The present invention provides for predicting peak cylinder temperatures above which knock in an engine may become more frequent and then provides one or more actuation approaches to reduce the knock of the engine while maintaining engine performance. The actuation approaches of the present invention include one or more of direct injection, engine gas recirculation, and spark retarding, where the application of one or more the actuation approaches is determined based upon using operational and engine characteristic inputs as well as modeling and estimation values as inputs in a feedforward control methodology.

An engine control system includes an engine calibration module that sets fuel injection timing based on one of N cetane number (CN) values, wherein N is an integer greater than one. A combustion noise module generates a combustion noise signal based on cylinder pressure in a compression ignition (CI) engine during combustion. A fuel quality determination module compares the combustion noise signal to N predetermined combustion noise levels corresponding to the N CN values, and that selects the one of the N CN values based on the comparison.

A microcomputer which constitutes an ECU transmits a start/stop signal and a crank angle signal to an analog input circuit. The analog input circuit is activated when the start/stop signal is received. The A/D converter converts a sensor signal into a digital signal. The digital processor detects a peak value of the digital signal. A counter restarts a counting operation when the crank angle signal is received. A data register sends a detected data of the peak value as a specified information adding by a count value and an information of the crank angle signal to the microcomputer. The microcomputer acquires the crank angle of the specified information by computing the crank angle from the detected data.

In a control device for an internal combustion engine in which internal EGR and external EGR are conducted, an ideal in-cylinder gas amount and an ideal in-cylinder gas temperature in an ideal state in which neither of EGR gas recirculates into a cylinder are calculated (steps 1 and 2). A mixed gas amount of intake air and the external EGR gas present on a downstream side of a throttle valve is calculated, based on a rotation speed of the internal combustion engine and intake air pressure (step 21) to detect a mixed gas temperature. An actual in-cylinder gas temperature and amount and an EGR ratio are calculated, based on the ideal in-cylinder gas amount, the ideal in-cylinder gas temperature, the mixed gas amount, and the mixed gas temperature (steps 24, 4, and 5), and an internal combustion engine is controlled based on the EGR ratio.

Methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system may include first and second fuel systems to deliver liquid and gaseous fuels, respectively, to at least one cylinder of the engine, and a controller. The controller may be configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder to compression ignite the liquid fuel and combust the gaseous fuel in the at least one cylinder, and retard an injection timing of the injection of the liquid fuel based on a measured parameter associated with auto-ignition of end gases subsequent to the compression-ignition of the liquid fuel. In some examples, the controller may further be configured to adjust an amount of the gaseous fuel relative to an amount of the liquid fuel based on the measured parameter.

Methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system may include first and second fuel systems to deliver liquid and gaseous fuels, respectively, to at least one cylinder of the engine, and a controller. The controller may be configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder to compression ignite the liquid fuel and combust the gaseous fuel in the at least one cylinder, and retard an injection timing of the injection of the liquid fuel based on a measured parameter associated with auto-ignition of end gases subsequent to the compression-ignition of the liquid fuel. In some examples, the controller may further be configured to adjust an amount of the gaseous fuel relative to an amount of the liquid fuel based on the measured parameter.

Methods and systems are provided for operating a variable displacement engine that includes a knock control system. Engine background noise levels for detecting engine knock may be the basis for determining whether or not the engine is operating in a cylinder deactivation mode. Further, select variable engine displacement modes may be avoided so that engine background noise level changes may be reduced to improve engine knock detection.

An internal combustion engine includes an internal combustion engine main body including a plurality of cylinders, a knock sensor provided on each of the plurality of cylinders, a control board including an amplification circuit, and a plurality of cables differing in length and each connecting the knock sensor and the control board. The amplification circuit includes, for each of the plurality of cables, a first charge amplifier connected to a first output terminal of the knock sensor via one of the plurality of cables, a second charge amplifier connected to a second output terminal of the knock sensor via one of the plurality of cables, and a differential amplifier configured to take an output of the first charge amplifier and an output of the second charge amplifier as input.

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.

An apparatus of controlling a vehicle and a method thereof are provided. The operating region of an engine is operated with theoretical air-fuel ratio. The apparatus includes a supercharger that supplies compressed air to a the combustion chamber of the engine and a spark plug that ignites mixed air supplied to the combustion chamber. An intake valve selectively opens and closes the combustion chamber for inflowing the mixed air therein. A variable valve apparatus adjusts an opening timing and closing timing of the intake valve and a controller adjusts an ignition timing of the spark plug and the closing timing of the intake valve through the variable valve apparatus based on the operating region of the engine.