An aircraft diesel engine may be operated at a minimal fuel rate. Shaft output power of the engine may be reduced by initiating combustion during the compression stroke. Combustion may be initiated during the compression stroke by advancing fuel injection, splitting fuel injection, and/or manipulating individual injection quantities. Initiating combustion during the compression stroke may slew torque generation to the compression stroke.

A controller for an engine estimates a temperature of the exhaust gas and controls the engine according to the estimated exhaust temperature. The controller changes the air-fuel ratio to a stoichiometric air-fuel ratio or leaner. The controller calculates the progress of combustion on the basis of signals of sensors, and estimates an exhaust temperature. In the case where the air-fuel ratio is the stoichiometric air-fuel ratio, the controller estimates the exhaust temperature on the basis of the progress of the combustion, the engine temperature, and a first relationship that is at least defined between the progress of the combustion and the exhaust temperature, . In the case where the air-fuel ratio is lean, the controller estimates the exhaust temperature on the basis of the progress of the combustion, the engine temperature, and a second relationship that differs from the first relationship.

A system may include at least one processor configured to receive a fuel signal indicative of an amount of fuel supplied to a cylinder of an internal combustion engine, receive an air signal indicative of a quantity of air supplied to the cylinder, and estimate a mean effective pressure in the cylinder based at least in part on the fuel signal and the air signal. The system may estimate an exhaust gas temperature for exhaust gas entering an exhaust manifold associated with the internal combustion engine, generate a rate of temperature change value for the exhaust manifold based at least in part on the exhaust gas temperature, generate an estimated exhaust manifold temperature based at least in part on the rate of temperature change value for the exhaust manifold, and estimate an exhaust gas temperature for exhaust gas exiting the exhaust manifold and entering a turbine of a turbocharger.

Method for controlling injection of a non-combustible fluid into an internal combustion engine. The internal combustion engine may include at least one cylinder, at least one non-combustible fluid injector, at least one combustion phase determining means, and at least one control unit. The method may comprise the steps of determining the combustion phase by the combustion phase determining means, determining the amount of non-combustible fluid to be injected depending on the combustion phase.

A system and method for self-adjusting engine performance parameters in response to fuel quality variations that includes an exhaust sensor for measuring a level of carbon dioxide present in an exhaust manifold, at least one of a knock sensor and a cylinder pressure transducer for determining a location of peak pressure and a centroid, respectively, a controller in communication with the exhaust sensor and the at least one of the knock sensor and the cylinder pressure transducer, the controller correlating a methane number of the fuel used by the engine to a brake specific carbon dioxide value calculated using the level of carbon dioxide measured by the exhaust sensor and the at least one of the centroid and the location of peak pressure, and an adjusting mechanism, wherein the adjusting mechanism adjusts an engine performance parameter based on the determined methane number.

Operating a dual fuel engine system includes igniting a main charge of gaseous fuel in response to combustion of an early pilot shot of liquid fuel and production of a spark. Operating the system also includes covarying a spark timing parameter and a pilot shot delivery parameter, and reducing an error in a phasing of combustion of another main charge based on the covarying of the spark timing parameter and the pilot shot delivery parameter.

A method for engine control under an entire driving range of a vehicle based on control timing prediction implemented in the vehicle is provided, which may reduce a start angle error calculated at a calculation time prior to an operation time when actual injection and ignition is performed by grasping a tooth period change tendency for a tooth period of a current time that injector/igniter drivers of an engine control unit read from an engine position management driver and calculating a start angle of fuel injection and ignition through prediction of the tooth period to match an actual operation time. In particular, since the prediction of the tooth period to match the actual operation time is based on a change tendency of the tooth period stored up to the current time, the injection and ignition time effectively reflects an engine operation situation in which an engine RPM is changed.

Using machine learning for misfire detection in a Dynamic firing level modulation controlled internal combustion engine is described. A neural network is used to calculate expected crank acceleration from various inputs, including the dynamically defined cylinder skip fire sequence. The output of the neural network is then compared to a signal indicative of the measured crank acceleration. Based the comparison, a prediction is made if a misfire has occurred or not. In alternative embodiment, the neural network is expanded to include the measured crank acceleration as an additional input. With the latter embodiment, the neural network is arranged to directly predict misfire events.

A method for estimating a peak cylinder pressure associated with operation of an internal combustion engine may include receiving, in a cylinder combustion model, a fuel signal and an air signal. The cylinder combustion model may be configured to estimate at a first crankshaft angle, a first mass fuel burn rate and a first burned fuel-air ratio associated with combustion. The cylinder combustion model may also be configured to estimate at a second crankshaft angle, a combustion ignition delay associated with the combustion, and estimate at the second crankshaft angle, a start of combustion associated with the combustion of the fuel and the air supplied to the cylinder. The cylinder combustion model may be further configured to estimate, based at least in part on the start of combustion, a peak cylinder pressure associated with the combustion of the fuel and the air supplied to the cylinder.

A system may include at least one processor configured to receive a fuel signal indicative of an amount of fuel supplied to a cylinder of an internal combustion engine, receive an air signal indicative of a quantity of air supplied to the cylinder, and estimate a mean effective pressure in the cylinder based at least in part on the fuel signal and the air signal. The system may estimate an exhaust gas temperature for exhaust gas entering an exhaust manifold associated with the internal combustion engine, generate a rate of temperature change value for the exhaust manifold based at least in part on the exhaust gas temperature, generate an estimated exhaust manifold temperature based at least in part on the rate of temperature change value for the exhaust manifold, and estimate an exhaust gas temperature for exhaust gas exiting the exhaust manifold and entering a turbine of a turbocharger.