Disclosed is a method for determining the engine torque delivered by a multi-cylinder engine, including the following steps: determining the angular velocity of the crankshaft and measuring the cylinder pressure over an angular window of combustion in a first cylinder fitted with a cylinder pressure sensor; calculating the value of the engine torque (TQI.sub.ref) in this window; determining a current transfer function for the learning of the torque, so as to estimate the torque TQI.sub.mdl(cyl)) in a second cylinder not fitted with a cylinder pressure sensor, from the product of: the engine torque calculated over the angular window of the first cylinder, a ratio between: the angular velocity of the crankshaft over an angular window of combustion of the second cylinder, and the angular velocity of the crankshaft over the window of combustion of the first cylinder.

A process to adjust the ignition timing of an air-fuel mixture in a combustion chamber of an internal combustion engine, the process comprises determining a first quantity indicative of a pressure of the mixture for a cycle of the engine, determining a second quantity indicative of a speed of the engine, determining a third quantity indicative of a first temperature of a conditioning fluid, providing a heat exchange mathematical model for the combustion chamber, which maps the three quantities from the first to the third one onto a fourth quantity indicative of a second temperature of a wall portion around the combustion chamber, estimating the fourth quantity by means of the three determined quantities and by means of the mathematical model, and adjusting the ignition timing as a function of the fourth estimated quantity.

A controller for an internal combustion engine includes a detector and a processor. The detector detects a combustion condition of a gas in a cylinder of the internal combustion engine. The processor is configured to calculate a target combustion condition. The processor is configured to calculate an ignition timing such that the combustion condition detected by the detector becomes equal to the target combustion condition via a feedback control with a gain. The processor is configured to calculate a fuel ratio in the gas in the cylinder. The processor is configured to determine the gain so as to increase as the fuel ratio decreases.

A controller for an internal combustion engine includes a detector and a processor. The detector detects a combustion condition of a gas in a cylinder of the internal combustion engine. The processor is configured to calculate a fuel ratio in the gas in the cylinder. The processor is configured to calculate a target combustion condition according to the fuel ratio. The processor is configured to calculate an ignition timing such that the combustion condition detected by the detector becomes equal to the target combustion condition.

A system for a vehicle includes a filtering module and an indicated work module. The filtering module generates engine speeds based on positions of teeth of a toothed wheel that rotates with a crankshaft and based on a crankshaft position signal generated by a crankshaft position sensor. The crankshaft position sensor generates the crankshaft position signal based on rotation of the toothed wheel. The indicated work module generates an indicated work for a combustion cycle of a cylinder of an engine based on squares of first and second ones of the engine speeds and outputs the indicated work.

A method for determining the recycled air flow rate and oxygen quantity at the inlet of an internal combustion engine cylinder. The method involves measuring pressure in each cylinder during a compression phase and calculating the mass of gas in each cylinder based on the measured pressure, volume and temperature variation for an angular variation of the crankshaft, heat capacity, and heat losses. The method further involves determining the mass of gas in all cylinders over a full combustion cycle as well as in the recycled exhaust.

A method for controlling an internal combustion engine operating on at least partly gaseous fuel is disclosed. The method may include providing a desired burn rate profile corresponding to a desired operation of the internal combustion engine. The method may further include selecting first operating parameters such that an operation of the internal combustion engine with a first gas composition produces a first burn rate profile that corresponds to the desired burn rate profile. The method may also include operating the internal combustion engine with the first operating parameters using a second gas composition. The method may include determining that the second burn rate profile differs from the desired burn rate profile. In addition, the method may include adjusting an operating parameter from among the first operating parameters of the internal combustion engine to approach the desired burn rate profile.

A system includes an internal combustion engine having a number of cylinders, with at least one of the cylinder(s) being a primary EGR cylinder that is dedicated to provided EGR flow during at least some operating conditions. A controller is structured to control combustion conditions in the cylinders in response to one or more operating conditions associated with the engine.

A method for operating an internal combustion engine, the method including the steps of: (a) actuating an injector to introduce a pre-injection amount of a fuel into a combustion chamber of the internal combustion engine; (b) determining, for an operating cycle of the combustion chamber in which the injector was actuated in the step (a), a pressure gradient characteristic value which is characteristic of a combustion chamber pressure gradient in the combustion chamber; (c) repeating the steps (a) and (b) a plurality of times; (d) determining a skew of a distribution of a plurality of pressure gradient characteristic values determined in the step (c); and (e) changing or maintaining an actuation of the injector depending on the skew determined in the step (d).

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.