Internal combustion engines

An internal combustion engine, including:

• means defining at least one combustion chamber,
• an exhaust manifold,
• exhaust pipe means connected to the exhaust manifold for conducting exhaust gases away from the combustion chamber,
• means defining an air inlet conduit whereby air for combustion of fuel is introduced into the combustion chamber, said air inlet conduit having a main inlet and at least one auxiliary inlet for introducing main and auxiliary air flows respectively into said air inlet conduit and being formed with a venturi constriction at a position downstream of said main inlet, said auxiliary inlet opening into said air inlet conduit at the position of the narrowest region of said constriction,
• air filter means,
• air heater means connected to receive filtered air from the air filter means for heating said filtered air and comprising at least two members which are secured together to define a central opening through which said exhaust manifold extends, said members together defining a substantially annular passageway which extends about the exhaust manifold in heat-exchange relationship therewith and is provided with an inlet connection connected to the air filter means and with an outlet connection,
• a humidifier connected to receive filtered and heated air from the air heater means for humidifying said filtered and heated air and comprising a vessel for containing humidification liquid, said vessel having an upper region at which it is provided with air inlet connection which is connected to the outlet connection of the air heater means and with an air outlet connection, the vessel having therewithin a sponge member having an upper surface which extends substantially horizontally within the vessel, the shape and size of the upper surface of the sponge member being substantially identical to the shape and size of the horizontal section of the interior space defined by the vessel at the level at which the upper surface is located.
• preheater means connected to receive the filtered and humidified air from the humidifier for heating said air, and comprising a member which defines an opening of substantially the same diameter as the exhaust manifold and the exhaust pipe means and is connected in series between the outlet of the exhaust manifold and the inlet of the exhaust pipe means, and a duct passing diametrically through the opening and having an inlet end which is connected to the air outlet connection of the humidifier vessel and also having an outlet end, and
• an air suction control valve connected between said preheater means and said auxiliary inlet to said air inlet conduit for controlling passage of air from said preheater means to said auxiliary inlet and comprising a valve body defining a passageway having two ends extending therethrough and connected at one end to said auxiliary inlet and at its other end to the outlet end of said duct, the passageway having a reduced diameter portion intermediate its ends, and the valve also comprising a ball positioned in the passageway between the reduced diameter portion and said one end, an abutment member between said ball and said one end, and a resilient member positioned in the passageway and effective between the abutment member and the ball to urge the ball towards said reduced diameter portion of the passageway for blocking the passageway, whereby said air suction control valve operates in response to increase in pressure in the combustion chamber to reduce the flow of air from the preheater means to the auxiliary inlet.