MDE Unit 5 Q4

A Bosch jerk type fuel injection pump is a positive displacement pump that uses a helical plunger to inject fuel into a diesel engine’s cylinders.  

1. Helix Fuel Injection Pump Explained – saVRee

How it works:

• Plunger: The heart of the pump, it has a helical groove machined into it.   1. Jerk-type or Plunger-type Fuel Injection Pump – Working and Animation – YouTube www.youtube.com
• Barrel: The plunger moves within a cylindrical barrel.   1. How Helix Fuel Pumps Work! (Jerk Piston Variable Injection Pump) – YouTube m.youtube.com
• Fuel supply: Fuel enters the barrel through a port.
• Fuel delivery: As the plunger rotates, the helical groove controls the amount of fuel delivered to the injector.   1. Jerk-type or Plunger-type Fuel Injection Pump – Working and Animation – YouTube www.youtube.com
• Injection timing: The timing of fuel injection is determined by the position of the plunger in relation to the fuel delivery port.   1. Jerk-type or Plunger-type Fuel Injection Pump – Working and Animation – YouTube www.youtube.com

Key components:

• Plunger: The main component responsible for pumping fuel.
• Barrel: Houses the plunger and provides a sealing environment.
• Helical groove: Determines the amount of fuel injected.   1. Jerk-type or Plunger-type Fuel Injection Pump – Working and Animation – YouTube www.youtube.com
• Control rack: Adjusts the plunger’s position to control fuel quantity and timing.   1. Helix Fuel Injection Pump Explained – saVRee www.savree.com
• Injector: Delivers fuel to the engine cylinder.   1. Helix Fuel Injection Pump Explained – saVRee www.savree.com

The Bosch jerk pump was widely used in diesel engines for many years due to its simplicity and reliability. However, it has been largely replaced by more advanced systems like common rail injection due to limitations in fuel injection precision and control.

The delivered quantity of fuel oil can be controlled through a combination of mechanical and electronic systems:

Mechanical Control:

• Plunger Stroke: In older pump designs, the length of the plunger stroke determined the amount of fuel injected. This was adjusted manually.
• Delivery Valve Lift: The height the delivery valve lifts affects the volume of fuel delivered.

Electronic Control:

• Fuel Pump Controller: Modern systems use electronic control units (ECUs) to precisely regulate fuel delivery.
• Solenoid Valves: These valves, controlled by the ECU, open and close to control fuel flow.
• Pressure Sensors: Monitors fuel pressure to ensure accurate delivery.   1. Fuel pressure sensors – EFI AUTOMOTIVE SERVICE www.efi-service.com
• Flow Meters: Measure the volume of fuel delivered.   1. Types of fuel flow meters – Navixy docs.navixy.com

Additional Control Measures:

• Governor: Regulates engine speed and indirectly controls fuel delivery.
• Fuel Rack: A mechanical linkage that adjusts fuel pump output based on engine load.

It’s important to note that modern diesel engines use electronic control systems for precise fuel delivery, ensuring optimal engine performance and efficiency.  

1. Diesel fuel systems – how they work – Perkins Engines

The delivery valve is a crucial component in a diesel fuel injection pump. Its primary functions are:  

1. Delivery valve | Dictionary | Kubota Engine Discovery

• Preventing Fuel Backflow: When the plunger in the injection pump retracts, it creates a vacuum. The delivery valve prevents fuel from flowing back into the pump, ensuring that the next injection cycle starts with a full chamber of fuel.   1. KR20060117567A – The delivery valve with back pressure function of fuel injection pump for diesel engine – Google Patents patents.google.com
• Maintaining High Pressure: By preventing backflow, the delivery valve helps maintain a high-pressure fuel supply, which is essential for proper atomization and injection.
• Controlling Injection Timing: In some pump designs, the delivery valve can also influence injection timing by controlling the pressure build-up in the fuel line.

In essence, the delivery valve plays a vital role in ensuring accurate, efficient, and consistent fuel delivery to the engine’s cylinders.