A controller for a diesel engine has a fuel injector which injects a fuel into a cylinder. The controller has a middle-combustion time computing portion which computes a middle-combustion time period that has elapsed from the fuel is injected until a half of the fuel has combusted, based on a detection value of a cylinder pressure sensor. Further, the controller has a fuel component computing portion which computes a ratio of a carbon quantity relative to a hydrogen quantity contained in the fuel based on the middle-combustion time period.

A fuel estimation apparatus includes a combustion characteristic acquisition portion and a mixing ratio estimation portion. The combustion characteristic acquisition portion acquiring a combustion characteristic value indicating a physical amount relating to a combustion of an internal combustion engine acquires the combustion characteristic values of the combustions executed in different combustion conditions. The mixing ratio estimation portion estimates the mixing ratios of various components included in a fuel, based on the combustion characteristic values acquired by the combustion characteristic acquisition portion.

A combustion system controller controls an operation of a combustion system including an internal combustion engine. The combustion system controller includes a mixing ratio acquisition portion and a control portion. The mixing ratio acquisition portion acquires the mixing ratios of various components included in a fuel. The control portion controls the operation of the combustion system based on the mixing ratios acquired by the mixing ratio acquisition portion.

A controller for an internal combustion engine is configured, when the speed of combustion of a fuel in a cylinder changes as the property of the fuel injected from a fuel injection valve changes, to change a combustion limit excess air ratio that is a target value of a fuel injection amount feedforward control according to a first relationship that the combustion limit excess air ratio increases as the speed of combustion of the fuel in the cylinder increases. The controller is also configured, when the speed of combustion of the fuel in the cylinder changes as the property of the fuel injected from the fuel injection valve changes, to change the value of a combustion limit combustion speed parameter that is the target value of a fuel injection amount feedback control according to a second relationship that the speed of combustion of the fuel in the cylinder corresponding to a combustion limit increases as the speed of combustion of the fuel in the cylinder increases.

A control device for an internal combustion engine is provided. The internal combustion engine includes a cylinder, an in-cylinder pressure sensor, a fuel injection valve, and an alcohol concentration sensor. The control device includes an electronic control unit. The electronic control unit is configured to: carry out learning of fuel properties with the fuel injected from the fuel injection valve as a target; calculate a combustion speed parameter, showing a combustion speed, within the cylinder, of the fuel that is a learning target of the fuel properties, on a basis of the in-cylinder pressure; and determine that water is included in the fuel when the capacitance of the fuel detected by the alcohol concentration sensor is larger than a preset first threshold, and when the combustion speed of the fuel within the cylinder is smaller than a preset second threshold.

The invention relates to a method for operating an internal combustion engine (1) provided with at least one working cylinder (3a-3d) each with an associated auxiliary cylinder (5a-5d), which engine (1) is operable in spark ignition and compression ignition modes. Each working cylinder (3a-3d) comprises a working piston (7a-7a) connected to a first crankshaft (9), and each auxiliary cylinder (5a-5d) comprises an auxiliary piston (10a-10d) connected to a second crankshaft (12). The first crankshaft (9) is connected to the second crankshaft (12) to drive the second crankshaft (12) at half the rotational speed of the first crankshaft (9). A device for controlling the phase angle is arranged between the first and second crankshafts. The method involves controlling the phase shift device in order to retain residual exhaust gas and increase the compression ratio. A current combustion phasing timing is determined, and the combustion phasing timing is corrected by increasing or decreasing the phase angle to achieve a desired combustion phasing timing.

Disclosed is a combustion system design method based on a target heat release rate, which belongs to the technical field of diesel engine combustion chamber design. The method includes: obtaining an ideal heat release rate based on Sabathe-Miller cycle; simulating the ideal heat release rate based on a double-Wiebe function and obtaining the target heat release rate; constructing a mapping relation among the heat release rate, piston geometric parameters and fuel injection parameters, which includes target start of combustion being an function of fuel injection timing and ignition delay, premixed combustion parameters being functions of throat radius, injection pressure and nozzle diameter, and diffusion combustion being a function of piston pit depth; solving target piston geometric parameters and target fuel injection parameters based on the mapping relation; and then designing a combustion system. The method does not depend on experience and multi-scheme design, greatly shortens the combustion system design.

To provide a controller for internal combustion engine which can suppress deterioration of the detection accuracy of the combustion state due to influence of the external disturbance component, when detecting a combustion state based on angle detection information by the crank angle sensor. A controller for internal combustion engine calculates a shaft torque in unburning; calculates an external load torque based on the shaft torque in unburning and the actual shaft torque in the vicinity of the top dead center; and in an integration crank angle interval which is set corresponding to a combustion period, calculates a subtraction value by subtracting the external load torque from the shaft torque in unburning, calculates a division value by dividing the subtraction value by the inertia moment, and calculates a combustion state index by integrating a value obtained by subtracting the division value from the crank angle acceleration.

An action of injection of the main injection fuel (QM) from the fuel injector (3) is started within a range of crank angle from 10 degree before the compression top dead center to 10 degree after the compression top dead center. A smaller amount of the auxiliary injection fuel (QN) than the main injection fuel (QM) is made to be injected from the fuel injector (3) before the main injection fuel (QM) so as to make the auxiliary injection fuel (QN) ignite by the premixed charge compression ignition. The injection timing of the auxiliary injection fuel (QN) is controlled to a timing whereby a heat generated by the premixed charge compression ignition of the auxiliary injection fuel (QN) causes the premixed charge compression ignition of the main injection fuel (QM) after the start of injection of the main injection fuel (QM).

A system for and a method of knock detection and control for an engine utilizes a knock sensor configured to generate a knock signal indicative of a vibration of the engine caused by abnormal combustion. A controller is configured to receive the knock signal, determine, with respect to a crank angle of the engine, distinct monitoring windows for low speed pre-ignition (LSPI) knock and spark knock, respectively, based on (i) spark timing and (ii) an appropriate mass fraction burn (MFB) location, monitor the knock signal using the distinct monitoring windows, detect one of LSPI knock and spark knock based on the monitoring, and control the engine to mitigate the detected LSPI knock or spark knock.