Why does Subaru have such a distinctive growling exhaust sound? What is a boxer engine - the pros and cons of boxer sound

A boxer engine is an engine with a horizontal piston arrangement, that is, the pistons move horizontally relative to the car body. This arrangement is often found on Subaru engines,.

In an opposed engine, the pistons are located at an angle of 180 °, and their movement is in the same horizontal plane relative to each other. Adjacent pistons in a boxer engine are positioned the same in relation to each other. The second name of the "boxer" is "boxer", this name was given to the motors for the peculiarity of the piston movement, which resembles a boxer fight. The sound of a boxer motor is difficult to confuse with the sound of a conventional motor.

Unlike the classic V-shaped, in the boxer engine, each piston with a connecting rod is located on a separate connecting rod journal of the crankshaft. V-shaped motors have pistons and connecting rods on the same crankpin, so if one piston is at top dead center (TDC), then the other is at bottom TDC.

The main indisputable "pluses" of the boxer engine:

1. Minimal vibration during operation;
2. Low center of gravity;
3. High degree of safety in the event of a frontal collision. In the event of a frontal impact, the engine goes under the car, which allows the driver and passenger to survive in an accident and get out of it with minimal injuries.
4. Excellent stability, the car, which is called "road holding" and copes well even with the sharpest turns.
5. Flush alignment with the transmission ensures the most efficient power transfer.

At the same time, with all the above advantages, the boxer motor has another problem, due to the design feature, the inertial forces act on the motor, which try to turn it around the vertical axis. The weight of this type of engine is often much lower than that of V-shaped counterparts, this is achieved thanks to the installation

What do we know about the boxer engine? The fact that the pistons in it move horizontally. That this engine is the face of Subaru cars. Perhaps that's all. Let's find out a little more.

The boxer engine is one of the layouts of an internal combustion engine, in which the pistons are at an angle of 180 ° and move in a horizontal plane towards each other and away from each other. In this case, two adjacent pistons are always in the same position, for example at top dead center.

The movement of the pistons in the engine resembles a boxer fight, therefore another name for the boxer engine is boxer (boxer). A design feature of the boxer engine is the installation of each piston with a connecting rod on a separate connecting rod journal of the crankshaft. A boxer engine always has an even number of cylinders (2, 4, 6, 8, 10, 12). The most common at the present time four - and six-cylinder "boxer".

The boxer engine is not to be confused with the V-engine and 180 ° camber. With an outward similarity in such an engine, adjacent pistons with connecting rods are located on the same connecting rod journal. Therefore, when one piston reaches top dead center, the other is at bottom dead center.

The undeniable advantages of the boxer engine are a low center of gravity, minimal vibrations during operation and a high level of safety in a frontal collision.

The downward center of gravity of the boxer engine allows for better stability and control of the vehicle. The low-mounted engine is in line with the transmission for more efficient power transmission.

The boxer engine is almost completely devoid of vibrations (there is only a moment from the forces of inertia of the second order, tending to turn the engine around the vertical axis). Mutually coordinated movement of adjacent pistons ensures smooth engine operation. The mass balance in the boxer engine allows the installation of the crankshaft on three main bearings (instead of the usual five), which significantly reduces engine length and weight.

The boxer engine meets the requirements of passive safety to a greater extent. In a head-on collision, the engine goes down under the car and thus saves the lives of passengers in the cabin. An equally important advantage for drivers of the boxer engine is the characteristic sound of its operation, which differs from other internal combustion engines.

Unfortunately, boxer engine not without its drawbacks. The most serious, in our opinion, is the high labor intensity of repair work associated with the peculiarity of the engine design. So, to carry out individual repairs, the engine must be removed from the vehicle. Some sources note that the horizontal movement of the piston leads to uneven wear on the cylinder liner and, as a result, increased consumption oils. Given certain overall dimensions the boxer engine is only installed longitudinally on the vehicle.

