As soon as the first internal combustion engine was created, work began almost immediately to improve it. As the main task, the developers have identified for themselves such as reducing the overall dimensions of the motor itself, increasing its power and increasing the stability of the car. Thus, the first boxer engine appeared, which solved a sufficient number of problems, but not all.
Initially, the civil automotive industry did not accept the boxer type of motor, and it was installed exclusively on military equipment. The first civilian car, where a new type of engine was installed, was the Beetle from the Volkswagen concern. Over time, when more than 20 million of these cars were produced, the idea of using an opposition engine was adopted by brands such as Porsche and Subaru.
Opposition engine - design differences
Despite the fact that the scheme of the boxer engine, in principle, is one, there can be two options for its execution. This is due to the fact that the same technical solution, namely the horizontal arrangement of the cylinders, is implemented in different ways.
Boxer engine
Such a motor is designed in such a way that the pistons are constantly located at a certain distance from each other - when one is at the maximum distance from the engine, then its “neighbor” occupies exactly the same position. This type of boxer engine got its name because of the similarity of piston movements with the movements of a boxer. It is this motor that the Subaru concern very widely uses in its cars.
Motor "OROS"
Such an engine is arranged somewhat differently. Its revival has begun quite recently, helped in no small measure by the investments of Bill Gates.
This is a standard two-stroke boxer engine, in each cylinder of which there are two pistons that move towards each other. All pistons are mounted on the same shaft. One of them is designed to let the combustible mixture into the combustion chamber, the second - to remove exhaust gases. This arrangement allowed the designers to abandon the drive mechanism for the valves, as well as the cylinder head itself. It is worth noting such an advantage as the operation of all pistons with one crankshaft.
Are there any advantages to a boxer engine
Like any other type, a boxer engine has advantages and disadvantages, which are due to design features. Despite some negative sides, the advantages of this type of motors are very numerous.
There are disadvantages too
What does a boxer engine mean in terms of its merits is clear to many, but nevertheless there are a number of disadvantages due to which such a motor is not yet installed on all cars produced today.
Some features of modern opponents
Since its development and installation of the first boxer engine on a Volkswagen in 1938, this type of engine has undergone major modernization. Four-cylinder engines are currently the most widely used - they are the most environmentally friendly, compact and economical in terms of fuel consumption. In many ways, this was the result of many years of painstaking work of engineers who embodied a sufficient number of unique developments in such motors:
The high reliability and power of the boxer engine is also evidenced by the fact that this particular type of engine was installed on the Soviet T-64 tank, and later on the T-72. Only such a boxer engine, the principle of which has changed little since then, was able to provide high power with its relatively small overall dimensions. For reference, only he could give out about seven hundred horsepower at 2 thousand revolutions and a volume of 13.6 liters. You can learn a lot of interesting facts about the work of opposition motors by watching the video:
How to Avoid Costly Boxer Engine Repairs
Any boxer engine has pros and cons, which is quite natural. To avoid problems, the elimination of which may require very serious material costs, it makes sense to heed the advice of specialists and operate the car with a boxer engine installed correctly. The first thing you should pay close attention to is the exact observance of the terms of maintenance, which should be carried out at specialized stations and only by qualified personnel.
Great care should be taken when choosing engine oil. Preference should be given only to well-known brands, the purchase should be made either in specialized stores with an impeccable reputation, or in branded service centers. Using a low-quality product can cause a lot of trouble for an overly economical driver. The same can be said about the quality of fuel. Fuel containing a large amount of "unauthorized" additives seriously reduces the life of the engine, leading to the need for costly repairs.
Many car owners who purchase vehicles with a boxer engine have heard about a high-quality and efficient cooling system, so they don’t really get hung up on this moment. You should not drive the engine mercilessly, especially in the warm season - the most advanced cooling system may not be able to cope with its task. To a large extent, it contributes to difficult cooling and the absence of periodic washing of the engine - the accumulated dirt on the motor significantly complicates heat transfer, contributing to excessive heating.
Despite some difficulties, the boxer engine proved to be excellent, significantly increasing driving comfort and safety. It should be noted that the prevailing opinion about the extreme high cost of owning a car with such an engine is clearly exaggerated. For example, consider the Subaru brand, which has long produced cars with this type of engine - they have never been among the cars with excessively expensive maintenance, and many cars with standard engines cost their owners much more. Significant savings on fuel also affect here, which is much less required - depending on the specific car model, fuel savings can reach up to 50%.
