Method for adjusting the fuel mixture in an internal combustion engine

Abstract

The invention relates to a method for adjusting the richness of a mixture of fresh air and fuel injected into a combustion chamber of a spark-ignition internal combustion engine which includes an exhaust line equipped with a first catalyst, a second catalyst located downstream of the first, as well as an upstream richness sensor located upstream of the first catalyst, an intermediate richness sensor located between the first and second catalysts, and a downstream richness sensor located downstream of the second catalyst, the adjustment method comprising: - a step of acquiring the richness of the exhaust gases measured by the upstream sensor, - a step of calculating a richness setpoint (Cλ), and - a step of determining a control parameter (Ti) of the internal combustion engine to regulate the richness of the exhaust gases acquired according to said richness setpoint.According to the invention, the fuel mixture setpoint is modified according to the values ​​of the exhaust gas flow rate, the fuel-air mixture measured by the intermediate probe, and the fuel-air mixture measured by the downstream probe. Figure for the abstract: Fig. 3.

Claims

corrected when regulation resumed.

9. Adjustment method according to one of claims 1 to 8, wherein said control parameter (TO) is a duration of fuel injection into the combustion chamber at each operating cycle of the internal combustion engine (1).

10. Internal combustion engine (1) of the spark-ignition type comprising: - a combustion chamber, - an exhaust line (80) for gases burned outside the combustion chamber which is equipped with a first catalyst (84), a second catalyst (86) located downstream of the first catalyst (84), as well as an upstream richness sensor (40) located upstream of the first catalyst (84), an intermediate richness sensor (41) located between the first and second catalysts (84, 86), and a downstream richness sensor (42) located downstream of the second catalyst (84, 86), and - a computer programmed to implement an adjustment method according to one of claims 1 to 9. [Fig. 1] [Fig. 2]

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