Hybrid Vehicle Speed Control System for Adaptive Cruise
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Solution Overview
Problem
Adaptive cruise control systems in hybrid electric vehicles struggle to maintain efficient operation in EV mode, particularly when following vehicles accelerate rapidly or in varying traffic conditions, leading to increased fuel consumption and decreased driver satisfaction due to limited acceleration capabilities.
Innovation Solution
A speed control system that allows drivers to set a target vehicle speed, operating in two modes: a first mode that limits the vehicle to EV mode with restricted acceleration or torque, and a second mode that enables engine assistance for higher acceleration, automatically switching between modes based on conditions such as traffic density, driver demands, and terrain, ensuring the vehicle maintains a prescribed distance while optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the vehicle operates in EV mode with limited acceleration capability, then fuel consumption is reduced, but the vehicle cannot maintain prescribed distance when followed vehicle accelerates rapidly
Solution Approach 1:
The system dynamically switches between EV mode and engine assistance mode based on real-time traffic conditions and acceleration requirements. When the followed vehicle accelerates rapidly, the system transitions from EV mode to engine mode to maintain the prescribed following distance, while returning to EV mode under normal conditions to minimize fuel consumption.
Solution Approach 2:
The control system changes operational parameters by adjusting the available acceleration rate and torque based on the selected mode. In EV mode, the maximum acceleration is limited to electric-only capabilities, while in engine mode, the system allows higher acceleration rates by engaging the internal combustion engine, thus adapting to different traffic scenarios.
2Use of energy by moving object
If the system limits acceleration to EV mode capabilities, then energy efficiency is improved, but driver satisfaction decreases due to inadequate acceleration response
Solution Approach 1:
The system provides dynamic acceleration response by switching between EV mode and engine mode based on driver demands and traffic conditions. When rapid acceleration is required for driver satisfaction, the system engages the engine while maintaining an interface that presents unified control to the driver, thus preserving ease of operation across different modes.
Solution Approach 2:
The vehicle powertrain is designed with multi-functionality, capable of operating in EV mode for energy efficiency and engine mode for high-performance acceleration. The control system seamlessly manages both modes, allowing the same vehicle to serve different operational requirements without requiring separate systems.
3Speed
If the vehicle switches between EV mode and engine mode, then acceleration capability is improved, but system complexity increases
Solution Approach 1:
The control system merges the management of EV mode and engine mode into a unified adaptive cruise control interface. The system integrates the hybrid powertrain control with ACC functionality, allowing seamless transitions between modes through a single control architecture that manages both electric and combustion power sources together.
4Speed
If the system allows engine assistance in all conditions, then acceleration performance is maintained, but fuel consumption increases
Solution Approach 1:
The system changes the operational state of the powertrain by switching between EV mode and engine mode based on calculated acceleration requirements. The control system monitors traffic conditions, followed vehicle acceleration, and driver demands to determine when engine assistance is necessary, thereby optimizing the balance between acceleration performance and fuel consumption.
Data Source
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AI summary
The invention provides a speed control system and method for a hybrid electric vehicle, the vehicle having an engine (121), an electric machine (123) and a mode switch (169), to allow switching between a first speed control mode (EV) and a second speed control mode (HEV). When the control system is in the first mode and at least one of a prescribed one or more conditions is met, e.g. a rate of acceleration demanded by the driver or a difference between a target vehicle speed and a current vehicle speed exceeds a respective prescribed threshold value, the system is operable to not limit operation of the vehicle to the EV mode.