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. From 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 frontal 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 engine with high revs, which makes it possible to create sports-type models on this base.
Another feature is the characteristic sound during operation of the 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 repair;
increased consumption of 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 by the Japanese company 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.
They differ from each other not only in the type of fuel consumed, but also in design features. For example, there is a great variety in the arrangement of cylinders. Each option has its strengths and weaknesses. In this case, the pros and cons of a boxer engine will be considered.
Read in this article
What are the features of a boxer engine
In piston internal combustion engines (and there are also rotary ones), the placement of cylinders can be different in relation to each other: at an acute angle, in one row, star-shaped, and so on. In the case of a boxer, the cylinders are in the same plane and placed one opposite the other at an angle of 180 degrees. Unlike many in-line engines, the boxer unit often has two, as well as a vertical distribution. There are several types of boxer engines. Among them, the most famous are:
- Boxer ("Boxer"). It differs in that the pistons located in front of each other move like boxers in the ring. That is, when one of them is at the highest point, the second occupies the lowest position. They are all the time equally removed from each other;
- OROS - Opposed Piston Opposed Cylinder. The principle of operation in this case is that the pistons are in pairs in one cylinder (upper and lower piston). They move towards each other, rotating the crankshaft.
- 5 TDF. This is a Soviet-made two-stroke tank engine, which was used on the T-64 and T-72 tanks. An interesting feature of this unit is its multi-fuel. The main fuel for him is diesel fuel. However, with the help of a special switch on the high-pressure fuel pump, it was possible to start the operation mode on gasoline or on a mixture of gasoline with kerosene and diesel fuel, and the engine could also run on jet fuel. True, it was also necessary to correct the ignition angle (injection timing).
Many companies were actively involved in the development of power units. For example, Volkswagen has paid attention to this type of units since the mid-30s of the last century. These were not just experiments, but the desire to develop their own boxer motor, reduce the level of vibrations that occur during the operation of a traditional V-shaped or in-line engine, etc. By the way, Volkswagen engineers also applied their development in the legendary Volkswagen Beetle. And since the 60s, boxer engines have been actively used by the Japanese company Subaru, which was engaged in development in parallel with the Germans.
Advantages of the boxer ICE
By and large, the operation of a boxer engine does not differ from the principle of operation of units of other designs. However, such an arrangement of cylinders has certain advantages, as well as disadvantages.
- The most noticeable advantage of the power plants under consideration is the almost complete absence of vibration during operation. This effect is achieved due to the arrangement, which balance each other. This not only adds comfort, but also significantly increases the service life. This is where the second "plus" comes from;
- Impressive boxer engine life. There is evidence that quite often the mileage before the first overhaul was at least 500 thousand kilometers. Of course, the driving style makes its own significant adjustments. And, nevertheless, the overhaul period is quite long. However, quite often one can meet the statements of specialists and motorists that 800-900 thousand before the first is nothing more than a beautiful fairy tale;
- The motors of the design considered in this article provide vehicles with a low center of gravity. This quality is especially appreciated in powerful sports cars. After all, passing turns at high speeds, it is very important to maintain stability;
- Also, one cannot fail to mention the space saving under the hood. Although this point will seem controversial to many, because winning in height, you need to make the hood wider or longer.
Here, perhaps, are all the essential advantages of the opponents. Now we need to consider the disadvantages, which, unfortunately, are somewhat larger.
The main differences, as well as the advantages and disadvantages of 8-valve engines compared to 16-valve engines. Which power unit is better to choose.
boxer engine- a special type of power plant, reminiscent of a traditional internal combustion engine, 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 of the Volkswagen automobile company. Then the unit was a 4-cylinder boxer, the volume of which was 2 liters. The maximum power of the power plant reached 150 horsepower.
The boxer motor has become very widespread. Today, such eminent automobile concerns as Subaru and Porsche are engaged in the production and installation of the unit. 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 OPOS boxer engine are that the pistons function in favor of a single 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 of the 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 repairs, 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 maintenance, which may affect the choice of most motorists not in favor of the presented units. However, large manufacturers (Porsche, Subaru) believe that quality requires a large investment in 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 repairs are carried out 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.
Modern reciprocating internal combustion engines (ICE) can be classified based on criteria such as the type of fuel consumed 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 ones, they are more “flat” and take up less space in the 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 the main feature of 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. Combustion chambers in 5 TDF boxer engines are located between the pistons, they operate on both gasoline and 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 this precisely 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 such motors implies high manufacturing accuracy 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 costs a lot 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 models of Volkswagen 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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