An internal combustion engine (1) includes an internal combustion engine main body (20), a head cover (11, 15) attached to an upper end part of the internal combustion engine main body, and an exhaust system (34) connected to the internal combustion engine main body, and a gas-liquid separator (45, 60) for blowby gas provided in the head cover. A part of the exhaust system is positioned adjacent to the internal combustion engine main body in a first direction (X) along a cylinder row, and the gas-liquid separator is positioned in the head cover so as to be offset in the first direction.

An internal combustion engine has a plurality of cylinders and transmission arranged adjoining the engine. If designating an average height of a combustion chamber in a region inside from a virtual cylindrical surface passing through center of a valve body of an intake valve and extending in a circumferential direction of each cylinder when a piston is at top dead center, as center height, and designating average of a height of the combustion chamber in a region outside from the virtual cylindrical surface when the piston is at top dead center, as peripheral height, the combustion chambers form a center height of a transmission side cylinder positioned most to the transmission side among the plurality of cylinders is higher than center heights of usual cylinders including one cylinder other than the transmission side cylinder and a peripheral height at the transmission side cylinder lower than peripheral heights of usual cylinders.

An internal combustion engine has a plurality of cylinders and transmission arranged adjoining the engine. If designating an average height of a combustion chamber in a region inside from a virtual cylindrical surface passing through center of a valve body of an intake valve and extending in a circumferential direction of each cylinder when a piston is at top dead center, as center height, and designating average of a height of the combustion chamber in a region outside from the virtual cylindrical surface when the piston is at top dead center, as peripheral height, the combustion chambers form a center height of a transmission side cylinder positioned most to the transmission side among the plurality of cylinders is higher than center heights of usual cylinders including one cylinder other than the transmission side cylinder and a peripheral height at the transmission side cylinder lower than peripheral heights of usual cylinders.

An engine includes: an engine main body including a plurality of cylinders; a plurality of exhaust pipes connected to exhaust sides of the plurality of cylinders; a plurality of throttle valves positioned on intake sides of the plurality of cylinders; a catalyst device connected to the plurality of exhaust pipes; and a controller configured to control opening and/or closing operations of the plurality of throttle valves. One of the exhaust pipes is formed shorter than other exhaust pipe. And the controller opens one of the throttle valves upstream of the one of the exhaust pipes at a higher speed or a larger opening degree than other throttle valve upstream of the other exhaust pipe when the engine is started.

An intake manifold is connected to a cylinder of an engine, and extends backward from the cylinder. A throttle body is attached to the intake manifold. As seen in a plan view of an outboard motor, the throttle body is disposed backward of a head cover, while being disposed inward of a lateral end of the intake manifold in a right-and-left direction of the outboard motor.

An alternator adapter for a generator engine includes a main body defining an airflow chamber. The main body includes an airflow outlet in a first end of the main body, an engine shaft opening in a second end of the main body opposite the first end, and an airflow inlet between the first end and the second end. The alternator adaptor also includes an engine mount coupled to the first end of the main body around the airflow outlet and aligned with the engine shaft opening, and an alternator mount coupled to the second end of the main body around the engine shaft opening.

An engine is provided with: an engine body; and a top cover that covers the engine body, wherein at least a pair of engaging claws are provided to lateral walls, on both sides, of the top cover so as to extend downward, and a pair of engaging holes with which the engaging claws engage are provided to the engine body side. Each of the engaging claws is provided with a plate section that is provided so as to extend downward, and a bulging section that is provided to the leading end of the plate section and that bulges inward from the plate section, and the bulging section engages with the bottom surface of an inner wall section of the corresponding engaging hole.

An engine is provided with: an engine body; and a top cover that covers the engine body, wherein at least a pair of engaging claws are provided to lateral walls, on both sides, of the top cover so as to extend downward, and a pair of engaging holes with which the engaging claws engage are provided to the engine body side. Each of the engaging claws is provided with a plate section that is provided so as to extend downward, and a bulging section that is provided to the leading end of the plate section and that bulges inward from the plate section, and the bulging section engages with the bottom surface of an inner wall section of the corresponding engaging hole.

The disclosure relates to a method for operating an internal combustion engine of a truck or omnibus, in particular a truck or omnibus with a permissible total mass of at least 3.5 tonnes, wherein (i) an electrolysis unit for the production of hydrogen, water is split into hydrogen and oxygen, (ii) a carbon dioxide sorption unit extracts carbon dioxide from the ambient air, (iii) the hydrogen and the carbon dioxide are fed to a methanol synthesis unit for the production of methanol, and are synthesised therein to methanol, (iv) a photovoltaic unit absorbs solar energy and converts it into electrical energy. The electrolysis unit, the carbon dioxide sorption unit and the methanol synthesis unit are powered by the electrical energy generated in the photovoltaic unit. The methanol produced is transported by means of a distributor system to at least one tank of the truck or omnibus, and is supplied from the tank as required to the internal combustion engine, and therein is combusted to generate mechanical energy.

A blow-by gas treatment device includes a first blow-by gas pipe, a second blow-by gas pipe, a first pipe joint located on a first head cover, the first blow-by gas pipe being connected to the first pipe joint, a second pipe joint located on a second head cover, the second blow-by gas pipe being connected to the second pipe joint, a first union located on the first pipe joint, a second union located on the second pipe joint, and a pressure sensor connected to the first pipe joint by the first union and connected to the second pipe joint by the second union.