Control system for internal combustion engine and inert gas concentration detecting device for compressed natural gas

摘要

In a control system that includes a pressure accumulating portion that supplies CNG to a fuel injection valve and a regulator that adjusts a pressure in the pressure accumulating portion to a set pressure and of which a valve element opens when CNG is supplied to the pressure accumulating portion and closes when supply of CNG to the pressure accumulating portion is shut off, a control parameter relating to a combustion state in an internal combustion engine is controlled (S105) on the basis of a length of a period (Δtv) during which an opening degree of the valve element reduces from a first predetermined opening degree to a second predetermined opening degree (S102) when the pressure in the pressure accumulating portion is adjusted to the set pressure by the regulator.