Engine Purge System Using Supercharger Pressure Differential
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Solution Overview
Problem
Existing purge systems for internal combustion engines face challenges with increased electric power consumption, installation space, and costs when using electric pumps, and insufficient purge quantity due to low negative pressure from supercharging devices.
Innovation Solution
A purge system that utilizes pressure differences between the upstream and downstream sides of a supercharging device to desorb fuel vapor from an adsorbent in a canister, eliminating the need for an electric pump, and effectively controls valve operations to ensure sufficient purge quantity across various engine operational states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an electric pump is provided in the purge passage to purge fuel vapor, then the purge function is improved, but electric power consumption increases
Solution Approach 1:
The invention extracts and removes the electric pump from the purge system, replacing it with a valve-based control mechanism that utilizes existing pressure differentials in the intake air passage to achieve fuel vapor purge without additional energy consumption
Solution Approach 2:
The system utilizes the natural negative pressure generated by the engine's intake operation and supercharging device to drive the purge process, eliminating the need for external power sources and making the system self-sufficient
2Productivity
If an electric pump is provided in the purge passage, then the purge function is improved, but installation space increases
Solution Approach 1:
The electric pump is completely removed from the system and replaced with electronically controlled valves that are integrated into the existing fuel vapor passage structure, significantly reducing the space required for the purge system
3Use of energy by moving object
If the negative pressure from supercharging device is used to purge fuel vapor, then power consumption is reduced, but purge quantity becomes insufficient
Solution Approach 1:
The system dynamically switches between two purge modes: utilizing negative pressure from the supercharging device during supercharging operations, and switching to positive pressure from a pressure generation device during non-supercharging operations, ensuring sufficient purge quantity under all operating conditions
Solution Approach 2:
The invention changes the pressure parameter used for purge based on operating conditions - using negative pressure during supercharging and positive pressure during normal operation, thereby maintaining effective purge quantity across different engine states
4Ease of operation
If a purge control valve and electric pump are placed in the purge passage, then purge control is improved, but device complexity increases
Solution Approach 1:
The electric pump is removed from the purge passage, simplifying the system structure while maintaining purge control functionality through electronically controlled valves that regulate flow based on pressure differentials
Solution Approach 2:
The system uses pressure differential-based flow control through valves, utilizing the natural pressure variations in the intake air passage and fuel vapor passage to achieve effective purge control without mechanical pumps
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
The system achieves a sufficient purge quantity without additional devices, reducing power consumption and costs, and effectively desorbs fuel vapor using pressure differences, ensuring efficient operation during both supercharging and non-supercharging periods.
Implementation Method 1
the fuel vapor is supplied from the fuel tank into a canister, which contains an adsorbent to temporarily adsorb the fuel vapor
Implementation Method 2
The negative pressure, which is generated in an intake air pipe during an operation of the engine, is used to desorb the fuel vapor from the adsorbent
Data Source
AI summary
A canister is connected with a fuel tank to adsorb fuel vapor generated in the fuel tank. The canister is also connected to a downstream side point of an intake air pipe, which is on a downstream side of a supercharging device, through a first purge line. The canister is also connected to an upstream side point of the intake air pipe, which is on an upstream side of the supercharging device, through a second purge line. An ECU opens a first valve of the first purge line and a second valve of the second purge line to generate an air flow through the first connection passage, the canister and the second connection passage to desorb the fuel vapor from the adsorbent and to purge the desorbed fuel vapor into the intake air passage in an operational period of the supercharging device.