TPFC: Transient Power Fuel Control System

TPFC: How Transient Power Fuel Control System Works, Explained

What is TPFC?

The term TPFC stands for Transient Power Fuel Control system. This system uses a constant-choke carburetor. The most prominent feature of this type of carburetor is that it increases the engine speed without any jerks. In this system, the throttle valve creates the vacuum which opens a slide. It eventually controls the air-fuel ratio through a tapered jet.

TPFC: Transient Power Fuel Control System badge
TPFC: Transient Power Fuel Control System badge

Most bikes use ‘Constant Velocity’ carburetor. This type of carburetor maintains constant velocity at the Venturi. This produces an optimum air-fuel ratio. However, this type of carburetor has a slight lag/delay when the rider opens the throttle suddenly.



How TPFC Works?

This is where Transient Power Fuel Control system comes into play. Its nozzle mechanism sprays petrol when the rider opens the throttle suddenly. Thereby, it instantly revs the engine. This increases the throttle response and the engine feels livelier. However, this increases the emission levels. Hence, TPFC was consequently discontinued. Later, the fuel injection technology replaced the carburetor.

Transient Power Fuel Control System bike
Transient Power Fuel Control System bike

If the rider opens the throttle without needing it; activates the Transient Power Fuel Control system. And thus, it will accidentally waste some fuel. Typically in TPFC, an accelerator pump injects more fuel to compensate for the lean air-fuel mixture which it generates when the rider applies sudden throttle. The pilot circuit in combination with the needle and needle jet normally has enough rich setting. So, it does not need extra enriching from the accelerator pump.



Advantages of TPFC:

Basically, the Transient Power Fuel Control system is a technology that offers dual character to a small engine. It does so by increasing the air-fuel ratio s as and when the engine needs it. This ultimately results in higher engine power/performance.

Additionally, the special feature of the TPFC (Transient Power Fuel Control System) is that it handles sudden acceleration with ease. Furthermore, Hero also provides an air-filter element which injects fresh air into the exhaust to meet emission norms.  According to Hero Motocorp, it helps to keep the environment pollution free. Thus, it makes this bike ‘eco-friendly’. Hero Motocorp employs Transient Power Fuel Control System in its Hero CBZ model.

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Read on: Air fuel ratio principle and theory explained >>

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