DEF Delivery Pressure-Wave Diagnosis for Fluid Density Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing DEF delivery monitoring systems struggle to accurately determine the physical parameters of Diesel Exhaust Fluid (DEF) in the delivery system due to the challenging environmental conditions and the difficulty in installing sensors within the conduit, leading to unreliable estimates of fluid density and temperature.
Innovation Solution
A method that uses pressure wave propagation time to diagnose the fluid density and temperature of DEF in the conduit without requiring additional sensors, utilizing existing components like pressure sensors and injectors to calculate fluid density and temperature based on wave propagation speed and predefined relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are installed directly in the DEF delivery system to monitor temperature and fluid density, then measurement precision is improved, but device complexity and difficulty of installation increase due to high temperature environments and conduit constraints
Solution Approach 1:
The patent uses pressure wave propagation as an intermediary mechanism to indirectly measure DEF physical parameters. Instead of installing direct temperature and density sensors in the harsh environment, the system uses pressure sensors at two locations to detect pressure waves generated by injector operation. The wave propagation time between locations serves as a mediator that reflects DEF properties without requiring direct contact with the fluid in extreme conditions.
Solution Approach 2:
The patent replaces complex mechanical sensor systems with an acoustic pressure wave-based measurement approach. Rather than using direct mechanical or electrical sensors that would be damaged by high temperatures, the system uses the propagation characteristics of pressure waves (acoustic mechanism) to infer fluid properties. This substitution allows measurement without physical sensor exposure to the harsh DEF environment.
2Device complexity
If monitoring systems estimate DEF parameters based on source tank conditions, then device complexity is reduced, but measurement precision deteriorates due to environmental differences between tank and delivery system
Solution Approach 1:
The system uses the injector's own operation to generate the pressure waves for measurement. The injector, which is already a required component for DEF delivery, serves dual purposes: delivering fluid and generating the pressure waves needed for monitoring. By using the injector's inherent operation (self-service) rather than requiring separate monitoring equipment, the system achieves accurate measurement without adding significant complexity.
Solution Approach 2:
The system establishes a feedback loop where pressure waves generated by injector operation are detected at two locations, and the propagation time information is used to continuously monitor and adjust understanding of DEF physical parameters. This feedback mechanism allows the system to adapt to changing conditions in real-time, providing accurate measurements that reflect actual delivery system conditions rather than static tank conditions.
3Measurement precision
If additional fluid density or temperature sensors are installed in the conduit, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent makes the existing pressure sensors serve multiple functions: they both monitor system pressure for operational control and simultaneously enable physical parameter measurement through wave propagation timing. By making the pressure sensors universal (serving both control and measurement functions), the system avoids adding separate dedicated measurement sensors, thereby reducing device complexity while maintaining measurement capability.
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
Provides accurate diagnostic information on DEF quality and composition, enabling effective control of the delivery system, preventing unnecessary maintenance and ensuring optimal operation by detecting changes in DEF properties.
Implementation Method 1
determine a wave propagation time indicative of a time it takes for the pressure wave to propagate from the first location to the second location; determine a physical parameter of the DEF in the delivery system based on the wave propagation time
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of diagnosing a physical parameter of diesel emission fluid (DEF) in a DEF delivery system (12, 112), the DEF delivery system (12, 112) comprising an injector (24) for injecting DEF into a vehicle exhaust after-treatment system (10) and a conduit which connects the injector (24) to a source of DEF (20), the method comprising: operating the injector (24) to inject DEF into the vehicle exhaust after- treatment system (10); receiving a first input signal indicative of a pressure wave being at a first location (L1) in the conduit, the pressure wave resulting from an operation of the injector (24); receiving a second input signal indicative of the pressure wave being at a second location (L2) in the conduit which is downstream from the first location (L1); determining a wave propagation time indicative of the time it takes for the pressure wave to propagate from the first location (L1) to the second location (L2); and diagnosing a physical parameter of the DEF in the delivery system (12, 112) based on the wave propagation time.