What should be the perfect engine in order to provide excellent driving? The answer is one - the horizontal Opposite engine Subaru.
To date, the opposite engine practically personifies this brand, although it is also used not only in Subaru, but also in the car of other brands, for example, Porsche (although much less often).
By the way, lovers of the Soviet Moto-Classics most likely remember motorcycles with an engine opposite arrangement, such as the "Ural" and "Dnipro" and, their characteristic sound of a working motor. The sound of the opposite engine is another feature and marketing advantage from car manufacturers.
Thus, Subaru makes it the sound and its racing achievements of a certain "highlight" of their cars, which distinguishes them from all the others, which, in turn, is most positively reflected on the sales of cars of this brand.
Principle of operation
The principle of operation of the horizontal-opposite engine Subaru is practically no different from the well-known engine internal combustion. Working clocks flow at the same speed as the vertical location of the engine.
disadvantages
- The most basic minus can be called the complexity of the repair of opposite engines. Some of these engines are not subject to repair at all, if you do not remove it motor compartment. No time without a specialized tool. If you do not want to spend a huge amount of time, contact professionals. It is worth remembering that for such a procedure will have to lay out a rather large amount, which is not surprising. After all, not every specialist knows the device of the opposite engine and its features;
- It is very difficult to find a specialized mechanic;
- A complex device requires large financial investments in terms of new details. That is, to buy the necessary part will have to lay out a large amount;
- Elevated oil consumption.
Benefits
Engine design, in which pistons are located on both sides of crankshaft At an angle of 180 degrees, creates a huge amount of advantages:
- With the horizontal arrangement of cylinders against each other, the inertia strength arising when the piston moves is mutually quenched. Due to which the engine has good equilibrium and low levels of vibrations.
- The low level of vibrations allows you to dispense with the abbreviations of a small mass and not to install balancing shafts. As a result, the engine consumes less fuel and has the best responsiveness.
- The low level of vibrations also makes it possible to obtain a large diameter of cylinders, which makes it easier to create high-breasted engines for sports cars.
- Inertia relative to the vertical axis of the car is less, which increases the speed of the response to management.
- The small height of the engine and the low position of the center of gravity additionally improve the speed of the reaction and increase the resistance of the car.
- The possibility of obtaining a large diameter of cylinders facilitates the creation of high-breed engines for sports cars.
- The design of the horizontal-opposite engine has a greater rigidity, which allows you to reduce mechanical losses when engine operation. Due to this, the engine resource increases.
Safety
Passive security. In the case of a serious frontal collision, a flat opposite engine is easier to go under the bottom of the car, thereby reducing the energy of the impact transmitted to the passenger interior.
Pedestrian safety. The opposite engine has a flat shape, leaving the space between the solid parts of the engine and the relatively soft hood. This makes it possible to efficiently absorb the impact energy at a walk on a pedestrian.
High stability with sharp maneuvers
The lightweight aluminum alloy engine has a low center of gravity, which provides a small inertia relative to the longitudinal axis of the car and small rolls.
The advantage of the low center of gravity can be demonstrated by the example of the metronome. If you stop the weight at the lower position, the pendulum will be swing fast. When permuting the weight in the upper position of the oscillation slows down. Thus, the advantage of a low center of gravity is brighter than all when high-speed passage of tight turns.
Controllability
The low center of gravity and the longitudinal location of the short engine allow the turn to reduce not only rolls, but also the moment of inertia relative to the vertical axis of the car, which has a positive effect on turning.
When the driver turns the steering wheel to change the direction of movement, the vehicle rotation center is closer to its rear. For cars equal to mass, fewer from the center of rotation to the center of gravity means easier turning. That is why the layout is preferably located with a low engine and longitudinally docked with a gearbox.
In contrast to the roll, which is a natural consequence of turning, the movement caused by the rotation of the steering wheel can be accepted for active movement, since it is specified by the driver.
In the example with the metronome, such active movement is similar to the fact that you stop the pendulum of the metronome and pushing it in the opposite direction. If the pendulum ship is in the lower position, you will need less effort in order to push it upside down.
The opposite is called the engine, the cylinders of which are horizontally relative to each other. A similar structure of the structure is name: a V-shaped engine with an angle of collapse of cylinders of 180 degrees. FROM of English language The word "Opposite" translates - "Located opposite". Consider the opposite engine - pluses and cons.
