Fuel Injector Actuator Cooling via Segmented Passages
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Solution Overview
Problem
High injection pressures in internal combustion engines lead to increased fuel temperatures, which result in the oxidation of fuel and the deposition of debris on fuel injector components, causing thermal issues and reducing the longevity of the injector's performance.
Innovation Solution
A fuel injector design that incorporates a separate cooling fluid passage to maintain the internal temperature below the debris formation temperature, using cooling fuel at a lower pressure and temperature to convectively cool the actuator and surrounding components, thereby reducing deposit formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high injection pressures are used to improve fuel injection performance, then fuel temperature increases causing oxidation and debris deposition on injector components
Solution Approach 1:
The fuel system is segmented into separate cooling and injection pathways. A dedicated cooling passage delivers cooling fuel to the actuator bore, while a separate injection passage delivers injection fuel to the nozzle. This segmentation allows independent control of cooling and injection functions, enabling high injection pressure operation without excessive temperature rise that causes oxidation and debris formation.
Solution Approach 2:
Cooling fuel acts as an intermediary substance that absorbs heat from the actuator and surrounding components before being discharged. This intermediary cooling fuel prevents direct thermal transfer to the injection fuel, thereby preventing oxidation and debris deposition on injector components while maintaining high injection pressure performance.
2Temperature
If cooling fuel is mixed with injection fuel in the same passage, then the temperature of injected fuel increases reducing cooling effectiveness
Solution Approach 1:
The fuel passages are segmented into distinct cooling and injection pathways that do not mix. The cooling passage delivers cooling fuel through the actuator bore to cool internal components, while the injection passage delivers injection fuel to the nozzle. This segmentation maintains cooling effectiveness by preventing warm injection fuel from counteracting the cooling process.
Solution Approach 2:
The cooling and injection fuel flows are separated in the spatial dimension by providing dedicated passages for each function. The cooling passage is positioned to deliver cooling fuel directly to the actuator bore and surrounding components, while the injection passage is positioned to deliver injection fuel to the nozzle. This spatial separation prevents mixing and maintains the independence of each fuel flow's temperature characteristics.
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
The solution effectively reduces the accumulation of debris on internal components, allowing the fuel injector to operate efficiently at higher injection pressures and extending its operational lifespan by maintaining optimal temperatures.
Implementation Method 1
using cooling fuel at a lower pressure and temperature to convectively cool the actuator and surrounding components
Data Source
AI summary
A fuel injector includes an injector body forming an actuator portion. An actuator bore is formed in the actuator portion and is at least partially defined by an inner surface and by an end surface. An actuator disposed in the actuator bore and has an outer surface such that a flow channel can be defined between the inner surface of the actuator bore and the outer surface of the actuator. A cooling flow passage is formed in the injector body, in fluid communication with the actuator bore, and is adapted to supply cooling fluid to the actuator bore. A drain passage is formed in the injector body, in fluid communication with the actuator bore. An internal cooling fluid flow path extends from the cooling flow passage, through the flow channel, and from the flow channel through the drain passage.