Cars of the Volkswagen-Audi concern are quite common in Russia. One of the features of these machines is turbocharged engines. And if earlier the turbine could only be found on diesel engines, then VAG uses it everywhere on gasoline engines.
The purpose of modernization is to maximize the technical characteristics of the unit while maintaining its working volume. Since fuel efficiency is important today, it is impossible to increase the volume of the combustion chamber indefinitely. Therefore, automakers go to different tricks. A striking example of such work is the TSI engine. What is it and what are the features of this power plant? Let's take a look at our today's article.
Characteristic
The TSI engine is a gasoline power unit that is used in Volkswagen, Skoda and Audi vehicles. A characteristic difference between the TSI engine is the presence of a double turbocharger and a direct fuel injection system (not to be confused with the Common Rail). Having developed a special design, German engineers achieved high fuel efficiency of the unit with good technical characteristics.
The first TSI model appeared in 2000. This abbreviation literally translates as "double supercharging layered injection."
Line of units
It is quite extensive, and motors with the same displacement can produce different power. A striking example of this is the 1.4-liter TSI engine. 122 horsepower is far from the boundary threshold. The concern also produces 1.4 TSI engines for 140 and 170 horsepower. How is this possible? It's simple: the differences lie in the boost technology:
- when using one turbocharger, the power of the TSI 1.4 engine varies from 122 to 140 horsepower;
- with the use of two turbines, the power increases to 150-170 forces. This changes the software of the electronic engine control unit.
And all this on a motor with a working volume of 1.4 liters! But this is far from the only motor in the lineup. There are different variations of TSI engines:
- 1.0TSI. This is the smallest motor. It is equipped with one turbine and develops a power of 115 horsepower. The TSI liter engine has only three cylinders.
- 1.4. We have already talked about these motors above. The line has five variations of engines with power from 122 to 170 horsepower. All cylinders are arranged in one row.
- 1.8. Such motors have three modifications. The power of this power plant can range from 152 to 180 horsepower.
- 2.0. These units develop power from 170 to 220 forces. The engine block is in-line, four-cylinder (as on the previous two units).
- 3.0. This is the flagship engine used on the Volkswagen Tuareg. This is a six-cylinder V-type engine. Depending on the degree of boost, its power can range from ZZZ to 379 horsepower.
As you can see, the range of power units is quite extensive.
Device
It is worth noting that the TSI engines have been significantly redesigned. So, an aluminum cylinder block, a modified intake and exhaust system, as well as an upgraded fuel injection system are installed here. However, first things first.
Superchargers
The turbine is the main element thanks to which such high technical characteristics are achieved. Superchargers on TSI motors are located on different sides of the block. The mechanism is powered by the energy of exhaust gases. The latter set in motion the impeller, which, through special drives, pumps air into the intake manifold. Note that conventional turbocharged engines have a lot of disadvantages. In particular, this is the effect of a turbo lag - the loss of torque of the internal combustion engine at its certain speeds. TSI motors are free from this disadvantage thanks to several superchargers. One works at low speeds, and the second is connected at high. This is how the maximum torque is realized in a fairly wide range.
How does boost work?
Depending on the number of revolutions of the crankshaft, the following modes of operation of this system exist:
- Naturally aspirated. In this case, the turbine is not involved in the work. Engine revolutions do not exceed one thousand per minute. The throttle control valve is in the closed position.
- Operation of a mechanical blower. This mechanism is activated when the revolutions are from one to two and a half thousand per minute. A mechanical supercharger helps provide good torque when starting the car from a standstill.
- Combination of turbine and supercharger. This happens at a speed of two and a half to three and a half thousand.
- Turbocharger operation. The blower no longer starts up. Supercharging is provided only by the turbine impeller in the speed mode of three and a half thousand and above.
As the RPM increases, the air pressure also increases. So, in the second mode, this parameter is about 0.17 MPa. In the third, the boost pressure reaches 0.26 MPa. At high speeds, the pressure level decreases slightly. This is done in order to prevent the effect of detonation (spontaneous ignition of the gasoline mixture, which is accompanied by a characteristic blow to the piston crown). When the turbocharger is operating, the pressure level is 0.18 MPa. But this is quite enough to provide high torque and power when driving at speed.
