Vehicle Control Device Voltage Threshold Engine Start
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Solution Overview
Problem
In vehicles, the drive voltage required to start the engine may differ from the drive voltage needed to operate mechanisms like transmissions or braking systems, leading to potential control issues if the engine starts but these mechanisms cannot be driven, compromising vehicle control.
Innovation Solution
A control device that includes an engine starting unit, an engine control unit, and a transmission control unit, which ensures the engine only starts when the battery voltage meets a higher second drive voltage threshold, preventing engine start if the transmission voltage is insufficient, thus ensuring safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine starting unit is designed to start the engine with a lower first drive voltage, then the engine can be started even when battery voltage is low, but the transmission and other mechanisms cannot be driven because they require a higher second drive voltage
Solution Approach 1:
The transmission control unit checks the battery voltage and sends an engine start permission signal to the engine control unit before the engine starting unit is activated. This preliminary voltage verification ensures that the battery has sufficient voltage (second drive voltage or higher) to power both the engine and transmission, preventing the scenario where the engine starts but the transmission cannot be driven.
2Measurement precision
If the transmission control unit continuously updates the voltage value at predetermined time intervals, then the voltage monitoring is accurate and responsive, but the system complexity and processing load increase
Solution Approach 1:
The transmission control unit updates the voltage value at predetermined time intervals rather than continuously. This periodic updating approach maintains adequate voltage monitoring accuracy while reducing the processing load and system complexity compared to continuous monitoring, achieving a balance between measurement precision and device complexity.
Data Source
AI summary
A control device includes an engine starting unit that starts an engine on a condition that a first voltage is supplied, an engine control unit that controls an operation of the engine starting unit, and a transmission control unit that drives a transmission on a condition that a second voltage, which is higher than the first voltage, is supplied. The transmission control unit sends an engine start permission signal to the engine control unit in a case where a voltage of power supplied from a battery is the second voltage or higher, and the engine control unit permits the engine starting unit to start the engine on a condition that the engine control unit receives the engine start permission signal.