Fluid control valve including a valve body and an energizing member. The body is engaged with one end of a rotating shaft and moves along an axial direction of the shaft based on shaft rotation. The body opens and closes a first opening by the outer periphery, and one end comes into contact with and separates from a second opening. The member energizes the body on another end side of the shaft. A portion abutting on the second opening and a flow passage in which a fluid flows are at the one end of the body in the case where the first opening is fully closed. Since a valve-closed position of the body can be secured, and fluid flows in the flow passage, when a low flow rate is controlled, a stable flow rate is secured without closing the second opening which is a suction port in a valve-closed position.

A method for monitoring a secondary air supply in an internal combustion engine. The method includes: a) determining, with the aid of a throttle equation and according to a pressure in the secondary air supply, a first secondary air mass flow in relation to the effective throttle area; b) determining a second secondary air mass flow based on a measured exhaust gas lambda value and taking into account a primary air mass flow of the internal combustion engine and a supplied fuel mass flow; c) deriving an effective throttle area from the first secondary air mass flow determined in step a) and the second secondary air mass flow determined in step b); d) monitoring the effective throttle area obtained in this way using at least one specified threshold value.

A method for monitoring a secondary air supply in an internal combustion engine. The method includes: a) determining, with the aid of a throttle equation and according to a pressure in the secondary air supply, a first secondary air mass flow in relation to the effective throttle area; b) determining a second secondary air mass flow based on a measured exhaust gas lambda value and taking into account a primary air mass flow of the internal combustion engine and a supplied fuel mass flow; c) deriving an effective throttle area from the first secondary air mass flow determined in step a) and the second secondary air mass flow determined in step b); d) monitoring the effective throttle area obtained in this way using at least one specified threshold value.

A process relating to a two-stroke cycle internal combustion engine to control the pressure and/or the temperature of the gaseous blend inside the combustion chamber at the time of ignition of combustion, while the air/fuel mixture is maintained close to the stoichiometric ratio. The process is mainly based on high compression by an auxiliary compressor of air that is accumulated in a reservoir. The compressed air is typically injected at two different temperatures, one being relatively cold and the other being relatively hot, as heated by the heat energy recovered from exhaust gases or heaters. The intake compressed air is carried out with predetermined quantity from both temperatures as an injection into the cylinder which already contains a predetermined quantity of the burnt gases from the previous combustion cycle.