Exhaust valve arrangement and a fuel system incorporating an exhaust valve arrangement

Abstract

An exhaust valve arrangement for use in a combustion chamber of a compression ignition internal combustion engine, includes a piston which is movable outwardly from the combustion chamber in response to pressure generated within the combustion chamber as a result of combustion, and an outer sleeve within which the piston is movable. The outer sleeve is an exhaust valve which is actuable between open and closed positions to open and close, respectively, an exhaust passage from the combustion chamber. The exhaust valve arrangement further includes a pump chamber for receiving fluid, and a pumping plunger coupled to the piston and movable with the piston so as to pressurise fluid (e.g. fuel) within the pump chamber as the piston is urged outwardly from the combustion chamber. The pressure within the pump chamber is proportional to cylinder pressure and is sensed by a sensor which provides an output signal to an Engine Control Unit (ECU). An accumulator volume receives fluid that is pressurised within the pump chamber. Where the fluid is fuel, the accumulator volume is arranged to deliver fuel to one or more injectors of a common rail fuel injection system. Alternatively the accumulator volume may be arranged to deliver pressurised fluid to one or more engine systems e.g. for actuation purposes.