Auxiliary LPG Switch for ISG Vehicle Ignition Control
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Solution Overview
Problem
The existing ignition devices for ISG-equipped vehicles using LPG as fuel face issues in accurately sensing the ON/OFF state of the LPG switch, leading to prolonged operation of the starting motor and inability to diagnose the EFR relay when the LPG switch is in the OFF state, which reduces durability and diagnostic capabilities.
Innovation Solution
An auxiliary LPG switch is introduced, connected to a relay that provides a second external voltage for fuel cut-off solenoid valves, allowing the ECU to accurately determine the ON/OFF state of the LPG switch and implement ISG control, ensuring proper engine restart performance and emergency shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the ECU uses the transistor to sense the ON/OFF state of the LPG switch, then the engine can be automatically started, but the starting motor runs prolonged when the transistor shuts off, reducing durability
Solution Approach 1:
An auxiliary LPG switch is introduced as an intermediary component between the main LPG switch and the ECU. This auxiliary switch directly senses the ON/OFF state and provides accurate signals to the ECU, eliminating the reliance on the transistor that causes prolonged starting motor operation. The auxiliary switch acts as a mediator that ensures the ECU receives correct status information without the interference of the faulty transistor sensing mechanism.
2Extent of automation
If the ECU relies on the transistor to sense LPG switch state, then engine control is implemented, but the EFR relay cannot be diagnosed when LPG switch is OFF
Solution Approach 1:
The auxiliary LPG switch serves as an intermediary sensing component that provides direct feedback to the ECU about the LPG switch state. This separate sensing path enables the ECU to independently determine whether the LPG switch is ON or OFF, allowing proper diagnosis of the EFR relay even when the main LPG switch is in the OFF position. The intermediary auxiliary switch creates an independent detection channel that resolves the diagnostic blind spot.
3Productivity
If the starting motor runs prolonged to restart the engine, then the engine can be restarted, but the durability of the starting motor is reduced
Solution Approach 1:
The auxiliary LPG switch provides accurate real-time feedback to the ECU about the LPG switch ON/OFF state. This reliable feedback mechanism enables the ECU to make timely and accurate decisions about engine starting and stopping, preventing prolonged operation of the starting motor. The feedback from the auxiliary switch ensures the ECU can detect the appropriate moment to stop the starting motor, thereby extending its lifespan while maintaining engine restart capability.
Data Source
AI summary
An ignition device is provided for an idle stop & go system (ISG)-equipped vehicle using a liquefied petroleum gas (LPG) as a fuel. A separately installed auxiliary LPG switch detects the ON/OFF state of the LPG switch, drives fuel cut-off solenoid valves, and switches on/off together with the LPG switch. The ON/OFF state of the LPG switch can be determined based on an output voltage of the auxiliary LPG switch, and then ISG control can be implemented. After the fuel cut-off solenoid valves are driven, the fuel pipeline pressure remains in the state before the idle stop to improve the engine starting performance upon restarting. Also, in an emergency, the LPG and auxiliary LPG switches are simultaneously switched off, the fuel cut-off solenoid valves are quickly switched off and the fuel pump motor is stopped to quickly cut off the fuel supply and prevent a secondary accident in advance.