Experiments on the effect of engine speed, load, equivalence ratio, spark timing and coolant temperature on the energy balance of a turbocharged hydrogen engine

Abstract

Internal combustion engines are used to translate the chemical energy of fuel to the brake power and over two-third of energy is wasted in the form of exergy and anergy in this process. An experimental energy balance analysis can make the engine energy flow clear and help to recycle the exergy of exhaust gas to increase brake thermal efficiency. In this paper, the effect of five different parameters on the energy distribution was investigated using heat balance test data from a 2.3 L turbocharged hydrogen engine. The results show that when proportion of exhaust gas energy ranges from 24.1% to 36.4% with various engine speeds, brake thermal efficiency can increase 3.69% at 2000 rpm and 7.67% at 4000 rpm with various load, which means that high engine speed and load are beneficial to increase exergy of total system. Both Engine speed and brake thermal efficiency increase with equivalence ratio ranging from 0.4 to 0.9, while proportion of energy of cooling system decreases, which means that both power and economic ascend with increasing equivalence ratio and anergy of total system decreases at low engine speed and load. Furthermore, proportion of exhaust gas energy can increase by 3% at 75% load and 2.5% at 50% load with spark timing closing to TDC and NOx emission is decreasing. Finally, the variation of the coolant temperature has an almost negligible effect in terms of brake thermal efficiency but it can decrease anergy of total system.