Split cylinder independent closed loop control method for homogeneous charge compression ignition (HCCI) combustion on basis of knock sensor

Abstract

The invention discloses a split cylinder independent closed loop control method for homogeneous charge compression ignition (HCCI) combustion on the basis of a knock sensor, which belongs to the technical field of internal combustion engines and comprises the following steps of utilizing the knock sensor to detect a vibration signal during combustion of the engine; utilizing an electronic control unit (ECU) to perform integral evaluation to obtain a knock strength value according to a vibration signal of the knock sensor; and setting a target value, an upper limit value and a lower limit value of knock input (KI)_i in an ECU procedure. When the knock strength of some cylinder is higher than KI_max, the oil jetting ratio for secondary jetting in the cylinder is increased to enable combustion phase to be delayed; and when the knock strength value of the cylinder is lower than KI_min, the oil jetting ratio for the secondary jetting in the cylinder is decreased to enable the combustion phase to be advanced. Therefore, based on the signal of the knock sensor, the KI_i value is controlled in a closed loop mode, and the HCCI combustion is stabilized in a state close to knock but not enabling knock to happen. Simultaneously, HCCI combustion can not cause fire so that the problem of large difficulty in controlling fire of a petrol HCCI engine is solved. The combustion control method is based on the knock sensor; and compared with a cylinder pressure sensor, cost is low, and reliability is high.

Description

technical field [0001] The invention relates to the technical field of internal combustion engines, in particular to a method for independent closed-loop control of HCCI combustion sub-cylinders based on a knock sensor. Background technique [0002] Homogeneous mixture compression ignition (HCCI) combustion is an efficient and clean combustion method. Compared with traditional spark ignition gasoline engines, HCCI engines have the potential to reduce fuel consumption by 15% to 20%, reduce NOx emissions by 90% to 99%, and have no soot (PM) emissions, completely solving the trade-off between NOx and PM in internal combustion engine emissions. Mutually exclusive (Trade-off) relationship, applied to automotive power to meet increasingly stringent fuel economy and emission regulations. However, HCCI combustion is too sensitive to engine operating conditions (cooling water temperature, intake air temperature, engine speed, fuel quality, etc.), and ignition and stable combustion c...

AI Technical Summary

Problems solved by technology

[0006] The present invention provides a method for independent closed-loop control of HCCI combustion cylinders based on a knock sensor to overcome the difficulty of HCCI combustion control and the cost of cylinder pressure sensors due to the use of cylinder pressure sensors for closed-loop control of HCCI combustion in existing demonstration technologies High, poor reliability, major changes in the engine combustion system, complex ECU control algorithms, and poor industrialization feasibility

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