Neutral Idle Control via Stop Type Detection
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Solution Overview
Problem
Existing neutral-idle systems in motor vehicles often cause drivability issues due to delayed acceleration when engaging neutral idle at stop signs, providing little fuel savings and an unsatisfactory driving experience, while traditional systems without navigation or adaptive cruise control rely on delay timers, which are inefficient.
Innovation Solution
A vehicle controller system that uses navigation and adaptive cruise control inputs to determine if the vehicle is stopped at a traffic light or stop sign, thereby deciding whether to shift the transmission into neutral idle, eliminating the need for delay timers and maintaining the transmission in drive at stop signs to prevent drivability issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If neutral idle is engaged at all stops, then fuel economy is improved, but acceleration performance deteriorates due to delayed response at stop signs
Solution Approach 1:
The system dynamically adjusts transmission state based on real-time driving conditions. The controller monitors stop type (traffic light vs. stop sign) and vehicle context, switching between neutral idle and drive state accordingly. This dynamic adaptation allows the system to optimize fuel economy at traffic lights while maintaining acceleration readiness at stop signs, resolving the contradiction between fuel efficiency and acceleration performance.
Solution Approach 2:
The system changes the operational parameter of transmission state (engaged vs. neutral) based on detected conditions. By using navigation data, stop detection algorithms, and stop type classification, the controller changes the transmission parameter selectively - engaging neutral idle only when conditions indicate a traffic light stop with sufficient duration, thereby improving fuel economy without sacrificing acceleration response when needed.
2Speed
If delay timer is used to inhibit neutral idle, then acceleration response is maintained, but fuel economy is compromised due to unnecessary engagement at traffic lights
Solution Approach 1:
The system implements feedback through stop type detection and context analysis. Rather than using a simple delay timer, the controller continuously monitors navigation data, stop duration, stop type classification, and vehicle state to make informed decisions about neutral idle engagement. This feedback mechanism ensures neutral idle is engaged only when beneficial (at traffic lights with sufficient wait time) while maintaining drive state at stop signs, optimizing both acceleration response and fuel economy.
Solution Approach 2:
The system performs preliminary analysis of stop characteristics before deciding on neutral idle engagement. By detecting stop type, estimating duration, and analyzing context in advance, the controller determines the appropriate transmission state before the stop begins or early in the stop, rather than relying on post-stop delay timers. This preliminary action allows optimal fuel economy at traffic lights while maintaining readiness at stop signs.
3Device complexity
If neutral idle is engaged without stop type detection, then system complexity is reduced, but drivability deteriorates due to inappropriate engagement at stop signs
Solution Approach 1:
The system introduces an intermediary layer of stop detection and classification logic that bridges the simple neutral idle control and the complex driving conditions. Rather than directly engaging neutral idle based on basic conditions, the controller uses navigation data, stop type detection, and context analysis as intermediaries to make intelligent decisions. This intermediary layer adds minimal complexity while dramatically improving drivability by preventing inappropriate neutral idle engagement at stop signs.
Data Source
AI summary
A vehicle includes an engine and driven wheels each having an associated friction brake. A brake pedal is operable to engage the friction brakes. The vehicle includes a transmission having an input shaft driveably connected to the engine, an output element driveably connected to the driven wheels, and a gear mechanism adapted to establish at least one torque flow path between the input shaft and the output element. The transmission further includes a shift element that interrupts the torque flow path when disengaged. A gear selector is disposed in the passenger cabin and includes at least one forward-drive position, a reverse position, and a neutral position. At least one vehicle controller is configured to, in response to the gear selector being in the forward-drive position, a speed of the vehicle being zero, the vehicle being within a first predefined distance of a stoplight, and the brake pedal being depressed, disengage the shift element to put the transmission in neutral idle.