When the geometric compression ratio of an engine body is set to 13:1 or more and the engine body operates in a preset high load region, the effective compression ratio of the engine body is set to 12:1 or more with a difference from the geometric compression ratio being within 2, a gas to be introduced into a combustion chamber is supercharged by a supercharging system, fuel is injected at least in a compression stroke by an injector, and after the fuel injection is finished, an air-fuel mixture in the combustion chamber is ignited by an ignition device before the compression top dead center and is thus burned by flame propagation in the engine body, and then the unburned air-fuel mixture is burned by compression ignition.

Methods and apparatuses for calibration and control of various engine subsystems using a target value approach. Under the target value approach, the control of each engine subsystem is separated or decoupled to include a set of target values, or a reference value set. A subsystem has a corresponding target determiner, which provides a target value set, or reference value set, in response to a basis variable set and optionally an overall subsystem target. The basis variable set includes parameters selected to robustly characterize the variables that affect the operation of the particular subsystem. The target determiner is optionally calibrated to provide a reference value set within specifications of the subsystem. A physical subsystem controller operates in response to the reference value set.

Methods and apparatuses for calibration and control of various engine subsystems using a target value approach. Under the target value approach, the control of each engine subsystem is separated or decoupled to include a set of target values, or a reference value set. A subsystem has a corresponding target determiner, which provides a target value set, or reference value set, in response to a basis variable set and optionally an overall subsystem target. The basis variable set includes parameters selected to robustly characterize the variables that affect the operation of the particular subsystem. The target determiner is optionally calibrated to provide a reference value set within specifications of the subsystem. A physical subsystem controller operates in response to the reference value set.

A plant control system comprises a feedback controller 5 configured to determine a control input of a plant 6 so that one control output of the plant approaches a target value, a provisional target value calculating part 2 configured to calculate a provisional target value based on a predetermined parameter of the plant, and a reference governor 3 configured to perform a minimum value search of an object function by updating a corrected target value to thereby derive the target value from the provisional target value. The reference governor is configured to update the corrected target value only between r0.5R.sub.r and r. R.sub.r is a value of a partial differential for the corrected target value w of the object function when the corrected target value w is the provisional target value r.

A control system includes an electronic control unit including a feedback controller and a reference governor. The feedback controller is configured to determine a value of control input such that a value of control output approximates a target value. The reference governor is configured to calculate, with a prediction model, a predicted maximum value of an overshoot amount of the control output that overshoots from the target value. The prediction model is derived assuming that an n-th delay (n is a natural number) occurs in a response of the control output. The reference governor is configured to calculate the target value by correcting the provisional target value of the control output based on the predicted maximum value so as to increase a degree of satisfaction of a constraint condition with regard to the control output.

Methods and systems are provided for detecting cylinder-to-cylinder air-fuel ratio (AFR) imbalance in engine cylinders. In one example, a method may include detecting an AFR imbalance of an engine cylinder based on an individual crankshaft acceleration of the cylinder relative to a mean crankshaft acceleration produced by all cylinders of the engine, and correcting a fuel amount of the cylinder via a fuel multiplier value, the fuel multiplier value selected from a plurality of fuel multiplier values based on an imbalance source. In this way, the AFR imbalance may be accurately detected and correcting using existing engine system sensors.

Methods and systems are provided for a comprex charger. In one example, a comprex charger is integrally arranged with an electric machine and shares a cooling arrangement therewith.

Methods and systems are provided for estimation of a road roughness index (RRI) and adjusting vehicle operation based on the metric. In one example, a method may include estimating the RRI as a function of a pitch energy and a roll energy of the vehicle travelling on the road. In response to the RRI being higher than a threshold, engine operation such as EGR flow rate may be adjusted.

A device for controlling the amount of fluid fed to the intake of a supercharged internal-combustion engine includes at least one turbocharger with a compression stage including at least one compressor with an intake for the fluid to be compressed, an expansion stage with at least one turbine having at least one exhaust gas inlet and expanded exhaust gas outlet, a transfer line for carrying the compressed fluid from the compressor outlet to the at least one turbine inlet with throttling means for controlling the compressed fluid transfer to the turbine, and an exhaust gas recirculation line between exhaust gas outlet of turbine and intake of compressor.

Provided is a technique capable of suppressing the amount of fuel adhering to a wall surface of a cylinder in an engine whose wall surface temperature varies every cycle. An internal combustion engine control device that controls an internal combustion engine, which injects fuel into a cylinder and generates combustion by ignition, includes: a wall surface temperature calculation unit that calculates a wall surface temperature of the cylinder based on a pressure in the cylinder; and a combustion control unit that controls the combustion of the internal combustion engine based on the calculated wall surface temperature.