Fuel Injection Pressure Control via Overrun Mode Deactivation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In fuel injection systems, faults such as spring breakage in the inlet valve can lead to increased delivery power of the high-pressure fuel pump, causing undesired pressure increases in the high-pressure region, which can result in misfiring or breakdown of the internal combustion engine, especially during overrun mode or low injection quantity states.
Innovation Solution
An operating method is implemented where a pressure-limiting valve discharges excess fuel from the high-pressure region into the pressure chamber of the high-pressure fuel pump when a predefined opening pressure is overshot, deactivating the overrun mode to ensure the engine operates only in injection mode, maintaining pressure below the maximum admissible pressure for the injector valve, and adjusting the injector valve actuation to align with pressure troughs to prevent shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the high-pressure fuel pump delivers increased volume flow in fault situations, then the delivery power is improved, but the pressure in the high-pressure region increases undesirably
Solution Approach 1:
The control device applies preliminary anti-action by deactivating the overrun mode before the pressure can reach dangerous levels. When a fault situation is detected, the control device immediately switches off the overrun mode, preventing the pressure buildup that would otherwise occur during this operating state.
Solution Approach 2:
The fault situation, which initially causes harmful pressure increase, is converted into a beneficial operating condition. By deactivating the overrun mode, the system ensures that the injector valve can still open reliably even at reduced pressure, transforming a potentially damaging situation into one where the injection system continues to function safely.
2Reliability
If the overrun mode is allowed to operate in fault situations, then the engine can continue running, but the pressure increases beyond maximum admissible levels causing misfiring or breakdown
Solution Approach 1:
The control device takes preliminary anti-action by preventing the harmful effect before it occurs. Upon detecting a fault situation, it immediately deactivates the overrun mode, thereby preventing the pressure from exceeding the maximum admissible level that would cause misfiring or engine breakdown.
Solution Approach 2:
The system uses feedback from the fault detection to automatically adjust the operating mode. When a fault is detected, the control device receives feedback and responds by switching off the overrun mode, creating a closed-loop control system that adapts to fault conditions and maintains safe operating parameters.
3Stress or pressure
If the pressure-limiting valve discharges fuel into the pressure chamber during delivery phase, then the pressure is limited, but the valve is hydraulically blocked and cannot discharge
Solution Approach 1:
The system dynamically adjusts the operating mode based on the pump cycle phase. The pressure-limiting valve is designed to discharge fuel into the pressure chamber, and the system exploits the dynamic pressure differences between delivery and suction phases to enable discharge only when hydraulically possible, i.e., during the suction phase when the valve is not blocked.
Data Source
AI summary
Embodiments relate to an operating method for operating a fuel injection system of an internal combustion engine, wherein, upon a detection of a fault in the fuel injection system, and wherein a predefined pressure is overshot in a high-pressure region of the fuel injection system, an overrun mode of the internal combustion engine is deactivated, such that the internal combustion engine is operated exclusively in an injection mode.