A method for positive crankcase ventilation diagnosis in an engine system with an engine, an intake duct connected to the engine, a PCV line connecting a crankcase of the engine with the intake duct and a sensor for determining an actual PCV pressure (p.sub.act) in the PCV line. The method comprises the steps of: performing a diagnosis measurement by repeatedly determining at least one input parameter (p.sub.int, n.sub.e, p.sub.atm, Q), which is linked to the operation of the engine system, and the actual PCV pressure (p.sub.act), to obtain a plurality of data samples for a plurality of sample times (t.sub.s); using a prediction model (M) to determine a predicted PCV pressure (p.sub.pre); and comparing the actual PCV pressure (p.sub.act) with the predicted PCV pressure (p.sub.pre) to diagnose the PCV line, wherein a diagnosis of the PCV line is based on a model error (p.sub.err).

A method and a control device for monitoring the pressure in a crankcase of an internal combustion engine. The desired values for the pressure in the crankcase are defined for a plurality of operating points of the internal combustion engine. Furthermore, at least one of the defined desired pressure values is modified during operation of the internal combustion engine.

A fault detection unit of an internal combustion engine includes a recirculation pipe connected with an upstream-side part of an intake pipe of the internal combustion engine upstream of a supercharger, the recirculation pipe to supply an evaporated fuel that is unburned and is generated in the internal combustion engine to the intake pipe, and a fault detection unit to detect a leakage occurrence of the recirculation pipe based on a crank-case inner pressure of the internal combustion engine when the internal combustion engine is operating in a specified operation condition that the crank-case inner pressure is a positive pressure.

The disclosure relates to a method and a device for checking the functionality of a crankcase ventilation system of an internal combustion engine. The crankcase ventilation system includes two crankcase ventilation lines arranged between a crankcase outlet of a crankcase and an associated introduction point into an air path of the internal combustion engine, via which crankcase ventilation lines gas can be introduced from the crankcase into the air path. The method includes measuring a pressure in the crankcase, supplying the measured pressure values to a control unit, and calculating the gradient of the measured pressure. The method also includes performing a gradient check, checking whether the gradient satisfies a specified criterion, and returning to the measurement of the pressure if the gradient satisfies the specified criterion. The method also includes recording an entry in a fault memory if the gradient does not satisfy the specified criterion.

A diagnosis device is intended for an internal combustion engine including a supercharger, a blow-by gas passage that communicates between a portion of an intake passage and a crankcase, a PCV pressure sensor that detects a PCV pressure in the blow-by gas passage, and a crankshaft. The device executes specifying a specific period for which the amount of fluctuations in the intake air amount per unit time is a prescribed value or more on condition that the intake air amount is a determination air amount or more, calculating the amount of fluctuations in the PCV pressure during the specific period, and determining, based on the amount of fluctuations in the PCV pressure, the presence of an abnormality in the blow-by gas passage. The device sets the determination air amount to a smaller value when the rotational speed of the crankshaft is high than when the rotational speed is low.

An apparatus for diagnosing a blow-by gas recirculation system may include a head portion of an engine configured to form a combustion chamber, a head cover provided on an upper portion of the head portion, a crankcase formed on a lower portion of the combustion chamber, an intake line through which an intake-air flows to the combustion chamber, a breather hose connecting the crankcase and the intake line at an upstream side of a compressor mounted on the intake line, a PCV hose connecting the crankcase and a surge tank, and a controller configured to determine an abnormality of the breather hose based on a modelled crankcase pressure determined from an atmospheric pressure and an intake flow rate introduced through a throttle valve and a measured crankcase pressure measured from a pressure sensor configured to measure an internal pressure of the crankcase.

A positive crankcase ventilation valve for an engine is provided with a valve body defining apertures fluidly coupling a crankcase and an intake manifold of the engine, with each aperture sized to prevent an entrained oil droplet from flowing therethrough. The valve has a valve element supported by the body to selectively cover at least one of the apertures in response to a pressure difference between the manifold and the crankcase to provide variable air flow from the crankcase to the intake manifold. A method includes, in response to an increasing absolute pressure difference between the manifold and the crankcase, passively moving a valve element to selectively cover apertures fluidly coupling the crankcase and the manifold to control an air flow from the crankcase to the intake manifold to a predetermined variable flow profile, and separating oil droplets from the air flow via the apertures.

A method for diagnosing a crankcase system of an internal combustion engine. A pressure value is captured in a crankcase system. A pressure value of a reference pressure is ascertained or a pressure value to be expected in the crankcase system is modeled. A gradient of the pressure value in the crankcase system and a gradient of the reference pressure or the modeled pressure in the crankcase system is formed. The two formed gradients are integrated over time. The function of the crankcase system is evaluated based on the values obtained by the integrations. A control device as well as an internal combustion engine for carrying out the method are provided.

A system for diagnosing a crankcase ventilation system of an internal combustion engine. The system includes an internal combustion engine with at least one combustion chamber. The combustion chamber is bounded by a cylinder head, a cylinder in an engine block, and a piston. The piston is connected via a connecting rod to a crankshaft, which is disposed in a crankcase. An air supply system feeds fresh air into the combustion chamber of the internal combustion engine. At least one aeration line connects the air supply system to the crankcase. At least one vent line, which is different from the aeration line, connect the crankcase to the air supply system. A pressure sensor is disposed in the crankcase or the aeration line. A method for diagnosing a crankcase ventilation system and a control device for carrying out such a method are also provided.

Methods for preventing a premature ignition of a cylinder charge in advance of a planned ignition point in an internal combustion engine are provided. In one method, a pressure in a crankcase of the internal combustion engine is adjusted so as to prevent lubricating oil constituents from being transported from the crankcase to a combustion chamber of a cylinder of the internal combustion engine due to a pressure ratio between the crankcase and the combustion chamber. In another method, an ignition point for a cylinder of the internal combustion engine is adjusted in a given operating range of the internal combustion engine in such a way that the adjusted ignition point brings about a knocking combustion in the cylinder. Internal combustion engines having a device for preventing a premature ignition of a cylinder charge in advance of a planned ignition point are also provided.