Features of the opposite motor
Despite the similarity with the V-shaped motor, the oppositor has nothing to do with it. The difference is that in the oppository, two adjacent pistons are located in one plane relative to each other. In a V-shaped piston engines when driving at certain points occupy the position of the upper and lower "dead point". In the oppository, they simultaneously reach either the upper "dead point" or lower. Such an improvement in the V-shaped motor was obtained by the location of the cylinders at the unfolded angle.
Another innovation was the location of gas distribution mechanisms in the vertical plane. All this freed the design of power units from imbalance and increased vibrations, and movement on the car made the most comfortable as possible. Now vibrations from the engine are not transmitted to the body and do not shake the car.
Opposite motors always have an even number of cylinders. Four and six-cylinder engines received the greatest distribution.
Features of the design of the Power Unit type "Boxer" have significant advantages over other types of motors:
The center of gravity is shifted down;
Economical fuel consumption;
Low vibration level;
enlarged motor resource;
passive security With a frontal collision.
Displaced down the center of gravity allows to achieve the best sustainability of auto and optimal controllability with active maneuvers and
Cool turns. During sudden turns, the roll is significantly reduced. The arrangement of the engine on one axis with transmission provides better power transmission. The absence of equilibrium shafts saves fuel consumption.
Engine runs in smooth mode. Low level Motor vibration is achieved due to the agreed rotation of the neighboring pistons. The location of the crankshaft on three bearings, instead of five ordinary, is another advantage of the opposite engine. This significantly reduces the mass of the engine and its length.
The arrangement of the pistons in the horizontal plane gives the system greater rigidity, which significantly reduces the mechanical losses during the operation of the power unit.
Passive security is ensured by the fact that when a collision, the motor easily goes down under the car. As a result, there is a decrease in the intensity of the strike on the passenger interior.
Increased cylinder diameter provides motor high revsWhat makes it possible to create a sports type model on this database.
Another feature is the characteristic sound when operating the opposite power unit: it is more pleasant for hearing.
Disadvantages of the opposite engine.
The advantages of the opposite engine are obvious. The disadvantages are:
Labor-intensive repair;
increased flow Motor oil.
To repair the engine, it is completely removed. However, this is not the problem. Details for replacement are very expensive, and the engine harvest delivers considerable headaches. If the driver can replace the candles on the repair of the row motor, then it is impossible in the oppository. Any repairs must be carried out on special equipment that is only available on a hundred.
The history of the occurrence of the oppository
Initially this species The power unit was used in the military industry, in particular, on domestic tanks. In the future, Ikarusi and motorcycle Dnipro MT went on such engines. At this time, the installation of the oppository to its products is engaged in two firms - Porsche and Subaru.
The first developments appeared in the thirties of the last century, when the engineers of the Volkswagen concern began to improve the V-shaped and row engine. In the sixties, the idea was intercepted by the Japanese company Subaru. In 2008, Subaru releases the first oppositor operating on the diesel. Distinctive features - four-cylinder engine with a capacity of 2 liters. Power indicator - 150 l / s.
Video Principle of Operation Support Engine Subaru
Despite the high cost of spare parts and service in a hundred, pleasure from riding a car equipped with the "boxer", not compare anything. High resistance, easy handling, the responsiveness of the car for all the actions of the driver speaks for themselves.
Differ from each other not only by the type of fuel consumed, but also by constructive features. For example, a large variety of cylinders. Each option has its strong and weak sides. IN this case The pros and cons of the opposite engine will be discussed.
IN piston engines Internal combustion (and there are also rotary) The placement of cylinders can be different in relation to each other: under an acute angle, in one row, star-like and so on. In the case of opposite cylinders are located in the same plane and placed one opposite the other at an angle of 180 degrees. Unlike many row engines, the opposite unit often has two, as well as a vertical distribution. There are several types of opposite engines. Among them are most famous:
- Boxer ("Boxer"). It is distinguished by the fact that pistons located in front of each other are moving like boxers in the ring. That is, when one of them is at an extreme top point, the second occupies an extremely lower position. They are equally removed from each other all the time;
- Oros - Opposed Piston Opposed Cylinder. The principle of operation in this case is that the pistons are pairwise in the same cylinder (upper and lower piston). They move towards each other, rotating the crankshaft.
