Brake Control System Stationary Mode Switching

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Solution Overview

Problem

Conventional brake control systems generate excessive braking force when stationary, leading to wasteful electric-power consumption and heat generation, and can cause vehicles to accelerate unintentionally when starting from a stop, especially in heavy traffic.

Innovation Solution

A brake control apparatus that switches between normal and stationary-vehicle control modes based on the vehicle's state, limiting braking force to a predetermined level when stationary and adjusting accordingly to match the driver's input, thereby reducing energy consumption and ensuring smooth starts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a braking force larger than necessary is generated while the vehicle is stationary, then the vehicle remains reliably stationary, but electric-power consumption and heat generation increase wastefully

Engineering Contradiction:
Improvevehicle stationary stabilityVSAvoidelectric-power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The brake control apparatus dynamically adjusts the braking force based on vehicle motion state. When the vehicle is stationary, the braking force is reduced to a minimum level sufficient to maintain stationarity rather than maintaining a constant high braking force, thereby reducing energy consumption while ensuring the vehicle remains stationary when needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the braking force parameter according to the vehicle's motion state. By detecting whether the vehicle is moving or stationary, the control apparatus adjusts the braking force magnitude appropriately - maintaining sufficient braking force for stationary stability while minimizing energy consumption during stationary periods

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a large braking force is generated while stationary, then the vehicle remains stationary reliably, but heat generation increases wastefully

Engineering Contradiction:
Improvevehicle stationary stabilityVSAvoidheat generation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The brake control apparatus dynamically adjusts the braking force based on vehicle motion state. When the vehicle is stationary, the braking force is reduced to a minimum level sufficient to maintain stationarity rather than maintaining a constant high braking force, thereby reducing heat generation while ensuring the vehicle remains stationary when needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the braking force parameter according to the vehicle's motion state. By detecting whether the vehicle is moving or stationary, the control apparatus adjusts the braking force magnitude appropriately - maintaining sufficient braking force for stationary stability while minimizing heat generation during stationary periods

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the braking force is reduced slowly to zero, then energy consumption is reduced, but the residual braking force prevents the vehicle from starting smoothly

Engineering Contradiction:
Improveelectric-power consumptionVSAvoidvehicle starting smoothness
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The control apparatus preliminarily reduces the braking force to a minimal level sufficient for stationary stability before the vehicle needs to start moving. This preliminary action ensures that when the driver intends to start the vehicle, the braking force is already minimized, allowing smooth acceleration without residual braking resistance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the braking force based on detected vehicle motion intent. When starting is detected or anticipated, the braking force is rapidly reduced to minimal levels, enabling smooth vehicle startup while maintaining energy efficiency during stationary periods

Inventive Principle:
Principle #15Dynamics

4Use of energy by moving object

If the braking force remains at a residual level, then energy consumption is reduced, but the vehicle may accelerate unintentionally when the driver depresses the brake pedal lightly

Engineering Contradiction:
Improveelectric-power consumptionVSAvoidbraking control accuracy
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The control apparatus preliminarily reduces the braking force to a minimal level before the driver's braking input is applied. This preliminary reduction ensures that when the driver depresses the brake pedal, the actual braking force is proportional to the driver's input without being offset by residual braking force, maintaining braking control accuracy while minimizing energy consumption

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the braking force parameter to a minimal level when stationary, ensuring that driver braking inputs are accurately reflected in the actual braking force without interference from residual braking. This parameter adjustment maintains reliable braking control while reducing energy consumption during stationary periods

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2163445B1Brake control system
Publication Date: 2016.12.21 HITACHI AUTOMOTIVE SYST LTD
  • EP2163445B1 patent drawingFigure 1
  • EP2163445B1 patent drawingFigure 2
  • EP2163445B1 patent drawingFigure 3

AI summary

Provided is a brake control apparatus 1 for a vehicle which detects an amount of brake-pedal 2, 100 operation by means of an electric signal output from a steering angle sensor 8, and then calculates a braking force demanded by a driver from the electric signal, and thereby generates the demanded braking force. A control mode for a braking force is switched from a normal control mode to a stationary-vehicle control mode, if a determination that the vehicle is in a stationary state is followed by another determination that an electric signal corresponding to an actual braking force exceeds a command value for a stationary-vehicle braking force while the vehicle is in the stationary state. The control mode for a braking force is switched from the stationary-vehicle control mode to the normal control mode, if it is determined that the demanded braking force becomes smaller than the command value for the stationary-vehicle braking force. In addition, in the stationary-vehicle control mode, a braking force generated by a means for braking is equal to the command value for the stationary-vehicle braking force, whereas, in the normal control mode, the braking force generated by the means for braking is equal to the braking force demanded by the driver.