What is an MPI engine? We tell, explain and explain What does mpi mean on Skoda Octavia

Period of heightened interest in gasoline engines MPI (abbreviation stands for Multi Point Injection) came at the end of the last and the beginning of this century. The demand for cars with such installations is due to the non-standard fuel injection scheme, which is built on a multi-point principle.

Each cylinder of such an installation has its own injector, as a result of which the fuel mixture is distributed as evenly as possible over all cylinders. The embodiment of the idea of an automobile engine with multipoint injection was engaged in Volkswagen, which greatly contributed to the emergence in the face of MPI of an effective alternative to carburetor engines. Let's try to take a closer look at what an MPI engine is and evaluate its competitive sides.

How modern is Multi Point Injection

A few years ago, it seemed that there were no future MPI engines, and it was even possible to believe that the production of such engines was completely suspended. This is not surprising, because the rapid development of automotive technology very soon makes one forget about what was considered a flagship or a benchmark of quality yesterday. Something similar is happening with MPI units, which many industry experts seem to be outdated and inconsistent with today's environmental and economic views.

If for the European market such conclusions are true, then for the Russian market it is only partly, because many domestic motorists have not yet discovered the real potential of these units. Fortunately, far-sighted manufacturers do not let the technology "die" and are still actively introducing it, for example, in the case of the second Škoda Octavia series, Volkswagen polo, Volkswagen golf 7, Škoda Yeti for Russian roads, etc. The most memorable representatives with MPI in recent years are 1.4 and 1.6 liter engines.

MPI - the engine as it is

Along with the multi-point injection system, there is another significant detail - the complete absence of a turbocharger. In the presence of a typical gasoline pump that supplies fuel to the intake manifold under pressure of three atmospheres for subsequent mixture formation and the receipt of the finished composition into the cylinder through the intake valve. As you can see, the diagram is similar to what happens in engines with a carburetor, with the difference that each cylinder is equipped with a separate injector.

Multi Point Injection The engine is equipped with a water cooling circuit for the fuel mixture, which is somewhat unusual. Such a move is dictated by the fact that in the area of the cylinder head the temperature is quite high, while the pressure of the incoming fuel is relatively low, which is why there is a high probability of boiling and, as a result, the occurrence of a gas-air lock.

Pros and Benefits of MPI

Compatriots who have already been lucky enough to get to know MPI engines better, before switching to a car with a different engine, will probably think carefully whether they can get a set of those advantages thanks to which power plants with multipoint injection have won worldwide recognition:

Simple device... This is not to say that it is easier than the carburetor models, but in comparison with TSI engines equipped with high-pressure fuel pumps and turbochargers, the superiority is obvious, which is reflected in the cost of the car, not so significant operating costs and the ability to carry out many types of repairs on their own.
Moderate requests for the quality of fuels and lubricants. This is especially important for Russia, as it guarantees the availability of gasoline and oils. High Quality always and everywhere is impossible. MPI engines are quite unpretentious and feel good when using low-octane gasoline at least 92nd.
Reliability. According to the developers, the minimum mileage without breakdowns for a car with MPI is at least 300 thousand km, but only on condition that the oil and filters are replaced on time.
Low probability of overheating.
Adjusting the ignition timing.
The presence of a system of engine mounts. It is based on the use of rubber mounts. And although this is not directly related to the engine device, it still affects its "health" and the comfort of the owner, since the supports effectively dampen noise and vibrations that occur during movement. An interesting fact is that the adjustment of the supports for the operation of the motor is carried out automatically.

Cons and disadvantages of MPI

Among the disadvantages that force us to abandon the purchase and operation of machines with Multi Point Injection in favor of the newest models, there are only two points:

Relatively high consumption fuel... With multipoint injection, such consequences cannot be avoided.
Lack of torque and low power. The fact that the mixing of fuel with air takes place in the intake ducts, and not in the cylinders, imposes certain restrictions. Cars with MPI cannot be classified as "high-spirited" and powerful; they are more designed for a leisurely move, and therefore drive lovers, most likely, will not like it. But such a car may well pretend to be a family car, because dynamics and power are not important for it.

If we compare all the possible pros and cons, then among the Russians there will certainly be many who believe with confidence that the power plants with MPI are still competitive. Obviously, they think so and German manufacturers who decided that for the Russian version of the Škoda Yeti the best option there will be just an MPI engine.

The MPI multi-point fuel injection system is used only on gasoline engines and is the most popular in the world. In this system, each cylinder is equipped with an individual injector that injects fuel directly upstream of the intake valve. Multipoint injection ideally meets the high environmental standards as well as the requirements for mixture formation in modern engines.

The basic principle of the MPI system

MPI stands for Multi-point injection, which means “multi-point injection”. Most often, such markings are found on European cars.

Multipoint injection system design

It consists of the following elements:

throttle valve;
distribution line or fuel rail;
(injectors);
mass air flow sensor or air pressure and temperature sensor;
fuel pressure control.

