Page 236 - Handbook of Energy Engineering Calculations

Related Calculations. Use the general data presented here for selecting
internal-combustion engines having ratings up to 200 hp (150 kW). For larger
engines, other factors such as weight, specific fuel consumption, lube-oil

consumption, etc., become important considerations. The method given here
is the work of Paul F. Jacobi, as reported in Product Engineering.

DIESEL-ENGINE VOLUMETRIC EFFICIENCY

A four-cycle six-cylinder diesel engine of 4.25-in (11.4-cm) bore and 60-in
(15.2-cm) stroke running at 1200 rpm has 9 percent CO present in the
2
exhaust gas. The fuel consumption is 28 lb (12.7 kg) per hour. Assuming that
13.7 percent CO indicates an air-fuel ratio of 15 lb of air to 1 lb (6.6 kg to
2
0.45 kg), calculate the volumetric efficiency of the engine. Intake air
temperature is 60°F (15.6°C) and the barometric pressure is 29.8 in (79.7
cm).

Calculation Procedure:

1. Find the percentage of N in the exhaust gas
2
Atmospheric air contains 76.9 percent nitrogen by weight. If an analysis of
the fuel oil shows zero nitrogen before combustion, all the nitrogen in the
exhaust gas must come from the air. Therefore, with 13.7 percent CO by
2