An article about the MPI engine - features of the motor, its operation, advantages and disadvantages. At the end of the article - a video about the analysis of the MPI motor.
The content of the article:
At the end of the last century, MPI (Multi-Point-Injection) engines with multi-point distributed fuel injection replaced the carbureted ones and were considered the most advanced technology in engine building. This technology was developed by the Volkswagen Group. The first engine with the MPI system was installed in the Volkswagen Polo, and later they were used in the Golf and Jetta models.
Over the past few years, MPI engines have been installed only on Skoda models, and the last Skoda with MPI technology was the Skoda Octavia of the 2nd series (the 3rd series has already begun to be equipped with more modern engines - TSI and FSI).
Today, most of the experienced car owners with experience consider MPI engines long outdated and almost rarity. The experts from Volkswagen adhere to the same opinion, considering this type of engine no longer corresponding to the modern European requirements for efficiency and environmental friendliness.
However, despite this, MPI motors still have a reputation for being the most reliable and practical of all injection units. In addition, the MPI technology turned out to be in demand in Russia, where Volkswagen in 2015, at the Kaluga plant, launched a production line for assembling MPI motors of the EA211 series. This became possible due to the lower requirements in Russia for the environmental friendliness of engines compared to Europe.
Each cylinder has a separate injector with a nozzle!
The main feature of MPI-injection engines with distributed fuel injection is that each cylinder has its own separate injector with a nozzle. With the help of injectors, a metered injection of fuel is carried out into each individual cylinder, with atomization through the injectors. This method allows the fuel mixture to be evenly distributed over all cylinders. At the same time, unlike the TSI engine, the MPI design does not have a fuel rail and there is no direct fuel injection into the cylinder, which is available in the FSI and TFSI systems.
Important! Motors with MPI technology run ahead of ignition, which makes the gas pedal very sensitive to impact.
No turbocharger
Another significant feature of MPI engines is the complete absence of a turbocharger in their design with a multipoint injection system. Instead, MPI engines are equipped with a conventional gas pump with a pressure of 3 atm. The MPI system works as follows:
- from the gas tank, the fuel is pumped into the injector by a gas pump;
- the electronic injection control unit sends a signal to the injector and fuel is sprayed under pressure through the injector to the inlet cylinder valve.
- devices for delivering fuel to injectors;
- ignition block;
- device for dispensing air mass;
- device for adjusting the toxicity of exhaust gases.
Water cooling circuit
The water cooling circuit in MPI engines is designed to cool the combustible mixture. During operation of the unit, the cylinder head gets very hot and the fuel is supplied under low pressure. As a result, there is a great danger of a gas-air lock, which can lead to overheating with boiling. The presence of a water cooling circuit for the combustible mixture prevents the occurrence of such overheating.
The fuel-air mixture for MPI engines must have the following quality characteristics:
- Gaseousness. For efficient combustion of the fuel-air mixture, complete evaporation of gasoline must occur before it starts to ignite.
- Homogeneity (uniformity). The evaporated fuel must mix well with the oxygen in the air mass. Incomplete fuel mixing in oxygen rich areas increases the risk of knocking. In places with increased enrichment, the fuel does not burn completely, which leads to a decrease in the engine efficiency.
- The volume of fuel pumped in must be proportionally sufficient to mix with the air pumped into the cylinder. For example, for a more complete combustion of the fuel-air mixture, you will need to mix 1 kg of gasoline with 14.7 kg of air mass. With an increase or decrease in the amount of air, either depletion or re-enrichment of the fuel mixture will occur, respectively. However, it should be remembered that the narrowness of the range of proportional change in the composition of the mixture leads to a low efficiency of a gasoline MPI engine, for example, compared to the cycle of a diesel internal combustion engine.
Hydraulic drive control mechanism
MPI engines are equipped with a special hydraulic control mechanism, with a clutch with a grease nipple to limit trims. Additionally, the specified control mechanism is equipped with special soft mounts that automatically adjust to the operating mode of the engine and reduce noise with vibration.
MPI motors have the following advantages:
- Proportional precision when mixing fuel with air. Fuel is injected through injectors directly onto the cylinder intake valves, eliminating the possibility of uneven filling. The moment of fuel injection through the injector is precisely determined by the controlled impulse. The amount of fuel supplied will depend on the duration of the open state of the injector.
In general, the fuel system is controlled by an ECU (Electronic Control Unit) or, more simply, an on-board computer. The control unit (ECU) is able to calculate (based on information from the sensors) not only the injection moment, but also the required amount of fuel to prepare a high-quality fuel-air mixture.
