Valve Train Cam Carrier Shifting Detection via Induced Voltage Integration

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for operating valve trains in internal combustion engines lack reliable detection of the driver's expulsion from sliding slots, leading to potential inaccuracies in shifting the cam carrier to target positions.

Innovation Solution

A method that integrates the induced voltage within a specific rotational angle range associated with the ejection region and generates a confirmation signal when the integrated voltage exceeds a threshold level, ensuring accurate detection of the driver's expulsion from the sliding slot, even in the presence of multiple sliding slots with non-overlapping ejection regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If voltage detection is performed without integration over rotational angle range, then detection simplicity is maintained, but measurement precision of driver expulsion detection deteriorates

Engineering Contradiction:

Improvedriver expulsion detection accuracyVSAvoidvoltage detection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical position sensing systems with an electrical voltage detection system. By detecting voltage induced in the actuator during driver expulsion and integrating it over a specific rotational angle range, the system achieves precise detection of driver expulsion events without requiring additional mechanical sensors or complex positioning mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements feedback by detecting the voltage induced in the actuator during driver expulsion, integrating this voltage signal over a predetermined rotational angle range, and using the integrated value to confirm successful driver expulsion. This feedback mechanism enables the system to verify cam carrier positioning accuracy and detect any deviations from the target position.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If multiple sliding slots with overlapping ejection regions are used, then shifting flexibility is improved, but reliability of ejection region assignment deteriorates

Engineering Contradiction:

Improveshifting flexibilityVSAvoidejection region assignment accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the rotational angle range into multiple predetermined ranges, each corresponding to a specific sliding slot's ejection region. By integrating the induced voltage signal only within the predetermined rotational angle range associated with each specific sliding slot, the system can reliably determine which slot is being used for the current shifting operation, even when multiple slots are available.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning specific integration ranges to specific sliding slots based on their spatial and temporal characteristics. Each sliding slot has its own dedicated rotational angle range for voltage integration, allowing the system to distinguish between different slots and their corresponding ejection regions through localized signal processing.

Inventive Principle:

Principle #3Local quality

3Reliability

If driver expulsion detection is not monitored, then system simplicity is maintained, but reliability of cam carrier positioning deteriorates

Engineering Contradiction:

Improvecam carrier positioning accuracyVSAvoidmonitoring system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the actuator's own electrical characteristics (induced voltage during driver expulsion) as the detection mechanism. The actuator serves dual purposes: it both performs the shifting function and provides the signal for monitoring driver expulsion and confirming cam carrier positioning. This self-service approach eliminates the need for separate monitoring sensors or systems.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Inventive Principle:

Principle #23Feedback

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 significantly enhances the reliability of confirming the successful expulsion of the driver from the sliding slot, allowing precise assignment of the confirmation signal to the respective ejection region, ensuring accurate shifting of the cam carrier.

Implementation Method 1

a voltage induced in the actuator by the expulsion is detected

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9611765B2Method for operating a valve train of an internal combustion engine and corresponding valve train

Publication Date: 2017.04.04 AUDI AG

AI summary

A method and apparatus for operating a valve train of an internal combustion engine having a main camshaft for which at least one rotationally-fixed cam carrier is provided that can be shifted between two axial positions is disclosed. An actuator cooperates with at least one shift gate to axially shift the cam carrier into a target position. The actuator comprises a driver that is extended in the direction of at least one sliding slot of the shift gate to shift the cam carrier. The sliding slot has an ejection ramp in an ejection region that ejects the driver out of the sliding slot until the conclusion of the shift. A voltage induced in the actuator by the ejection is detected, the induced voltage is integrated across a rotational-angle range associated with the ejection region, and a confirmation signal is generated when the integrated voltage exceeds a threshold level.