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คำตอบที่ 3
สาเหตุการเกิด backfire และวิธีแก้ แปลกันหน่อยครับแต่ไม่ยาก
Check point before the installation
◎ Checking The Emission
Under the operating with Gasoline, the Emission Value - Lambda(λ), CO, HC.,- should be checked by
some kinds of Automotive Emission Analyzer. At this time, if these value are not normal one, you have
to check IG Plug, Wiring, Distributor-cap and Rotor.,etc. And replace with new parts or repair them,
when the engine are operating in normal conditions, Installations should be done.
2. Back Fire Prevention
When the engine is starting with LPG, more quantity of Air than the theoretic A/F ratio(15.7:1) is supplied to engine. In this time, this unbalanced mixture(Air & Gas) is not perfect-burning in the combustion chamber.
But there is a imperfect burning in the box of air-cleaner.
At the same time, it makes a heavy sound. We call it Back Fire.
There are two kinds of factors which may happened Back Fires in LPG Vehicles.
◎ When the Air/Fuel(Gas) Ratio is not suitable for engine-requirements.
When you accelerate impatiently or change to higher gear at higher RPM rapidly ,
you may meet with Back Fire due to a little shortage of supplying Gas at this moment.
For prevention against Back fire, ECU should be installed and a precise mixer should be made according to
the outdiameter of inlet-housing of throttle body/carburetor and displacement(cc).
And Venturi-diameter of mixer is decided by the displacement(cc).
According to the driving conditions, engine need the fuel-control which are suitable for the Air-quantity
for the purpose of maintaining the optimal engine torque and reduction of fuel consumption & exhaust gas.
The optimal quantity of mixer(Air/Gas) controlled by ECU is supplied to the engine.
Equipped with Oxygen sensor and Catalytic converter on MPI engine only is enable to install ECU.
In Korea, our ECU are occupying 80% more of local market-share continuously its establishment.
Especially, you may meet with Back-Fire with manual transmission than automatic transmission vehicles.
◎ When the Gap of Ignition-plug is not suitable for engine-requirements.
In case of the inadequated gap of spark plug, Back-fire may will be happened also.
Generally, when the using of non-leaded gasoline, the gap is 1.1mm.
In case of using the leaded gasoline and LPG, the gap is 0.75~0.80mm.
The gap of Ignition-plug should be checked before the installation of LPG Kits.
For the better performance of Fuel Consumption in LPG vehicles,
Venturi-diameter on Mixer should be decided by their engine displacement.
Ex) 1,300~1,600cc : ∮23 1,600~2,200cc : ∮25
2,400~3,600cc : ∮27
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back fire แก้ไม่ตก
