boxer engine - special type power plant resembling a traditional engine internal combustion, in which the cylinders have a special arrangement - horizontal. In the people, such units are known as "boxers". The motor received such a nickname due to the fact that the pistons move either away from each other or towards each other. In this case, the pair of pistons is in one position, for example, from below.
The very first sample appeared in 1938 thanks to the efforts car company Volkswagen. Then the unit was a 4-cylinder boxer, the volume of which was 2 liters. The maximum power of the power plant reached 150 Horse power.
The boxer motor has become very widespread. Today, the production and installation of the unit are carried out by such eminent automobile concerns like Subaru and Porsche. Previously, it was possible to find the engine on models from Toyota, Volkswagen, Honda, Ferrari. Similar installations are used in motorcycles, Ikarus buses and some military equipment (for example, tanks).
The principle of operation of the boxer engine and its device
To fully understand what a boxer engine is, you need to familiarize yourself with its structure. As noted above, this is an internal combustion engine, which has a special structure - a pair of pistons moves in a horizontal plane (not up and down, but from left to right). The second, adjacent, is in the same position.
The number of such cylinders varies from 2 to 12 (their number is always a multiple of two). The most common samples have 4 and 6 cylinders. For sports cars, 8- and 12-cylinder engines were developed. Professionals note that the principle of operation of 2- and 4-cylinder boxers is no different from traditional engines. Those that have six cylinders have their own characteristics.
Types of boxer engines
The principle of operation of a boxer engine also varies depending on the features of its device. Even such a simple unit can have several variations in the operation of the pistons. Therefore, the following types of motors are distinguished:
- boxer boxer often used in the production of Subaru vehicles. How does a boxer engine of the claimed type work: the pistons are located at a predetermined distance opposite each other, for example, if the first is fixed at a certain distance from the axis of the engine, then the second will take a similar position. Moreover, they are located each in a separate cylinder. The described principle of functioning resembles a boxing match, hence the name of the type.
- OROS has a completely different principle of construction and the order of operation of the pistons. Such devices are two-stroke. One cylinder has two pistons at once, which are attached to one crankshaft. The first is responsible for the intake of the mixture, the other for the timely exit of combustion products. This design does not have a head, which is often found on the cylinder block. The advantages of the OROS boxer engine are that the pistons function in favor of one crankshaft. This type of device has a small mass and is smaller in size. Consequently, the scope of application has significantly expanded. In addition, this engine can run on different fuels - diesel or gasoline. Finally, here are the main benefits:
- pistons travel a much shorter distance, as a result of which the friction force is significantly reduced, which negatively affects wear resistance;
- efficiency increases, because harmful gases do not affect the combustion chamber, but put pressure on the pistons;
- the motor is 30-50% lighter than usual;
- the boxer engine has fewer parts (50% on average);
- profitability;
- lack of a valve drive system.
- the motor takes up much less space under the hood.
- tank engine (5TDF, designed specifically for the T-64 and T-72). The resource of the boxer engine is designed for military equipment of large dimensions. Here the pistons share one cylinder and move in the same direction, but each has its own separate crankshaft. The place where the fuel ignites (combustion chamber) occurs when the gap between the pistons becomes minimal. As with OROS engines, air is admitted into the cylinders, and unnecessary gases are removed by turbocharging. The counter stroke of the pistons made it possible to design a compact but powerful unit. The power plant has a maximum number of revolutions of 2000, and a power of 700 horsepower. The volume, respectively, reached 6 and 13 liters.
Benefits of a boxer engine
Each element in the automotive body has its own advantages and disadvantages. The advantages of a boxer engine are as follows:
- lowering the center of gravity vehicle, which positively affects its stability;
- the resource of the motor will certainly increase (if operated correctly, it reaches about 1 million km);
- due to the special interaction of the pistons, the level of vibration and noise reduction is reduced.
