Purge Pump Rotation Control for Fuel Vapor Flow Regulation
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Solution Overview
Problem
Conventional vaporized-fuel treating apparatuses with simple on-off purge valves cannot accurately regulate purge gas flow rates, leading to air-fuel ratio disturbances in internal combustion engines, which cause fluctuations in the combustion chamber.
Innovation Solution
The apparatus controls the rotation number of the purge pump to adjust the purge gas flow rate to a value equal to or lower than a predetermined upper-limit flow rate, and optionally adjusts the internal combustion engine's rotation number and load ratio, or uses an intake pressure control valve to regulate the intake pressure, ensuring precise flow rate control and preventing air-fuel ratio disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple on-off purge valve is used, then the apparatus structure is simplified, but the flow rate regulation precision deteriorates
Solution Approach 1:
The patent introduces a purge pump as an intermediary device between the canister and intake passage. The pump acts as a mediator that can precisely control the purge gas flow rate through its rotation speed, while the simple on-off valve maintains structural simplicity. This resolves the contradiction by placing the flow rate control function in the pump rather than the valve.
Solution Approach 2:
The patent controls the rotation speed of the purge pump to regulate the purge gas flow rate. By changing the rotational parameter of the pump, precise flow rate control is achieved without requiring a complex regulating valve. This parameter-based control resolves the contradiction between simple valve structure and precise flow rate regulation.
2Manufacturing precision
If the purge valve is controlled under duty control to change purge flow rate, then the flow rate can be regulated, but the apparatus structure becomes more complex
Solution Approach 1:
Instead of controlling the valve to regulate flow rate (conventional approach), the patent inverts the control strategy by using a simple on-off valve and controlling the pump's rotation speed instead. This inversion resolves the contradiction by achieving flow rate control through the pump rather than through complex valve duty control.
Solution Approach 2:
The patent replaces the conventional mechanical flow rate control method (duty-controlled valve) with a rotational speed control method for the purge pump. This substitution allows precise flow rate regulation while maintaining a simple on-off valve structure, resolving the contradiction between control precision and structural simplicity.
3Reliability
If the purge pump rotation number is controlled to adjust actual purge flow rate, then the air-fuel ratio disturbance is prevented, but the control system complexity increases
Solution Approach 1:
The patent employs feedback control by monitoring the actual purge flow rate and adjusting the pump rotation speed accordingly. The control unit receives information about the actual flow rate and modifies the pump rotation to maintain the flow rate within the upper-limit range, preventing air-fuel ratio disturbance. This feedback mechanism ensures reliability while managing control system complexity.
Solution Approach 2:
The control system automatically adjusts the pump rotation speed based on the actual purge flow rate conditions without requiring external manual intervention. The system serves itself by autonomously regulating the flow rate to prevent air-fuel ratio disturbance, resolving the contradiction between reliability and control complexity through automated self-regulation.
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 solution allows for precise regulation of the purge gas flow rate, preventing air-fuel ratio disturbances and simplifying the apparatus structure while maintaining optimal air-fuel ratio control in internal combustion engines.
Implementation Method 1
a purge pump provided in the purge passage
Implementation Method 2
when the vaporized fuel in a canister is to be desorbed and supplied to the intake pipe
Data Source
AI summary
A vaporized-fuel treating apparatus is configured to perform purge control in which a purge valve is placed in an open state while a purge pump is being driven to introduce purge gas from a canister to an intake passage through a purge passage. When an actual value of a flow rate of the purge gas during execution of the purge control is defined as an actual purge flow rate, and an upper-limit value of the purge flow rate to prevent the occurrence of A/F disturbance where A/F in a combustion chamber of an engine excessively fluctuates, as an upper-limit purge flow rate, the number of rotations of the purge pump is controlled during execution of the purge control to adjust the actual purge flow rate to a value equal to or lower than the upper-limit purge flow rate.