19 replies to this topic

[MIGLIACARS]

Thinking outloud here.

On a wasted spark ignition system, the spark is fired every time a piston is at tdc on all 4 cylinders,

so  !!!   it wouldnt matter if the HT leads were on the wrong plugs!!!!! 

or have I missed something

[nicklouse]

Most are twin coil so you do need to connect the right pairs of plugs to the correct coil.

[Batmini]

I'm sure it could be done, but wouldn't you need a bigger coil. It would need a lot more power to fire all 4 plugs. I think that's how some 'limp-modes' work on modern cars. All 4 firing at the same time.

[Carlos W]

As long as the lead was on the same cylinder as the other one at TDC

[Steve220]

Thinking outloud here.
On a wasted spark ignition system, the spark is fired every time a piston is at tdc on all 4 cylinders,
so  !!!   it wouldnt matter if the HT leads were on the wrong plugs!!!!! 
or have I missed something

If all plugs fired at the same time, the engine would never run.

[Carlos W]

Just to confirm, the plug fires every time the piston is at TDC, so in effect It will fire on the power stroke as well as the change over between the exhaust and induction stroke. All 4 don't fire at the same time

[Dusky]

Is this even a serious question? 4 simultanious sparks..Also pretty pointless. If you want to experiment look for multispark technology.

Edited by Dusky, 14 August 2016 - 01:38 PM.

[MIGLIACARS]

Is this even a serious question? 4 simultanious sparks..Also pretty pointless. If you want to experiment look for multispark technology.

Im not sure you have read the question!!!

 

So in a 4 cylinder engine on a wasted spark system the car has 1 coil.     or it would be coil on plug!!!

 

when piston 1 reaches tdc piston 4 is 180 degrees apart also at tdc but on the exhaust stroke not compression.

but on this system both spark plugs fire 1-4,   so in theory you could swap the HT leads around on 1-4 and 2-3.

 

!!!!!!!!!!!!!!!!

[Carlos W]

 

Is this even a serious question? 4 simultanious sparks..Also pretty pointless. If you want to experiment look for multispark technology.

Im not sure you have read the question!!!

 

So in a 4 cylinder engine on a wasted spark system the car has 1 coil.     or it would be coil on plug!!!

 

when piston 1 reaches tdc piston 4 is 180 degrees apart also at tdc but on the exhaust stroke not compression.

but on this system both spark plugs fire 1-4,   so in theory you could swap the HT leads around on 1-4 and 2-3.

 

!!!!!!!!!!!!!!!!

 

As I understand it, yes

[sledgehammer]

as above 1&4 2&3 have spark at same time

 

having all spark at tdc on cyl one will  have fuel air mix firing at bdc on cyl 2&3 & vica versa

 

a lot of cars in the 90 - 2000's had wasted spark systems cheap way of doing it

 

some fuel injection systems run paired injectors firing at the same time vaux 6 cyl springs to mind

Edited by sledgehammer, 14 August 2016 - 02:11 PM.

[sledgehammer]

Is this even a serious question? 4 simultaneous sparks..Also pretty pointless.

 

Irony is great in this one  

 

any yes the question is a valid one - 2cv's run spark at the same time on all cyl's (2cyl)

[Dusky]

Is this even a serious question? 4 simultanious sparks..Also pretty pointless. If you want to experiment look for multispark technology.

Im not sure you have read the question!!!
 
So in a 4 cylinder engine on a wasted spark system the car has 1 coil.     or it would be coil on plug!!!
 
when piston 1 reaches tdc piston 4 is 180 degrees apart also at tdc but on the exhaust stroke not compression.
but on this system both spark plugs fire 1-4,   so in theory you could swap the HT leads around on 1-4 and 2-3.
 
!!!!!!!!!!!!!!!!

  it wouldnt matter if the HT leads were on the wrong plugs!!!!! 

It would still matter.And you Have Just proven that yourself.

Edited by Dusky, 14 August 2016 - 02:37 PM.

[MIGLIACARS]

I dont understand you!!!!

Please explain.....

[podifold]

To answer your question:

 

On a wasted spark system there are 2 coils. When used on a Mini one coil goes to plugs 1 and 4 and the other coil goes to plugs 2 and 3. 

 

For a full cycle of all 4 cylinders to fire (in the correct order of 1, 3, 4, 2): 1 and 4 both spark at the same time, then 2 and 3 at the same time, then 1 and 4 again, then 2 and 3 again.

 

So yes, you can swap the position of plug 1 with plug 4, OR plug 2 with plug 3 and it won't make any difference to the running of the engine.

 

[Ethel]

Wasted spark is principally about doing away with the distributor which involves mechanical bits that can wear out and fal - you get a second spark anyway, off the rotor arm, so the potential for lost energy isn't that different.

 

On a 4 cylinder engine you need a minimum of 2 coils, they're packaged together with a common +ve, but they have 2 independent -ves that are switched the same as on an electronic dizzy.

 

As the spark is actually created when the voltage gets high enough to jump the gap, the cylinder under pressure with ionised fuel droplets between the sparkplug electrodes will have less resistance and is likely to be the first, probably only, one that fires .