Common Rail Fuel Pressure Reduction During Engine Shutdown
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Solution Overview
Problem
Common Rail diesel engine systems experience prolonged high pressure in the accumulator tank after shutdown, posing a risk of uncontrolled fuel spurt during servicing or repair, necessitating cautious handling.
Innovation Solution
A method and arrangement that execute a second switch-off process by stopping fuel supply to the accumulator tank while activating injection means to run the engine until fuel pressure decreases to a safe level, allowing for safe servicing or repair without uncontrolled fuel release, utilizing a control unit and diagnostic tool to initiate and manage this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the first switch-off process is used to quickly shut down the combustion engine, then the switching off time is reduced, but the fuel pressure in the accumulator tank remains at a high level posing safety risks during servicing
Solution Approach 1:
The control unit executes preliminary actions by automatically initiating a second switch-off process after the engine stops, which actively reduces fuel pressure in the accumulator tank through controlled fuel injection before servicing begins. This preliminary pressure reduction eliminates the safety hazard without requiring manual intervention or extending the initial shutdown time.
Solution Approach 2:
The system converts the harmful high fuel pressure into a beneficial condition by using the remaining fuel in the accumulator tank to perform useful work during the second switch-off process. The fuel is injected into the combustion chamber to continue driving the engine for a brief period, which naturally consumes the fuel and reduces pressure safely, transforming a hazard into a controlled operational phase.
2Object-affected harmful factors
If the second switch-off process is executed to reduce fuel pressure safely, then the safety during servicing is improved, but the switching off time increases due to the extended operation period
Solution Approach 1:
The system dynamically adapts the second switch-off process duration based on real-time fuel pressure measurements. The control unit continuously monitors the accumulator tank pressure and automatically terminates the extended operation once the pressure reaches a predetermined safe level, optimizing the time extension to the minimum necessary for safety without unnecessary delays.
Solution Approach 2:
The pressure sensor provides continuous feedback to the control unit regarding the fuel pressure in the accumulator tank. This feedback loop enables the control unit to make real-time decisions about when to terminate the second switch-off process, ensuring the pressure is reduced to a safe level while minimizing the extended operation time through precise, data-driven control.
3Device complexity
If manual pressure reduction methods are used during servicing, then the equipment complexity is reduced, but the ease of operation deteriorates due to the need for cautious handling procedures
Solution Approach 1:
The fuel injection system performs self-service by automatically executing the pressure reduction function through its existing components. The control unit and pressure sensor work together to autonomously manage the second switch-off process, eliminating the need for separate manual pressure reduction equipment while simultaneously improving ease of operation by removing the need for cautious manual handling procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively reduces the risk of uncontrolled fuel spurt and facilitates safe servicing by ensuring the fuel pressure in the accumulator tank is decreased to a safe level, preventing accidents and unnecessary contamination during maintenance.
Implementation Method 1
an accumulator tank adapted to receive and store fuel from the high-pressure pump at high pressure
Implementation Method 2
a high-pressure pump adapted to pressurise the fuel in the fuel line
Data Source
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AI summary
The present invention relates to an arrangement and a method for switching off an engine (1) with a fuel injection system which comprises having injection means (8) for injecting the pressurised fuel in an accumulator tank into the respective combustion spaces of the engine, and a control unit (9) for executing a first switch-off process (A) of the engine which results in fiiel at an overpressure remaining in the tank after the engine has stopped. The method comprises the step of executing a second switch-off process (B) by stopping the supply of fuel to the tank while the injection means are activated so that the engine runs for a final period until a fuel pressure in the tank has decreased to a predetermined pressure level or the fuel in the tank is consumed to such an extent that no overpressure remains in the tank.