Boxer engine: principle of operation, advantages and disadvantages Boxer engine: principle of operation, advantages and disadvantages. Subaru brand internal combustion engine What is better boxer or aspirated

Introduced in 2002, the novelty aroused great curiosity. Advantages and disadvantages boxer engine Subaru appreciates almost every motorist, even if he is not going to change his iron horse yet or prefers models from other manufacturers.

Fans of diesels are also showing interest, although the boxers are produced exclusively in a gasoline interpretation - the promised advantages are tempting for everyone. Those who, by definition, love Subaru products, want to know what they have to deal with, since the concern intends to equip its models only with such engines in the near future.

The idea has been developed since the 60s of the last century, but somehow sluggishly and without enthusiasm. Now she becomes the leader for the company.

The pros and cons of a Subaru boxer engine, of course, are determined by the features of its structure. The principle of operation remains the same, the engine has not gone anywhere from the idea internal combustion. But the design solution in it is original. And the opposites are applied only to Subaru and Porsche cars. Although not so long ago they were equipped with Honda, Alfa Romeo, Chevrolet, Ferrari, Volkswagen and a number of others.

What is a boxer engine?

In classic motors, the cylinders have a vertical orientation and move, respectively, in the direction: up - down. In the opposites, they are located horizontally, as a result of which the pistons go left - right. Since such a movement strongly resembles a fight in the ring, this type of engine was popularly nicknamed the "boxer".

Interestingly, the idea is not very original, but rather forgotten. Similar engines were on board the Ikarus and Soviet motorcycles like the Dnieper that had gone into oblivion, they were on some models of domestic tanks. Of course, Subaru developed a more advanced mechanism, but still they didn’t start from scratch at all.

Due to the horizontal arrangement of the cylinders, the engine seems more compact. However, this is an optical illusion: in terms of dimensions, it is similar to traditional ones, it just has a lower height. But the width exceeds the in-line engine by more than 2 times. Roughly speaking, it spread over the plane, which is why it looks smaller in size.

Favorable sides of the opposition

Subaru also brings small dimensions to them, but we have already figured it out, so we cannot agree with the company's opinion. The main advantage is given by the horizontal orientation.

Offset of the center of gravity. Firstly, it is underestimated compared to in-line engines. Secondly, it is distributed along the axis. This gives better handling and stability;
reduced vibration. Ordinary, even high-quality engines, to a certain extent, transmit vibration waves to the body and to the interior. In opposites, the vibration of one piston is smoothed out and leveled by the oncoming movement of the second;
Great resource. "Boxers" are theoretically designed for a run of a million kilometers. Whether this is so - time will tell, but I want to believe;
Enhanced Security. And it's been crash tested. In a head-on collision, conventional engines often go into the cabin, breaking the legs of the front riders. The boxer engine in a direct impact is displaced under the bottom, reducing the likelihood of a fatal outcome.

In fairness, let's say that all the advantages, except for the last one, are clearly manifested only on multi-cylinder engines. "Small sizes" with 2 and 4 cylinders practically do not differ from traditional engines in operation.

disadvantages

Perhaps it was they who led to the low prevalence of boxer engines. After all, many companies have gradually abandoned their use. And if oppositions are still found in sports cars, then in, so to speak, domestic ones are quite rare.

Engine self-service is practically reduced to zero. The complexity of its configuration leads to the fact that the owner himself can only change the oil himself. Even in order to replace or clean the candles, you have to go to the service station. Those who dare to do this on their own have a high probability of seriously damaging the cylinder head.
Maintaining a boxer engine car is much more expensive than a straight engine car. All autoworks are rated higher by the masters, the price of details is 2-5 times higher than those for “rowers”.
The boxer engine requires a catastrophic amount of oil. And if you reduce all the shortcomings to a single denominator, then we can say that they are too much money. That does not prevent people who have appreciated all the pros and cons of the Subaru boxer engine from giving preference to such models and still striving for the desired purchase.

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

The device and principle of operation of the boxer engine

Home hallmark boxer engine is the location of the pistons, the angle between which is equal to 180 o. That is, the movement of pairs of pistons in it occurs in a horizontal plane. Each pair has its own gas distribution shaft, which, together with the valves, unlike the usual in-line 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 allows to reduce vibrations, mutually compensating them, and to achieve a smoother ride. As a result, the engine has the ability to smoothly increase 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 control of the vehicle.

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

Reduced volume of the combustion chamber, increasing the compression ratio.
The use of forging technology in the manufacture of piston group parts, which reduces their weight.
Application of technologies for changing gas distribution phases.
The use of a new type of oil pump, thanks to which engine lubrication is performed better.
Structurally new system cooling, which has 2 circuits: a separate circuit of the cylinder block and its head.

