The upcoming publication is intended for experienced drivers who have changed a lot of cars. Today, an MPI-marked engine is considered a rarity, superseded by more advanced innovations. 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 shortcomings and evaluate its merits. Also in this article you can find a detailed description of the principle of operation of a complex mechanism with the MPI index.

What was good about the MPI engine, memories of achievements in the automotive industry

Some confirmation of the well-known saying that nothing lasts forever in our ghostly world is the gradually disappearing popularity of the MPI-marked power unit. At one time, it was considered a very successful replacement for carburetor engines, a certain innovation in 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 TSI, FSI or BSE engines, which appeared in 2005, are better known to contemporaries. 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. During the launch into production, it was considered the cutting edge of the domestic automotive industry.

What drivers with considerable experience remember the MPI injection motor. What are the features of its principle of operation, what are the undeniable advantages and annoying shortcomings. Further information will answer the questions of curious motorists.

The principle of operation of the MPI power plant

To begin with, it is necessary 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. However, it deserves separate consideration.

Fuel is supplied simultaneously from several points. As mentioned earlier, each cylinder has its own injector, and a special exhaust port is dedicated to supplying fuel. Multi-point fuel supply is also characteristic of the TSI engine, however, it is distinguished by the presence of supercharging, 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. It forms a mixture of gasoline with air, 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:

1. First, fuel from the gas tank is pumped into the injector;
2. After receiving a certain signal from the electronic control unit, the injector sends fuel to a special channel;
3. In this direction, the fuel mixture is delivered to the combustion chamber.

Some similarity of 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 increase in temperature can cause the fuel under low pressure to boil. The resulting gases can form undesirable gas-air plugs.

Another distinguishing feature of the MPI engine is the presence of a specific hydraulic drive control mechanism, consisting of a clutch equipped with a grease fitting, and a special system that sets certain limits for trims.

It is usually represented by rubber bearings, the distinguishing feature of which is the ability to independently adapt to the mode of operation of the power unit. Their main purpose is to reduce noise and vibration during engine operation.

The design of the motor with the MPI index 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 you to maintain an acceptable temperature in the engine, protecting against the formation of gas-air plugs;
• An advanced system that controls the hydraulic drive makes it possible to significantly reduce the noise and vibration produced 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 on gas stations;
• Reliability and structural strength. 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 device of the power unit is reflected in the cost and complexity of the repair.

You can not do without a fly in the ointment, which somewhat detracts from the listed advantages of the MPI motor. In our case, a significant drawback of such engines is the loss of power due to the limited intake system. However, although the units in question lose their dynamism due to the presence of eight valves in the timing mechanism, a measured, calm ride is ensured with their help.

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 models of Volksvagen cars were equipped with such motors, today they are installed only on the second generation Skoda Octavia.

The design of power units is considered obsolete and is gradually being phased out, being replaced by high-tech innovations.

Multi Point Injection- a new type of gasoline engine with a pre-installed multipoint fuel injection system. Each cylinder has a built-in injector, as a result of which the combustible mixture is evenly and proportionally distributed around the perimeter. The company's engineers are considered to be the inventor of the technology. They are the first to develop an alternative to the carbureted type. Let's take a closer look at how the MPI engine works and how efficient it is.

How modern is Multi Point Injection

A number of automakers in Europe and Asia believe that this type has no future, as the rapid development of technology will quickly leave the “novelty” behind. This is partly true. Only the Volkswagen concern and its structural subdivisions, including Škoda, are actively developing and supporting MPI. Business card: engine with volumes of 1.3, 1.4 and 1.6 liters.

The main feature of the power unit is the absence of any turbocharged supercharger. The design is simple and intuitive:

• a gasoline pump that supplies a combustible mixture to the intake manifold at high pressure. Operating indicator three atmospheres;
• through the inlet valve of the nozzle, fuel enters the cylinder, where ignition occurs, exhaust gases are removed.

Multi Point Injection is equipped with a water-cooled combustible mixture. It sounds unusual, it's hard to imagine, but the system works successfully. The presence of a non-standard design is explained by the fact that there is an increased temperature above the cylinder head, and the fuel is supplied under low pressure. The consequences are negative, the risk of boiling, the formation of a gas-air plug. Without a third-party cooler, the operation of the power unit is impossible.

