Vehicle Charge Controller for Battery SOC Maintenance

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Solution Overview

Problem

The existing charge control techniques for vehicles can cause engine restart due to a decrease in State of Charge (SOC) of the battery during idle reduction control, leading to increased fuel consumption, as they fail to effectively manage high current consumption from auxiliary machinery like indicators and power steering.

Innovation Solution

A charge control device that detects changes in auxiliary machinery load and controls the generator voltage based on the load condition, excluding instantaneous high current changes as noise and smoothing the current values to prevent SOC depletion, thereby optimizing power generation and reducing engine restarts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the charge controller controls generator voltage based on high current consumption from auxiliary machinery (indicators, power steering, etc.), then the SOC of the battery is maintained, but fuel consumption increases due to excessive power generation

Engineering Contradiction:
ImproveSOC maintenanceVSAvoidfuel consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary classification of current consumption patterns by comparing against threshold values and determining whether high current is caused by auxiliary machinery operations. This preliminary analysis allows the controller to distinguish between legitimate high current needs (power steering, indicators) and normal variations, enabling selective power generation control that maintains SOC only when necessary.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller dynamically changes the generator's output voltage parameter based on the determined current consumption pattern. When high current is determined to be from auxiliary machinery, the controller increases generator voltage to charge the battery; when high current is from other sources or the auxiliary machinery is not operating, the controller reduces or maintains normal voltage levels, thereby optimizing fuel consumption while ensuring SOC maintenance only when required.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the charge controller excludes high current from auxiliary machinery as noise, then fuel consumption is reduced, but SOC may decrease causing engine restart during idle reduction control

Engineering Contradiction:
Improvefuel consumptionVSAvoidSOC level
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The controller changes the detection parameter from simply excluding high current as noise to actively detecting whether high current is caused by specific auxiliary machinery operations using threshold comparison. This parameter change enables the system to identify legitimate high current consumption patterns and respond appropriately by increasing power generation only when auxiliary machinery is operating, thus preventing SOC depletion while avoiding unnecessary fuel consumption from continuous high power generation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the charge controller continuously monitors and responds to instantaneous current changes, then SOC is precisely maintained, but system complexity and response time increase

Engineering Contradiction:
ImproveSOC control precisionVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system changes from monitoring raw instantaneous current values to monitoring a processed parameter: the determination result of whether high current is caused by auxiliary machinery. This parameter transformation simplifies the control logic by converting complex current pattern analysis into a binary decision based on threshold comparison, reducing computational complexity while maintaining effective SOC control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system introduces an intermediary determination step between current detection and power generation control. The load condition detector acts as an intermediary that processes raw current signals, compares them against threshold values, and generates a simplified control signal indicating whether auxiliary machinery is causing high current. This intermediary layer filters out noise and simplifies the control algorithm, reducing system complexity while maintaining control precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 improves fuel efficiency by minimizing engine restarts due to SOC depletion and reduces fuel consumption, as increasing SOC during engine operation is more fuel-efficient than restarting the engine due to low SOC during stop and start periods.

Implementation Method 1

a generator (35) driven with power of the engine (10)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a battery (40) that is chargeable with electric power generated by the generator (35)

Methodology Applied
Scientific EffectElectrical energy storage: Battery (electricity)

Data Source

PatentEP2982850B1Charging control device, vehicle control device, vehicle, charging control method, and vehicle control method
Publication Date: 2019.06.19 TOYOTA JIDOSHA KK
  • EP2982850B1 patent drawingFigure 1
  • EP2982850B1 patent drawingFigure 2
  • EP2982850B1 patent drawingFigure 3

AI summary

A charge control device for a battery is mounted on a vehicle, the vehicle comprises an engine, a generator driven with power of the engine, the battery configured to be chargeable with electric power generated by the generator, and auxiliary machinery operated with electric power of the battery. The charge control device comprises: a load condition detector that is configured to detect a load condition of the auxiliary machinery; and a charge controller that is configured to control charging into the battery, based on the load condition of the auxiliary machinery, wherein in response to detection of a state change from a state in which a magnitude of the load of the auxiliary machinery is smaller than a predetermined threshold value to a state in which a magnitude of the load is larger than the predetermined threshold value, the charge controller controls a generated voltage by the generator based on the magnitude of the load of the auxiliary machinery prior to the state change during a time period until a specified time has elapsed after the detection of the state change, and the charge controller controls a generated voltage by the generator based on a magnitude of the load of the auxiliary machinery detected by the load condition detector during a time period after elapse of the specified time.