MPI engine - means an injection engine that uses a multi-point fuel injection system. She gave the name to this power unit - Multi Point Injection. In other words, each has its own injector (nozzle). This scheme was developed and implemented by the Volkswagen concern. Historically, for the Wolfsburg carmakers, the MPI system was the first fuel injection system. Now this type of unit no longer meets the modern economic and environmental requirements for car engines. Until recently, it could be said that this type of engine was discontinued and the last model of the concern's car, where it was used, was the second series. But unexpectedly, the MPI engine was revived, and it again became in demand! Let's keep the intrigue and tell about it at the end of the article. And now let's say that the most prominent representatives of this family of engines in recent years have been power units 1.4 (80 hp) and 1.6 liters (105 hp).
Feature of the MPI engine in a multipoint injection system
MPI engine in detail
We have already said about the first and main distinguishing feature of these power units - this is the multi-point fuel supply. But those who are more familiar with car motors can say that, for example, TSI engines also have multipoint injection. Therefore, we turn to the second difference - the lack of pressurization. That is, there are no turbochargers for pumping the fuel mixture into the cylinders. Conventional, which delivers fuel at a trivial pressure of 3 atmospheres to a special intake manifold, where it is then mixed with air and sucked through the intake valve into the cylinder. As you can see, in this moment it is very similar to the operation of a carburetor motor. There is no direct injection of fuel into the cylinder, as in TSI or GDi-schemes, there is no trace.
The third distinctive feature is the presence of a water cooling system for the fuel mixture. This is due to the fact that a rather high temperature develops in the area of \u200b\u200bthe cylinder head, and the fuel enters at a relatively low pressure. Therefore, it can simply boil and form gas-air locks.
Advantages and disadvantages of MPI engines
Benefits
First, about the merits, and so significant that even now many people are happy to operate cars with such engines. Especially in our country, where the requirements for environmental friendliness are not as strict as in Europe (which is a vivid example of the presence of mercilessly smoking "kopecks" and other domestic and foreign pre-antique movable property). And the cost of fuel is still not as biting as that of Europeans.
- Simplicity of design. Of course, this is not a carburetor, but neither is the TSI with its high pressure pump and turbocharger. And the simplicity of the design automatically means the availability of the unit itself and its possible repair at the price.
- Lower requirements for. The MPI engine does quite well on 92 petrol. And try to fill it, for example, in a modern Volkswagen Passat. Such a certain omnivorousness, by the way, somewhat neutralizes one of the disadvantages of such motors (about them a little below) - lower efficiency.
- Less tendency to overheat.
MPI engines have no special requirements for fuel quality
Another advantage, though not directly related fromthe considered scheme of the injection power unit is the presence of rubber mounts under the engine. This significantly reduces noise and vibration when driving.
disadvantages
- Less cost-effective. Nothing to do about. Multi-point injection is good, of course, but supercharging with direct fuel injection into the cylinder (like TSI systems) is better.
- Weak torque and lack of power. Nevertheless, the possibilities of a circuit that provides for the connection of air with gasoline in the manifold, and not in the cylinder, are somewhat limited. So for those who like driving and racing at traffic lights, the MPI engine will not work. Too sluggish.
And yet, if we summarize the advantages and disadvantages, the final result makes these power units quite competitive, especially for our domestic realities. It is no coincidence that for the Russian the Germans abandoned the turbocharged 1.2-liter TSI engine, preferring the proven and unpretentious 1.6-liter MPI horse.
The Russian version of the Skoda Yeti has an MPI engine
Now, we think it will be clear what an MPI engine is. If you have any questions about this article, ask. We will definitely answer.
The forthcoming publication is intended for experienced drivers who change their vehicles. Today, an engine labeled MPI is considered a kind of rarity, supplanted by more advanced innovative developments. And at one time such a power unit was a novelty of advanced technologies.
The information provided will help you better understand the device of this motor, weigh its disadvantages and evaluate its advantages. Also in this article you can find a detailed description of the principle of operation of the complex mechanism with the MPI index.
What was good about the MPI engine, memories of achievements in the field of automotive industry
Some confirmation of the well-known statement that nothing lasts forever in our ghostly world is the gradually disappearing popularity of the power unit with the MPI marking. At one time, it was considered a very successful replacement for carburetor engines, a definite innovation in the modern automotive industry, an advanced stage in its development.