Boxer engines are currently being developed and installed on their cars by Subaru and Porsche. Previously, the boxer engine could be seen on Alfa Romeo, Citroen, Chevrolet, Honda, Lancia, Toyota, Volkswagen and even Ferrari cars.

Subaru has been using boxer engines since 1963. These are four- and six-cylinder Boxer... Subaru's four-cylinder history goes back three generations: the series EA (1966-1994); series EJ (1989-1998, crankshaft with 5 main bearings, 1999-2010, crankshaft with 3 main bearings); series FB (since 2010). The six-cylinder Boxer went into production a little later - series ER (1987-1991), series EG (1992-1997), series EZ (since 1999).

The vast majority of boxer engines are gasoline engines with distributed fuel injection and an overhead gas distribution system. They have one (SOHC) or two (DOHC) camshafts, which are driven from the crankshaft by a toothed belt or chain. Despite the different number of camshafts, a four-valve gas exchange scheme is implemented in the engines. A number of engines are turbocharged.

The third generation four-cylinder Boxer is simpler, more compact, economical and harmless. To reduce fuel consumption, reduce toxicity of emissions, increase the magnitude of torque and expand its limits, a lot of progressive technical solutions have been used in new engines:

• increased compression ratio by increasing the piston stroke and reducing the volume of the combustion chamber;
• reduced weight of moving parts (connecting rod, piston, crankshaft) due to the manufacture of forging;
• on camshaftsx intake and exhaust valves used a variable valve timing system (active valve control AVCS);
• a new oil pump has been applied to ensure high quality lubricants and extending engine life;
• a cooling system with separate circuits is used to cool the cylinder block and the block head.

In 2008, Subaru first introduced diesel boxer engine... The four-cylinder 2.0-liter engine develops a power of 150 hp. It uses a common rail injection system, a turbocharging system with a variable geometry turbine.

A number of Porsche models (911, Boxster, Cayman) are equipped with six-cylinder boxer engines. At one time, 8 and 12-cylinder boxer engines were developed for use in auto racing.

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 of cylinder arrangements. Each option has its own strengths and weaknesses. In this case, the pros and cons of a boxer engine will be considered.

In piston engines internal combustion (and there are also rotary ones) the placement of the 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 an opposed cylinder, the cylinders are in the same plane and are placed opposite each other at an angle of 180 degrees. Unlike many in-line engines, the opposed unit often has two as well as 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 extreme upper point, the second takes the extreme lower position. They are all the time equally distant from one another;
• OPOS - 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 by rotating the crankshaft.
• 5 THF. This is a Soviet-made two-stroke tank engine that was used on the T-64 and T-72 tanks. Interesting feature this unit consists in its multi-fuel capacity. 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 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 required to correct the ignition angle (injection timing).

Many companies were actively involved in the development of power units. For example, Volkswagen has been paying attention to this type of unit since the mid-30s of the last century. These were not just experiments, but the desire to develop our own boxer engine, to reduce the level of vibrations that arise during the operation of a traditional V-shaped or in-line engine, etc. By the way, Volkswagen engineers applied their development to the legendary Volkswagen Beetle. And since the 60s, boxer engines have been actively used by the Japanese company Subaru, which was developing in parallel with the Germans.

Benefits of an opposed internal combustion engine

By and large, the operation of a boxer engine does not differ from the principle of operation of units of other designs. However, this arrangement of cylinders has certain advantages as well as disadvantages.

• The most noticeable advantage of the considered power plants almost complete absence of vibration during operation is considered. This effect is achieved through arrangements that balance each other. This not only adds comfort, but also significantly increases the service life. From here comes the second "plus";
• Impressive flat 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 turnaround time is quite long. However, all the time you can find the statements of experts 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 cars with a low center of gravity. This quality is especially appreciated in powerful sports cars. Indeed, when passing bends at high speeds, it is very important to maintain stability;
• Also, one cannot fail to mention the saving of space under the hood. Although this point will seem controversial to many, because winning in height, you need to make the hood wider or longer.

