Hill Start Aid Torque Compensation via Pitching Detection

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Solution Overview

Problem

Existing hill start aid systems for vehicles are sensitive to body pitching, leading to late take-off due to inaccurate torque estimation, especially when passengers or vehicle movements affect the slope sensor data.

Innovation Solution

A method that generates an instruction to release the automatic parking brake based on specific vehicle conditions, including minimum speed, gear engagement, accelerator pedal position, and torque threshold, which is calculated as a function of the slope characteristic to ensure the vehicle is ready to take off, thereby compensating for body pitching effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the brake is released when torque compensates for slope effect, then the vehicle can start on a slope, but the take-off is delayed due to body pitching causing inaccurate torque estimation

Engineering Contradiction:

Improvehill start assistance reliabilityVSAvoidtake-off delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary detection of body pitching motion before the vehicle starts moving. By detecting the pitching acceleration of the vehicle body in advance and using this information to compensate for torque estimation errors, the system prepares the brake release timing ahead of time, avoiding delayed take-off while maintaining reliable hill start assistance.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If a low-pass filter is introduced to filter sensor noise, then high-frequency noise is reduced, but the torque estimation remains imprecise when body pitching occurs

Engineering Contradiction:

Improvesensor signal precisionVSAvoidtorque estimation accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system introduces body pitching detection as an intermediary measurement to indirectly assess the impact of vehicle body motion on torque estimation. By detecting the pitching acceleration of the vehicle body and using it to compensate for the torque estimation error caused by body pitching, the system achieves accurate torque measurement even during vehicle body motion without relying solely on filtering the slope sensor signal.

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

The solution ensures the vehicle takes off smoothly by accurately determining the torque required to overcome the slope effect, reducing the impact of body pitching and enhancing the reliability of hill start maneuvers.

Implementation Method 1

a slope sensor, means for determining the speed of the vehicle

Methodology Applied

Scientific EffectGravitation: Gravitation

Implementation Method 2

an Automatic Parking Brake

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP2162336B1Method providing assistance with hill starts

Publication Date: 2017.03.29 RENAULT SA

AI summary

The invention relates to a method providing assistance with hill starts to a vehicle comprising a power plant connected to the driven wheels by means of a clutch and an automatic parking brake, characterized in that it involves a step that consists in generating an instruction to store in memory the characteristic of the gradient (? gradient) which corresponds to a state in which it is reckoned that the user and the vehicle are ready to pull away, on the basis of conditions that given physical parameters of the vehicle must satisfy.