Engine Water Injection Self-Testing via Knock Sensor Feedback
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Solution Overview
Problem
Existing water injection systems in internal combustion engines face challenges in reliably detecting clogging and contamination, leading to inconsistent performance and potential engine damage due to varying water quality, which is not effectively addressed by current testing methods.
Innovation Solution
A method that predicts expected injection errors based on water quality and adjusts water injection parameters using a combination of feed-forward and feedback controls, allowing for self-testing and accurate control of water injection even with partial clogging, by estimating actual errors through changes in engine operating parameters and correlating water quality with injection errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional flow error testing is used to detect water injection system clogging, then the system can identify some flow issues, but the testing is unreliable due to varying water quality and engine conditions affecting flow error measurements
Solution Approach 1:
The patent introduces an intermediary testing approach by using engine parameters (knock sensor output, spark timing, MAF) as mediators to indirectly assess water injection system health. Instead of directly measuring flow error which is affected by water quality variations, the system uses these engine parameters as intermediate indicators that reflect the actual impact of water injection effectiveness on engine operation, providing a more reliable assessment method.
Solution Approach 2:
The system implements feedback by continuously monitoring engine parameters (knock sensor, spark timing, MAF) and using this information to adjust water injection compensation. The feedback loop compares expected engine behavior with actual behavior, and when deviations are detected, the system compensates by adjusting water injection amounts, thereby maintaining reliable operation despite water quality variations or partial clogging.
2Productivity
If water injection is increased to compensate for undetected clogging, then engine performance may be maintained, but contaminated water causes mineral deposition on injectors and engine parts
Solution Approach 1:
The patent applies partial action by implementing selective water injection compensation only when and where needed. The system monitors specific engine parameters and applies compensation only during conditions where water injection is beneficial (knock mitigation, catalyst cooling) rather than continuously. This partial approach maintains engine performance while limiting the total amount of contaminated water injected, thereby reducing mineral deposition on components.
Solution Approach 2:
The system changes operational parameters by adjusting water injection amounts based on real-time engine conditions and detected clogging levels. When clogging is detected, the system modifies injection parameters (pulse width, injection timing) to compensate for reduced flow, but within controlled limits that prevent excessive injection of contaminated water, thus balancing performance maintenance with contamination mitigation.
3Object-affected harmful factors
If water quality is strictly controlled to prevent contamination, then mineral deposition is reduced, but water purification costs increase
Solution Approach 1:
The patent implements self-service by using the engine itself as the testing and assessment mechanism. Rather than requiring external water quality testing equipment or complex purification systems, the system uses the engine's own operational parameters (knock sensor, spark timing, MAF) to self-diagnose water injection system health and self-adjust compensation. This eliminates the need for separate water quality monitoring infrastructure, reducing purification and testing costs while still preventing harmful effects.
Solution Approach 2:
The system converts the potentially harmful effect of using varied water sources into a benefit by developing a robust compensation strategy. Instead of requiring strict water quality control, the patent embraces the reality of varying water quality and uses engine parameter monitoring to detect and compensate for its effects. This approach transforms the challenge of water quality variation into an opportunity for adaptive control, eliminating purification costs while maintaining engine protection.
4Measurement precision
If multiple sensors are added to reliably detect small changes in water injection flow, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies universality by using existing multi-functional engine components and sensors for water injection system assessment. Rather than adding dedicated flow sensors, the system utilizes existing sensors (knock sensor, spark timing control, MAF sensor) that serve multiple purposes: engine control, knock detection, and water injection effectiveness assessment. This multi-functional approach improves measurement precision without increasing device complexity.
Solution Approach 2:
The system uses engine parameters as intermediaries to indirectly measure water injection effectiveness. Instead of directly sensing water flow which would require complex dedicated sensors, the patent uses readily available engine parameters (knock sensor output, spark timing response, MAF readings) as intermediary indicators that reflect water injection performance. This intermediary approach achieves precise detection of injection issues using existing sensor infrastructure.
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 enables reliable self-testing of the water injection system, reduces engine damage from contaminated water, minimizes purification costs, and extends the benefits of water injection by ensuring consistent engine performance and fuel economy.
Implementation Method 1
when water is injected into the engine intake or cylinders, heat is transferred from the intake air and/or engine components to the water, leading to charge cooling
Data Source
AI summary
Methods are provided for reliably self-testing a water injection system that injects water into the engine responsive to engine operating conditions such as knock, the water injection system refilled manually or via the collection of water on-board the vehicle. Responsive to a water injection error, learned based on a change in a defined set of engine parameters while ramping water injection during selected conditions, the presence of clogging in a water line may be determined. Based on a degree of clogging, subsequent water injection may be appropriately adjusted.