Diagram of an opposed internal combustion engine. Boxer engine, advantages and disadvantages

The boxer engine is not just a technique that was ahead of its time, but in fact the solution to many problems that are not able to solve many modern traditional engines.

What is a boxer engine? Video

The boxer engine is a special type of power plant that resembles a traditional engine itself, but the cylinders are located horizontally. In common people this motor received the name "boxer". This is due to the movement of the pistons away from each other, or towards each other, towards each other. However, the two pistons are in the same position.

The first example is an engine from Volkswagen in 1938. At that time, the unit consisted of a 4-cylinder "boxer" with a volume of 2 liters, with a capacity of 150 Horse power... After that, the motor gained popularity and began to be widely used.

Subaru boxer engine

Today, boxer engines are manufactured and installed by Subaru and Porsche. Until recently, this fate was also shared by Toyota, Honda, Ferrari, and of course, the founder of boxer engines - Volkswagen. Such installations can be seen not only in motorcycles, Ikarus buses, but also in some tanks.

Video about the Subaru boxer engine:

The principle of operation of the boxer engine. Video

To form a final picture of what the boxer engine is, you need to understand its structure. Let's repeat what was said earlier - this is an internal combustion engine, which has one feature - the movement of a pair of pistons is performed in a horizontal plane ... The second pair in the neighborhood is also in a horizontal position.

The total amount of such cylinders can reach 12, of course, counting starts from 2. The number will necessarily be a multiple of two. The most popular designs are 4 and 6 cylinders. Experienced mechanics and professionals noted that the operation of the 2-cylinder and 4-cylinder boxer is not too different from the traditional engine. Features begin to emerge from six cylinders.

Video of the principle of operation of the Subaru boxer engine:

A variety of boxer engines

It will not be news that the principle of operation itself depends on the features of the type of unit. This also applies to boxer engines.

They are divided into:

1. Boxer boxer, which are often used in Subaru cars. As for the principle of their operation, it should be said that the pistons are located at a predetermined distance from each other, at the same distance from the engine axis. But at the same time, each piston is located separately from each other in the cylinders. This principle of operation is similar to boxing fights, hence the name;

   
   Boxer Engine - Boxer. Photo

2. OROS radically differs from the boxer, both in structure and in the sequence of pistons. These units are two-stroke. One of the cylinders is located just behind two pistons that are attached to a single crankshaft. One of them is responsible for the intake of the mixture, the second - for the timeliness of the release of combustion products. In this design, there is no head, which in most cases is located on the cylinder block. TO the benefits of OROC engines refers to the fact that the pistons "work on one crankshaft." This is what makes it possible to create these engines of small size and weight. This leads to a wider scope of their application. Also, this engine works in the same way that on diesel fuel that on gasoline. With all this, the pistons travel much less distance, and therefore the friction force is several times less, which prolongs the life of the engine. And also, given that it has a smaller size and weight, therefore, two times fewer parts are required for its manufacture. This saves money. Common Lack of ODA engines is that they were not so long ago developed and are being improved to this day. Because of this, unforeseen problems should not be ruled out during its operation;

   
   ОROS is a boxer engine. Photo

3. ... The boxer engine is also designed to operate large military equipment. In this case, the pistons divide one cylinder and move in the same direction, but each has its own crankshaft. The combustion chamber is created at that moment of the minimum distance between the pistons. The similarity with OROC is that air enters the cylinders themselves, and excess gases are removed by turbocharging. This power plant has a capacity of 700 horsepower, the maximum number of revolutions is 2000. The volume is equal to six or thirteen liters.

   
   Tank boxer engine. Photo

Pros of boxer engines

Regardless of the type of motor, boxer engines have common advantages, among which are:

Cons of boxer engines

Of course, there is nothing perfect in the world, which can be said about boxer engines. The disadvantages include:

• A very large amount for service that requires the intervention of professionals;
• High cost of spare parts;
• The complexity of the entire structure as a whole;
• Higher oil consumption during operation.

But even taking into account the above disadvantages, this does not prevent many manufacturers from installing boxer engines on their cars. Before that, all the pros and cons are weighed.

Chief among the pluses is more opportunities and broader perspectives. After all, in fact, all the shortcomings run into money. However, most people are aware of the fact that more money is required for good quality. In addition, the use of boxer engines is the next step in technological development.