Cooling system
Since the engine is in constant load mode, it needs high-quality cooling.
So, the system has pipes that pass through the intercooler. Thanks to this, cold air enters the cylinders. This ensures a more complete combustion of the mixture and contributes to an increase in engine dynamics.
injection system
The TSI engine has an upgraded injection system. It belongs to the immediate type. So, fuel enters the chamber immediately, bypassing the classic fuel rail. As noted by the reviews, the work of direct injection is felt when accelerating. The car literally undermines from the bottom. But the use of such an injection system is aimed not only at increasing the efficiency and power of the engine, it helps to reduce engine fuel consumption.
Cylinder block
The TSI engine features a lightweight aluminum cylinder block. The use of such an alloy significantly reduced the mass of the motor. On average, such a block weighs 14 kg less than cast iron. Also, the design uses other camshafts hidden behind a plastic cover. Thus, high operational performance of this internal combustion engine is achieved.
Problems
What problems do TSI engines have? One of the common diseases of these power plants is increased oil consumption. Moreover, the maslozhor is not uncommon even on new engines. What do reviews say about 1.4 TSI engines? These units consume up to 500 grams of oil per 1000 kilometers. That's quite a lot. Owners often have to control the level with a dipstick. If you miscalculate the moment, you can catch oil starvation, which is fraught with a decrease in the resource of the TSI engine, namely its piston group. Can this problem be solved? Unfortunately, this is an "incurable disease" of all TSI engines, so the owner can only regularly monitor the dipstick and carry a bottle of oil with him to top up.
Another problem that put an end to the reliability of the 1.4 TSI engine is the failure of the turbine. It is often "thrown" with oil, and by 80 thousand bearing play appears. The turbine is not able to pump air under the required pressure, which worsens the consumption dynamics and changes the behavior of the car. The cost of repairing a supercharger is about 60 thousand rubles, and there are several such turbines in the engine.
The next pitfall that calls into question the reliability of TSI engines is the gas distribution mechanism. They work from a chain that often stretches. The reason for this was excessively high loads. In recent years, the German manufacturer has begun to install a belt drive. According to the manufacturer, its strength has doubled. This improved the situation somewhat, but there are still many cars on the market with the old timing chain.
How long does a TSI engine last? According to the manufacturer, its resource is about three hundred thousand kilometers. However, in practice, these motors run 150-200 kilometers. What significantly aggravates the situation is the aluminum block. It is practically beyond repair. There are no usual wet sleeves that could be replaced, so in case of failure, it is easier to replace the TSI motor with a new one, which, by the way, is quite expensive.
Conclusion
So, we found out what the TSI engine is. The idea behind this motor is a good one. The Germans sought to make a powerful and productive engine, to get maximum efficiency from it. However, in pursuit of ideal performance, engineers did not take into account a lot of nuances that had already been corrected in the process of mass production of engines. Is it worth it to buy a car with such an engine? Experts give a negative answer, since the resource of these motors is really small. Also often there are problems with the chain drive. Despite the high performance and low fuel consumption, you should refrain from buying such a car. The owner may face unexpected repairs and quite a significant investment.
Surely many paid attention to cars with the "mysterious" inscription TSI.
Moreover, this abbreviation is typical for cars not only of the Volkswagen brand, but also of other brands that are part of the VAG (Volkswagen Audi Group) - Audi, Skoda, Seat ...
What does this inscription mean for the driver of such a car?
From this article you will learn:
TSI decoding
The abbreviation TSI stands for Twincharger Stratified Injection, which means a twin-charged engine with stratified or direct injection.
TSI engine has a more complex design than a conventional one. Despite the relatively small and good power reserve, the TSI engine is more economical and reliable.
The main distinguishing feature of such an engine is the presence of a two-stage boost - the first "stage" is a supercharger with a mechanical drive, and the second "stage" is a turbocharger.
The mechanical compressor operates up to 2.4 thousand revolutions. The intake damper for airflow opens fully when the rotational speed exceeds 3.5 thousand revolutions per minute. It is then that a strong air flow enters the turbocharger and maximum torque is reached.
There are TSI engines in which a button is installed to select winter driving. This mode eliminates wheel slip due to softer operation of the motor.
