Abnormality Detection for Urea Injection Valves via Pump Speed Monitoring
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Solution Overview
Problem
Existing abnormality determination devices for urea water injection valves in exhaust gas purification systems are unable to accurately detect abnormalities, such as crystallization or foreign matter ingress, leading to inconsistent urea water injection amounts.
Innovation Solution
The implementation of a pump control unit that performs an abnormality determination process by monitoring the rotation speed of the urea water pump and calculating the actual injection amount based on a correlation between the rotation speed and injection amount, allowing for precise detection of abnormalities in the injection valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing abnormality determination devices are used, then the system structure remains simple, but the measurement precision of injection valve abnormalities is insufficient
Solution Approach 1:
The patent replaces complex mechanical abnormality determination devices with an electronic control unit that uses rotational speed sensors and calculation logic to detect injection valve abnormalities. The control unit determines abnormalities by comparing rotational speeds at different injection states and calculating injection amounts, substituting mechanical detection mechanisms with electronic sensing and computational methods.
2Measurement precision
If rotational speed monitoring is implemented for abnormality determination, then the measurement precision improves, but the use of energy increases
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the rotational speed of the pump during injection operations and uses this feedback information to calculate actual injection amounts. By comparing the calculated injection amounts with expected values, the system determines valve abnormalities without requiring additional energy-intensive mechanical testing or multiple sensors.
Data Source
AI summary
An abnormality determination device is used in an exhaust gas purification system. The exhaust gas purification system is disposed in an exhaust gas passage of an internal-combustion engine and includes an injection valve for injecting a liquid reducing agent to a NOx purification catalyst for purifying NOx in an exhaust gas, and a pump for pressurizing and supplying the reducing agent to the injection valve via a reducing agent passage. The abnormality determination device includes an acquisition section acquiring a rotation speed of the pump when the injection valve is injecting the reducing agent as an injection time rotation speed; and a determiner determining whether the injection valve has an abnormality based on the injection time rotation speed.