The combustion that takes place inside your car's engine requires incredibly high levels of temperature and pressure. Yet if either of those factors grows too great, problems may ensue in the form of detonation. Detonation — also known as engine knocking — occurs when the air-fuel mixture inside your cylinder combusts spontaneously.
Because such spontaneous combustion usually occurs at an inopportune time, it can greatly hamper your car's performance. In addition, the incredible amounts of force generated by detonation can damage pistons, bearings, gaskets, and other engine components.
The longer the problem goes on, the more destructive its effects will be. Fortunately, car and truck owners can employ a variety of strategies to help keep detonation at bay. If you would like to learn more about this all-too-common engine problem, keep reading. This article takes a closer look at three effective strategies for preventing engine detonation.
1. Use a Higher Octane Fuel
As you likely know, automotive fuels receive octane ratings. Among other things, these ratings express the amount of compression a fuel can withstand before it combusts. The higher the octane, the higher its resistance to compression. Standard gasoline has an octane rating of 87.
For most cars, this should be sufficient. Yet if you experience regular detonation — or if you drive a performance sports car with a higher-compression engine — you may benefit from switching to a fuel with a higher octane rating. The same holds true for those who drive cars with forced-induction air-intake systems such as superchargers or turbochargers.
2. Have Your Ignition Timing Checked
In order to produce the greatest amount of energy, engine combustion must be timed to occur just as gases inside of the cylinder reach their most compressed point — in other words, at the very moment the piston finishes its compression stroke. Achieving this timing can be tricky, given the high speeds at which an engine operates.
To make matters even worse, your spark plugs actually have to fire a split second before the moment of maximum compression. Simply put, it takes a small amount of time for the spark to actually set the gases on fire. This duration goes by the name of the ignition advance and is a crucial part of engine efficiency.
Yet detonation often ensues when an ignition advances too far — that is to say, when the spark plugs fire too soon. The spark creates additional pressure inside of the cylinder. Couple with the pressure of compression, the spark's pressure often causes the fuel to ignite, leading to detonation. Eliminating this problem involves having a technician check and reset your ignition timing.
3. Don't Use an Excessive Compression Ratio
Engines are often evaluated in terms of their compression ratio. This term simply denotes the difference between the volume of combustion gases at the start of the compression cycle and at the end. Generally speaking, the greater the compression ratio, the more energy will be generated when the fuel combusts.
Yet compression ratios have distinct limits. At a certain point, too much compression will increase the pressure — and hence the temperature — of the fuel to the point that it spontaneously combusts. Since the compression ratio of an engine doesn't change much after it has been built, this problem shouldn't affect most cars.
Yet for hot-rod types who enjoy tweaking their engine for maximum performance, excessive compression ratios represent a real threat. Switching to a higher octane fuel may be enough to offset the compression ratio. Yet if the compression ratio is too high, the engine may need to be retooled in order to bring it back down within safe limits.
Detonation poses a serious threat to a car's engine. To learn more about the ways in which you can help prevent detonation, please contact the automotive pros at Morrison Automotive & Truck.