Get to know the Direct Injection System in Car Engines

Direct injection systems are often offered as an attraction by car manufacturers. Want to know more about direct injection technology?

Direct injection technology is related to combustion in the engine. This system is often found in diesel engines. However, there are also petrol engines that can use it.

Direct injection is very useful in improving engine performance. Therefore, many people use it. So, what is direct injection technology like?

Definition of Direct Injection

In general, direct injection is an injector/nozzle system that is placed directly at the top of the combustion chamber. Engines with a direct injection system have a crown-shaped cylinder head to increase turbulence during combustion.

This system is the opposite of indirect injection which does not place the injector in the combustion chamber. As a consequence, indirect injection presents another chamber in the combustion chamber called the swirl chamber. 

History of Direct Injection

Direct injection originated from the desire to provide fuel efficiency. In combustion, it is known that there is a less efficient process known as the camshaft overlap phenomenon.

In simple terms, camshaft overlap is the time when the intake and exhaust valves are open at the same time. This means that when the intake valve starts to open, at the same time, the exhaust valve does not close completely. This condition results in some of the incoming fuel being wasted so that the combustion process is less efficient.

How Direct Injection Works

The presence of direct injection is aimed at improving fuel processing efficiency. The way it works is by spraying fuel in the form of mist directly into the main combustion chamber which is between the cylinder head and the piston. The exact position is above the piston.

Thanks to that, no more fuel will be wasted when combustion occurs. The key is the presence of the injector in the combustion chamber. This allows fuel requirements to be programmed as accurately as possible, both in terms of the amount of fuel sprayed and the spraying time.

Direct injection will be more effective on engines that are equipped with turbos. The knocking symptoms that can occur can be eliminated because the turbo pressure can be made as high. 

However, this requires injector material that is resistant to engine compression. For this reason, a precise injector is needed, resistant to high pressure and temperature from combustion in the combustion chamber.

Direct Injection Characteristics

The main goal of direct injection is to achieve combustion efficiency. Not surprisingly, this is its main advantage compared to indirect injection. However, in more detail, here are the advantages and disadvantages of direct injection.

â— Advantages of Direct Injection

1. The engine is easier to start even in cold conditions.

2. Fuel consumption will be more economical.

3. Thermal efficiency is better due to the small combustion chamber.

â— Disadvantages of Direct Injection

1. The engine sounds rougher and noisier.

2. Susceptible to blockages in the injector because the injector hole is smaller.

3. Power tends to be smaller as a result of fuel efficiency.

4. There is minor turbulence at low speeds.

How Does It Compare With Indirect Injection?

When compared with indirect injection, direct injection is superior in efficient fuel consumption. This is considered interesting for some parties. In addition, high heat transfer provides its own advantages.

However, the risk of blockage in the injector is not felt in indirect injection. In addition, indirect injection does not require a high injection system. 

Even so, the level of turbulence in both is almost the same. In indirect injection, the level of turbulence remains high at various engine speeds.

Such are the ins and outs of direct injection in car engines. Are you interested in owning a vehicle that uses it?