Mechanical Fuel Pump Deactivation via Dynamic Switching
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Solution Overview
Problem
Direct injection fuel systems in internal combustion engines require mechanical fuel pumps, which lead to noise, vibration, and harshness (NVH), parasitic losses, and fuel warming due to their mechanical operation synchronized with the camshaft.
Innovation Solution
A mechanical fuel pump with a deactivating element that can switch between active and inactive configurations, allowing the pump to be operated or deactivated based on engine load, reducing unnecessary operation and associated issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a mechanical fuel pump is used in a direct injection fuel system, then high fuel pressure is achieved, but noise, vibration and harshness (NVH) increase
Solution Approach 1:
The patent applies the dynamics principle by making the fuel pump operable in both active and inactive configurations. The pump can be dynamically switched between operating and deactivated states based on engine conditions, allowing the system to adapt to varying requirements. This resolves the contradiction by enabling high pressure delivery when needed while allowing pump deactivation to reduce NVH when full pressure is not required.
Solution Approach 2:
The patent implements parameter changes by modifying the operational state of the fuel pump between active and inactive configurations. By changing the operational parameter of the pump system, the design achieves high fuel pressure during active operation while reducing NVH through deactivation when appropriate, thus resolving the technical contradiction between pressure delivery and harmful factors.
2Reliability
If a mechanical fuel pump is driven by a camshaft, then the pump operates whenever the camshaft operates, but parasitic losses increase
Solution Approach 1:
The patent applies dynamics by enabling the fuel pump to switch between active and inactive configurations based on actual fuel delivery needs. Instead of continuous operation driven by the camshaft, the pump can be deactivated when not needed, reducing parasitic losses while maintaining reliability when fuel delivery is required.
Solution Approach 2:
The patent extracts the harmful parasitic losses by selectively decoupling the pump operation from continuous camshaft-driven operation. By taking out the unnecessary operational periods and deactivating the pump, the system reduces energy losses while maintaining the mechanical drive connection for when it is needed.
3Reliability
If a mechanical fuel pump operates continuously, then fuel is always delivered to the engine, but fuel warming increases
Solution Approach 1:
The patent applies dynamics by allowing the fuel pump to transition between active and inactive states based on engine requirements. This dynamic operation reduces continuous fuel pumping, thereby reducing the warming effect on fuel while maintaining delivery reliability when the pump is activated.
4Object-affected harmful factors
If a deactivating element is added to the fuel pump, then NVH and parasitic losses are reduced, but device complexity increases
Solution Approach 1:
The patent introduces a deactivating element as an intermediary component between the camshaft-driven mechanism and the pump piston. This mediator allows the system to achieve pump deactivation without fundamentally redesigning the entire fuel pump structure, thereby reducing NVH and parasitic losses while limiting the increase in device complexity.
Data Source
AI summary
A mechanical fuel pump is disclosed for delivering fuel to an engine of a vehicle, the mechanical fuel pump having an activated configuration and a deactivated configuration. A dual fuel system and method are also disclosed for use with the mechanical fuel pump.