Diesel engine variable-altitude boost pressure control method

Abstract

Disclosed is a diesel engine variable-altitude boost pressure control method. Through a two-level adjustable booster controller ECU, according to change of altitude, diesel engine rotation speed and loads, opening of a high-pressure stage VGT vane of a two-level adjustable booster and opening of a high-pressure stage turbine regulating valve and a low-pressure stage turbine regulating valve are controlled in real time, optimal control is conducted on boost pressure in a variable-altitude and variable-working-condition mode, and the purpose that in the 0 m-5500 m altitude range, all performance indicators of a diesel engine are always kept the same as the performance under the plain conditions is achieved. The mode that feedforward control and fuzzy PID control are combined is adopted for the diesel engine variable-altitude boost pressure control method, and the boost pressure can be adjusted in real time according to change of altitude and working conditions of the diesel engine, so that the requirements for best power performance and fuel economy in the steady state working condition and the transient state working condition are met, the objective that power of the diesel engine at the altitude 5500 m fixed point is recovered to 95% or above that on plains is achieved, turbo lag is relieved, and pumping loss work is reduced. Meanwhile, the problems of gas compressor surges, turbine overspeed, excessively high turbine-front discharge temperature and the like are avoided.

Description

technical field [0001] The invention relates to the technical field of diesel engines, in particular to a method for controlling boost pressure of diesel engines at variable altitudes under plateau conditions. Background technique [0002] The plateau area above 2000m in my country accounts for about 37% of the country's land area, and the Qinghai-Tibet Plateau with an average altitude higher than 4000m accounts for 25% of the country's land area. When the diesel engine is running on a plateau, as the atmospheric pressure decreases, the intake air volume decreases, resulting in a decrease in power and economy, and an increase in exhaust temperature. In order to restore the power of the diesel engine at an altitude of 5500m to reach the target of plain power, the total pressure ratio of the supercharger must be at least 4.8 in the range from the maximum torque point to the calibration point. Therefore, in order to meet the high-altitude power requirements of the diesel engine...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the technical defects existing in the existing high-altitude supercharging system, the present invention proposes a diesel engine variable-altitude supercharging pressure control method. The control method of the system adopts the combination of feedforward control and fuzzy PID control. Real-time adjustment according to the change of altitude and diesel engine working conditions, taking into account the high pressure ratio and wide flow rate, meeting the requirements of the best power and fuel economy under both steady state and transient working conditions, and achieving power recovery at the calibration point of the diesel engine at an altitude of 5500m To the target of more than 95% of the plain, the problem of turbo hysteresis is alleviated, the loss of pumping work is reduced, and problems such as compressor surge, turbo overspeed, and excessive exhaust temperature in front of the vortex are avoided.

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