- Minimum losses during gasoline evaporation. The close arrangement of the injectors to the intake valves eliminates the need for significant re-enrichment of the combustible mixture to warm up the engine. Also, the proximity of the injectors to the valves allows the fuel to remain in the liquid state longer after injection, which leads to a decrease in the glow in the combustion chamber. With an increase in the degree of resistance to detonation, it is possible to change the compression ratio with increasing engine power.
- Increased pressure injection stroke. Increasing the injection pressure makes it possible to convert the fuel into a fine dispersion, which significantly improves the combustion of the fuel-air mixture.
- Thanks to the ability of the ECU (Engine-ECU) to read certain data (revolutions, speed, actual and recommended load, etc.), an accurate calculation of the injection time and the amount of gasoline takes place. This allows MPI engines to deliver optimum power with relatively low fuel consumption.
In addition, the simplicity of the engine design saves on repair costs. Also, the design of the MPI engine compares favorably with the more complex designs of TSI engines, which have rather complicated and expensive high-pressure pumps and turbochargers to repair. Plus, the MPI motor is smaller and less likely to overheat.
MPI advantage over carburetor and mono-injector
The advantage of the MPI system is due to the disadvantages of carburetors and mono injectors. Simply put, MPI technology was developed in order to eliminate the disadvantages of carburetor and monoinjection technologies, which did not allow accurate metering of fuel delivery and reduce fuel loss during engine warm-up.
Technologically, the fuel was supplied through the carburetor (or mono-injector) directly to the intake manifold, which led to increased fuel consumption and greater exhaust toxicity. When the engine was cold started, most of the incoming fuel condensed (settled) on an unheated manifold, as a result of which the fuel-air mixture had to be re-enriched.
Disadvantages of MPI motors
- Slow start and acceleration. According to experienced drivers, MPI motors are less dynamic. And indeed it is. Loss of dynamism occurs during mixing of fuel with air directly in the exhaust ducts, before it is fed into the cylinders. The fact that MPI motors are not designed for quick start and acceleration is also indicated by the presence of an 8-valve system with a timing set.
- Small profitability. MPI engines are inferior in fuel economy to TSI engines with supercharging and direct fuel supply to the cylinder.
Judging by the same reviews on the Internet, the problem with knocking during a cold start affected the CWVA motor modification (with the same volume of 1.6 liters) less. But the price to pay for the elimination of knocking was an even greater waste of oil. The fact is that the increase in the load on the CPG during a cold start, the designers from Volkswagen decided to compensate with new oil scraper rings, leaving a thicker layer of oil on the cylinder walls.
Motors with MPI technology are perfect for use in Russian conditions.
- They are not demanding on the quality of fuel, which is important for the Russian fuel market. Indeed, until now, fuel at many Russian gas stations is not of high quality. But MPI motors are able to work well and for a long time even on gasoline with an exorbitant sulfur content.
- Simple and reliable, with additional protection against mechanical stress, the design of the MPI engine is also relevant for Russian roads, most of which (as well as fuel) are not of high quality.
- MPI engines comply with Russian emission standards, in contrast to Europe, where the environmental requirements for engines are much higher.
MPI motor disassembly video:
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 multipoint principle.
Separate 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 production of engines of this type had 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 partly. Since the real potential of these units has not yet been fully revealed by domestic motorists.
Manufacturers who rely 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 absolute absence of a turbocharger is another significant distinguishing 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 the finished composition through the intake valve.
This operation scheme is very similar to the operation scheme of 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 \u200b\u200bthe 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 possibility of 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. According to the developers, the minimum mileage of cars without breakdowns is 300,000 km, subject to timely replacement of oil and filter elements.
Minimum overheating probability
The ignition timing is adjustable. The presence of an engine mount system, 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 various 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 straight 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's developers began to design more modern motors in terms of 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 the turbocharged engine with a volume of 1.2 in favor of the MPI engine with a volume of 1.6 and 110 hp.
According to the developers of the famous world concern, this engine has practically nothing in common in comparison with the old model with a capacity of 105 hp. It fits best with the TSI models, but it 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. These days, many car enthusiasts prefer the more powerful modern cars, which are steadily increasing in pace.
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.
Multi Point Injection - a new type of gasoline engine with a pre-installed multi-point 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 engineers of the company are considered to be the inventors of the technology. They are the first to develop an alternative to the carburetor type. Let's take a closer look at how the MPI engine works and how efficient it is.
How does Multi Point Injection correspond to the present
A number of automakers in Europe and Asia believe that this type has no future, since the rapid development of technology will quickly leave behind the "novelty". This is partly true. Only Volkswagen and its structural divisions, including Škoda, are actively developing and supporting MPI. Business card: engines 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 the fuel mixture to the intake manifold under high pressure. The working indicator is three atmospheres;
- through the inlet valve of the injector, the fuel enters the inside of the cylinder, where ignition occurs, the 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 the temperature above the cylinder head is elevated, and the fuel is supplied under low pressure. The consequences are negative, the risk of boiling, the formation of a gas-air lock. The operation of the power unit is impossible without a third-party cooler.
