High Pressure Fuel Pump Parallel Cooling Flow
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Solution Overview
Problem
High-pressure fuel pumps face challenges in maintaining efficient operation due to increased core temperatures and fuel leakage, which contaminates engine lubricating oil and reduces its viscosity and effectiveness, as higher pressures lead to thermal expansion and a looser fit between the pump plunger and barrel, allowing fuel to escape.
Innovation Solution
A high-pressure fuel pump design incorporating a parallel cooling fuel flow system with an annular cooling ring and drain groove, where a first fuel path directs cooling fuel along the barrel's outer surface, and a second fuel path delivers fuel from the cooling ring to the drain groove, forming a parallel flow that cools the leakage fuel and reduces thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fuel pressure is increased to exceed 2600 bar to meet emissions criteria and improve fuel efficiency, then fuel pressurization capability is improved, but barrel temperature increases causing thermal expansion and fuel leakage
Solution Approach 1:
The fuel flow path is segmented into two separate paths: a first path through the barrel core for cooling, and a second path through the annular space for contamination removal. This segmentation allows independent optimization of cooling efficiency and contamination control without interfering with each other
Solution Approach 2:
Cooling fuel is introduced through the first fuel path before the fuel reaches the barrel core, pre-cooling the barrel in advance. This preliminary cooling action prevents excessive temperature rise during high-pressure operation, maintaining tighter tolerances and reducing fuel leakage
2Reliability
If cooling fuel flow is increased to reduce barrel temperature and maintain tight tolerances, then fuel leakage is reduced, but fuel contamination in the drive system increases
Solution Approach 1:
The fuel flow path is segmented into two separate paths: a first path through the barrel core for cooling, and a second path through the annular space for contamination removal. This segmentation allows independent optimization of cooling efficiency and contamination control without interfering with each other
Solution Approach 2:
The fuel leakage that would normally contaminate the drive system is redirected through the second fuel path. By converting the harmful leakage flow into a useful cooling and cleaning flow through the annular space, the system transforms contamination risk into an beneficial contaminant removal mechanism
3Device complexity
If a single fuel path is used for cooling, then device complexity is reduced, but cooling effectiveness and contamination control are insufficient
Solution Approach 1:
The fuel flow path is segmented into two separate paths: a first path through the barrel core for cooling, and a second path through the annular space for contamination removal. This segmentation allows independent optimization of cooling efficiency and contamination control without interfering with each other
Solution Approach 2:
The dual fuel path system serves multiple functions simultaneously: the first path provides core cooling, the second path removes contaminants, and both paths work together to maintain optimal operating conditions. This multi-functionality achieves superior reliability without requiring separate independent systems
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 high pressures while minimizing fuel leakage and contamination, enhancing fuel pump durability and reliability by maintaining lower barrel temperatures and reducing the pressure gradient that causes fuel vaporization and leakage.
Implementation Method 1
a first fuel path that includes a supply passage fluidically coupled to a fuel supply and the annular cooling ring... directing a cooling fuel flow through the annular cooling ring
Implementation Method 2
a second fuel path that includes a parallel fuel passage fluidically coupled to the drain groove and the first fuel path to deliver fuel from the first fuel path to the annular drain groove
Data Source
Figure 1
Figure 2
AI summary
A high pressure fuel pump with parallel cooling fuel flow is disclosed wherein a fuel pump barrel having a substantially cylindrical plunger bore with an annular drain groove is provided. A first fuel path is provided that fluidically couples a fuel supply to an annular cooling ring formed on the outer surface of the barrel. The first fuel path further fluidically couples the annular cooling ring to a storage tank via an exit passage. A second, parallel fuel path is provided that fluidically couples the first fuel path to the drain groove, and further includes a drain passage fluidically coupled to the drain groove and the first fuel path via the storage tank.