The Effect of Compression Ratio on Performance of Generator Set Fuelled with Raw Biogas

In order to utilize a raw biogas as a fuel of generator set (gen-set), it is important to figure out optimum operating parameter of the gen-set, i.e. compression ratio. The present work aims to investigate the effect of compression ratio on performance of 3 kW gen-set fuelled with raw biogas and to obtain optimum compression ratio for operation of the gen-set on raw biogas. The gen-set used in the present work is bi-fuel engine, i.e. fuelled with gasoline or LPG. The performance of the engine fuelled with raw biogas in terms of brake power, brake torque, brake specific fuel consumption, and thermal efficiency is evaluated at compression ratio of 7.5, 8.5, 9.5, and 10.5. The work is carried out under electrical load of 240, 420, and 600 Watt. The result indicates that compression ratio affects the rotational speed, brake power, brake torque, brake specific fuel consumption, and thermal efficiency of the gen-set. Optimum compression ratio for the gen-set fuelled with raw biogas is 9.5. At the optimum compression ratio, maximum brake power, brake torque, and thermal efficiency of are 450.37 W, 1.66 Nm, and 46.93%, respectively. Minimum brake specific fuel is 0.59 kg/kWh at the optimum compression ratio.

The Magnetorheological Fluid: Testing on Automotive Braking System

This paper presents the testing of a Magnetorheological brake (MRB) in the braking system of a vehicle. Two techniques are used to determine the capability of the brake system which are the simulation via Matlab Simulink Software and experimental study by using a quarter vehicle test rig. A Proportional-Integral-Derivative (PID) is employed as a wheel speed control as well as to enforce the MRB to produce the required braking torque need by a vehicle. A dynamic test, namely sudden braking test is performed in three rotational speed conditions which are from 127.5 rad/s (1200 rpm) to 31.42 rad/s (300 rpm), 52.37 Rad/s (500 rpm) and 73.31 rad/s (700 rpm) in two different wheel load which are 10 kg and 15 kg, respectively. The behaviours to be assessed are wheel speed response and brake torque produced by the MRB. From the observation, it is concluded that the capability of the MRB in providing the required brake torque is promising and harmony between simulation and experimental response.

Turbocharged spark-ignition engine performance prediction in various inlet charged air temperatures fueled with gasoline–ethanol blends

In this research, the effect of alternative fuels and the inlet charged air temperature is numerically investigated on the performance of a turbocharged spark-ignition engine. For this purpose, a one-dimensional engine and turbocharger model is created in an engine simulation and performance analysis software and validated with former experimental results. Then, the model is run with four fuel types, including two gasoline types with different octane numbers and two ethanol–gasoline blend fuels—E25 and E85. In each case, the inlet charged air temperature is changed from cold to hot condition and performance characteristics such as the spark advance timing, brake torque, brake-specific fuel consumption and thermal efficiency, emissions and the ignition delay and combustion duration are obtained from simulation results. The results illustrate that by decreasing the inlet charged air temperature, the spark timing is more advanced due to less knock and the brake torque increases. Also, the brake-specific fuel consumption and the brake NOx and CO2 decrease and thermal efficiency increases in all fuel types. The results also demonstrate that in higher ethanol percent in blend fuels, all engine performance characteristics improve except brake-specific fuel consumption; as changing the fuel at constant fuel-to-air equivalence ratio from E25 to E85 in various revolutions per minute causes a 5.8% increase in the brake torque, 1.06% increase in the thermal efficiency, 43% and 3.9% decrease in the brake NOx and CO2 and 5.8 °CA decrease in the combustion duration, on average; while the brake-specific fuel consumption and the peak pressure increase 29% and 20%, respectively.