The MacPherson strut and Air Suspension - economy class cars and sports cars

Administrator posted this 23 April 2019

The MacPherson strut — this is a type of car suspension on a shock absorption strut and telescopic damper as the upper steering pivot. Some kind of the technical design of the suspension was originally developed by Fiat engineers, however, its name and the original design were developed by the guidance of engineer E. S. MacPherson in General Motors, in the late 40s. Designed strut began to be widely implemented into cars in the 70s, and is still used for front-wheel-drive cars.

This type of suspension is widely used on cars of low and medium price category.

The presence of the shock absorption strut is the main difference and uniqueness of this type of suspension, which performs two functions: it is a bearing element and a load extinguisher during car moves. The key element of the suspension is a subframe, which is fixed to the body by means of rubber-metal silent blocks (articulated link).

So the strut is the main node of this suspension. It includes a spring and the shock absorber itself. However, there is a modification of MacPherson in which the spring and the shock absorber are separated.

Air suspension is a type of automotive suspension that uses air cylinders instead of springs. This type of suspension is applicable on premium vehicles and commercial vehicles.

Main structural parts: (1) pneumatic cylinders (one per wheel), (2) compressor, (3) receiver, (4) control system. The compressor fills the cylinders with compressed air through the receiver. Such a complex functionality determines the presence of the control system (sensors of the body level above the road, acceleration, system pressure and compressor temperature).

Modes of the suspension:

  • Normal (the smooth road with the hard surface)
  • Increased (off-road)
  • Reduced (smooth road surface and speed above 100 km/h)

PROS: MacPherson

  • Simple and compact design, easy maintenance
  • Does not require per-unit repair
  • Less unsprung weight
  • High ruggedness
  • Vertical range

PROS Air Suspension

  • Adaptation to the style and driving conditions
  • Better handling
  • Easy cornering
  • High comfort
  • Reduced vibration and vibrations of the body when driving off-road

CONS MacPherson.

  • The levels of noise take a little discomfort to the driver
  • Only applicable to passenger cars
  • Significant changes in the wheel camber during the car driving at different speeds. This type of suspension, significantly “suffers” when driving on the poor road surface and off-road
  • High load on struts

CONS Air suspension

  • Complex construction, maintenance, and costly repairs
  • Sensitive to negative temperatures