Boxer engine types

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

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

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

3. Tank TDF. Used on tanks developed in the USSR. This two stroke engine used only on military equipment.

Boxer engine: pros and cons

The main advantages of the boxer engine:

Balanced work and high efficiency. This is due to the horizontal arrangement of the pistons, when they provide a counterweight to each other. The boxer six is considered the most efficient model of such an engine in terms of handling and balance.
Low center of gravity in the car, increasing its stability. Such an advantage is not very useful for a city car, but it is very necessary for sports cars, for which stability at high speed is vital.
High reliability and durability. Most of the boxer motors are able to work 500 thousand km before overhaul, which is much higher than the service life of the engines of many budget cars including Volkswagen.
Compliance with high standards passive safety. In the event of a frontal collision, such an engine moves down without harming passengers and the driver.

Weaknesses of Opposites:

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

Difficulties in the repair and maintenance of a boxer engine

All the advantages of a boxer engine are fully revealed in its six-cylinder version. Units with a smaller number of cylinders are practically the same as traditional ones in terms of characteristics. The main problem the owner of a car with an opposite will be difficult to maintain due to the horizontal arrangement of the cylinder and the small free space under the hood for this reason.

The driver is able to independently change the oil in it, and other types of work can be done only in the auto center. So, simple replacement candles must 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 on your own is to deal with soot on the parts of the piston group and the combustion chamber, which is formed when using low-quality fuel, driving without load and on a cold engine. For this, a carbon removal technique is used, called decarbonization, which is divided into soft and hard. With a hard one, a softening liquid is poured through the hole from the turned out candle for 12 hours, which destroys soot.

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 a mild cleaning in the form of a special cleaning additive to the oil. A run of 200 km will be quite enough for its operation, after which the oil in the power unit must be replaced.

If on your Subaru, this does not always portend an expensive repair.

Prospects for the use of boxer engines

The most famous automakers using a 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 focus of products on different target audiences: in the first case, Porsche cars are positioned as elite products, which imply high manufacturability and maintenance costs, and in the second case, middle-class cars for those who like to have racing technologies on a regular car.

For a Porsche, customers are willing to pay fairly large sums of money, but a car with an engine that is slightly more than 100 hp in power. with., which after a run of 130 thousand km. expensive repairs will be needed, especially if it is turbocharged, may be preferred only by the most dedicated customers. But given the fact that many funds and developers are engaged in improving the opposites, as well as the fact that they are also used in motorcycles, it allows us to remain confident that the opposed engines will be relevant for a long time to come.

Not everything is far away true, but from the negative points of the opposition here:

Let's go through now weak points subarovskih motors:

The geometry of the cylinders is subject to a curious feature - when the hone grid is in order, and the cylinder is already turning into an ellipse. However, aluminum cylinder blocks with cast iron liners and different expansion ratios have never been the ideal solution.

Oil consumption undermines engines regardless of age - in the same queue to the doctor are old cars from the first wave of foreign cars and people from car dealerships that still smell of fresh plastic. Here, the very horizontal position of the cylinders contributes to the intoxication, on occasion the turbine does not refuse its share of the snack, and, of course, the disease of the occurrence of the rings is standard (and for the new EJ205 this is not even a disease, but some kind of maintenance component). And try to unambiguously measure the level on a single unfamiliar Subaru engine oil. Happened? What about reverse side probe? And if the car roll back three meters to the side? Yes, it's a Subaru!
Well, what didn’t burn out, it ran away: oil seal leaks and “sweating” of covers are a generic feature of boxer engines.

The mass air flow sensor becomes covered with dirt or fails on machines of any manufacturer. Alas, the good old MAP sensors are a thing of the past.

Unification. It is not clear why a company that had only four main mass models should produce so many versions, updating them almost every year. For example, who remembers how many engines installed on the Impreza? Three four five? In fact, there were nine of them, in more than forty modifications. "Come on fix it"...

The timing belt is conveniently located on the opposite side, but “the elbow is close, but you won’t bite” - it runs around a lot of pulleys and rollers. If the SOHC option at a minimum attachments does not present any particular problems, then it is quite possible to miss a tooth or two when installing a belt on a DOHC engine, especially on a fresh engine with AVCS (phase change system). Everything would be fine, but the valves ... When the timing belt breaks, they meet the piston (or each other) and bend on almost all engines.

Crankshaft pins. It is easy to guess that the 4-cylinder boxer naturally assumed three crankshaft bearings, but that was in the past ... In order to increase rigidity and slightly reduce loads, the Subarovites increased the number of bearings to five, but, as in the old parable about ten hats from skins, miracles did not happen. The necks here are still narrow, so the specific load and wear are greater than on inline fours, and their repair is too difficult - you can’t regrind them on any kind of equipment now.

Hydraulic lifters earlier (until about the mid-90s) were highly respected by Subaru, but then common sense prevailed. So the pleasure of pumping a dozen and a half "mushrooms" in a bowl of kerosene is now not available to everyone ...

crankcase ventilation. It is difficult to recall engines where its clogging just as "quickly and efficiently" led to a service. If conventional motor at least try to puff, spit oil into air filter, knock out the probe - then the Subarovsky opposite with gloomy samurai tenacity will immediately begin to squeeze out the oil seals ...

