DUAL FUEL ENGINE COMBUSTION CONTROL STRATEGY OPTIMIZING PILOT SHOT QUANTITIES

An engine system operating and control strategy includes autoigniting a directly injected pilot fuel to ignite a primary fuel in a cylinder in a first engine cycle. The strategy further includes comparing data indicative of a heat release in a cylinder in the first engine cycle to phasing error criteria for an earlier pilot shot of the pilot fuel and a later shot of the pilot fuel. A quantity of one or more pilot shots in a subsequent engine cycle is varied, based on the comparison. Pilot shot quantity can be varied closed loop to obtain desired combustion phasing characteristics, such as when a characteristic of a primary fuel is changed during operation. Related apparatus and control logic is also disclosed.