Although shock absorbers have been used for many years, engineers continue to improve them with things like gas pressurization, electronic valves, friction-reducing seals, and even magnetic repulsion technology. Nowadays, many companies are working on the next huge advance in this technology: kinetic active systems controlled by computers and sensors. Before we examine the new computerized versions, though, let’s look at how the old style works.
How shock absorbers work
Believe it or not, shock absorbers have little to do with absorbing shocks. The springs on each wheel of your vehicle, either coil or leaf-style, absorb the bumps and shocks –not the shock absorbers! What the shock absorbers do is dampen the springs’ bouncing so your vehicle does not bounce up and down after hitting a bump. Technically, shocks should be called “spring dampeners” not “shock absorbers” as they now are.
Shock absorbersuse motion dampening oil that moves from one chamber to another in the shock. The design of a shock absorber is not simple because there are really contradictory forces at work. For example, wheel impacts from a pot hole would like a light response but body roll needs a stiffer response. There is always some trade-off between the vehicle’s ride and handling.
High-tech kinetic types
The new Kinetic systems still make use of oil-filled cylinders with pistons dampening the vehicles springs but use some modern technology. To diminish the compromise between handling and ride, the creation and manipulation of damping forces are moved outside your shock absorbers. A bunch of hoses connect all four units to two hydraulic accumulators (sealed containers with oil and pressurized nitrogen enclosed). In some versions, there is also an electric pump to adjust the pressure in the accumulators.
Essentially, the eight chambers inside the four-suspension units are interconnected. The top chambers on one of the vehicle’s sides are hydraulically linked to the opposite side’s bottom chambers, and vice versa. Think about what occurs when a single-wheel bump is encountered. The suspension motion pumps oil out of one chamber into the other chamber only inside that shock absorber. Thus, only one shock absorber is involved in this ordeal.
When the car does a corner, the vehicle starts to roll and the cross-plumbing arrangement yields a response different from a one-wheel reaction. Now, oil’s outbound flow from all four hydraulic units travels into only one accumulator. The nitrogen inside acts like a spring to resist that flow. As a result, the body roll is contained and there isn’t a need for anti-roll bars.
Because the bump and roll modes act by themselves, the Kinetic system may be tuned to provide a controlled response to one-wheel bumps and body roll at the same time. Adding electronically adjustable orifices allows the damping to be matched to vehicle velocity.
Final Remarks
A shock absorber is the unsung hero of any vehicle’s suspension system. However, according to Northwest, a full-service Dodge, Chrysler, Jeep & RAM car dealer in Houston, TX, the advantages of Kinetic shock absorber systems are so strong that we should be seeing these on dozens of cars soon!