Benefits of MPI

• simplicity of design. Obviously, such engines are simpler than power units equipped with TSI with turbochargers, but not carbureted type. A number of repairs are carried out by the owners on their own, without resorting to the help of service station specialists. Explicit savings on monthly maintenance;
• loyal attitude of the system to the quality of fuel. With regard to the CIS countries, where the fuel is not always "good", this option is acceptable. The power unit runs quite comfortably on AI-92 gasoline;
• the average service life before overhaul is 300,000 km. These figures are given by the manufacturer. In practice, the resource is less than 50,000 km. Few people take into account the factor of timely replacement of engine oil, cleaning elements, refueling with high-quality fuel;
• minimal risks associated with overheating;
• the possibility of mechanical adjustment of the ignition timing;
• the design provides for the presence of rubber mounts above the engine. This allows you to dampen vibrations, vibrations during operation.

Disadvantages of MPI

• increased fuel consumption. The factor is quite controversial, it can be interpreted in different ways. In comparison with it is increased by 7%. Many potential buyers are deterred, repelled;
• low torque, and as a result, an average power factor. The fuel mixture is mixed directly in the intake ports, not in the cylinders. This is not typical for most designs, causing misunderstanding among TSI designers.

Cars with pre-installed MPI are not considered frisky, fast, active. Rather, the average level for connoisseurs of a leisurely drive, family vacation.

Sales statistics for the CIS and the Russian Federation, among other things, show that for owners, the indicator of power remains a priority, rather than practicality.

Typical symptoms of an MPI malfunction

• power loss while driving
• increased fuel consumption;
• on the central dashboard, the indicator indicates the presence of a malfunction "Check Engine";
• blue, white or black exhaust comes out of the exhaust pipe. At the same time, this indicates a faulty injector and fuel equipment;
• unstable idling;
• difficult start on the "cold";
• increased working sound, vibration.

Common causes of breakdowns

• violation, ignoring the terms of the technical inspection;
• third-party technical (mechanical) damage, accidents, collisions, impacts;
• installation of non-original parts, components, consumables;
• refueling with low-quality fuel with a high content of chemical impurities;
• violation of the rules for using the machine, power unit;
• discrepancy between temperature regimes, oil viscosity indices;
• systematic loads above the norm.

Difference between TSI and MPI

(twin supercharging with layered injection) - this is how the abbreviation TSI stands for. This interpretation was given by Volkswagen engineers at the initial stage. After that, it was renamed Turbo Stratified Injection. Now the abbreviation is used by many concerns, with only a few letters added to distinguish it.

Differences between the two types:

1. TSI has a standard inflation system. There can be two superchargers in the engine at the same time: a turbocharged compressor and a mechanical type;
2. there are no superchargers in MPI, they are not provided for by the design. When it comes to MPI, they mean atmospheric-type power units;
3. TSI puts forward a number of requirements for engine oil, viscosity index, replacement intervals;
4. in TSI, fuel is injected directly into the cylinder cavity. For this, a special-shaped head, pistons, fuel nozzles are made;
5. in MPI, fuel enters initially into the intake manifold, and then into the cylinder at the moment the valves open. For such a design, the presence of a gasoline pump is not at all necessary, since the standard pressure is sufficient to supply fuel.

In the event of breakdowns, repairing MPI will cost several times cheaper than TSI. This factor has significant power, for many potential owners it is fundamental.

MPI engine in Volkswagen cars: principle of operation, features, advantages and disadvantages. The MPI engine is an injection design that uses a multi-point fuel injection device. Therefore, this motor received the appropriate name "Multi-Point-Injection". In other words, each engine cylinder has its own injector nozzle. It was this scheme that was embodied by the Volkswagen concern.

This type of engine is installed in the Volkswagen New Polo sedan, some Golf and (partially Golf and Jetta are also equipped with TSI engines). On the Passat CC, now (2016) only TSI engines are installed. On install FSI.

