Transport Refrigeration Engine Start Under Low Battery Voltage
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Solution Overview
Problem
Transport refrigeration systems face challenges in starting an electronically controlled engine when the battery supply voltage is low, especially in extreme cold weather or with poor battery conditions, leading to incomplete engine starts due to power interruption during the pre-crank state.
Innovation Solution
The system employs an engine control unit (ECU) with a TRS controller that continuously supplies power to the engine starter by maintaining the keyswitch and run signals active through CAN message transmission, ensuring the engine can start completely even with low voltage supply by keeping the switches closed until the startup is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery supplies power to the engine starter during pre-crank state with low voltage, then the engine can be started in cold weather or with poor battery conditions, but the battery may stop providing power causing incomplete engine start
Solution Approach 1:
The system performs preliminary detection of low voltage conditions before the engine start is complete. The controller monitors voltage during the pre-crank and crank states, and when low voltage is detected, it proactively extends the crank command to ensure the engine completes startup even if voltage drops during the process. This preliminary detection and proactive response prevents incomplete engine starts.
Solution Approach 2:
The system maintains continuous power supply to the starter motor by continuously transmitting the crank command signal throughout the entire startup process when low voltage conditions are detected. Instead of allowing the power supply to interrupt, the controller ensures uninterrupted command transmission from pre-crank through crank completion, maintaining the continuity of the useful action (engine starting) despite battery voltage limitations.
2Reliability
If the ECU receives a reset instruction during engine startup, then the ECU can be protected from voltage fluctuations, but the engine startup process may be interrupted
Solution Approach 1:
The system detects low voltage conditions preliminarily before they cause ECU reset. By monitoring voltage during the pre-crank state and detecting low voltage beforehand, the controller can prepare to extend the crank command continuously, preventing ECU reset from interrupting the startup process. This preliminary detection allows the system to maintain startup continuity even when voltage fluctuations occur.
3Loss of energy
If the battery voltage is low during engine startup, then energy consumption is reduced, but the engine cannot complete the startup process
Solution Approach 1:
The system maintains continuous crank command transmission throughout the entire startup process when low voltage conditions are detected. By continuously commanding the starter motor to operate from pre-crank through crank completion without interruption, the system ensures the engine completes startup despite limited battery voltage. This continuous action approach prioritizes successful engine start completion over energy conservation during the critical startup phase.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Embodiments of systems and methods for starting an electronically controlled engine of a TRS by supplying power from a battery, are provided. The engine is electronically controlled by an engine control unit (ECU). The systems and methods can achieve a complete engine start even when the ECU experiences a reset during the startup of the engine.