Automatic Transmission Gear Selection Using Grade and Payload Estimation
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Solution Overview
Problem
Existing heavy machinery with automatic transmissions face challenges in efficiently managing gear shifts under varying conditions such as different road grades and payloads, leading to suboptimal power delivery and fuel efficiency.
Innovation Solution
A system that uses a programmed processor to iteratively calculate vehicle mass and grade parameters from propulsive and resistive forces, triggering a pre-configured shift control schedule to maintain maximum power output during deceleration by implementing early downshifts when high resistance is encountered, such as climbing steep grades or carrying heavy loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional transmission control is used without grade and payload estimation, then the control system is simpler, but power delivery consistency and fuel efficiency deteriorate under varying road grades and payloads
Solution Approach 1:
The system uses feedback from engine speed, vehicle speed, and throttle position sensors to continuously monitor operating conditions and adjust transmission gear selection accordingly. The controller compares actual operating parameters with expected values and modifies shift timing to maintain optimal power delivery across varying road grades and payload conditions.
Solution Approach 2:
The system performs preliminary estimation of road grade and payload mass using sensor data before actual gear shifts occur. By calculating expected grade and mass conditions in advance, the system can proactively adjust transmission control parameters to maintain power consistency, rather than reacting after performance degradation occurs.
2Power
If early downshifts are implemented to maintain maximum power output during deceleration on steep grades, then power delivery consistency improves, but fuel consumption increases due to earlier engagement of lower gears
Solution Approach 1:
The system dynamically adjusts transmission control based on real-time estimation of road grade and vehicle mass. Rather than using fixed shift schedules, the controller continuously adapts shift timing and gear selection to current operating conditions, allowing early downshifts only when actually needed on steep grades with heavy payloads, rather than under all deceleration conditions.
Solution Approach 2:
The system changes control parameters (shift timing, gear selection) based on varying operating conditions. By estimating road grade and payload mass, the controller adjusts transmission control parameters dynamically, implementing early downshifts only when the estimated grade and mass indicate high resistance conditions, thereby maintaining power consistency without unnecessary fuel consumption during light-load deceleration.
3Adaptability or versatility
If transmission control is adjusted based on estimated road grade and vehicle mass, then adaptability to different operating conditions improves, but measurement precision requirements increase
Solution Approach 1:
The system uses readily available sensor data (engine speed, vehicle speed, throttle position) as intermediaries to indirectly estimate road grade and vehicle mass. Rather than requiring direct sensors for grade and mass, the controller calculates these parameters from measurements that are already part of the engine control system, reducing measurement precision requirements while maintaining adaptability.
Solution Approach 2:
The system uses existing sensor infrastructure and control parameters to self-determine road grade and payload mass conditions. By leveraging data already collected for engine management (throttle position, vehicle speed, engine load), the transmission control system derives grade and mass estimates without requiring additional measurement systems, thereby maintaining adaptability while minimizing measurement precision demands.
Data Source
AI summary
A vehicle includes an automatic transmission and a set of sensor inputs providing values indicating a current operational status of the vehicle pertinent to controlling the automatic transmission. The set of sensor inputs include: engine speed, engine torque, current transmission gear; and vehicle speed. The vehicle includes a programmed processor configured to iteratively and co-dependently generate a vehicle mass parameter value and a grade of incline parameter value. The programmed processor, when generating the vehicle mass parameter value and the grade of incline parameter value, uses a set of parameters including: a propulsive force driving the vehicle; a set of forces acting on the vehicle resisting forward movement, and an observed rate of change of a speed of the vehicle.