On "VZN" Smart and Cheap Shock Absorber Concept

Document Number: 2009-01-0220

Date Published: April 2009

Author(s):
Adrian Ioan Niculescu - Institute of Solid Mechanics
Dan DUMITRIU - Institute of Solid Mechanics
Tudor SIRETEANU - Institute of Solid Mechanics

Abstract:
¿VZN¿ is an automotive smart shock absorber concept, this acronym being abbreviation for VARIABLE ZETA NECESSARY for well behavior in all road and load conditions, where ZETA represents the relative damping, which is stepwise changed automatically, according to the piston position. The self adjustable shock absorber VZN, realized without electronics or mechanisms, grant with European Patent EP 1190184 B1, and Romanian Patent 118546 B1, has an energy dissipation system made of an inner cylinder having sideways damping valves, placed optimally between to the ends. Comparative with standard shock absorbers having constant rebound/compression damping coefficients, the VZN concept, give a wide range of damping coefficients along the stroke. So for identical damping valves/metering holes the damping coefficients decreases with the square number of active valves/metering holes, meaning values between (0.1 to 100)x (Standard damping coefficients), and more. The theoretical and by simulation results denotes the VZN concept confers, the next advantages relative to the standard ones: ¿ May be realized in much technical solution, with planar, curved, or cylindrical filling valves ¿ Permit more 70% reduced compression and rebound stopper bumpers ¿ Are cheaper and more compact and robust ¿ Give a progressive anti-unbalance effect at bounce, pitch and roll more 1 to 30 times relative to standard one, due to the high progressive vertical forces at bounce and high progressive torques at pitch and roll, on unbalance movement, confer by the large area of shock absorbers progressive vertical forces, stopping progressive the unbalance movement, at bounce, pitch and roll. ¿ Give a progressive anti-redressing effect at bounce, pitch and roll less 0.3 to 1 relative to standard one, due to the low progressive vertical forces at bounce and low progressive torques at pitch and roll, on redressing movement, confer by the large area of shock absorbers progressive vertical forces, favoring the redressing movement, at bounce, pitch and roll. ¿ Touches very rarely and softly the stop bumpers, at high roads unevenness ¿ Reduce car body highest vertical accelerations values 5 times ¿ Reduce the standard deviation of car body vertical accelerations more 40% ¿ Reduce highest forces in stop bumpers values more 20 times ¿ Reduce the root mean squares forces in stop bumpers values more 10 times ¿ Are efficient even 50% efficiency ¿ Give sufficient efficiency even 50% oil losses. ¿ Give the SKYHOOK behavior The paper present the representative technical drawings e.g. solution with planar and cylindrical filling valves-world novelty, theoretical and practical results, denoting the ¿VZN¿ concept is a great future automotive opportunity giving a semi-active damper at price of standard shock absorber.

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See other papers presented at SAE World Congress & Exhibition, April 2009, Detroit, MI, USA, Session: Steering and Suspension Technology Symposium: (Part 2 of 2) Suspensions

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