Which is more fuel efficient, multi point EFI or direct injection?

Multi-point EFI.

Multi-point injection: In order to better control the mixture of each cylinder, a fuel injector is installed between the intake manifold and the intake valve of each cylinder, so that each cylinder has an independent injector.

Direct injection: direct injection in the cylinder, the fuel injector of this engine directly injects fuel into the cylinder, which avoids carbon deposition in the intake tract, and also controls the fuel consumption of each cylinder well, which is more fuel-efficient.

Precautions for multi-point EFI.

If the injector is installed in the original carburetor position, i.e. there is only one gasoline injection point for the entire engine, this is called single-point EFI. If the injector is installed on the intake pipe of each cylinder, i.e., the injection of gasoline is injected into the cylinder from multiple places (at least one injection point for each cylinder), this is called multi-point EFI.

Single-point EFI is the result of the transition from carburetor technology to EFI, because it is basically the same as the working principle of the carburetor, so there is no need to change the original carburetor engine block design, and the carburetor can be directly replaced with a set of computer-controlled equipment.

From the three aspects of carbon deposition, service life and oil requirements, multi-point EFI in automobile engines is better than direct injection.

In the process of rapid development of gasoline engine and diesel engine, the two technologies are actually borrowed from each other, and the use of in-cylinder direct injection technology is a major attempt by people, and in-cylinder direct injection technology is gradually replacing multi-point EFI. And the development of in-cylinder direct injection technology is also very rapid, major car companies are competing to study this technology, the effect is also quite significant, at present, Volkswagen in the in-cylinder direct injection technology is a relatively mature car company.

Multi-point EFI and direct injection have their own advantages. In general, multi-point EFI is to inject fuel into the intake pipe of each cylinder of the engine, and the fuel forms a mixture in the intake pipe, which is more efficient than single-point EFI, and can release greater power with the same displacement, but the disadvantage is that the requirements for the oil unit are relatively high. Relatively mature technology and wide range of applications.

Direct injection is one of the most popular technologies in recent years, and this set of technologies that was originally used in diesel engines is now widely used in gasoline engines. It is to inject fuel directly into the cylinder of the engine, and form a combustible mixture with air in the cylinder, which is more economical and environmentally friendly, and has obvious advantages. However, the requirements for the strength of the cylinder block and the fuel injector of the cooling system are very high, and they are now less used.

Compared with direct injection, multi-point EFI is more economical and more mature in terms of maintenance, but it is not as obvious as direct injection in terms of fuel, which will increase fuel consumption and cause unnecessary waste. Direct injection will be more accurate than multi-point EFI, better combustion, can save fuel and achieve greater horsepower, but direct injection is more demanding than multi-point EFI, and generally needs to be used with additives.

Advantages and disadvantages of multi-point EFI:

1. Advantages of multi-point EFI:

1. The combustion efficiency is high, and the same displacement can release greater power.

2. Sequential injection can be used, so the control of air-fuel ratio is more accurate than single-point injection, so the emission of multi-point injection engine is better and more economical and fuel-efficient.

Second, the disadvantages of multi-point EFI:

1. The requirements for oil products are relatively high, including engine oil.

2. The structure is relatively complex, so the cost is high.

Is it better to buy direct injection or EFI? Let's learn about the difference between in-cylinder direct injection and multi-point EFI.

The difference between multi-point EFI and in-cylinder direct injection:

1. In terms of oil products, the requirements for oil products for direct injection in the cylinder are higher than those for multi-point EFI, and the compression ratio is as high as 12.

2. In terms of cost and cost, because the components of direct injection in the cylinder are more complex than those of multi-point EFI, they are usually more expensive. That is to say, for the same car, the in-cylinder direct injection technology is more expensive than the multi-point EFI technology.

3. In terms of fuel consumption, the fuel consumption of direct injection in the cylinder will be much lower than that of multi-point EFI.

4. In terms of power performance, the power and torque of in-cylinder direct injection are increased by 10% compared with that of general engines of the same displacement.

5. At the technical level, multi-point EFI technology is more mature, while in-cylinder direct injection is a new type of more advanced fuel injection technology.

6. In terms of later maintenance, the structure of multi-point EFI is simple, and the maintenance and reliability are better than those of direct injection in the cylinder.

EFI is an electronically controlled way to inject fuel into the intake pipe and mix with air, and then the air-gas mixture is sucked into the cylinder by the suction stroke of the engine.

Direct injection in the cylinder is that the fuel injector is moved from the intake manifold to the inside of the cylinder, so the amount of oil and gas in the cylinder will not be affected by the opening and closing of the intake valve, but the computer will automatically determine the timing and amount of fuel injection.

Since the mixing space and time of oil and gas are quite short, the in-cylinder direct injection system must rely on high pressure to press the fuel from the injector into the cylinder to achieve a high degree of atomization.

What are the advantages and disadvantages of multi-point EFI and in-cylinder direct injection? The difference is quite big, don't choose the wrong car when buying a car.

In terms of technology, of course, it is the engine with direct injection. At present, turbocharging and in-cylinder direct injection are the two most effective technologies for engine power improvement and fuel consumption control.

