Abstract: A control apparatus calculates an upstream side pressure and temperature on an upstream side of a turbine impeller and a turbine flow rate, and calculates an upper limit threshold value of an opening degree level of a variable nozzle of a turbo supercharger such that a turbine pressure ratio is equal to or less than a predetermined ratio on a basis of the turbine flow rate and a pressure ratio•turbine flow rate characteristic. The pressure ratio•turbine flow rate characteristic is pre-stored information indicating a relationship between the turbine pressure ratio, the turbine flow rate, and the opening degree level of the variable nozzle. The control apparatus controls an opening degree of the variable nozzle so as to be an opening degree equal to or less than the upper limit threshold value.

Abstract: In an engine that includes a liquid fuel injector and a gaseous fuel injector connected to an intake pipe via a fuel passage and that switches fuel supplied into intake air between liquid fuel and gaseous fuel, an electronic control unit increases fuel in an amount required to fill the fuel passage with gaseous fuel at the time of initial fuel injection from the gaseous fuel injector after switching from liquid fuel to gaseous fuel.

Abstract: An internal-combustion engine has a turbo supercharger. A control apparatus calculates a fuel flow rate based on an injection quantity of fuel in the engine and a number of revolutions of the engine. The control apparatus calculates an upstream side pressure and temperature on an upstream side of a turbine impeller and a turbine flow rate. The control apparatus calculates an upper limit threshold value of an opening degree level of a variable nozzle of the turbo supercharger such that a turbine pressure ratio is equal to or less than a predetermined ratio on a basis of the turbine flow rate and a pressure ratio•turbine flow rate characteristic. The pressure ratio•turbine flow rate characteristic is pre-stored information indicating a relationship between the turbine pressure ratio, the turbine flow rate, and the opening degree level of the variable nozzle.

Abstract: In an engine that includes a liquid fuel injector and a gaseous fuel injector connected to an intake pipe via a fuel passage and that switches fuel supplied into intake air between liquid fuel and gaseous fuel, an electronic control unit increases fuel in an amount required to fill the fuel passage with gaseous fuel at the time of initial fuel injection from the gaseous fuel injector after switching from liquid fuel to gaseous fuel,