Gaseous metering control for dual fluid injector

Abstract

A fuel injection system () for delivering metered amounts fuel into the combustion chamber or cylinder of an engine. The fuel delivered can selectively comprise a gaseous fuel, a liquid fuel or a fuel mixture comprising the gaseous fuel and the liquid fuel. When the fuel delivered comprises a mixture of the gaseous fuel and the liquid fuel, the quantity of liquid fuel comprises a metered quantity. The quantity of gaseous fuel also comprises a metered quantity, with the metering of the gaseous fuel being regulated by prediction. The injection event involves delivering the liquid fuel and the gaseous fuel, with the metering of the gaseous fuel delivered being adjusted to allow for the quantity of liquid fuel delivered with the gaseous fuel. The injection system () comprises a liquid fuel circuit () and a gaseous fuel circuit (), both communicating with a fuel delivery injector () that delivers fuel to the combustion chamber. The fuel injection system () further comprises an electronic control unit (ECU) for controlling operation of the fuel injection system (). The ECU controls operation of the fuel delivery injector () and a fluid metering injector (). The ECU determines the proportions of liquid fuel and gaseous fuel required to meet the fuelling demand. The ECU operates the fluid metering injector () to deliver the required quantity of liquid fuel into a holding chamber within the fuel delivery injector (). The ECU also predicts the gaseous fuel flow required to deliver the necessary proportion of gaseous fuel and operates the fuel delivery injector () accordingly. In particular, the ECU refers to a 'look-up' map or table to determine the operating parameters of the fuel delivery injector () to deliver the necessary quantity of gaseous fuel in conjunction with the metered quantity of liquid fuel.