An engine bed plate includes a plurality of partition walls provided in a casing and dividing an interior of the casing to define a plurality of crank chambers. A first ventilation hole is provided in a front wall and each of the plurality of partition walls. The first ventilation hole is formed in a horizontal direction to ventilate the plurality of crank chambers.

Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits.

A positive crankcase ventilation (PCV) valve mounting structure has a blow-by gas passage with an upstream-side passage portion and a down-stream-side passage portion positioned in a cylinder head and an intake manifold, respectively. The blow-by gas passage may receive the PCV valve therein such that an upstream side portion of a valve case of the PCV valve is positioned within the upstream-side passage portion and that a downstream side portion of the valve case is positioned within the down-stream-side passage portion when the cylinder head and the intake manifold are joined together. A gasket may seal the cylinder head to the intake manifold and may include a seal portion positioned between the valve case of the PCV valve and at least one of the cylinder head and the intake manifold.

This blow-by gas system is provided with: a blow-by gas flow path through which a blow-by gas discharged from an internal combustion engine passes; and an oil separator disposed midway along the blow-by gas flow path. A downstream end of the blow-by gas flow path connects to at least one of a predetermined portion of an intake passageway and a midway portion of an air introduction passageway. The predetermined portion is a portion at which at least some of the blow-by gas that has flowed into the intake passageway flows into the air introduction passageway together with an intake air in the intake passageway.

An abnormality determination device of an internal combustion engine in which a breather line connects an intake-air path positioned upstream from a forced-induction system and a crankcase includes an intake-air flow rate sensor that detects an intake air flow rate in the intake-air path, a pressure sensor that detects a pressure of the breather line, and an abnormality determination unit that determines abnormality of the breather line. The abnormality determination unit estimates an intake air resistance of the intake-air path from the pressure when the engine is under low load conditions under which the intake air flow rate is less than a predetermined value and the pressure when the engine is under high load conditions under which the intake air flow rate is the predetermined value or greater and determines abnormality of the breather line when the intake air resistance is less than a threshold.

A cable holder for securing a plurality of vehicle engine cables while simulating a vehicle engine distributor comprises a shaft portion and a cap portion provided at a top of the shaft portion. The cap portion cooperates with the shaft portion to define a central passageway therethrough. At least one opening is provided proximate a bottom of the shaft portion and opening to the central passageway, and a plurality of upper apertures are provided proximate a top of the cap portion and opening to the central passageway. A hollow path is formed between the at least one lower aperture and plurality of upper apertures to channel a plurality of vehicle engine cables through the cable holder.

An abnormality assessment device includes an on-off valve that shuts an intake path on an upstream side of a connection portion of a breather line with respect to the intake path and an abnormality assessment element that assesses abnormality of the breather line. The abnormality assessment element assesses abnormality of the breather line based on a difference between an intake flow rate that is detected by an intake flow rate sensor and a target intake flow rate in a case where the on-off valve is closed.

A breather is provided for an internal combustion engine that is configured to be mounted to provide a compact, space efficient packaging arrangement for the internal combustion engine. The breather includes a housing with a front wall, a rear wall opposite the front wall, and a plurality of sidewalls connecting the front and rear walls. The front wall is configured for attachment to the rearward end of the valve cover.

An internal combustion engine includes a first blow-by gas passage defined in a second wall. The internal combustion engine includes a second blow-by gas passage defined in a third wall. The internal combustion engine includes a third blow-by gas passage defined in a fourth wall. The first blow-by gas passage to the third blow-by gas passage connect an oil chamber and an oil separator to each other. The second wall includes a first connecting path. The fourth wall includes a second connecting path. The first connecting path connects the first crank chamber and the second crank chamber. The second connecting path connects the third crank chamber and the fourth crank chamber to each other. The third wall does not have a passage connecting the second crank chamber and the third crank chamber to each other.

The internal combustion engine includes a second separator, a connection pipe, and a pressure sensor. Inside the second separator, a main chamber located in the cylinder head cover, and a first sub-chamber and a second sub-chamber located in a joint portion located outside the cylinder head cover are formed. The first sub-chamber and the second sub-chamber are partitioned by partition walls. A communication hole connecting the first sub-chamber and the second sub-chamber is formed in the partition wall. The first sub-chamber is connected to the main chamber via a throttle portion. A first connection port connected to the first sub-chamber and a second connection port connected to the second sub-chamber are formed in the joint portion. The first connection port is connected to the intake passage via a connection pipe. The second connection port is connected to the pressure sensor.