Brake Thermal Efficiency
The brake thermal efficiency ratio is defined as the
ratio of the output in the brake power to that of the
chemical energy input in the form of fuel supply. The
brake thermal efficiency gives an idea of output power
generated by the engine with respect to heat supplied in
the form of fuel. It is the true indication of the efficiency
with which the thermodynamic input is converted into
mechanical work.Figure 3 and figure 4 represent the effect of brake power
on the brake thermal efficiency for without EGR and
with EGR condition respectively for all fuel blends. It is
observed that, initially with increasing brake power, the
brake thermal efficiencies for each fuel (diesel,
diesel-biodiesel blends) increased due to reduction in
heat loss and increase in power developed with increase
in load. The maximum brake thermal efficiency was
obtained at around 5.0 to 5.5 kW and then tends to
decrease with further increase of load.