Methods and systems are provided for determining a dilution of recirculated gases, including blowthrough air, combusted exhaust gas, and fuel vapor, in a split exhaust engine. In one example, the dilution rate may be calculated using a steady state model based on temperature measurements from an intake region of the engine. The steady state model may be further used in combination with a feedforward model adapted to estimate engine dilution during engine transients as a correction factor.

Methods and systems for providing exhaust gas recirculation to a two stroke opposed piston diesel engine are described. In one example, high and low pressure exhaust gas recirculation systems may be activated or deactivated in response to exhaust gas hydrocarbon concentration and particulate matter flow rate from the engine. In addition, operation of the low and high pressure exhaust gas recirculation systems may be responsive to an operating state of a supercharger compressor.

Disclosed is a method for estimating the flow rate Q.sub.EGR of exhaust gases recirculated through an exhaust gas recirculation valve connecting an exhaust circuit and an intake circuit of a combustion engine, the method including the steps: of determining a difference in pressure P between the upstream and downstream sides of the valve, determining a density .sub.EGR of the recirculated exhaust gases passing through the valve, determining a corrected effective area S.sub.eff_cor of the valve, estimating the flow rate QEGR of the recirculated exhaust gases from these three parameters.

A valve control device controls an opening degree of a valve provided in an intake passage, an exhaust passage, or a passage connected one of these and includes an observed value acquisition unit, an inlet temperature acquisition unit, a target calculation unit, an equilibrium opening degree calculation unit, an observer, a correction opening degree calculation unit, an instruction opening degree calculation unit, and an output unit. The target calculation unit calculates an equilibrium state value and a target property value. The correction opening degree calculation unit calculates a correction opening degree by multiplying a gain matrix by a deviation vector including, a deviation between the equilibrium state value and the estimated state value and an integrated value of a deviation between the target property value and the estimated property value.

An object is to provide a control device for an internal combustion engine, at an inexpensive price, whereby it is possible to suppress a decrease in the exhaust gas performance of the internal combustion engine due to an environmental change or damage from aging. The present invention relates to a control device for an internal combustion engine which controls an EGR amount by adjusting an opening degree of an EGR valve (20) disposed in an EGR channel (16), the control device comprising temperature detection units (24, 26, 30), a pressure detection unit (28), a unit (48) to calculate a basic opening degree of the EGR valve, a unit (44, 56) to calculate an estimate value of at least one of an air-excess ratio or an intake oxygen concentration on the basis of detection values obtained by the temperature detection units and the pressure detection unit, a unit (46, 48) to calculate a target value of the estimate value, a unit (50) to calculate a correction factor K on the basis of the estimate air-excess ratio s and the target air-excess ratio t, a unit (52) to calculate the opening-degree command value D for the EGR valve on the basis of the basic opening degree Db and the correction coefficient K, and a unit (54) to control the EGR valve on the basis of the opening-degree command value D.

Methods and systems are provided for measuring exhaust gas recirculation (EGR) distribution among individual engine cylinders. In one example, a method may include fluidly coupling a plurality of intake runners of an engine to a vacuum pump, diverting a portion of intake charge gas from the intake runner to a gas composition sensor with the vacuum pump, measuring an oxygen concentration of the diverted intake charge portion with the gas composition sensor, and estimating an EGR concentration of the intake charge based on the measured oxygen concentration.

A gas flow control system is provided for at least one cylinder of an internal combustion of a motor vehicle. The gas flow control system includes a supply passage configured to supply gas to the cylinder and an exhaust gas passage configured to remove gas from the cylinder. A bypass passage is configured to connect the supply passage and exhaust gas passage, and a fluid control switch is selectively operable to supply gas out of the exhaust gas passage through the bypass passage into the supply passage in an exhaust gas return operating mode, and to supply gas out of the supply passage through the bypass passage into the exhaust gas passage in a post-air operating mode.

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.

The invention describes is a method (27) for controlling a coolant-conveying pump (7) in a charge gas cooling circuit (3) in order to cool a charge gas (9) for an internal combustion engine, whereby the method involves: maintaining (29) an inlet temperature (51) of the charge gas (9) in a heat exchanger (13) that is configured to exchange heat between the charge gas (9) and the coolant; ascertaining (31) a target cooling output (21) on the basis of the inlet temperature (51, T21) of the charge gas (9) and on the basis of a target outlet temperature (T22.sub.target) of the charge gas (15) coming from the heat exchanger (13); determining (33) a change (23) of the target cooling output (21) over time, and providing (35) an actuation signal (25) for the pump (7) based on the target cooling output (21) and on the change (23) of the target cooling output over time.

Provided is an internal combustion engine control device capable of appropriately correcting a flow rate of EGR gas. Therefore, an internal combustion engine control device 20 includes moisture amount calculation units 301 and 302, a dew condensation calculation unit 303, and an EGR correction unit 304. The moisture amount calculation unit 301 calculates a total moisture amount contained in the mixed gas. The dew condensation calculation unit 303 calculates a dew condensation generation amount WQcon in an intercooler based on the total moisture amount. The EGR correction unit 304 corrects a flow rate of the EGR gas based on the dew condensation generation amount WQcon.