Fuel Return Line Pressure Accumulator for Stop-Start Engines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In internal combustion engines with automatic stop-start systems, the pressure in the common rail diesel engine drops rapidly due to leakage after shutdown, requiring rapid pressure buildup for efficient restart, which is challenging with existing systems that rely on over-dimensioned high-pressure pumps and additional accumulators.
Innovation Solution
A fuel injection system utilizing a fuel return line with a control element system that discharges excess fuel pressure to the tank when a threshold is reached and prevents further pressure loss, allowing the return line to act as a dual-function fuel pressure accumulator, enabling rapid pressure recovery during engine restart.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is equipped with an automatic stop-start system, then fuel consumption is reduced, but the pressure in the common rail drops rapidly after shutdown requiring rapid pressure buildup for restart
Solution Approach 1:
The fuel return line is pre-configured with a control element system that can rapidly close to trap pressure in the return line before engine restart. This preliminary preparation of the pressure accumulation mechanism allows for rapid pressure recovery without requiring additional accumulators or over-dimensioned pumps.
Solution Approach 2:
The fuel return line serves as an intermediary pressure storage mechanism between the common rail and the fuel tank. By using the return line as a pressure accumulator with the control element system, the patent creates a buffer that mediates between the high-pressure rail and the low-pressure tank, enabling rapid pressure recovery during stop-start operation.
2Speed
If over-dimensioned high-pressure pumps or additional accumulators are used to maintain pressure, then rapid pressure buildup is achieved, but device complexity and space requirements increase
Solution Approach 1:
The fuel return line is designed to perform dual functions: returning excess fuel to the tank during normal operation and serving as a pressure accumulator during stop-start sequences. The control element system enables the return line to switch between these functions, eliminating the need for separate accumulator components and reducing overall system complexity.
Solution Approach 2:
The patent merges the fuel return function and pressure accumulation function into a single integrated system. By combining these functions in the fuel return line with the control element system, the patent reduces the number of separate components needed, thereby simplifying the overall fuel injection system while maintaining rapid pressure buildup capability.
3Stability of the object's composition
If additional fuel accumulators are added to the system, then pressure stability is improved, but the system requires more space and additional components
Solution Approach 1:
The fuel return line is designed to perform dual functions: returning excess fuel to the tank during normal operation and serving as a pressure accumulator during stop-start sequences. The control element system enables the return line to switch between these functions, eliminating the need for separate accumulator components and reducing overall system complexity.
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
This solution allows for rapid pressure buildup in the rail system without additional components, optimizing space and efficiency by using the fuel return line as a pressure accumulator, ensuring quick engine restarts and improved fuel management.
Implementation Method 1
The fuel return line comprises a control element system to discharge fuel pressure to the fuel tank when a pressure value in the fuel return line is above a predetermined threshold and to prevent fuel flow into the fuel tank when the pressure value in the fuel return line is not above the predetermined threshold
Implementation Method 2
allowing the return line to act as a dual-function fuel pressure accumulator
Data Source
AI summary
The present application relates to a fuel injection system of an internal combustion engine having an automatic stop-start system, the fuel injection system comprising a high pressure fuel pump, which via a fuel pump line delivers fuel towards a common fuel rail, to which a fuel return line is connected. It is proposed that the fuel return line comprise a control element system, which firstly discharges a fuel pressure to a fuel tank, when a first predefined pressure limit is reached in the fuel return line, and which secondly prevents a further flow of fuel from the return line into the fuel tank, but allows a flow of fuel from the fuel tank into the fuel return line, so that the return line is designed as a fuel pressure accumulator.