Boxer engine- a special type of power plant, reminiscent of a traditional internal combustion engine, in which the cylinders have a special arrangement - horizontal. Such units are popularly known as "boxers". The motor received such a nickname due to the fact that the pistons move either from each other or towards each other. In this case, the pair of pistons is in one position, for example, from the bottom.

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 is 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 structure

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 with a special structure - a pair of pistons moves in a horizontal plane (not up and down, but from left to right). The second, adjacent one, 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 designs have 4 and 6 cylinders. For sports cars, 8- and 12-cylinder engines have been developed. Professionals note that the principle of operation of 2 and 4-cylinder boxers is no different from traditional engines. Those with 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 design. Even such a simple unit can have several variations in the operation of the pistons. Therefore, the following types of motors are distinguished:

1. Boxer boxer often used in the production of Subaru cars. How does the 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 engine axis, 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.
2. OROC has a completely different principle of construction and the order of operation of the pistons. Such devices are push-pull. 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 release 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 is lightweight and smaller. Consequently, the scope of application has expanded significantly. In addition, the specified engine can operate on different fuels - diesel or gasoline. Finally, we will point out the main advantages:
   • the pistons travel a much shorter distance, as a result of which the friction force is significantly reduced, which negatively affects the wear resistance;
   • efficiency increases, because harmful gases do not affect the combustion chamber, but put pressure on the pistons;
   • 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.
   However, it should be remembered that the EPOC is under development, so many unforeseen problems may arise during operation.
3. Tank engine(5TDF, designed specifically for the T-64 and T-72). The resource of the boxer engine is designed for large military equipment. Here, the pistons split 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 OROC engines, air is admitted into the cylinders, and unnecessary gases are removed by means of 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 capacity of 700 horsepower. The volume, respectively, reached 6 and 13 liters.

Advantages 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 has a positive effect on its stability;
• the resource of the motor will certainly increase (if properly operated, it reaches about 1 million km);
• due to the special interaction of the pistons, the level of vibration and noise emission 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;
• high cost of the power plant;
• the complexity of the design;
• 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 this particular type of motor. The main advantage is great opportunities and broad prospects.

So, all negative aspects, in fact, boil down to expensive maintenance, which can affect the choice of most motorists not in favor of the units presented. However, major manufacturers (Porsche, Subaru) believe that quality requires a large investment in service.

For example, the Japanese carmaker is not going to return to traditional internal combustion engines, because they believe that in this case they will take a step back in terms of technology. Since car models have proven themselves only in the best possible way, the level of sales does not depend in any way on service rates.

Difficulties in the repair and maintenance of a boxer engine

It is important to note that often the positive aspects of these motors are noticeable only in power units that have six cylinders, but 2 and 4-cylinder ones differ little from traditional internal combustion engines.

If it is necessary to carry out some manipulations with this type of engine, then you definitely need to contact the specialists at the car service. You can only change the oil on your own. It is even better to entrust the replacement of spark plugs to professionals; beginners will easily harm the cylinder head. Full repairs are carried out only at special service stations.

Timely and systematic decoking 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 "opposed 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.

After the creation of the first ICE, questions arose almost immediately about its improvement and increase in power. The first engine was single-cylinder, and the simplest solution immediately suggested itself, allowing to increase its power - to increase the number of cylinders. But the next steps in the development of the internal combustion engine were not so obvious, since these several cylinders can be arranged in different ways - vertically in a row one after another, at an angle or horizontally. This last version was called the boxer engine, i.e. an engine, the cylinders of which are located horizontally, opposite (opposite) each other.

Boxer engine options

However, even such a simple technical solution - placing the engine cylinders horizontally opposite each other - can be implemented in several ways. When such a boxer engine is running, its pistons can move in different ways.

Boxer boxer

During the operation of such a motor, the pistons are always at a distance from each other, and each works in its own cylinder - if one is located at the maximum distance from the engine axis, then the other, adjacent, occupies a similar position.

This way of working resembles the movement of a boxer, which is why it is called "boxer". Very often uses similar boxer engines Subaru. The described engine is shown in the photo below.

OPOC, reviving old ideas

Another construction principle implements an opposed engine of the OPOC type. Today they are beginning to develop again thanks to the investments of the notorious Bill Gates. The device of such a motor is shown in the figure below.


This boxer engine is a two-stroke engine. The figure clearly shows that there are two pistons in the cylinder, and they are fixed on one crankshaft (in the figure they are designated as red and blue). Red provides an inlet for the mixture, and blue provides an outlet for combustion products. From the design of such a boxer engine, the cylinder head and valve drive mechanism disappeared. In addition, the advantage of such a boxer is that the pistons work on one crankshaft.