Differences between a boxer and in-line four-cylinder engine

Now we will talk about the general features and distinctive features of the Boxer Four and Straight Four in-line and boxer four-cylinder engines. And also about their pros and cons. Below is a short video where everything is described in detail.

Differences between a boxer and in-line four-cylinder engine. Video

1. Both designs operate on the principle of a four-stroke cycle - start, compression, stroke and release.
2. In both designs, a working stroke occurs every 180 degrees of rotation of the number of shafts, but they have a slightly different ignition order.
3. On each engine we see cylinders numbered 1, 2, 3, 4. For the opposite ones, the ignition order is 1, 3, 2, 4., and for the inline 1, 3, 4, 2. So the order of operation of the last two cylinders is changed ... This difference affects how the engine is balanced. On a boxer engine, the cylinder pairs, outward and inward, move together. This means that the first-order inertial force that occurs when the piston reaches top or bottom dead center cancels out. It's the same story with an in-line four-stroke engine - the first order inertia forces cancel each other out, as for the second order inertia force - here the engines start to differ. Second-order inertia forces are created due to the fact that the piston moves faster at the top of the cylinder than at the bottom. When the piston reaches its maximum or minimum dead center, the second order inertial forces are directed up or down from the piston. In a boxer engine, because the pistons are opposite each other, these inertia forces are balanced to ensure smooth engine operation. In an in-line four-cylinder setup, all forces are directed in one direction, which causes the engine to vibrate if the balance shafts are not used.

But still, the boxer engine is not ideal, due to the fact that the pistons are not in line with each other, torque is created, which contributes to the rotation of the engine along the vertical axis.

BTW SPEAKING! If you add two cylinders to any of the designs, be it a boxer or in-line six, all the inertial forces of the torque will be compensated.

You probably thought that a boxer six would vibrate due to a group of 3 pistons, but each group of three pistons balances the vibration of the other group. If we compare the dimensions of the engines Subaru EJ20 2.0L Boxer-4 and Toyota 22R-E 2.0L Inline-4, then they are almost the same, with this configuration, the engines usually do not have a volume of more than three liters, but before they were produced much larger volume.

The largest modern inline-four is a gasoline engine from Toyota car Tacoma, volume 2.7 liters.

But this does not mean that the inline four does not have its own advantages:

1. It is generally more compact, has only one cylinder head and is not as wide. This leaves more room for suspension and allows for a smaller turning radius as the car's tires have more room to turn.
2. In terms of timing, this particular inline-four has a single overhead camshaft, but more often in modern cars there are two camshafts.
3. The big advantage of an inline-four is that it has only one cylinder head, one intake and one exhaust camshaft, fewer moving parts, less weight, and it's much easier to reach the cylinder block for maintenance, whether it's adjusting valves or replacing plugs with inline configuration is much easier to do.

Finally we got to the topic of engine sounds. Many people claim that boxer engines sound better, but this is not really an advantage. This sound is due to the different lengths of the tailpipes.

And since Subaru has ditched this exhaust design, the new boxer fours will sound just like the rest of the four-cylinder engines. It is of course possible to create an exhaust system with tailpipes that are of different lengths to obtain a unique exhaust sound. But this can worsen the purging of the cylinder due to unequal pulsations, and there is no particular sense in this. However, when it comes to a boxer engine, fitting different lengths of tailpipes seems attractive.

Difficulties in the repair and maintenance of boxer engines

As mentioned earlier, if you need to carry out any manipulations on the engine, you cannot do without the help of a specialist. In opposition engines, without consequences, it will only be possible to change the oil with your own hands.

One of the factors that has a significant impact on the service life is the timely and systematic decoking. This procedure cleans the combustion chamber, valves and pistons from accumulated carbon deposits. It is best to carry out this procedure in the fall or early spring. It is during this period that it will be reasonable to check the oil with its changeable.

A common man in the street who is interested in cars does not know much about the boxer engine. Basically, only that the cylinders in it have a horizontal arrangement and such a motor is installed on Subaru. Let's try to expand the horizons of our knowledge and talk about boxer engines.

A boxer engine is an internal combustion engine layout in which the pistons are parallel to the surface in a horizontal plane. In this case, two adjacent pistons are in different positions relative to each other at the same time. Their movement is very similar to a fight in the ring, and motors are often called boxers. One of the distinguishing features is the mounting of each piston on its own crankshaft connecting rod journal. In this case, the number of pistons is always divisible by two. The most popular are four and six cylinder boxer motors.

