Abstract: A seal structure for an internal combustion engine comprising: a cover side seal member which extends on upper surface sides or lower surface sides of both of an engine main body section and a chain casing and pressed and held against a cover member; a casing side seal member arranged at left or right end section of one end surfaces of the engine main body section onto which the chain casing is attached and pressed and held against the chain casing; a receiving concavity formed to extend on a junction surface of the chain casing to the cover member; and an extremely thick connection block section formed integrally on one end section of the casing side seal member, fitted into and retained by the receiving concavity, and projected more toward the cover member side than a junction surface of the chain casing to the cover member in a free state.

Abstract: A blow-by gas inlet structure of an oil separator adapted to be placed above a cam chamber of an internal combustion engine, comprises a plate that forms a bottom wall of the oil separator; a blow-by gas inlet opening that is formed in the plate; an oil blocking structure that is provided below the blow-by gas inlet opening in a manner to divide the blow-by gas inlet opening into front and rear inlet openings through which the blow-by gas is led into the oil separator, the front and rear inlet openings being arranged in a first direction; and a transverse rib that is provided on the oil blocking structure and extends in a second direction that is perpendicular to the first direction.

Abstract: A head cover having a lubrication structure, and having a box shape, the head cover includes: a side wall; a lower surface side which is opened, and which includes a lower surface circumference portion that is fixed to an upper portion of an engine; a lubrication opening which is opened in an upward direction, and which is disposed on an outer side of the head cover; and a lubrication passage extending from the side wall in an outward direction, and connecting the lubrication opening and an inside of the head cover.

Abstract: A head cover having a lubrication structure, and having a box shape, the head cover includes: a side wall; a lower surface side which is opened, and which includes a lower surface circumference portion that is fixed to an upper portion of an engine; a lubrication opening which is opened in an upward direction, and which is disposed on an outer side of the head cover; and a lubrication passage extending from the side wall in an outward direction, and connecting the lubrication opening and an inside of the head cover.

Abstract: A method and apparatus for diagnosing an electrochemical sensor that detects the concentration of a gas are operative for diagnosing whether or not the sensor is in an error state due to a rise in a resistance in the electrolyte of the sensor. Such detection is made on the basis of a current flowing between a sensing electrode and an opposite electrode or a voltage corresponding to the current. A method for diagnosing an electrochemical sensor having a solid or liquid electrolyte between a sensing electrode and an opposite electrode detects the concentration of the gas to be detected on the basis of a current flowing between the sensing electrode and the opposite electrode, or a voltage corresponding to the current. Whether or not the electrochemical sensor is in an error state is diagnosed on the basis of a resistance of the electrolyte between the two electrodes of the electrolyte.

Abstract: An oil separator disposed inside a cylinder head cover of an internal combustion engine. The oil separator includes a body section defining an elongate separator chamber and having a blowby gas inlet and a blowby gas outlet. A partition wall is disposed to divide the separator chamber into an inlet chamber at side of the blowby gas inlet and an outlet chamber at side of the blowby gas outlet. The partition wall is formed with a plurality of passage holes each of which is triangular in cross-section. A collision plate is disposed inside the outlet chamber and located opposite to the passage holes of the partition wall. A slit-like opening is defined by a lower section of the collision plate and communicated with a drain section for discharging oil separated from blowby gas into a valve operating chamber.

Abstract: An oil separator disposed inside a cylinder head cover of an internal combustion engine. The oil separator includes a body section defining an elongate separator chamber and having a blowby gas inlet and a blowby gas outlet. A partition wall is disposed to divide the separator chamber into an inlet chamber at side of the blowby gas inlet and an outlet chamber at side of the blowby gas outlet. The partition wall is formed with a plurality of passage holes each of which is triangular in cross-section. A collision plate is disposed inside the outlet chamber and located opposite to the passage holes of the partition wall. A slit-like opening is defined by a lower section of the collision plate and communicated with a drain section for discharging oil separated from blowby gas into a valve operating chamber.

Abstract: A method and apparatus for diagnosing an electrochemical sensor that detects the concentration of a gas are operative for diagnosing whether or not the sensor is in an error state due to a rise in a resistance in the electrolyte of the sensor. Such detection is made on the basis of a current flowing between a sensing electrode and an opposite electrode or a voltage corresponding to the current. A method for diagnosing an electrochemical sensor having a solid or liquid electrolyte between a sensing electrode and an opposite electrode detects the concentration of the gas to be detected on the basis of a current flowing between the sensing electrode and the opposite electrode, or a voltage corresponding to the current. Whether or not the electrochemical sensor is in an error state is diagnosed on the basis of a resistance of the electrolyte between the two electrodes of the electrolyte.

Abstract: An oil pan made from a resin material, the oil pan includes: a bottom wall; and side walls; the bottom wall including a plurality of ribs protruding from the outer wall surface, each of the ribs having; a base end portion protruding from the outer wall surface of the bottom wall, and having a tip end surface, and a tip end portion protruding from the tip end surface, the tip end portion being connected with the base end portion at a connection portion, the connection portion at which the base end portion and the tip end portion are connected with each other, which has a width that is equal to or smaller than a width of a portion at a base end position of the base end portion, and equal to or smaller than a width of a portion at a tip end position of the tip end portion.

Abstract: An oil separator provided in combination with a cylinder head cover of an internal combustion engine. The oil separator includes a separator cover fixed to an inner surface of the cylinder head cover defining a space extending in a first direction perpendicular to axis of a camshaft in plan, between the separator cover and the cylinder head cover. The separator cover has an opening through which the space is opened to a valve operating chamber. A partition wall is provided to define in the space an inlet-side separator chamber and an outlet-side separator. The partition wall extends in a second direction parallel with the axis of the camshaft and being formed with a plurality of fine passages. Additionally, a plurality of projection walls project from a part of the inner surface of the cylinder head cover which faces the valve operating chamber through the opening.

Abstract: An oil separator provided in combination with a cylinder head cover of an internal combustion engine. The oil separator includes a separator cover fixed to an inner surface of the cylinder head cover defining a space extending in a first direction perpendicular to axis of a camshaft in plan, between the separator cover and the cylinder head cover. The separator cover has an opening through which the space is opened to a valve operating chamber. A partition wall is provided to define in the space an inlet-side separator chamber and an outlet-side separator. The partition wall extends in a second direction parallel with the axis of the camshaft and being formed with a plurality of fine passages. Additionally, a plurality of projection walls project from a part of the inner surface of the cylinder head cover which faces the valve operating chamber through the opening.