Methods and systems are provided for determining an offset of a manifold pressure sensor. In one example, an engine method may include indicating degradation of the manifold pressure sensor based on a sensor offset, the sensor offset based on a manifold pressure measured at a first throttle angle, a barometric pressure at a second throttle angle, a reference manifold pressure at the first throttle angle and reference barometric pressure, and the reference barometric pressure. Further, the method may include adjusting an output of the manifold pressure sensor by the determined sensor offset.

A method for controlling an internal combustion engine with a crankshaft position sensor, intake air pressure sensor and fresh air intake throttle valve, includes: determining the engine's rotational speed based on the crankshaft position derivative relative to time; determining the intake air pressure for a first crankshaft position corresponding to 180° before top dead center; determining the intake air pressure for a second crankshaft position corresponding to 390° before top dead center; determining an atmospheric pressure learning pressure threshold based on the engine's rotational speed; determining whether the difference between the intake air pressures for the first and second crankshaft positions is below the atmospheric pressure learning pressure threshold; if so, commanding atmospheric pressure learning by applying a first-order filter to the intake air pressure for the second crankshaft position; and controlling the internal combustion engine as a function of the learned atmospheric pressure value.

A method for controlling an internal combustion engine with a crankshaft position sensor, intake air pressure sensor and fresh air intake throttle valve, includes: determining the engine's rotational speed based on the crankshaft position derivative relative to time; determining the intake air pressure for a first crankshaft position corresponding to 180° before top dead center; determining the intake air pressure for a second crankshaft position corresponding to 390° before top dead center; determining an atmospheric pressure learning pressure threshold based on the engine's rotational speed; determining whether the difference between the intake air pressures for the first and second crankshaft positions is below the atmospheric pressure learning pressure threshold; if so, commanding atmospheric pressure learning by applying a first-order filter to the intake air pressure for the second crankshaft position; and controlling the internal combustion engine as a function of the learned atmospheric pressure value.

Methods and systems are provided for cleaning a fuel vapor storage canister positioned in an evaporative emissions control system of a vehicle. In one example, a method comprises sealing a fuel system of the vehicle for descending an altitude change that is predicted in advance, and subsequent to the vehicle descending the altitude change, unsealing the fuel system to passively purge fuel vapors stored in the fuel vapor storage canister to a fuel tank of the vehicle. In this way, bleed through emissions from the fuel vapor storage canister may be reduced, and engine operation may be improved.

Methods and systems are provided for determining barometric pressure. In one example, an onboard vacuum pump is utilized to draw a vacuum at a constant flow rate across a reference orifice, and the resulting vacuum level is converted to a barometric pressure. In this way, other sensors for determining barometric pressure in a vehicle may be rationalized without the use of engine operation, and in an example where the other sensors for determining barometric pressure are not functioning as desired, barometric pressure as inferred from the onboard pump may be utilized to adjust engine operation.

Methods and systems are provided for cleaning a fuel vapor storage canister positioned in an evaporative emissions control system of a vehicle. In one example, a method comprises sealing a fuel system of the vehicle for descending an altitude change that is predicted in advance, and subsequent to the vehicle descending the altitude change, unsealing the fuel system to passively purge fuel vapors stored in the fuel vapor storage canister to a fuel tank of the vehicle. In this way, bleed through emissions from the fuel vapor storage canister may be reduced, and engine operation may be improved.

A method for determining atmospheric pressure AMP during operation in a partial load state of a turbocharged engine (1) including an air intake line (2) incorporating a butterfly valve (16), and an exhaust line (3) including a bypass duct (20) incorporating an exhaust gas discharge valve (21), the method includes measuring the air pressure PUT upstream of the butterfly valve (16), and for a given speed of N rpm of the engine (1), when the boost pressure PUT corresponds substantially to the natural boost pressure, determining the atmospheric pressure AMP=AMP(0)+PUTPUT(0), wherein AMP(0) is the atmospheric pressure previously measured, and PUT(0) is boost pressure naturally obtained for the speed N rpm of the engine (1) for the atmospheric pressure AMP(0).

A method to determine a status of a motor vehicle includes collecting a first output signal data from at least one device which is outputting the signal data related to a first plurality of operational parameters and a first plurality of environmental parameters of the motor vehicle. The method further includes identifying patterns within the first output signal data, analyzing the patterns within the first output signal data; and generating a second output signal data defining a second plurality of operational parameters distinct from the first operational parameters.

Methods and systems are provided for determining barometric pressure. In one example, an onboard vacuum pump is utilized to draw a vacuum at a constant flow rate across a reference orifice, and the resulting vacuum level is converted to a barometric pressure. In this way, other sensors for determining barometric pressure in a vehicle may be rationalized without the use of engine operation, and in an example where the other sensors for determining barometric pressure are not functioning as desired, barometric pressure as inferred from the onboard pump may be utilized to adjust engine operation.

A method for determining a quantity of air within a cylinder of an internal combustion engine includes the steps of scaling an intake manifold pressure and an exhaust gas pressure in dependence on an actual ambient air pressure and a standard ambient air pressure in order to provide a scaled intake manifold pressure and a scaled exhaust gas pressure, implementing an air charge calculating algorithm produced under a standard ambient air pressure operating condition, in order to determine a standard quantity of air based on the scaled intake manifold pressure and the scaled exhaust gas pressure, and scaling the standard quantity of air in dependence on the actual ambient air pressure and the standard ambient air pressure in order to calculate the quantity of air within the cylinder of the internal combustion engine. An engine control unit and a method for controlling an internal combustion engine are also provided.