Valve Train Switching Device with Offset Actuation

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Solution Overview

Problem

Internal combustion engine valve train switching devices face challenges in achieving high operational reliability while minimizing structural volume, weight, and costs.

Innovation Solution

The design incorporates an execution unit with two switching units and two switching means that can actuate the switching units partially offset in time, reducing the number of required switching means and allowing for independent operation, featuring axially displaceable camshaft sections with different contours and a mechanical execution unit that includes a cam gear for efficient valve train switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple switching means are used to actuate switching units simultaneously, then operational reliability is improved, but device complexity and number of components increase

Engineering Contradiction:
Improveoperational reliabilityVSAvoidnumber of switching means
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The execution unit actuates the two switching units in a periodic sequence rather than simultaneously. The control unit generates actuation signals at different times for each switching unit, creating a time-based periodic action pattern that reduces component requirements while maintaining reliable operation through sequential control

Inventive Principle:
Principle #19Periodic action

2Device complexity

If the number of switching means is reduced, then device complexity and costs are reduced, but operational reliability may be compromised

Engineering Contradiction:
Improvenumber of switching meansVSAvoidoperational reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The single execution unit is designed to perform multiple functions by sequentially actuating different switching units. This multi-functional execution unit can control both switching units with a single mechanism, reducing the total number of switching means required while maintaining the ability to reliably control the valve train through programmed sequential operation

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If switching units are actuated simultaneously, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improveswitching operation efficiencyVSAvoidnumber of switching means
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system transitions from static simultaneous actuation to dynamic sequential actuation. The control unit dynamically adjusts the timing of actuation signals based on operational requirements, allowing the execution unit to adaptively control switching units in sequence. This dynamic approach maintains productivity through flexible timing while reducing device complexity

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2176524B1Internal combustion engine valve train switching device
Publication Date: 2019.12.04 MERCEDES BENZ GROUP AG
  • EP2176524B1 patent drawingFigure 1~2
  • EP2176524B1 patent drawingFigure 3
  • EP2176524B1 patent drawingFigure 4a~4b

AI summary

The invention relates to an internal combustion engine valve train switching device having a switching unit (36). The invention provides that the switching unit (36) has at least one actuating unit (38) having at least two switching units (1, 2) and at least one switching means (3, 4), which is provided to actuate the at least two switching units (1, 2) in at least one operating mode in an at least partial chronological offset.