Secondary adjustable boosting control system and control method thereof

Abstract

The invention discloses a secondary adjustable boosting control system. The secondary adjustable boosting control system comprises a high-pressure booster with a variable-section spray nozzle, and a low-pressure booster, which are connected in series, wherein the low-pressure booster comprises a low-pressure air compressor and a low-pressure turbine; a low-pressure intake by-pass valve and a low-pressure exhaust regulating valve are respectively arranged on by-pass pipelines of the low-pressure air compressor and the high-pressure turbine; the high-pressure booster comprises a high-pressure air compressor and a high-pressure turbine; and the high-pressure turbine is equipped with the variable-section nozzle and a high-pressure exhaust regulating valve is arranged on a by-pass pipeline connected in parallel with the high-pressure turbine. The invention further discloses a control method of the control system, and can realize supercharge pressure adjustment of a diesel engine at different altitudes and under different working conditions through controlling the opening and closing, as well as the opening degree, of all valves and utilizing the MAP value to achieve adjustment in a negative feedback mode so as to achieve the goal that the power of the engine at the altitude of 5,500 calibration point restores to 90 percent of the calibration point under the plain condition.

Description

technical field [0001] The invention relates to the technical field of engines, in particular to a two-stage adjustable supercharging control system and a control method thereof. Background technique [0002] As altitude increases, atmospheric pressure decreases and engine power decreases. In order to restore the power of the engine at an altitude of 5500m to reach the target of 90% of the plain power, the pressure ratio of the compressor should be at least 4.8 within the range from the maximum torque point to the calibration point. If a single-stage supercharging scheme is adopted, there is currently no compressor in the world that can meet such a high pressure ratio and flow range requirements, so a two-stage adjustable supercharging is required. [0003] However, most of the current two-stage supercharging control systems are aimed at various working conditions at fixed altitudes, and there is a large difference in altitude for different regions. When the matching point ...

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Problems solved by technology

[0003] However, most of the current two-stage supercharging control systems are aimed at various working conditions at fixed altitudes, and there is a large difference in altitude for different regions. When the matching point of the two-stage supercharging design is selected as an engine in a plain area, the air density will drop rapidly when it operates in a plateau area. , the engine power will decrease accordingly

When the matching point of the two-stage supercharging design is selected as the engine in the plateau area, when it is running in the plain area, the emission performance of the engine at low speed is difficult to guarantee.

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