Method and apparatus for detecting pneumatic pressure in an internal combustion engine

Claim 1

A method of detecting pneumatic pressure in an internal combustion engine having a single absolute pressure sensor for detecting the absolute pneumatic pressure of a fluid applied to the sensor, an intake passage, a throttle valve disposed on the intake passage, and a pressure detection port open to the intake passage at a position located downstream of the throttle valve, said method comprising the steps of: detecting the absolute pneumatic pressure in the intake passage downstream of the throttle valve and the atmospheric pressure by selectively communicating said absolute pressure sensor to said pressure detection port of the intake passage or to the open air, said detection of the atmospheric pressure being executed only initially and when the engine is operated under a pedetermined operating condition, where the difference between the detected absolute pneumatic pressure and the detected atmospheric pressure is less than a predetermined value, after a predetermined period of time has elapsed since the previous detection of the atmospheric pressure and calculating the relative pneumatic pressure in the intake passage downstream of the throttle valve from said detected absolute pneumatic pressure in the intake passage and from said atmospheric pressure.

Claim 2

A method of detecting pneumatic pressure in an internal combustion engine having a single absolute pressure sensor for detecting the absolute pneumatic pressure of a fluid applied to the sensor, an intake passage, a throttle valve disposed on the intake passage, and a pressure detection port open to the intake passage at a position located downstream of the throttle valve, said method comprising the steps of: detecting the absolute pneumatic pressure in the intake passage downstream of the throttle valve and the atmospheric pressure by selectively communicating said absolute pressure sensor to said pressure detection port of the intake passage or to the open air, said detection of the atmospheric pressure being executed only initially and when the engine is operated under a pedetermined operating condition, where the difference between the detected absolute pneumatic pressure and the detected atmospheric pressure is less than a predetermined value, after a predetermined period of time has elapsed since the previous detection of the atmospheric pressure and calculating the relative pneumatic pressure in the intake passage downstream of the throttle valve from said detected absolute pneumatic pressure in the intake passage and from said atmospheric pressure.

Claim 4

A method of detecting pneumatic pressure in an internal combustion engine having a single absolute pressure sensor for detecting the absolute pneumatic pressure of a fluid applied to the sensor, an intake passage, a throttle valve disposed on the intake passage, and a pressure detection port open to the intake passage at a position located downstream of the throttle valve, said method comprising the steps of: detecting the absolute pneumatic pressure in the intake passage downstream of the throttle valve and the atmospheric pressure by selectively communicating said absolute pressure sensor to said pressure detection port of the intake passage or to the open air; storing said detected absolute pneumatic pressure in the intake passage and said detected atmospheric pressure; discriminating, in response to the stored absolute pneumatic pressure and the stored atmospheric pressure, whether or not the engine is operated under a predetermined operating condition where the difference between the stored absolute pneumatic pressure and the stored atmospheric pressure is less than a predetermined value, in order to communicate said absolute pressure sensor to the open air so as to execute said detection of the atmospheric pressure only initially and when the engine is operated under said predetermined operating condition after a predetermined period of time has elapsed since the previous detection of the atmospheric pressure; and calculating the relative pneumatic pressure in the intake passage downstream of the throttle valve from said detected absolute pneumatic pressure in the intake passage and from said atmospheric pressure.

Claim 5

A method of detecting pneumatic pressure in an internal combustion engine having a single absolute pressure sensor for detecting the absolute pneumatic pressure of a fluid applied to the sensor, an intake passage, a throttle valve disposed on the intake passage, and a pressure detection port open to the intake passage at a position located downstream of the throttle valve, said method comprising the steps of: detecting the absolute pneumatic pressure in the intake passage downstream of the throttle valve and the atmospheric pressure by selectively communicating said absolute pressure sensor to said pressure detection port of the intake passage or to the open air; storing said detected absolute pneumatic pressure in the intake passage and said detected atmospheric pressure; discriminating, in response to the stored absolute pneumatic pressure and the stored atmospheric pressure, whether or not the engine is operated under a predetermined operating condition where the difference between the stored absolute pneumatic pressure and the stored atmospheric pressure is less than a predetermined value, in order to communicate said absolute pressure sensor to the open air so as to execute said detection of the atmospheric pressure only initially and when the engine is operated under said predetermined operating condition after a predetermined period of time has elapsed since the previous detection of the atmospheric pressure; and calculating the relative pneumatic pressure in the intake passage downstream of the throttle valve from said detected absolute pneumatic pressure in the intake passage and from said atmospheric pressure.

