GDI engines: the pros and cons of GDI engines, what is it
Gasoline Direct Injection, or more commonly known as GDI, is an injection system for gasoline engines with direct fuel injection. The design of the device goes under different acronyms from manufacturer to manufacturer. Mitsubishi (as well as KIA and Hyndai) gave the name GDI, Volkswagen – FSI, Ford – Ecoboost, Toyota – 4D, Mercedes, BMW and some others hide the term “direct injection” in the engine index. With these feeding systems, fuel injectors are inserted into the cylinder head and atomization occurs immediately into each combustion chamber, bypassing the intake manifold and intake valves. Fuel is fed at high pressure into the cylinder, which is assisted by a high-pressure fuel pump (HPP).
Differences and peculiarities of GDI engines with direct fuel injection
In fact we have a kind of symbiosis of diesel and gasoline engines in one. GDI inherited the injection system and HPF from the diesel, fuel type and spark plugs from the gasoline. The ancestor of GDI engines was Mitsubishi when the Mitsubishi Galant 1.8 GDI was introduced in 1995. Today’s direct injection engine. It is a complex system of mechanisms and electronic units in character and sounds in operation reminiscent of a diesel.
The direct injection engine appeared to the world much earlier. In the 1950s, such engines were used by Daimler-Benz in their racing cars, later in civilian cars, and in aviation they were present as early as the early 1940s.
The differences (varieties) of GDI engines. Brands of cars which use GDI
The prerequisites for the creation and mass transition of the majority of leading automakers to GDI-like injection systems were quite predictable. Environmental regulations requiring improved exhaust systems, as well as the global challenge of creating fuel efficient engines.
The GDI engines implemented several types of fuel-air mixture blending. This made it possible to meet the objectives of fuel economy, more complete combustion of the mixture and further increase power. The engine as a whole is made possible by an advanced direct injection system, in which the electronic stuffing plays an important role. The control unit reacts to the slightest changes in the car’s behavior through sensors scattered throughout the system, and adjusts the fuel system to the necessary requirements of the driver.
Advantages (pros) of GDI engines
- A special feature of direct injection engines is the ability to work in several types of mixture formation. This is a definite plus, since the variety in this type of procedure gives the maximum fuel efficiency. If the GDI system works properly, it saves fuel by running in ultra lean mixture mode, without any loss of output.
- GDI engines have a higher compression ratio of the air-fuel mixture. This helps to avoid glow ignition and detonation, and thus increases service life.
- The positive aspects of the GDI direct injection engine also include a significant reduction in carbon dioxide and other pollutants. This is achieved through multi-layer mixture formation, which ensures a more complete combustion of the mixture, which additionally affects the engine power.
The GDI system results in several types of mixture formation:
- stoichiometric homogeneous;
This variety makes the engine more economical, ensures better mixture formation quality, complete combustion, increase in power and reduction of harmful emissions.
Disadvantages (disadvantages) of GDI engines
The description of GDI engines would not be complete without mentioning the negative aspects of their operation.
- The main disadvantage is the complexity of the fuel intake and delivery system. With this injection option, the GDI engine becomes extremely sensitive to the quality of the fuel used. As a result, the problem of corked injectors becomes an issue for the driver. It will cause loss of power and increased fuel consumption.
- The disadvantages also include the complexity and cost of maintenance and replacement of parts and units of the fuel system, so an important point is to monitor the condition of the fuel system of the car.
- Additionally, GDI and other direct injection engines emit higher amounts of particulate matter than MPI (manifold injection) engines, forcing the use of particulate filters in the latest engine generations.
- Also, GDI engines tend to create soot in the intake manifold and on the valves at mileage in excess of 100,000 miles, forcing owners to call for service for cleaning.
The GDI engine is more expensive to maintain, but the performance characteristics override this disadvantage. Moreover, there are means to help increase the service life of capricious parts and assemblies.
Troubleshooting for GDI Engines
Prevention is a simple solution for the owner of a car with a GDI engine direct injection system or similar systems. As we wrote above, fuel quality will play a major role. It is clear that without laboratory tests it is impossible to judge the quality of this component, so fuel additives can help as a preventive measure and protect the fuel system from emerging problems.