Distributed injection scheme

In such a power system, air from the atmosphere passes through air filter, and then through throttle enters the intake manifold. Further, it is distributed along the channels of the cylinders.

In turn, the fuel is supplied by means of a pump through the rail and to the injectors. The latter are located close to the intake valves of the cylinders, which reduces fuel loss and the likelihood of fuel settling in the intake manifold. The operation of the injectors is controlled by the engine ECU. The amount of fuel that should flow through the injectors is calculated by the control unit based on information about the modes, load and engine speed, as well as on the basis of information about the amount of air entering the system received from a whole complex of sensors (temperature, pressure). In accordance with the calculations, the ECU sends pulse signals to the electromagnetic injectors, bringing them into operation.

In addition to controlling the operating modes of the injectors, the control unit carries out regular diagnostics of the state of the injection system and, if any malfunctions are detected, it issues a corresponding error signal to dashboard("Check Engine").

MPI operating modes

Depending on the operating mode of the injectors, several types of system are distinguished:

Simultaneous injection. In such a system, all injectors open at the same time, supplying fuel to each cylinder. This arrangement represents an improved mono injection, since the ECU controls the opening and closing of all injectors as one opening. On the other hand, the amount of fuel supplied for each individual cylinder can be different.
Pairwise injection. The opening of the electromagnetic injectors occurs in pairs, but one works at the intake stroke, and the second at the moment. Currently, such a scheme is used only at the stage of starting the motor or in emergency mode.
Individual injection. This is the most commonly used arrangement, in which each injector is individually triggered on the intake stroke. To ensure their operation, a valve timing sensor is provided in the system. It is mounted on the camshaft and determines the response time of each injector depending on the position of the shaft. Fuel is injected into each cylinder once per engine cycle. The classic injector sequence is 1-3-4-2.

Differences of the MPI system

Many people confuse MPI with distributed injection in general, which also includes a direct injection system (FSI, DISI, TSI), in which fuel is supplied directly to each cylinder. This is an important distinction because multi-point injection involves the formation of an air / fuel mixture in the intake manifold passages ahead of the intake valves.

In addition, engines with multipoint multipoint injection are naturally aspirated, without the use of supercharging. This means that such engines have less stringent requirements for fuel quality.

Advantages and Disadvantages of Multipoint Injection

Fuel rail for distribution injection system

The main advantages of the distributed (multipoint) injection system are more economical fuel consumption and compliance with environmental standards in comparison with a single injection or a carburetor. On the other side, MPI engine less powerful than motors with direct fuel supply to the engine cylinders. At the same time, in comparison with systems with direct injection, it is less expensive to maintain.

The disadvantages of distributed injection include the complexity of manufacturing, and, as a result, high cost. This also applies to repairs. electronic system and injectors. Service and diagnostics require specialized equipment and highly qualified specialists.

For domestic conditions, multipoint distributed injection systems are considered the most optimal in terms of cost and ease of maintenance, as well as in terms of power output and comfort of operation.

The forthcoming publication is intended for experienced drivers who have changed a lot of 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 detailed description the principle of operation of a 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 engine model 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 was remembered by drivers with considerable experience injection motor MPI. 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 engine internal combustion, 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, there is a separate injector for each cylinder and a dedicated exhaust port for fuel delivery. Multi-point fuel supply is also characteristic of TSI motor, however, it differs in the presence of pressurization, which is absent in the engine under consideration.

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 and 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 is due to the excessive overheating of the space at the cylinder head.

A strong increase in temperature can cause the 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 mode of operation 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 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 contributes to an increase in the sensitivity index 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 you to maintain an acceptable temperature in the engine, protecting it from the formation of gas-air jams;
The advanced hydraulic drive control system makes it possible to significantly reduce the noise and vibration generated by a functioning motor.

Among other advantages of power units with the 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 in 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 can't 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 considered to be the power loss 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 refused 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.

MPI engine - means injection engine, which 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, the MPI system was the first for the Wolfsburg-based carmakers injection system fuel injection. Now this type of unit no longer meets 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 became in demand again! 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 engines 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 supplies fuel at a trivial pressure of 3 atmospheres to a special intake manifold, where it then mixes with air and is 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 the 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

Advantages

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 stringent 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 the Europeans.

Simplicity of design. Of course, this is not a carburetor, but also not a TSI with its pump. high pressure and a turbocharger. And the simplicity of the design automatically means the affordability of the unit itself and its possible repair.
Lower requirements for. The MPI engine does quite well on 92 petrol. And try to fill it, for example, in a modern Volkswagen passat... This kind of 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 do not have special requirements for fuel quality

Another advantage, however, not directly related with the 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. That's that. 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. Still, 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, then 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.

In the Russian version Skoda yeti installed MPI engine

Now, we think it will be clear what this is an MPI engine. If you have any questions about this article, please ask. We will definitely answer.

