As a critical component of the gasoline and diesel direct injection, a common rail is of highly importance for a vehicle's performance. Eventual common rail failure can block the vehicle or even set it on fire. Preventing common rail problems starts with the right manufacturing.

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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.
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3. WHAT ARE THE ADVANTAGES OF A DIRECT FUEL INJECTION SYSTEM?
 Low fuel consumption
 Reduced emissions
 High Power Output
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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.
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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.
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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). 7

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.
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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.
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