High-Pressure Pump Cooling via Liquid Fuel Circulation
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Solution Overview
Problem
Dual-fuel internal combustion engines face challenges in cooling the high-pressure pump without increasing the pump's size, as existing solutions require additional volume and energy consumption, especially when operating with gaseous fuels that do not provide a fuel flow through the gasoline direct injection system.
Innovation Solution
A high-pressure pump design with a low-pressure liquid fuel inlet, high-pressure outlet, and a continuous liquid fuel circulation system, utilizing upstream and downstream pressure drop members to maintain temperature and supply pressure, ensuring liquid fuel circulation through the pump even in the absence of engine fuel consumption, thus avoiding stagnation and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an external coolant chamber is integrated around the high-pressure pump to cool the pump, then the pump temperature is maintained below cavitation threshold, but the engine volume increases in a constrained environment
Solution Approach 1:
The invention merges the cooling function with the existing fuel circulation system by routing liquid fuel through the low-pressure chamber and inlet valve area. This integrates the cooling pathway within the pump's existing structure rather than adding an external coolant chamber, thus maintaining pump temperature below cavitation threshold without increasing engine volume.
Solution Approach 2:
The liquid fuel serves dual purposes: it is both the working fluid for injection and the cooling medium for the high-pressure pump. By making the fuel circulation system multi-functional (serving both injection and cooling), the patent eliminates the need for a separate cooling system that would increase engine volume.
2Reliability
If the high-pressure pump is cooled by liquid fuel circulation during gas-powered operation, then cavitation is prevented, but additional energy consumption occurs to maintain fuel circulation
Solution Approach 1:
The system uses the fuel circulation that is already necessary for engine operation to provide the cooling function. The low-pressure pump continues its normal operation to supply fuel to the high-pressure pump, and this existing fuel flow automatically cools the pump during gas-powered operation, eliminating the need for additional energy-consuming cooling systems.
Solution Approach 2:
The fuel circulation is maintained continuously through the low-pressure chamber and inlet valve area during gas-powered operation, ensuring uninterrupted cooling. This continuous circulation prevents cavitation without requiring intermittent or additional energy input, as the fuel flow is already part of the normal engine operation cycle.
3Temperature
If the high-pressure pump size is increased to improve cooling capacity, then the pump temperature is maintained, but the empty area for pedestrian safety is reduced
Solution Approach 1:
Instead of increasing the pump's external dimensions (particularly height) to improve cooling, the invention utilizes the internal three-dimensional space within the existing pump structure. By routing fuel through the low-pressure chamber and inlet valve area, the cooling function is achieved within the pump's existing volume envelope, maintaining the clearance required for pedestrian safety.
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 design effectively maintains the high-pressure pump temperature below 50°C without increasing the pump's size or energy consumption, ensuring efficient operation during dual-fuel engine phases.
Implementation Method 1
The fuel inside the high-pressure pump is susceptible to cavitation due to hydrodynamic conditions, such as the pressure drop during the suction phase. This cavitation leads to pump damage. Therefore, it is necessary to maintain the temperature inside the pump below a certain threshold to prevent cavitation.
Implementation Method 2
The fuel inside the high-pressure pump is susceptible to cavitation due to hydrodynamic conditions, such as the pressure drop during the suction phase. This cavitation leads to pump damage.
Implementation Method 3
a plunger that moves in translation within the pump body. The low-pressure chamber is located axially below the plunger, in particular its piston
Data Source
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AI summary
High-pressure pump (100) of a liquid fuel direct injection carburetion system of a dual-fuel internal combustion engine of a motor vehicle configured to burn liquid fuel and gaseous fuel, said high-pressure pump (100) comprising a low-pressure liquid fuel inlet (102), a high-pressure liquid fuel outlet (104), a compression chamber (105), a low-pressure chamber (106) and a plunger (108) movable in translation within the pump, the pump (100) further comprising an inlet and outlet valve (111, 112) of the compression chamber (105). The high-pressure pump (100) includes a low-pressure liquid fuel outlet (120) connected to the low-pressure chamber (106) and configured to create a continuous flow of liquid fuel through the inlet valve (111) and the low-pressure chamber (106) during engine operation with gaseous fuel.