Methods and systems are provided for accurately estimating intake aircharge based on the output of an intake oxygen sensor while flowing EGR, purge, or PCV hydrocarbons to the engine. The unadjusted aircharge estimate is used for engine fuel control while the hydrocarbon adjusted aircharge estimate is used for engine torque control. A controller is configured to sample the oxygen sensor at even increments in a time domain, stamp the sampled data in a crank angle domain, store the sampled data in a buffer, and then select one or more data samples corresponding to a last firing period from the buffer for estimating the intake aircharge.

A method for operating a compression ignition engine includes forming a combustible mixture by mixing generally homogeneously a first fuel and air and introducing this mixture into the at least one cylinder, compressing the combustible mixture with the piston in a compression stroke, injecting a second fuel to the combustible mixture at an injection-time of the second fuel during the compression stroke but before start of combustion, and continuing the compression stroke until combustion starts at those locations in the at least one cylinder where concentration of the second fuel is highest and/or the temperature of the mixture is the highest. Emission of the cylinder and/or mechanical stress of the cylinder caused by the combustion are monitored, and if emissions and/or mechanical stress are above respective predetermined thresholds, individually for the cylinder, the amount and/or the timing of the second fuel injected, and/or temperature of the cylinder charge is changed.

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.

A system according to the principles of the present disclosure includes a first burn duration module and a spark control module. The first burn duration module determines a first duration of at least a portion of a fuel burn within a cylinder of an engine from a first time when a first predetermined percentage of a mass of fuel within the cylinder is burned to a second time when a second predetermined percentage of the fuel mass is burned. The spark control module controls a spark plug to adjust spark timing of the cylinder based on the first burn duration.

An engine control system of a vehicle includes an estimation module and an actuator module. The estimation module estimates a crankshaft angle where 50 percent of a mass of fuel is burned during a combustion event based on: a combustion speed when a crankshaft of an engine is at a predetermined position during the combustion event; an engine speed; a mass of air per cylinder (APC); a spark timing; and a predetermined spark timing. The actuator module controls an engine actuator based on the crankshaft angle where 50 percent of the mass of fuel is burned during the combustion event.

The control apparatus for a compression ignition type engine includes a plurality of cylinder inner pressure sensors that detect pressure in each cylinder, and a combustion control unit. The combustion control unit corrects a target fuel injection amount of each cylinder by an injector based on a deviation between a predicted combustion period that is a period from an ignition timing by an ignition plug to a predetermined mass combustion timing and that is obtained based on a preset combustion model, and an actual combustion period that is a period from the ignition timing by the ignition plug to an actual combustion timing and that is obtained based on cylinder inner pressure, such that the period from the ignition timing by the ignition plug to the predetermined mass combustion timing, which is the timing when fuel having a predetermined mass ratio combusts, is equalized in each cylinder.

A method for monitoring an engine cylinder in an internal combustion engine includes, for each engine cycle, detection of the ionisation current generated in the cylinder in a predetermined time interval of a combustion cycle, generation of a signal representing the ionisation current and comparing a maximum value of the signal with a threshold value. Successively, the value of one or more parameters associated with the signal can be changed with respect to an equal number of corresponding reference values when the maximum value of the signal exceeds the threshold value, to reduce the maximum value of the signal in the time interval of a successive combustion cycle. The presence of water in the cylinder can be determined when the maximum value of the signal exceeds the threshold value for a predetermined first number of combustion cycles occurring within a predetermined period of time.

A method to control the combustion of an internal combustion engine, which comprises determining a combustion model, which provides a spark advance depending on an objective value of the rate of water to be injected, on the rotation speed, on the intake efficiency and on an open-loop contribution of a combustion index; calculating a first closed-loop contribution of the spark advance depending on the combustion index; calculating a second closed-loop contribution of the spark advance depending on a quantity indicating the knocking energy; and calculating the objective value of the spark advance angle to be operated through the sum of the spark advance value provided by the combustion model and of the first closed-loop contribution or, alternatively, of the second closed-loop contribution.

Provided is a fuel-reforming device comprising: an ammonia tank (4); a reformer (5) for reforming ammonia and generating high-concentration hydrogen gas having a hydrogen content of at least 99%; a mixing tank (7) for mixing ammonia and hydrogen for temporary storage; and a control means (10) for controlling the respective supply amounts of ammonia and high-concentration hydrogen gas that are supplied to the mixing tank (7). The control means (10) calculates the combustion rate coefficient C of mixed gas with respect to a reference fuel on the basis of equation (1). Equation (1): S.sub.0=S.sub.H×C+S.sub.A×(1−C). In equation (1), S.sub.0 is the combustion rate of the reference fuel, S.sub.H is the combustion rate of hydrogen, S.sub.A is the combustion rate of ammonia, and C is the combustion rate coefficient of mixed gas. In addition, on the basis of equation (2), the control means (10) determines the volume fractions of ammonia and hydrogen that are supplied to the mixing tank. Equation (2): C=1−exp(−A×M.sub.B). In equation (2), M is the volume fraction of hydrogen in mixed gas, and A and B are constants.

A controller for a dedicated exhaust gas recirculation (D-EGR) engine is disclosed. The controller may receive a plurality of cylinder pressure signals, each of which is associated with a respective cylinder in a plurality of cylinders of the D-EGR engine. The plurality of cylinders includes at least one donor cylinder and a set of non-donor cylinders. The controller may receive a crankshaft angle signal associated with a crankshaft of the D-EGR engine. The controller may selectively adjust ignition timing of a cylinder, of the plurality of cylinders, based on the crankshaft angle signal and a cylinder pressure signal, of the plurality of cylinder pressure signals, associated with the cylinder; or a fuel rate of the at least one donor cylinder based on the crankshaft angle signal and a set of cylinder pressure signals, of the plurality of cylinder pressure signals, associated with the set of non-donor cylinders.