What advantages does
The efficiency of the TSI engine, combined with its solid power, deserves special attention. The power unit always provides the car with good dynamics, thanks to two superchargers at once, because in a wide speed range you can achieve the maximum torque value.
The use of a combination of a mechanical compressor and a turbine allows you to maintain traction as much as possible over a long period of revolutions. In this case, the mechanical compressor works independently at low speeds, and when working together - at medium speeds.
The next no less important advantage is the low level of CO2 emissions. It should be mentioned that "TSI" was nominated as the best "green" engine of the year.
Among other numerous advantages of the "TSI" line, it is worth highlighting their sufficient reliability and relatively high resource.
What are the disadvantages
Like any thing, the TSI engine has some disadvantages. It should not be forgotten that most modern turbocharged VW engines are very demanding on the quality of fuel and oil. The TSI engine was no exception; for normal operation, it needs only high-quality fuel and.
In addition, the TSI engine requires the owner to strictly comply with the rules for operating turbo engines prescribed in the vehicle documentation.
In addition, a TSI engine can cause some discomfort in winter. The reason is that the TSI engine of the family has a low heat transfer and practically does not warm up when idling in the cold season. In general, the optimal temperature regime of this engine is achieved only while driving after a certain period of time.
But there is another side of the coin, already positive - such an engine is not prone to overheating even in extreme heat in a long traffic jam. However, this feature can cause discomfort during the operation of a car with a TSI engine for short distances: an unheated engine means an unheated interior, since the traditional “stove”, which uses engine antifreeze in its work, will be ineffective.
But VW engineers have foreseen all these nuances by creating a dual-circuit cooling system with two thermostats: one circuit cools the hotter cylinder head, the second - the rest of the powertrain block.
To increase the service life of the TSI engine, the turbine is cooled by its own system, which includes an electrically driven water pump, which continues to drive the coolant for another 15 minutes after the engine has stopped.
Reading 4 min.
Engineers do not stop working on combining technical solutions in the engine for a minute. Each company chooses its own path, so fans appear in different companies in different numbers. Someone tritely makes a very large engine, someone designs their own turbines or combines several. And Volkswagen came up with TSI, what it is we will tell in this article.
Principle of operation
If we try to more or less literally translate Turbo Stratified Injection (TSI), we will get the following sentence: an engine that has turbocharging and direct injection. The difference between TSI and just a twin turbo lies in the fact that not two full-fledged turbines are used here, but a mechanical compressor and a turbocharger. The use of not sickly energy from the exhaust gases leaving the exhaust manifold allows you to rotate the turbine and increase the efficiency of the engine.
In the TSI system, the principle of minimization fully reveals itself, in which a smaller engine must produce much more power than its large counterpart.
The level of efficiency is also significantly improved, since a very large part of the exhaust is used to drive the turbocharger.
All the advantages of TSI can be seen in normal driving. The fact is that the crankshaft speed is usually always maintained within 1500-1750 rpm. And the torque at the same time is so high as if the shaft had spun up to 3500 rpm. This has a very positive effect on the economy of gasoline and on the power performance of the car. Generally speaking, the driver gets a wider range of power choices. A TSI engine usually has a gearbox (gearbox) with higher gear ratios, as this provides faster acceleration of the car and its dynamics. For a special direct injection system and for a better formation of the working mixture, special nozzles with 6 holes were invented. The electronic control unit has a special program in order to create ideal conditions for the combustion of gasoline in the engine cylinders.
Summing up, we can say that the main advantages are:
- Fuel economy.
- Power increase.
Intercooling
Another essential feature is the mandatory presence of an intercooler. The cooler is a higher quality radiator with circulating fluid to cool the air. Cold air reduces the amount of oxygen entering the turbine, due to this, the level of pressure created increases sharply, since cold air compresses better. As a result, due to the fact that the effect of turbo lag is minimal, and the combustion chamber is filled very well due to direct injection TSI, a significant improvement in vehicle dynamics is achieved. Also, the turbo-lag effect is almost completely absent.
Supercharging Features
This system has a very interesting air injection system. A special technology allows you to get the highest possible level of torque with a very small engine size: fuel injection is synchronized with the operation of the turbine or with the combined operation of the turbine and compressor. Due to this, more air enters the cylinders, and fuel is injected at a well-defined moment. As a result, a better combustion of the fuel mixture is obtained.
