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The electric or hybrid vehicles need fast switching operation in order to ensure the quick-response of the motors. This process is carried out by compact direct-current contactors which are designed to perform the switching over multiple cycles. During the contact separation, the gas between the contacts breaks down and the resulting thermal arc provides a conductive channel that sustains the current. Until the arc is quenched, the current continues to flow through the contacts despite the physical separation. This unintended flow of current could lead to a larger response time than the safe operation limits. We perform high-fidelity simulation of thermal arc in hydrogen-nitrogen mixture environment under external magnetic field of 1 Tesla. The hydrogen enrichment level is kept at 0%, 40%, 50% and 80%. The contacts are separated at 8 m/s. It is demonstrated that the increase in hydrogen concentration leads to smaller arc lifetime thereby improving the circuit interruption performance.

In this study, experiments were carried out to evaluate fuel consumption and exhaust emissions of carbon monoxide (CO), oxides of nitrogen (NOx) and hydrocarbons (HC) with compressed natural gas (CNG) and gasoline fueled SI engine powered vehicles. Studies were carried out to evaluate optimum spark timing to operate both on CNG as well as gasoline mode for fuel consumption and emissions. In this connection, mass emission tests were carried out at various spark timings. Conversion efficiency of a 3-way catalytic converter was also evaluated at different air-fuel ratio for CNG operation. The results showed that exhaust emissions of CO and NOx were significantly less with CNG as compared to gasoline. Optimum spark timing for better fuel economy and lower emissions on gasoline and CNG modes were 10° before TDC and 24° to 26° before TDC respectively.