An in-cylinder pressure sensor detecting in-cylinder pressure is provided. A first crank angle and a second crank angle in the adiabatic compression stroke are set using an in-cylinder-pressure-maximum crank angle as a baseline, and an absolute pressure correction value is calculated using the in-cylinder pressure and in-cylinder volume at each of these crank angles. A crank angle advanced from the in-cylinder-pressure-maximum crank angle is set as the second crank angle in a manner so as to be a timing in the adiabatic compression stroke on the retard side with respect to the spark timing, and is used for the absolute pressure correction.

The embodiments relate to a method and to a device for operating a system including a generator and an internal combustion engine driving the generator, wherein a rotational speed of the generator is controlled by a rotational speed controller. In the method, the rotational speed controller outputs a target torque as manipulated variable, and an additional torque is imposed on the target torque, wherein the additional torque is calculated or is determined based on a measured value picked up from the system.

Disclosed herein is a method of predicting engine knocking, which includes calculating initial pressure in cylinder based on operating data and pressure in intake manifold measured using manifold absolute pressure sensor, calculating pressure at spark timing in the cylinder by interpreting compression process as polytropic process based on the calculated initial pressure in the cylinder, calculating heat release rate for individual operating conditions based on the calculated pressure in the cylinder at spark timing, calculating pressure change in the cylinder based on the calculated heat release rate, calculating unburned gas temperature in adiabatic compression process based on the calculated pressure change in the cylinder, and determining whether knock occurs by calculating ignition delay based on the calculated unburned gas temperature and calculating unburned gas mass fraction at crank angle at the end of the ignition delay.

Provided is an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes an injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Ignition timing of the preceding ignition is set to be more retarded when an in-cylinder pressure specified by an in-cylinder pressure specification section is high than when the in-cylinder pressure is low.

An engine torque estimating apparatus having a processor and a memory accessed by the processor. The processor performs a torque estimating that calculates time series data of an estimated indicated torque, based on a crank angle having been extracted from an output of a crank angle sensor of an engine including a plurality of cylinders; an estimated indicated torque-related value extracting that extracts an estimated indicated torque-related value, for each of the cylinders, from the time series data of the estimated indicated torque, for each of the cylinders; and average indicated torque correct value acquiring that converts, for each of the cylinders, the estimated indicated torque-related value into an average indicated torque correct value having been calculated based on a cylinder internal state of the engine in correspondence to the estimated indicated torque-related value.

Various embodiments of the present disclosure are directed towards free-piston combustion engines. As described herein, a method and system are provided for displacing a free-piston assembly to achieve a desired engine performance by repeatedly determining position-force trajectories over the course of a propagation path and effecting the displacement of the free-piston assembly based, at least in part, on the position-force trajectory. In a dual-piston assembly free-piston engine, synchronization of the two piston assemblies is provided.

Various embodiments of the present disclosure are directed towards free-piston combustion engines. As described herein, a method and system are provided for displacing a free-piston assembly to achieve a desired engine performance by repeatedly determining position-force trajectories over the course of a propagation path and effecting the displacement of the free-piston assembly based, at least in part, on the position-force trajectory. In a dual-piston assembly free-piston engine, synchronization of the two piston assemblies is provided.

Systems, apparatus, and methods are disclosed that include an internal combustion engine having a plurality of cylinders and controlling the intake manifold pressure during early intake valve opening to reduce or prevent oil consumption.

Systems and methods for estimating an engine event location are disclosed herein. In one embodiment, a control system is configured to receive feedback from at least one vibration sensor coupled to a reciprocating engine, estimate an engine parameter based at least on the feedback and an Empirical Transform Function (ETF), estimate a location of an engine event based on the engine parameter, and adjust operation of the reciprocating engine based at least on the location of the engine event.

A combustion control system for an engine of a vehicle includes an ion sensing system configured to generate an ion current signal indicative of a measured current across electrodes of a spark plug associated with a cylinder of the engine and a controller configured to monitor for peaks in the ion current signal and, upon detecting at least a first peak and a second peak in the ion current signal, estimate a location of peak pressure (LPP) based on the detected second peak in the ion current signal, estimate an angle (CA50) of a crankshaft of the engine at which approximately 50% of the heat generated during combustion in the cylinder of the engine is released, and control combustion phasing of the engine based on the estimated CA50 angle.