Vehicle Control Device Torque Restoration Dynamics
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Solution Overview
Problem
In cylinder deactivatable engines, the difference in combustion intervals between all-cylinder and reduced-cylinder operations leads to inconsistencies in vehicle attitude control, causing a 'strangeness' in driver feedback due to delayed responsivity in torque restoration during vehicle cornering, especially at low engine speeds.
Innovation Solution
A control device that adjusts the rate of change in engine torque restoration based on the number of deactivated cylinders and engine speed, ensuring adequate responsivity by setting larger change rates during reduced-cylinder operations and low engine speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If reduced-cylinder operation is performed to improve fuel economy, then fuel consumption is reduced, but the combustion interval increases causing delayed torque restoration and deteriorated responsivity
Solution Approach 1:
The patent applies dynamics by making the torque change rate adjustable based on operating conditions. The control device dynamically switches between a first torque change rate (for all-cylinder operation) and a second torque change rate (for reduced-cylinder operation), allowing the system to adapt its response characteristics to the current cylinder operation mode and engine speed conditions.
Solution Approach 2:
The patent changes the torque change rate parameter based on cylinder operation mode and engine speed. When reduced-cylinder operation is detected, the control device selects a different torque change rate from storage, effectively changing this critical parameter to compensate for the increased combustion interval and maintain appropriate responsivity.
2Speed
If the torque change rate is increased during reduced-cylinder operation to improve responsivity, then torque restoration speed is improved, but engine torque fluctuations increase
Solution Approach 1:
The control device dynamically adjusts the torque change rate based on real-time detection of cylinder operation mode and engine speed. By switching between predetermined torque change rates stored in memory, the system optimizes the balance between responsivity and torque stability for each operating condition.
Solution Approach 2:
The patent stores multiple torque change rate parameters in advance and selects the appropriate one based on the current operating mode. This parameter switching strategy allows the system to use higher torque change rates when needed for responsivity while using lower rates when stability is prioritized, preventing excessive torque fluctuations.
3Device complexity
If a fixed torque change rate is used for all operating modes, then control simplicity is maintained, but responsivity varies inconsistently between all-cylinder and reduced-cylinder operations
Solution Approach 1:
The control system dynamically selects the appropriate torque change rate based on the detected cylinder operation mode and engine speed. This dynamic adaptation ensures consistent vehicle attitude control characteristics across different operating modes without requiring complex real-time calculations, maintaining reasonable system simplicity.
Solution Approach 2:
The patent implements parameter changes by storing multiple torque change rate values in advance and selecting the appropriate one based on operating conditions. This approach maintains control consistency and reliability across different cylinder operation modes while avoiding the need for complex real-time parameter optimization algorithms.
Data Source
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AI summary
A control device for a vehicle includes: an engine (10); an engine torque adjustment mechanism; and a PCM (50) configured to execute vehicle attitude control for, upon satisfaction of a vehicle attitude control executing condition that the vehicle is traveling and a steering angle-related value is increasing, reducing the engine torque to thereby generate deceleration of the vehicle. The PCM (50) is configured, upon satisfaction of a given terminating condition for terminating the vehicle attitude control, to control the engine torque adjustment mechanism to restore the reduced engine torque to an original state before the execution of the vehicle attitude control. The PCM (50) sets a rate of change in the engine output torque being restored, such that it becomes larger as the number of times of combustion per unit time becomes smaller, and restores the engine torque according to the rate of change set in the above manner.