Rolling Engine Start-Stop NVH Reduction via Dynamic Speed Target
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional engine start-stop systems experience a stop delay that results in noticeable noise/vibration/harshness (NVH) or 'jerk' when shutting down the engine, which is unpleasant for the driver.
Innovation Solution
A rolling engine start-stop (RESS) system that dynamically determines a target vehicle speed for engine shutdown based on driver input, vehicle speed, and steering angle, selectively stopping the engine at this speed to minimize NVH, and schedules actuators like fuel, spark, throttle, and transmission to account for individual delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If engine stop delay is implemented in conventional engine start-stop systems, then fuel economy is improved, but noise/vibration/harshness (NVH) increases due to noticeable jerk during shutdown
Solution Approach 1:
The system performs preliminary actions by pre-positioning actuators (fuel injector, throttle valve, spark plug, transmission) before engine shutdown. This includes cutting fuel supply in advance, closing throttle valve beforehand, disabling spark ignition prior to shutdown, and pre-selecting transmission gear to match final vehicle speed, thereby eliminating NVH caused by sudden actuator changes during shutdown
Solution Approach 2:
The system dynamically determines a target vehicle speed for engine shutdown based on real-time vehicle operating conditions, including vehicle speed, acceleration rate, and driver behavior patterns. This dynamic adjustment allows the engine to shutdown at optimal speeds that minimize NVH while maintaining fuel economy benefits
2Loss of energy
If engine shutdown is implemented at any vehicle speed, then fuel economy is improved, but unnecessary start-stop events occur during parking maneuvers causing obstruction
Solution Approach 1:
The system continuously monitors steering wheel angle as feedback to detect parking maneuvers. When the steering wheel angle exceeds a predetermined threshold, indicating a parking maneuver is in progress, the system inhibits engine shutdown to prevent temporary obstruction by obstacles, thereby adapting engine start-stop behavior to driving context
Data Source
AI summary
Rolling engine start-stop (RESS) system and methods for a vehicle include a set of sensors configured to measure a set of operating parameters of the vehicle comprising at least (i) driver input via brake pedal of the vehicle, (ii) vehicle speed, and (iii) a steering angle of the vehicle and a controller configured to, based on the set of operating parameters, determine a target vehicle speed for stopping an engine of the vehicle, and based on the steering angle of the vehicle, selectively stopping the engine of the vehicle when the vehicle speed falls to the determined target vehicle speed, wherein stopping the engine of the vehicle at the determined target vehicle speed decreases noise/vibration/harshness (NVH) caused by stopping the engine.