Cons of a boxer engine
If the boxer engine has advantages, then there are certainly certain disadvantages:
- costly self-service - requires the involvement of professionals;
- expensive and complex repair, because the components are distinguished by their increased cost;
- the high cost of the power plant;
- design complexity;
- increased oil consumption during operation.
Despite the disadvantages described above, many automakers equip their models with just such units. Development companies carefully weigh all the pros and cons before using just this type of motor. The main plus is great opportunities and broad prospects.
So, all the negative aspects, in fact, come down to expensive service, which may affect the choice of most motorists not in favor of the presented units. However, large manufacturers (Porsche, Subaru) believe that quality requires big investments to the service.
For example, a Japanese automaker is not going to return to traditional internal combustion engines, because they believe that in this case they will take a technological step back. Since car models have proven themselves only in the best way, the level of sales does not depend on the prices for service.
Difficulties in the repair and maintenance of a boxer engine
It is important to note that often the positive aspects of these engines are noticeable only in power units that have six cylinders, but 2- and 4-cylinder ones are not much different from traditional internal combustion engines.
If you need to carry out some manipulations with this type of engine, then you definitely need to contact the specialists in a car service. You can only change the oil yourself. It is better to entrust even the replacement of candles to professionals, beginners can easily damage the cylinder head. Complete renovation produced only at special service stations.
Timely and systematic decarbonization can extend the service life. This procedure involves cleaning the surface of the combustion chamber, valves and pistons from carbon deposits. The operation is carried out in the autumn season or in March, when it is also very reasonable to check the engine oil.
In the material, we examined what the concept of "boxer engine" means, described the principle of operation, possible pros and cons. We hope that this will help determine the choice of not only the motor, but also the future car model on which a similar power unit can be installed.
I continue to talk about internal combustion engines. Moreover, I like to talk about incomprehensible engines for a simple layman, for example, from Volkswagen. Today, no less interesting engine, which is also installed on a narrow range of cars. We are talking about a boxer engine. Mostly now such units are used Subaru, as well as the Volkswagen Group Corporation, in their vehicles. So what kind of engine is this? Read more…
- an internal combustion engine in which the pistons are horizontal (or at an angle of 180 degrees), as opposed to an in-line internal combustion engine, in which the pistons are vertical. That is, in simple words - it can be called a horizontal engine. The pistons of such a unit are located - two on the right and two on the left. During operation, the pistons converge and diverge in a horizontal plane. Since the pistons are separated, each group of pistons has (two on the right and two on the left), two camshafts. That is, on the right there are two camshafts - 8 valves and the same on the left. The gas distribution mechanisms in the boxer engine (camshafts and valves) are located vertically, in contrast to the in-line classic engine, where they are located horizontally. Here is a small diagram.
The first boxer engines appeared back in 1938, they were installed on Volkswagen Käfer cars (in chic use of the Volkswagen Beetle). Exactly Volkswagen pioneered the horizontally opposed engine. Some modern cars, which are part of the Volkswagen Group, are now equipped with such engines (for example, the Porsche 997, Porsche Boxster etc.). Also in the 40s of the last year, SUBARU conducted its independent development of its engine. And to this day, Subaru completes its cars exactly horizontally - with boxer engines.
Why was the boxer engine created?
It was created to lower the center of gravity of the car. Probably everyone knows that the lower the center of gravity, the better the driving characteristics of the car, while cornering, the car rolls will be less.
Benefits of a boxer engine
1) As I wrote above, it was created to lower the center of gravity of the car, which has a very good effect on driving performance.
2) Another plus is the location of the cylinders. When moving towards each other in a horizontal plane, extraneous vibrations are much more strongly damped. Therefore, this engine is considered much quieter than its in-line or V-shaped counterparts.
3) Also of the pluses, I would like to note the large resource of this type of engine. For example, SUBARU engines have a resource of about 1,000,000 kilometers, with proper use and timely replacement of consumables.
Cons of a boxer engine
1) The first and most significant disadvantage is the complex repair of such an engine.
2) A complex structure, which means the expensive price of this engine.
