A system and method monitor operation of a compressor, determine whether the operation of the compressor is outside of a designated range of values, and, responsive to determining that the operation of the compressor is outside of the designated range of values, one or more of (a) prevent communication of a signal to a system controller that controls operation of the compressor, (b) direct a gas from a reservoir to a pressure sensor used by the system controller to determine a gas pressure generated by the compressor, and/or (c) communicate the signal to the system controller that controls operation of the compressor.

Systems and methods are provided for diagnosing cylinders. In one example, a system includes an engine having a plurality of cylinders coupled to a crankshaft, a crankshaft speed sensor, and a controller. The controller is configured to receive a first output from the crankshaft speed sensor during nominal engine operation, receive a second output from the crankshaft speed sensor during engine operation where a fueling disturbance is introduced to a cylinder of the plurality of cylinders, indicate that the cylinder is unhealthy responsive to a difference between the first output and the second output being less than a threshold difference, and adjust one or more operating parameters of the engine in response to the indication.

A method of monitoring the usage of an internal combustion engine is provided. The method comprises performing an engine monitoring routine using a local monitoring device directly attached to an internal combustion engine. The engine monitoring routine includes generating a plurality of data points representative of the crankcase pressure of the internal combustion engine using a pressure sensor of the local monitoring device, processing the generated data points to determine a first value representative of a firing frequency of the internal combustion engine, generating an aggregated summary of the internal combustion engine usage based on the first value, and transmitting identification data for the local monitoring device and the aggregated summary from the local monitoring device to a remote application. The remote application processes the transmitted aggregated summary based on the transmitted identification data to determine engine speed usage data for the internal combustion engine.

The invention relates to a device and a processing method for a camshaft sensor (1) of the type comprising a toothed camshaft wheel (2) and an opposite sensing element (3) able to detect a tooth front, comprising the following steps: detection of a new tooth front (k) by said sensing element; calculation of a rotational speed (Wk) of the camshaft wheel (2) for the new tooth front (k); comparison with the rotational speed (Wk−1) of the camshaft wheel for the preceding tooth front (k−1) detected by said sensing element; if the variation in the rotational speed (Wk) of the camshaft wheel (2) between the new tooth front (k) and the preceding tooth front (k−1) is low, the new tooth front (k) is validated, otherwise the new tooth front (k) is rejected.

A CPU stops combustion control of Cylinder #1 in order to perform a regeneration process of a GPF and performs a regeneration process of causing an air-fuel ratio of an air-fuel mixture in Cylinders #2 to #4 to be richer. When it is determined that a misfire has occurred because a misfire rate when the regeneration process is not being performed is equal to or greater than a predetermined value, the CPU determines that an internal combustion engine has returned to a normal state based on the premise that the misfire rate when the regeneration process is not being performed decreases.

Provided is an internal combustion engine control device that is capable of accurately estimating a stable combustion state at low cost. An internal combustion engine control device according to one aspect of the present invention includes: a rotational speed calculation unit 122a that calculates a time-series value of a crank rotational speed of an internal combustion engine; a rotational, speed phase calculation unit 122b that calculates a phase of the crank rotational speed from the time-series value of the crank rotational speed calculated by the rotational speed calculation unit; and a cycle variation calculation unit 122c that calculates the magnitude of variation between cycles of the phase of the crank rotational speed calculated by the rotational speed phase calculation unit.

Provided is an internal combustion engine control device that is capable of accurately estimating a stable combustion state at low cost. An internal combustion engine control device according to one aspect of the present invention includes: a rotational speed calculation unit 122a that calculates a time-series value of a crank rotational speed of an internal combustion engine; a rotational, speed phase calculation unit 122b that calculates a phase of the crank rotational speed from the time-series value of the crank rotational speed calculated by the rotational speed calculation unit; and a cycle variation calculation unit 122c that calculates the magnitude of variation between cycles of the phase of the crank rotational speed calculated by the rotational speed phase calculation unit.

A straddled vehicle engine unit including an internal combustion engine and a misfire detection device. The internal combustion engine has a crankshaft, and a crank angle signal output unit that periodically outputs a crank angle signal in accordance with rotation of the crankshaft. The internal combustion engine is configured to repeat at least two kinds of strokes on a cycle of every 720-degree rotation of the crankshaft. The misfire detection device includes a crankshaft rotation speed fluctuation physical quantity acquisition unit configured to acquire a physical quantity related to an amount of fluctuation in a rotation speed of the crankshaft in one kind of stroke, out of the at least two kinds of strokes, based on the crank angle signal from the crank angle signal output unit, and a misfire determination unit configured to perform a misfire determination in response to each acquisition of the crankshaft rotation speed fluctuation physical quantity.

A system includes a reciprocating piston engine configured to output torque to drive a load. The system includes an engine speed sensor operatively coupled with the engine and configured to output an engine speed signal. The system includes an electronic control system operatively coupled with the powertrain. The electronic control system is configured to determine an engine acceleration in response to the engine speed signal, and detect a misfire of the engine in response to the engine acceleration.

To accurately estimate a combustion state even in a case where the combustion state in a combustion chamber greatly changes. According to an aspect of the present invention, an internal combustion engine control device 12 includes a rotational speed calculation unit 122a that calculates a crank rotational speed of an internal combustion engine, an extreme value timing calculation unit 122b that calculates an extreme value timing at which the crank rotational speed calculated by the rotational speed calculation unit 122a becomes an extreme value, a combustion-state-calculation-means selection unit 122c that selects combustion state calculation means for calculating a combustion state in a combustion chamber based on an operation state of the internal combustion engine, and a combustion state estimation unit 122d that estimates the combustion state in the combustion chamber from the extreme value timing of the crank rotational speed by using the combustion state calculation means selected by the combustion-state-calculation-means selection unit 122c.