An Experimental Study of Turbocharged Hydrogen Fuelled Internal Combustion Engine

Hydrogen is considered as one of the potential alternate fuel and when compared to other alternate fuels like CNG, LPG, Ethanol etc., it has unique properties due to absence of carbon. In the current work, Hydrogen engine of 2.5 L, four cylinder, spark ignited Turbocharged-Intercooled engine is developed for Mini Bus application. Multi-point fuel injection system is used for injecting the hydrogen in the intake manifold. Initially, boost simulation is performed to select the optimum compression ratio and turbocharger. The literature review has shown that in-order to get the minimum NOx emissions Hydrogen engines must be operated between equivalence ratios ranging from 0.5 to 0.6. In the present study, full throttle performance is conducted mainly with the above equivalence ratio range with minimum advance for Maximum Brake Torque (MBT) ignition timing. At each operating point, the performance, emissions and combustion parameters are recorded and analyzed in detail. It has been observed that a power of 66.7 kW @ 3200 rpm and a torque of 180 Nm @ 2000 rpm are achieved by using neat Hydrogen on Turbo charged engine. The base performance data is compared with CNG naturally aspirated engine (running using stoichiometric operation) and it has been observed that Hydrogen engine is having similar performance above 2000 rpm, however there is torque drop due to operation on Hydrogen which has limitation of the turbocharger to boost at lower engine speeds (running using equivalence ratio ranging from 0.5 to 0.6). Such lean operation also helps to avoid backfire which the hydrogen engine is quite vulnerable. It has also been observed that the combustion stability of the Hydrogen engine is very good at all Indicated Mean Effective Pressure (IMEP) values irrespective of the engine speed with a Coefficient of Variance (COV) around 1-2%.