All this significantly reduced the weight of the boxer engine and significantly expanded the scope of its use. Another feature is that it can be either diesel or gasoline. It is imperative to clarify that, like any two-stroke engine, it needs to be purged from the cylinders. For this, an electric motor powered from an external source is used. When the boxer engine is on mode, the electric motor is shut off and the air supply is converted to a turbocharger.

Considering the design of such a boxer engine, it is necessary to note its advantages: an increase in efficiency, provided by the fact that the expanding gases press on two pistons, and not on the wall of the combustion chamber, as well as an increased force on the shaft. In addition, each piston travels a shorter distance, which reduces frictional force and therefore losses.

Considering the other advantages that a similar boxer engine promises, it is worth noting - the manufacturer reports that when it is used as a diesel engine, then:

• such an engine is fifty to thirty percent lighter than a conventional turbodiesel;
• such a power unit contains fifty percent fewer parts than a conventional diesel engine;
• takes fifty to forty five percent less space under the hood;
• more economical by fifty to forty five percent.

However, it should be borne in mind that such an opposed power unit is still quite crude, which means that the noted advantages reflect to a greater extent the expectations of its developers.

Boxer tank engine

Yes, there was such an engine, this is the 5TDF, developed for the T-64 tanks, as well as the subsequent T-72 and others. Then he provided the necessary power for the given dimensions. A similar boxer engine and its structure are shown in the figure below.

As can be seen from the figure, its pistons are located in one cylinder and move in the opposite direction, but each work on its own crankshaft. With a minimum distance between the pistons, a combustion chamber is formed between them, where the fuel is ignited. There is a boxer engine, both gasoline and diesel. By analogy with OPOC, turbocharging is used to supply air to the cylinders as well as to remove the exhaust gases.

The principle of counter movement of pistons used made it possible to simplify the design, ensure the power and compactness of the power plant. So, a similar diesel boxer power unit at two thousand revolutions, a volume of thirteen and six tenths of a liter, produced seven hundred horsepower, while taking up a minimum of space.

What is good and bad about oppositor?

It should be noted that in the history of the car, many manufacturers at various times have used the boxer engine, trying to realize the advantages provided to it. However, at the moment, SUBARU uses such motors more often than others on their cars.


It should be noted right away that it is the device of the opposed power unit that provides its advantages when installed on a car:

• low center of gravity of the car, which gives it additional stability when driving;
• reduction of both noise and vibration due to the movement of the pistons towards the opposite, due to which the boxer engine is considered quieter than similar in-line engines;
• a significant resource reaching a million kilometers with proper operation.

However, everything is not always good, there are also disadvantages and disadvantages of the opposed one. Of these, it is worth noting:

1. repair of such a motor is very difficult;
2. the engine device is also quite complex, and, accordingly, it has a high price;
3. maintenance costs are high, and the service itself is extremely costly and inconvenient, requires highly qualified performers;
4. increased oil consumption during operation.

Despite the noted disadvantages and disadvantages, a number of cars (the already mentioned SUBARU and some Porshe models) are equipped with opposed power units. One must think that manufacturers accurately weigh their advantages and disadvantages and consciously go for the use of such a motor.

For an internal combustion engine, the arrangement of the cylinders horizontally is only one of the possible construction options, but nevertheless, in this case, the resulting boxer engine is distinguished by great capabilities and significant prospects for use in a car.

One of the most common types of internal combustion engines is the boxer engine, which has been used for quite a long time in propeller driven aircraft, ships, ground installations, and automobiles. Similar units appeared in the 30s of the XX century. For the first time, such engines were used in cars by German and Japanese car manufacturers.

The design and principle of operation of the boxer engine.

The boxer engine is developed on the basis of a V-shaped unit, which has a camber angle of up to 180 degrees. Another feature of this unit is that it always has an even number of cylinders, which are located in two rows. However, the main principle lies in the process of operation of the unit itself. The fact is that the pistons of an ordinary in-line engine work in antiphase, while for an opposed one, the pistons are always in the same phase. This allows for faster revs and reduced engine vibration.

Pros of a boxer engine:

1. Narrow powertrain design to achieve a lower center of gravity. This is a big plus.

2. High smoothness of operation and good balancing of the engine. The fact that the pistons work in one phase helps to achieve this effect. Plus on the face.

3. Excellent engine design in terms of safety. In a severe collision, the engine goes under the car's bottom, protecting the driver from getting traumatic parts into the interior of the passenger compartment. This is also a very big plus.

4. The characteristics show excellent results.

Photo. Subaru motor

Cons of a boxer engine:

1. The permissible oil consumption is significantly higher than that of in-line motors.

2. Complex gas distribution and ignition system.

3. Maintainability. Most of the elements are in hard-to-reach places. This is an unpleasant minus.

4. The average engine resource is 120,000 kilometers.

5. The high cost of repairs.

Photo. Subaru.

