EV Stall Simulation Control With Brake Hold Assist
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Solution Overview
Problem
Existing control systems for electric vehicles struggle to simulate engine stall behaviors of conventional vehicles without causing undesirable roll-back situations, affecting driving pleasure.
Innovation Solution
A control system for electric vehicles that includes an accelerator, shifting device, virtual torque changing device, and brake device, with a controller that simulates engine stall by stopping the rotary machine and applying brake torque, and executes hold assist control to prevent roll-back.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the output torque of the motor is reduced to zero to simulate engine stall, then the behavior of conventional vehicle engine stall is simulated, but roll-back occurs when simulating engine stall on an upslope
Solution Approach 1:
The patent introduces a brake device as an intermediary element between the motor and the wheel to prevent roll-back during engine stall simulation. The brake device applies brake torque to the wheel independently of the motor torque control, thereby mediating the conflict between simulating engine stall (zero torque) and preventing roll-back (requiring holding force). This allows the system to maintain the simulation fidelity while eliminating the harmful roll-back effect.
2Object-affected harmful factors
If the engine stall simulation is inhibited to prevent roll-back, then roll-back is prevented, but driving pleasure is reduced
Solution Approach 1:
The patent segments the control functions into two independent parts: motor torque control for engine stall simulation and brake torque control for roll-back prevention. The controller can independently manage these two functions, allowing engine stall simulation to be executed fully (reducing motor torque to zero) while simultaneously applying brake torque through the brake device. This segmentation enables both simulation fidelity and safety without compromising driving pleasure.
3Object-affected harmful factors
If the brake torque is applied to prevent roll-back during engine stall simulation, then roll-back is prevented, but the authenticity of engine stall simulation is compromised
Solution Approach 1:
The brake device serves as an intermediary that does not interfere with the motor torque control mechanism. By applying brake torque directly to the wheel rather than through the motor, the system maintains authentic engine stall simulation (zero motor torque) while preventing roll-back. The brake device mediates between the simulation requirements and safety requirements without compromising the authenticity of the engine stall behavior.
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
Prevents roll-back during engine stall simulation, allowing detailed simulation of conventional vehicle behaviors while maintaining driving pleasure.
Implementation Method 1
execute a hold assist control to apply the brake torque to the wheel by the brake device
Data Source
AI summary
A control system for an electric vehicle configured to simulate an engine stall which might occur in conventional vehicles while preventing the simulation of the engine stall in an unfavorable situation. A controller of the control system is configured to: execute an engine stall control to simulate a behavior of the conventional vehicle in a situation where an engine stall occurs by stopping a motor, when a virtual engine speed calculated by a virtual engine speed calculator falls below a predetermined speed; and execute a hold assist control to apply a brake torque to the wheel by the brake device upon execution of the engine stall control.