MPI advantages
- simplicity of design. Obviously, such engines are simpler than power units equipped with TSIs with turbochargers, but not a carburetor type. The owners carry out a number of repairs on their own, without resorting to the help of service station specialists. Clear savings on monthly maintenance;
- loyalty of the system to the quality of fuel. As applied to the CIS countries, where 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 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 damp vibrations, vibrations during operation.
Disadvantages of MPI
- increased fuel consumption. The factor is quite controversial, it can be interpreted in different ways. In comparison, it is increased by 7%. This frightens off many potential buyers, repels;
- low torque, and as a result, an average power factor. The fuel mixture is mixed directly in the intake ducts, not in the cylinders. This is atypical for most constructs and causes confusion among TSI constructors.
Cars with pre-installed MPI are not considered high-spirited, fast, or active. Rather, the average level for connoisseurs of a leisurely drive, family rest.
Sales statistics for the CIS and the Russian Federation, including, show that for owners, the power indicator is still a priority, rather than practicality.
Common symptoms of MPI failure
- decrease in power during driving;
- increased fuel consumption;
- an indicator on the presence of a “Check Engine” malfunction signals on the central dashboard;
- exhaust in blue, white or black comes out of the tailpipe. At the same time, this indicates a faulty injector and fuel equipment;
- unstable idling;
- difficult cold start;
- increased working sound, vibration.
Common causes of breakdowns
- violation, ignoring the timing 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 a machine, power unit;
- inconsistency of temperature conditions, oil viscosity indices;
- systematic loads in excess of the norm.
Difference between TSI and MPI
(double supercharging with stratified injection) - this is how the abbreviation TSI stands. This interpretation was provided by Volkswagen engineers at the initial stage. After, it was renamed Turbo Stratified Injection. Now the abbreviation is used by many concerns, only with the addition of a few letters to distinguish it.
Differences between the two types:
- TSI has a standard inflation system. The motor can simultaneously have two superchargers: a turbocharged compressor and a mechanical type;
- there are no blowers in MPI, they are not provided by the design. When it comes to MPI, they mean atmospheric-type power units;
- TSI puts forward a number of requirements for engine oil, viscosity index, replacement frequency;
- in the TSI, fuel is injected directly into the cylinder cavity. For this, a special-shaped head, pistons, fuel injectors are made;
- in MPI, the 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 nominal pressure is sufficient to supply fuel.
In case of breakdowns, MPI repair will cost several times cheaper than TSI. This factor is powerful, for many potential owners it is fundamental.
But there is one more, no less popular, which is installed on Volkswagen Group cars (now mainly on SKODA cars), this is the MPI engine. It should be noted that this engine is the oldest of the Volkswagen engine range, but it is the most reliable and practical of all units ...
MPI or Multi Point Injection engine - non-turbo gasoline engine using multi-point multi-point fuel injection through injectors. One injector is used per cylinder, there is no fuel rail as in TSI engines, and there is also no fuel injection directly into the engine cylinders as in FSI and TFSI engines. The MPI engine has its own fuel injection structure. To put it bluntly, there is one injector per cylinder, through a special intake channel. It should be noted that it was he who replaced the carburetor engines.
Such an engine has the function of advancing the ignition process, which provides high sensitivity values \u200b\u200bof the gas pedal throttle.
The building has a water-cooled MerCruiser fuel mixture that cools the fuel mixture to an acceptable temperature. Such cooling allows to increase the stability of the engine by getting rid of air - gas locks.
It also has an advanced hydraulic control system. A coupling with a grease nipple. Memory trim limiting system (based on rubber mounts that automatically adjust to engine performance - reducing noise and vibration during operation).
Has an 8 valve gas distribution system, two valves per cylinder, one camshaft. The brightest representatives of this family are engines 1.4 (80 hp) and 1.6 liters (105 hp).
AdvantagesMPI
The engine is unpretentious, it can run on 92 gasoline. It has a solid design, as the manufacturer himself assures, the minimum mileage without repair is 300,000 kilometers, with timely replacement of oil and filters. Not expensive and not complicated repair, due to a simple device.
disadvantagesMPI
Due to the fact that the fuel mixture is mixed in special intake channels before entering the cylinders, such engines have limited intake system capabilities. This affects the power and. They cannot be called "dynamic" and powerful. Most likely, they are designed for a leisurely ride. The presence of eight valves, and most of these engines have eight valve timing systems, also indicates a loss of power.