Today, most car manufacturers (Subaru, Porsche, Volkswagen) with these engines have solved most of the issues that were voiced in the category of cons. Boxer motors have great potential, so further development will definitely continue and there will be much fewer drawbacks.

Interesting video: How it works? Subaru Technology

After the creation of the world's first internal combustion engine, it became necessary to improve it and increase its power. When the solution in the form of increasing the number of cylinders had exhausted itself, the search began for the optimal arrangement of the cylinders in the power unit. One of the most successful options was their horizontal arrangement, and an engine of this design began to be called opposed.

The device and principle of operation of the boxer engine

The main distinguishing feature of the boxer engine is the location of the pistons, the angle between which is 180 °. That is, the movement of pairs of pistons in it occurs in a horizontal plane. Each pair has its own camshaft, which together with the valves, unlike the usual inline engine, are located horizontally. This type of motor is widely used on cars manufactured by Volkswagen Group and SUBARU, they were equipped with Soviet motorcycles "Ural" and "Dnepr", the bus "Ikarus".

The horizontal arrangement of the cylinders reduces vibrations, mutually compensating for them, and achieve a smoother ride. As a result, the engine has the ability to smoothly build up power without noticeable jerks, while not wearing out so quickly. The boxer engine is located in the car near the chassis, which moves the center of gravity lower, thereby increasing the stability and handling of the vehicle.

Boxer engines are available in petrol and diesel versions. In modern versions of such power units, to achieve economical fuel consumption and environmental friendliness, the following technical solutions are used:

1. Reduced combustion chamber volume for higher compression ratio.
2. The use of forging technology in the manufacture of parts of the piston group, which reduces their weight.
3. Application of technologies for changing gas distribution phases.
4. The use of a new type of oil pump, thanks to which the engine is lubricated more efficiently.
5. A structurally new cooling system with 2 circuits: a separate circuit for the cylinder block and its head.

Types of boxer engines

Since its inception, the boxer engine has been improved for more than 70 years, which led to the appearance of its following modifications:

1. Boxer is a proprietary development of Subaru. It differs by the equal distance of the pistons from each other: when one is located at TDC, the second is at the bottom.

2. AERO. For a long period it was not in demand, but recently the engine has been installed on cars and is being improved. The design uses one crankshaft, and each cylinder has 2 pistons working towards each other.

3. Tank TDF. Used on tanks developed in the USSR. This is a two-stroke engine used only in military vehicles.

Boxer engine: pros and cons

The main advantages of the boxer engine:

1. Balanced operation and high efficiency. This is due to the horizontal arrangement of the pistons when they counterbalance each other. The most effective model of such an engine in terms of handling and balance is considered to be a boxer six.
2. Low center of gravity in the vehicle for increased stability. Such an advantage is not very useful for a city car, but it is very necessary for a sports car, for which stability at high speed is vital.
3. High reliability and durability. Most of the boxer engines are capable of working 500 thousand km before overhaul, which is much higher than the service life of the engines of many budget cars, including Volkswagen.
4. Compliance with high passive safety standards. In the event of a head-on collision, such an engine is displaced downward without harming passengers and the driver.

Weaknesses of opposites:

1. Unit design features that make repairs too expensive. Maintenance of such an engine requires high professionalism of the master, as well as the use of special equipment.
2. The large dimensions of the engine allow it to be installed only in the longitudinal direction.
3. due to the complexity of the design.

Difficulties in the repair and maintenance of a boxer engine

All the advantages of the boxer engine are fully revealed in the six-cylinder version of its execution. Units with fewer cylinders are practically the same as traditional ones. The main problem of the owner of an opposed car will be the complexity of maintenance due to the horizontal arrangement of the cylinder and the small free space under the hood for this reason.

The driver is independently able to replace the oil in it, and other types of work can be done only at the auto center. So, a simple replacement of candles should be carried out by a qualified specialist, and a beginner, performing this operation on his own, can damage the cylinder head. In the event of a malfunction, the repair of such an engine should also be carried out at a specialized service station.

The only thing that can be successfully carried out independently is to deal with carbon deposits on the parts of the piston group and the combustion chamber, which forms when using low-quality fuel, driving without load and on a cold engine. For this, a carbon removal technique is used, called decoking, which is divided into soft and hard. When hard, a softening liquid that destroys carbon deposits is poured through the hole from an inverted candle for 12 hours.

For a boxer engine, this method is not suitable, since unscrewing the candles in it is a rather problematic procedure, it requires skills and a special tool. But you can apply mild cleaning in the form of a special cleaning oil additive. A mileage of 200 km will be enough for its operation, after which the oil in the power unit must be replaced.

If your Subaru is on, it doesn't always bode well for costly repairs.

