Dynamic Braking Chopper Monitoring to Prevent Vehicle Engine Stall
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Solution Overview
Problem
Off-highway vehicles face engine stalling issues when transitioning from dynamic braking to propel mode due to defective or abnormal braking choppers, which can lead to power demand overload on the engine, causing engine stall and disrupting vehicle operations.
Innovation Solution
A control system equipped with a current sensor and processors that monitor the current through the resistor leg, detecting abnormal conditions and generating a control signal to increase engine speed before transitioning to the propel mode, thereby mitigating the risk of engine stall and overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine speed is reduced to a reduced idle speed during dynamic braking mode to conserve fuel, then fuel efficiency is improved, but the engine may not be able to handle a significant power demand when transitioning to propel mode, causing engine stalling
Solution Approach 1:
The control system performs preliminary detection of braking chopper status during dynamic braking mode before transitioning to propel mode. By identifying abnormal braking choppers in advance, the system can prepare the engine by increasing its speed from reduced idle speed to a higher operating speed, ensuring the engine can handle the upcoming power demand without stalling.
Solution Approach 2:
The system continuously monitors the status of braking choppers and provides feedback to the engine control. When an abnormal braking chopper is detected, the feedback triggers an engine speed adjustment, creating a closed-loop control system that adapts engine operation to the actual braking system condition, thereby preventing engine stalling while maintaining fuel efficiency during normal operation.
2Reliability
If a braking chopper is defective or abnormal (stuck in conducting state), then the braking chopper fails to provide sufficient resistance, but increasing engine speed continuously would consume excessive fuel
Solution Approach 1:
The system detects abnormal braking choppers during dynamic braking mode and increases engine speed only when necessary, before transitioning to propel mode. This preliminary action avoids continuous engine speed maintenance at high levels, reducing unnecessary fuel consumption while ensuring engine stability when needed.
Solution Approach 2:
The engine speed is dynamically adjusted based on the detected braking chopper status and the anticipated transition to propel mode. The system increases engine speed from reduced idle speed to a higher operating speed only when an abnormal braking chopper is detected and transition is anticipated, rather than maintaining a constantly high speed, thereby optimizing the balance between reliability and fuel consumption.
3Reliability
If the engine speed is increased to prevent engine stalling, then engine stability is improved, but fuel efficiency during dynamic braking mode deteriorates
Solution Approach 1:
The control system increases engine speed only as a preliminary action before transitioning from dynamic braking mode to propel mode when an abnormal braking chopper is detected. During the dynamic braking mode itself, the engine maintains reduced idle speed for fuel efficiency, and the speed increase is temporarily applied only when needed to ensure stable transition and 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
The system effectively prevents engine stalling and alternator collapse by increasing engine speed in response to abnormal braking chopper conditions, ensuring stable vehicle operation and maintaining fuel efficiency during dynamic braking mode.
Implementation Method 1
a current sensor configured to be disposed onboard a vehicle and to monitor a measured current conducted into a resistor leg of the vehicle
Implementation Method 2
The electrical energy generated during dynamic braking is typically dissipated from the vehicle as heat through retarding grids of resistors and insulators
Implementation Method 3
the traction motors which transform the electrical energy back into mechanical energy to drive the wheels during a propel mode of operation
Implementation Method 4
The alternator converts mechanical energy into electrical energy that is transmitted to the traction motors
Data Source
Figure 1~3
Figure 2
Figure 4
AI summary
A control system includes a current sensor (222) and one or more processors (220). The current sensor is configured to be disposed onboard a vehicle (100) and to monitor a measured current conducted into a resistor leg (214) of the vehicle. The resistor leg has a braking chopper (216) and one or more resistive elements (218), and is connected with a traction bus (208) of the vehicle. The one or more processors are configured to receive the measured current from the current sensor and, in response to the measured current differing from an expected current through the resistor leg, the one or more processors are configured to generate a control signal configured to one or more of increase an engine speed of an engine of the vehicle, increase cooling to the one or more resistive elements of the resistor leg, restrict movement of the vehicle, or schedule maintenance for the resistor leg.