The combined operation of a mechanical compressor and a turbocharger gives significant advantages in general. At least the effect of the turbo-lag almost completely disappears. Since when the speed reaches the moment when the second compressor turns on, it has time to pick up the injection process and the motor does not fall into the pit. It is also worth noting that the mechanical compressor is powered by a belt drive from the crankshaft pulley, so it works immediately after starting the engine.
It is VW that today is the only manufacturer that has launched such engines with two turbines and direct injection into the series. This shows that such motors are very advanced power units of the car. Of course, the complexity in production affected the cost, however, it's worth it.
In the early 90s, when injection engines were just beginning to appear in the car markets, the public was baptized and ran away to hell, preferring the good old carburetors, with which not everyone was friends either. The same picture is observed in relation to the ten-year development of the Volkswagen AG concern, engines with the trivial abbreviation TSI. If diagnosticians and mechanics slowly began to deal with standard injection engines, then such a contraption as TSI causes a storm of rejection, although, in truth, it did not deserve it. What is a TSI engine and what do Volkswagen abbreviations mean in general, how much should we be afraid of them and why are they so scary, we will figure it out after a linguistic study.
TSI engines: what is it?
In the photo - the TSI engine, which was developed by Volkswagen
In order not to confuse motors and somehow distinguish them from each other at the user level without factory 17-digit indexes, many companies assign certain indexes to particularly distinguished or most typical motors. Moreover, some of them are fixed at the level of patents, as is the case with the TSI motor. This engine of a certain design type, developed by Volkswagen, is installed on almost all cars of the alliance - Volkswagen, Audi, Skoda, Seat.
Twincharged Stratified Injection is the original meaning of the abbreviation, which means "two supercharged engine with stratified injection." Sounds really scary. But that's not all. Later, this index began to be understood simply as a turbocharged engine with layered direct injection, Turbo Stratified Injection, without specifying the number of superchargers. Prior to this, the company used engines with the Fuel Stratified Injection, FSI index, which were without a turbine, but with direct injection. Audi confused everyone when they wrote on the TFSI engine. Later, these motors began to be installed on powerful versions of the Skoda Octavia, Seat Leon. These were 1.8 and 2.0 liter engines, but a year later, when a 160-horsepower engine with one compressor came out, Audi left the TFSI abbreviation, and Skoda and Seat, for unknown reasons, continued to label engines as TSI.
Video on how the TSI engine works
In 2006 there was another innovation. Volkswagen presented exactly the engine that we are going to talk about - a 1400 cc, 122-horsepower engine with two superchargers and direct injection. It would seem that the confusion is over. No matter how. When dual supercharging technology began to be installed on 1.8 liter engines, two absolutely identical engines appeared with the codes BYT, BZB, CDAA, CDAB, with a capacity of 160 horses and a CDAB engine, which had 152 horsepower with the same design solution and absolutely the same or iron. It turned out that for some markets the company developed a lower power motor in order to fit into environmental standards and meet acceptable state fees. (Meaning RF). In a word, all these indices: FSI, TFSI, TSI, are officially registered with the Volkswagen AG alliance, and what distinguishes the TSI engine in technical terms is a different story.
A separate story about two supercharging and TSI direct injection
It’s worth starting with what the TSI engine brought to the automotive world that is new and beautiful. We emphasize that we are talking about a 1.4-liter 122-horsepower engine. This motor saved the driver from one important drawback of all turbocharged units - turbo lag. The fact is that with such a small volume, it is almost impossible to maintain torque in a wide range of revolutions. The turbine starts to work only with an increase in the speed, more than 3000 rpm, before this threshold the engine actually sleeps. Volkswagen engineers did it simply - they installed another supercharger, but not a turbo, but a mechanical one, like Roots. The mechanical compressor pumps air directly into the combustion chamber until the turbine kicks in. After that, the wastegate cuts off the mechanical supercharger, leaving the engine under the care of the turbo.