- 5 TDF. This is a two-stroke tank engine of Soviet production, which was used on T-64 and T-72 tanks. An interesting feature of this unit consists in its multi-fiction. The main fuel for him is solard. However, using a special switch on a high-pressure fuel pump, it was possible to start the operating mode on gasoline or a mixture of gasoline with kerosene and diesel fuel, as well as the engine could operate on reactive fuel. True, it was also required to adjust the ignition angle (timing injection).
Many companies were actively engaged in the development of power units. For example, Volkswagen paid attention to this type of aggregates from the mid-30s of the last century. It was not just experiments, but the desire to develop their own opposite motor, reduce the level of vibrations that occur during the operation of the traditional V-shaped or row engine, etc. By the way, Volkswagen engineers applied their development in the legendary volkswagen car Beetle. And since the 60s, opposite engines have become actively used by Japanese company Subaru.which was engaged in developments in parallel with the Germans.
Advantages of Opposite DVS
By and large, the operation of the opposite engine does not differ from the principle of action of aggregates of other structures. However, such a layout of cylinders has its own advantages, as well as disadvantages.
- The most notable advantage of the considered power plants It is considered almost complete lack of vibration during operation. Such an effect is achieved due to the location that balable each other. This not only adds comfort, but also significantly increases the service life. From here there is a second "plus";
- An impressive resource of the opposite engine. There is evidence that quite often mileage until the first overhaul Mounted at least from 500 thousand kilometers. Of course, driving manner makes its substantial adjustments. And, nevertheless, the frequency period is quite large. However, the allegations of specialists and motorists can be found right and nearby, that 800-900 thousand to the first is nothing more than a beautiful fairy tale;
- Motors considered in this design article provide cars low gravity center. Especially this quality is valued in powerful sports cars. After all, passing the turns at high speeds, it is very important to maintain stability;
- It is also impossible not to mention saving space under the hood. Although many this item will seem controversial, because winning in height, you need to make the hood wider or longer.
Here, perhaps, all the essential advantages of oppositors. Now you need to consider the disadvantages, which, unfortunately, is somewhat more.
The main differences, as well as the advantages and disadvantages of 8th valve engines Compared with 16 valve engines. What force aggregate Better to choose.
From book V.N. Stepanov
Tuning automotive engines: SPb., 2000. - 82 p.: Il.5. Modernization of the exhaust gas production system
In a modern car, several important functions are assigned to the exhaust gas production system (OG):
- mild of noise when producing OG to a level not exceeding established sanitary standards;
- Reducing the number of toxic components in ogs to values \u200b\u200bnot exceeding maximum permissible concentrations.
Along with the execution of these functions, the release system must provide:
- good cleaning and purge of engine cylinders;
- minimal losses of exhaust energy on the way from exhaust valves to the vanes of the holling machine of the turbine;
- the work of the turbine with minimal pulsations of the exhaust flow.
In addition, the release system must have a relatively simple design and be technological in manufacturing. The fulfillment of these requirements allows to obtain an acceptable fuel consumption, reduce the likelihood of a breakwate of the turbine blades, reduce the metal-capacity of the release system and facilitate its maintenance.
The main problem with the desire to equip the car effective system The silence of noise is the difficulty of placing a silencer sufficiently large sizes. Usually this problem is solved by installing a car of several (up to three) sequentially connected silencers with smaller dimensions instead of one large. An important requirement for the graduation path is the presence of minimal resistance to the movement of exhaust and reduction due to this engine power loss.
To reduce the number of toxic components in the exhaust tract modern cars A catalytic neutralizer is installed. The feature of the developed constructions of catalytic neutralizers is that effective neutralization of the contained
In the excess of toxic components, they are carried out only with the value of the air excess coefficient α \u003d 0.994 ± 0.003. In order to determine the amount of oxygen-contained oxygen and correction (if necessary) the composition of the fuel-air mixture, ensuring the effective operation of the catalytic neutralizer, the feedback sensor is established in the graduation path, the so-called lambda probe, which is also called oxygen sensor. On some Toyota cars, such a sensor is installed both at the inlet of gases to the catalytic converter and at the outlet of it. This allows the control unit to evaluate the effectiveness of the catalytic neutralizer.