3) Difficult maintenance.
This unit is strong, but complex in structure. His dynamic characteristics similar to inline gasoline engine. Power and consumption. And now a short video.
SUBARU boxer engine video
Let me finish with this, I think it has become a little clear what it is and how it works.
A power unit such as a boxer engine (in particular, manufacturer Subaru) is similar in principle to a standard, in-line internal combustion engine. What distinguishes it is the specificity of the location of the pistons, cylinders, due to the horizontal (and not the usual vertical) installation of the engine. Therefore, the pistons of the boxer engine are located horizontally, moreover, opposite (opposite) to each other, in pairs. Also, each of these pairs of engine pistons has a pair of camshafts.
At first glance, Subaru's boxer engine is more compact than others of the same power and volume. This illusion is created because it is “flat”, evenly fills engine compartment. At the same time, the motor-plate is short, flat, but wide. Its design is represented by semi-blocks of two cylinders, but in width, in addition to the crankcase with a pallet, like an in-line one, there is also a semi-block and a head.
The first Subaru boxer internal combustion engines were noticed and installed on sports cars by racers. Under them, later developed and 12 cylinder engines, instead of the used 6-cylinder ones. 
Benefits of a Subaru boxer engine
Subaru's boxer engine has many advantages:
- Mass distribution is symmetrical about the axle, not specifically on it (less load on rear wheels) - due to the low center of gravity (plus the possibility of its displacement).
- High functionality, a relatively long duration of work until the first need for repair is the most important plus and argument for installing a Subaru boxer engine.
- The minimization (or total absence of vibration) that, when installed conventional engine creates considerable discomfort for the driver/passenger.
The first plus (dignity) is most appreciated by the owners of sports cars. Because, at high-speed turns, the Subaru boxer engine will give more sustainability. In addition, the speed indicators for cars using these particular engines are relatively better than similar ones (especially among 12-cylinder ones).
The second advantage is engine longevity– has been extensively checked/confirmed. Until needed overhaul the boxer engine will please the car owner with more than one thousand trouble-free kilometers traveled.
The last (third advantage) is possible, among other things, due to the horizontal arrangement of the pistons working against each other, creating a certain balance, counterweight. Not all models of Subaru boxer engines, unfortunately, can boast maximum vibration resistance. The best way to "resist" vibration loads is a six-cylinder boxer engine (similar to a 6-cylinder variation of an in-line engine). But already the 4-cylinder does not have such successes and significant advantages. 
Subaru boxer engine cons
However, in every advantage of Subaru's boxer engine, you can find a small fly in the ointment. Of these shortcomings:
- The high cost of engine maintenance, the difficulty in selecting the necessary spare parts. And, among other things, it is advisable to trust only professionals who specialize in this in matters of repair of these particular engines.
- The high cost of Subaru's own boxer engine, explained by the complexity of the design.
- Also, to consumable items using such an engine, high flow oils.
Self-repair of a boxer engine is also impossible due to the need for a specialized tool, without which many parts of a non-standard, horizontally located engine cannot be reached.
The spectrum of use of the Subaru boxer engine
The slightly difficult financial situation of a significant number of motorists does not allow the popularity of boxer cars to spread. Subaru engines. Their application is most widely used in the field of racing, high-speed car models. Because here, the previously mentioned advantages of Subaru boxer engines are much more important and cover the disadvantages of their use.
In addition, they are installed, of course, in Subaru car models. Also, Porsche often resorts to installing these particular engines in their cars.
An engine is called a boxer engine, the cylinders of which are located in a horizontal order relative to each other. A similar structure scheme has a name: a V-shaped engine with a 180-degree camber angle. With in English the word "opposite" is translated - "located opposite". Consider the boxer engine - the pros and cons.
