Post by Candyman on Mar 13, 2008 1:05:29 GMT -8
The PT Cruiser’s suspension mounting, body structure stiffness and suspension calibrations are tuned to minimize noise, vibration and harshness, and body lean. The MacPherson strut front suspension features a high-roll center that contributes to responsive steering while reducing body lean during brisk cornering. Low-lean geometry achieves the desired suspension handling performance. A stiff front suspension cross member attaches the front suspension to the body structure and supports the steering gear. Stiffness helps to control noise.
In the rear, coil springs support the twist beam layout. Trailing arms and a Watts linkage provide longitudinal and transverse location of the axle, respectively. The rear suspension’s transverse beam causes the tires to remain vertical relative to the road during cornering, contributing to stable handling even under loads. The rear suspension’s coil springs and jounce bumpers mount above the beam, in line with the wheel centerline, to prevent after-shake when the wheel hits a bump.
The Watts linkage is used for lateral location of the axle and includes two transverse links pivoting on the body structure at the outer end and on a third link at the inboard ends. The third link pivots at its center on the axle, moving in a vertical plane relative to the body. This system controls lateral movement of the axle. Compared to the more commonly used track bar, the Watts linkage:
* Reduces lateral suspension movement relative to the body to help minimize wheel well size
* Induces less side-to-side variation in handling
* Distributes transverse loads through two links with four bushings - rather than one link with two bushings which substantially increases lateral stiffness for more precise handling. This also reduces body structural stiffness requirements and allows the use of softer bushings, limiting the transmission of road noise and harshness
Also contributing to the solid ride and handling characteristics is the rigid support of the PT Cruiser’s body structure.
Body structure bending and natural torsional frequencies or vibrations are separated from steering column, powertrain and suspension input frequencies to enhance strength and soundness. The transmission of natural noise and vibration are reduced at each one of the 47 points between the body and these systems. Tuning each local area individually to separate its natural frequency from the input largely eliminates noise and vibration paths to the passenger compartment.
The tightly sealed body shell lowers wind and road noise as well, resulting in quiet ride through all driving ranges. This is achieved through precise dimensional control of door and liftgate openings and their sealing systems and through attention to detail on sealing body seams and other openings.
In the rear, coil springs support the twist beam layout. Trailing arms and a Watts linkage provide longitudinal and transverse location of the axle, respectively. The rear suspension’s transverse beam causes the tires to remain vertical relative to the road during cornering, contributing to stable handling even under loads. The rear suspension’s coil springs and jounce bumpers mount above the beam, in line with the wheel centerline, to prevent after-shake when the wheel hits a bump.
The Watts linkage is used for lateral location of the axle and includes two transverse links pivoting on the body structure at the outer end and on a third link at the inboard ends. The third link pivots at its center on the axle, moving in a vertical plane relative to the body. This system controls lateral movement of the axle. Compared to the more commonly used track bar, the Watts linkage:
* Reduces lateral suspension movement relative to the body to help minimize wheel well size
* Induces less side-to-side variation in handling
* Distributes transverse loads through two links with four bushings - rather than one link with two bushings which substantially increases lateral stiffness for more precise handling. This also reduces body structural stiffness requirements and allows the use of softer bushings, limiting the transmission of road noise and harshness
Also contributing to the solid ride and handling characteristics is the rigid support of the PT Cruiser’s body structure.
Body structure bending and natural torsional frequencies or vibrations are separated from steering column, powertrain and suspension input frequencies to enhance strength and soundness. The transmission of natural noise and vibration are reduced at each one of the 47 points between the body and these systems. Tuning each local area individually to separate its natural frequency from the input largely eliminates noise and vibration paths to the passenger compartment.
The tightly sealed body shell lowers wind and road noise as well, resulting in quiet ride through all driving ranges. This is achieved through precise dimensional control of door and liftgate openings and their sealing systems and through attention to detail on sealing body seams and other openings.
