Collapsible and contractive antiroll bar _ November 2013

This document is strictly confidential and for PwC use only

Collapsible and Contractive antiroll bar

Automotive application

Inventor: Mr Fausto Garsi

November 2013

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Bushidō Consulting - Overview

Bushidō Consulting is a business development consulting firm and a professional network,

with operational offices in Turin, Modena, and Rome - Italy, Baden Baden - Germany,

Prague - Czech Republic and Detroit - USA.

Established in May 2010, capitalizing on 20 years of international experiences in the

automotive business by its founder Maurizio Agostini and professional Partners across the

whole product lifecycle: Marketing, Business Development, Product and Process

Engineering, Quality Management, Manufacturing, Key Account and Retail Sales, Dealer

Network Development, Product Support.

The Partners acquired such experience and competence working in management positions

within international world-class corporations such as:

Specialized in supporting enterprises of all sizes to create sustainable growth through

successful expansion into international markets.

Helping clients become more competitive and profitable in their business, providing sales

and marketing development expertise and executive management consulting experience.

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This document and the information thereon is the property of Bushidō Consulting and may only be used for the purpose for which it is supplied


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Born in Milan - Italy on September 27th, 1969

Graduated in Mechanical Engineering from the Politecnico of Milan

Involved since 2002 in the racing car field as race car engineer

Currently Technical Director of a Formula 3 Team

Resident in Milan - Italy

Mr Fausto Garsi - Profile



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Project of cooperation

Bushidō Consulting and Mr Fausto Garsi have an agreement for the development of a project

of cooperation.

Mr Fausto Garsi has decided to avail itself of the service offered by Bushidō Consulting, which

foresees a business development support concerning the presentation of an innovative

automotive mechanical device concept by key cars manufacturers and Tier1 suppliers in

Europe, other reference countries can be considered.

The device concept is covered by a relevant Patent and is related to the configuration of a

collapsible and contractive anti roll bar for vehicle applications.

The aim of the project of cooperation is to identify opportunities of design application within the

automotive market, through the definition and execution of a relevant project development plan.

Bushidō Consulting is responsible for the development of initiatives involving car manufacturers

and OEMs interested in the above mentioned device concept and acts as main point of contact

with them.



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Deposit number: MI2011A002097 - Date of Deposit: November 11th, 2011

Italian patent extendable abroad with validly claiming priority

Inventor: Mr Fausto Garsi - Resident in Milan (Italy) Via Donna Prassede 3

Patent - Description

COLLAPSIBLE AND CONTRACTIVE ANTI ROLL BAR FOR VEHICLE APPLICATIONS

A mechanical device is applied inside the link rods and in the middle of the roll bar itself,

two relevant functions are provided as described here below:

Collapsibility: when the vehicle gets a significant bump from the road, the device collapses,

suddenly reducing the anti roll bar stiffness.

Contractiveness: a less stiff anti roll bar behaviour on the compressed side, while

maintaining the same roll bar overall characteristics in terms of stiffness. The roll centre

gets lower in turns.

Chance to have an anti roll bar with two different stiffnesses, which makes it possible to

improve the car handling performance and to increase the comfort behaviour at the same

time.

Device easily produced, low cost application.



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Device design details 1/3

Joined to the vehicle chassis

Sketch




K3

K2

K1

Link-rod device part assembly description

Device made with 3 different springs K1 – K2 – K3

K1 preloaded works for collapsibility

K2 is softer than K3 and works on the compressed side

K3 works on the side in extension (inner side in turn)


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The bar works as a traditional one in case of on phase forces

The centre of the bar gets locked to the chassis in case of opposite forces

Roll bar device part assembly description


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Link Rod device part purpose - Collapsibility function



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Link Rod device part purpose - Contractiveness function

CG = Centre of Gravity

Kroll = Roll Stiffness



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Different roll bar stiffness to equal roll angle

The contractive effect gets the Mass Centre Lower on turn, then assuming the same lateral

acceleration, the roll moment gets less because multiplied by a shorter arm due a lower Centre

of Gravity Height (CGH)

Lat G = Lateral Acceleration

CGH = Centre of Gravity Heigh

RM = Rolling Moment = Lat G * CGH

RM 1 RM 2

Lat G 1 Lat G 2

CGH 2 CGH 1 Lat G 1 = Lat G 2

CGH1 > CGH 2

RM 1 = Lat G 1 * CGH 1 > RM 2 = Lat G 2 * CGH 2

Considering a less Rolling Moment it is possible to have the same roll angle with a softer roll bar

stiffness.

STANDARD CONTRACTIVE



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Collapsibility working sketch

K1 compressed

K1 gets compressed when the force goes over the

preload.

Preload settled equal to max Force in roll stress.



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Contractiveness working sketch

K2 compressed

K3 compressed

Outer corner side Inner corner side



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Roll Bar device purpose

Undeformed bar

Deformed bar

No contractive effect because

the bar turns

Central device locks the bar to

the chassis allowing the

contractive effect



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Track test and related data



collapsible/contractive

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Track test - Reference Data 1/2

Comparison between two Formula 3 cars (Imola circuit - Italy, chicane passing through) with

and without the device installed.

