Multi-Cylinder Exhaust Throttle Valve Common Axis Design

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Solution Overview

Problem

In multi-cylinder engines equipped with exhaust turbochargers, the branching of exhaust passages leads to a decrease in the flowing-down power of exhaust gas, making it difficult to operate the turbocharger efficiently and affecting engine torque, especially at low engine speeds.

Innovation Solution

An exhaust passage structure with rotary throttle valves supported by a common axis, arranged in independent passages coupled to non-adjacent cylinders, creating a suction effect that increases the speed of exhaust gas and prevents it from flowing into other passages, thereby improving the scavenging effect and dynamic supercharging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the exhaust passage branches into plural independent passages, then each cylinder can have its own exhaust flow path, but the exhaust gas expands into other passages and loses flowing-down power

Engineering Contradiction:

Improveindependent exhaust flow path for each cylinderVSAvoidflowing-down power of exhaust gas

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The exhaust passage is divided into multiple independent passages, each serving a specific cylinder. Throttle valves are installed in each passage to independently control the exhaust flow, preventing gas from one passage from interfering with others while maintaining separate flow paths for each cylinder.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Throttle valves are used to dynamically adjust the opening area in each independent passage, changing the flow parameters of exhaust gas. By controlling the throttle valve opening, the system can prevent exhaust gas from expanding into other passages while maintaining adequate flowing-down power to the turbocharger.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the exhaust turbocharger is arranged downstream of the collective portion, then all cylinders can be connected to the turbocharger, but the exhaust gas loses flowing-down power before reaching the turbocharger

Engineering Contradiction:

Improveconnection of all cylinders to turbochargerVSAvoidflowing-down power of exhaust gas

Core Design Contradiction:

Adaptability or versatilityVSPower

Solution Approach 1:

Throttle valves are installed upstream in each independent passage before the exhaust gas reaches the collective portion and turbocharger. These valves preliminarily control and direct the exhaust flow, ensuring that the gas maintains its flowing-down power throughout the passage and arrives at the turbocharger with sufficient energy.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If multiple throttle valves are installed in independent passages, then exhaust flow can be controlled, but the number of parts and complexity increases

Engineering Contradiction:

Improveexhaust flow controlVSAvoidnumber of throttle valves

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

Multiple throttle valves are merged onto a single common rotary axis, allowing them to be driven simultaneously by a single actuator. This combining approach maintains the ability to control exhaust flow from multiple cylinders while reducing the number of independent control mechanisms and simplifying the overall system structure.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A single rotary axis serves multiple functions by simultaneously driving multiple throttle valves in different independent passages. This multi-functional design allows one component to perform the work of what would otherwise require multiple separate actuators, reducing system complexity while maintaining control capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration enhances the volumetric efficiency of cylinders by 10-20%, improves engine torque at low engine speeds, and reduces the number of parts and costs while minimizing exhaust interference between cylinders.

Implementation Method 1

the exhaust gas flowing down through a throttle portion formed by the throttle valve can provide the ejector effect (suction effect). That is, the speed of the exhaust gas flowing down through the throttle portion is increased

Methodology Applied

Scientific EffectEjector effect (suction effect): Venturi Effect

Data Source

PatentUS8256402B2Exhaust passage structure of multi-cylinder engine

Publication Date: 2012.09.04 MAZDA MOTOR CORP

AI summary

Three or more independent passages are coupled to respective cylinders which are different from each other, and a collective portion where the independent passages collect is provided. An exhaust turbocharger is arranged downstream of the collective portion. Rotary throttle valves are arranged respectively in the independent passages upstream of the collective portion. At least two of the throttle valves are supported by a common rotary axis. The independent passages with the throttle valves supported by the common rotary axis are coupled to cylinders which have exhaust strokes which are not adjacent to each other. Accordingly, the exhaust gas can be supplied to the exhaust turbocharger efficiently.