Liqui Moly, one of the world leaders in the production of automotive chemicals, recommends using Langzeit Injection Reiniger, part number 7568, to maintain the necessary level of lubricating and cleaning additives in the fuel used. Consistent use of the additive will significantly reduce the risk of fuel related breakdowns. Additive packages that increase the lubricity of the fuel will reliably protect the fuel system from rapid deterioration.
For the treatment and prevention of fouled injectors, there is also the reliable Direkt Injection Reiniger, part no. 7554. It replaces bench cleaning of injectors, works on soot and tar. An important point is that Liqui Moly fuel additives start working in the system when the temperature rises, that is where cleaning is needed most often, while in the tank it is only mixed with fuel.
Is it worth buying cars with GDI engines
With the proper approach and timely maintenance, the owner of a car with the GDI system gets a comfortable car with high traction, power and good fuel economy. And as the sales of such cars show, they will be on the road more often.
GDI engines were one of the pioneers of direct fuel injection systems. With their obvious advantages, these engines require special preventive maintenance. First and foremost is maintenance of the injectors. The easiest way is to use fuel additives. By taking preventive care of the fuel system in cars with GDI engines, the car owner can extend its life and enjoy the increased power and dynamics.
Automakers do not stand still, the development and improvement of engines with direct injection systems continues. Cars with T-GDI engines have already been introduced, but that’s another story.
GDI engines – features, advantages and disadvantages
GDI engines have recently become widespread in the automotive industry. The abbreviation translates as Gasoline Direct Injection. Such engines have a fuel injection system. The design of the same device may be designated by different manufacturers with different symbols.
The main peculiarity of GDI engines with direct fuel injection is the possibility to use several types of gasoline mixture.
Mitsubishi gives the name GDI, Volkswagen – FSI, Ford – Ecoboost, Toyota – 4D. With this delivery system, the fuel injectors are inserted into the cylinder head, and the spray itself goes into each combustion chamber without going through the intake manifold and valve. Fuel is fed into the system at high pressure, for which the fuel pump is responsible.
In fact, the GDI direct injection engine is a symbiosis of a diesel engine and a gasoline engine. The GDI engine gets its injection system and high-pressure fuel pump from the diesel engine, and the fuel type and spark plugs from the gasoline engine. The first company to equip cars with such engines was Mitsubishi. In 1995, the Mitsubishi Galant 1.8 GDI was introduced to the world.
GDI engines are prone to fouling in the intake manifold and on the valves when the car’s mileage exceeds 100,000 km
Advantages . The main feature of GDI engines with direct fuel injection is the ability to handle several types of mixture. This is an undeniable plus in the automotive industry, as the variety and wide choice ensures better fuel efficiency. If the direct injection system is in good working order, good fuel economy can be achieved without any loss of power.
Another plus is that GDI engines have an increased compression ratio of the fuel mixture. This automatically gets rid of the unit from glow ignition and detonation, which has a positive effect on service life. Another positive aspect is the reduction of carbon dioxide and other harmful elements. This phenomenon is achieved with the help of multi-layer mixing. Note that the GDI system can provide several types of mixture formation in the process – layer-by-layer, homogeneous and stoichiometric homogeneous.
The most urgent problem in a used car is nozzles clogging.
Disadvantages . The main disadvantage is related to the fact that the fuel intake and delivery system has a complex design. The engine with this type of injection is very sensitive to the quality of the fuel used. As a result, the most pressing problem in a car with mileage is the coking of the injectors. This leads to a loss of power and increased fuel consumption. The second disadvantage is the difficulty of maintenance and the high cost of repairs.
In addition, GDI engines are prone to fouling in the intake manifold and on the valves when the car’s mileage exceeds 100,000 km. Because of this, car owners are forced to go to the service for cleaning. The GDI motor is more expensive to service, but the performance parameters override all the disadvantages. In addition, there are tools on the market that allow you to extend the life of the power unit.
If you want to buy a car with this motor, you should think about maintenance beforehand. Preventive maintenance will be much cheaper than repairs. Cleaning and lubricating additives should be used in the fuel used. If you apply products on a regular basis, you can avoid contamination of the system.
Bottom line . GDI direct injection engines are a hybrid of a gasoline and diesel engine. They have their advantages if properly serviced.