Spark ignition in IC engines during cold-start conditions

Replies

• 

  Keerthivasan Ravisankar

  The spark plug is quite simple in theory: It forces electricity to arc across a gap, just like a bolt of #-Link-Snipped-#. The electricity must be at a very high voltage in order to travel across the gap and create a good spark. Voltage at the spark plug can be anywhere from 40,000 to 100,000 volts.
  

  The spark plug must have an insulated passageway for this high voltage to travel down to the electrode, where it can jump the gap and, from there, be conducted into the engine block and grounded. The plug also has to withstand the extreme heat and pressure inside the cylinder, and must be designed so that deposits from fuel additives do not build up on the plug.​

  ​

  ​

  ​

  Spark plug by default has the above mentioned sophistication.... It is quite difficult to achieve what you say....​

  ​

  Refer​

  ​

  #-Link-Snipped-#​

  ​

  ​
• 

  ISHAN TOPRE

  Gurjap

  In the lands of ice and snow, and even in some parts of India, it gets difficult to start engines. I have seen pictures of people lighting fires beneath their engine blocks just to get it running. And I'm thinking, why not just increase the amount of energy delivered by the spark plug to the gasoline? Is there any practical difficulty with that?
  
  PS. I realize, of course, that the voltage across the spark plug terminals would remain the same, because it is, after all, connected to the battery. But surely, some electrical manipulation using capacitors and op-amps and such would enable us to boost voltage for an instant or so?

  People use Ethanol+petrol to decrease ignition point of fuel rather than increase energy of spark. Quite convenient.
• 

  Gurjap

  #-Link-Snipped-# exactly! I am working on something related to gasohol, and I'm fishing for any ideas that might shoot it down
  
  #-Link-Snipped-# thanks for the link buddy 😀. The folks at howstuffworks see to the needs of high school kids, though. I'm going to follow up on this thread.
• 

  CE Designer

  Issue

  People use Ethanol+petrol to decrease ignition point of fuel rather than increase energy of spark. Quite convenient.

  Any disadvantages to this? Or is it really that simple 😐
• 

  Ramani Aswath

  Gurjap

  In the lands of ice and snow, and even in some parts of India, it gets difficult to start engines. I have seen pictures of people lighting fires beneath their engine blocks just to get it running. And I'm thinking, why not just increase the amount of energy delivered by the spark plug to the gasoline? Is there any practical difficulty with that?
  
  PS. I realize, of course, that the voltage across the spark plug terminals would remain the same, because it is, after all, connected to the battery. But surely, some electrical manipulation using capacitors and op-amps and such would enable us to boost voltage for an instant or so?

  The problem is not that the petrol-air mix does not ignite. The spark has a far higher temperature than the ignition point. Increasing that energy will be just wasteful. The problem is that petrol has a very low vapour pressure at low temperatures. It just does not evaporate. There is not enough fuel vapour to burn. You may be better off providing a warmer for the carburettor using a safe Peltier effect device or some such.
  The other option is to provide a different petrol composition for cold weather. If such a petrol is used in warm weather you will end up with a vapour lock in the fuel pipe.
  
  I am afraid that this gets you coming and going. There is no simple solution.
• 

  Gurjap

  well, what can I say? Bioramani nails it.
• 

  zaveri

  maybe you can still try out the method of connecting a capacitor in series with the spark plug. the capacitor need'nt be mounted on the engine.
  
  sometimes the problem of starting an engine during cold seasons is not just related to petrol and spark plugs alone. the low ambient temperatures sometimes affects the starter motor coils
• 

  ISHAN TOPRE

  Apart from Gasohol mix and other fluids (viscosity of oil) problems, the aspect may relate to battery.
  Battery as we all know, do not work properly in cold conditions.
  
  In modern day vehicles, chokes are provided if you are finding it hard to start your vehicle. Chokes enrich air: fuel ratio and helps it ignite fast. If you are thinking to automate the working of choke, then you should refer to some models of mopeds. I think Scooty has automated its choke in its Pep+ model.
  
  So, basically if you seek alternatives for making battery function in cold ambient temperature, you may head towards a practical solution.
• 

  Sughosh Deshmukh

  bioramani

  The problem is not that the petrol-air mix does not ignite. The spark has a far higher temperature than the ignition point. Increasing that energy will be just wasteful. The problem is that petrol has a very low vapour pressure at low temperatures. It just does not evaporate. There is not enough fuel vapour to burn. You may be better off providing a warmer for the carburettor using a safe Peltier effect device or some such.
  The other option is to provide a different petrol composition for cold weather. If such a petrol is used in warm weather you will end up with a vapour lock in the fuel pipe.
  
  I am afraid that this gets you coming and going. There is no simple solution.

  sir,
  what if we try to make some different assembly for making the fuel warm by using resistances or some electrical gadgets...
  the increase in temperature of the fuel can solve the problem....
• 

  zaveri

  Sughosh Deshmukh

  sir,
  what if we try to make some different assembly for making the fuel warm by using resistances or some electrical gadgets...
  the increase in temperature of the fuel can solve the problem....

  if fuel temperature is increased, then don't you think it would detonate , resulting in disastrous consequences
• 

  Sughosh Deshmukh

  zaveri

  if fuel temperature is increased, then don't you think it would detonate , resulting in disastrous consequences

  yea #-Link-Snipped-# your point is correct
  it will detonate if the temperature rises above its flash point or fire point.
  but if we try to maintain it below the flash point and then let it for processing it further, then i think it would be quite effective.....