Direct injection is better.

Multi-point EFI and direct injection are both gasoline electronic injection engines.

It's just that the injection control is completely different, and multi-point injection is a normal type of control, and the oil and gas are mixed outside the cylinder and enter the combustion chamber.

Direct fuel injection is a new technology in recent years, which is to inject fuel directly into the cylinder to form a mixture in the combustion chamber. This results in more precise fuel control and less power loss. However, the requirements for oil products are high, and they generally need to be used with additives.

The direct injection engine in the cylinder is good.

Direct injection is the latest automotive engine technology available today. Effectively improve power and reduce fuel consumption. Multi-point EFI is an upgrade in the original technology.

Multi-point EFI is also an effective way to improve power and reduce fuel consumption. However, the effect of direct injection in the cylinder is not as obvious. It's just that more fuel injection can make the gasoline burn more fully, of course, the power is stronger, and the fuel consumption is lower.

With direct injection, the fuel enters the cylinder as a fine droplet mist instead of steam. This means that when the fuel droplets absorb heat and become combustible vapors, they actually cool the engine's cylinders. This cooling reduces the engine's need for octane, so its compression ratio can be increased.

And, just like diesel, using a higher compression ratio can improve fuel efficiency.

Each has its advantages.

1. Multi-point EFI

The advantage of multi-point EFI is that sequential injection can be used, and the fuel quality requirements are relatively low, because the oil, gas and air can be fully mixed inside the intake manifold, which is more conducive to full combustion in the combustion chamber; At the same time, due to the oil-gas mixing in the intake manifold, the multi-point EF cylinder has less carbon deposit, extending the life of the cylinder.

The disadvantage of multi-point EFI is high fuel consumption, due to the mixing of oil and gas in the intake manifold, there is inevitably a loss after entering the cylinder, which increases fuel consumption; At the same time, due to the different positions of oil and gas mixing, the density of multi-point EFI oil and gas mixing is smaller than that of direct injection in the cylinder, resulting in relatively weak engine power.

2. Direct injection in the cylinder

Direct injection is a new type of fuel injection technology. Fuel is injected directly into the combustion chamber of the cylinder at high pressure. Instead of placing the fuel injector in front of the intake valve, it is no longer the air-gas mixture that reaches the intake valve, but pure air.

In this way, the engine with direct injection in the cylinder can know the amount of air entering the cylinder according to the time when the intake valve is opened, and then spray the corresponding amount of fuel according to the working needs of the vehicle at that time.

The advantages of in-cylinder direct injection are low fuel consumption, high liter power, and a compression ratio of up to 12, which increases power and torque by 10% compared with ordinary engines of the same displacement. At the same time, the high-pressure fuel injected into the combustion chamber of a direct-injection engine enters in the form of a fine mist, which absorbs heat when it evaporates, cooling the cylinders and thus reducing emissions.

The disadvantage of direct injection in the cylinder is that the components are complex and usually expensive. At the same time, the technical requirements are relatively high, and the technical difficulty of the in-cylinder direct injection engine is the realization of "layered combustion".

Vehicle fuel consumption has nothing to do with EFI and direct injection.

Although direct injection engines are theoretically more fuel efficient than EFI engines, direct injection engines have the disadvantage of being prone to carbon deposits, which are more difficult to remove once carbon deposits are generated. As a result, the intake efficiency decreases and the power decreases. Therefore, at a practical level, the opposite conclusion may be reached.

The fuel consumption of the car is related to many factors, direct injection engine and EFI engine are just one of many factors, as far as engine technology is concerned, there will be no obvious difference in fuel consumption in long-term use. Developing good driving habits is the most important factor in determining fuel consumption.

The above content reference: Phoenix - EFI and direct injection engines Which is more fuel-efficient?

The above content reference: Phoenix Network - EFI or direct injection, which is more fuel-efficient?

Multi-point EFI.

Multi-point EFI combustion efficiency is high, the same displacement can release greater power, sequential injection can be used, so the control of air-fuel ratio is more accurate than single-point injection, so the emission of multi-point injection engine is better, more economical and fuel-efficient.

The direct injection engine high-pressure fuel is injected into the combustion chamber, which is entered in the form of a fine mist, which absorbs heat when evaporating, cools the cylinder, can burn lean, can improve the combustion efficiency by 20%, and the air intake is more than that of the traditional engine, and the combustion is sufficient, reducing the generation of C0.

Multi-point EFI function.

There are many uncontrollable factors that cause gasoline and air to mix in the intake manifold, so the gasoline and air in engines using multi-point EFI systems cannot be fully mixed. There are many naturally aspirated engines and turbocharged engines that use direct injection technology, and the injector of the direct injection engine is in the engine, and the injection pressure of this engine is higher.

The higher the injection pressure, the more complete atomization of gasoline, so that the gasoline can be mixed with the air well. Gasoline is well mixed with air to increase power and reduce fuel consumption. Generally, engines equipped with in-cylinder direct injection technology have better fuel economy than multi-point EFI engines, and the power is also stronger than multi-point EFI engines.