The MPI engine is the most outdated of the entire Volkswagen engine range. But, nevertheless, it is distinguished by excellent practicality and reliability. Some experts note that now this type of engine does not meet current requirements in terms of efficiency and environmental friendliness. Moreover, until recently it could be argued that this type of motor was discontinued. And the last car model of the automaker, where it was used, was the Skoda Oktavia 2nd series.

But suddenly the MPI engine was reborn and in demand again. In the fall of 2015, Volkswagen launched a production line of engines at its Kaluga plant, where they began to produce the MPI 1.6 engine design of the EA211 series.

MPI engine features

The main difference between such engines has already been written - this is a multi-point supply of gasoline. But those who are good with car engines may note that TSI engines also have multi-point injection.

Therefore, we turn to another distinguishing feature - there is no boost in MPI. Those. there are no turbochargers to force the mixture of fuel into the cylinders. An ordinary gasoline pump that supplies fuel at a pressure of three atmospheres to a special intake manifold, where it is further mixed with the air mass and drawn through the intake valve directly into the cylinder. As you can see, this is quite similar to the activity of a carburetor engine. There is no direct fuel injection into the cylinder, as in FSI, GDi or TSI devices.

Another feature is the presence of a water system, due to which the fuel mixture is cooled. This is due to the fact that an increased temperature regime is established in the area of ​​\u200b\u200bthe cylinder head, and gasoline is supplied at a rather low pressure. Because all this can boil and form gas air locks.

Advantages

The MPI engine is distinguished by its own unpretentiousness in terms of fuel quality and can operate on 92nd gasoline.

By design, this motor is very durable, and its smallest mileage without any repair work, as the manufacturer informs, is 300 thousand km, of course, if oils and filters are changed on time.

Due to its not very complex design, the MPI engine can be easily and inexpensively repaired in the event of a breakdown, and in general this is noticeably reflected in its price. The conventional design sets it apart from the TSI, which has an overpressure pump and turbocharger. The MPI engine is also less likely to overheat.

Another advantage of the motor is the presence of rubber supports located directly under the engine. This greatly reduces noise and jitter during movement.

Flaws

It can be noted that the MPI engine is not very dynamic. Due to the fact that the fuel mixing process is carried out in special exhaust channels (before the fuel enters the cylinders), such engines are considered limited. An eight-valve system with a timing kit indicates a lack of power. Thus, they are designed for not very fast trips.

Among the disadvantages, one can single out that MPI is less economical. Multi-point injection is inferior in efficiency to supercharging together with direct fuel injection into the cylinder, as is done in the TSI propulsion system.

And yet, if we add up the advantages and disadvantages, it turns out that these engines are quite comparable in terms of competitiveness, especially for Russian roads. It is no coincidence that German manufacturers abandoned the 1.2-liter TSI engine for the Skoda Yeti, preferring the proven and unpretentious 1.6-liter MPI engine.

The period of increased interest in MPI gasoline engines (the abbreviation stands for Multi Point Injection) came at the end of the past and the beginning of this century. The demand for cars with such installations is due to a 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 idea of ​​an automobile engine with multipoint injection was implemented by Volkswagen, which greatly contributed to the emergence of an effective alternative to carbureted engines in the form of MPI. We will try to consider in more detail what an MPI engine is and evaluate its competitive sides.

How modern is Multi Point Injection

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

If such conclusions are true for the European market, 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 allow the technology to “die” and are still actively implementing it, for example, in the case of the second series of Škoda Octavia, Volkswagen Polo, Volkswagen Golf 7, Škoda Yeti for Russian roads, etc. The most memorable representatives from MPI in recent years steel engines of 1.4 and 1.6 liters.

MPI - the engine as it is

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

Multi Point Injection engine is equipped with a water-cooled fuel mixture, which is somewhat unusual. Such a move is dictated by the fact that in the region 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 plug.