Some confuse boxers with a V-shaped engine. Despite some similarities in design, there are significant differences. So in the V-shaped, adjacent pistons are on the same connecting rod journal and, when moving at the same time, are at opposite points of the work stroke.

The following advantages of this type of engine can be distinguished:

• low center of gravity;
• reduced working vibrations;
• increased safety in a head-on collision.

Each of the benefits has its own rationale. So a lower center of gravity means better vehicle handling and traction, and the lower position of the engine puts it in line with the gearbox, which significantly improves the efficiency of the transfer of revolutions.

The boxer motor has reduced vibration due to its layout. This allows it to be installed on a crankshaft equipped with three main bearings, and not five, as is usually the case. At the same time, it is possible to significantly reduce the dimensions and weight of the entire structure.

High security is also dictated by a low location. In a head-on collision, the engine goes under the passenger compartment, which ensures the survival of passengers in the front seats. And, in the end, the boxer engine has a characteristic sound, which is not at all similar to the sound of a conventional engine.

Nothing happens without flaws, the boxer engine also has them. These include:

• sufficient difficulty of repair work due to design features. Often there is a need to dismantle the engine in order to carry out certain work.
• craftsmen note different wear of the cylinders due to the horizontal arrangement of the pistons and the further high use of oil.

Today, the boxer engine has become the hallmark of brands such as Subaru and Porche. Previously, it could be seen on cars of various brands originating from Germany, USA, Japan, Italy.

Subaru has been putting these engines on its cars since 1963. The four-cylinder comes in three generations: the EA, EJ and FB series. The six-cylinder steel on the conveyor is somewhat later, but also have three series: ER, EG and EZ.

Most engines of this type run on gasoline and have distributed fuel injection with an overhead valve timing system. There are motors with one (SOHC) or two (DOHC) camshafts, driven from the crankshaft by a belt or gear drive. In all motors of this type, the gas exchange scheme is based on four valves. There are also turbocharged boxer engines.

The third generation of engines is today the peak of engineering, which is small in size, simple in design, low fuel consumption and reduced emissions into the atmosphere. To achieve all these indicators, the following was carried out:

• increased compression ratio of the mixture by increasing the piston stroke and reducing the volume of the combustion chamber;
• parts have become much lighter due to their implementation by forging, rather than casting;
• the variable valve timing system (AVCS) was put into operation;
• engine resource and lubrication quality are increased due to a new oil pump;
• Cooling is done separately for the engine head and cylinder block by means of a secondary circuit, which increases efficiency.

2008 saw the first appearance of a diesel-powered boxer engine introduced by Subaru. It has 4 cylinders and 150 hp. Its layout uses a progressive injection and turbocharging system.

Porshe also mounts boxer engines on some of its models. These are 911, Boxter, Cayman. They use six-cylinder motors. Eight and twelve-cylinder boxer motors have also been developed for cars that are racing.



Video about Subaru boxer engines:

The device and features of Subaru boxer engines:

Troubleshooting and review of the opposed internal combustion engine Subaru EJ257 2.5l. turbo (video, lecture):

Modern reciprocating internal combustion engines (ICEs) 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 the cylinders, everything is not so obvious. In this article, we will look at 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, and where it is used.

The design and features of the boxer engine

The diagram of the boxer engine

Opposed internal combustion engines are called, the camber angle of the cylinders of which is 180 °. The pistons in them move in a horizontal plane, moreover, mirror-like in relation to each other. This means that they reach their highest point at the same time. By the way, this is one of the main differences between opposed power units from the more common V-shaped ones: in them, the pistons move synchronously (when one of them is at the top point, the second is at the bottom).

Thanks to this arrangement of cylinders, the boxer engines have a low center of gravity. In addition, their height is significantly less than that of the V-shaped, they are "flatter" 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 have one crankshaft, just like V-shaped ones). As for the principle of operation of these engines, it is exactly the same as for 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

Today there are three main types of boxer engines:

• Boxer;
• OPOC;
• 5 THF.

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 movement of boxers in the ring, they got the name Boxer.

