How Automotive Gas Struts Work

Gas struts, also known as lift supports or lift struts, are essential parts of our cars, trucks, boats, and more. We rely on them almost daily to easily open and close the vehicle’s hood, trunk, or tailgate. However, gas strut applications go beyond just autos — you can also find these handy lift supports in lawnmowers, toolboxes, toy boxes, attic doors, concession stands, aircraft storage doors, tanning beds, and various industrial applications. 

Lift supports act as a reliable and convenient support system for doors, hoods, and more. They’re available in various styles to suit various automotive and non-automotive applications and needs. In this post, we’ll be focusing on gas struts for automotive applications and how they work. 

Why Do We Need Gas Struts?

Gas struts are necessary to create a dependable and easy way of opening trunks, hoods, tailgates, and hatches. They attach directly to the vehicle body or structure with clips or screws. The strut’s pushrod is connected internally using an operating spring that compresses when it is extended outwards from its holder (the “gas” effect). 

Gas struts are available in two different styles: pneumatic and electric. While both types operate similarly — they rely on gas pressure within the piston-type cylinder to provide stability — there are still some key differences worth noting. These include:

  • Pneumatic struts are powered by a pressurized gas system (typically nitrogen or compressed air) and require no power cord 
  • Electric struts run on a 12V battery, but this can be an expensive option for some vehicles due to the high cost of electric motors versus pneumatic systems that only need electricity as far as opening liftgates is concerned — they’re one of the many new car technologies making it easier for car owners to interact with their vehicles

Key point: The main difference between these two types is where they get their power from — in other words, whether it’s supplied with external pressure or not. Additionally, because pneumatic strut cylinders don’t need any wiring whatsoever, they’re easier and less costly to install than electrically operated units would be. 

How Gas Struts Works 

Gas struts work by compressing the gas within a cylinder. The compressed air causes pressure to build on one side of the piston and decrease on the other, creating movement in an arc-like motion. Gas struts are connected at one end with a pin or ball sockets so that they can pivot easily from their stationary positions when mounted onto brackets. 

When activated by pneumatic force or electrical current, hydraulic fluid is pumped through pressurized tubing into chambers located inside each strut, where it exerts force against pistons to move them up and down relative to cylinders attached to both ends of every strut. These compression movements create enough leverage for lifting heavy loads without bending under pressure.

Compression movements create enough force for quick response time in lift functionality, such as lifting your car’s hood or trunk, so you don’t have to wait around for long periods between movement cycles before going onto your next task.

How a Gas Strut Generates a Force

Gas struts generate force by compressing the air inside the chamber. For example, when you press on one end of a strut, it releases gas from its other side, and this causes an equal but opposite force to be exerted in turn. As long as there is enough pressure applied at either end, the air will continue to compress until all of it has been released out through the return valve, creating a vacuum that forces the piston back into place.

This process can happen very quickly because compressed air molecules are more densely packed together, so they exert greater pressure than those not yet under compression. Gas struts are designed with seals around their chambers, preventing any natural loss of fluid or leakage no matter how many times they’re used.

Gas Struts as Dampers

Gas struts can also be used as dampers, which provide a soft and controlled stop to moving objects. In this case, the gas is compressed by an external force rather than its own internal pressure. In other words, it’s externally pressurized during use. Some applications include rear-view mirrors mounted using one of these devices, so they don’t get damaged with sudden movements.  

Gas Struts as Energy Reservoirs

Gas struts are used as a reservoir of energy that is stored in the form of compressed air. Most automotive gas struts use this type of system because it is efficient and doesn’t require a lot of energy to compress the air. When activated by either pressing or pulling them down from their original position, a gas strut allows motion without requiring any additional input of physical force. That means that they have little friction-force loss and will continue to move until there is some external resistance applied. 

The effect of this self-powered movement makes it very easy to create smooth transitions between opening and closing car hoods, trunks, or tailgates. However, when they no longer work as expected, their movement fails, which can be a safety risk when you lack support when opening liftgates — check out these symptoms of bad or failing gas struts

How a Gas Strut Stores and Releases Energy

grey car with camping shed

As mentioned above, gas struts store energy in the form of compressed air. Compressed air is high-pressure, and when released, it has kinetic energy, which can be used to move objects such as a hood, trunk, or another liftgate. The benefit of using gas struts rather than other types like springs lies in how quickly they can respond to changes in pressure (usually within milliseconds) and how long their response will last before needing more pressurized air input again. 

 

How Does the Gas Stay Inside?

In order for the gas to stay inside the strut without leaking out, it needs two things: an open end through which more gas can enter and exit when needed, called the nozzle; and valves on either side of that opening — one valve opens while another closes at each point where the pressure changes (that’s what makes them “gas” struts). This way, when a load is applied, gas can flow in and out of the strut to compensate for changes. 

Why Use Gas Struts?

Gas struts are an efficient and effective way to improve the performance of your lift support needs. They’re often used in car hoods, trunks, doors, rear windows, and tailgates, where they serve as safety features that help keep them closed or open when needed. Understanding how these gas struts work is vital so you can identify when they’re no longer working efficiently. 

If your gas struts or lift supports are old, damaged, or malfunctioning, it’s time for a replacement. Just make sure to get quality replacements for your car. 


Photo Credits

Image 1: https://unsplash.com/photos/BWnHYb6kZAA 

Image 2: https://unsplash.com/photos/NfAmXcv9rVA

Author: Jordan McDowell
Jordan McDowell is a writer and automotive enthusiast. He specializes in content that helps car and truck owners get the most from their vehicles through aftermarket upgrades.

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