1

PREVENTING COMMON RAIL PROBLEMS

2

HOW DOES A DIRECT FUEL INJECTION WORK?

The fuel is pressurized.

The common rail injects the fuel

directly into the combustion chamber.

This allows the fuel to burn more

efficiently.

3

WHAT ARE THE ADVANTAGES OF A DIRECT FUEL INJECTION SYSTEM?

Low fuel consumption

Reduced emissions

High Power Output

4

HOW DOES A COMMON RAIL QUALITY AFFECTS THE VEHICLE’S PERFORMANCE?

Eventual common rail failure can block the entire vehicle or even set it on fire.

5

Preventing common rail problems starts with the right manufacturing:

1. Design

2. Steel Selection

3. Forging Process

6

1. HOW DOES A COMMON RAIL PRODUCT DESIGN AFFECT ITS QUALITY?

Defects in the heading manufacturing process:

A poor design can create defective folding or buckling on the joining points between the pipe and the injectors. To secure the perfect performance of the common rail, the exact heading and upsetting parameters must be determined prior to manufacture, in particular during the design process.

Pressure and temperature fluctuations

Excessive fuel spread in the common rail occurs if the component’s design is not proportional to the desired fuel volume and pressure level. To prevent this problem, the exact dimensions of length and section diameter should be determined in the very first stage of the design.

7

2. WHAT ARE THE REQUIRED MECHANICAL PROPERTIES OF STEELS SUITABLE FOR THE MANUFACTURING OF A COMMON RAIL?

Excellent internal pressure resisting property

It is important that the material resists internal fatigue excellently since the component endures cyclical rapid loading and unloading of highly pressurized fuel on starts and stops and constant pressurized fuel flow while operating.

Vibration fatigue resisting property

To consider resistance to vibration fatigue is essential while selecting the right material, since the common rail  as a part of the diesel direct injection is a subject to vibrations.

Cavitation resisting property

Cavitation is bubble forming on low-pressure areas and implosion on high-pressure areas. The diesel direct injection has both low- and high-pressure fuel flows (low-pressure flow from tank to pressure valve is where bubbles form and high-pressure flow from pressure valve to common rail is where bubbles implode).

8

3. HOW DOES FORGING IMPACT THE PERFORMANCE OF A COMMON RAIL?

Strength

When forged, the common rail is made of stainless steel and consists only of one piece which eliminates the risk for cracks and leakages. Additionally, forging strengthens the material by closing empty spaces within the metal while deforming and shaping it with localized compressive forces.

Resistance

Nowadays the common rail for gasoline direct injection needs to be manufactured from high-quality metal to handle pressure and resist to corrosion, caused by the fuel flow. The engines have to comply also with the regulations for emission control of Euro 6 standards. Only hot forged steel offers resistance and reliability that go hand in hand with the reduction of emission of gas and particles.

9

3. HOW DOES FORGING IMPACT THE PERFORMANCE OF A COMMON RAIL?

Sophisticated geometry

Modern gasoline engines are smaller and lighter which increases fuel internal pressure and requires common rails with complex shape. Hot forging offers a vast variety of shapes and sizes that can be achieved with high-quality equipment as forging hammers, mechanical presses, screw presses and other tools. Best expertise in defining end-of-forging temperature, cooling and trimming parameters for most precise geometry is a must.

10

THANK YOU!

For more industrial insights follow us on:

www.farinia.com