Indirect Fuel Temperature Determination via Rail and Injector Sensors
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Solution Overview
Problem
It is difficult and costly to measure the mean temperature of pressurized fuel in high pressure fuel systems, which is necessary for estimating the amount of fuel injected into engines, due to the high pressure conditions and the need for direct temperature measurement at multiple points within the system.
Innovation Solution
A method to determine the mean temperature of pressurized fuel by measuring temperatures in different sections of the high pressure fuel system, such as the common rail and fuel injectors, and using these measurements to calculate a total temperature that accounts for varying fuel volumes, allowing for indirect determination without additional hardware complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct temperature measurement is used in high pressure fuel system, then temperature measurement precision is improved, but device complexity and cost increase due to specialized high-pressure sensors
Solution Approach 1:
The patent uses the fuel rail body and injector bodies as intermediary objects to indirectly measure fuel temperature. Temperature sensors are placed on these solid components rather than directly in the high-pressure fuel, allowing standard sensors to measure the temperature of the container walls which then represent the fuel temperature through thermal equilibrium, thus avoiding the need for complex high-pressure resistant temperature sensors
Solution Approach 2:
The patent replaces direct mechanical/physical temperature measurement in high-pressure fuel with an indirect measurement system using thermal conduction through the fuel rail and injector bodies. Instead of measuring temperature directly in the fuel under high pressure, the system measures temperature through the solid components that are in thermal contact with the fuel
2Measurement precision
If mean temperature of all pressurized fuel is measured, then fuel weight estimation accuracy is improved, but measurement precision deteriorates due to inability to measure temperature at all points simultaneously
Solution Approach 1:
The patent divides the high-pressure fuel system into multiple measurement sections, placing temperature sensors at different locations (fuel rail body and injector bodies). Each sensor measures the temperature of its local section, and these segmented measurements are then combined through volume-weighted averaging to reconstruct the overall mean temperature, thus preserving temperature distribution information while achieving accurate mean temperature measurement
Solution Approach 2:
The patent merges multiple local temperature measurements from different sections of the fuel system into a single mean temperature value. By combining the temperature data from the fuel rail section and injector sections with their respective volume weights, the system creates a comprehensive representation of the overall fuel temperature that accounts for spatial variations
3Reliability
If multiple temperature sensors are deployed in high pressure fuel system, then temperature measurement coverage is improved, but device complexity increases due to additional sensors and wiring
Solution Approach 1:
The patent makes the fuel rail body and injector bodies serve dual functions: they act as both structural components of the fuel system and as temperature sensing elements. By placing standard temperature sensors on these existing components, the system achieves multiple temperature measurement points without adding dedicated sensing structures, thus improving measurement coverage while minimizing additional complexity
Solution Approach 2:
The fuel rail and injector bodies serve themselves as temperature sensing elements. These structural components naturally conduct and maintain thermal equilibrium with the fuel, so they provide temperature information without requiring separate, complex sensing mechanisms. The existing structural components become self-sufficient temperature indicators
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
Enables reliable estimation of the fuel weight injected into engines using existing sensors, reducing production costs and hardware complexity by providing a continuous mean temperature measurement for engine control systems.
Implementation Method 1
determining a first temperature T1 for a first fuel volume V1 included in a first section of the high pressure fuel system... determining a second temperature T2 for a second fuel volume V2 included in a second section of the high pressure fuel system
Data Source
AI summary
A method and a system for determining a temperature for pressurized fuel included in a high pressure fuel system arranged for providing fuel to an engine are presented. The method includes determining a first temperature for a first fuel volume included in a first section of the high pressure fuel system, where the first section includes a common rail fuel system. The method further includes determining a second temperature for a second fuel volume included in a second section of the high pressure fuel system, where the second section includes at least one fuel injector arranged in a cylinder head of the engine. The method also includes the step of determining the temperature for the pressurized fuel based at least on the first temperature and on the second temperature.