Suspension systems manage the necessity of providing trip comfort and stableness to a car through uneven ground. As a result there will vary types of suspension that handle different requirements using different methods.
As such, through another few pages the different types of suspension and the various types of anti-roll systems will be discussed.
There are a number of different suspension concepts in the market, each of them are unique in their own, hence strictly classifying them would require to say each of the suspension used in the marketplace for the different manufacturers, models and aftermarket options available. A more reasonable way to classify suspension system systems is by handling the system used to dampen the vehicle, such is the way used in this report to illustrate the available systems in the market.
A conventional suspension uses a planting season to provide the tightness of the suspension and a great shock absorber to mitigate the vibration aftereffect of the planting season.
The most common conventional suspension system is a coil-over; this is a coil spring and coil more than a damper. Even though the coil-over is the most common type of regular suspension, there are other alternatives such as utilizing a leaf springtime or in the case of a multi-link suspension, using the spring and the damper in two different places.
The main advantage of this technique is that it's a cheap and cost efficient way to provide suspension.
On the other hand this system must compromise between suspension rigidity for cornering and trip comfort.
Electric suspensions systems use electricity or magnets to dampen the automobile. This technique could entirely replace a typical suspension, of utilize a modified damper with the purpose.
The main benefit of this technique is that is a intensifying system that provides more trip comfort and a stiffer suspension system than a conventional depending on travelling situation.
The main disadvantage is that is more costly and heavy than a conventional suspension system.
A hydraulic suspension uses a pressurized liquid to alter the suspension stiffness. Because so many non classic suspensions, this system could entirely replace a typical suspension or utilize a modified conventional suspension.
As with most non typical suspensions journey comfort and suspension stiffness is advanced at the price of a far more expensive, complicated and heavier mechanism.
A hydro-pneumatic suspension is a suspension that uses the properties of gas to provide ride comfort (gas being less stiff than a conventional springtime), and the properties of fluids to provide cornering abilities (liquids being practically incompressible are stiffer than metal springs).
The main advantage of this system is that delivers both a superior ride comfort at the same time that can provide an extremely stiff suspension for cornering. Another good thing about this technique as well as the rest of the smooth suspensions (hydraulic and pneumatic suspensions) is the fact some of the current systems on the market are also capable of self-levelling the vehicle independently of the vehicle load and weight distribution as well to be able of providing variable ride level.
So many advantages also have several downsides. Generally hydro-pneumatic suspensions are complicated and expensive packages that have problems with the situation of ride elevation drop, brake electricity and ability steering performance drops if failing in the suspension system system were to occur (Actwin, n. d. ).
Pneumatic suspensions use gas (generally air, but sometimes compress and stored hydrogen or nitrogen can be used) attempt to achieve the effects of your hydro-pneumatic suspension whist reducing the expenses, weight and complication of the system.
Whist holds true that these suspension system systems achieve a good drive quality, it isn't significantly much better than a conventional suspension. One of the key problems of this type of suspension system is that the machine can be easily damaged if not installed and managed properly as leakages can occur from the air hand bags, air lines or the compressor-drier system.
In-wheel suspension is a fresh design that several companies are looking into where all the suspension system components are assembled either on the steering wheel rim or in the space inside the wheel rim.
In the pursue of providing drive comfort at the same time as cornering performance the motor vehicle industry is rolling out an array of anti-roll systems to lessen or counteract the rocking of the chassis during cornering because of the use of a soft suspension system for drive control.
Although different companies and manufacturers are suffering from several systems all of them could be categorised by the degree of relationship with the body roll.
Passive anti-roll systems are systems that are completely opposing body move. The most common unaggressive systems are anti-roll pubs and torque forearms, so these systems whilst being quite economic improve the cornering performance at the price of reducing the trip comfort.
Semi-active anti-roll systems do not fully counteract body move, instead by changing what sort of suspension system works (usually stiffening the suspension system) they oppose the pushes that generate body spin, therefore lessening the rocking effects. This system handles to lessen greatly the body roll without reducing the drive quality, but needs an additional source of power to operate the machine.
Active anti-roll systems operate not by opposing the moving causes but instead by counteracting them. So the body spin is more manipulated than with a semi-active system and no compromise is manufactured with ride comfort. The primary down sides are that active systems are heavier, more complicated and expensive and have higher power consumption than semi-active anti-roll systems.
It is worth noting that some suspension types sometimes offer features such as self-levelling or ride height control. As a result here some of the most typical ones will be described
Self-levelling: the power of a suspension system to give a flat (levelled) system for the vehicle, independently of the automobile load and weight distribution.
Ride elevation control: the ability of a suspension to change the bottom clearance.
Pitch control: the ability of a suspension system to improve the suspension adjustments to provide a flat system to counteract the front dipping or bringing up credited to braking and accelerating.
Yaw control: the power of a suspension system to combine self-levelling and pitch control to counteract the body movements whilst braking and cornering at the same time.
Suspension tightness control: the ability to modify the firmness of any suspension to suit driver requirements, usually in a range between soft-comfort and hard-sporty
Depending of the manufacturer this systems can be completely included on the suspension of be self-employed but employed in conjunction with the suspension
BMW uses a dual suspension system system; firstly the EDC (Electronic Damper Control) alters the suspension system stiffness through electronically managed dampers, and second of all an active move stabilizer system called Active Drive controls the body roll through a couple of actuators that control the stabilizers (torque hands) is a similar fashion as the Range Rover system does indeed. The BMW suspension system system features self-levelling, pitch control and yaw control suspension system (BMW, n. d. ) (BMWUSA, n. d. ) (Meeknet, n. d. ).
