Maintaining an automobile can be a daunting task given the vast number of components that have to work in close conjunction with one another. None of these components hold quite as important a place as your engine. Even a relatively small engine problem can have an adverse effect on everything from your gas mileage to your car’s performance.
One frequent source of engine troubles goes by the name of pre-ignition. Pre-ignition can lead to a number of devastating problems if not corrected in time. If you would like to learn more about pre-ignition, its causes, and how it can be corrected, read on. This article will provide a useful introduction to the subject.
What is Pre-Ignition?
A basic overview of engine mechanics will help you understand the problem of pre-ignition. During normal operation, a mixture of fuel and air enters the car’s cylinders. At a predetermined time, spark plugs ignite this mixture. The force of ignition then causes the piston to depress and the crankshaft to turn, thus providing the car with mechanical power.
As its name implies, pre-ignition happens when an engine ignites fuel sooner than it should – in other words, before the spark plugs have fired. As a result, the engine produces a significantly reduced amount of power. If allowed to persist long enough, pre-ignition can lead to damage inside of the engine.
What Causes Pre-Ignition?
Pre-ignition may stem from a number of causes. Overheating sparkplugs are one of the most frequent sources, however. When a sparkplug overheats, its electrode often reaches a temperature where it literally glows with heat. Such hot spots trigger combustion before the piston has reached the appropriate point in its compression stroke.
Another cause of pre-ignition involves excessive carbon buildup inside of the cylinder. This buildup can form a heat barrier, making it more difficult for the cylinder to diffuse the heat of combustion. As the engine continues to heat up, eventually the carbon buildup retains enough heat to cause premature combustion.
Pre-ignition may also stem from problems with the pistons. A damaged or corroded piston may no longer provide an adequate barrier to engine oil. As the oil enters the cylinder, it mixes with the gasoline. This diesel-like mixture has a higher cetane number – hence a higher volatility – than gasoline itself, meaning it will combust at lower temperatures.
Finally, pre-ignition may occur if the air-to-fuel ratio in your engine skews too far toward the air side – an imbalance commonly referred to as lean fuel. Too little fuel in the mix puts your cylinders at a greater risk of overheating.
Though it may seem contradictory, fuel actually helps to keep your engine cool. As liquid gas enters the cylinder, it evaporates, thus absorbing some of the cylinder’s latent heat. Lean fuel simply doesn’t have enough gasoline to perform this vital function.
What are the Effects of Pre-Ignition?
As noted above, pre-ignition ultimately damages your engine. This damage usually begins with the sparkplugs. Overheating will leave dark carbon deposits – known as fouling – on the electrodes. If the problem continues, the porcelain parts of the sparkplug may even begin to melt or fuse together.
Soon the pistons themselves will begin to suffer damage. The lower heat tolerance of the pistons puts them at a greater risk than other internal components, such as cylinder heads or the engine block. The aluminum crown of the piston will develop holes in response to the heat and pressure being exerted by the pre-ignition forces.
Eventually pre-ignition will completely compromise your engine, leaving you with a nonfunctional automobile. For that reason, you must be proactive about catching the problem before it escalates. The best way to do this involves having your car regularly inspected by a professional. For more information, please don’t hesitate to contact DeMers Automotive.