According to the invention, a diagnostic system is provided for diagnosing a misfire condition is provided of individual engine cylinders in a turbocharged diesel engine having at least a first and a second cylinder associated with a common exhaust path. The system comprises a pressure sensor in an exhaust path, for measuring a pressure value; a crankshaft position sensor, for detecting a rotational crankshaft position; and a processor unit for reading the pressure sensor and the crankshaft position sensor. The processor unit is arranged for performing acts of: sampling pressure values of the pressure sensor in the common exhaust path as a function of crankshaft angle position; attributing for each cylinder fired in succession at least two sampling values (P.sub.α, P.sub.β) for at least two successive crankshaft angle positions of a pressure pulse during a cylinder firing operation; determining a boundary for a coordinate (P.sub.α, P.sub.β) formed by a tuple of sampling values (P.sub.α, P.sub.β); diagnosing a misfire condition if the coordinate formed by said tuple of sampling values is outside the boundary.

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.

An arrangement for cylinder detection in a four-stroke internal combustion engine is disclosed. The arrangement comprises a first disc connected to a crankshaft, the first disc comprising a first mark (M11-M13) within each an interspace angle (α), and a second disc connected to a camshaft and comprising one second mark (M21-M26) per number of cylinders. The first mark (M11-M13) is arranged on a first disc, or the plurality of first marks (M11-M13) are arranged in relation to each other on the first disc, and the second marks (M21-M26) are arranged in relation to each other on the second disc such that for each interspace angle (α) the relevant first mark (M11-M13) is detectable by a first sensor and the relevant second mark (M21-M26) is detectable by a second sensor at different relative rotational positions between the first disc and the second disc.

An object is to improve scavenging performance of a pre-combustion chamber connected to a main combustion chamber via an orifice and suppress reduction in combustion performance of an internal combustion engine. This control device for an internal combustion engine including a main combustion chamber and a pre-combustion chamber having at least one orifice between the pre-combustion chamber and the main combustion chamber, includes a first control device which controls operation of an ignition coil to generate spark discharge at a spark plug, thus combusting fuel gas, and a second control device which controls operation of the ignition coil at a timing other than the timing of combusting the fuel gas, to promote scavenging of the pre-combustion chamber.

A dual-chamber onboard electrolysis system is configured to produce HHO gas for heavy duty trucking applications.

An electronic engine timing system that includes at least (1) an engine position sensor that includes a diametric magnet and two or more hall effect sensors configured and positioned to sense diametric magnet position, (2) sensor data receiving circuitry configured for receiving sensory input, including at least input from the engine position sensor; and (3) control circuitry configured to control firing of one or more cylinders of the engine at least in part by calculating one or more timing advance positions for one or more cylinders of the engine and by causing the one or more cylinders to fire according to the one or more calculated timing advance positions, the control circuitry further configured to calculate the one or more timing advance positions for the one or more cylinders separately from one another based at least in part on input from the engine position sensor.

A method for performing an on-board diagnostic function in a motor vehicle including at least one drive system, at least one operating element and at least one control unit with a processor, a control module and an on-board diagnostic function module. The method includes the steps of: activating an on-board diagnostic function in the on-board diagnostic function module; supplying a first signal profile (S1) of an operating value (CV) of the operating element to an analysis module; the analysis module analyzing the first signal profile (S1) of the operating value (CV); activating a filtering module in the event of a positive analysis result; and the filtering module filtering the first signal profile (S1) of the operating value (CV) with selected damping parameters (DP) upon activation of the filtering module in order to obtain a filtered second signal profile (S2) of the operating element.

The subject matter of this specification can be embodied in, among other things, a method performed in connection with an internal combustion engine, and the method including receiving a pressure signal from a combustion chamber pressure sensor during a first range of volumes, the first range corresponding to a portion of a compression phase, the received pressure being a first pressure, providing, based on the received pressure signal, a first pulse of fuel at a first position of the body during the compression phase, and providing, based on the received pressure signal a second pulse of fuel at a second position of the body during the compression phase.

Provided is a control device and a control method of a high-efficiency internal combustion engine capable of stabilizing combustion and suppressing NO.sub.x emissions without unnecessarily increasing a mounting load on an ECU. Therefore, the control device of the internal combustion engine for controlling the internal combustion engine includes an ignition plug that ignites an air-fuel mixture of fuel and air in the combustion chamber, a combustion pressure estimation sensor that detects a combustion pressure in the combustion chamber, and a crank angle sensor that detects a crank angle of a crankshaft. An MBT region is set based on an ignition delay period from an ignition timing of the ignition plug calculated from a detection value of the combustion pressure estimation sensor and a detection value of the crank angle sensor to a combustion start timing in the combustion chamber, and a combustion period from the combustion start timing to a set amount combustion end timing when a set amount of combustion ends. An ignition timing of the ignition plug is controlled so as to fall within the set MBT region.

A method for determining a combination of an actual intake camshaft phase position of an intake camshaft and an actual exhaust camshaft phase position of an exhaust camshaft of a production internal combustion engine having at least one cylinder, wherein the method is performed in operation of the production internal combustion engine and the relevant actual phase position of the camshafts is determined in relation to an operating point of the production internal combustion engine.