Cruise Control Downshift for Gradient Speed Management
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Solution Overview
Problem
Existing vehicle cruise control systems face challenges in maintaining a predetermined speed on down gradients, as they often rely on complex and expensive automatic braking, which can be surprising and unintuitive for drivers, and may lead to misunderstandings about vehicle faults.
Innovation Solution
A cruise control system that allows drivers to reduce cruise speed through repeated or prolonged inputs, triggering a downshift in the vehicle transmission for additional engine braking, which is only activated when the system recognizes increasing speed on a down gradient, providing a more intuitive and intelligent speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If automatic braking is used to maintain vehicle speed on down gradients, then speed control is effective, but system complexity and cost increase significantly
Solution Approach 1:
The invention extracts the speed control function from the complex automatic braking system and implements it through a simpler transmission downshift mechanism. When the driver activates the speed reduction input, the system downshifts the transmission to provide engine braking, thereby maintaining cruise speed without requiring complex braking system activation.
Solution Approach 2:
The invention uses the existing transmission system, which is already present in the vehicle, to provide speed control on down gradients. Rather than adding a dedicated braking system for this specific function, the patent repurposes the transmission's downshift capability, leveraging an existing component for an additional control function.
2Reliability
If downshift is activated without driver anticipation, then speed control is achieved, but driver confusion and perceived vehicle faults increase
Solution Approach 1:
The system performs preliminary detection of driver intent through repeated or prolonged activation of the speed reduction input before executing the downshift. This preliminary action allows the driver to anticipate the downshift, understanding that their input will trigger a transmission change rather than an unexpected braking event.
Solution Approach 2:
The system provides feedback to the driver through the transmission system itself - the downshift is executed in response to the driver's repeated speed reduction inputs, creating a clear cause-and-effect relationship that helps the driver understand vehicle behavior and maintain control awareness.
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
This solution allows for intuitive and intelligent speed control on down gradients without surprising the driver, maintaining set speeds effectively while avoiding unnecessary complex braking systems, and can be selectively enabled or disabled based on road conditions.
Implementation Method 1
Downshifting of a vehicle transmission results in additional engine braking
Data Source
AI summary
A cruise control system of a motor vehicle includes additional functionality to address increasing vehicle speed on a down gradient. A downshift is commanded upon detection of repeated or prolonged activation of a speed-down control, the additional engine braking reducing vehicle speed to cruise speed in a manner which is within driver expectation.