Downshifting Sound Control via Ignition Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for controlling downshifting in automatic transmissions with internal combustion engines fail to adequately compensate for abrupt shifts, particularly in quiet engines, affecting driving comfort, transmission lifespan, and vehicle stability.
Innovation Solution
A method that involves a multi-phase approach to manage downshifting by gradually increasing engine torque, adjusting the ignition timing to create a sporty sound, and selectively blanking engine cylinders to achieve synchronization and enhance acoustic perception, while ensuring torque reserve and synchronization speed are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If intermediate gas is automatically applied during downshifting, then the abrupt shift is reduced and driving comfort is improved, but the downshifting process becomes acoustically insufficient and difficult to perceive
Solution Approach 1:
The patent applies parameter changes by modifying the ignition timing (ignition angle) during the downshifting process. Specifically, in a third phase after the hydraulic down time, the ignition angle is substantially retarded (set later than +5° before top dead center, and preferably after top dead center at -10°). This parameter change generates an acoustically clearly perceivable sporty sound while maintaining the torque buildup necessary for smooth downshifting.
Solution Approach 2:
The patent implements periodic action through multi-phase control of the downshifting process. The downshift is divided into distinct phases: first phase (hydraulic down time with slow torque increase), second phase (throttle valve opening with fast torque buildup), and third phase (late ignition timing for acoustic enhancement). This periodic structuring allows the system to achieve both smooth transition and acoustic perceptibility at different time intervals.
2Difficulty of detecting and measuring
If the ignition angle is substantially retarded to generate sporty sound, then acoustic perceptibility is improved, but additional torque reserve is required which may affect shifting speed
Solution Approach 1:
The patent applies preliminary action by building up torque reserve during the second phase (first regulation phase) before implementing the late ignition timing in the third phase. The system ensures that sufficient torque reserve is available beforehand to support both the acoustic enhancement and maintain fast shifting performance, thereby resolving the contradiction between sound generation and shifting speed.
Solution Approach 2:
The patent implements dynamics by adaptively adjusting the ignition timing based on the phase of the downshifting process. The ignition angle is dynamically retarded during the third phase when acoustic perceptibility is prioritized, while maintaining appropriate ignition timing during earlier phases for optimal torque buildup. This dynamic adjustment allows the system to achieve both acoustic enhancement and fast shifting.
3Difficulty of detecting and measuring
If one or more cylinders are blanked during the trailing phase, then sporty sound characteristics are enhanced, but the torque reserve required increases
Solution Approach 1:
The patent applies partial action by blanking only one or several cylinders during the trailing phase (fourth phase) rather than all cylinders. This partial blanking generates the desired sporty sound characteristics and exhaust explosions while requiring less torque reserve compared to complete cylinder blanking, thereby resolving the contradiction between acoustic enhancement and energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively reduces abrupt downshifting, enhances driving comfort and stability by providing an acoustically clear, sporty sound, and allows for differentiated sound profiles based on driving programs or vehicle classes, improving the overall driving experience.
Implementation Method 1
By this strong displacement of the ignition angle, that is, the ignition time in the retarded direction, an acoustically clearly perceivable sound, in particular a very sporty sound, is generated by the engine.
Data Source
AI summary
In a method for controlling shifting in a motor vehicle having an internal combustion engine and an automatic transmission, intermediate gas is automatically applied for reducing and/or compensating for an abrupt shift when downshifting. In a first phase, wherein the transmission is in the hydraulic down time thereof, the actual torque provided by the engine is slowly increased, until a torque required by the transmission is achieved. Subsequently, in a second phase, wherein the actual torque of the engine is less than the target torque, a throttle valve is opened further. In a subsequent third phase, in which the actual torque of the engine has achieved the target torque required for synchronization, a late ignition angle is set.