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This is an example of comparative analysis of five
types of FIR with the same capacity, but different shapes.
FIR performance requirements have become increasingly high recently due to design changes to the FIR, including the elimination of the fuel return system and pulsation damper. In particular, it is known that the pulsation (the fuel pressure fluctuation) generated when the injectors emit a jet of fuel leads to the dispersion of the fuel quantity emitted to the engine, which further causes lower fuel efficiency and an increase in emission gas.
In our company, we have focused attention on the deflection of the FIR as a solution
to reduce pulsation inside the FIR, and analyzed whether a difference in FIR shape
creates a difference in the ease of deflection.
The above images show the displacement distribution of various FIRs at the cross section caused by pressure generated when fuel flows through the FIR. These animations demonstrate that there are differences in deflection depending on the FIR shape, and that the L-shape FIR and the reverse L-shape FIR are more easily deflected than the other three shapes. It has been found that FIRs with the L-shape and the reverse L-shape absorb more pulsation generated when fuel is emitted than those with other shapes. |
• Structure Analysis Example 2 : Fuel Injection Rail (FIR)
- A study of stress levels when a load is applied.
* FIR is a device that uniformly supplies fuel to automobile engine fuel injectors. |
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This is an example of the analysis of an L-shape FIR
for a four-cylinder engine. The stress was analyzed as research to prevent deformation
and fracturing caused by the external pressure added when a rubber hose is attached
to the feed tube of the FIR.
The above right image illustrates the stress distribution when load equivalent
to that generated when a rubber hose is inserted into the end of the feed tube
is applied. This shows that greater stress is generated at the base of the feed
tube than at other areas. The strength of the stress, however, is within the tolerable
range, and therefore, it was confirmed that this FIR has sufficient strength as
a product. |
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