Hill Start Brake Release via Torque-Speed Map Zones

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Solution Overview

Problem

Existing hill start assistance methods for motor vehicles, particularly those with low-torque engines, face challenges in ensuring engine torque sufficiency for take-off on inclines, leading to potential stalling and requiring complex sensor systems that increase costs and calculation times.

Innovation Solution

A method that maps engine torque versus engine speed to define authorized and prohibited zones for hill starts, allowing automatic brake release only when the engine operating point is within the authorized zone, using a single inclination sensor to minimize sensor requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple sensors are implemented to ensure sufficient engine torque for hill start, then the reliability of hill start assistance is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvehill start assistance reliabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates unnecessary sensors from the hill start assistance system. By analyzing the actual parameters needed for torque sufficiency assessment, the invention determines that only one sensor is required, removing redundant sensing elements while maintaining reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The single sensor implemented in the patent serves multiple functions: it measures inclination angle, provides data for torque calculation, and enables the electronic control unit to determine operating zone. This multi-functional approach replaces what would traditionally require multiple specialized sensors

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

2Reliability

If multiple sensors and complex electronic management are used to prevent engine stalling, then the reliability of hill start assistance is improved, but the calculation time increases

Engineering Contradiction:
Improveengine stalling preventionVSAvoidcalculation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-defining the authorized and prohibited zones in the map before operation. The electronic control unit simply needs to compare current operating parameters against this pre-established map, avoiding complex real-time calculations and reducing decision time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention transforms the control problem from continuous complex calculation to discrete zone comparison. By changing the representation of safe operating conditions into a map with defined zones, the system achieves faster decision-making through simple parameter matching rather than complex computational analysis

Inventive Principle:
Principle #35Parameter changes

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 simplifies the system, reduces costs, and effectively prevents engine stalling by ensuring sufficient torque for take-off without needing to measure the vehicle's mass or complex electronic management, while maintaining assistance for various engine types and slopes.

Implementation Method 1

measure the inclination of the vehicle

Methodology Applied
Scientific EffectInclination sensing: Accelerometer

Data Source

PatentEP2170682B1Method for assisting with hill starts
Publication Date: 2012.05.16 RENAULT SA
  • EP2170682B1 patent drawingFigure 1
  • EP2170682B1 patent drawingFigure 2

AI summary

The invention relates to a method for assisting a motor vehicle with a hill start, the motor vehicle having previously been held stationary when parked by a brake, the method involving the steps that consist in:- measuring the inclination of the vehicle, and - automatically releasing the brake. According to the invention, the method essentially further comprises the steps involving: previously establishing a map between the engine torque and the engine speed, - defining, within the map, an authorized zone and a forbidden zone, - providing a vehicle engine speed value, - providing a vehicle engine torque value, deducing from these the coordinates of the engine operating point within the map, and - releasing the brake automatically only if the coordinates of the operating point lie within the authorized zone of the map.