Due to their old design, MPI engines are gradually phased out of production, the last models on which this engine family was installed were the second generation SKODA OCTAVIA cars. However, the third generation of OCTAVIA vehicles has more modern and advanced FSI and.
I think it became a little clear what this engine is.
Many modern injection engines are equipped with different fuel injection systems. Mono injection, and even more so the carburetor, has long gone into history, and now there are two main types - the distributed and direct type (on many cars they are "hidden" under the abbreviations MPI and GDI). However, a common man in the street really does not understand what the difference is, and also which one is better. Today we will close this gap at the end there will be a video version and voting, so read-watch-vote ...
You really came to the salon, you look at the configuration, and there are solid MPI or GDI, there may also be TURBO options. You start asking a consultant, and he unambiguously praises direct injection, but distributed injection (well, if you don't have enough money). BUT why is he so good then? Why overpay, and is it spent on it?
Distributed or multi-point fuel injection
Let's start with him, all because he appeared first (in front of his opponent). Prototypes existed at the dawn of the 20th century, although they were far from ideal and often used mechanical control.
Abbreviation MPI (Multi Point Injection) - multipoint multipoint injection. In fact, this is a modern injector.
Now, with the development of electronics, the carburetor and other power systems that were at the dawn are becoming a thing of the past. Distributed injection is an electronic power system, which is based on injectors (from the word injection), a fuel rail (where they are installed), an electronic pump (which is attached to the tank). It's just that the ECU gives orders to the pump to pump fuel, it goes along the highway to the fuel rail, then to the injector and then sprayed at the level.
But this system has also been polished over the years. There are three types of injection:
- Simultaneous ... Earlier, in the 70s and 80s, no one cared about the price of gasoline (it was cheap), and no one thought about the environment either. Therefore, fuel was injected into all cylinders at once, with one revolution of the crankshaft. It was extremely impractical, because as usual (in a 4-cylinder engine) - two pistons work on compression, and the other two discharge exhaust gases. And if you supply gasoline to all the "pots" at once, then the other two will simply throw it into the muffler. It is extremely expensive in terms of gasoline and very harmful to the environment.
- Parallel-pair ... This type of distribution injection, as you probably already guessed, occurred in two cylinders in turn. That is, the fuel went exactly where compression is now taking place.
- Phased type ... This is the most advanced method at the moment, here each nozzle lives "its own life" and is controlled separately. It delivers gas just before the intake stroke. This is where the maximum economy of the mixture occurs, as well as a high environmental component.
I think this is understandable, it is the third type that is now installed on all modern car models.
WHERE IS THE INJECTOR ... This is the main difference between distribution injection and direct injection. The injector is at the level of the intake manifold, next to the engine block.
The mixing of air and gasoline takes place in the manifold. Metered air comes from the throttle valve (which you regulate with the gas pedal), when it reaches the nozzle, fuel is injected, a mixture is obtained, which is already drawn through the intake valves into the engine cylinders (further compression, ignition and exhaust gas discharge).
PLUSES such a method can be called the relative simplicity of the design, low cost, also the injectors themselves should not be complex and resistant to high temperatures (because I have no contact with the combustible mixture), they work longer without cleaning, they are not so demanding on the quality of the fuel.
MINUSES more fuel consumption (compared to the opponent), less power
BUT, due to their simplicity, low cost and unpretentiousness, they are installed on a large number of engines, not only in the budget segment, but also in the D-class.
It appeared not so long ago, in 80 - 90 years of the last century. Such brands as MERCEDES, VOLKSWAGEN, BMW, etc. were actively involved in development.
Abbreviation GDI (Gasoline Direct Injection) - injection directly into the combustion chamber
The injection is carried out according to the phased type principle, that is, each injector is controlled separately. Often they are fixed in a high pressure rail (something like a COMMON RAIL), but there are also individual fuel elements suitable for each separately.
WHAT IS THE DIFFERENCE HERE - the injectors are screwed into the engine block itself and have direct contact with the combustion chamber and the ignited fuel mixture.
Air is also supplied through the throttle, then through the intake manifold - through the valves it enters the engine cylinders, after which fuel is injected during the compression cycle, mixing with air and igniting from the spark plug. That is, the mixture takes place directly in the engine, and not in the intake manifold, this is the main DIFFERENCE!
PROS. Fuel efficiency (can reach up to 10%), high power (up to 5%), better ecology.
MINUSES ... You need to understand the nozzle is next to the ignited mixture, it follows from this:
- Complex construction
- Complex service
- Expensive repair and maintenance
- Requirement for fuel quality (otherwise it will be clogged)
As you can see, it is efficient and technologically advanced, but expensive to maintain.
Which is better - a table?
I propose to think about it, made a table on the advantages of both types
As you can see, both types have significant advantages over the other, apparently while both exist.
Now we are watching the video version.
