Diesel engines are the backbone of the transportation industry, powering everything from trucks and cars to heavy-duty and off-highway vehicles.
The fuel injection system is crucial for your diesel vehicle’s performance.
It ensures that fuel is efficiently delivered from the tank to the combustion chambers without losing volume or pressure.
The diesel fuel injection pump at the heart of this system pumps diesel into the engine at high pressure and the right volume.
In this article, we’ll guide you through the types of diesel fuel injection pumps, their functions, common problems, and symptoms to watch out for.
Diesel Engine Basics
Diesel engines are called Compression Ignition engines (CI) since they take in the air during the suction stroke and compress it to a high pressure of 400 to 600 psi.
At these pressures, the air temperature rises to a higher level. Currently, high-pressure diesel fuel is injected into the engine via fuel injectors.
What Is a Diesel Injection Pump?
As the name suggests, an injection pump is an automobile component to pump fuel at high pressure.
Modern-day diesel engines use the Direct Injection (DI) method. In this method, pressurized fuel is directly injected into the engine chambers via fuel injectors.
Fuel injectors ensure fuel delivery into the combustion chambers by controlling the quantity and timing of injection.
It also atomizes the fuel into tiny particles to enhance combustion.
Common Types of Fuel Injection Pumps in Diesel Engines
- Individual Inline Fuel Injection Pump or Unit Type Pump
- Distributor (rotary) Injection Pump
- High-Pressure Common Rail Pump or CRDi
Individual Inline Fuel Injection Pump:
Inline pumps are preferred for heavy-duty diesel engines since these can generate a high pressure of up to 1800 bar fuel injection.
The inline pump unit has plungers that pressurize the fuel, which is injected into the chambers via fuel injectors.
The number of plungers and injectors will exactly match the number of cylinders. The plunger is operated by a Camshaft, which derives its power from the engine crankshaft.
The force generated by the camshaft directs the plunger to pump the fuel at a higher pressure. The timing of contacting the plunger is determined by the camshaft design.
The crankshaft’s rotations per minute (RPM) determine the camshaft’s speed.
Pros:
- Single and more compact assembly
- Injection pressure is higher
- Excellent for heavy-duty vehicles
- Combustion is more efficient
- Less noisy
- Lower emissions
Cons:
- Better alternatives are available for light-duty vehicles
Distributor Or Rotary Type Injection Pump:
It is small and used for limited-space applications. A plunger is available for each injector and cylinder in individual inline injection pumps.
On the other hand, in distributor-type pumps, one plunger will generate enough force to pump the fuel through all the injectors. Due to this, the pressure generated by the pump is lower than an individual inline injection pump.
Pros:
- It is ideal for limited-space applications due to its small size
- Its more straightforward design reduces manufacturing and maintenance costs
- Fewer components make repairs less complex
Cons:
- Generates lower fuel pressure, which may affect engine performance
- Not suitable for high-performance or heavy-duty engines
- Less adaptable to engines requiring high fuel injection precision
High-Pressure Common Rail Pump:
All modern-day diesel engines use this pump. The technology behind this pump is quite advanced since unique materials are used to ensure that the components can withstand higher pressure.
The pressure generated in the pump can be as high as 2700 bar.
Unlike the individual inline pumps, the system, in this case, consists of a single high-pressure pump connected to a common rail manifold, which is, in turn, connected to multiple electronic fuel injectors.
The engine’s electronic control unit, or ECU, controls the electronic fuel injectors.
Think of ECU as a microcomputer that guides the performance of fuel injectors. Once the pump pressures the fuel, it is transported to the common rail manifold system through pressure-resistant steel tubes.
The pressurized diesel fuel is distributed to the various cylinders through individual cylinder-mounted electronic fuel injectors.
The quantity and timing of fuel injected by the fuel injectors are determined by solenoid-operated valves built within them. All the components of the system are designed using advanced technology and materials.
Pros:
- Great for all types of diesel vehicles
- Combustion is very efficient
- Fuel delivery is more precise
- Meets the latest EPA emission standards
- Quietest engine
Cons:
None significant.
Bad Fuel Pump Symptoms:
- Engine Splutters: This occurs when the fuel injection pump in a diesel engine cannot deliver the required volume at the correct pressure setting. One can notice the engine spluttering noise while accelerating the engine.
- Whining Noise: The noise is made by a faulty diesel injection pump and originates from the pump itself. Sometimes, it is caused by insufficient fuel in the tank.
- Difficult to Start: This happens when the fuel pump cannot produce the required pressure to pass the fuel to the injectors.
- High Exhaust Emissions: This happens when the diesel injection pump pumps a higher volume of fuel than what is needed for operation. This results in improper combustion, leading to higher emissions and poor fuel economy.
Conclusion:
Every diesel-powered vehicle needs a reliable fuel injection system for top performance.
Different types of diesel fuel injection pumps serve varying needs. Still, pump issues can lead to problems such as poor fuel efficiency, engine noise, weak acceleration, and failure to meet emission standards.
You don’t need to be a fuel injector expert to handle these problems.
Diesel Components Inc. specializes in Diesel injection pump repair and diagnosis to ensure your vehicle runs at its best. Our team of experts has been serving North America since 1977, providing top-quality diesel fuel injection pump repairs and rebuilds. Whether you’re dealing with injector pump issues or need routine maintenance, we’re here to help.
Contact us today to learn more about our services and how we can keep your diesel engine in peak condition. Call us at (800) 252-6625, (952) 890-2885, or email us at sales@dieselcomponentsinc.com.