The abbreviation TSI in translation is read as "engine with two supercharging and layered injection"
As soon as the engine speed drops, the control unit immediately switches the wastegate to supercharger mode, which ensures that maximum torque is maintained over a wide speed range. And this is not the only feature of the TSI engine. Another innovation was the use of direct injection nozzles with 6 holes. The six-jet nozzle supplies fuel to the combustion chamber at a pressure of about 150 bar, ensuring perfect filling, thereby reducing fuel consumption. The performance of the engine is really phenomenal, if we talk about the completed serial unit, and they are quite easy to track. according to the modifications of this engine, of which there are several:
- The most modest in the family is 1.2 TSI. This is a cast-iron cylinder block, a stamped crankshaft and one turbine. Yes, this is TSI, but not in the sense of tween, in the sense of turbo. The turbine pumps out about 1.6 bar, and the engine can produce from 86 to 90 horsepower, depending on the market. It is installed on the Audi A1 and A2, all small Volkswagens, Skoda Roomster, Yeti, Fabia and Rapid, budget Volkswagens and Seat Ibiza, Altea and Leon.
- The same 1.4 TSI. Optimum ratio of power, torque, efficiency and volume. The company says that this is the best turbo engine money can buy. Perhaps, but its price is about $ 1,000 when compared with a simple MPI engine on the same Golfs or Jetts. It's worth it, because on the Fabia RS this motor shows no less than 180 horses. The charged Polo GTI, Ibiza Cupra have the same parameters, and in standard versions, the engines produce 105, 122 and 150 forces, depending on whether there is one boost in the car or two.
- Another very. This time around, the most common one in the US, the 1.8-litre TSI, makes the same 180 horsepower as the little Fabia. It completely replaced the 2.5-liter engine according to its characteristics. The alliance also produces 2.0 TSI engines for large crossovers and hybrid versions of the Tuareg. These engines can develop from 200 to 230 forces, and now V-shaped three-liter sixes with a capacity of 333 forces are being actively introduced.
Why be afraid of TSI?
Because this engine is designed to run only on good fuels and only on excellent oils. Subject to these conditions, the motor will work flawlessly, and the plant guarantees it a resource of 300 thousand km. Reviews also report problems with the injection system at the first acquaintance with our gasoline. Well, nothing can be done about it, but the problems with the chain, which the same reviews say, can be avoided. The chain can slip on the gear, then the phase shift occurs, and if it is strong enough, this can lead to bending of the valves. But again, this is due to the human factor.
You should not start modern cars from a tow. If it does not start, you need to look for the cause or contact specialists and carry out qualified repairs. They also talk about increased oil consumption in these engines, but the factory flow rate is a liter per 1000 km, however, it depends on which oil to pour. The reliability of this engine is beyond doubt, and if you protect it from bad oil and properly filter gasoline, there will be no problems with it throughout its entire service life.
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Cars with the TSI label have a special heart under the hood. This is a motor in which the designers of Volkswagen have applied the most modern technologies and research, implementing them on serial machines to change the characteristics of this type of motor.
What does the definition of a TSI engine mean?
Recently, a new TSI marking has appeared on many cars. This abbreviation refers to a new type of automotive engine with an improved design. The abbreviation TSI, which can be deciphered as Turbo Stratified Injection, when translated into Russian, it can be expressed approximately as "Turbo Layered Fuel Injection". Using this principle of fuel supply in TSI engines, the manufacturer managed to achieve high quality of work during the operation of engines.
The main feature of TSI engines is the duplication of pressurization systems with a mechanical compressor and a turbine supercharger. This design allows for all modes of motor robots to achieve high performance and significant fuel savings due to the possibility of varying fuel injection modes, due to this, it is possible to achieve high efficiency.
In such engines there are such basic modes of operation:
Compressor boost range as required.
At engine speeds up to 3500, if necessary, a compressor is connected. All this is necessary when the motor is constantly running in this mode, and then follows a strong acceleration. The inertia of the turbocharger leads to a delay in the creation of the necessary pressure (the so-called "turbo pit"). Therefore, a compressor is connected here, which in the shortest possible time creates the necessary inlet pressure.
Compressor constant boost range.
Starting from idle and up to 2400 engine revolutions, the mechanical compressor is constantly on. With this difference in speed, the boost pressure in the compressor is regulated by the control unit for the damper installed in the intake manifold.
Turbo boost range only.
When the engine speed is over 3500, then the turbine supercharger alone can create the necessary pressure. In this case, the air boost pressure is controlled by the boost pressure limiting solenoid valve.
