Improvement of engine cold start capability using supercapacitor and lead-acid battery hybrid

Supercapacitors can provide the transient power that the cranking need in low temperature. Aiming to reduce the volume of lead acid battery and the cost of the power system, supercapacitor and lead acid battery hybrid systems are investigated as power sources for diesel engine cold starting by using cold starting test and road test. This paper focuses on the requirement of capacitance and effective series resistance of supercapacitor in hybrid system. Different combinations of batteries and supercapacitors are tested for suitable solution. The lab result proves that the internal resistance of supercapacitor is the key to enhance the cold cranking capacity. The experiment in lab and the final road test, prove the aqueous C/C supercapacitor and battery hybrid systems to be valid and economical. About 5000 sets have been installed on commercial vehicle from 2006.