Automatic Transmission Engine Speed Control for Fuel Efficiency
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Solution Overview
Problem
In vehicles with automatic transmissions, the engine often gets 'stuck' at high, inefficient rotational speeds during uphill driving, leading to increased fuel consumption due to the inability to upshift gears efficiently, as the engine struggles to reach the necessary speed for torque production.
Innovation Solution
A method that senses current engine rotational speed and increase, estimates the necessary upshift speed, and automatically controls engine torque to decrease the speed to a more efficient level when the engine cannot reach the upshift speed, optimizing gear shifts and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine rotational speed is increased to reach the minimum upshift speed for gear upshift, then the gear upshift can be performed, but the engine operates at high rotational speeds with low efficiency and increased fuel consumption
Solution Approach 1:
The control unit performs preliminary estimation to predict whether the engine can reach the minimum upshift rotational speed before actually attempting the upshift. This preliminary assessment allows the system to avoid unnecessary high-speed operation by predicting potential upshift failures in advance, thereby preventing fuel waste while maintaining reliable upshift capability when feasible.
Solution Approach 2:
The control unit continuously monitors engine rotational speed, acceleration, and other parameters to detect when the engine is struggling to reach the minimum upshift speed. This feedback mechanism enables real-time adjustment of upshift timing and engine speed management, optimizing the balance between achieving successful upshifts and minimizing fuel consumption during the process.
2Use of energy by moving object
If the engine rotational speed is limited to efficient operating ranges, then fuel consumption is reduced, but the engine may not reach the necessary speed for successful gear upshift
Solution Approach 1:
The control unit performs preliminary estimation before upshift to predict whether the engine can successfully reach the minimum upshift rotational speed. This advance prediction allows the system to plan engine speed management strategies that minimize fuel consumption while ensuring successful upshifts when conditions permit, resolving the contradiction between efficiency and reliability.
Solution Approach 2:
The system dynamically adjusts engine speed management strategies based on real-time conditions. The control unit modifies upshift timing and engine speed targets adaptively, allowing the engine to operate efficiently in normal conditions while providing the necessary speed increases when upshift success requires it, thus balancing fuel economy with reliable gear changing capability.
3Reliability
If the transmission control unit waits for the engine to naturally reach upshift speed, then the upshift can be performed, but the engine remains stuck at high rotational speeds causing increased fuel consumption
Solution Approach 1:
The control unit performs preliminary estimation to predict upshift success before execution. This allows the system to proactively manage engine speed rather than passively waiting, enabling timely intervention to prevent the engine from lingering at inefficient high speeds, thus reducing time loss and fuel consumption while ensuring reliable upshift execution.
Solution Approach 2:
The control unit continuously monitors engine acceleration and rotational speed to detect when the engine is failing to reach the minimum upshift speed. This feedback triggers active upshift execution rather than passive waiting, reducing the time the engine spends at inefficient speeds and minimizing fuel consumption while maintaining reliable gear changing.
Data Source
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AI summary
A method for a more efficient use of a vehicle combustion engine during driving, said vehicle comprising an automatic step geared transmission, said method comprising the steps of : - sensing current engine rotational speed and engine rotational speed increase, - estimating necessary minimum upshift engine rotational speed for a coming gear upshift; - registering that the engine rotational speed stops increasing without reaching said minimum upshift engine rotational speed, and where said engine rotational speed stops increasing relatively close to a maximum engine rotational speed where engine efficiency is relatively low and, - automatically controlling engine output torque in order to limit the engine rotational speed to a first predetermined engine speed where engine efficiency is relatively high.