Intake Tract Coking Detection via Variable Valve Timing
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Solution Overview
Problem
Coking in the intake tract of internal combustion engines with direct fuel injection is difficult to detect objectively and requires disassembly for visual inspection, leading to labor-intensive and subjective assessments, which can result in unnecessary cleaning or replacement of engine components.
Innovation Solution
A method using a vehicle-external or engine control unit-based testing device that increases idle speed and controls intake valve opening timing to detect coking by measuring rough running characteristics, allowing for objective assessment without disassembly, and potentially initiating automatic cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection is used to detect coking, then detection can be performed, but disassembly of engine components is required which is labor-intensive
Solution Approach 1:
The patent replaces the mechanical disassembly approach with an electronic sensing system. A sensor detects coking in the intake tract while the engine is running, substituting physical teardown with electronic measurement. This resolves the contradiction by enabling detection without disassembly, thus saving time while maintaining detection capability.
Solution Approach 2:
The patent introduces an intermediary sensing system between the engine operator and the coking condition. Instead of direct visual inspection requiring disassembly, the sensor acts as an intermediary that provides indirect measurement of coking through parameters like airflow characteristics or pressure drops, enabling detection without mechanical access.
2Measurement precision
If visual inspection is used to detect coking, then detection can be performed, but the assessment is subjective and lacks objectivity
Solution Approach 1:
The patent replaces subjective human visual assessment with objective electronic sensing. The sensor provides quantifiable measurements of coking conditions, eliminating the subjectivity inherent in visual inspection. This resolves the contradiction by providing both detection capability and objective, reliable assessment through electronic data rather than human judgment.
Solution Approach 2:
The patent implements a feedback system where sensor data provides continuous, objective information about coking levels. This feedback mechanism replaces subjective visual assessment with measurable, repeatable data that can be objectively analyzed, ensuring consistent and reliable detection results across different testing instances.
3Measurement precision
If the engine is disassembled for visual inspection, then coking can be detected, but the process becomes complex and labor-intensive
Solution Approach 1:
The patent replaces the complex mechanical disassembly process with a simpler electronic sensing system. The sensor can be integrated into the existing engine structure and provides detection capabilities without requiring breakdown of engine components. This resolves the contradiction by maintaining detection precision while significantly reducing process complexity.
Solution Approach 2:
The patent extracts the detection function from the mechanical disassembly process. Instead of requiring removal of components to inspect for coking, the sensing capability is extracted and implemented as a separate measurement system that operates on the running engine, simplifying the overall detection process.
Data Source
AI summary
A method for detecting coking in the intake tract of an internal combustion engine having direct fuel injection is provided. The internal combustion engine has variable intake valve control. The variable intake valve control makes it possible to change the open time of the intake valves in relation to the crank angle of the crankshaft. In the method, the internal combustion engine is operated in idling mode at an idling rotational speed that is elevated in comparison with the normal idling operation. In order to perform the measurement, the open time of the intake valves is also shifted in an advanced direction. An uneven-running characteristic value of the internal combustion engine that is characteristic of the uneven running of the internal combustion engine is determined, and the presence of coking in the intake tract can be detected on the basis of the uneven-running characteristic value.