A method for calculating the mass of an overlap gaseous flow (M.sub.OVL), wherein the exhaust pressure is higher than the intake pressure, or in the case of scavenging (SCAV), wherein the intake pressure is higher than the exhaust pressure. The overlap gaseous flow (M.sub.OVL) is the flow which flows, in overlap conditions, through the intake valve and the exhaust valve of a cylinder of an internal combustion engine. At least one intake valve is driven so as to vary the lift (H) of the intake valve in controlled manner. The overlap condition is a condition in which the intake valve and the exhaust valve are both at least partially open. The method comprises calculating the mass of the gaseous flow (M.sub.OVL) which flows through the intake valve and the exhaust valve on the basis of the relation:

M.sub.OVL=PERM*β(P/P.sub.0,n)*P.sub.0/P.sub.0_REF*(T.sub.0_REF/T.sub.0).sup.1/2/n.

According to the invention, a method for air path control of a combustion engine is provided, comprising an EGR valve and a VGT turbine. The method comprises providing a cost function of a measured delta pressure between engine intake and exhaust manifold; determining a gradient of the cost function as a function of a delta pressure set point, determining a gradient of a constraint function for estimated NOx emission level, turbine rate; and oxygen level as a function of delta pressure; real time controlling the NOx emission level and delta pressure to respective desired NOx and delta pressure set points by adjusting the EGR valve and/or the VGT turbine, wherein the delta pressure set point is adjusted according to an integration of a selected gradient direction of the cost function selected from the determined one or more of the gradients, wherein the determined gradients are prioritized in the order of turbine rate, oxygen level and NOx emission level; and wherein NOx emission level and or a turbine rate and or oxygen levels are constrained; and wherein the adjusted delta pressure set point is perturbed in an extremum seeking operation on the cost function.

A method for calculating the mass of an overlap gaseous flow (M.sub.OVL), wherein the exhaust pressure is higher than the intake pressure, or in the case of scavenging (SCAV), wherein the intake pressure is higher than the exhaust pressure. The overlap gaseous flow (M.sub.OVL) is the flow which flows, in overlap conditions, through the intake valve and the exhaust valve of a cylinder of an internal combustion engine. At least one intake valve is driven so as to vary the lift (H) of the intake valve in controlled manner. The overlap condition is a condition in which the intake valve and the exhaust valve are both at least partially open. The method comprises calculating the mass of the gaseous flow (M.sub.OVL) which flows through the intake valve and the exhaust valve on the basis of the relation:
M.sub.OVL=PERM*β(P/P.sub.0,n)*P.sub.0/P.sub.0_REF*(T.sub.0_REF/T.sub.0).sup.1/2/n.

A controller, in shifting the state of the EGR system from the EGR operating state to the EGR non-operating state at the time of performing the deceleration of the vehicle, calculates a provisional EGR ratio that is a provisional value of the current EGR ratio, estimates the provisional EGR ratio as the actual EGR ratio when a fore-and-aft differential pressure of the EGR valve is equal to or more than a predetermined value, performs correction to make the provisional EGR ratio smaller, and estimates the corrected provisional EGR ratio as the actual EGR ratio when the fore-and-aft differential pressure of the EGR valve is less than the predetermined value.

A vehicle controller includes processing circuitry and a storage device. The storage device stores relationship specifying data that specifies a relationship between a state of a vehicle and at least one action variable. The at least one action variable is a variable related to operation of an operating unit of an internal combustion engine. The processing circuitry is configured to execute an obtaining process that obtains a state of the vehicle, an operating process that operates the operating unit based on a value of the at least one action variable, a reward calculation process, an updating process that updates the relationship specifying data, and a determination process that determines whether the internal combustion engine has deteriorated. The determination process is executed on condition that at least one of the at least one action variable equals a predetermined value.

A negative pressure control valve (44) is disposed in a part of an intake passage (12) upstream of a confluence (30) of an EGR passage (27) and the intake passage (12). When in an EGR region (Regr) where an EGR gas is recirculated to the intake passage (12) through the EGR passage (27), the negative pressure control valve (44) is controlled in a manner to ensure a differential pressure between an exhaust passage (13) and the intake passage (12). When in an operation region (R2) lower in load than the EGR region (Regr), the negative pressure control valve (44) is controlled in a closing direction so as to suppress occurrence of noise.

An automobile power system in a vehicle may include an intake pipe supplying external air to an engine supplying power to driving wheels, a canister connected with a fuel tank to absorb evaporation gas produced in the fuel tank, an active purging system compressing and supplying the evaporation gas absorbed in the canister to the intake pipe, a diverging line extending from the active purging system to the engine, a diverging valve mounted on the diverging line, and a starting motor rotating a crankshaft when the engine is started. In addition, the evaporation gas absorbed in the canister is supplied to the engine through the diverging line before the engine is restarted, and then the starting motor is operated.

Methods and systems for operating an engine that includes adjustable poppet valve timing and an exhaust gas recirculation valve are described. In one example, the exhaust gas recirculation valve is opened and the timing of the poppet valves is retarded so that an amount of fresh air that is pumped by the engine to an after treatment device may be reduced.

This engine system is provided with a throttle device, an EGR valve, and an ECU. The ECU diagnoses an abnormality of the EGR valve on the basis of an operating state during an engine deceleration, and diagnoses combustion deterioration of an engine on the basis of a crank angle speed change during the engine deceleration (not during a fuel cut-off). The ECU executes an engine stall avoidance control with the throttle device when it is determined there is an abnormality in the EGR valve, makes a final determination that the EGR valve has an abnormality and continues the engine stall avoidance control when it is determined thereafter that there is combustion deterioration, and makes a final determination that the EGR valve is normal and cancels the engine stall avoidance control when it is determined that there is no combustion deterioration.

According to the invention, a method for air path control of a combustion engine is provided, comprising an EGR valve and a VGT turbine. The method comprises providing a cost function of a measured delta pressure between engine intake and exhaust manifold; determining a gradient of the cost function as a function of a delta pressure set point, determining a gradient of a constraint function for estimated NOx emission level, turbine rate; and oxygen level as a function of delta pressure; real time controlling the NOx emission level and delta pressure to respective desired NOx and delta pressure set points by adjusting the EGR valve and/or the VGT turbine, wherein the delta pressure set point is adjusted according to an integration of a selected gradient direction of the cost function selected from the determined one or more of the gradients, wherein the determined gradients are prioritized in the order of turbine rate, oxygen level and NOx emission level; and wherein NOx emission level and or a turbine rate and or oxygen levels are constrained; and wherein the adjusted delta pressure set point is perturbed in an extremum seeking operation on the cost function.