Device
The control valve is located in the main muffler. When the exhaust gas pressure overcomes the spring force, the control valve opens depending on the exhaust gas pressure.
Job (see fig. 2.27)
Pic. 2.27. Scheme of operation of a two-stage injection control system: 1 - the control valve is closed; 2 - the control valve is open; 3 - exhaust gases
Control valve closed (low engine speed).
Since the pressure in the main muffler is low, the control valve is closed. Consequently, the exhaust gases do not pass through the bypass and the exhaust noise is reduced by the main muffler.
Control valve open (medium and high engine speeds).
The valve opens with increasing engine speed and muffler backpressure. This allows more exhaust gases to pass through the bypass, thus significantly reducing back pressure.