Method and device for estimating the intake air flow rate in an internal combustion engine

Abstract

A method is described for estimating the intake air flow rate in an internal combustion engine (1) provided with an air intake system (2), wherein said system comprises valve means (6) for controllingan intake air flow rate, characterized in that it comprises the phases of implementing a first and a second algorithm, suitable to determine respectively a first ( MAF_SV ) and a second ( MAF_FE ) en gine intake air flow rate; and of selecting the first ( MAF_SV ) or the second ( MAF_FE ) flow rate, on the basis of a previously defined selection criterion.

Description

technical field [0001] The invention relates to a method and a device for estimating the air intake flow rate of an internal combustion engine. Background technique [0002] As stated in the prior art, in order to meet the mandatory pollutant emission requirements of new generation vehicles, especially those equipped with modern indirect gasoline injection engines using three-way catalysts, the air-fuel ratio must be precisely controlled so that it is always close to the chemical Measured value, the purpose is to reduce exhaust emissions. [0003] For this reason, modern automobiles are usually equipped with an air flow meter (debimeter), which is generally located in the intake system of the engine, and is used to give an electrical signal to indicate the flow of fresh air supplied to the engine. Previously, and based on this signal, the electronic control unit calculated the fuel flow to be injected into the engine cylinders based on the required air-fuel ratio. [0004]...

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Problems solved by technology

[0008] In addition, studies conducted by the applicant have shown that even when known algorithms are used, the mass of air entering a variable timing engine cannot be accurately estimated

In fact, this algorithm does not take into account the effect of the engine positive displacement pump when the engine speed changes, the engine speed change will have a significant impact on the intake air flow, especially in the high pressure area, for example, the pressure ratio at the throttle is between 0.9-0.95 , or any mechanical timing error, or any sudden change in intake timing, etc. Also, in the case of drive-by-wire systems, these algorithms do not correctly reproduce the transition between torque law and mechanical law

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