In addition to the dual boost system, a feature of the TSI engine is the specificity of the engine cooling system. It has two cooling circuits: a cylinder head with a turbine and a cylinder block with an intercooler.
The main components of the engine, the improvement has occurred
The task of increasing engine power without a significant increase in its volume and weight, maintaining fuel efficiency, the design department of the Volkswagen concern was able to implement by making non-standard solutions.
Structurally, the TSI engine has features in comparison with other engines, namely double injection - a mechanical compressor and a turbocharger. The TSI engine was based on a four-cylinder power unit, which was equipped with a sequential fuel injection system, a mechanical supercharger of the Roots type, and a turbocharger was installed.
The division of the cooling system into two (one cools the engine head and exhaust manifold, and the other - the cylinder block and liquid intercooler) allows for efficient cooling of the forced air.
When one of the most important priorities for the car was determined - with smaller volumes, the highest power density - design thought came to the idea of supercharging. Why does a motor need two boost systems?
Each of the systems separately has its drawbacks. So, the turbo does not work at low speeds. For its normal operation, the engine must be spun up to 3000 rpm, that is, keep high speeds all the time in order to avoid failures (the so-called turbo pits). At high speeds, the efficiency of the mechanical compressor drops, but at low speeds it allows the motor to work at full efficiency. In transient conditions, both systems duplicate each other, which gives a positive result, making it possible to remove the maximum torque from the engine. The first were mechanical (forced) superchargers, which are driven by the engine crankshaft.
But the supercharger, driven by a turbine, which is affected by exhaust gases, has received more use in the automotive industry. When the load and the number of revolutions change, the engine ECU calculates how much air is needed to create the desired torque, and enters the cylinders. In this case, it determines whether the turbine blower itself is operating or whether a mechanical compressor should be added to the operation.
TSI engines have several operating ranges:
Naturally aspirated at minimum load.
In naturally aspirated mode, the control flap is fully open. The air that enters the engine enters through the turbocharger flap, which is controlled by the regulating control unit. At this time, the turbine supercharger is already working under the influence of exhaust gases. Their energy is so insignificant that a minimum boost pressure is created. In this case, the throttle valve opens at the request of the driver (by pressing the gas pedal), and a vacuum is created at the inlet to the cylinders.
Mechanical compressor and turbine blower for high loads and speeds up to 2400 rpm.
When operating in this range, the air quantity damper is closed or slightly ajar to regulate intake manifold pressure. In this case, the compressor is put into operation through a magnetic coupling and is driven by a V-ribbed belt drive (it sucks in air and compresses it). Compressed air is forced by the compressor to the turbine supercharger. This further compresses the air. The boost pressure of the compressor is measured in the intake manifold by a pressure sensor and is changed by the control flap control unit. The total boost pressure is measured by the boost pressure sensor with the throttle valve fully open. At the inlet to the cylinders, a pressure of up to 2.5 bar is created.
The operation of the turbine supercharger and mechanical compressor at high loads and speeds from 2400 to 3500 rpm.
When the engine is running in this mode (for example, at a constant speed), the boost pressure is created only by the turbine supercharger. When accelerating, the turbine would work with a delay and would not be able to create the necessary air pressure in time (turbo pit may occur). But to exclude this, the engine control unit connects the compressor through the electromagnetic clutch. This changes the position of the regulating flap, creating the corresponding boost pressure. So the mechanical compressor helps the turbine supercharger in creating the necessary air pressure to run the engine.
Work with a turbine supercharger.
When the engine speed is over 3500 rpm, the turbine itself can create the necessary air pressure at any point in the load. In this situation, the damper that regulates the air supply is fully open and fresh air flows directly to the turbocharger. Under these conditions, the pressure of the exhaust gases will be enough for the turbine supercharger to create the pressure necessary for boosting. It is, however, completely open. The inlet is pressurized up to 2.0 bar. The pressure generated by the turbocharger is measured by the boost pressure sensor and is controlled by the boost pressure control valve.
Dual supercharging is the simultaneous use of a mechanical compressor + turbine supercharger. The compressor is a mechanical type supercharger, which is connected through an electromagnetic clutch.
Advantages of a mechanical compressor:
- fast injection of the required pressure into the intake manifold;
Creation of a greater torque at low engine speeds;
Its connection occurs on demand;
It does not require additional lubrication and cooling.