It should be noted that when installing a catalytic neutralizer, the resistance of the exhaust path inevitably increases, which is accompanied by some decrease in the efficient engine power (by 2-3 kW). In order for the overall resistance of the exhaust path during the installation of a catalytic neutralizer, the latter is usually placed on the place of the preliminary silencer. Since the maximum engine efficiency occurs when operating on depleted mixtures (≈α 1.05 ... 1,15), then the forced engine operation in the entire range of loads on the mixture of almost stoichiometric composition inevitably leads to a decrease in efficiency (up to 5%).The exhaust path of the system is striving to perform in such a way that when performing the main functions assigned to it, it would be able to more complete the combustion chambers from residual gases and a more complete filling of the engine cylinders with a fresh charge. Depending on the method of organizing the movement of the flow of exhaustion on the plot from the exhaust valves before entering the turbocharger turbine, exhaust systems are divided into systems
constant pressure
impulse
Pulse with pulse converters
Ejection single-tube.Graduation systems of constant pressure due to the existing serious flaws on automotive engines practically ne.
Apply.
The greatest spread here was pulsed and impulse systems with pulse converters. Consider these systems more.
Due to the cyclicity of the working process flow in the piston DVS in the graduation path, as in the inlet, there is an oscillatory movement of gases, as a result of which the pressure wave is formed.
Due to the large difference in gas pressure in the cylinder and the outlet path, at the first moment, from the beginning of the opening of the exhaust valve, a significant amount of gases comes out of the cylinder. During this period, called the preliminary release, a pressure wave of pressure propagated at the sound speed. This wave, reflecting from the walls of the exhaust pipeline, under certain circumstances can prevent the further flow of gas from the cylinder caused by a high pressure difference in the initial period of release. The subsequent cleaning of the cylinder from the residual gases is carried out in this case only by piston ejecting. Obviously, under such conditions, the number of gases remaining in the combustion chamber from the previous cycle will be the greatest. This will adversely affect the subsequent filling of the cylinder with a fresh charge and, accordingly, at the power, efficiency and environmental indicators of the engine.
However, the resulting pressure wave can be used to create for exhaust valve Conditions that contribute to improving the cleaning of the cylinder from residual gases. For this, the exhaust system must be configured so that by the end of the release process during the existing phase overlapping valves for the exhaust valve when the wave passes the vacuum was formed. This will increase the number of residual gases arising from the cylinder and improving the filling of its fresh charge. Setting the exhaust system is carried out by selection of length and secting area of \u200b\u200bexhaust pipelines. At the initial stage of work, the named output parameters can be pre-determined by the calculated method, but then the verification and refinement of the results obtained on the test bench are required. When performing these sufficiently laborious work in order to reduce the number of experiments to obtain the expected result, taking advantage of techniques known from the theory of experimentation planning.
The practice of designing exhaust systems shows that the more cylinders combines one exhaust pipeline, the smaller the resulting pressure amplitude resulting in the pipeline resulting from the imposition of individual waves. Therefore, in order to avoid unwanted overlapping of waves, the exhaust system is performed in the form of several fan (one over the other) pipelines, in each of which is the release of gases by no more than three cylinders. To prevent unwanted overlapping waves, gas flows from cylinders are combined by pipelines so as to provide an alternation of gas releases into each pipeline with the highest possible intervals. In this case, it is necessary to strive to provide the same length of exhaust pipelines (In practice, it is not always possible to implement due to existing dimensional restrictions). The execution of these conditions is possible with a fan-shaped arrangement of exhaust pipelines, when they are located one over the other. Ensuring the same pipeline length allows you to configure a system of output to a specific range of rotational speed. In the impulse exhaust system, the supply of exhaust to the turbine is carried out by individual pipelines from each group of cylinders.In a pulsed exhaust system with a pulse converter, pipelines, combining output from two or three cylinders, are transferred to the pulse conversion Y-shaped pipe, the two paths of which at a certain distance are combined into one. Compared to the classic impulse graduation system The pulse system with the pulse converter loses on dimensional indicators, but allows you to increase the efficiency of the turbocharger and increase the resource of the turbine.