Methods and systems are provided for estimating an engine exhaust pressure based on outputs from an exhaust oxygen sensor. In one example, a method may include estimating an exhaust pressure of exhaust gas flowing through an engine exhaust passage based on a difference between a first output of an oxygen sensor disposed in the exhaust passage and a second output of the oxygen sensor and then adjusting engine operation based on the estimated exhaust pressure. As one example, both the first and second outputs may be taken while operating the sensor in a variable voltage mode, after increasing a reference voltage of the oxygen sensor from a lower, first voltage to a higher, second voltage.

Methods and systems are provided for mitigating excessive exhaust pressures in an engine. In one example, a method may include adjusting an intake throttle responsive to exhaust pressure upstream of an exhaust turbine being higher than a threshold without reducing boost level. In this way, boost pressures may be maintained while reducing exhaust pressures.

Controlling turbocharger boost pressure using exhaust pressure estimated from engine cylinder pressure.

A driving device for driving a vehicle includes an internal combustion engine, a feed line for feeding combustion air to the internal combustion engine, a discharge line for discharging exhaust gases from the internal combustion engine, a charge air cooler that is arranged in the feed line for cooling the combustion air, and a recirculation line branching off the discharge line for recirculating the exhaust gas from the discharge line into the feed line. The recirculation line includes a bypass line that the exhaust gas can be fed to the internal combustion engine through the charge air cooler and/or bypassing the charge air cooler.

In a turbocharged internal combustion engine, an amount of cylinder suction air is calculated with sufficiently high accuracy to suitably control the internal combustion engine in consideration of influences of an exhaust pressure on a volumetric efficiency equivalent value without requiring a huge memory capacity, in fewer adaptive man hours, and under a low operation load. A correction calculation parameter is calculated using an exhaust pressure, an exhaust pressure for pre-correction volumetric efficiency equivalent value, and an intake manifold pressure, and a post-corrected volumetric efficiency equivalent value is calculated by correcting a pre-correction volumetric efficiency equivalent value using the correction calculation parameter. An amount of air entering a cylinder from an intake manifold is calculated on the basis of the post-correction volumetric efficiency equivalent value.

Disclosed is a turbocharger control device of a vehicle and a method of estimating base boost pressure using the same. The turbocharger control device of a vehicle includes a status information collection unit for collecting real-time status information according to an operation of a turbocharger when a vehicle is operated from various types of sensors, and a control unit for precisely estimating a base boost pressure by excluding a turbocharger boost pressure from a current boost pressure through a turbine power function and a compressor power function based on a physical model based on the collected status information.

A pressure monitor is arranged to calculate a pre-turbine pressure. The monitor is programmed to derive a normalized turbine speed, normalized for a pre turbine temperature, and a heat capacity ratio of exhaust gas before the turbine as first inputs; determine a turbine power normalizing factor as a second input; determine an actual turbocompressor power value as a third input; derive, for said first inputs, a linear relation between a turbine expansion ratio and a turbine power value normalized by the second input; and equate the turbine power value to the actual turbocompressor power; thereby deriving the pre turbine pressure from said linear relation, as an output.

Disclosed is a turbocharger control device of a vehicle and a method of estimating base boost pressure using the same. The turbocharger control device of a vehicle includes a status information collection unit for collecting real-time status information according to an operation of a turbocharger when a vehicle is operated from various types of sensors, and a control unit for precisely estimating a base boost pressure by excluding a turbocharger boost pressure from a current boost pressure through a turbine power function and a compressor power function based on a physical model based on the collected status information.

An engine assembly comprises an exhaust gas recirculation circuit, an aftertreatment apparatus and a controller. The controller is configured to determine a desired proportion of exhaust gas to be directed to the exhaust gas recirculation circuit. The controller is further configured to determine, based on the proportion of exhaust gas to be directed to the exhaust gas recirculation circuit, a baseline value for an extent to which to open the exhaust gas recirculation valve for a clean aftertreatment apparatus. The controller is further configured to determine a compensation function based on an inferred aftertreatment flow restriction value. The controller is further configured to control the extent to which the exhaust gas recirculation valve is open based on the baseline value modified by the compensation function in order to maintain the desired proportion of exhaust gas to be directed to the exhaust gas recirculation circuit.