Today, most motorists look at each other in bewilderment at the mention of the abbreviation MPI, since contemporaries are more familiar with the TSI, FSI engines or the BSE that appeared in 2005. It should be noted that the latest model of the engine is characterized by excellent portability of domestic fuel, whose quality leaves much to be desired.
In the line of injection engines, the unit in question occupies a worthy place, characterized by extreme practicality, reliability and reliability. At the time of its launch into production, it was considered the forefront of the domestic automotive industry.
What did the drivers with considerable experience remember the MPI injection engine. What are the features of its principle of operation, what are the indisputable advantages and annoying flaws. Further information will answer the questions of curious motorists.
The principle of operation of the MPI power plant
First, you need to explain to uninformed readers that the abbreviation MPI stands for an internal combustion engine, each cylinder of which corresponds to a separate injector. The name MPI DOHC is much more common. Here the second part of the name indicates two camshafts with four valves.
The principle of operation of the main mechanisms that make the MPI engine function is quite simple. Nevertheless, it deserves a separate consideration.
Fuel is supplied simultaneously from several points. As mentioned earlier, each cylinder has its own injector and a dedicated exhaust port for fuel delivery. Multi-point fuel supply is also characteristic of the TSI engine, but it differs in the presence of pressurization, which is absent in the engine in question.
A special intake manifold is an intermediate link, where fuel is supplied under a pressure of three atmospheres by a special pump. A mixture of gasoline with air is formed in it, after which it enters the cylinders through the intake valve. The whole process is carried out at elevated pressure.
Briefly, the operation of the engine can be described in three stages:
- First, the fuel from the gas tank is pumped to the injector;
- After receiving a certain signal from the electronic control unit, the injector directs the fuel into a special channel;
- In this direction, the fuel mixture is delivered to the combustion chamber.
Some similarity in the principle of operation with the carburetor unit is leveled by the presence of a liquid cooling system. This need is due to excessive overheating of the space at the cylinder head.
A strong rise in temperature can cause fuel that is there under low pressure to boil. The gases emitted during this process can form undesirable gas-air locks.
Another distinguishing feature of the MPI engine is the presence of a specific control mechanism for the hydraulic drive, consisting of a clutch equipped with a grease nipple, and a special system that sets certain limits for trims.
It is usually represented by rubber supports, a distinctive feature of which is the ability to independently adapt to the operating mode of the power unit. Their main purpose is considered to be noise and vibration reduction during engine operation.
The design of the MPI engine also includes eight valves, located in pairs on each of the four cylinders. An important part of such an engine is the camshaft, which is considered an essential part of the system.
Advantages and disadvantages of MPI motors
First of all, it should be noted the undeniable advantages of the design of the unit in question, namely:
- The presence in the device of the power plant of the function of advancing the ignition process helps to increase the sensitivity of the throttle located on the gas pedal. This significantly expands the possibilities of driving a car;
- Water cooling of the gasoline-air mixture allows maintaining an acceptable temperature in the engine, protecting against the formation of gas-air jams;
- The advanced hydraulic drive control system makes it possible to significantly reduce the noise and vibration produced by a functioning motor.
Among other advantages of power units with MPI marking, the following can be noted:
- Unpretentiousness to the quality of fuel. For domestic motorists, the possibility of using inexpensive AI-92 gasoline is especially attractive, which translates into significant savings at refueling;
- Reliability and strength of the structure. The manufacturer declared a minimum motor resource of 300 thousand km. However, trouble-free operation of the engine is impossible without periodic replacement of lubricants and filters;
- The extreme simplicity of the power unit is reflected in the cost and laboriousness of the repair.
You cannot do without a fly in the ointment, which somewhat belittles the listed advantages of the MPI motor. In our case, a significant flaw in such engines is the loss of power arising from the limited intake system. However, although the units under consideration lose dynamism due to the presence of eight valves in the timing mechanism, a measured calm ride with their help is ensured.
Conclusion
Having considered in detail all the advantages of MPI engines, and carefully weighing the disadvantages, it becomes unclear why the manufacturer abandoned their widespread use. If earlier almost all Volksvagen car models were equipped with such motors, today they are installed only on the second generation Skoda Octavia.
The design of power units is considered outdated and is gradually being phased out, being replaced by high-tech innovations.
"Interested in how TSI and MPI motors differ?"
To understand the difference between TSI and MPI engines, it is necessary to decipher the abbreviations by which they stand. In particular, MPI stands for Multi Point Injection, which means "multipoint injection". In the Russian-language automotive literature, the term "multipoint" is usually replaced by the word "distributed", which is why, in practice, MPI engines are often called engines with distributed fuel injection.