Data trace, see also next page:

- BLACK – car with collapsible/contractive device

- RED – standard car without device

Trace 1 – Car speed [kph]

Trace 2 – Steering Wheel angle [°]

Trace 3 – Throttle [%] / Brakes Pressure [bar]

Trace 4 – Engine revs [rpm] / Number of gear engaged

Trace 5 – Time difference [s]




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Track test - Reference Data 2/2


standard speed

steering wheel angle

Throttle Brakes press

rpm

gear

Time difference



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New and alternative design



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New and alternative roll bar design

The contractive effect can be realized by a new and alternative roll bar design:



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New and alternative roll bar design

Two coaxial pipes connected to give different stiffness at each side.

Solution applicable in case the available link rod dimensions are not enough to install 3 springs.

Possibility to get a higher stiffness range than in the case of springs application.

Possibility to get a proper pre load on the anti roll bar.



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Preload system applied to the alternative Roll Bar

On the new and alternative Roll Bar it is possible to apply a proper preload.

The preload gives the possibility to optimize stiffness characteristics within the Roll bar range work.

Very useful on finding a fine tuning during the vehicle final set up.

The preload system design is available.



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Preload and decreasing rate characteristics

Max Force in Roll

Roll Bar Preload

F

Deflection

Standard Bar Collapsible effect

Infinite Stiffness

Possibility to have improved roll bar stiffness characteristics

Better vehicle handling and ride comfort are respectively the consequences of an

initial infinite stiffness and a softer rate over a settled level of roll force



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Simulations



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Simulations Models - Stiffness Parameters

Reference Std

Vehicle

Equivalent roll

Stiffness

Equivalent

Roll Angle

Front Antiroll Bar [Nmm/°] 3350 20100 10050

Front Spring [N/mm] 57.23 57.23 57.23

Front Pre Loaded Spring [N/mm] / 22 4

Front Pre Load [N] / 900 250

Front Drop Link Spring [N/mm] / 22 4

Rear Antiroll Bar [Nmm/°] 1800 10800 5400

Rear Spring [N/mm] 108.28 108.28 108.28

Rear Pre Loaded Spring [N/mm] / 12.5 2.27

Rear Pre Load [N] / 450 150

Rear Drop Link Spring [N/mm] / 12.5 2.27

Simulations performed, comparison between a Reference Std Vehicle and Vehicles with the following

characteristics:

Equivalent Roll Stiffness : total roll bar stiffness equal to the reference vehicle.

Equivalent Roll Angle : total roll bar stiffness in order to get an equivalent roll angle to the reference

vehicle.



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Multi Body Vehicle Model Characteristics

Total Mass 1617 [kg]

Front Track 1.658 [m]

Rear Track 1.600 [m]

Wheelbase 2.600 [m]

COG Height 0.470 [m]

Tyres Model :

Magic Formulae Tyres

Front Tyres 225/35 R19

Rear Tyres 285/35 R19



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Simulations - Results

Reference Std

Vehicle

Equivalent roll

Stiffness

Equivalent Roll

Angle

Ramp Steer Simulation

Max Roll Angle [°] 3.55 2.91 3.55

Max Lateral Acceleration [g] 1.029 1.056 / +2.62 % 1.055 / +2.53 %

COG Height in Turn [mm] 479.8 456.6 / -4.83 % 456.4 / -4.87 %

Pitch Variation in turn

Front / Rear [mm]

Total Variation ∆ nose up / down [mm] F +3.5 / R -3.8

∆ 7.3 up

F -27.0 / R -19.1

∆ 7.9 down

F -28.7 / R -17.7

∆ 11.0 down

Steering Pad Simulation

Max Roll Angle [°] 3.51 3.41 3.51

Max Lateral Acceleration [g] 1.0026 1.0033 / +0.07 % 1.0028 / +0.02 %

Comfort Road

RMS Vertical Acceleration [m/s^2] 0.247 0.1983 / -19.7 % 0.2025 / -18.0 %

Bump Ride in Turn

Max Vertical Acceleration [g] 0.1751 0.1643 / -6.17 % 0.1610 / -8.05 %

For the relevant specifications see the next page.



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Simulations - specifications

Ramp Steer

The vehicle at constant speed of 100 kph turns the steering wheel from 0° up to 120° in19 seconds

time.

Steering Pad Constant Radius

The vehicle, after a short straight, follows a 100 metres radius curve line, increasing the speed from

70 kph to 150 kph in 30 seconds.

Comfort Road

The vehicle at 70 kph constant speed rides an extra urban road profile. The road profile is in opposite

phase between the 2 car sides.

Bump Ride in Turn

The vehicle at 100 kph on turn rides a plateau profile bump only on the inner turn wheels.



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Summary



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Better Handling Performance: + 2,5 % Lateral Acceleration

Better Ride Comfort: - 18.0 % Vertical Acceleration

Better Agility Behaviour: - 4.8 % Centre Mass Height

Better Ride comfort on high bump : - 8.05 % Vertical Acceleration

Positive Pitch angle on turn: 11 mm (nose down) equal to more aero down force.

Simulations results - Summary



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Device characteristics - Summary

Better general car handling because of the lower Centre of Gravity in Turns combined with

better comfort.

Roll bar characteristics with different stiffnesses in the work range, getting the possibility to

find a better vehicle set up with different behaviours combined.

Possibility to increase the car pitch angle on turn, extremely important benefits especially

for down force vehicles.

Application suitable for all kinds of vehicles, NOT only for sport cars, even better for

vehicles such as the SUV, because of the weight , high Mass centre and big roll angle.

Fully mechanical device.

Low cost and extremely reliable.



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