Motor-Driven Rotatable Needle Fluid Injector for Urea
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Solution Overview
Problem
Existing urea injection systems for diesel engines lack precise control over urea injection, leading to insufficient or excessive urea discharge, and are prone to clogging due to crystallization, which affects NOx reduction efficiency in exhaust emissions.
Innovation Solution
A fluid injector assembly with a rotatable injector needle and motor-driven coupling members allows for precise control over urea injection, featuring a threaded region and coupling members to move the needle between open and closed positions, and includes a heating element to ensure efficient decomposition of urea into ammonia, preventing clogging and optimizing NOx reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If solenoid or spring activated injection nozzles are used, then the injection system is simple in structure, but precise control over the amount of urea injected is not achieved
Solution Approach 1:
The patent replaces traditional solenoid or spring activated mechanical injection mechanisms with a motor-driven rotatable needle system. The motor provides precise rotational control that translates to precise linear movement of the needle via threaded engagement, enabling accurate control of urea injection quantity while maintaining structural simplicity.
Solution Approach 2:
The injection needle is designed to be rotatable rather than purely linearly actuated. By converting rotational motor motion into linear needle movement through threaded regions, the system achieves dynamic control where the needle position can be precisely adjusted by controlling the rotation angle and speed of the motor, enabling variable injection amounts.
2Productivity
If insufficient amount of urea solution is injected, then the injection system operates efficiently, but NOx is not fully neutralized
Solution Approach 1:
The patent incorporates feedback control mechanisms that monitor the actual urea injection amount and compare it with the required amount for effective NOx neutralization. The motor control system adjusts the needle position based on feedback signals to ensure the precise quantity of urea is injected, maintaining both injection efficiency and NOx neutralization effectiveness.
Solution Approach 2:
The system dynamically changes the injection parameters (needle position, opening duration, injection pressure) based on operating conditions such as engine load, exhaust temperature, and measured NOx levels. This allows the injection system to optimize the urea dosage for each operating condition, ensuring complete NOx neutralization while maintaining high injection efficiency.
3Ease of operation
If compressed air is used for injection and atomization, then the injection process is assisted, but clogging due to crystallization occurs
Solution Approach 1:
The patent changes the physical parameters of the urea solution by incorporating heating elements that maintain the solution temperature above the crystallization point. By controlling the temperature parameter, the system prevents urea crystallization that would cause clogging, while still using compressed air to assist injection and atomization, thus maintaining ease of operation while improving reliability.
Solution Approach 2:
The heating system provides beforehand cushioning by pre-heating the urea solution before it reaches the injection point, preventing crystallization from occurring in the first place. This proactive approach protects the injection system from clogging before it can happen, ensuring continuous reliable operation.
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 system provides improved control over urea injection, ensuring efficient NOx reduction by precisely regulating the amount of urea discharged and preventing clogging, thereby enhancing the performance of selective catalytic reduction systems in diesel engines.
Implementation Method 1
The injector needle includes a threaded region that cooperates with a threaded region of the fluid injector assembly
Implementation Method 2
includes a heating element to ensure efficient decomposition of urea into ammonia, preventing clogging and optimizing NOx reduction
Implementation Method 3
The motor is configured to rotate the injector needle within the injector body which causes the threaded region of the injector to be driven in the first threaded region of the fluid injector assembly to thereby move the injector needle along a longitudinal axis
Data Source
AI summary
The invention provides a fluid injector assembly for the injection of a fluid including an injector body having distal and proximal ends, a fluid inlet disposed towards the proximal end, a fluid outlet disposed towards the distal end, and a fluid pathway extending therebetween the inlet and the outlet. An injector needle is rotatably disposed at least partially in the injector body and is moveable between an open and closed position. The proximal end of the injector needle has a tip that is configured to sealably close the fluid outlet. The fluid injector assembly includes a first threaded region that cooperates with a corresponding threaded region on the needle, and first and second cooperating coupling members that are arranged axially of the injector needle. The first coupling member is attached to a motor, and the second coupling member is attached to a distal end of the injector needle. The motor is configured to rotate the injector needle within the injector body which causes the threaded region of the needle to be driven in the first threaded region of the fluid injector assembly to thereby move the injector needle along a longitudinal axis of the fluid injector assembly between the open and closed positions.