Virtual Gear Control for EV Torque and Deceleration Tuning

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Solution Overview

Problem

Electrically driven road vehicles lack the engaging driving experience and driver involvement due to the reduced need for gear shifting, as electric powertrains can provide torque and speed without mechanical constraints, leading to diminished driving pleasure, especially in high-performance vehicles.

Innovation Solution

A control method for electrically driven road vehicles that introduces a virtual gear system allowing drivers to select from multiple acceleration and deceleration profiles, enabling customizable torque delivery and deceleration through an interface system, independent of traditional gear shifting, using an electronic control unit to manage torque and suspension actively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If electric powertrain systems are used to eliminate mechanical transmission constraints, then vehicle performance and acceleration capability are improved, but driver involvement and driving pleasure are reduced

Engineering Contradiction:
Improveacceleration capabilityVSAvoiddriver involvement
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The system dynamically adjusts torque delivery characteristics through software-controlled virtual gear shifts, allowing the electric powertrain to adapt its behavior between different driving modes (e.g., acceleration-oriented, efficiency-oriented, driver-engagement-oriented) without mechanical complexity. This resolves the contradiction by making the system flexible enough to provide both high performance and driver involvement as needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of torque delivery characteristics by implementing virtual gear ratios that modify how torque is delivered to the wheels. By adjusting these virtual gear parameters software-based, the system maintains electric powertrain performance while creating engagement points for the driver through simulated gear-shifting behavior, thus resolving the contradiction between performance and driver involvement.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If traditional mechanical gear-shifting systems are used, then driver engagement and driving pleasure are improved, but mechanical complexity and transmission constraints are increased

Engineering Contradiction:
Improvedriver engagementVSAvoidmechanical transmission complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention replaces the mechanical gear-shifting system with a software-based virtual gear system. The electronic control unit modifies torque delivery characteristics to simulate different gear ratios without any mechanical transmission components, thereby maintaining driver engagement through virtual gear-shifting feedback while eliminating mechanical complexity and constraints.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system creates a virtual copy of traditional gear-shifting behavior through software control of torque delivery. By replicating the engagement characteristics of mechanical gear shifts through electronic torque modulation, the invention provides driver engagement without requiring actual mechanical gears, thus resolving the contradiction between driver engagement and mechanical complexity.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If virtual gear system with multiple acceleration profiles is implemented, then driving customization and engagement are improved, but control system complexity is increased

Engineering Contradiction:
Improvedriving customizationVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The electronic control unit is designed to perform multiple functions: it manages the electric powertrain, implements virtual gear shifts, adjusts torque delivery characteristics, and provides driver engagement feedback. By consolidating these functions into a single software-based control system rather than requiring separate hardware components for each function, the invention achieves high adaptability while minimizing control system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4257441A1Control method for an electrically driven road vehicle driven by a driver, and relative road vehicle
Publication Date: 2023.10.11 FERRARI SPA
  • EP4257441A1 patent drawingFigure 1
  • EP4257441A1 patent drawingFigure 2
  • EP4257441A1 patent drawingFigure 3

AI summary

A control method for an electrically driven road vehicle (1) comprising the steps of: providing an electric powertrain system (4); determining a plurality of first virtual gears (8) for a boost configuration (PC) and/or a plurality of second virtual gears (9) for a release configuration (RC); detecting, following actuation of an interface system (7) by the driver (DR), while driving, a first selection (S') for one of the first virtual gears (8) and/or a second selection (S") for one of the second virtual gears (9); and delivering, in the boost configuration (PC), a drive torque to the at least two wheels (2) as a function of the first selection (S'); or delivering, in the release configuration (RC), an anti-motive torque to the at least two wheels (2) according to the second selection (S").