The variation between brake thermal efficiency and brake power for diesel and producer gas on dual fuel operation is
illustrated in Fig. 2. A considerable reduction in brake thermal efficiency is observed in dual fuel mode as compared to that
of DF mode at all loads. The maximum efficiency achieved by Diesel was 27.5% whereas in dual fuel mode, maximumefficiency achieved was 26%, 25% and 24.5% for D+PG4lpm, D+PG6lpm and D+PG8lpm respectively. The reduction in
BTE is due to the lower calorific value of producer gas, which contains more combusted mixture that enters into the engine.
Producer gas evolved from the engine is at higher temperature and therefore density of producer gas is reduced, which in
turn reduces the mass flow rate of producer gas and air required for combustion, resulting in lowering the oxygen level
required for combustion. This insufficient oxygen in the combustion chamber is the cause of incomplete combustion [14].