Claim 7

An apparatus for detecting pneumatic pressure in an internal combustion engine having an intake passage, a throttle valve disposed on the intake passage, and a pressure detection port open to the intake passage at a position located downstream of the throttle valve, said apparatus comprising: a single absolute pressure sensor for detecting the absolute pneumatic pressure of a fluid applied thereto; means for selectively communicating said absolute pressure sensor to said pressure detection port of the intake passage or to the open air so as to detect the absolute pneumatic pressure in the intake passage downstream of the throttle valve and the atmospheric pressure, said absolute pressure sensor being communicated with the open air only initially and when the engine is operated under a predetermined operating condition, where the difference between the detected absolute pneumatic pressure and the detected atmospheric pressure is less than a predetermined value, after a predetermined period of time has elapsed since the previous detection of the atmospheric pressure; and means for calculating the relative pneumatic pressure in the intake passage downstream of the throttle valve from said detected absolute pneumatic pressure in the intake passage and from said atmospheric pressure.

Claim 8

An apparatus for detecting pneumatic pressure in an internal combustion engine having an intake passage, a throttle valve disposed on the intake passage, and a pressure detection port open to the intake passage at a position located downstream of the throttle valve, said apparatus comprising: a single absolute pressure sensor for detecting the absolute pneumatic pressure of a fluid applied thereto; means for selectively communicating said absolute pressure sensor to said pressure detection port of the intake passage or to the open air so as to detect the absolute pneumatic pressure in the intake passage downstream of the throttle valve and the atmospheric pressure, said absolute pressure sensor being communicated with the open air only initially and when the engine is operated under a predetermined operating condition, where the difference between the detected absolute pneumatic pressure and the detected atmospheric pressure is less than a predetermined value, after a predetermined period of time has elapsed since the previous detection of the atmospheric pressure; and means for calculating the relative pneumatic pressure in the intake passage downstream of the throttle valve from said detected absolute pneumatic pressure in the intake passage and from said atmospheric pressure.

Claim 10

An apparatus for detecting pneumatic pressure in an internal combustion engine having an intake passage, a throttle valve disposed on the intake passage, and a pressure detection port open to the intake passage at a position located downstream of the throttle valve, said apparatus comprising: a single absolute pressure sensor for detecting the absolute pneumatic pressure of a fluid applied thereto; means for selectively communicating said absolute pressure sensor to said pressure detection port of the intake passage or to the open air so as to detect the absolute pneumatic pressure in the intake passage downstream of the throttle valve and the atmospheric pressure; means for storing the detected absolute pneumatic pressure and the detected atmospheric pressure; means for discriminating, in response to the stored absolute pneumatic pressure and stored atmospheric pressure, whether or not the engine is operated under a predetermined operating condition where the difference between the stored absolute pneumatic pressure and the stored atmospheric pressure is less than a predetermined value, in order to control said communicating means so that said absolute pressure sensor is communicated with the open air only initially and when the engine is operated under said predetermined operating condition after a predetermined period of time has elapsed since the previous communication with the open air; and means for calculating the relative pneumatic pressure in the intake passage downstream of the throttle valve from said detected absolute pneumatic pressure in the intake passage and from said atmospheric pressure.

Claim 11

An apparatus for detecting pneumatic pressure in an internal combustion engine having an intake passage, a throttle valve disposed on the intake passage, and a pressure detection port open to the intake passage at a position located downstream of the throttle valve, said apparatus comprising: a single absolute pressure sensor for detecting the absolute pneumatic pressure of a fluid applied thereto; means for selectively communicating said absolute pressure sensor to said pressure detection port of the intake passage or to the open air so as to detect the absolute pneumatic pressure in the intake passage downstream of the throttle valve and the atmospheric pressure; means for storing the detected absolute pneumatic pressure and the detected atmospheric pressure; means for discriminating, in response to the stored absolute pneumatic pressure and stored atmospheric pressure, whether or not the engine is operated under a predetermined operating condition where the difference between the stored absolute pneumatic pressure and the stored atmospheric pressure is less than a predetermined value, in order to control said communicating means so that said absolute pressure sensor is communicated with the open air only initially and when the engine is operated under said predetermined operating condition after a predetermined period of time has elapsed since the previous communication with the open air; and means for calculating the relative pneumatic pressure in the intake passage downstream of the throttle valve from said detected absolute pneumatic pressure in the intake passage and from said atmospheric pressure.