Valve Control with Curved Surfaces for Friction Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing valve control systems for internal combustion engines face challenges in achieving reliable and efficient valve lift adjustment at high speeds due to complex designs, high frictional forces, and limited adjustment paths, which restrict fuel consumption savings and increase production and assembly complexities.

Innovation Solution

A valve control system with a rocker arm that rests on curved control surfaces with coordinated radii of curvature, allowing for low-friction adjustment by contacting the cam follower lever with the camshaft's base circle section, and featuring a through-opening for the adjustment device, enabling compact and cost-effective design with minimal energy requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a complex adjustment mechanism with eccentric and actuator is used to adjust valve lift, then valve lift can be adjusted, but the device complexity increases and frictional forces become considerable

Engineering Contradiction:

Improvevalve lift adjustment capabilityVSAvoidadjustment mechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention extracts the adjustment function from a complex eccentric-actuator mechanism and implements it through a simple linear displacement of the cam follower lever's pivot axis relative to the rocker arm. This reduces the adjustment mechanism to essential components only, eliminating unnecessary complexity while preserving valve lift adjustment capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a complex mechanism to create rotational motion for adjustment, the invention inverts the approach by using direct linear displacement of the pivot axis. The adjustment is achieved by moving the pivot axis position rather than rotating an eccentric, fundamentally simplifying the mechanism.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If a complex adjustment mechanism with movable pivot axes is used, then valve lift can be adjusted, but frictional forces increase and the system becomes noisy

Engineering Contradiction:

Improvevalve lift adjustabilityVSAvoidfrictional energy loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The invention removes complex movable pivot mechanisms and retains only the essential linear displacement of the cam follower lever's pivot axis. This extraction of the adjustment function to its simplest form minimizes frictional contact surfaces and eliminates unnecessary moving parts that would generate noise and energy loss.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If an eccentric adjustment mechanism is used, then valve lift can be adjusted, but the adjustment range is limited to approximately 50% of maximum stroke

Engineering Contradiction:

Improvevalve lift adjustment rangeVSAvoidadjustment mechanism design

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention employs a dynamic pivot axis displacement mechanism that allows the cam follower lever's pivot axis to move linearly relative to the rocker arm. This dynamic repositioning enables the full range of valve lift adjustment from minimum to maximum stroke, overcoming the 50% limitation of eccentric mechanisms while maintaining design simplicity.

Inventive Principle:

Principle #15Dynamics

4Loss of energy

If curved control surfaces with coordinated radii of curvature are used, then friction is minimized, but the design complexity increases

Engineering Contradiction:

Improvefrictional energy lossVSAvoidcontrol surface geometry

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The invention applies curved control surfaces with specifically coordinated radii of curvature at the contact points between the cam follower lever and rocker arm. This curvature coordination ensures rolling contact rather than sliding contact, minimizing friction and energy loss while the radii are chosen to achieve this with relatively simple geometric forms.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentEP2837779B1Valve control for a gas exchange valve of a combustion engine

Publication Date: 2019.10.16 TRZMIEL ALFRED

Figure 1
Figure 2

AI summary

The valve control is used to adjust the valve lift of a gas exchange valve and has a cam follower lever (9). A rocker arm (8) is attached to the cam follower lever (9), which actuates the valve (1) and is adjustable for valve lift adjustment by means of an adjusting device (23). The cam follower lever (9) and the rocker arm (8) have curved control surfaces (34; 20; 30). The rocker arm (8) bears with a first control surface (20) against a curved control surface (19) of a machine-side guide element (17) and with a second control surface (30) against a valve element (5). The radii of curvature (R1 to R4) of the control surfaces (34; 19; 30, 20) of the cam follower lever (9), the guide element (17) and the rocker arm (8) are matched to each other so that when the valve lift is adjusted the valve (1) does not open while the cam follower lever (9) rests against the base circle section (39) of the cam (11) of the camshaft (10).The rocker arm (8) is mounted in a floating manner.