Types of Diesel Injector

Understanding Diesel Injectors and Injection Systems

Although a diesel engine system may have several components, one tiny part keeps the engine humming. This tiny part is fuel injectors, which are an integral part of a vehicle’s fuel injection system.

Several companies have spent top dollars in R&D to optimize this tiny component since it has a significant impact on the performance of diesel engine vehicles.

Whether in cars, trucks, off-road vehicles, or heavy-duty vehicles, injectors play a critical role in defining engine performance in terms of fuel efficiency, emissions, and longevity.

In this post, we will explore the universe of diesel fuel injectors and systems, starting with the know-how of how diesel engines work and the role injectors play in the combustion process. 

How Diesel Engines Work?

Both gasoline and diesel fuel vehicles work on internal combustion technology. They differ in how the fuel is injected into the combustion chamber for the combustion process.

In Gasoline engines, the air-fuel mixture is ignited within the combustion chamber by a spark from the spark plug. 

Diesel Engine Combustion Chamber

As there are no spark plugs in diesel engines, combustion happens when fuel is introduced directly into the chamber during the compression stroke. In the compression stroke, the pressure and temperature of air inside the chamber are significantly higher enabling ignition of the air-fuel charge. 

The Role of Diesel Injectors

The diesel fuel injector’s job is to provide precise and metered quantities of atomized fuel exactly at the right time. It may sound simple, but there is a lot of technology that goes into this.

The most significant achievements attained in diesel engine advancements can be directly attributed to the advancements in injector technology. 

An injector has to ensure precise fuel delivery despite the high pressure and temperature inside the chamber. Injector pressure can reach up to 36,000 PSIG (atmospheric pressure is roughly 1 PSIG), and temperatures can reach 1000 degrees Fahrenheit.

High-Pressure Precision Injector

Due to injector technology advancements, its cost may represent as much as 30% of the total cost of the engine. 

The design and engineering of injectors heavily influence the performance of the engine itself. 

Fuel efficiency, noise characteristics, and emission levels are impacted by the fuel injector technology and design.

Decoding the Diesel Fuel Injection System:

To know how different types of diesel injectors work, it is important to understand the fuel injection system. Each component in the system along with injectors plays a unique role in ensuring fuel is injected with precision. Here are the components of a diesel engine:

CRDI Injector in Action

1. Nozzle: 

At the heart of every injector is the nozzle. The nozzle is a tiny part of the injector that atomizes the fuel into a fine mist of tiny droplets before it can be injected into the combustion chamber. Atomizing the fuel is critical for rapid and efficient combustion.

The nozzle is precision-engineered to ensure that the fuel spray pattern is consistent for even and complete combustion.

2. Needle valve

The needle valve, also known as the control valve, works in tandem with the nozzle. The needle valve regulates fuel flow by opening and closing the injector’s nozzle. This regulation is essential for precise timing and metering, allowing the engine to run efficiently across different operating conditions.

3. Solenoid

A solenoid is an electromagnetic coil within the injector that acts as a valve. The solenoid responds to electrical signals from the Electronic control unit (ECU), based on which it either opens or closes the injector. 

Think of ECU as a programmed chip that provides instructions to the key components of a vehicle, including injectors and fuel injection systems.

Solenoid enables the injector to deliver precise amounts of fuel at the right time, aiding an efficient combustion process.

4. High-Pressure Pump

As the name suggests, the function of the high-pressure pump is to generate a high force and pressurize the fuel so that it can overcome the high pressure inside the chamber and still inject the atomized fuel. There are mechanical pump systems and common rail diesel systems, each with its unique advantages.

5. Fuel Lines & Fuel Filters

Fuel lines are an intricate network of pipes and tubes that transport the fuel from the tank to the injector. Any flaw or damage to the fuel lines can lead to a drop in pressure affecting the performance of injectors.

Fuel filters remove contaminants from the fuel since contaminants can cause damage to precision components like injectors. Typically, filtration happens in several stages, starting from the tank or transfer pump, followed by primary and secondary stages of filtration.

Types of Diesel Injectors:

There are several fuel injector types, each with their unique advantages and limitations. Some fuel injector types are listed below:

  • Unit Injectors: These integrate the pump and nozzle into a single unit, offering space efficiency. However, they pose challenges in repair and maintenance due to their complexity.
  • Common Rail Injectors: Operating with a high-pressure fuel rail, these injectors enable precise fuel delivery at accurate timings across multiple injectors.
  • Hydraulically Actuated Injectors: Utilizing hydraulic pressure to operate the nozzle, these injectors are cost-effective and simpler than electronic variants but may compromise precision.
  • Piezoelectric Injectors: Harnessing piezoelectric crystals for nozzle control, they ensure meticulous fuel delivery and timing, albeit at a higher cost.

Common Rail Diesel Injection Circuit

Maintaining your fuel injectors:

As with any automobile component, regular and scheduled maintenance of injection systems and injectors is essential to achieve fuel efficiency, desired noise characteristics, and emission control. Here’s how you can maintain the injection systems:

  • Use high-quality fuel: Ensure your diesel fuel is free of contaminants even though you may have filters as part of the fuel injection system.
  • Replace fuel filters: Fuel filters come with a limited life defined by the manufacturer. Ensure filters are changed as per OEM recommendation. Clogged filters affect fuel flow and can damage costlier injectors.
  • Use an injector cleaner: Periodic cleaning of the injector using a recommended cleaner will ensure the removal of clogs and dirt from the injector
  • Have your injectors checked and professionally serviced: Regular inspection and service by professional mechanics can help identify problems beforehand

Maximizing Diesel Engine Performance with the Right Injectors:

Grasping the nuances of different types of diesel fuel injectors and injection systems empowers vehicle owners to appreciate their pivotal role in maintaining the robust performance of diesel engines. These small yet mighty injectors are the lifeline of your powerful diesel machine!

For diesel owners seeking expert injector services or quality components, look no further than Diesel Fuel Components Inc.

We specialize in comprehensive repair, rebuilding, and testing services for different types of diesel injectors, pumps, and other vital diesel engine parts.

If you’re shopping for new or rebuilt fuel injectors, contact Diesel Fuel Components Inc. or give us a call at (800) 252-6625

Keep your diesel powerhouse in prime condition with our professional support.