Dynamic Torque Reserve Control for Idle Speed Stability
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Solution Overview
Problem
Existing engine control systems face challenges in managing torque reserves effectively, particularly during periods of unknown impending loads, which can lead to inefficient fuel economy and increased torque output when such loads are detected late or not at all.
Innovation Solution
A control system that includes a speed error determination module and a torque reserve module, which periodically assesses the engine speed error rate and adjusts the torque reserve accordingly, maintaining it at a base level when no impending load is detected and increasing it when an impending load is anticipated based on specific conditions such as engine speed, coolant temperature, and vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the torque reserve is maintained at a high level to ensure rapid response to unexpected loads, then the reliability of engine performance is improved, but the fuel economy deteriorates due to unnecessary torque output
Solution Approach 1:
The torque reserve is made dynamic rather than static. The system continuously monitors engine operating conditions (speed, load, temperature) and adjusts the torque reserve level in real-time. When conditions indicate high likelihood of operator demand, the torque reserve increases; when conditions suggest low likelihood, the torque reserve decreases, optimizing the balance between responsiveness and fuel efficiency
Solution Approach 2:
The control system implements feedback mechanisms by monitoring engine operating conditions and comparing them against predetermined thresholds. Based on this feedback, the system dynamically adjusts the torque reserve level. The feedback loop continuously evaluates whether the current torque reserve is appropriate and makes adjustments to maintain optimal performance while minimizing fuel consumption
2Speed
If the torque reserve is increased to improve response time to impending loads, then the speed of engine response is improved, but the fuel economy deteriorates due to sustained high torque output
Solution Approach 1:
The system performs preliminary assessment of operator demand by monitoring engine operating conditions before actual demand occurs. When conditions suggest impending operator demand, the torque reserve is proactively increased in advance, ensuring rapid response capability is ready when needed. This preliminary action avoids the need for sustained high torque reserve during normal operation
Solution Approach 2:
The torque reserve level transitions from a fixed value to a dynamic parameter that adapts to changing operating conditions. The system continuously adjusts the torque reserve based on real-time monitoring of engine speed, load, and temperature, ensuring high response speed only when conditions warrant it while maintaining fuel efficiency during normal operation
Data Source
AI summary
A control system for an engine includes a speed error determination module that periodically determines an engine speed error rate based on a difference between a measured speed and a desired speed of the engine, and a torque reserve module that monitors the engine speed error rate and that selectively adjusts a torque reserve of the engine based on the engine speed error rate. The torque reserve module maintains the torque reserve at a predetermined first torque reserve amount while the engine speed error rate is less than a predetermined first error rate and selectively increases the torque reserve above the first torque reserve amount when the engine speed error rate increases above a predetermined second error rate greater than the first error rate. The torque reserve module decreases the torque reserve when the engine speed error rate decreases below the first error rate. A related method is also provided.