The main design feature of distributed injection is that gasoline is injected into the intake manifold by nozzles installed opposite the intake valves, and enters the cylinders mixed with air when these valves are opened.
A different principle of fuel delivery and mixture formation is implemented in TSI engines, where the abbreviation TSI, registered by the Volkswagen concern, originally meant Twincharged Stratified Injection, which can be translated as "double supercharging stratified injection".
Such injection can only be achieved if fuel is supplied directly into each individual cylinder of the engine. Therefore, more often such power systems are called direct or direct fuel injection. If in MPI engines, the formation of a combustible mixture begins in the intake manifold and ends in the cylinder by the time the spark plug is applied, then in TSI engines everything happens inside the cylinders.
It is worth focusing on the fact that MPI, unlike TSI, is not a patented name, but a common designation for gasoline engines with distributed fuel injection, which is used by a wide variety of car brands, and not just those belonging to the Volkswagen concern.
Later, when TSI engines began to be equipped with not only "double", but also "single" supercharging, Volkswagen suggested another interpretation for the acronym - Turbo Stratified Injection. The presence of the term Turbo indicates that the TSI engines are turbocharged. If the boost is taken away from Volkswagen engines with direct petrol injection, then these will not be TSI engines, but FSI, where the letter F is an abbreviation for Fuel, fuel.
We could put an end here, because we talked about the fundamental differences between TSI and MPI, but it is unlikely that the reader who asked the question was driven only by purely theoretical curiosity. It is possible that the question has a practical rationale - which of the motors to prefer?
Direct injection and turbocharging are a serious complication and increase in engine cost, however, engines with a similar design have higher power and, at the same time, better economy and environmental characteristics compared to engines with distributed fuel injection of the same displacement.
The evolution of the 1984 cc gasoline engine can be traced. cm, which was equipped with VW Passat. The eight-valve 2.0 MPI developed 115 hp, accelerated the car from standstill to 100 km / h in 11.5 seconds, allowed to drive at a maximum speed of 194 km / h, consumed 6.6 / 8.5 / 12 l / 100 km at 90/120 km / h / city. Similar characteristics to the 16-valve 2.0 FSI: 150 hp; 9.4 seconds; 213 km / h; 6.6 / 8.4 / 11.4 l / 100 km. And the same with the 16-valve 2.0 TSI: 200 hp; 7.8 seconds; 232 km / h; 6.4 / 8.2 / 11.3 l / 100 km. Undoubtedly, multivalve gas distribution also influenced the performance of engines, but direct injection and turbocharging is the main direction of the further development of gasoline engines. The future belongs to such motors.
Another thing is that TSI engines are more capricious, demanding and delicate, which is why they often suffer from problems than motors with distributed gasoline injection that are less fastidious and more resistant to abnormal handling, and troubleshooting in TSI is more expensive than in MPI. If we put power and fuel consumption on one side of the scale, and on the other side - the reliability and cost of solving emerging problems, then for our operating conditions it seems preferable to choose a version with MPI, even if these engines are from the point of view of technical progress and the last century.
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The MPI engine is slowly becoming a thing of the past. Not everyone knows what it is, mainly those who have changed many cars in their lives and have been driving for several years. Probably also those who are interested in technology in general and the automotive industry in particular. But at one time such a motor was a huge step forward: it was he who replaced the carburetor one.
Among Volkswagen engines, this is the oldest development from those that were still in use until recently. True, the MPI engine has been installed in recent years mainly on the Skoda model. The last swallows were the second series Skoda Octavia; on the third, more appropriate FSI or TSI requirements were already installed. And yet it is still believed that MPI is the most reliable, practical and reliable among all injection engines.
MPI engine: what it is is quite simple to explain. Indeed, it is based on a universally used injector, with only some features and limitations.
Device
The abbreviation stands for Multi Point Injection, that is, multipoint injection. The engine is a gasoline unit, by definition not turbocharged, in which point injection is distributed over the cylinders. Each cylinder comes with one injector that delivers pressurized fuel through a dedicated intake port.
The design does not provide for a fuel rail, as is the injection injection on TSI series engines. There is also no direct injection directly into the cylinders, as is done in the TFSI or FSI engines. Due to the design features, the MPI motor had an ignition timing function, due to which the throttle was extremely sensitive to the gas pedal.
