Switchable Rocker Arm for Cylinder Deactivation

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Solution Overview

Problem

Existing systems for deactivating gas exchange in internal combustion engine cylinders often result in high loads on bearings and components, requiring multiple or large components to be moved for activation and deactivation, which is inefficient and prone to wear.

Innovation Solution

A switchable actuating device for a lifting valve featuring a two-part rocker arm with a pivotable first part and a second part mounted on a bearing sleeve, utilizing a locking element for detachable, non-rotatable connection, allowing the rocker arm parts to be coupled or decoupled to control gas exchange, thereby reducing stress and wear on components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If rocker arm or follower arm combinations are used to deactivate gas exchange in individual cylinders, then fuel consumption can be reduced by deactivating injection and gas exchange, but high loads are placed on the bearings or individual components and many or large components must be moved for deactivation or activation

Engineering Contradiction:

Improvefuel consumptionVSAvoidloads on bearings and components

Core Design Contradiction:

Loss of energyVSForce

Solution Approach 1:

The rocker arm is divided into two separate parts: a first rocker arm part that remains stationary and a second rocker arm part that can be independently positioned. By segmenting the rocker arm, the system can deactivate gas exchange by positioning only the smaller second part away from the valve, rather than moving a complete rocker arm assembly, thereby reducing the loads on bearings and components while maintaining the ability to control fuel injection and gas exchange.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If rocker arm or follower arm combinations are used to deactivate gas exchange in individual cylinders, then fuel consumption can be reduced by deactivating injection and gas exchange, but many or large components must be moved for deactivation or activation

Engineering Contradiction:

Improvefuel consumptionVSAvoidnumber and size of components to be moved

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention extracts the essential actuating function from the complete rocker arm assembly and isolates it into a separate, smaller second rocker arm part. This extracted component can be independently positioned to control the valve, allowing deactivation with minimal movement of components. The first rocker arm part remains in place, providing structural support while the second part performs the selective actuation function.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If a locking element is used to rotatably connect the first and second rocker arm parts, then the rocker arm parts can be coupled or decoupled to control gas exchange, but the system must manage the complexity of the locking mechanism

Engineering Contradiction:

Improveability to couple or decouple rocker arm partsVSAvoidlocking mechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical locking mechanisms with a magnetic coupling system. The locking element utilizes magnetic attraction to rotatably connect the first and second rocker arm parts, eliminating the need for traditional mechanical locks, pins, or complex fastening mechanisms. This magnetic-based approach simplifies the overall system while maintaining the ability to couple and decouple the rocker arm parts for selective cylinder deactivation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3899215B1Switchable actuation device for a poppet valve in an internal combustion engine, internal combustion engine and motor vehicle

Publication Date: 2022.12.07 MAN TRUCK & BUS SE

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AI summary

The present invention relates to a switchable actuation device (100) for a gas exchange valve. The switchable actuation device (100) comprises a two-piece rocker arm (10). Said rocker arm comprises a first rocker arm portion (1a), which is mounted pivotably about a rocker arm shaft (2) and to which a bearing sleeve (1a1) is fastened concentrically with the rocker arm shaft (2), and a second rocker arm portion (1b) mounted pivotably on the bearing sleeve (1a1). Furthermore, both the first and the second rocker arm portions (1a, 1b) each comprise a cut-out (3a, 3b), wherein a locking element (4a) of a coupling device (4) of the switchable actuation device (100) can optionally be brought into and out of engagement with the two cut-outs (3a, 3b). An actuation of the poppet valve, preferably a change between a closed position and an open position of the poppet valve, is interrupted if the locking element (4a) is not in engagement with the two cut-outs (3a, 3b). The invention also relates to an internal combustion engine (20) and a motor vehicle (30).