Engine types

Engine types

Many engine types in the world of automobiles. More now with the growing development of electric cars that are transforming the market. But it is that within the traditional combustion engines, there is already a huge list of engines with very different characteristics: diesel, gasoline, gas and even alcohol. Piston, rotary, four-stroke and two-stroke. The possibilities are almost endless.

Throughout the history of the automotive sector, all kinds of mechanical devices. However, many have fallen by the wayside, leaving us the most efficient, ecological, powerful, or at least the easiest to manufacture or maintain. Without going any further, the latest trends, leaving electrification aside, are that large displacement engines and many cylinders are disappearing and diesel engines are gradually losing prominence.

In this article we are going to review the different ways to classify motors: number of cylinders, their placement, their fuel... Although we are also going to mention the differences that exist within the electric motors and the hybrids. We must not forget that soon, it may be more important to know the difference between a synchronous and an asynchronous electric motor, than the difference between a turbocharged engine and an atmospheric one.

Different types of internal combustion engines

Internal combustion engines

Before starting to talk about combustion engines, which are currently all pistons, you have to make one special mention to rotary engines or Wankel type. These work in a very different way by not having the cylinders and pistons that we are used to. They stopped being manufactured years ago, among other things due to their difficult maintenance. However, everything indicates that they will return shortly from the hand of Mazda, if only in the form of electricity generators.

wankel rotary engine
Related article:
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According to the placement and number of cylinders

Engines with cylinders in line (L)

Engines with cylinders in line

Focusing on conventional piston engines, we could conclude that most of the cars we see on the street every day have inline engine. In this engine, the cylinders are located one after the other and the most common are the well-known 4 cylinders online. In the smallest vehicles we can find only 3 cylinders. Besides, BMW is known for its 6 cylinders in line and other Volvo or Audi models have 5 cylinders in line.

V-cylinder engines

Another fairly widespread type are the so-called V-engines. They are usually motors large displacement, although there are also low displacement models on some motorcycles. These motors are characterized by having the cylinders arranged in a V shape, being able to vary its angle of inclination, which determines different properties to the engine. Usually, the most common are usually the well-known V6, although we can also find V8, V10, V12 and even with odd cylinders, such as V5.

A variety of these engines are VR, such as the VAG group VR6. This type of engine is characterized by having a very closed V, almost resembling a traditional inline engine, even sharing the same butt. Another variety are the W which, to give us an idea, are 2 V-engines together and which can be up to W16, like the Bugatti Chiron.

V-cylinder engines

Both the VR, W and V engines, They are quite balanced and refined, having a very characteristic sound.. They are usually mounted on slightly more exclusive and less common cars, although we can also find them on everyday cars.

In addition to these qualities, V-engines tend to be more compact longitudinally than in-line engines. Placing the cylinders one behind the other takes up more space across the length than arranging them in two rows that form a V. That is One of the reasons for which the 10 most expensive cars in the world they have V or W engines. Space can become a problem when using 8, 12 or even 16 cylinder engines.

In the next video you can see what cars they are and what engines they have:

boxer engines

These are rarest piston engines. There are already few cars with engines of this type and most are from Subaru and Porsche. They have the pistons placed horizontal to the ground, so the pistons go in and out in this curious orientation. Hence his name "boxer".

opposing piston engine

This typology does not really talk about the arrangement of the cylinders. Although it does have an interesting peculiarity: they are motors that have two pistons per cylinder. This way, each explosion what happens inside push two pistons placed at each end of the cylinder. That is why they normally need two crankshafts to transform both longitudinal movements into rotary ones.

opposing piston engine

As an exception to this, there is, for example, the INN engine. A Spanish company that has developed an opposed piston engine that replaces the crankshafts with cam plates. In addition, it has the cylinders placed in a square to save space. Something that could be added to the type of engines according to the cylinder arrangement, although it is very rare.

Types of engines according to the fuel they burn

Gasoline engines

Engines gasoline They are internal combustion engines. That is to say, engines that require a spark to ignite the fuel, Which is generated by a spark plug. Like any combustion engine, its operation is based on the strong expansion of the air-fuel mixture when it is turned on.

Types of motor fuels

Gasoline engines can be four-stroke or two-stroke. The first is the most used in vehicles, by far, leaving the two-stroke for some mopeds and some industrial machines since they have been relegated due to their higher emissions. If you notice, engines of this type emit slightly bluish colored smokeBecause they mix oil with gasoline to lubricate.

It is called four-stroke because it has four phases during its operation: admission, compression, expansion y Escape. For which the crankshaft has given two turns. On the other hand, the two-stroke performs the aspiration and compression in the same upward movement of the piston and the expansion and exhaust in the downward movement. So the crankshaft has only made one turn.

inside of an engine
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Gasoline engine: Bentley W12 6.0-liter TSI

Inside four-stroke engines. There are three main types of cycles: the Otto, Miller and Atkinson. To which could be added the budack combustion cycle presented by Volkswagen in 2017. The first responds to the description we have made of four-strokes and the other two leave the Válvulas open intakes, to return part of the mixture to the admission again during the compression phase. With this they manage to greatly reduce the effort they have to make to compress the mixture, so they are more efficient. The downside is that they get less power. The Miller also adds a volumetric compressor to add pressurized air.

diesel engines

These engines use diesel to work. A fuel that can't be ignited with a spark, as gasoline engines do. Instead they have to ignite the air-diesel mixture by pressure. That's why the compression ratio of these engines is much higher than in gasoline engines.

