An oil separator is designed for an internal combustion engine with a camshaft system, via which oil separator a medium containing oil-particle-enriched blow-by gases, is influenced to the effect that the oil particles and the blow-by gases are separated and supplied to an oil circuit or to an inlet system of the internal combustion engine. The oil particles are separated from the blow-by gases by rotation of the camshaft system. In order to optimize this oil separator, the camshaft system has at least one camshaft on which a centrifugal blade device acting as the oil separator is effective. The centrifugal blade device conveys the oil particles of the medium against housing walls which are adjacent relative to the camshaft and lead to the oil circuit, with the blow-by gases freed from oil particles being conducted into the inlet system by the pressure conditions prevailing in a crankcase of the internal combustion engine.

A method and a system for diagnosing positive crankcase ventilation (PCV) systems are disclosed. In one example, the method diagnoses a PCV system based on a pressure that may be observed during engine cranking. In another example, the PCV system is diagnosed during vehicle driving conditions after the engine exits cranking.

A breach detection system for an internal combustion engine having a crankcase, an intake manifold, a positive crankcase ventilation valve, a crankcase ventilation tube with a flow control system therein, and a pressure sensor between the flow control system and the crankcase. The flow control system subdivides the crankcase ventilation tube into a plurality of parallel conduits—a first conduit having a normally closed check valve that opens under a first preselected pressure drop in a first direction from the air intake to the crankcase, and a second conduit having either a second check valve that opens under a second preselected pressure drop in a second direction opposite the first direction or a restriction profile having a third preselected pressure drop that is the same in both the first and second direction. When the pressure sensor detects no pressure drop there is a breach in the system.

The invention provides a system for ventilation of a crankcase (217) of an internal combustion engine, the system comprising—an air inlet guide (203, 212) adapted to guide air to at least one cylinder (220) of the engine,—a closed circuit conduit (209) for guiding crankcase gas from the crankcase (217) to the air inlet guide (203, 212),—wherein the system comprises gas detection means (2181, 2182, 2183) positioned in the air inlet guide (203, 212), for detecting crankcase gas in the air inlet guide.

A method of determining the total evaporation rate of fuel from an oil sump of an engine comprising: a) defining for said fuel, a plurality (n-1) of zones, each zone comprising a separate temperature range, and corresponding to a particular fuel constituent portion; b) determining or estimating the mass of said particular fuel constituent portion present in the sump for each zone; c) for each zone, determining an evaporation rate based on oil temperature; and the corresponding mass determined in step b); d) summing the evaporation rates for each zone from step c) to provide said total evaporation rate.

A method for diagnosing a part of a crank case ventilation system of an engine operable in different engine running conditions, the system comprising an electrically driven crank case ventilation, eCCV, separator. The method comprises determining a compared power consumption of the eCCV separator by comparing a current power consumption indicative value of the eCCV separator with a reference value; determining whether or not the compared power consumption achieved as pre-set criteria; and diagnosing a fault in the system in response to determining that the compared power consumption achieves the pre-set criteria.

Systems, devices and methods for diagnosing malfunctioning in a crankcase ventilation (CCV) system are provided. A controller includes a processor and a memory storing instructions that cause the processor to: receive a plurality of pressure values including (i) a first pressure value indicative of a pressure of fluid flowing from a crankcase to a breather assembly of a system, (ii) a second pressure value indicative of a pressure of fluid flowing through a first tube coupled to the breather assembly, and (iii) a third pressure value indicative of a pressure of fluid flowing through a second tube coupled to the breather assembly; determine a pair of pressure differences based on the first pressure value, the second pressure value, and the third pressure value; and detect a malfunctioning in the CCV system based on the pair of pressure differences.

A blowby gas treatment device includes a pressure control valve, a fresh air induction pipe, a first blowby gas pipe, a second blowby gas pipe, a shutoff valve, a one-way valve, and a PCV valve. A leak diagnosis includes a first-stage diagnosis to determine whether or not falling of a pressure in a crank case after closing of the shutoff valve under a non-supercharging condition is normal. A second-stage diagnosis is implemented by moving the pressure control valve from a fully opened state into a fully closed state, and determining whether an intake air quantity in each state is equal to each other. When the intake air quantity in each state is equal to each other, presence of an in-system leak is determined. When a fully closed state intake air quantity is different from a fully opened state intake air quantity, presence of an out-of-system leak is determined.

In an internal combustion engine, the cylinder block includes a first blowby gas passage and a first oil return passage. The cylinder head includes a second blowby gas passage connecting the first blowby gas passage with a connection passage connected with a gas-liquid separator, an oil return chamber separated from a valve operating chamber and the second blowby gas passage by first and second partition walls, respectively, and provided with a first oil return hole connected with the gas-liquid separator, and a second oil return passage connecting the valve operating chamber with the first oil return passage. The first partition wall is formed with a second oil return hole connecting the oil return chamber with the valve operating chamber. The second partition wall is formed with a ventilation hole connecting the oil return chamber with the second blowby gas passage at a higher position than the second oil return hole.

An abnormality diagnosis system of an air-fuel ratio sensor acquires a blowby gas flow ratio showing a ratio of the flow of blowby gas to the flow of gas to a combustion chamber and an output current of an air-fuel ratio sensor during fuel cut control in which an internal combustion engine stops the feed of fuel to the combustion chamber and at a plurality of points of time of different flows of blowby gas passing through a blowby gas passage and flowing to the downstream side of a throttle valve in the intake passage, calculate an output current of the air-fuel ratio sensor corresponding to a blowby gas flow ratio smaller than the blowby gas flow ratios acquired at the plurality of points of time, based on the acquired blowby gas flow ratio and output current, and judge the air-fuel ratio sensor for abnormality based on the calculated output current.