DSI Compact System Saves Weight and Space

DSI's technology is a revolutionary patented compressible fluid suspension system that fully integrates two previously distinct and separate spring and damping functions into one compact strut unit typically no larger than the traditional shock absorber. To understand the function of the DSI compressible fluid system and to fully appreciate the advantages of the DSI system, it must first be understood how the DSI spring function works and then how this spring function is integrated with the damping functions to create the DSI unit. To create the spring function, DSI’s patented system works on a simple volume/ displacement method. In the static condition, when the vehicle is stationary, the load exerted on the strut from the weight of the vehicle forces the strut rod into the pre-charged cylinder chamber filled with DSI’s special compressible fluid that acts like liquid rubber. As more of the rod is forced into the cylinder, this displacement further compresses the fluid creating an increasing pressure force that resists the further advancement of the rod into the cylinder which essentially holds or suspends the vehicle at ride height creating a static spring force.

In comparison to gas \ oil or hydro pneumatic systems, the DSI system is a major advance in efficiency regarding weight and space savings. This is because the DSI strut cylinder fluid volume is compressible as single medium acting as an integral spring/accumulator in the DSI strut, It does not need the additional compressible gas medium, or the extra weight, space envelope/ volume of separate accumulators and related hydraulic components, hoses, etc. to provide a spring force.

In a comparison of cylinder volumes at various ride frequencies, hydro pneumatic or gas oil systems, typically require at least a 30% larger space envelope and additional weight than DSI systems. The DSI System’s integration of functions also results in significant reductions in weight and space in relation to air bags, coil springs, and gas shocks with remote reservoirs.

DSI Fast Spring Response / Reduces Roll and Pitch

In dynamic situations such as bump compliance or vehicle maneuvering, which require more strut stroke and compression of fluid than static spring force, the DSI cylinder fluid is further pressurized by the load imposed from chassis weight and dynamic force, providing an advantageous rising-rate spring curve characteristic which reduces vehicle body roll and pitch without the steeper spring rates of gas/oil systems at the upper end of stroke.

DSI Fast Spring Response – No Response Lag

Perhaps one of the most important features of the DSI system is its response speed in comparison to other systems. Since the DSI strut does not have to rely on a separate accumulator to create a spring force, the DSI system does not require a hydraulic flow reaction before it starts to comply dynamic load imputs and shock impulses. Therefore, the DSI spring response is nearly instantaneous allowing the DSI system attack and reduce the forces transmitted to the vehicle chassis when they occur with no response lag. This reduces initial transmitted force and roll imputs and potential build up of sequential energy cycles that has to be absorbed in slower systems.

DSI Fast Spring Response/Fast Damping Response

The fast spring response gives the damping function a head start on bump load and shock impulse compliance that the damping function directly benefits from. Just like the fast spring response, DSI’s single fluid medium approach gives the system shock attenuation response speed. DSI’s system is superior to gas/oil systems or coil over shock arrangements because the system does not require a hydraulic flow reaction before it begins attenuation and absorption of dynamic shock impacts and various vibration frequencies.

The DSI system starts damping energy much faster in the initial bounce mode which means a significant reduction in the undamped energy and stored spring force the strut must deal in the rebound mode. Furthermore, other systems have a slower speed of response due to inherent breakaway friction and system mass inertias. They also allow greater energy force to build up before compliance can start and the damping function can begin. The DSI system's instantaneous reaction and greater damping power not only reduces the magnitude of the impact and transmitted force to the vehicle frame, but significantly reduces the number of sequential damaging impact cycles the frame is submitted. This more aggressive energy management is reason DSI systems have far less bounce cycles per single impact which translates into significant improvement in all aspects of ride and handling and increases life cycles for a variety of vehicle and sub-system components.

DSI Fast Response Extends Tire Life

The DSI system’s instantaneous reaction to dynamic loads reduces the forces which cause the tire to act like a spring in other systems. This force reduction means lower operating temperatures, fewer sidewall flexes, and smoother application of force to the ground, resulting in greater tire life and reduced rim and tire failures associated with high dynamic peak stresses and peak operating air pressures. Smoother application of force to ground means increased tractive effort, which can increase vehicle mobility and power transfer efficiency.

