Why Jazz got 8 spark plugs?!

[Eng40765]

Sent my sister car for servicing, got to top up money for 4 extra spark plugs. How come Jazz got 8 sparks?! Anyone knows the advantage of more cylinder/sparks plugs?!

[Civic6656]

Sent my sister car for servicing, got to top up money for 4 extra spark plugs. How come Jazz got 8 sparks?! Anyone knows the advantage of more cylinder/sparks plugs?!

 

iDSI models all 8 sparkies. Formal City also.

It is supposed to give better combustion for fuel economy.

iVTEC models have only 4 sparkies.

Edited November 9, 2010 by Civic6656

[Civic3106]

Sent my sister car for servicing, got to top up money for 4 extra spark plugs. How come Jazz got 8 sparks?! Anyone knows the advantage of more cylinder/sparks plugs?!

 

iDSI only lah but no iVtec

[ER-3682]

I remember some older Mercedes V6 & V8 also got 2 spark plugs per cylinder,help to complete burning less pollution,but latest Mercedes is back to 1 spark plug per cylinder,maybe the engineer think it is not needed after all.!

[marwing]

your Jazz's engine must be DSI technology.

 

go google for Dual Sequential Ignition (DSI) and you will know why.

[Crazecow]

I remember some older Mercedes V6 & V8 also got 2 spark plugs per cylinder,help to complete burning less pollution,but latest Mercedes is back to 1 spark plug per cylinder,maybe the engineer think it is not needed after all.!

 

I don't think new engines these days need dual spark plugs to get good combustion (even old ones don't need). Tuning is what is needed to get good combustion.

[Kangadrool]

Alfa Romeo also had twin sparks before, but now all single sparkie.

[Krado]

Anyone knows the advantage of more cylinder/sparks plugs?!

 

Simple. More = Better.

[Minikong]

wah v8 in disguise!

[Jl1500k]

but need to pay more for the "better"

 

 

[Krado]

but need to pay more for the "better"

 

Simple. Cheap = not good. Good = not cheap.

[Happily1986]

it is not about having more. Thats not the logic. The idea of having more than one is to allow for a more even combustion of the air-fuel mixture. Without going into fluid mechanics, the air-fuel mixture swirl alot in the piston. When the spark plug ignites, not all of the entire mixture ignites. When this happens, there is a loss of would be compression and thus power.

 

At low engine rpm, the swirl is lesser and mixing is less pronounced. Hence the spark plug activate one at a time. The first one to come online is the one nearest to the inlet valve. In theory, the bulk of the mixture should be at the region closest to the intake valve. The second valve comes online near the end of the exhaust phase. This will ignite all the unignited air fuel mixture which would otherwise escape and be lost through the exhaust.

 

At high rpms, the swirl is maximum and both spark plugs fire at the same time. Because the intake and exhaust valves open and close so quickly, it doesn't make a difference whether the twins rise to the occasion one at a time. In fact because the opening and closing are so fast, the piston is virtually blurring to become semi open. Thus, both should fire as fast as possible If you think about it, there is a limit to the angular frequency of firing.

 

For an equivalent volume of air-fuel mixture introduced, more efficient extraction of mechanical work i.e. compression would be made out at low revs. At high rpms due to the the time delay of the ignition timing becoming an issue, the efficiency of the work extraction decreases. This to me, explains why people find that iDS-I peter out at high speeds.

[Itsec]

http://asia.vtec.net/Series/FitJazz/lseries/

[Furrynadz]

too lazy to design EGR use twin spark

[Happily1986]

what is EGR?

[Friendstar]

http://asia.vtec.net/Series/FitJazz/lseries/

 

 

the person who wrote this article is a genius or wat.

 

super zai.

[Itsec]

the person who wrote this article is a genius or wat.

 

super zai.

 

yup... he wrote alot of articles for different models of honda... there should be one for ody also..