Nowadays, there are more and more applications of small-engine turbocharged engines in automobiles. Its biggest advantage is that it can greatly increase the power and torque of engines without increasing the engine displacement.But turbochargers also have big drawbacks: at low speeds, they are underpressurized and the turbines are sluggish.At high speed, there will be supercharging.In order to overcome such shortcomings, bypass valve was designed on the supercharger to control the supercharger pressure.

I. working principle of bypass valve turbocharger

In high speed, high load turbocharger bypass valve is opened, the part of the waste gas by the bypass valve directly into the exhaust pipe, put off part of the exhaust gas, turbine speed decreased, thus to control the charging pressure.

There are two kinds of control methods of bypass valve turbocharger. One is mechanical (vacuum) control, which is usually used in truck diesel engines.The other is electronic control, usually used in cars.

Structure and working principle of mechanical control bypass valve type

The mechanical control bypass valve mainly consists of control air chamber, pull rod, bypass valve and so on.The pressurized gas on the left side of the diaphragm in the bypass valve actuator.

1, when the engine is low speed running, the compressor outlet pressure is low, in the role of the return spring, by-pass valve shut down, all through the supercharger exhaust from the engine turbine side, so as to improve the speed of the turbine, can produce a larger intake boost pressure, increase the volume, improve the engine performance at low speed.

2, when the engine high speed operation, pressurization blend gas pressure after more than a specified value, pressurized gas will exhaust the jacking of diaphragm actuators, drives the by-pass valve rod movement, open the exhaust bypass valves, and so not part of the exhaust gas turbocharger turbine through side, from the exhaust channel directly people atmosphere, reduce turbine inlet flow rate, pressure reducing, turbocharger speed dropped, reduce the supercharging pressure.

Electronic control bypass valve type structure and working principle

The opening and closing of the exhaust bypass valve is controlled by the electromagnetic valve controlled by the pressurized pressure controlled by the ECU.The working condition of engine electronic control unit ECU monitoring, comparing with internal preset parameters, thus to control the opening time of electromagnetic valve, so as to achieve the change of exhaust bypass valve opening, flux control exhaust, precisely the purpose of adjusting the charging pressure.

Iv. Notes for use of bypass valve turbocharger:

1. The setting and verification of the spring pre-tightening pressure in the bypass valve actuator are carried out on the specially set and calibrated equipment of the manufacturer, and the user cannot adjust or change it at will.

2. Do not use the push rod and other parts installed outside the bypass valve supercharger assembly as handles to move the supercharger assembly, so as not to affect the sensitivity and reliability of the bypass valve actuator.