Prospects for the use of boxer engines

The most famous automakers using the boxer engine in their models are Porsche and Subaru. The first is experiencing a period of prosperity, and the second is not the best of times. This is due to the targeting of products to a different target audience: in the first case, Porsche cars are positioned as elite products, implying high manufacturability and cost of maintenance, and in the second, middle-class cars for those who like to have racing technology on a regular car.

For Porsche, customers are ready to give quite large sums of money, but for a car with an engine slightly exceeding 100 hp. with., which after running 130 thousand km. expensive repairs will be required, especially if it is turbocharged, only the most loyal customers can give preference. But taking into account the fact that many funds and developers are engaged in the improvement of opposites, as well as the fact that they are also used in motor vehicles, it allows us to remain confident that boxer engines will be relevant for a long time.

The boxer engine is a form of a device of an internal combustion engine of a car, which has a special structure: its pistons are located at a turned angle and move in a horizontal plane towards each other and in opposite directions (from each other). Another, adjacent pair of pistons is located in one position (for example, at the top).

The interaction of the pistons inside the engine is somewhat reminiscent of a boxing round, hence the other name for the device - a boxer. The design of the mechanism involves the installation of each piston on separate journals of the crankshaft. The number of cylinders in a boxer engine can be from 2 to 12, but always even. The most popular devices are with four and six cylinders (four- and six-cylinder boxers).

There are many brands of cars on the modern automotive market, each of which adheres to its own concept of equipping cars. Two companies are currently engaged in the development and application of boxer engines: Subaru and Porsche. Previously, the boxer engine was installed on cars such as Alfa Romeo, Honda, Chevrolet, Volkswagen, Ferrari and others.

The first boxer diesel engine was produced by Subaru in 2008. It is a four-cylinder boxer with a capacity of 2 liters, capable of developing power up to 150 hp. Its development uses the Common Rail system.

Some models of Porsche cars use six-cylinder engines (Cayman, 911). For sports cars, eight and twelve-cylinder boxer engines with increased power have been developed. Many professionals say that only six-cylinder boxers differ from the operation of conventional engines, four- and two-cylinder ones are almost the same.

Boxer boxer - basic principles of work

In general, the operating process of the boxer boxer is similar to the operation of other internal combustion engines. The main distinguishing feature of its design is the arrangement of the cylinders. The cylinders are installed horizontally, unlike most engines. This establishes another movement of the pistons: not up and down, but from right to left and vice versa (from one end of the cylinder to the opposite).

The original development of the horizontal boxer was not Subaru's, as many tend to think. Motors of this type have already been used earlier on Ikarus passenger buses, as well as on motorcycles (both domestic "Dnepr, MT" and foreign-made "enduro-tourist BMW R1200GS and others"). In addition, such engines have long been used in military vehicles, in particular, in domestic tanks.

Naturally, such an engine structure has its pros and cons. Let's consider them in more detail.

Benefits of a boxer boxer

Pictured is a Porsche boxer engine

The main advantages of an engine with horizontally located cylinders include:

1. Promotes a shift in the center of gravity. The mass is distributed around the axle, which greatly improves the handling of the machine. For many, this factor is decisive when choosing an engine and a car, this is especially true for Russian roads.
2. No vibration during operation. Engines with a standard structure and vertically arranged cylinders vibrate during operation, transmitting waves to the entire structure, which is not very comfortable for the driver.
3. Long work. The resource of the boxer boxer installed in Subaru is so great that it allows you to operate the car for a long time (it is enough for more than a million kilometers).

Disadvantages of a boxer engine

Pictured is a boxer engine Subaru Outback 2015

Despite the significant advantages, an engine of this type has significant disadvantages, which the developers have not yet got rid of:

1. Requires expensive maintenance. Often, ordinary engine repairs are carried out independently or in car dealerships for a small amount. However, in the case of a boxer boxer, this is not possible. Its design is too complicated, so it is better to entrust the installation to professionals. Moreover, for such services you will have to pay a decent amount of money.
2. The second drawback follows from the first drawback - even if there are sufficient funds for servicing this type of engine, difficulties may arise in finding a qualified specialist who can provide quality service.
3. The complexity of the boxer's device increases the cost of its component parts, which creates additional costs for repairs.
4. Increased consumption of automotive oil. A conventional engine consumes no more than three hundred grams of oil over the period of its operation, and an opposed engine consumes much more.

Thus, all the disadvantages of the device primarily lie in the high cost of its maintenance. This can be a significant factor for many car owners. However, according to representatives of the car companies Subaru and Porsche, the quality of its work is worth the money spent on maintenance.

Subaru is not going to change the boxer engines to standard ones, as its representatives tend to believe that this will be a big step back. The high cost of engine maintenance does not affect the level of sales of cars of this brand, since the cars have proven themselves exclusively from the positive side.