Wheel Loader Urea Pipe Thermal Shielding
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Solution Overview
Problem
The reducing agent pipe in wheel loaders is heated by radiant heat from the selective catalyst reduction device, causing the urea aqueous solution to change to ammonia, which reduces the durability of the pipe and associated components.
Innovation Solution
A partition plate is positioned between the selective catalyst reduction device and the vehicle body cover to block radiant heat, with the reducing agent pipe extending between the partition plate and the vehicle body cover to prevent heating, and a supporting member maintains the pipe away from the partition plate to prevent heat transfer. Additionally, the pipe is introduced through a bulging port to avoid severe bending and is configured into two sections for independent heating and replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reducing agent pipe is disposed inside the engine room to connect the reducing agent pump and injection device, then the pipe routing is simplified, but the pipe is heated by radiant heat from the selective catalyst reduction device causing the urea aqueous solution to change to ammonia and reducing component durability
Solution Approach 1:
The reducing agent pipe is divided into two separate pipes: a first pipe connecting the reducing agent pump to the relay member, and a second pipe connecting the relay member to the injection device. This segmentation allows the first pipe to be routed outside the engine room (avoiding radiant heat) while the second pipe remains inside (simplifying connection to injection device).
Solution Approach 2:
A relay member is introduced as an intermediary component between the reducing agent pump and injection device. The relay member serves as a connection point where the first pipe (from pump) and second pipe (to injection device) meet, enabling the pipe system to bypass the radiant heat zone while maintaining functional connectivity.
2Reliability
If the partition plate is added to block radiant heat from the selective catalyst reduction device, then the reducing agent pipe is protected from heating, but the device complexity increases
Solution Approach 1:
A partition plate is introduced as a thermal barrier between the selective catalyst reduction device and the reducing agent pipe. The partition plate blocks radiant heat from reaching the pipe while allowing space for the pipe to extend between the partition plate and vehicle body cover.
3Reliability
If the reducing agent pipe is extended between the partition plate and vehicle body cover to avoid radiant heat, then the pipe is protected from heating, but the pipe installation complexity increases
Solution Approach 1:
The vehicle body cover is designed with a bulging part that creates additional space and flexibility for pipe routing. The bulging part allows the reducing agent pipe to be installed with appropriate curvature and positioning without severe bending, while maintaining the protective configuration between the partition plate and vehicle body cover.
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 configuration effectively prevents the reducing agent pipe from being heated, maintaining the integrity of the urea aqueous solution and reducing the need for premature replacement of components, while allowing for efficient pipe handling and energy-saving heating options.
Implementation Method 1
the reducing agent flowing through the reducing agent pipe is heated by radiant heat from the selective catalyst reduction device housed inside the engine room
Implementation Method 2
the transfer of heat from the partition plate to the reducing agent pipe can be prevented by preventing the reducing agent pipe from coming into contact with the partition plate
Implementation Method 3
The reducing agent pipe preferably has a heating wire for heating the reducing agent flowing therein
Data Source
Figure 1
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AI summary
A wheel loader (1) comprises an engine (18), a selective catalyst reduction device (23), an injection device (24), an engine room (9), a vehicle body cover (40), a first partition plate (31), a urea aqueous solution tank (13), a urea aqueous solution pump (14), and urea aqueous solution pipe (25). The injection device (24) injects a urea aqueous solution into the exhaust gas fed from the engine (18) toward the selective catalyst reduction device (23). The engine room (9) accommodates the engine (18), the selective catalyst reduction device (23), and the injection device (24). The vehicle body cover (40) defines the engine room (9). The first partition plate (31) has a base plate (31 a) disposed between the selective catalyst reduction device (23) and the vehicle body cover (40). The urea aqueous solution tank (13) is disposed outside of the engine room (9). The urea aqueous solution pipe (25) connects the urea aqueous solution pump (14) and the injection device (24), and extends between the vehicle body cover (40) and the first partition plate (31) inside the engine room (9).