A method for the fuel consumption reduction and/or power increase of an internal combustion engine of a motor vehicle is disclosed. A crank angle of a crankshaft is detected at which out of a cylinder the exhaust gases of a cylinder can be representatively measured on a lambda probe. The exhaust gas flow is measured on the lambda probe. A signal of the lambda probe is scanned at the time of the detection of the crank angle. A value indicated the detected angle and/or the scanned signal is sent to a computer. The value is corrected with the help of an exhaust gas pressure or exhaust gas back pressure model stored in the computer. An effective combustion lambda of the cylinder is calculated based on the sent values and a global lambda value stored in the computer and used to the control of the internal combustion engine.

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 for provided for accurately estimating an engine intake or exhaust manifold pressure using a laser pressure transducer. Laser circuitry is coupled to a pressure sensitive diaphragm that is mounted to the engine manifold. Manifold pressure is inferred based on a deflection of the diaphragm, as estimated based on a timing between emission of a laser pulse into the diaphragm and detection of a reflected pulse from the diaphragm.

A control system for an engine of a vehicle includes an adder module that determines a temperature sum based on a sum of a plurality of temperatures determined based on (i) a plurality of operating parameters of the vehicle and (ii) a plurality of predetermined values calibrated for determining an estimated temperature at a location within an exhaust system of the vehicle. A temperature difference module determines a temperature difference based on the temperature sum and a previous value of the temperature difference. An estimating module determines the estimated temperature at the location within the exhaust system based on the temperature difference and a reference temperature. An actuator control module selectively adjusts at least one engine actuator based on the estimated temperature.

Methods and systems are provided for detecting air-fuel ratio imbalances across all engine cylinders. In one example, a method (or system) may include indicating cylinder imbalance based on each of the exhaust air-fuel ratio, exhaust manifold pressure, and cylinder torque weighted by a confidence factor, where in the confidence factor is determined based on operating conditions.

A control system for an engine of a vehicle includes an adder module that determines a pressure sum based on a sum of a plurality of pressures determined based on (i) a plurality of operating parameters of the vehicle and (ii) a plurality of predetermined values calibrated for determining an estimated pressure at a location within an exhaust system of the vehicle. An estimating module determines the estimated pressure at the location within the exhaust system based on the pressure sum and a reference pressure. An actuator control module selectively adjusts at least one engine actuator based on the estimated pressure.

A basic EGR flow rate calculation part calculates a basic EGR flow rate based on an intake manifold pressure, which is a pressure in an intake manifold, an exhaust pressure, which is a pressure in an exhaust pipe, an exhaust temperature, which is a temperature in the exhaust pipe, and an opening degree of an EGR valve. An EGR flow rate correction part corrects the basic EGR flow rate based on an intake manifold pressure ratio, which is a ratio between the intake manifold pressure and the exhaust pressure, and an exhaust VVT phase angle of an exhaust VVT mechanism, to thereby calculate a corrected EGR flow rate as an EGR flow rate.

A control system for an engine of a vehicle includes an adder module that determines a temperature sum based on a sum of a plurality of temperatures determined based on (i) a plurality of operating parameters of the vehicle and (ii) a plurality of predetermined values calibrated for determining an estimated temperature at a location within an exhaust system of the vehicle. A temperature difference module determines a temperature difference based on the temperature sum and a previous value of the temperature difference. An estimating module determines the estimated temperature at the location within the exhaust system based on the temperature difference and a reference temperature. An actuator control module selectively adjusts at least one engine actuator based on the estimated temperature.

A control system for an engine of a vehicle includes an adder module that determines a pressure sum based on a sum of a plurality of pressures determined based on (i) a plurality of operating parameters of the vehicle and (ii) a plurality of predetermined values calibrated for determining an estimated pressure at a location within an exhaust system of the vehicle. An estimating module determines the estimated pressure at the location within the exhaust system based on the pressure sum and a reference pressure. An actuator control module selectively adjusts at least one engine actuator based on the estimated pressure.

A method for controlling a two-stroke engine operatively connected to a turbocharger, the turbocharger being in fluid communication with the engine to provide a boost pressure thereto. The method includes determining an exhaust temperature representative of an actual temperature of exhaust gas being discharged by the engine; determining a temperature difference between the exhaust temperature and a threshold temperature; in response to the exhaust temperature being less than the corresponding threshold value: determining a corrective amount of boost pressure to add to the boost pressure of the turbocharger, the corrective amount of boost pressure being determined based on the temperature difference; and controlling the turbocharger to increase the boost pressure of the turbocharger by the corrective amount.