Single-cylinder air-fuel ratio closed-loop control method based on oxygen sensor for multi-cylinder engine

Abstract

The invention discloses a single-cylinder air-fuel ratio closed-loop control method based on an oxygen sensor for a multi-cylinder engine. It is determined to enter the single-cylinder air-fuel ratio closed-loop control: judge the first operating state of each cylinder, and in the same first operating state of each cylinder, the oxygen sensor performs sampling respectively, and converts the sampling data group into the real-time air-fuel ratio of each cylinder; Determine the second operating state of each cylinder, compare the real-time air-fuel ratio of each cylinder with the target air-fuel ratio, calculate and determine the closed-loop correction coefficient of each cylinder, correct the basic fuel injection quantity of each cylinder, and determine the fuel injection quantity of each cylinder. The invention adopts the oxygen sensor to sample at a specific sampling time, fully considers the influence of the transient working condition of the engine on the air-fuel ratio of each cylinder of the engine, realizes precise control, and takes into account the steady-state influence at the same time, avoiding the transitional adjustment and correction of the transient working condition. The invention realizes the single-cylinder air-fuel ratio closed-loop control, improves the unevenness of the air-fuel ratio control of each cylinder, reduces emission, improves power torque, and reduces fuel consumption.

Description

technical field [0001] The invention belongs to engine electronic control technology, and in particular relates to a control technology of fuel injection amount of a multi-cylinder engine, in particular to a single-cylinder air-fuel ratio closed-loop control technology under the engine multi-cylinder air-fuel ratio closed-loop control system. Background technique [0002] The air-fuel ratio is an important parameter for engine control, and the difference in charging efficiency caused by the design of the engine intake manifold or the unevenness of EGR intake, and the difference in the hardware of the injector will cause the difference in the air-fuel ratio of each cylinder. The difference in the air-fuel ratio of each cylinder will increase emissions and fuel consumption. [0003] The existing control method is to compensate the difference of air-fuel ratio of each cylinder through open-loop control, but this method cannot solve the problem of the difference of air-fuel rati...

AI Technical Summary

Problems solved by technology

Its essence is to solve the problem of reducing the vibration of the engine, not suitable for directly solving the problem of engine emission

In addition, because the fuel injection correction coefficients of each cylinder of the engine are obtained by looking up the table, the workload of the test and test in the early stage of development is heavy.

Images