Does waste spark of 4-cycle 1-cylinder engine come at the same place as the true spark like at TDC?

Answer 1

On a v8 it will spark the negative spark at lets say 6 degrees before TDC then in the cylinder across from it the positive spark will happen 6 degrees before TDC exhaust. To answer you question yes it happends at the same time as the initial spark on the exhaust stroke. What the positive spark is doing is creating a vacuum or implosion inside the cylinder that sucks the piston up to improve power and fuel mileage. Ford used it for while but didn't want to pay royalties to Holden motor company in AUS so they droped it. The technology has kind of been buried because it has the potential to expose that an engine can run on air. If a car is preigniting or dieseling they call it you shut your car off and the engine keeps going. They put a solenoid on the carby to shut the fuel down to stop this but it still occurs even without fuel. Most mechanics will retard the timing to fix it. The real shocker is when you advance the timing further. When the key is turned off your normal spark that was negative runs on a different part of your ignition coil and produces a positive spark that is sucking the piston up. The engine is only around 6 someodd degrees before TDC so it's running as rough as guts. Now take your timing and advance as far as 80 degrees before TDC and the engine will run smoothly with no fuel going to it. IF the car's ground positive instead of negative the spark and waste spark will have oposite polarities the spark will be positive and the waste spark will be negative. ---- On a 1-cylinder engine, the waste spark comes at exactly the same place as the true spark (typically very close to TDC).