Method for inferring barometric pressure at low throttle angles
AssigneeFord Global Technologies, LLC
InventorsRommel Racelis, John Eric Rollinger, Robert Roy Jentz
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for estimating barometric pressure based on a reference barometric pressure and manifold pressures at two different altitudes. In one example, a method may include adjusting an operating condition of the engine based on barometric pressure during engine operation at throttle angles less than a threshold, the barometric pressure based on a current manifold pressure relative to a reference manifold pressure at a current throttle angle and reference barometric pressure. Further, the method may include adjusting a manifold pressure sensor output based on an offset of the manifold pressure sensor.
Claims20
An engine method, comprising:
- during throttle angles less than a threshold while an engine is carrying out combustion, adjusting one or more of cylinder air charge, air-fuel ratio, spark timing, and exhaust gas recirculation flow based on barometric pressure, the barometric pressure determined by setting the barometric pressure equal to a product of a reference barometric pressure and a ratio of a current manifold pressure to a reference manifold pressure at a current throttle angle.
An engine method, comprising:
- during a first condition, when a throttle angle of an intake throttle is less than a threshold and while an engine is carrying out combustion, adjusting an engine operating condition based on barometric pressure, the barometric pressure determined by setting the barometric pressure equal to a product of a reference barometric pressure and a ratio of a measured manifold pressure to a reference manifold pressure;
- and
- during a second condition, when the throttle angle is greater than the threshold, adjusting the engine operating condition based on barometric pressure, the barometric pressure determined based on the measured manifold pressure,
- wherein adjusting the engine operating condition based on barometric pressure includes one or more of adjusting an air-fuel ratio and adjusting spark timing.
A system, comprising:
- an intake manifold;
- a throttle positioned in the intake manifold;
- a manifold pressure sensor positioned in the intake manifold and configured to determine a measured manifold pressure;
- and
- a controller with computer readable instructions for adjusting engine operation responsive to barometric pressure, the barometric pressure determined based on the measured manifold pressure during engine operation at a throttle angle greater than a threshold, and the barometric pressure determined by setting the barometric pressure equal to a product of a reference barometric pressure and a ratio of the measured manifold pressure to a reference manifold pressure during engine operation at a throttle angle less than the threshold,
- wherein adjusting engine operation includes one or more of adjusting cylinder air charge, air-fuel ratio, spark timing, or exhaust gas recirculation flow.
An engine method, comprising:
- during throttle angles less than a threshold and while an engine is carrying out combustion, adjusting one or more of cylinder air charge, air-fuel ratio, spark timing, and exhaust gas recirculation flow based on barometric pressure, the barometric pressure based on a current manifold pressure, a reference manifold pressure at a current throttle angle, and a reference barometric pressure, wherein the current manifold pressure is based on a manifold pressure measured by a manifold pressure sensor and a sensor offset of the manifold pressure sensor, the manifold pressure sensor positioned in an intake manifold of the engine, the method further comprising estimating the sensor offset based on a first ratio between the measured manifold pressure and the reference manifold pressure and a second ratio between a current barometric pressure and the reference barometric pressure, the current barometric pressure based on an output of the manifold pressure sensor during wide open throttle or engine start-up.
Dependencies are inferred from the claim text.