Assembling a gutted boxer is an epic picture. Correctly clamping the crankshaft between the half-blocks is not for you to pull the crankshaft caps. Well, to combine the hole in the piston with the hole in the connecting rod and with a special hole in the block, then put the piston pin there and “polish” everything with the retaining ring - this is a song (for a six-cylinder EZ30 boxer, in general, a poem)! Okay, if it was a racing monster of three hundred to five hundred forces, then such sophistication could be forgiven. But when the same work is required by a hundred-strong buzzer of some kind of Impreza, the sanity of Japanese engineers is a big question.
You don’t have to remind that for more or less serious work on mechanics, the engine must be removed from the car (and the DOHC engine is a must). The argument about the ease of removal of the Subarovsky engine compared to any kind of row is true - but only in most cases this row would not have to be dismantled at all.

Radiators leak massively from any Asian automakers. There is a feeling that plastic radiator tanks for Japanese and Korean cars are driven by the same scumbags, with the same violations of the technical process or design. But ... If Toyota has a different probability of failure of radiators (for example, with S-series engines, unfortunately, this happens more often than with A-series on the same models), then the entire small range of Subaru cars irrigates the ground with antifreeze evenly .

That's what you can't help but praise the Subarovskie SOHC engines- so this is for the availability of the intake tract and fuel system. BUT fuel filter? Not Toyota, with forever soured nuts and hidden somewhere deep in the bowels engine compartment, but easily accessible, on hoses and clamps.

"Engine - millionaire"

The fantastic resource of Subarovskih motors is nothing more than a beautiful legend. Plus, they are very, very different...

"Normal"
Small displacement engines (EJ15#, EJ16#, EJ18#) are far from "millionaires", although they are quite efficient and reliable - normal motors for C-class cars. From the point of view of the manufacturer, unification with the big brothers is understandable, that's just ... Well, why does a normal person need a modest motor of such a wild layout? Even one and a half liters are supplied with two block heads and "features" of servicing the opposites.

The best and optimal Subar engines are two-liter SOHC (EJ20E, EJ20J, EJ201, EJ202 ..). Here, some problems are at least compensated by the return, and the resource and power are in a reasonable balance - in terms of reliability, they are not inferior to in-line Toyota fours of the same volume. Designed for the 92nd gasoline, they have a moderate appetite, and although they will deliver a lot of "pleasant" minutes during repairs, they are very simple to maintain. In the segment of 200-250 thousand mileage, they require a standard bulkhead with the replacement of rings (without boring), after which they receive a "second life" for a while.

"Medium"
Two-liter naturally aspirated DOHC EJ20D, EJ204 ... engines are actually the last engines with a real margin of safety, but four camshafts for four cylinders are already too much. Maintenance becomes difficult: changing spark plugs is a problem, when installing a timing belt, the probability of an error is several times greater, all work on the mechanical part is only after removing the engine, gasoline is 95th ...

"Trash"
First of all, these are turbo engines. Although why rubbish ... They fulfill their task - to give all their best with maximum tension for several thousand kilometers and "exhaust themselves". If the operation of the type "fixed - driven - for repair" is chosen consciously, then there are no questions. But for a "civilian", and even more so for an everyday car, they are not suitable, so the hopes of some to get both a powerful and tenacious engine are naive.
EJ20G, EJ205 - basic turbo engines with a resource of 100-150 thousand. Here are just a "revival of the bulkhead", similar to normal or at least atmospheric Subarovsk engines, does not always work. Usually, turbos end their days with decommissioning - after a broken connecting rod, destruction of pistons, emergency wear ...
EJ20K, EJ206, EJ207, EJ208 - turbo monsters... and non-residents, for whom even 100 thousand will be a great result. Often these cars are already killed by the first owner - of course, that the Japanese scumbag paid twenty or thirty thousand for his crazy stool not so that it would gather dust in the garage, waiting for its buyer from cold Russia.

Secondly, the DOHC EJ254 engine is certainly remembered, the most problematic aspirated (along with the EJ22) - due to inevitable overheating. In stock for this engine it would be nice to have a box of gaskets, a rack of heads and a surface grinder for regular editing of warped planes. After it was discovered that the EJ254 cannot be actively released to the foreign market (they will sue), its deformed brother SOHC EJ252 appeared. But in any case, Subarovskie 2.5s traditionally turn out to be much more capricious than their 2-liter counterparts.

Outcome? If Subaru engines really were as great as they sometimes say, then they would not have problems characteristic of others and would not have specific ones, but alas ... Yes, Subars are usually equipped with more powerful engines, than others Japanese cars of the same class - this is the only real advantage of cars with boxers. Otherwise, they not only do not exceed, but are often inferior in reliability and survivability to other Japanese brands.

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 ( crankshaft they, like the V-shaped ones, most often have one). 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 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 the value of their mileage up to 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 famous Japanese firm 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.