DSI Fast Response /High-Frequency Vibration Isolation

In applications where the coil-over shock or MacPherson strut is used, the DSI system offers superior vibration isolation. In the DSI system, the chassis rides on a column of compressible fluid, which acts as a vibration isolator itself with 25-hertz effectiveness. Steel coil springs commonly used in conjunction with separate shock absorbers and other direct connection strut systems, such as MacPherson struts, transmit forced vibration directly from the tires to the frame. Unlike DSI, these systems often require additional isolator mounts. The system does not require vibration and noise insulator interfaces.

DSI Fast Response Reduces Operating Temperature

Because of the DSI System response speed and greater damping power, its ability to reduce magnitude and cycles of energy means the DSI system can also reduce the amount of correspondent energy related heat it must deal with. This reduction in potential heat means the DSI system can provide greater continuous damping rate than other systems without the usual corresponding increases in operating temperature which produce damper fade and other heat related problems. In the DSI single media system, damping fade from aeration is also eliminated, as there is no gas to aerate. Furthermore, DSI's patented damping design provides unmatched ability to reject heat in dynamic operation. This also contributes to the DSI ability to provide continuous high performance damping rates without the fade, cavitation, seal leakage or temperature related performance and reliability problems in which other systems have been plagued.

Continuous High Performance Regardless Of Environment

DSI’s system solves the performance degradation and temperature related reliability problems that other systems still face today. The DSI system was designed for stable performance in extreme temperatures. The damping effect in the DSI system changes less from temperature than viscosity index sensitive gas/oil systems. For example, in a temperature range from 100?C to -25?C, hydraulic mineral damping oil has a viscosity change from 4 CS to 16,000 CS, whereas DSI’s fluid only varies from 400 CS to 4000 CS. This is a reduction factor of 1/4 of the viscosity index, which provides significantly fewer damping variables due to temperature variations than other systems. This design factor allows the dynamic vehicle engineers to use higher damping rates without compromise to detrimental hot or cold temperature effects. Also, since the DSI fluid is synthetic, the performance of the DSI system will not degrade over time as does a hydraulic oil based system, insuring a long, reliable service life of the DSI system regardless of environment.

Application Configuration Flexibility

The DSI System technology offers many significant advantages over other systems in compact configuration and overall systemdesign function flexibility. Configurations ranging from direct replacement of Steerable MacPhersons, Coil Overs and Double A-Arms to Swing Arm and In Arm Suspensions for tracked Vehicles have been done. The DSI System can be used in almost any type of application maximizing vehicle performance and control regardless of vehicle configuration. DSI struts can be used to work together with existing suspensions configurations usually taking the place of the standard shock absorber. In these applications, the DSI strut serves as both a powerful supplemental spring element and a high power shock absorber efficiently combining functions to resist undesirable dynamic roll characteristics. At the other end of the spectrum, DSI struts are also used as ride struts that totally replace other systems to carry all the vehicle loads and provide fast spring response and high performance damping without limitation. Due to its compact package envelope, the system can fit into a large number of potential applications, whereas with other systems the application must be built around the system.

System Configuration Flexibility

The DSI passive system can be configured for fixed loads and damping characteristics or to allow for separate adjustments in the spring and damping rates to maintain effective use of the full strut travel while accommodating variations in weight. Therefore, even in its most basic configuration, one compact system design can cover an entire range of vehicle variants providing near identical ride and performance characteristics for all versions regardless of load or weight variations.

As an additional benefit, the DSI strut unit can also be used as an actuator when a pressure/control system is added to the vehicle. Depending on the level of functionality desired to perform, DSI has developed integrated control systems to be used with the struts that will perform functions ranging from basic load leveling and height control to fully active systems to control gross vehicle motions such as roll, pitch, heave, and yaw which provide optimum vehicle control, safety, and excellent ride characteristics.

Regardless of the function level, all DSI systems offer many significant advantages over other systems in performance, ride comfort, vehicle control, compact configuration and overall system design/function flexibility. The application flexibility of DSI's smaller-lighter system makes it retro-fittable in most present vehicles and the advanced system to be utilized on future vehicle concepts.

Call or email today to find out how your project can enjoy less weight, less space required all while gaining increased performance and improved economics.


Davis Systems International
15711 Regal Hill Circle - Dallas, TX 75248

Leo Davis   214.493.1600

Gary Stecklein   713-301-8979

Haime Ortega   Haime Ortega


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