Engine Speed Control via Downshifting on Downhill Braking
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Solution Overview
Problem
Heavy-duty vehicles face challenges in controlling engine speed while driving downhill, leading to excessive reliance on service brakes, which can cause wear and reduce longevity, as auxiliary brakes provide insufficient power at higher gears.
Innovation Solution
A computer system that determines the utilization rate of service brakes and, if exceeding a threshold, controls a downshift to increase auxiliary brake power, thereby reducing service brake use and optimizing brake wear by activating service brakes strategically before downshifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the vehicle uses auxiliary brakes to control speed downhill, then service brake wear is reduced, but auxiliary brake power is insufficient at higher gears to prevent exceeding maximum engine speed
Solution Approach 1:
The system dynamically adjusts gear selection based on real-time evaluation of auxiliary brake sufficiency. When auxiliary brakes become insufficient (indicated by excessive service brake utilization), the system automatically selects a lower gear to increase auxiliary brake effectiveness, thereby reducing service brake wear while maintaining adequate braking power.
Solution Approach 2:
The system continuously monitors service brake utilization and compares it against threshold values. This feedback mechanism triggers automatic gear downshifting when service brake usage exceeds the threshold, creating a closed-loop control system that adapts gear selection to actual braking requirements and minimizes service brake wear.
2Power
If the vehicle downshifts to increase auxiliary brake power, then service brake utilization is reduced, but vehicle speed decreases
Solution Approach 1:
The system performs downshifting only partially - specifically when service brake utilization exceeds a predetermined threshold. This partial action approach maintains higher vehicle speeds by avoiding unnecessary downshifts, while still providing sufficient auxiliary brake power to reduce service brake wear when actually needed.
Solution Approach 2:
The system changes the gear ratio parameter dynamically based on service brake utilization levels. By adjusting this single parameter (gear selection), the system simultaneously optimizes both auxiliary brake power availability and vehicle speed maintenance, achieving a balance between the two conflicting objectives.
3Speed
If the vehicle maintains current gear to preserve speed, then auxiliary brake power remains insufficient, but service brakes experience increased wear
Solution Approach 1:
The system enables the vehicle to self-regulate its gear selection based on real-time braking requirements. By automatically monitoring service brake utilization and triggering downshifts when necessary, the system allows the vehicle to service itself, reducing service brake wear through intelligent gear management without requiring external intervention.
Solution Approach 2:
The system takes preliminary action by proactively downshifting before service brake wear becomes excessive. By predicting when auxiliary brakes will become insufficient and downshifting in advance, the system prevents excessive service brake utilization and extends service brake life before wear problems occur.
Data Source
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Figure 2
AI summary
A computer system (100) is provided, comprising processing circuitry (102) configured to: determine that an auxiliary brake power is insufficient to prevent a vehicle (1) running along a downhill road segment from exceeding a maximum engine speed, determine a utilization rate of one or more service brakes (7) of the vehicle (1) to prevent the vehicle (1) from exceeding the maximum engine speed along the downhill road segment, determine that the utilization rate exceeds a predetermined threshold, and based on the utilization rate exceeding the predetermined threshold, control a downshift of the vehicle (1) to increase the auxiliary brake power.