The rest of the mechanisms are supplied with a water cooling system. In the performance of the Volkswagen company, it is a MerCruiser, which stabilizes the operation of the engine thanks to a developed system for removing gas and air jams.
The Germans supply the MPI engine with a well thought out hydraulic control system, a clutch with an integrated grease nipple. And the engineering solution for differentiating the engine can be considered particularly successful: the design is based on rubber mounts, which automatically adjust to the rhythm and speed of movement, engine speed and unevenness of the coating.
Due to all this, motor vibration and noise from it are noticeably reduced. The engine itself is for 4 cylinders and 8 valves (at the rate of 2 per cylinder). In terms of power, MPI engines were produced at 1.4 liters with 80 horses and 1.6 - from 105.
Advantages
The main advantage of this engine is its simplicity. Due to this, it is easily repaired and is inexpensive to maintain. In addition, 92 gasoline is quite suitable for it (and not only from alternative manufacturers, but also for the original models of Volkswagen). The construction is as strong as possible. If we deal with German cars with such an engine, then the manufacturer guarantees a maintenance-free run of 300,000 - if you are not lazy to change filters and oil on time.
disadvantages
They are due precisely to the design features of the engine. Namely: fuel is combined with air in channels, and not directly in the cylinders. Therefore, the capabilities of the intake system are somewhat limited. As a result, we have a lack of power and. As a result - no special dynamics, no hot drive, no sporty throttle response. These qualities are enhanced by the number of valves - 8 pieces for modern cars is no longer enough. It can be said that this is a family and leisurely car.
MPI and modernity
That is why, probably, the MPI engine is becoming a thing of the past. The world appreciated what it is, decided that this was not enough for it, and began to invent new, more powerful and modern motors. However, there are also unexpected comebacks in the global automotive industry. So the Skoda company for the Russian version of its Yeti model, declared as an SUV for family use, deliberately abandoned the 1.2 turbocharged engine in 2014 in favor of 1.6 mpi (110 hp). (read
One of the very popular engines, the installation of which is carried out on cars of the Volkswagen manufacturer (currently, most of them are equipped with SKODA) is the MPI engine. Of course, it should be noted that this engine model is the oldest of the entire available line of Volkswagen power units, but we must give it its due, since MPI is the most practical and reliable of the entire line of power units, we read about the TSI engine.
Principle of operation.
This type of engine (translated as multipoint injection) is a non-turbocharged engine that runs on gasoline and uses multipoint distributed fuel injection through an injector during its operation. MPI does not have a fuel rail, like many other types of engine, also does not have fuel injection into the cylinders themselves, only one injector is used for each cylinder separately.
This power unit has its own individual fuel injection structure. It can be roughly expressed as follows: there is one injector for one separate cylinder, the fuel supply is carried out through a specially made exhaust channel.
Also, MPI is endowed with the function of advancing the ignition process, due to which an increased indicator of the sensitivity of the gas pedal is provided. The structure of this engine is unthinkable without cooling the fuel mixture (MerCruiser) with water, thereby achieving the required temperature of the fuel mixture. This helps many times to increase the stability indicators during engine operation by getting rid of gas (air) locks.
This type of power unit is also equipped with a new system that independently controls the hydraulic drive. There is a clutch with a grease nipple, a system that allows you to limit trimming and has a memory (it is based on rubber mounts that independently adjust to the operating mode of the motor, thereby significantly reducing vibration and noise during operation).
The engine has an eight-valve system (two valves per cylinder) and a camshaft. The most striking representatives in this engine family are considered to be the MPI 1.6 engine (105 hp) and the MPI 1.4 liter engine (80 hp).
Dignity.
The engine is quite unpretentious and can run well on 92nd gasoline. As stated by its manufacturer, the design of the MPI engine is very durable, and its minimum mileage without any repair will be three hundred thousand kilometers, of course, provided that filters and oil are replaced in a timely manner.
And due to the uncomplicated MPI device, it is easy and cheap to repair.
Disadvantages.
Due to the fact that the process of fuel mixing takes place in special exhaust channels (before it enters the cylinders), such engines have a limited intake system capability. And this, in turn, affects the indicators of torque and power. They also cannot be called cocky and “dynamic”. The presence of an 8-valve timing system also indicates a significant loss in power. In general, they are designed for slow, unhurried driving.
Due to its relatively old structure, MPI is slowly being phased out of mass production. The most recent car models equipped with these powertrains were the second generation Scoda Octavia. At the same time, the third generation has already been equipped with more advanced and modern motors.