Disadvantages of a mechanical compressor:
- power take-off from the motor,
The boost pressure is created depending on the speed of the crankshaft and then adjusted, while again losing part of the work done.
The turbocharger is constantly driven by the exhaust gases.
The advantages of this unit: high efficiency due to the use of energy from exhaust gases. Disadvantages of a turbine supercharger:with a small engine displacement, the generated amount of exhaust gases is not enough to create boost pressure at low engine speeds and create a high turbine torque, high temperature load.
Using a combined supercharging system, that is, combining classic turbocharging and mechanical, the creators of the TSI engine achieved maximum power performance in all engine operating modes.
Cooling system
The classic cooling system is single-circuit. To increase the efficiency of the TSI engine robots, the designers divided the engine cooling system into two circuits to improve the quality of the engine and its systems.
The cooling system was divided into two modules: one circuit serves the exhaust manifold and engine head (hot), the other (cold) cools the cylinder block and the charge air in the intercooler. These motors have a water intercooler, which replaced the air one. Due to this, the air that is injected into the cylinders has a higher pressure indicator. The result of this modernization is the uniform filling of the combustion chambers with a fuel-air mixture and an increase in vehicle dynamics. So, already at a speed of 1000 - 1500 we get a torque of about the declared figure of 210 Nm.
A dual-circuit cooling system is a scheme in which the contours of the cylinder block and the block head are separated. In the cylinder head, coolant moves from the exhaust manifold to the intake manifold. Thus, a uniform temperature regime is maintained. This design scheme is called transverse cooling. The following changes have also been made to the cooling system:
- the thermostat is made with two steps;
To cool the turbine when the engine is stopped, a recirculation pump for coolant is installed;
The turbine supercharger has forced cooling.
Approximately one third of the engine coolant goes to the cylinder block, and the remaining 2/3 goes to the cylinder head to the combustion chambers. Advantages of a dual circuit cooling system:
- the cylinder block warms up more quickly, the temperature rises to 95 ° due to what remains in the block;
Reduced friction in the crank mechanism due to increased temperature in the cylinder block;
Improving the cooling of the combustion chambers due to a temperature decrease of about 80 ° in the head of the block; thus, improved filling is achieved while reducing the possibility of detonation.
A feature of the cooling system is the coolant distributor housing with a thermostat, which has two stages. With such a volume of coolant at high engine speeds, increased pressure occurs in the cooling system. Even under these conditions, the two-stage thermostat opens at the set time according to the desired temperature.
When a thermostat with one stage is installed, it would be necessary to overcome the high pressure and move the large thermostat plate. And therefore, due to counter forces, the thermostat could open only at a high temperature.
In a two-stage thermostat, when the opening temperature is reached, the small plate will open first. Due to the small area, the forces that act on the plate are smaller, and the thermostat opens strictly in accordance with the temperature. After passing a certain course, the small plate begins to pull the large one, completely opening the large coolant passage.
When the TSI engine warms up, this system makes it possible to maintain the operating temperature in the engine in accordance with the specified parameters and reduce fuel consumption and harmful emissions. To improve warm-up and reduce the possibility of overheating, it is necessary to intensively cool the hot cylinder head. At the same time, the amount of coolant in the block head is twice the amount of liquid in the cylinder block, and the thermostats open, respectively, at a temperature of 95 ° and 80 °.
The turbine is protected from overheating by an additional electrically driven auxiliary water pump, which makes the liquid circulate in a separate circuit after the engine is stopped for up to 1/4 hour. With this principle of operation, the service life of the turbine supercharger of the TSI engine is significantly increased.
Fuel is supplied through a variable fuel injection system. The advantage of this system is that the electric fuel pump, like the high pressure fuel pump, delivers as much gasoline as the engine needs. Thus, the electrical and mechanical power of the fuel pumps is reduced and fuel is saved.
For direct fuel injection, the injectors are installed directly into the cylinder head. Under high pressure, fuel is injected through them into the cylinders. The main task for injectors:they are obliged to spray and purposefully supply gasoline to the cylinders in a minimum period of time.
