Hybrid Vehicle Engine Start Control for Relay Arcing Prevention
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Solution Overview
Problem
In hybrid electric vehicles, the relay connected to the electric motor and high-voltage storage device is at risk of fusion due to arcing when the engine is started by the starter, especially if the electric motor fails to crank the engine, leading to potential engine start delays and uncomfortable driving experiences.
Innovation Solution
A control apparatus that detects electric motor failure and suspends engine start attempts using the electric motor, instead initiating engine starts using the starter while keeping the relay open to prevent arcing and ensure reliable engine starting, with a memory component to track motor failure and a reset control for managing voltage levels to prevent relay fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is started by the starter with the relay closed, then the engine can be cranked and started, but the relay may be fused due to arcing phenomenon
Solution Approach 1:
The control apparatus detects electric motor failure before attempting engine start with the starter. When failure is detected, the relay is opened in advance before starter activation, preventing the arcing phenomenon that would occur if the relay remained closed during starter operation. This preliminary opening of the relay eliminates the harmful effect while maintaining engine start capability.
2Object-affected harmful factors
If the relay is opened to prevent arcing, then relay fusion is avoided, but the electric motor cannot be used for engine starting
Solution Approach 1:
The control apparatus incorporates a detection mechanism that monitors electric motor status and provides feedback on failure conditions. Based on this feedback, the system intelligently decides whether to open the relay before starter activation. When electric motor failure is detected, the relay is opened; when no failure is detected, the relay remains closed, allowing the electric motor to be used for engine starting. This feedback-based control maintains adaptability while preventing relay fusion.
3Adaptability or versatility
If the electric motor is used to start the engine, then the relay remains closed and arcing risk increases, but the electric motor provides a starting option
Solution Approach 1:
The system continuously monitors electric motor health status and uses this feedback to determine the safe operating mode. When the electric motor is healthy, the relay remains closed and the electric motor can be used for starting. When failure is detected, the system switches to starter-only operation with the relay opened. This feedback mechanism allows the system to maximize electric motor usage while preventing arcing damage.
Solution Approach 2:
When electric motor failure is detected, the system extracts the faulty electric motor from the engine starting process and relies solely on the starter. The relay is opened to isolate the high-voltage circuit, removing the source of potential arcing. This extraction of the failed component maintains engine starting capability through the alternative starter mechanism while eliminating the harmful arcing risk.
Data Source
AI summary
A control apparatus for a hybrid electric vehicle including an engine, a starter and an electric motor that is connected to an electric storage device through a relay. The control apparatus executes an engine start control to crank and start the engine by using a selected one of the starter and the electric motor. The control apparatus detects presence or absence of failure of the electric motor, when executing the engine start control by using the electric motor with the relay being closed. When detecting the failure of the electric motor, the control apparatus causes the relay to be opened, and to suspend execution of the engine start control by using the electric motor, and is configured, when start of the engine is requested next, to execute the engine start control by using the starter while keeping the relay to be opened.