A method for improved engine operation

An method for starting and operating an engine 11 of a mild hybrid vehicle 5 following start-up is disclosed for an engine 11 having low and high voltage starting devices 13 and 14 controlled by an electronic controller 10. The method comprises using the high voltage starting device 14 as a motor to crank the engine 11 whenever possible so as to partially discharge a high voltage battery 18 and then using the high voltage starting device 14 as a generator after starting the engine 11 if the exhaust gas temperature needs to be increased so as to assist with light-off of one or more exhaust gas aftertreatment devices 6.