When starting a cold engine, the TSI engine uses dual injection. This is done in order to warm up the catalyst when starting the engine. The first time during the suction stroke, and the second - when the engine crankshaft during rotation did not reach about 50 ° to the top dead center. When the engine is running under normal conditions, fuel is delivered during the intake stroke, distributing it evenly in the combustion chamber. The injectors installed on the TSI have 6 channels for fuel injection.
Thus, the direction of individual jets does not allow moistening of the elements of the combustion chamber, providing a better distribution of the fuel-air mixture. In this case, the maximum value of the fuel injection pressure reaches 150 bar. This makes it possible to guarantee high-quality preparation of the fuel mixture and reliable atomization. In this case, there will be enough fuel even at maximum loads.
On TSI engines, fuel enters directly into the cylinders, and not into the intake manifold, the mixture formation occurs “in layers”, and at the same time, high-quality combustion occurs with high efficiency. All these factors make it possible to slightly increase power and reduce fuel consumption.
It should be noted that the efforts of engineers to reduce the weight of the cylinder block have yielded results. The 1.2 liter TSI engine block is cast in aluminium. When compared with the engine block, which is made of gray cast iron (such cylinder blocks are used in the TSI engine with a volume of 1.4 liters), the new cylinder block reduced the weight by 14.5 kg and amounted to 19.5 kg. The design of the new TSI 1.2l open plate engine block is identical to that of the 1.4l TSI engine. The peculiarity of this scheme is that the inner wall of the cylinder block with liners does not have jumpers in the area where the cylinder block contacts the block head.
This design has its advantages:
- it reduces the possibility of air bubbles, in a system with dual-circuit cooling, they can create a problem for removing air from the engine cooling system.
By assembling the cylinder block and cylinder head into a single unit, cylinder deformations are reduced and form a more uniform structure, compared to a closed plate and web design.
All this leads to a reduction in oil consumption, because the piston rings are better able to compensate for deformations. Four sleeves are installed in the cylinder block, cast from gray cast iron with a profiled outer surface. This profile improves the connection between the cylinder block and the cylinder liners, thus reducing the deformation of the cylinder block. This technological solution made it possible to reduce the uneven distribution of heat that appears between the sleeves and the aluminum block.
Advantages of the TSI engine
The advantages of motors with the abbreviation TSI include:
1. Design efficiency (minimum fuel consumption results in maximum torque over a wider rev range).
2. Due to the reduction in engine weight and displacement, friction losses are significantly reduced.
3. The fuel consumed by the engine is saved.
4. With improved fuel combustion characteristics, the amount of harmful emissions into the environment is reduced.
TSI are engines with direct fuel injection systems and twin turbocharging (contains a compressor and a turbine). Such engines are more complicated than conventional turbocharged ones, but they are more reliable, more powerful and more economical. They have virtually no flaws.
A feature of these motors is a two-stage boost, which consists of a turbine supercharger and a mechanically driven compressor. The TSI engine is packed with state-of-the-art technology, but requires proper maintenance to keep it running reliably. Therefore, it is necessary to use high-quality consumables and fluids, and carry out maintenance on time. The components and assemblies included in the TSI engine, and timely maintenance will more than pay off due to gasoline savings.
In order to reduce noise, this engine has an additional housing, which is made of sound-absorbing materials.
Engine use in our country
This engine is designed to run only on good fuel and only on excellent oils, we need to look for good fuel.
To disadvantages of TSI engines that will be operated in our conditions include:
- high quality requirements for fuels and lubricants - gasoline, oil, etc.;
Maintenance, which must be carried out regularly and only in authorized service centers;
These engines are sensitive to low ambient temperatures, which makes it difficult to operate in winter.
But drivers who have experience in operating TSI engines notice that warming up at idle is not necessary - you can start driving without warming up with a cold engine. TSI engines with direct injection systems in the cylinders and twin turbocharging are engines more complex than conventional ones, but they are more reliable, more powerful and more economical.
One of the biggest disadvantages is that in winter the engine does not warm up well when idling. When driving, the engine reaches the set temperature for a long time. Therefore, for drivers who drive close distances, this will create a problem (you will have to drive with an unheated “stove” and endure cold air blowing from the heater in frosty weather). The TSI engine does not create other problems.
It should also be noted increased mechanical and thermal loads, double boost. All this forces manufacturers to constantly work on changing the design, strengthening some of the engine components and assemblies. This complicates the production and maintenance of such units.