The Use of Availability and Energy Balances in Diesel Engines

In this study the application of an availability balance and two alternative forms of energy balance to two experimental single-cylinder engines, a water-cooled and an uncooled diesel, are described. Both the first-law efficiency and the second-law efficiency of the uncooled engine were significantly higher than those of the water-cooled engine for equal BMEP levels. The loss of availability due to irreversibilities accounted for as much as 50% of the input fuel availability at light loads. Based on an energy balance, the heat loss from the uncooled engine was found to range from 50 to 70% of the corresponding heat loss from the water-cooled engine.