For most car buyers, fuel economy is the biggest factor that they have to consider. They choose between different car models, their relative sizes and features. One factor that greatly affects fuel economy is the type of engine, which, unfortunately, is not given a second thought.
A buyer mulling about power plants before an SUV dealer would usually choose the engine they are already accustomed to. But if you are really serious about fuel economy, you should study the operating costs of a diesel engine and a petrol-powered one. This way, you will clearly see which is the better option for you.
Economy and Efficiency
As an internal combustion engine, a petrol engine requires a spark plug to ignite the air-fuel mixture, which causes an explosion in the piston chamber. In contrast, the fuel in a diesel engine explodes the moment it is injected into the piston chamber simply because of the high pressure inside the above mentioned chamber.
A diesel engine needs high compression to cause an explosion in the chamber. The same high compression produces greater torque than petrol engines. More torque means better acceleration and more pulling power to carry heavier loads.
Vehicles with heavy loads use diesel engines because of the high torque. This also explains why diesel engines produce more power compared to petrol engines of the same size. At the same time, diesel engines consume up to 30% less fuel than petrol-powered cars.
Diesel’s high compression system requires more metal to be able to contain the pressures inside the engine. However, petrol engines run at hotter temperatures compared to water-cooled diesel engines. The explosion inside the engine produces more heat than that found inside a diesel engine.
Running hotter, a petrol engine has a shorter usable life compared to diesel. Additionally, the spark plug and the timing mechanism requires more maintenance for a petrol engine.
To be fair, the fuel injection system of a diesel engine does not require a carburetor and requires less maintenance, but the costs are more expensive. This means that the diesel has a longer maintenance cycle but is more costly for that.
A diesel engine running continuously at 1800 rpm can operate from 12,000 to 30,000 hours before major maintenance is called for. On the other hand, a petrol engine that is also running at 1800 rpm can operate from 6,000 to 10,000 hours between servicing.
Admittedly, there are disadvantages for a diesel engine. Chief among these is the higher engine cost. However, this is offset by diesel’s higher resale value. Another factor is the higher maintenance cost. This is a supply and demand issue because there are fewer garages with the equipment to maintain diesel engines.
Diesel engines also have performance issues, chiefly that these have a hard time starting in cold climates. Petrol engines have a spark plug to light up the explosion in the chamber, which diesel engines do not have.
Compared to petrol engines, diesel engines have a different method of internal combustion. The relative advantage of a diesel engine does not necessarily translate to an absolute choice when it comes to vehicle power plant. However, diesel engines are worthy of consideration when choosing a vehicle.