Surely everyone knows what a motor is in a car. but our today's article is devoted to a specific unit, about which we will try to tell from "A" and "I"

The end of the last century and the beginning of a new one became a period of heightened interest in MPI gasoline engines. The interpretation of this abbreviation sounds like Multi Point Injection. The extraordinary fuel injection scheme has served as a good demand for cars with such engines. This scheme was created according to the multi-point principle.

Individual injectors in each cylinder ensure the most uniform distribution of fuel in the cylinders. This design development, namely the launch of multi-point injection engines, was taken over by Volkswagen. Due to which later MPI engines appeared.

The emergence of such power plants constituted an alternative to carburetor engines. To better understand the MPI engine, you need to carefully analyze its competitive features.

Modernity of Multi Point Injection engines

There is no future for MPI engines, as it looked a few years ago, many even believed that the manufacture of motors of this type has been suspended. The radical development of automotive developments and technologies very quickly forces us not to remember yesterday's quality benchmarks.

In fact, this is what happens with MPI engines, many in the industry argue that efficiency and environmental friendliness are outdated.

But these conclusions are mostly true only for the European markets, and as for the Russian ones, here it all looks in part. Since the real potential of these units has not yet been fully revealed by domestic motorists.

Manufacturers relying on foresight do not let this technology die and are constantly introducing it on cars intended for Russian roads. For example, Skoda Yeti or Volkswagen Polo. The most memorable were the representatives of the MPI system with engines, the volume of which was 1.4 or 1.6 liters.

Design features of the MPI engine

The complete absence of a turbocharger is another significant feature of this system, along with the multipoint injection system. In the design of these engines there is a conventional gas pump, which, under a pressure of 3 atmospheres, supplies fuel to the intake manifold for subsequent mixture formation and supply of a ready-made composition through the intake valve.

This scheme of work is very similar to the scheme of work carburetor engines... With one difference, there is a separate nozzle for each cylinder.

Another unusual feature of the engine's Multi Point Injection system is the presence of a water cooling circuit for the fuel mixture. This is due to the fact that in the area of the cylinder head there is a very high temperature, and the pressure of the incoming fuel is very low, because of this there is a high probability of a gas-air lock and, consequently, boiling.

Inherent advantages of MPI

Before switching to a car with MPI, many motorists who are more or less familiar with this system will think very well about obtaining a set of advantages due to which multipoint injection installations have earned a vocation in the world.

Simplicity of the device

This does not mean that such systems are simpler compared to carburetor models. If we compare the TSI model, which has a high-pressure fuel pump and turbochargers in its design, then naturally superiority is evident. And the cost of the car will be lower and reduced operating costs and the ability to carry out self-repair.

Undemanding fuel quality inquiries

It is not possible to guarantee the proper quality of fuel and oils everywhere and always, which is very typical for Russia. The use of low-octane gasolines below 92 does not affect the performance of MPI engines, since they are very unpretentious. The minimum mileage of cars without breakdowns, according to the developers, is 300,000 km, subject to timely replacement of oil and filter elements.

Minimum overheating probability

The ignition timing is adjustable. The presence of a system of engine mounts, which is designed to use rubber mounts. Of course, this is not directly related to the engine, but it still matters for the performance of the engine and the comfort of the driver.

Because the supports dampen vibrations and various noises that occur when driving. An interesting feature is that the supports are automatically adjusted for different engine operating modes.

Typical disadvantages of MPI

All the disadvantages of this engine are expressed precisely by its design features... The connection of fuel with air occurs in the channels, and not directly in the cylinders. Accordingly, there is a limitation of the capabilities of the intake system. This is expressed in a lack of power and a rather weak torque.

Proceeding from this, decent dynamics, sporty throttle response, hot drive are not obtained. In modern cars, the presence of eight valves, as a rule, is not enough, so all these characteristics increase. If you characterize this car with such a system, then it will quite pass for a family and quiet transport.

That is why such cars are no longer in demand and recede into the background into the past. Why is this happening, i.e. the world made an assessment of the qualities of this system and decided that this was not enough for him and the designer, the developers began to design more modern motors by power. But no, there are unexpected surprises in the automotive industry.

The developers of Skoda, having developed the Russian version of the Yeti SUV for family use, in 2014 deliberately abandoned turbocharged engine with a displacement of 1.2 in favor of the MPI engine with a displacement of 1.6 and 110 hp.

As stated by the developers of the famous world concern, this engine has practically nothing to do with old model with a capacity of 105 hp. It suits TSI models best, but lacks direct injection and turbocharging.

Summarizing

All of the above indicators significantly affect the departure of engines from the world market with the MPI system. Many car enthusiasts these days prefer more powerful modern cars whose pace is steadily increasing.

The need to equip machines with more powerful units significantly underestimates the coefficient of demand for Multi Point Injection engines. Compared to them, this motor is rather weak. But it is still too early to write off the MPI engine completely, since the developers of the Skoda Yeti are trying to use it to the fullest on Russian roads.