Engine Torque Control via Dynamic Time Constant Segmentation
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Solution Overview
Problem
Existing torque-based engine control methods face challenges in accurately controlling engine torque, particularly when the torque trajectory is complex, leading to issues like fuel efficiency deterioration, increased exhaust temperature, and torque fluctuations due to adaptation errors and individual variations in the engine control system.
Innovation Solution
An engine control device that calculates target torque using an estimated torque, which performs primary delay processing on the target torque with a primary delay coefficient equivalent to a time constant calculated for each control cycle based on the change in actual intake air amount, allowing for accurate torque control without requiring adaptation of multiple time constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple time constants are used for torque control adaptation, then torque control accuracy improves, but adaptation complexity and man-hours increase
Solution Approach 1:
The patent segments the torque control into two distinct modes: low-response torque control for steady-state operation and high-response torque control for transient operation. Each mode uses its own time constant (first time constant for low-response, second time constant for high-response), allowing accurate adaptation without requiring multiple overlapping time constants. This segmentation resolves the contradiction by achieving accurate torque control through structured division of control responsibilities.
Solution Approach 2:
The patent dynamically switches between different time constants based on the operating condition. A switching determination unit determines whether to use the first time constant or second time constant based on whether the current state is steady-state or transient. This dynamic adaptation allows the system to achieve accurate torque control across varying conditions without increasing overall system complexity.
2Speed
If high-response torque control is used for complex torque trajectories, then torque response speed improves, but fuel efficiency deteriorates
Solution Approach 1:
The system dynamically selects the appropriate time constant based on operating conditions. During transient states requiring fast response, the second time constant (smaller value) is used for high-response torque control. During steady-state operation, the first time constant (larger value) is used for low-response torque control that maintains fuel efficiency. This dynamic switching resolves the contradiction by optimizing the response characteristics to match actual operational needs.
Solution Approach 2:
The patent implements periodic switching between control modes based on the detection of transient and steady-state conditions. The switching determination unit continuously monitors operating parameters and periodically switches between high-response and low-response control modes, allowing the system to achieve fast torque response only when necessary while maintaining fuel efficiency during normal operation.
3Measurement precision
If torque control adaptation is performed for each engine individual, then control accuracy improves, but adaptation time and complexity increase
Solution Approach 1:
The patent segments the adaptation process into two distinct adaptation routines: one for the first time constant (low-response mode) and another for the second time constant (high-response mode). Each routine adapts its specific time constant based on its own cost function and operating conditions. This segmentation allows parallel or independent adaptation of both time constants, achieving accurate individualized control without requiring sequential adaptation of multiple parameters.
Solution Approach 2:
The patent implements feedback mechanisms where the actual torque is compared with the target torque to generate cost functions. These cost functions guide the adaptation of both time constants independently. The feedback from torque measurement and comparison allows the system to automatically adjust the time constants for each engine individual, achieving accurate adaptation without increasing overall adaptation time.
Data Source
AI summary
For an engine that draws a complicated torque trajectory, it has been taken a lot of time to adapt a time constant for calculation of estimated torque. Therefore, an ECU 102 includes a target torque calculation unit 203 that calculates target torque of an engine for which torque-based engine control is performed using estimated torque, and an estimated torque calculation unit 210 that calculates the estimated torque by calculating a primary delay coefficient 304 equivalent to a time constant calculated for each control cycle based on a change in an actual intake air amount with respect to a target intake air amount of air sucked into the engine and performing primary delay processing on the target torque using the primary delay coefficient 304.