These are, perhaps, all the essential advantages of opposites. 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 motors compared to 16 valve motors... Which power unit is better to choose.

What should be the ideal engine to provide excellent driving experience? There is only one answer - Subaru's horizontally opposed engine.

Today, the boxer engine practically embodies this brand, although it is also used not only in Subaru, but also in cars of other brands, for example, Porsche (although much less often).

By the way, fans of the Soviet classic motorcycle most likely remember motorcycles with an opposed engine, such as "Ural" and "Dnepr" and their characteristic sound of a running engine. The sound of the boxer engine is another feature and marketing advantage for auto manufacturers.

Thus, Subaru makes this sound and its racing achievements a kind of "highlight" of its cars, which distinguishes them from all others, which, in turn, has the most positive effect on the sales of cars of this brand.

Principle of operation

The principle of operation of the Subaru horizontally opposed engine is practically no different from the well-known internal combustion engine. The working strokes proceed at the same speed as with the vertical arrangement of the engine.

disadvantages

• The main disadvantage is the difficulty of repairing boxer engines. Some of these engines cannot be repaired at all unless removed from engine compartment... Not yet without a specialized tool. If you do not want to waste a huge amount of time, then contact the professionals. It is worth remembering that for such a procedure you will have to pay a rather large amount, which is not surprising. After all, not every specialist knows the device of the boxer engine and its features;
• It is very difficult to find a specialized mechanic;
• A complex device requires a large financial investment in terms of new parts. That is, in order to buy the necessary part, you will have to pay a large amount;
• Increased oil consumption.

Benefits

The design of the engine, in which the pistons are located on either side of the crankshaft at a 180 degree angle, creates a huge number of advantages:

• With the horizontal arrangement of the cylinders against each other, the forces of inertia arising from the movement of the pistons are mutually extinguished. As a result, the engine has good balance and low vibration.
• The low vibration level makes it possible to dispense with the counterweights of a small mass and do not install the balance shafts. As a result, the engine uses less fuel and has better responsiveness.
• The low vibration level also makes it possible to obtain a large bore, which facilitates the creation of high-speed engines for sports cars.
• Less inertia about the vehicle's vertical axis, which improves responsiveness.
• The low engine height and low center of gravity further improve responsiveness and vehicle stability.
• The large bore capability facilitates the development of high-speed engines for sports cars.
• The horizontally opposed engine design has greater rigidity, which reduces mechanical losses during engine operation. This increases the engine resource.

Safety

Passive safety. In the event of a serious frontal collision, the flat boxer engine is more easily guided under the vehicle floor, thereby reducing the impact energy transmitted to the passenger compartment.

Pedestrian safety. The boxer engine is flat, leaving space between the hard engine parts and the relatively soft bonnet. This allows you to more effectively absorb the impact energy when hitting a pedestrian.

High stability during sharp maneuvers

The lightweight aluminum alloy engine has a low center of gravity for low inertia and low roll.

The advantage of a low center of gravity can be demonstrated with the example of a metronome. If you move the weight to the down position, the pendulum will swing quickly. When you move the weight to the upper position, the oscillations will slow down. Thus, the advantage of a low center of gravity is most clearly manifested in high-speed passage of a bunch of sharp turns.

Controllability

The low center of gravity and the longitudinal arrangement of the short engine make it possible to reduce not only roll when cornering, but also the moment of inertia relative to the vertical axis of the vehicle, which has a positive effect on steering.

When the driver turns the steering wheel to change direction, the vehicle's center of rotation is closer to the rear. For vehicles of equal mass, less center of rotation to center of gravity means easier cornering. This is why a low engine layout with a longitudinally mated gearbox is preferred.

In contrast to roll, which is a natural consequence of turning, movement caused by turning the steering wheel can be mistaken for active movement because it is driven by the driver.

In the metronome example, this active movement is similar to stopping the metronome pendulum with your finger and pushing it in the opposite direction. If the weight of the pendulum is in the down position, you need less force to push it to the other side.