Pulse type turbocharign
  1. In Pulse-type Turbocharging system, it makes full use of the high pressure and temperature of the exhaust gas during the blowdown period and rapidly opening of the exhaust valve.
  2. The Exhaust gas reaches the cylinder at extreme velocity as pressure energy is transformed into kinetic energy to form a  pressure wave or pulse in the exhaust Pipe and it eventually lead to the turbocharger turbine.
  3. The exhaust pipe so constructed in small diameter is quickly pressurized and boosted up to form pressure pulses or waves.
  4. The Pressure wave reached to turbine nozzle and further expansion takes place.
  5. Some interference may exist between exhausting and scavenging among cylinders.
  6. The exhaust pipes are grouped or tuned such as to prevent any possibility of exhaust going into another cylinder during the scavenging period.
  7. The pipes are organised in lesser diameter to increase up pressure pulses and used in little lengths that are straight to prevent energy losses.
  8. No sharp bends in the pipe are provided, and neither is any obstruction on the exhaust pulse flow.
  9. The number of exhaust branches depends on a firing order, number of cylinders and turbocharger design. 
Pulse type turbocharging block diagram

Advantages of Pulse-type Turbocharging system

  • At reduced load and reduced speed, more efficiency can be seen.
  • At a low load, it does not require any form of scavenging assistance.
  • During load change, good turbocharger acceleration and response is there.
  • High energy is available at the turbine inlet.
  • The system does not require a larger volume to accommodate the exhaust pipe inside as it does not require a large diameter manifold.

Disadvantages of Pulse-Type Turbocharging system

  • The exhaust grouping is complicated and quite complex in design.
  • Very unique sizes of exhaust pipes are required for spare.
  • Pressure wave reflection problems may be caused in some engines.
  • Poor Turbine efficiency at a very high rating
  • Firing order, number of cylinders, number of turbochargers must be considered during exhaust grouping.
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