Post: Types of vehicle shock absorbers

Basic double barrel
This device, also known as a “twin-tube” shock absorber, consists of two nested cylindrical tubes, the inner tube is called the “working tube” or “pressure tube” and the outer tube is called the “backup tube”. There is a compression valve or foot valve at the bottom inside the unit. As the piston is forced up and down by bumps in the road, hydraulic fluid moves between different chambers through small holes or “ports” in the piston and through valves, converting the “impact” energy into heat, which must then be dissipated .
double tube inflatable
This variation was known as an “air chamber twin-pipe” or similarly named design, and it represented a significant improvement over the basic twin-pipe form. Its overall structure is very similar to a double tube, but low-pressure nitrogen is added to the stock tube. The result of this change is a significant reduction in “bubbles” or “gassing,” which is the undesirable result of twin-pipe overheating and failure that manifests as bubbling hydraulic fluid dripping out of the assembly. Twin-tube gas-filled shock absorbers represent the vast majority of original modern vehicle suspension arrangements.
position sensitive damping
This design, often referred to simply as “PSD”, is another evolution of the twin-tube shock absorber. In the PSD shock, which still consists of two nested tubes and still contains nitrogen, a set of grooves are added to the pressure tube. These grooves allow the piston to move relatively freely during its mid-stroke range (i.e., most common street or highway use, what engineers call the “comfort zone”), and when the piston begins to move up and down with greater intensity (i.e., during Bumpy Sections – Reinforcement allows the driver to have greater control over the movement of the vehicle, hence its extent on either side of the comfort zone (called the “control zone”), in response to movement towards more irregular surfaces, where its freedom of movement increases Greatly reduced. This advancement enables automotive designers to build shock absorbers for a specific make and model of vehicle, taking into account the specific vehicle’s size and weight, maneuverability, horsepower, etc. to produce a correspondingly effective shock absorber.
Acceleration sensitive damping
The next stage in shock absorber evolution is to develop a shock absorber that can not only sense and respond to changes in conditions from “bumpy” to “smooth” but also provide near-instantaneous reactions to individual bumps in the road. This is achieved by changing the design of the compression valve, known as “acceleration sensitive damping” or “ASD”. Not only does this lead to the complete disappearance of the “comfort versus control” trade-off, it also reduces vehicle pitch when braking and roll when cornering. However, ASD shock absorbers are usually only available as an aftermarket change to the vehicle and are offered by only a few manufacturers.
Coiled tooth shock absorber
Main article: Coiled shock absorber
The coilover shock absorber is usually a double-cylinder gas-filled shock absorber with a built-in coil road spring. It is common in the rear suspension of motorcycles and scooters, and is also widely used in the front and rear suspension of automobiles.