Pros and Benefits of MPI

Compatriots who are already 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. It cannot be said that it is simpler than that of carbureted models, but in comparison with TSI engines equipped with high-pressure fuel pumps and turbochargers, the superiority is obvious, which is expressed in the cost of the car, not so significant operating costs and the ability to carry out many types of repairs yourself.
• Moderate requests for the quality of fuels and lubricants. For Russia, this is especially important, since it is impossible to guarantee the availability of high-quality gasoline and oils always and everywhere. MPI engines are quite unpretentious and feel good when using low-octane gasoline not lower than 92.
• 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 changed on time.
• Little chance of overheating.
• Ignition timing adjustment.
• The presence of the engine support system. It is based on the use of rubber supports. And although this is not directly related to the engine device, it still affects its “health” and comfort of the owner, since the supports effectively dampen the noise and vibration 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 minuses that make you refuse to buy and operate machines with Multi Point Injection in favor of the newest models, there are only two points:

• Comparatively high fuel consumption. With multi-point injection, it is impossible to avoid such consequences.
• Lack of torque and low power. The fact that the mixing of fuel with air occurs in the intake channels, and not in the cylinders, imposes certain restrictions. Cars with MPI cannot be classified as "frisky" and powerful; they are more designed for a leisurely move, and therefore lovers of drive, most likely, will not like it. But such a car may well qualify for the role of a family car, because dynamics and power are not the main thing for it.

If we correlate 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, German manufacturers also think so, having decided that the MPI engine would be the best option for the Russian version of the Škoda Yeti.

We will talk about the design of an internal combustion engine with multi-point injection, because this is how the decoding of the abbreviation MPI (Multi Point Injection) sounds in translation. Before the advent of direct injection gasoline power units (FSI, TSFI,), it was the MPI engine that was installed on the entire model range of Volkswagen, Seat, Skoda, Mitsubishi, Renault, Ford and cars from many other manufacturers. Consider the device, principle of operation and design features of the multi-point injection system for valves.

Design

Schematic representation of the Mitsubishi Motors multipoint injection system. The design is quite typical, so you can see an almost identical structure on Volkswagen, Skoda cars. The main difference will be in the way the amount of air is calculated. The diagram shows a design using an absolute pressure sensor (MAP) and a temperature sensor (DTV). Also in MPI engines, the amount of air entering the cylinders can be calculated by a mass air flow sensor (MAF) and a Karman type sensor.

The main components of the MPI electronically controlled fuel injection system:

• fuel supply system;
• ignition system;
• air calculation system;
• exhaust gas toxicity control systems.

Fundamentals of the principle of operation

The requirements that the air-fuel mixture of a gasoline engine must meet:

• be in a gaseous state. In other words, for effective combustion, before the moment of arson of TPVS, gasoline must completely evaporate;
• be homogeneous. The gaseous state contributes to good mixing of the fuel with the oxidizer (oxygen that is in the air). Uneven mixing in areas with a large amount of oxidizing agent increases the risk. In areas with significant re-enrichment, gasoline will not burn completely, which will lead to a decrease in engine efficiency;
• the amount of fuel supplied must correspond to the mass of air entering the cylinders. For the most complete combustion of TPVS, it is necessary to mix 1 kg of gasoline with 14.7 kg of air. By increasing or decreasing the proportion of air, we get an economic (lean) or power (enriched) composition of the fuel mixture. But the range of change in proportions in the composition is rather narrow, which partly explains the relatively low efficiency of a gasoline engine with an MPI injection system (for example, in comparison with).

Supply system

Modern engines are increasingly equipped with hybrid injection, in which separate nozzles inject fuel both at the valves and directly into the combustion chamber. Manifold injectors are used as an auxiliary system to flush deposits from intake valves.

Features of motos Volkswagen, Skoda

You can find a lot of bad reviews about the 1.6L MPI engines that have been installed on many VAG-Group models (Skoda Yeti, Octavia, Volkswagen Polo Sedan). Most likely, most of them will be about CFNA models, which, with relatively low mileage, begin to knock on the cold and consume oil. But this is not connected with the distribution injection on the MPI valves, but with the design features of the cylinder-piston group.

Judging by the reviews, to a lesser extent, the problem of knocking on a cold touched the 1.6 CWVA engines. The payment for this was . Volkswagen engineers compensated for the increased load on the CPG with the design of oil scraper rings, which are required to leave a large amount of oil on the cylinder walls. Andrei Krutsko will tell you more about the problem of atmospheric MPI engines for Skoda and VW.