Hybrid Vehicle Drive Control for Start-Stop Frequency Reduction

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Solution Overview

Problem

Traditional start-stop systems in hybrid electric vehicles lead to reduced engine service life due to frequent start-stops, increased fuel consumption, and poor ride comfort, while also being costly and limited in functionality.

Innovation Solution

A drive control method and device that determines whether the vehicle is within a taxiing start-stop interval based on gear position and battery charge level, allowing for a small load stop or stall function, reducing starter frequency and converting kinetic energy back into battery power, thus extending component life and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional start-stop systems are used to reduce fuel waste and air pollution, then fuel consumption and emissions are reduced, but the engine service life is shortened due to frequent start-stops

Engineering Contradiction:
Improvefuel consumptionVSAvoidengine service life
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system introduces multiple parameters (vehicle speed, accelerator position, brake status, gear position) to dynamically determine when start-stop control should be applied. By changing the control parameters from simple on/off to multi-condition based decisions, the system reduces unnecessary frequent start-stops while maintaining fuel efficiency benefits during appropriate conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The start-stop control is made dynamic rather than static. The system continuously monitors vehicle conditions and adjusts the start-stop behavior in real-time, enabling the engine to remain running when conditions indicate frequent start-stops would be harmful, while still implementing start-stop when conditions are favorable, thus balancing fuel efficiency and engine durability.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If automatic start-stop system is implemented to improve fuel economy, then fuel consumption is reduced, but system complexity and cost increase due to multiple conditions and components

Engineering Contradiction:
Improvefuel consumptionVSAvoidsystem complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The control system is designed to serve multiple functions: it manages start-stop control, monitors vehicle conditions, evaluates multiple parameters simultaneously, and coordinates with existing vehicle systems (engine control, transmission control). This multi-functionality reduces the need for separate dedicated systems while achieving fuel efficiency goals.

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

Solution Approach 2:

The system leverages existing vehicle sensors and control units that are already present in modern vehicles (accelerator position sensors, brake status sensors, gear position sensors). By utilizing these existing components for the start-stop control logic, the system avoids adding significant new hardware complexity while achieving intelligent fuel management.

Inventive Principle:
Principle #25Self-service

3Loss of energy

If frequent start-stop control is applied to reduce fuel waste, then fuel economy is improved, but ride comfort deteriorates due to vibration and noise

Engineering Contradiction:
Improvefuel economyVSAvoidride comfort
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The system uses multiple parameters (vehicle speed threshold, accelerator position, brake status, gear position) to identify conditions where start-stop should be avoided. By monitoring these parameters, the system prevents start-stops during conditions that would cause frequent interruptions and discomfort, such as when the vehicle is already moving or when rapid acceleration is needed.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system proactively prevents start-stop conditions from occurring by evaluating multiple parameters in advance. When conditions suggest that a start-stop would lead to frequent cycling and discomfort (such as when vehicle speed indicates movement or when accelerator position suggests upcoming acceleration), the system preemptively maintains engine running status, thus avoiding the harmful effects before they occur.

Inventive Principle:
Principle #9Preliminary anti-action

4Object-generated harmful factors

If start-stop system is used to reduce emissions, then air pollution is reduced, but system reliability decreases due to limited operating conditions

Engineering Contradiction:
Improveair pollutionVSAvoidsystem reliability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The system dynamically adapts to various vehicle operating conditions by continuously monitoring multiple parameters. Rather than applying a fixed start-stop rule, the system adjusts its behavior based on real-time conditions such as vehicle speed, accelerator position, and gear state, making it reliable across diverse driving scenarios while still achieving emission reduction benefits.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback from multiple vehicle sensors to continuously evaluate whether start-stop conditions are appropriate. By monitoring accelerator position, brake status, gear position, and vehicle speed, the system receives feedback about current operating conditions and adjusts start-stop behavior accordingly, ensuring reliable operation across different driving situations while maintaining emission reduction effectiveness.

Inventive Principle:
Principle #23Feedback

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 increases driving distance, reduces fuel consumption and emissions, and enhances ride comfort by minimizing engine start-stops, while ensuring component longevity and energy recovery.

Implementation Method 1

In addition, if the vehicle has an accelerator-releasing energy feedback function, wasted kinetic energy may be converted to electric energy by a motor through the energy feedback and stored in a power battery

Methodology Applied
Scientific EffectEnergy feedback: Electromagnetic Induction

Data Source

PatentEP3274228B1Hybrid electric vehicle, drive control method and device of the same
Publication Date: 2019.08.21 BYD CO LTD
  • EP3274228B1 patent drawingFigure 1
  • EP3274228B1 patent drawingFigure 2~3
  • EP3274228B1 patent drawingFigure 4

AI summary

A hybrid electric vehicle and a drive control method and device thereof are provided. The method includes: obtaining a current gear position of the vehicle, a current electric charge level of a power battery and a slope of a road on which the vehicle is driving; determining whether the vehicle is within a taxiing start-stop interval according to the current gear position, the current electric charge level, and the slope; if the vehicle is within the taxiing start-stop interval, further obtaining a current speed of the vehicle; if the current speed is greater than or equal to a first speed threshold, and less than a second speed threshold, causing the vehicle to enter a small load stop function; and if the current speed is greater than or equal to the second speed threshold, and less than a third speed threshold, causing the vehicle to enter a small load stall function.