Features of the boxer motor
Despite the similarity with the V-engine, the boxer has nothing to do with it. The difference is that in the boxer, two adjacent pistons are located in the same plane relative to each other. In a V-shaped engine, the pistons, when moving at certain moments, occupy the position of the upper and lower "dead center". In the opposition, they simultaneously reach either the upper "dead center" or the lower one. This improvement of the V-shaped motor resulted from the location of the cylinders at a developed angle.
Another innovation was the location of gas distribution mechanisms in a vertical plane. All this freed the design of power units from imbalance and increased vibrations, and made driving a car as comfortable as possible. Now the vibrations from the engine are not transmitted to the body and do not shake the car.
Boxer engines always have an even number of cylinders. The most common are four- and six-cylinder engines.
The design features of the boxer-type power unit have significant advantages over other types of motors:
The center of gravity is shifted down;
economical fuel consumption;
low vibration level;
increased motor resource;
passive safety in a head-on collision.
The center of gravity shifted down allows for better stability of the car and optimal handling during active maneuvers and 
sharp turns. During sharp turns, roll is significantly reduced. The location of the engine on the same axis with the transmission provides better power transfer. The absence of balance shafts saves fuel consumption.
The engine runs smoothly. A low level of motor vibration is achieved due to the coordinated rotation of adjacent pistons. The location of the crankshaft on three bearings, instead of the usual five, is another advantage of the boxer engine. This significantly reduces the mass of the engine and its length.
The location of the pistons in a horizontal plane gives the system greater rigidity, which significantly reduces mechanical losses during the operation of the power unit.
Passive safety is ensured by the fact that in the event of a collision, the motor easily goes down under the car. As a result, there is a decrease in the intensity of the impact directed at the passenger compartment.
The increased diameter of the cylinders provides the motor high revs, which makes it possible to create sports-type models on this base.
Another feature is characteristic sound when operating a boxer power unit: it is more pleasant to hear.
Disadvantages of a boxer engine.
The advantages of the boxer engine are obvious. The disadvantages are:
Labor-intensive repairs;
increased consumption engine oil.
To repair the engine, it is completely removed. However, this is not the problem. Replacement parts are very expensive, and assembling the engine causes a lot of headaches. If, when repairing an in-line motor, the driver can independently replace the candles, then this is impossible in the boxer. Any repairs must be carried out on special equipment, which is available only at the service station.
The history of the opposition
Initially, this type of power unit was used in the military industry, in particular, on domestic tanks. In the future, Ikarus and the Dnepr MT motorcycle drove on similar engines. At present, two firms are engaged in the installation of a boxer on their products - Porsche and Subaru.
The first developments appeared in the thirties of the last century, when Volkswagen engineers began to improve the V-shaped and in-line engine. In the sixties, the idea was intercepted Japanese firm Subaru. In 2008, Subaru releases the first diesel-powered boxer. Distinctive features - a four-cylinder engine with a capacity of 2 liters. Power indicator - 150 l / s.
Video principle of the Subaru boxer engine
Despite the high cost of spare parts and maintenance in service stations, the pleasure of driving a car equipped with a “boxer” cannot be compared with anything. High stability, easy handling, car responsiveness to all driver actions speak for themselves.
Modern piston engines Internal combustion engines (ICE) can be classified based on criteria such as the type of fuel used and the arrangement of the cylinders. If with the division of engines based on the type of fuel, everything is more or less clear even to people who are very far from technology, then with the division according to the arrangement of cylinders, everything is not so obvious. In this material, we will consider one of the types of internal combustion engines with an unusual arrangement of cylinders, namely a boxer engine. Here you will learn about what a boxer engine is, how it works, what its pros and cons are and where it is used.
The design and features of the boxer engine
Scheme of operation of a boxer engine
Opposed internal combustion engines are those whose cylinder camber angle is 180 °. The pistons in them move in a horizontal plane, and mirror each other. This means that they reach their highest point at the same time. By the way, this is precisely one of the main differences between boxer power units and the more common V-shaped ones: in them, the movement of the pistons is carried out synchronously (when one of them is at the top point, the second is located at the bottom).
