Control method for intake and exhaust management system of supercharged engine

Abstract

A control method of an intake and exhaust management system of a supercharged engine comprises the following steps: step 1, an engine controller obtains an air flow value, an intake manifold pressure value and an exhaust manifold pressure value in the working process of the engine; step 2, the engine controller judges a working mode according to the air flow value, the intake manifold pressure value and the exhaust manifold pressure value and a vehicle working condition; step 3, the engine controller drives a throttle valve and a two-way bypass valve to work so as to eliminate surge; step 4, the engine controller drives the two-way bypass valve to work so as to improve the torque of the engine at a low speed. and step 5, the engine controller drives the two-way bypass valve to work so as to reduce the nitrogen oxide content in exhausted waste gas. By means of the design, the bypass amount of air inlet and air outlet can be accurately controlled so as to improve the anti-surge, torque increasing and emission reducing effects, and a control system is simple in mechanism and high in reliability.

Description

technical field [0001] The invention relates to an engine intake and exhaust control method, in particular to a control method for a supercharged engine intake and exhaust management system, and is particularly suitable for the intake and exhaust control method for increasing engine torque under low-speed working conditions. Background technique [0002] Diesel engines are widely used in commercial vehicles. The turbocharging systems of diesel engines currently in use usually use wastegate superchargers or variable cross-section / nozzle superchargers. Both superchargers use the exhaust gas energy from the engine to expand the turbine. After doing work, the turbine drives the coaxial impeller, and the impeller compresses the fresh air filtered by the air filter to pressurize it into the cylinder; the wastegate supercharger can passively open the bypass valve when the engine is running at high speed to direct part of the exhaust gas to the cylinder. The bypass to the post-vorte...

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Problems solved by technology

[0004] 1. When the wastegate supercharger is running at low speed, the wastegate valve remains closed. Due to the low exhaust pressure and temperature, the energy of the driving vortex to do work is less, and the rotor of the supercharger rotates slowly, resulting in an acceleration response of the engine The performance is poor, and the outlet pressure of the compressor is low, which cannot meet the air quality requirements of the diesel engine under this working condition, resulting in low engine torque at low speed

[0005] 2. In order to ensure a certain low-speed torque, when choosing a wastegate supercharger, it will prefer a low-speed performance solution at the expense of a certain high-speed performance and high-altitude capability, resulting in the engine not running in an optimal matching state under all operating conditions;

[0006] 3. The supercharging effect of the wastegate supercharger is poor when the engine speed is low, and the acceleration response of the whole vehicle is poor;

[0007] 4. The cost of variable section / nozzle supercharger is high, the application range is small, and the reliability risk of exhaust brake is high

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