Engine Starting Apparatus with Inter-Relay Switch for Low Voltage
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Solution Overview
Problem
Existing engine starting systems face challenges in reliably starting a vehicle engine when the battery voltage drops below a certain threshold, causing the microcomputer to reset and leading to uncontrollable relays, especially during normal engine start operations, which can result in failed engine starts.
Innovation Solution
An engine starting apparatus that includes a relay control section and an inter-relay switch, allowing the system to operate even when the battery voltage is low by making electrical connections between relays to ensure the starter motor receives the necessary voltage for engine start, independent of the microcomputer's control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the microcomputer individually controls the solenoid relay and motor relay to improve starter quietness and durability, then the engine can be restarted reliably after idle stop, but the system fails when battery voltage drops below the lower limit during normal engine start
Solution Approach 1:
The patent divides the relay control into two independent paths: (1) microcomputer-controlled relays for idle stop restart operations, and (2) switch-controlled relays for normal engine start operations. This segmentation allows each control path to be optimized for its specific operating conditions, resolving the contradiction between reliability during idle stop and adaptability during normal start.
Solution Approach 2:
The patent introduces a switch as an intermediary component that can directly control the relays independently of the microcomputer. This intermediary control mechanism ensures that relay operation is not dependent on microcomputer functionality, allowing the system to operate reliably even when battery voltage drops below the microcomputer's operational threshold.
2Reliability
If the battery voltage drops below 6V during normal engine start, then the microcomputer resets to prevent malfunction, but the relays become uncontrollable and engine start fails
Solution Approach 1:
The control system is segmented into microcomputer-controlled functions and switch-controlled functions. The switch-controlled relay path operates independently of the microcomputer, ensuring that engine start operation remains accessible even when the microcomputer resets due to low voltage.
Solution Approach 2:
The switch and relay circuitry are designed to function autonomously without microcomputer intervention. The switch can directly activate the relays and starter motor, allowing the system to self-start the engine even when the microcomputer is non-functional due to battery voltage below 6V.
3Reliability
If a voltage step-up circuit is added to prevent microcomputer reset during low voltage, then the control-use voltage can be maintained, but the manufacturing cost increases
Solution Approach 1:
The patent extracts the critical engine start function from the microcomputer-controlled system and places it in a simple switch-controlled circuit. This extraction eliminates the need for expensive voltage step-up circuits, as the switch-controlled relays can operate directly from the battery voltage without requiring the microcomputer to maintain stable operation.
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
Enables reliable engine starting even when battery voltage is low, preventing microcomputer resets and ensuring consistent operation without the need for additional voltage step-up circuits, thus improving reliability and reducing manufacturing costs.
Implementation Method 1
a solenoid relay for operating the pinion-engagement controlling solenoid and a motor relay for operating a starter motor are individually controlled by the ECU
Implementation Method 2
The power supply circuit generates a control-use voltage at a constant level (5V, for example) from the battery voltage
Data Source
AI summary
The engine starting apparatus operates on battery voltage when the battery voltage is higher than a predetermined voltage to control starting of an engine of a vehicle. The engine starting apparatus includes a relay control section configured to output a drive signal individually to first and second relays of a starter of the vehicle engine to drive the first and second relays when predetermined engine start conditions are satisfied, the starter being configured to operate when the first and second relays are driven, and an inter-relay switch configured to make electrical connection between the first and second relays when the first relay is applied with the battery voltage, the second relay being applied with the battery voltage when the electrical connection is made. The first relay is configured to be applied with the battery voltage when a manual start switch is operated.