MAP sensor

Abstract: An electronic engine controller for a diesel engine controls the mass of fuel injected by fuel injectors within the engine by receiving a Manifold Absolute Pressure (MAP) signal, from a MAP sensor positioned in an intake manifold of the engine, and generating a value indicative of the mass of fuel to be injected by the fuel injectors as a function of the MAP signal. The engine controller also generates an estimate of the absolute air pressure existing in the intake manifold by retrieving a value from a table containing a plurality of values indicative of an absolute air pressure for a given engine speed and fuel injection quantity. If the MAP sensor fails then the engine controller utilizes the estimate to generate the value indicative of the mass of fuel to be injected by the fuel injectors.

Abstract: A pressure and temperature sensor assembly for internal combustion engines is disclosed. The sensor assembly is formed by integrating a temperature sensor part with a conventional MAP sensor into a single structure. In the temperature sensor part, a temperature sensing rod (23) is formed by partially extending downward the bottom case (7) of a MAP sensor at a portion around the lower end of a pressure inlet port (9) of the bottom case (7). A temperature sensor chip (24) is interiorly installed in the temperature sensing rod (23) and is electrically connected to the connection terminals of the top case (1). The sensor assembly is commonly used for sensing both the internal pressure and inlet air temperature of a cylinder.

Abstract: Flexible fuel vehicles (FFVs) can operate on a blend of ethanol and gasoline in any volumetric concentration of up to 85% ethanol (93% in Brazil). Existing FFVs rely on ethanol sensor installed in the vehicle fueling system, or on an ethanol estimation based on air-to-fuel ratio (AFR) regulation via an exhaust gas oxygen (EGO) or λ sensor. The EGO-based ethanol detection is desirable from cost and maintenance perspectives but it is known to be prone to large errors during mass air flow sensor drifts. Ethanol content estimation can be realized by a feedback-based fuel correction of the feedforward-based fuel calculation using an exhaust gas oxygen sensor. When the fuel correction is attributed to the difference in stoichiometric air-to-fuel ratio (SAFR) between ethanol and gasoline, it can be used for ethanol estimation. When the fuel correction is attributed to a mass air flow (MAF) sensor error, it can be used for sensor drift estimation and correction. Deciding under which condition to blame (and detect) ethanol and when to switch to sensor correction burdens the calibration of FFV engine controllers. Moreover, erroneous decisions can lead to biases in ethanol estimation and in MAF sensor correction. In this paper, we present AFR-based ethanol content estimation, associated sensitivity and dynamical analysis, and a cylinder air flow estimation scheme that accounts for MAF sensor drift or bias using an intake manifold absolute pressure (MAP) sensor. The proposed fusion of the MAF, MAP, and λ sensor measurements prevents severe misestimation of ethanol content in flex fuel vehicles.

Abstract: A MAP (Manifold Air Pressure) sensor diagnostic method for a vehicle is provided which uses a calculated intake manifold air pressure as the intake manifold air pressure if the output signal of the MAP sensor is not within a predetermined range, or if the difference between the intake manifold air pressure indicated by the MAP sensor signal and the calculated intake manifold air pressure is not less than a predetermined value.