A blow-by gas leak diagnostic device includes a first PCV flow path, a second PCV flow path, a fresh air inlet, a pressure measurement unit, a first valve that opens and closes the first PCV flow path, a second valve that opens and closes the second PCV flow path, a third valve that opens and closes the fresh air inlet, a valve control unit, and a leak diagnosis unit. The valve control unit controls an opening degree of the third valve when a downstream side of an intake manifold with respect to a throttle valve has a negative pressure, and the second valve is in a closed state. The leak diagnosis unit diagnoses presence or absence of a leak in the first PCV flow path on the basis of an inner pressure of the first PCV flow path measured by the pressure measurement unit.

An engine oil dipstick for monitoring an internal combustion engine comprises a processor and a sensor module. The sensor module is configured to sense a characteristic of the internal combustion engine and to output data representative of the sensed characteristic to the processor. The engine oil dipstick is configured to provide a housing for the processor. The processor is configured to determine a value representative of the firing frequency of the internal combustion engine based on the output data.

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 method for monitoring crankcase pressure, in which a learning curve is calculated according to a target-actual deviation of the crankcase pressure, the target crankcase pressure is adjusted according to the learning curve, and a limit curve is calculated according to the target crankcase pressure. The actual crankcase pressure is monitored for exceedance of the limit curve. After an engine start, upon identification of a steady-state operation of the internal combustion engine, the actual crankcase pressure is compared with a limit value and, if the limit value is identified as being exceeded, the learning curve and, as a result, the limit curve are reset to their initial values.

An engine oil filler cap for monitoring an internal combustion engine comprises: a processor; and a sensor module comprising a pressure sensor configured to sense crankcase pressure of the internal combustion engine and to output data representative of the sensed crankcase pressure to the processor. The engine oil filler cap is configured to provide a housing for the processor. The processor is configured to determine a value representative of the firing frequency of the internal combustion engine based on the output data.

Various systems and methods are provided for reducing an amount of oil reaching a crankcase overpressure sensor. In one example, a system may include a cast wall protruding perpendicularly from an internal wall of crankcase, the cast wall at least partially surrounding a sensor port for a crankcase overpressure (COP) sensor, the sensor port fluidically coupled to the COP sensor via an internal passage; and a cover plate fixedly coupled to the cast wall, the cover plate parallel to the internal wall. In this way, oil may be blocked from reaching the COP sensor, while air may flow through the internal passage to the COP sensor.

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.

Methods and systems are provided for monitoring a crankcase ventilation system. In one example, a method may include diagnosing a breach in a crankcase vent tube based on a regression of measurements of pressure in the crankcase vent tube. The regression allows the pressure measurements to be extended across an entire range of operating air flows and the breach may be identified by comparing the regressed pressure measurements to expected crankcase vent tube pressures.

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 method and a device for checking the functionality of a crankcase ventilation system of an internal combustion engine is provided. The system has a low-load vent line and a high-load vent line between a crankcase outlet of a crankcase and a respectively associated introduction point into an air path of the internal combustion engine, in which method and device the pressure prevailing in the crankcase is measured by a crankcase pressure sensor and is compared with a crankcase pressure modeled on the assumption of a fault-free crankcase ventilation system, and in which method and device information items regarding the presence of a fault and of an associated fault location in the crankcase ventilation system are determined from the comparison result.