Offset Axis Drum Valve Throttle Body for Linear Air Flow Control
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Solution Overview
Problem
Existing throttle bodies for Otto cycle engines, such as butterfly and slide types, suffer from non-linear air flow relationships, restrictions, and poor performance in dusty environments, leading to inefficiencies and compatibility issues with fuel injection systems.
Innovation Solution
An improved throttle body design featuring an offset axis drum valve with a shaped throat, providing a gradual initial opening, optimal air flow at full throttle, and increased volume in the intake tract, along with a fuel injector pocket for better mixing, addresses these issues by reducing tolerances and manufacturing costs while mimicking the air flow of butterfly throttles for compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a butterfly type throttle body is used, then the structure is simple, but it creates restriction even when fully open and provides a non-linear relationship between throttle position and air flow
Solution Approach 1:
The patent inverts the traditional butterfly valve design by using a drum valve that rotates perpendicular to the air flow direction. Instead of a plate blocking the air path, a cylindrical drum rotates to gradually open the air passage, eliminating the central shaft restriction and providing a more linear throttle response.
Solution Approach 2:
The invention transitions from a two-dimensional plate rotation (butterfly valve) to a three-dimensional drum rotation. The drum valve rotates around an axis perpendicular to the air flow, creating a gradual opening that eliminates the abrupt non-linear behavior of plate-type throttles while maintaining structural simplicity.
2Productivity
If a slide type throttle body is used, then it can provide better air flow, but it requires an extension of the housing and may become jammed in dusty environments
Solution Approach 1:
Instead of a slide moving linearly perpendicular to the air flow, the patent uses a drum valve that rotates around an axis perpendicular to the air flow direction. This rotational motion eliminates the sliding contact that causes jamming in dusty environments while maintaining effective air flow control.
Solution Approach 2:
The drum valve design extracts the throttling function from the housing extension required by slide-type throttles. The drum rotates within the existing housing space, eliminating the need for extended housing and the associated jamming risks while preserving air flow performance.
3Productivity
If another throttle body type is substituted for a butterfly type, then it may improve performance, but it creates compatibility issues with existing fuel injection control units
Solution Approach 1:
The drum valve is designed to replicate the non-linear air flow characteristics of butterfly throttles, making it universally compatible with existing fuel injection control units. The valve's rotation profile can be adjusted to match various throttle response curves, allowing substitution without requiring control unit reprogramming.
Solution Approach 2:
The patent adjusts the geometric parameters of the drum valve (radius, width, rotation profile) to achieve desired air flow characteristics. By varying these parameters, the same drum valve design can accommodate different throttle response requirements while maintaining compatibility with existing control systems.
Data Source
AI summary
An improved throttle body includes an offset axis drum valve and shaped throat. The offset axis and shaped throat provide gradual initial opening for better throttle control and the drum valve includes a lower face matching the profile of the air path through the throttle body when rotated to a fully open throttle position, providing an optimal flow at full throttle. The offset axis drum further includes a slightly decreasing radius. As the drum opens, the surface of the drum retreats from the throttle body wall providing clearance for dusty environments and reducing tolerances for reduced manufacturing cost. A fuel injector pocket position provides a spray pattern aligned with an initial air flow as the throttle body opens providing better mixing at part throttle. The throttle body further creates a cavity under the drum in the closed position providing an increased volume in the intake tract which improves throttle response.