Figure BMW Dynamic Move Stabilization Actuator Diagram (BMWUSA, n. d. )
Figure Electronic Damping Control Diagram (BMWUSA, n. d. )
Porsche top of the range suspension system for the Cayenne model offers air suspension coupled with two other systems. First of all the PASM (Porsche Working Suspension system Management) system manages the stiffness and settings of every damper through management of mid-air suspension, and second of all the PDCC (Porsche Dynamic Chassis Control) system regulates the body move through a hydraulic system that operates the front and rear dynamic anti-roll bars (torque arms). This suspension features pitch control, dynamic anti-roll control, yaw control, drive height control and self-levelling (Porsche, n. d. ) (Beechmontdata, n. d. ).
Figure Porsche Active Suspension Management (PASM) Detail (Porsche, n. d. )
Mercedes-Benz uses the ABC (Active Body Control) active suspension that features pitch and roll control, self-levelling and ride elevation adjustable suspension system achieved through servo actuated hydraulics. In this value the system is comparable to the current found in the number Rover, but this system rather than using actuators, runs on the modified suspension strut. The ABC suspension strut replaces the conventional dampers with electronically managed plunger cylinder dampers whilst retaining the coil-over. The device woks in a similar manner, the sensors and accelerometers measure the situation and the engine oil pump send the pressure necessary to operate the suspension system, but rather than using a solo valve stop and two actuators, the ABC system runs on the front and back servo-valves that in turn sent the petrol to each of the four plunger cylinder dampers (Autoweb, n. d) (Worldcarfans, 1999).
Figure Mercedes-Benz ABC System Structure (Worldcarfans, 1999)
MagneRide is a Magneto Rheological (magnetic and hydraulic) suspension system produced by Delphi, and nowadays sold to BWI (Beijing Western Establishments) group.
The Magneto Rheological suspension is a semi-active suspension that alters the suspension system stiffness of the smooth inside the dampers through electromagnets. This technique although being a semi-active suspension can perform almost as well as a dynamic suspension system. Unlike a semi-active suspension system the control of the suspension system tightness can be evolved nothing linearly to the insight response, hence instead for example instead of opposing your body roll, it can be counteracted by further increase of the suspension system stiffness.
Figure MagneRide Suspension system (BIWGroup, n. d. )
This suspension has been fitted to some top of the range vehicles from the following companies Acura, Audi Buick, Cadillac, Corvette, Holden, and Ferrari (BIWGroup, n. d. ).
Lexus uses a suspension system system called Working Stabilizer Suspension system System that is the result of a jv between Toyota and Aisin Seiki Co. to build up an innovative suspension for Lexus (Toyota's luxury range of vehicles). The machine is a fully electrically controlled dynamic suspension system. The way it works is comparable to the one currently utilized by Jaguar-Land Rover, but rather than by using a hydraulic system, is using brushless motors geared and connected to the stabilizer pubs (torque forearms).
Toyota claims that this system is twenty times more energy conserving than a standard servo actuated hydraulic lively suspension and its effect time is also quicker, being considered to be within 20 milliseconds (Suzuki et all, 2006).
Figure Dynamic Stabilizer Suspension system System Put together (Suzuki et all, 2006)
The Hydractive system is a Citroen developed hydro-pneumatic suspension system currently used by some autos from the PSA Peugeot Citroen group, where the conventional coil springs and great shock absorbers have been changed by hydro-pneumatic distress absorbers. This system features self-levelling, ride height adjustment and automatically cutting down the ride height above certain speed to reduce gasoline consumption. Electronic control buttons avoid the suspension dropping after the engine is switched off because of the lack of anti-roll pubs. The PSA group offers another bundle with the Hydractive suspension called Activa which really is a yaw control device incorporated in the suspension (Actwin, n. d. ).
Figure Citroen Hydractive Suspension Diagram (Actwin, n. d. )
Bose's active suspension system is a cross between an in-wheel device and a conventional suspension system, which is installed upgrading a conventional coil-over planting season damper (which consists of own damper and torsion arm to aid the weight of the automobile and minimize the suspension system vibration). What sort of device works is by updating the conventional distress absorbers and spring and coil dampers by an individual linear electromagnetic motor at each steering wheel. These electromagnetic motors are computer managed to provide a soft suspension system, but at exactly the same time provide self-levelling, pitch control, yaw control and anti-roll (Bose, n. d. ).
Figure Bose's Active Suspension system Diagram (Bose, n. d. )
Michelin is rolling out its own in-wheel suspension system system. The system is a fully electrically operated suspension with a coil spring that is able to house a wheel onboard traction force and suspension system system as shown in the picture below.
Figure Michelin Dynamic Steering wheel Picture (Michelin, 2008)
This suspension system system is a mixed traction and suspension system electrical system that as Michelin cases maybe it's used in a four wheel drive or a two wheel drive structure depending on electricity demands (Michelin, 2008).
Ride Elevation Control
Hydraulically controlled torque arms through the pump and two actuators
Electronically controlled dampers
Hydraulically controlled torque arms by way of a pump and two actuators
Hydraulically controlled torque arms by way of a pump and two actuators
Hydraulic controlled plunger cylinder dampers
Hydraulically handled plunger cylinder dampers through the pump and a entrance and back servo valves
Electrically managed magneto rheological dampers
Electromagnetically controlled damper substance and damper stiffness
Electrically managed torque arms through brushless motors and lowering gears
Pneumatically controlled hydro-pneumatic suspension system struts via an air pump and up to nine nitrogen to suspension system liquid "sphere" chambers and forward and back anti-roll bars
Four computer managed electromagnetic motors upgrading the conventional suspension struts