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 more than a year. Probably also those who are interested in technology in general and the automotive industry in particular. But at one time such an engine was a huge step forward: it was he who replaced the carburetor.
Among Volkswagen engines, this is the oldest development of those that were still in use until recently. True, the MPI engine was installed in recent years mainly on Skoda models. The last signs were the Skoda Octavia of the second series; on the third, more appropriate FSI or TSI were already installed. And yet, MPI is still considered to be the most reliable, practical and trouble-free among all injection engines.
MPI engine: what it is is quite simple to explain. After all, it is based on a commonly used injector, with only some features and limitations.
Device
The abbreviation stands for Multi Point Injection, i.e. multi-point injection. The engine is a gasoline unit, by definition not turbocharged, in which point injection is distributed over the cylinders. One injector is attached to each cylinder, which provides a metered supply of fuel under pressure through a dedicated intake port.
The design does not provide for a fuel rail, as fuel injection is implemented on TSI series engines. There is also no direct injection directly into the cylinders, as is done in TFSI or FSI engines. Due to the design features, the MPI motor had an ignition advance 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, this is MerCruiser, which stabilizes the functioning of the engine thanks to the developed system for releasing gas-air plugs.
The Germans supply the MPI engine with a well-thought-out system that controls the hydraulic drive, a clutch with a built-in grease fitting. And the engineering solution for differentiating the engine can be considered especially successful: the design is based on rubber mounts that automatically adjust to the rhythm and speed of movement, engine speed and uneven surfaces.
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 MPI power, engines were produced at 1.4 liters with 80 horses and 1.6 with 105.
Advantages
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 him (and not only from alternative manufacturers, but also for original Volkswagen models). The structure is extremely durable. If you deal with German cars with such an engine, then the manufacturer guarantees a repair-free mileage of 300,000 - if you are not too lazy to change filters and oil on time.
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Flaws
They are due precisely to the design features of the engine. Namely: the fuel is combined with air in the channels, and not directly in the cylinders. Therefore, the possibilities 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 are no longer enough. We can say that this is a family and leisurely 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.
MPI engines are gradually becoming a thing of the past, so you will rarely meet a car enthusiast who understands what they are talking 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 motor 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 the fact that it tolerates the poor quality of domestic fuel well.
Did you know? The abbreviation MPI comes from the term Multi Point Injection, which means multi-point fuel injection. The motor was actively used at the Volkswagen concern. Gradually, it was introduced at a subsidiary of Skoda. The motors were 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 implies 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 layered injection: Twincharged Stratified Injection. But recently, the abbreviation TFSI has become increasingly used, in which the additional letter F means Fuel - fuel.
You can often find another abbreviated name for the engine - MPI DOHC, which is easy to understand if you know that the term DOHC refers to engines that have 2 camshafts and 4 valves in the cylinder head.
Principle of operation
The MPI fuel injection system delivers fuel from multiple points at the same time. Each cylinder has its own injector, and fuel is supplied through a special exhaust channel. But what distinguishes the MPI engine from the TSI, which is also equipped with a multi-point fuel supply, is no boost.
The fuel mixture is supplied to the cylinders not with the help of turbochargers, but with the help of a gasoline pump. It pumps gasoline into a special intake manifold at a pressure of three atmospheres, where it mixes with air and is also sucked into the cylinder through the intake valve under pressure.
Schematically, the operation of the engine looks like this:- The fuel pump pumps fuel from the tank to the injector.
- From the electronic injection control unit, a signal is sent to the injector, which passes fuel into a special channel.
- The mixture is sent to the combustion chamber.
The hydraulic drive control system consists of a clutch with a grease fitting and a system that limits the trims. It includes rubber mounts that can independently adjust to the operating mode of the engine, 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 are MPI 1.4 engines with 80 horsepower, as well as 1.6 with 105 horsepower. But automakers are gradually abandoning them anyway. The only ones who still use engines of this type are Dodge and Skoda.
Advantages
The engine has several advantages, the main of which is - the 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 design is very durable. In most cases, you can drive up to 300 thousand km without engine repair. Of course, if you maintain it properly: change the oil and filters on time.
Flaws
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 cars.
In general, this type of engine is only good for a low-speed family car. Apparently, therefore, car manufacturers have been increasingly refusing it recently.
Important! Today, only a few companies use this type of motor in their vehicles. In addition, its repair is quite expensive. This must be taken into account when choosing a car.
Although there are attempts to modernize 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.
Modernization is also carried out by American developers, but still, in the confrontation between power and reliability, manufacturers and motorists often choose the first.
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:
- First, fuel from the gas tank is pumped into the injector;
- After receiving a certain signal from the electronic control unit, the injector sends fuel to a special channel;
- 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.
Now it is a thing of the past, and not even all motorists remember it and can give at least an approximate definition of this unit. The appearance of this engine made it possible to abandon carburetor units. If we consider the Volkswagen engine line, then it is MPI that is the oldest development, the use of which has dragged on for such a long period. For the past few years, such units have been installed only on Skoda. Despite the appearance and wide, MPI is still considered the most reliable, trouble-free and practical in the line of injection units.
