Others will tell you what you have to do, if you are interested in a Diesel or a petrol engine. We are not going to tell you that… we are going to tell you how each one works, what the advantages and disadvantages of each one are so that you can form your own opinion and make your own decisions. Because, more or less since the appearance of the TDi, to put a date, Diesel engines began to improve and there was a real revolution in diesel mechanics, while petrol engines did not evolve as much… something that changed when emissions began to be a priority. I will give you a preview: Diesel engines are increasingly similar to petrol engines, while petrol engines are increasingly similar to Diesel engines… I will explain all this to you in the video in a clear and simple way. Don’t worry. Both types of engines are four-stroke and I think we all know this already, but it is worth doing a brief review of what a four-stroke engine is like and start to see the differences. First stroke. Admission. The piston goes down, the intake valve or valves are open and the engine sucks in either air or a mixture… Atmospheric pressure is an ally that “pushes”, in quotation marks, the air… and if there is a turbo or a compressor in between, even better, we will introduce more volume. Second stroke: Compression. All the valves are closed, the piston goes up and compresses whatever is inside the cylinder. The compression ratio is the ratio between the volume with the cylinder at the bottom and the cylinder at the top, which is called BDC and TDC. A compression of 10 to 1 means that with the piston at the top, whatever occupied a volume of 10, occupies a volume of 1. Third stroke: Explosion or combustion. This is the only working stroke. The valves are closed and the gases are highly compressed. During this stroke, the differences between Diesel and gasoline are very important, so much so that it gives the engine its name. In a gasoline engine, the mixture, which is highly compressed, is ignited by the spark from the spark plug and explodes… that is why they are called internal combustion engines. In direct injection diesels, the fuel is atomized at very high pressure inside the combustion chamber with highly compressed air at a high temperature… As the fuel is injected, it immediately ignites… It does not all explode at once… Fourth stage: Exhaust. This is the same in both cases: The exhaust valve or valves open, the piston rises and expels all the burnt gases that go out into the atmosphere. Everything happens so quickly that the inertia of the gases can be used. Since you know how each type of engine works, in this video we are going to see what advantages and disadvantages these different ways of working bring from a technical point of view… at the end we will talk about legal and tax issues, which also count a lot, but the conclusions are clear: Gasoline is the best option for hybrid, simple, economical, sporty cars and if we do not do many kilometers a year. Diesel is better for large, heavy cars, off-road vehicles, minivans, medium or large SUVs and if we do a lot of miles. Car of the day: It's the Innocenti Minitre, a car with the chassis of a Mini, an Innocenti body and a Daihatsu engine - what a mix! There were many versions with three-cylinder engines, even a Diesel. But the jewel in the crown was a model with a very long name: the Innocenti Minitre 1.0 Turbo De Tomaso from 1986. A beautiful little car, with a three-cylinder engine, one litre displacement, turbo and 72 hp.