = 11.1:1.
c
Related Calculations. Use these procedures for any reciprocating internal-
combustion engine, regardless of the fuel burned.

COOLING-WATER ENERGY NEEDS OF I-C ENGINES

A 1000-hbp (746-kW) diesel engine has a specific fuel consumption of 0.360
lb/(bhp · h) (0.22 kg/kWh). Determine the cooling-water flow required if the
higher heating value of the fuel is 10,350 Btu/lb (24,074 kJ/kg). The net heat

rejection rates of various parts of the engine are, in percent: jacket water,
11.5; turbocharger, 2.0; lube oil. 3.8; aftercooling, 4.0; exhaust, 34.7;
2
radiation, 7.5. How much 30-lb/in (abs) (206.8-kPa) steam can be generated
by the exhaust gas if this is a four-cycle engine? The engine operates at sea
level.

Calculation Procedure:

1. Compute the engine heat balance