Diesel TDI

In general, they are more efficient than gasoline, although they require more and better emission reduction systems so as not to pollute too much. In this sense, they emit more NOx molecules than gasoline, in addition to generating more cinder. For this reason, and despite the anti-pollution systems that include the most modern ones, they are being severely penalized by the administrations.

diesel engines They can also be two and four times, and the latter is very similar to the cycle Otto. The main difference with gasoline engines with this cycle, apart from the self-ignition by pressure, is that fuel injection is done in the last moments of the compression phase. In addition, currently all cars with this type of fuel have a turbo.

gas engines

internal combustion engines they can also use gas instead of gasoline. These are usually Natural Compressed Gas (NCG) or Liquefied petroleum gas (GLP). They are more ecological than those that use only gasoline. Especially for generating much less NOx.

Some gas engines have a CNG or LPG quality sensor

Nitrogen Oxide or 'Nitro'

Contrary to what some people think, nitrogen oxide not a more powerful fuel which increases engine power. Actually, they are molecules that break when heated and release more oxygen into the combustion chamber. Therefore, acts as a fuel and not as fuel. That is, by having more oxygen available, can burn more gasoline and therefore generate more energy. It is prohibited in Spain and increasingly in more parts of the world.

This is a form of supercharging, but instead of using a turbo to push air under higher pressure, they introduce a gas that releases oxygen when heated. Engines that are set up to use Nitro need to be modified in a number of ways. They usually require pieces with greater resistance to heat y changes in electronics to adapt its operation when nitrogen oxide is injected. For example, the variation of ignition advance and the increase in the amount of fuel. Remember that it only activates for a few seconds, to then burn gasoline again with the oxygen in the air.

Aspirated engine vs. turbo engine

naturally aspirated engines and turbo engines

La opposed between the engines atmospheric and turbocharged is that, while the former work with ambient pressure air, seconds enter more pressure forced. By having more oxygen, turbocharged engines can burn more fuel in a combustion chamber of the same or even smaller size. This not only allows to reach a power greater if you will, but also allows a better response at low and medium regime. Something that atmospheric engines usually lack and, if they can correct it, they do not reach the capabilities of a turbo engine.

The usual in conventional cars with turbo is to use pressures in the air that blow between 0,7 and 0,9 bar. Some values ​​to which must be added to the atmospheric pressure that the ambient air already has, that is, 1 bar. In this way, the actual pressure inside the combustion chambers will be between 1,7 and 1,9 bars. Although these values ​​may be much higher in high performance cars, reaching for example up to 6 pressure bars.

Related article:
Let's take care of the turbo of our car

The turbo pressure of high performance engines is very high

Lately they are widely used low blow turbos, in which very large increases in power are not sought. Instead of this they try to improve the response at midrange to achieve a more favorable relationship between benefits and consumption. In these cases, the blowing pressure is between 0,2 and 0,5 bar. In these cases, the ultimate goal is to improve the eficiency. As the engine responds better at low revs, it has to rev less to achieve the same as an atmospheric. To which is usually added a reduction in the size of the engine and even eliminate some cylinders.

Despite these virtues of the turbocharged engine, there are brands that are still betting on naturally aspirated engines. That is the case of brands like Toyota with the engines they use in their hybrids, Subaru on some of their engines boxer y Mazda with its engines with an especially high compression ratio. To the latter we must add the motors Skyactiv-X that this Japanese brand has recently developed. Thanks to its ignition system similar to diesel and other technical innovations, it promises a relationship between consumption and performance similar to diesel.

Types of electric motors

Electric motors like the one in this Hyundai Ionic

fiscal horses
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Electric mobility is experiencing very rapid growth globally. The evolution of batteries and electric motors it is allowing little by little to become reasonable options for many people. Therefore, it would not be surprising if over time it became more important to know about electric motors than combustion engines. At least at a high user level to know how to buy wisely.

electric motors they are much simpler than the combustion engines of a lifetime. Its basic parts are a stator and a rotor.. Elements that always have, whatever the type they belong to. Furthermore, since they are more compact and that already generate a rotary movement (so they do not need crankshaft), save much of the transmission system of a conventional car with internal combustion engine.

Electric motors have many virtues, like this Tesla's

They are often credited with pushing hard from 0 rpm. That is, from the first moment we stepped on the accelerator. In addition, they are also said to be able to push hard up to a very high rev range, so they don't have to have gears. However, this is not always the case as there are several types of electric motors with different characteristics. They can be divided into three categories:

  • permanent magnet synchronous
  • Switched Reluctance Synchronous
  • asynchronous or induction

If you want to know more about them, we recommend that you read the following article where we detail each one:

How does an electric car work?
Related article:
How an electric car or EV works

Hybrid powertrains

Hybrid powertrains like the one in the Toyota Prius

As you can see, this section is not called hybrid engines. We use the term powertrain because hybrid engines as such do not really exist. There are the combinations of combustion and electric engines, which give rise to hybrid powertrains.

What you need to know in this type of mobility is that the combustion engines that are usually used are specially adapted to this use. For example, the engines most used in current hybrids are those of Atkinson cycle for being more efficient. The extra power that the electric motor gives when necessary, compensates for its lower performance.

The ways to combine combustion and electric engines they are very numerous. They can be ordered separately for each axle, you can put an electric motor in the transmission, and even use several electric motors in different places. If you want to know more about this type of mobility, we recommend the following article:

How does a hybrid electric car work?
Related article:
How does a hybrid electric car or HEV work?

Images: James Harland, Jan Beckendorf, The NRMA, Urduñako udala, feschesheli


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      Angelo Suarez Rodriguez said

    This has very good information to know what internal combustion engines are like, thanks to this page I can finish my project on engines