Modern passenger cars are produced with three types of engines: gasoline (the most mass segment), diesel (a no less popular type of internal combustion engine), and electric (the smallest segment). And that’s not counting exotics like hybrids. But disputes concerning which internal combustion engine is preferable – working on gasoline or diesel fuel. There is no special debate about electric cars and hybrids yet, due to the small number of adherents of this technology.
To understand which type of engine is better, it is worth studying the basics of their operating principle, efficiency, and other features. The latter includes the cost of both the power unit and its maintenance, plus reliability and service life. Details are here
The principle of operation of internal combustion engines
Gasoline and diesel operate on approximately the same principle. But there is a huge difference between them precisely due to the peculiarities of fuel ignition during the combustion of the fuel-air mixture.
- In a gasoline engine, the mixture of gasoline and air is ignited by the spark generated by the spark plug. The mixture fills the cylinder, is compressed, and then the spark plug gives off a spark, which causes a sudden increase in pressure, and the combustion vapor pushes the piston down. Without the spark plug, the temperature of the fuel/air mixture at compression is only 500°C. This is not enough for auto-ignition.
- Diesel engines run without the spark generated by the spark plug. They self-ignite the mixture of fuel and air at maximum pressure. Air is compressed in the cylinder to a pressure of the order of 50.9858 kg/cm², after which fuel is injected. The temperature of the compressed air alone reaches 900° C, which is sufficient for auto-ignition. The burning fuel pushes the piston.
The basic principle is the same, but because of the different approaches to the ignition of the fuel mixture, both motors have different efficiencies and will develop different power at the same volume.
Engine efficiency and power
Of course, both gasoline and diesel engines are different. Thanks to the introduction of various technologies like TDi, CRDi, MPi, and others, the efficiency and power have increased significantly relative to the basic values. Therefore, it is necessary to consider a “spherical” motor “in a vacuum”.
And here we find out a curious picture. Diesel engines have a higher efficiency, and the difference is significant – about 35-40%. This ensures the reduction of fuel consumption. The high efficiency is explained banally: the efficiency of combustion of the mixture under higher pressure.
At the same time, gasoline engines are characterized by a higher power. But to remove this power, the petrol engine will have to be revved up to 5-6 thousand revolutions. At 3 thousand rpm, the diesel will be more powerful. And all because the torque is decisive, and in diesel it is traditionally lower. It is trivially faster to gain declared power, though it is inferior to petrol in acceleration.
A car with a cheap MPi at 3-4k rpm still has the power to spare and can still be spun. And a car with TDi at the same rpm will already give out all the power reserve and will not be able to accelerate sharply. At least, the cost of such acceleration will be inadequately high, and the gasoline consumption will fall with speed.
Engine Maintenance
Which is better – a gasoline or diesel unit in terms of maintenance? And here, the clear advantage is on the side of the gasoline power unit. It can easily withstand continuous operation at over 4 thousand rpm, spare parts are quite cheap, the cost of repair is low, and it is possible to repair the car almost “on the knees”. Problems with finding a good mechanic will not occur.
Diesel units are more “capricious.” It is necessary, to begin with, the quality of fuel and the necessity of filling “winter” diesel fuel in cold weather, otherwise, there will be problems with the work of the power unit. Even experienced specialists rarely take up the repair, and the cost of such services is comparable with the overhaul of the internal combustion engine on gasoline. The owner of a diesel engine is just forced to change the oil and filters often. And problems with the fuel injection system become a real headache.
Engine life
Based on maintenance features, it seems that gasoline is better than diesel. In fact, a gasoline powertrain doesn’t mean it physically last as long as an average diesel engine. You can find diesel-powered cars on the roads with millions of miles on the road. Especially the old trucks.
On average, if an engine is well taken care of, good fuel is used, and one does not skimp on the grease and filters, resources are as follows:
- 150-350 thousand km for a petrol engine;
- 200-500 thousand km for diesel engines.
The figures, in reality, are very different. For example, the Toyota 3S-FE gasoline engine is referred to as “millionaire.” A diesel VW 2.0 TDI cab will run about 100k km before significant wear. It can be paired with the notorious BMW N47, which could not drive more than 50,000 km at its cost.
What automobile to choose – diesel or petrol?
To sum it up:
- The diesel unit is a “marathoner,” which will be better than the counterpart on gasoline in terms of consumption, cost per kilometer of mileage, and, most importantly, durability.
- The gasoline power unit is a “sprinter,” which has excellent dynamics; it is better than diesel in terms of maintenance costs, maintainability, and the ability to withstand increased speeds for a long time.
What to choose is up to you. If the car is bought for years as a “workhorse,” the diesel engine obviously wins over gasoline. And if a car is bought for personal use for driving on highways and in the city, gasoline is a clear favorite.
But to have an opportunity to drive a car, it is necessary to receive a license. And this will help the driving school “Vector.” Sign up for training online or by phone to learn the wisdom of driving and easily pass the exam for the license. A free test drive with an experienced instructor will help you make a decision. Apply for a trial lesson right on the website.
