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How Well Do You Know Your Engine?

car engine partsThere’s more than meets the eye when it comes to the engine in your vehicle. You may be aware that the engine is responsible for creating the energy to move the vehicle forward, but how well do you really know how it works? What’s the difference between a diesel and gas engine, a four-cylinder versus a V6, or a two vs four-stroke engine? Learn more about how each of the many components and parts that work together to get the vehicle into motion as well as the difference between them, so you can get to know your engine.

Gas and Diesel-Powered Engines

While both engines function on applying the intake, compression and power, exhaust, and air to fuel proportions, each engine functions differently. Diesel-powered engines take air into the combustion chamber while gas-powered engines take in both air and fuel. Power and compression differs as well. Each engine compresses air into a small area, creating an explosion, though from there, their functions diverge. In gas engines, the spark plug ignites the air and fuel mixture, forcing the piston down. In diesel engines, however, as the piston reaches the top of the compression stroke, the air is compressed significantly, increasing in heat, and igniting the diesel fuel deposited by the fuel injectors. Diesel engines are able to operate on a wide range of air to fuel ratio whereas gas engines are limited.


The average small to midsize sedans commonly use a minimum of four cylinders to function, though some vehicles, such as high-performance cars, semi-trucks, and other larger vehicles may be equipped with as many at twelve cylinders. More power is produced based on the number of cylinders. While this sounds ideal, the increase in cylinders results in a demand for more fuel, which may impact your wallet over the course of time. Additionally, vehicle models with a higher number of cylinders compared to their lower cylindered counterparts often cost more overall. A four-cylinder economy engine is an excellent choice for the daily commuter but those who drive in more difficult terrains may benefit from an increase in cylinders based on the power that the vehicle demands from the engine.

Two Stroke vs. Four Stroke Engine

The word stroke, as it relates to a combustion engine, refers to the movement of the piston. The number of strokes it takes to complete a combustion cycle from start to finish is equal to the number of strokes. The strokes in a four-cycle engine in each cycle are intake, compression, combustion, and finally, exhaust. For example, a four-stroke engine requires four movements of the piston with controlled openings at the top to let fuel in and one to allow the exhaust from the explosion out:

  1. Intake – the first stroke made in a downward position where it takes in a combination of air and fuel.
  2. Compression – an upward motion that compresses the mixture.
  3. Combustion – a downward motion, as a result of the explosion from the fuel igniting.
  4. Exhaust – the piston moves upward again to force out any exhaust from the engine.

To keep pistons moving smoothly, oil is required to circulate around the base of the piston and lubricate the cylinder as the piston moves.

A two-stroke combustion system has pistons with controlled ports on each side of the cylinders, one as the transfer port, the other as an exhaust port. As the piston strokes upward, the air and fuel combination is compressed while more air and fuel is being pulled into the chamber. As the piston strokes down, it passes the outlet for exhaust and releases it at that time. As it continues in a downward stroke, it allows the air and fuel mixture from the chamber into the area above it, which is not completely clear of exhaust. As the piston starts the cycle over, it not only compresses the mixture, it also allows the some of the mixture out via the exhaust outlet. Because the area below the piston contains the fuel mixture, oil has to be added to the fuel, in order to keep the system lubricated. Although a two-stroke engine weighs less than a four-stroke and has fewer parts, it produces more emissions and results in lower fuel efficiency.

Engine Trouble

The internal combustion engine is the result of the combustion of fuel, that produces heat. The cooling and lubricating of internal components greatly increases the longevity of your engine. In other words, frequent oil changes and other engine maintenance is beneficial to the life of your vehicle. When an engine gets hotter than intended, it can cause a strain on bearings, valves, and the pistons. The cylinder heads that hold the intake and exhaust valves are a commonly damaged part due to poor maintenance and frequent overheating.

Your engine is one of the most important components in your vehicle and must be maintained properly. Frequent oil changes and fluid flushes at regular intervals help keep your engine performing at its very best. The key to a longer lasting vehicle is maintenance and Sun Auto Service is your key to maintenance services! Our knowledgeable Service Consultants can help guide you to ensure your vehicle performs at an optimal level. Two-stroke or four-stroke, four cylinders or V8, gas or diesel engines each are unique and are our specialty. We’ve been in business since 1978, employ ASE Certified Technicians, and are proud of our A+ rating with the Better Business Bureau. Don’t take our word for it though, stop into any of our many service centers near you and experience quality auto care and maintenance for yourself.