Auxiliary Throttle Series Venturi Engine Airflow Control
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Solution Overview
Problem
Existing fuel vapor canister purge systems face inefficiencies during engine idle conditions due to restricted purge flow, leading to vapor buildup and reduced purging efficiency, particularly when the fuel vapor canister effluent is rich or lean, and the main throttle's wear is increased by frequent adjustments.
Innovation Solution
A method involving coordinated control of a main intake throttle, a canister purge valve, and an auxiliary throttle arranged in series with a venturi, where the canister purge valve is progressively opened first, followed by the auxiliary throttle, and then the main throttle to achieve desired intake manifold pressure, reducing throttle jitter and enhancing purging efficiency by maintaining a leaner state within the canister.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the canister purge valve opening is increased to improve purging efficiency, then vapor removal from the canister is enhanced, but intake manifold vacuum decreases and engine idle speed becomes unstable
Solution Approach 1:
The system divides the airflow control into three separate controllable elements: the canister purge valve, the auxiliary throttle, and the main throttle. By segmenting the flow control, the system can independently optimize purging efficiency while maintaining intake manifold vacuum stability through coordinated adjustment of all three components rather than relying on a single valve.
Solution Approach 2:
The system implements dynamic coordinated control where the canister purge valve, auxiliary throttle, and main throttle are adjusted simultaneously based on real-time engine operating conditions. This dynamic adjustment allows the system to maintain optimal purging efficiency while compensating for vacuum changes and idle speed fluctuations, resolving the contradiction between purging performance and vacuum stability.
2Ease of operation
If the main throttle is frequently adjusted to control purge flow, then purge flow is regulated, but throttle wear increases
Solution Approach 1:
The system segments the throttle control function by introducing an auxiliary throttle that shares the load with the main throttle. The auxiliary throttle handles a portion of the airflow regulation during purging operations, reducing the frequency and intensity of adjustments required by the main throttle and thereby decreasing wear on this critical component.
Solution Approach 2:
The auxiliary throttle acts as an intermediary flow control element between the canister purge valve and the main throttle. It mediates the airflow during purging operations, absorbing some of the control burden and reducing the mechanical stress and wear on the main throttle while still enabling effective purge flow regulation.
3Reliability
If purge flow is restricted to maintain idle speed stability, then idle conditions are maintained, but vapor buildup in the canister increases
Solution Approach 1:
The system employs dynamic coordinated control of the canister purge valve, auxiliary throttle, and main throttle that adjusts all three components simultaneously based on real-time engine conditions. This allows the system to maintain idle speed stability while dynamically optimizing purge flow rate, preventing vapor buildup without compromising idle performance.
Solution Approach 2:
The system changes multiple flow control parameters simultaneously by adjusting the opening degrees of the canister purge valve, auxiliary throttle, and main throttle in coordination. This multi-parameter adjustment enables the system to maintain idle speed stability while increasing overall purge flow capacity, resolving the contradiction between stability and productivity.
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 approach increases the frequency and amount of air drawn through the fuel vapor canister, maintaining a leaner state and reducing throttle wear by minimizing main throttle jitter, while ensuring efficient purging and maintaining desired air mass flow rates.
Implementation Method 1
an auxiliary throttle arranged in parallel with the main throttle and in series with a venturi
Implementation Method 2
the vaporized hydrocarbons (HCs) are stored in a fuel vapor canister packed with an adsorbent which adsorbs and stores the vapors
Data Source
AI summary
Methods and systems are provided for progressively opening and controlling each of a fuel vapor canister purge valve (CPV), an auxiliary throttle coupled in series with a venturi, and a main intake throttle arranged in parallel with the auxiliary throttle in order to deliver a desired intake airflow or manifold vacuum to an engine intake manifold. In one example, a method may include actuating a CPV to supply airflow to the engine via a fuel vapor canister while holding closed a main throttle and an auxiliary throttle arranged in parallel with the main throttle and in series with a venturi. The method further includes progressively opening the CPV, then the auxiliary throttle, and then the main throttle to achieve a desired intake manifold pressure.