OPOC. This abbreviation stands for Opposed Piston Opposed Cylinder, and the design feature of this type of boxer engine is that there are two pistons in each of the cylinders. They move towards each other. OPOC type boxer engines are two-stroke, they do not have cylinder heads and valve actuators. Thanks to this design, these power units are lightweight, and they are both gasoline and diesel.

5 THF. 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 the opposed OPOC 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 run on both gasoline and diesel fuel. Now these power units are no longer produced.

Pros and cons of boxer engines

Boxer engine crankshaft and pistons

Like other types of internal combustion engines, boxer powertrains have both pros and cons. As for the pluses, one of the most significant of them is the very low level vibrations during operation. This is what these motors owe to the opposed 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-shaped engines. Accordingly, the resource of such motors is very large: practice shows that the value of 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 power units of this type 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 vehicle stability. In addition, as mentioned above, their low height can be considered an advantage of motors of this type. 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 precision in the manufacture 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. Diagnostics and troubleshooting of boxer engines is possible only with specialized equipment and specially trained personnel. It goes without saying that even minor repairs to such motors are not cheap for the owners of the cars on which they are installed.

Also, a significant drawback of boxer engines is considered a significant oil consumption. However, in terms of fuel consumption, they are still inferior to modern V-shaped and in-line power units.

Scope of application of boxer engines

Boxer engines are not nearly as widely used as V-shaped and in-line engines, but there is an automaker that has been installing these types of motors on their cars for half a century. This is a well-known Japanese firm 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 on the improvement of OPOC boxer engines, carried out by a group of American engineers, is funded by Bill Gates.

Video on the topic

One of the most interesting internal combustion engines: boxer engine operating principle, its design features, advantages and disadvantages.

The boxer engine is a design with two rows of cylinders horizontally located relative to each other.

The palm in the development of this type of engine is automobile concern Volkswagen. Its development was completed back in 1938 and it was installed on the most legendary in the world, the people's car Volkswagen Käfer.

Volkswagen is currently putting a boxer engine on the prestigious 997 Porsche cars

In the forties of the last century, the Japanese concern Subaru (SUBARU) also developed an opposed engine design. He also advanced in his developments and today equips a whole range of engines with such engines.

In developing this design, the engineers sought to lower the vehicle's center of gravity, thus achieving greater stability.

Features of the boxer engine

The main feature is the arrangement of two rows of cylinders, strictly in the same plane, at an angle of 180 degrees relative to each other.

There are several types of boxer engines:

• OPOS - Opposed Piston Opposed Cylinder in translation Opposite piston cylinder... The idea of ​​this design involves the movement of pistons towards each other, being in one cylinder;

• Boxer - Boxer. Classic modern boxer engine. The pistons are like boxers in the ring, alternately waving their fists, then one, then the other. One at top dead center, the other at bottom dead center and always equidistant from each other;

• 5TDF. This is already a domestic development. This boxer engine was made for the T-64 and T-72 tanks. Its design is special, it is two-stroke, has two crankshafts and pistons move towards each other.

Boxer engine advantages:

• The first and foremost advantage is that there is almost no vibration. The movement of the pistons in different directions maximally balances the forces that arise when the vector of movement of the pistons changes. This affects not only comfort, but also the service life of such an engine;
• Resource. It is this arrangement of the cylinders that gives the boxer engine a surprisingly high resource. They nurture over 500 thousand km. You can find a lot of SUBARU cars with a mileage of up to 900 thousand km. without major repairs;
• Center of gravity. This is very popular with sports car designers. A low center of gravity naturally gives more stability and is extremely useful for racing, although this advantage is equally appreciated in production cars;
• More space under the hood. Although this is compensated for by the inconvenience of having to free up space on the sides in order to assemble it without greatly expanding the hood and front suspension.

Boxer engine disadvantages:

• High maintenance cost. Even spark plugs cannot be replaced at home. If we talk about the most common brand of boxer - Subaru, then among its various engines there is practically no interchangeability of parts;
• A very complex overhaul. Due to the unusual and original design, repairs are carried out only in specialized workshops, of which there are not so many;
• High consumption engine oil, which is related to the construction of the opposed. And of course, the crankcase clogs up faster, due to the large oil flow through the engine.

//www.youtube.com/watch?v=9LBEK-uw7cE

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. The development and application of boxer engines are now engaged in two companies: 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

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

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

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, it may be difficult to find 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 during its operation, and an opposed one is much more.

Subaru does not intend 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.