The aerosol diluting apparatus includes a first diluting unit to provide a first modified sample flow by combining an aerosol sample flow with a first diluting gas flow, an ejector unit to draw the first modified sample flow from the first diluting unit to the ejector unit and to provide a second modified sample flow by mixing a second dilution gas flow with the first modified sample flow, a control unit, and a control valve, wherein the control unit and the control valve are arranged to adjust flow rate of the second dilution gas flow according to an inlet pressure of the aerosol sample flow, so as to keep the dilution factor of the diluting apparatus substantially independent of the inlet pressure.

The invention relates to a method for controlling the pressure of the exhaust gas of a machine, in particular an internal combustion engine. The exhaust gas is discharged from the machine via an exhaust gas line, and the exhaust gas line has a regulating device, preferably comprising a throttle valve or a throttle flap, said regulating device delimiting a pressure-regulated section of the exhaust gas line. Gas, preferably air, which is regulated into the pressure-regulated section via a compressed gas line is supplied such that the pressure in the pressure-regulated section is substantially kept at a constant value. The invention additionally relates to a corresponding device.

The present invention reduces the effects from variations in the outside air pressure on particle number counting, and is provided with an exhaust gas processing unit that performs predetermined processing on exhaust gas, a particle number counting unit that counts a number of particles contained in exhaust gas that has passed through the exhaust gas processing unit, a fluid resistance element that is provided downstream from the particle number counting unit, a suction pump that is provided downstream from the fluid resistance element, a gas supply path that is connected to a flow path between the fluid resistance element and the suction pump, and supplies gas to a downstream side of the fluid resistance element, and a flow rate adjustment unit that is provided on the gas supply path, and adjusts a flow rate of the gas that is supplied to the downstream side of the fluid resistance element.

Systems, apparatuses and methods for systematically executing a diagnosis and fault isolation of a failure condition for an engine during a cranking test of the engine. Examples of the failure condition include, but are not limited to, cylinder-by-cylinder compression conditions, excessive blow-by conditions, valve failures, leaks, and/or obstructions of the intake, exhausts, crankcase ventilation, and/or exhaust gas recirculation systems.

Methods and systems are provided for an EGR system reverse hose diagnostic. In one example, a method includes executing the reverse hose diagnostic in response to an EGR flowrate exceeding a threshold flow rate.

An engine system includes a delta pressure sensor configured to sense a pressure difference across an engine exhaust handling component and an electronic control system configured to determine a cold sensor condition permitting icing of the delta pressure sensor, determine a sensed pressure deviation condition indicative of deviation of the pressure difference sensed by the delta pressure sensor from a deviation limit, dynamically model a sensor heat transfer condition indicative of heating or cooling of the delta pressure sensor, determine that the sensor heat transfer condition is indicative of insufficient heating of the delta pressure sensor to mitigate icing of the delta pressure sensor, and determine an icing condition of the delta pressure sensor.

Methods and systems are provided for an EGR system reverse hose diagnostic. In one example, a method includes executing the reverse hose diagnostic in response to an EGR flowrate exceeding a threshold flow rate.

A diagnostic system and method that (a) that uses models indicative of both successful firing and skips to determine if cylinders of a skip fire controlled internal combustion engine have successfully fired or successfully skipped and (b) uses filtered exhaust gas pressure readings for detecting faults associated with EGR systems and/or turbocharger systems.

A diagnostic system and method that (a) that uses models indicative of both successful firing and skips to determine if cylinders of a skip fire controlled internal combustion engine have successfully fired or successfully skipped and (b) uses filtered exhaust gas pressure readings for detecting faults associated with EGR systems and/or turbocharger systems.

Methods and systems are provided for diagnostics of a cylinder valve actuation mechanism in a variable displacement engine (VDE). In one example, during an engine-off condition, the engine may be rotated unfueled, via a starter motor, and a reference exhaust air flow may be estimated. One or more deactivatable engine cylinders may then be deactivated and degradation of the cylinder valve actuation mechanism may be indicated based on a difference between the exhaust air flow following the cylinder deactivation and the reference exhaust air flow.