Ejector Break-Point Leak Detection
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Solution Overview
Problem
Existing dual path purge systems in engines fail to detect leaks downstream of the ejector outlet, leading to undetected emissions and operational degradation, as current diagnostic methods focus on sensors upstream of the ejector and do not account for leaks at or beyond the ejector outlet.
Innovation Solution
Incorporating calculated break-points and a hard-mounted outlet in the ejector design to direct leaks to detectable areas upstream, and optionally using a shut-off valve to mitigate leaks by closing the outlet flow when a leak is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are added downstream of the ejector outlet to detect leaks, then leak detection capability is improved, but device complexity and cost increase
Solution Approach 1:
A shut-off valve is introduced as an intermediary component between the ejector outlet and the atmosphere. When a leak is detected upstream, the valve closes to prevent leaked gases from reaching the atmosphere, thereby maintaining reliability without requiring downstream sensors
Solution Approach 2:
The leak detection function is extracted from the downstream region and relocated to the upstream region of the ejector. By detecting leaks at the inlet or orifice location upstream of the outlet, the system eliminates the need for additional downstream sensors while maintaining effective leak detection
2Measurement precision
If extensive monitoring of all ejector sections is implemented, then leak detection precision is improved, but device complexity and sensor requirements increase
Solution Approach 1:
The monitoring system focuses on specific critical locations (inlet or orifice regions upstream of the outlet) rather than uniformly monitoring all ejector sections. This localized approach maintains sufficient leak detection precision by targeting areas where leaks most commonly occur and where detection has the greatest impact
Solution Approach 2:
Instead of implementing complete monitoring of all ejector sections, the system applies partial monitoring to the most critical upstream regions. The shut-off valve provides additional protection by physically blocking leaked gases, compensating for the reduced monitoring scope
3Reliability
If additional sensors are added to the vehicle system to detect ejector leaks, then leak detection capability is improved, but manufacturing cost and system complexity increase
Solution Approach 1:
The shut-off valve serves multiple functions: it acts as a flow control device during normal operation and as a leak mitigation device when leaks are detected. This multi-functionality eliminates the need for additional dedicated leak prevention components, reducing manufacturing cost while maintaining reliability
Solution Approach 2:
The system uses existing upstream leak detection capabilities to trigger the shut-off valve, allowing the system to self-diagnose and self-correct leak conditions without requiring additional specialized sensors or components. The existing sensors serve dual purposes for both upstream leak detection and triggering the protective valve action
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 approach allows for the detection of leaks without additional sensors, reduces the need for extensive monitoring, and minimizes emissions by directing leaks to detectable inlets and shutting off flow when leaks occur, thereby improving engine operation.
Implementation Method 1
an ejector including an orifice, first and second inlets, and an outlet
Data Source
AI summary
Systems and methods for a multi-path purging ejector are disclosed. In one example approach, a dual path purge system for an engine comprises an ejector including a restriction, first and second inlets, and an outlet, at least one break-point at the restriction or inlets, and a shut-off valve coupled to the outlet.