Intake System Leak Diagnosis via Mass Flow Balance
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Solution Overview
Problem
Current leakage diagnosis methods in internal combustion engine intake systems are unable to precisely locate and differentiate between leakage sources, leading to unreliable error identification and compensation during regular vehicle operation.
Innovation Solution
A method involving mass flow determination and balance in the intake system, combined with pressure considerations, to accurately identify and characterize leakage mass flows, allowing for targeted compensation measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If general leakage diagnosis methods using lambda values are used, then the presence of leakage can be detected, but the precise position and characteristics of the leakage cannot be determined
Solution Approach 1:
The air conduit is divided into multiple segments (fresh air conduit, air manifold, intake system) and mass flow balances are established for each segment separately. This segmentation allows the leakage position to be identified by comparing the balance results across different segments, transforming a single undifferentiated detection into multiple targeted measurements that reveal the leakage location.
Solution Approach 2:
Mass flow balances serve as intermediary calculations between the raw sensor data and the final leakage diagnosis. By introducing these intermediate balance equations for different conduit segments, the system transforms incomplete lambda value information into comprehensive leakage characterization including position, size, and flow direction.
2Measurement precision
If mass flow balances are established for different conduit segments, then precise leakage position and characteristics can be determined, but the diagnostic system complexity increases
Solution Approach 1:
The existing mass flow sensors and lambda probes in the engine management system are utilized for dual purposes: both for standard engine control functions and for leakage diagnosis. The control unit performs both engine management and leakage detection tasks, eliminating the need for additional dedicated hardware and reducing system complexity despite the enhanced diagnostic capability.
Solution Approach 2:
The diagnostic system utilizes the existing sensor network and control unit already present in the vehicle for leakage detection. The control unit automatically performs mass flow balance calculations and leakage characterization using data from existing sensors, making the system self-sufficient without requiring external diagnostic equipment or additional sensors.
3Reliability
If continuous leakage monitoring is performed during regular operation, then timely compensation measures can be taken, but the computational load and processing time increase
Solution Approach 1:
The control unit continuously calculates mass flow balances and compares them against threshold values during regular engine operation. By performing these calculations in advance and in real-time, the system can immediately detect when a leakage exceeds the threshold and trigger compensation measures without delay, maintaining engine reliability while enabling timely responses.
Solution Approach 2:
The system establishes a continuous feedback loop where mass flow measurements are constantly monitored, leakage is detected through balance calculations, and compensation measures are automatically implemented. This closed-loop feedback mechanism ensures the engine operates reliably despite leakages by continuously adjusting parameters to compensate for the detected leakage.
Data Source
AI summary
A vehicle drive has an internal combustion engine, an air conduit system, an exhaust system and a diagnostic unit for identifying a leak in the air conduit system of the internal combustion engine. The diagnostic unit is designed to carry out a method for diagnosing a leak in an internal combustion engine, including by determining mass flows in the air conduit system, and identifying a leakage mass flow.