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 production of this type of engine 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this is what happens with MPI engines, many in the industry argue that efficiency and environmental friendliness are outdated.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 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 operation 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 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 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 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'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.
As the developers of the well-known world concern stated, this engine has practically nothing in common compared to the old 105 hp model. 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. 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.
The MPI engine is slowly becoming a thing of the past. Not everyone knows what it is, mainly those who have changed a lot of 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 trouble-free among all injection engines.
MPI engine: what it is is quite simple to explain. Indeed, it is based on a commonly used injector, only with 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 metered through a dedicated intake port.
The design does not provide for a fuel rail, as injection injection is implemented 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 Volkswagen, it is a MerCruiser, which stabilizes the operation of the engine thanks to a developed system for releasing 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, the vibration of the motor and the 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.
Dignity
The main advantage of this engine is the simplicity of the device. 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 you deal with German cars with such an engine, the manufacturer guarantees a maintenance-free mileage of 300,000 - if you are not lazy to change filters and oil on time.
Related article: " ?"
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. We can say that this is a family and leisure car.
MPI and modernity
But by the way, according to the assurances of the developers from the world-famous concern, this engine has little in common with the old version of 105 horsepower. At its core, it rather belongs to the TSI family, but it does not have turbocharging and direct injection for gasoline.
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.
In such a power supply system, air from the atmosphere passes through the air filter, and then enters the intake manifold through the throttle valve. 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 on the 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 hand, the MPI engine is 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 the repair of electronic systems 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.
MPI engines are gradually becoming a thing of the past, so it is less and less common to meet a car enthusiast who understands what it is about when they call this abbreviation. Those who have changed a lot of cars or are interested in cars in general know about it.
Having replaced carburetor engines, becoming the next step in the development of the automotive industry, this type of engine is now giving way to advanced developments. Today, many people think in advance which engine should be on a personal car: TSI, FSI or MPI. Although, until now, many experts consider the latter the most practical, reliable and trouble-free in the family of injection engines.
FSI is considered a more modern development, the next step after MPI. The BSE engine appeared in 2005 and is famous for being well tolerated by the poor quality of domestic fuel.
Did you know? The abbreviation MPI comes from the term Multi Point Injection, which means multipoint fuel injection. The motor was actively used at the Volkswagen concern. It was gradually introduced at the Skoda subsidiary. The motors were also installed there for the last time - on the Yeti and Octavia models.
It should also be explained what MPI and TSI are. If the first term means an internal combustion engine, in which each cylinder has its own injector, then TSI has different interpretations.
So, initially, the abbreviation meant double supercharging and stratified injection: Twincharged Stratified Injection. But recently, the abbreviation TFSI has become increasingly used, in which the additional letter F stands for Fuel - fuel.
You can often find another abbreviated name of the engine - MPI DOHC, which means it is easy to understand if you know that the term DOHC refers to engines in which there are 2 camshafts and 4 valves in the cylinder head.
Principle of operation
The MPI fuel injection system delivers fuel from multiple points simultaneously. Each cylinder has its own injector, and fuel is supplied through a dedicated exhaust channel. But what distinguishes the MPI engine from the TSI, which is also equipped with a multi-point fuel supply, is lack of pressurization.
The fuel mixture is supplied to the cylinders not with the help of turbochargers, but with the help of a gas pump. It pumps gasoline into a special intake manifold under pressure of three atmospheres, where it mixes with air and is also sucked into the cylinder through the intake valve under pressure.
Schematically, the engine looks like this:- The fuel pump pumps fuel from the tank to the injector.
- A signal is sent from the electronic injection control unit to the injector, which passes fuel into a special channel.
- The mixture is directed to the combustion chamber.
The hydraulic drive control system consists of a clutch with a grease fitting and a system that limits trims. It includes rubber mounts that can independently adjust to the engine operating mode, reducing noise and vibration during operation. The engine has 8 valves: 2 for each of the cylinders, as well as a camshaft.
Did you know? The most common engines are the MPI 1.4 with 80 horsepower and 1.6 with 105 horsepower. But automakers are still gradually abandoning them. The only ones who still use engines of this type are the Dodge and Skoda companies.
Dignity
The engine has several advantages, the main of which is - simplicity of the system. This makes it easy to repair and maintain. For repairs, it is not always necessary to completely disassemble the entire structure. It can run on 92 gasoline.
In addition, its overall construction is very robust. In most cases, you can drive up to 300 thousand km without repairing the engine. Of course, if you maintain it properly: change the oil and filters on time.
disadvantages
However, it was the design features of the MPI engine that provoked its shortcomings. The intake system has very limited capabilities, since the fuel is combined with air not in the cylinders, but in the channels. Therefore, the motor has a weak torque and low power. In addition, 8 valves are considered insufficient for today's vehicles.
In general, this type of engine is only good for a low-speed family car. Apparently, therefore, car manufacturers have been increasingly abandoning it lately.
Important! Today, only a few companies use this type of motor in their vehicles. In addition, repairing it is quite expensive. This must be taken into account when choosing a car.
Although there are attempts to upgrade this engine. For example, in 2014 Skoda installed an improved engine of this type on the Yeti, designed specifically for the Russian segment. He received a power of 110 horsepower.
American developers are also engaged in modernization, but nevertheless, in the confrontation between power and reliability, manufacturers and motorists more often choose the former.
The period of increased interest in gasoline engines MPI (the abbreviation stands for Multi Point Injection) came at the end of the last century 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 idea of an automobile engine with multipoint injection was implemented by Volkswagen, which significantly contributed to the emergence of an effective alternative to carburetor engines in the person of MPI. 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 series Škoda Octavia, Volkswagen Polo, Volkswagen Golf 7, Škoda Yeti for Russian roads, etc. The most memorable representatives with MPI in recent years motors with a volume of 1.4 and 1.6 liters became.
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... It cannot be said that it is simpler than that of carburetor models, but in comparison with TSI engines equipped with injection 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 on our own.
- Moderate requests for the quality of fuels and lubricants. This is especially important for Russia, 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 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 fuel consumption... 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, German manufacturers also think so, having decided that the MPI engine would be the best option for the Russian version of the Škoda Yeti.