Features of the MPI engine.How does the abbreviation stand for
As we have already learned, we have an injection engine in front of us. Its operation is based on a multi-point type system. This feature gave the name to the unit, because the abbreviation MPI stands for Multi Point Injection. The Volkswagen concern is considered the developer of such a mechanism. Each cylinder has its own separate nozzle or injector.
The reason for the rejection of such a mechanism is its inconsistency with modern environmental requirements and the economic foundations on which modern society lives.
We figured out a little what an MPI engine is, but we still have to learn about the principle of operation, consider the advantages and disadvantages of this unit.
The principle of operation of the MPI power plant
The unit works according to the following principle:
- each cylinder is equipped with a separate injector;
- the flow of fuel mass is carried out immediately through several points;
- for supplying fuel through a gasoline pump there is a separate outlet channel;
- the fuel mass enters the intake manifold, while the pressure is at the level of 3 atmospheres;
- inside the manifold, the fuel is mixed with air, resulting in a special working mixture;
- This mixture passes through the inlet valve under pressure into the cylinder.
In these power plants there is an ignition advance. This means that in MPI the gas pedal is sensitive. This point should be taken into account by drivers who own cars with this type of power plant.
Advantages and disadvantages of MPI engines
Such units are far from ideal. They are characterized by positive and negative points. It's time to get to know them.
Advantages
The list of positive characteristics consists of the following items:
- simplicity of design provides easy repair and affordable maintenance;
- the admissibility of using 92 gasoline, this applies to both alternative and original models;
- maximum strength;
- high mileage with timely replacement of filters and oil.
The advantages are impressive, but they fade somewhat after studying the negative points.
Flaws
Negative characteristics are associated with design features. The list of shortcomings consists of the following items:
- the limitations of the fuel system are associated with the mixing of fuel and air not in the cylinders, but in the channels;
- weak torque and insufficient power emerge from the previous point;
- lack of special dynamics, drive and throttle response;
- 8 valves is not enough.
Early motorists wrote off the MPI. Skoda, when developing Yeti, which is intended for a Russian user, did not use a 1.2 turbocharged engine. Instead, the company installed an updated and even modified at some points 1.6 MPI for 110 “horses”. This unit is more related to TSI, but in its design and direct fuel injection.
One of the very popular engines that is installed on Volkswagen cars (currently SKODA is mostly equipped with it) is the MPI engine. Of course, it should be noted that this engine model is the oldest of the entire range of Volkswagen power units available, but we must give it its due, since MPI is the most practical and trouble-free of the entire line of power units, we read about the TSI engine.
Principle of operation.
This type of engine (in translation means multi-point injection) is a non-turbo engine that runs on gasoline and uses a multi-point distributed injection of fuel passing through the injector during its operation. MPI does not have a fuel rail, like many other types of engine, also does not have fuel injection into the cylinders themselves, only one injector is used separately for each cylinder.
This power unit has its own individual fuel injection structure. It can be roughly expressed as follows: there is one injector per individual cylinder, fuel is supplied through a specially made exhaust channel.
Also, MPI is endowed with the function of advancing the ignition process, due to which an increased indicator of sensitivity of the gas pedal is provided. The structure of this engine is unthinkable without cooling the fuel mixture (MerCruiser) with water, thereby achieving the required temperature of the fuel mixture. This helps to increase the stability indicators during engine operation many times over by getting rid of gas plugs (air).
This type of power units is also equipped with a new system that independently controls the hydraulic drive. There is a clutch with a grease fitting, a system that allows you to limit trims with memory (its basis is rubber mounts that independently adjust to the operating mode of the motor, thereby significantly reducing vibration and noise during operation).
The engine has a system of eight valves (two valves per cylinder) and a camshaft. The most prominent representatives in this engine family are considered to be the MPI 1.6 engine (105 hp) and the MPI 1.4 liter engine (80 hp).
Advantages.
The engine is completely unpretentious and can work well on ninety-second gasoline. According to its manufacturer, the design of the MPI engine is very durable, and its minimum mileage without any repair will be three hundred thousand kilometers, of course, provided that filters and oil are replaced in a timely manner.
And due to the simple MPI device, it is easy and cheap to repair.
Flaws.
Due to the fact that the process of mixing the fuel takes place in the exhaust special channels (before it enters the cylinders), such engines have a limited capacity of the intake system. And this, in turn, affects the performance of torque and power. Also, they cannot be called daring and “dynamic”. The presence of an 8-valve system with a timing package also indicates a significant loss in power. In general, they are designed for slow, unhurried driving.
Due to its structure, which is relatively old, MPI is slowly being phased out of mass production. The most recent car models equipped with these power units were the second generation Scoda Octavia. At the same time, the third generation has already been equipped with more advanced and modern engines.
