Vehicle Deceleration via Electrical Machine Torque Control
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Solution Overview
Problem
Existing methods for maneuvering heavy vehicles at low speeds, such as those used in loading and unloading operations, face challenges with clutch engagement and disengagement, leading to friction losses, sudden torque changes, and increased risk of accidental movements due to clutch slip, which complicates precise control and safety.
Innovation Solution
A method utilizing an electrical machine to apply brake torque when the driver reduces or releases the accelerator pedal, allowing the vehicle to decelerate and remain stationary without the need for clutch engagement, thereby eliminating clutch-related issues and simplifying control through the use of the accelerator pedal for both propulsion and deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If clutch engagement and disengagement is used for low-speed maneuvering, then the vehicle can be controlled to move forward and backward, but friction losses increase and sudden torque changes occur leading to accidental movements
Solution Approach 1:
The invention extracts the clutch component from the power transmission path during low-speed maneuvering. By using the electrical machine to directly apply brake torque to the drive wheels, the clutch is bypassed entirely, eliminating friction losses and sudden torque changes associated with clutch engagement and disengagement.
Solution Approach 2:
The invention replaces the mechanical clutch-based torque control system with an electrical machine-based brake torque system. The electrical machine can apply torque smoothly and precisely without the mechanical friction and sudden engagement characteristics of a clutch, thereby reducing energy loss while maintaining maneuverability.
2Speed
If clutch slip is used to enable low-speed movement, then the vehicle can move at very low speeds, but the risk of accidental movements increases due to sudden clutch engagement
Solution Approach 1:
The invention replaces the mechanical clutch system with an electrical machine control system. The electrical machine can modulate torque output smoothly and predictably, eliminating the sudden engagement and slip characteristics of mechanical clutches that lead to accidental movements, while maintaining the ability to move at very low speeds.
Solution Approach 2:
The invention implements feedback control through the vehicle's control system that continuously monitors wheel speed and torque application. This allows the electrical machine to adjust brake torque in real-time, preventing sudden movements and ensuring safe, controlled low-speed maneuvering without the unpredictable behavior of clutch slip.
3Speed
If conventional brake system is used for deceleration, then the vehicle can be stopped, but additional brake pedal operation is required increasing driver workload
Solution Approach 1:
The invention makes the electrical machine multi-functional by using it for both propulsion and deceleration. The same electrical machine that provides torque for acceleration can also apply brake torque for deceleration, eliminating the need for a separate brake system operation and reducing driver workload to simple accelerator pedal release.
Solution Approach 2:
The invention merges the propulsion and braking functions into a single electrical machine system. By combining these functions, the system eliminates the need for separate brake pedal operation, as releasing the accelerator pedal automatically activates the electrical machine's brake torque capability, simplifying driver operation.
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 approach provides smoother and more precise control during low-speed maneuvers, reducing the risk of sudden movements and allowing the vehicle to be kept stationary without the need for active brake pedal use, enhancing safety and reducing clutch-related complications.
Implementation Method 1
applying a first brake torque by means of said electrical machine, by means of said first brake torque decelerate said vehicle
Implementation Method 2
when said vehicle has been decelerated to said stationary state, continue applying a torque by means of said electrical machine to keep said vehicle in said stationary state
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present invention relates to a method for decelerating a vehicle (100) comprising an electrical machine (110) being arranged to provide a controllable torque to at least one drive wheel (113, 114), said vehicle (100) including driver controllable means for actively requesting a torque for propelling the vehicle (100). The method includes, when a driver request for a propelling torque is reduced at least to a first extent: - applying a first brake torque ( T brake ) by means of said electrical machine, - by means of said first brake torque ( T brake ), decelerate said vehicle (100) to a stationary state, and - by means of said electrical machine (110), when said vehicle (100) has been decelerated to said stationary state, continue applying a torque ( T hold ) by means of said electrical machine (110) to keep said vehicle (100) in said stationary state.