Due to this arrangement of cylinders, boxer engines have a low center of gravity. In addition, their height is significantly less than that of the V-shaped, they are more "flat" and take up less space in engine compartment. One of the distinguishing features of boxer engines is the presence of two gas distribution mechanisms (they, like the V-shaped ones, most often have one crankshaft). As for the principle of operation of these motors, it is exactly the same as that of all other internal combustion engines: the movement of the pistons that drive the crankshaft is carried out due to the pressure of the gases formed during the combustion of the fuel mixture.
Types of boxer engines
To date, there are three main types of boxer engines:
- boxer;
- OPOC;
- 5 TDF.
They differ from each other mainly in the way in which the pistons move in them.
boxer. In boxer engines of this type, each piston is located in its own cylinder, and they are located at a certain distance from each other, which always remains constant. This is precisely what main feature such power units. Since in the process of functioning the movement of their pistons resembles the movements of boxers in the ring, they received the name Boxer.
OPOC. This abbreviation stands for Opposed Piston Opposed Cylinder, and the design feature of boxer engines of this type is that they have two pistons in each of the cylinders. They move towards each other. OPOC boxer engines are 2-stroke and do not have cylinder heads or valve trains. Thanks to this design, these power units are lightweight, and they are both gasoline and diesel.
5 TDF. This type of boxer engine is a domestic development. At one time it was created specifically for installation on T-64 tanks, a little later it was used in the T-72. Just like in the OPOC boxer engine, its cylinders contain two pistons that move towards each other, but unlike it, each of them has its own crankshaft. The combustion chambers in 5 TDF boxer engines are located between the pistons, they work both on gasoline and on diesel fuel. Now these power units are no longer produced.
Pros and cons of boxer engines
Crankshaft and pistons of a boxer engine
Like other types of internal combustion engines, boxer powertrains have both pros and cons. As for the advantages, one of the most significant of them is a very low level of vibration during operation. These motors owe it to the opposite arrangement of their pistons. The fact is that when moving, they mutually balance each other, and the imbalance of forces that leads to vibrations is almost completely absent.
This advantage of boxer engines entails another significant plus: since there are practically no vibrations, the wear of moving parts is much slower than in, say, V-engines. Accordingly, the resource of such motors is very large: practice shows that their mileage before overhaul is about half a million kilometers. Some owners of cars with boxer engines claim that this figure is even higher in practice, ranging from 600,000 to 700,000 kilometers.
Another plus of this type of power units is the low center of gravity. That is why they are often installed on sports cars. When cornering at high speeds, boxer engines provide increased stability of the machines. In addition, as mentioned above, the advantage of motors of this type can be considered their small height. In fairness, it should be noted that at the same time they are somewhat wider than power units of other types (for example, the same V-shaped motors).
As for the disadvantages of boxer engines, the main ones are the following: high cost and difficulty in repair. The design of these motors high precision manufacturing of many of their main elements, the use of expensive high-strength materials. In addition, their assembly and adjustment is much more complicated than similar procedures for V-shaped or in-line internal combustion engines. Diagnosis and troubleshooting of boxer engines is possible only with specialized equipment and specially trained personnel. It goes without saying that even a minor repair of such motors is expensive for the owners of the cars on which they are installed.
Also, a significant disadvantage of boxer engines is a significant oil consumption. However, in terms of such an indicator as fuel consumption, they are still inferior to modern V-shaped and in-line power units.
Scope of boxer engines
Boxer engines are not as widely used as V-twins and in-line engines, but there is an automaker that has been installing this type of engine in its cars for half a century. This is the famous Japanese company Subaru. In addition, boxer units can be found on some Volkswagen models and Porsche, they were once equipped with Soviet motorcycles "Ural" and "Dnepr", Hungarian buses "Ikarus".
It should be noted that in recent years, interest in power units of this type has increased significantly. According to some reports, research and development to improve the OPOC boxer engines, conducted by a group of American engineers, is funded by Bill Gates.
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