Suspension system with optimized damping response

• US 8,457,841 B2
• Filed: 11/14/2007
• Issued: 06/04/2013
• Est. Priority Date: 08/31/2007
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Knoll, Richard J., Moshchuk, Nikolai K., Namuduri, Chandra S., Nayak, Raviraj U., Golpe, William, Nardi, Flavio, Ryu, Jihan
• Primary Examiner(s): MANCHO, RONNIE M
• Application Number:
  US11/939,698
• Publication Number:
  US 20090062983A1
• Time in Patent Office: 2,029 Days
• Field of Search: 701/37, 701/38, 280/124.106, 280/124.158, 280/5.5, 280/5.508, 280/5.515, 280/5.503, 188/319.2, 188/266.1, 380/124.106, 380/124.158, 380/5.5, 380/5.508, 380/5.515, 380/5.503
• US Class Current: 701/37
• CPC Class Codes: B60G 17/08 Characteristics of fluid dampers adjusting fluid dampers in general F16F9/44 - F16F9/53
• CPC Class Codes: B60G 2400/202 Piston speed; Relative velocity between vehicle body and wheel
• CPC Class Codes: B60G 2500/104 continuous
• CPC Class Codes: F16F 9/44 Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction F16F9/53, F16F13/26 take precedence; temperature correction only F16F9/52

Abstract

An analytical methodology for the specification of progressive optimal compression damping of a suspension system to negotiate severe events, yet provides very acceptable ride quality and handling during routine events. In a broad aspect, the method provides a progressive optimal unconstrained damping response of the wheel assembly with respect to the body. In a preferred aspect, the method provides a progressive optimal constrained damping response of the wheel assembly with respect to the body, wherein below a predetermined velocity a conventional damper force is retained.

Claims

1. A method for providing a suspension system with optimized damper response, wherein a sprung mass is suspended by the suspension system, the suspension system including a wheel assembly having a wheel center and a mass, m, a nonlinear damper wherein the damper is connected between the sprung mass and the wheel assembly, and a spring having a predetermined spring force, F(x), as a function of displacement of the wheel relative to the sprung mass wherein the spring is connected between the sprung mass and the wheel assembly, said method comprising the steps of:

providing a substantially constant total force, F(L), on the wheel assembly with respect to the sprung mass during a jounce event over a travel length of the wheel center of the wheel assembly with respect to the sprung mass, wherein the travel length extends between zero and L;

wherein the wheel center of the wheel assembly has a velocity U_o relative to the sprung mass responsive to the jounce event at the travel length of zero, and wherein the wheel center of the wheel assembly has a velocity of zero responsive to the jounce event at the travel length of L; and

wherein F(L) is a combination of a damper force, Φ

(y), provided by the damper and of the spring force, F(x), provided by the spring, where

2. The method of claim 1, wherein the damper force is a smooth, continuous and monotonically increasing progressive optimal unconstrained damper force.

3. A method for providing a suspension system with optimized damper response, wherein a sprung mass is suspended by the suspension system, the suspension system including a wheel assembly having a wheel center and a mass, m, a nonlinear damper wherein the damper is connected between the sprung mass and the wheel assembly, and a spring having a predetermined spring force, F(x), as a function of displacement of the wheel relative to the sprung mass wherein the spring is connected between the sprung mass and the wheel assembly, said method comprising the steps of:

providing, if an initial velocity, U₀, of the wheel center of the wheel assembly relative to the sprung mass in response to a jounce event at an initial position, x₀, is less than or equal to a first predetermined wheel center velocity, u₁;

a predetermined force, φ

(y), by the damper and the spring acting in combination on the wheel assembly with respect to the sprung mass; and

providing, if the initial velocity, U₀, of the wheel center of the wheel assembly relative to the sprung mass in response to a jounce event at the initial position, x₀, is greater than the first predetermined wheel center velocity, u₁;

a substantially constant total force, C₁, by the damper and the spring acting in combination on the wheel assembly with respect to the sprung mass during a jounce event for any velocity of the wheel center of the wheel assembly greater than or equal to a second predetermined wheel center velocity, u₂, where u₂>

u₁;

the predetermined force, φ

(y), by the damper and the spring acting in combination on the wheel assembly with respect to the sprung mass for any velocity of the wheel center of the wheel assembly relative to the sprung mass in response to a jounce event in which the velocity of the wheel center in response thererto is less than or equal to the first predetermined wheel center velocity, u₁; and

a smooth, continuous and monotonically increasing transition force by the damper and the spring acting in combination on the wheel assembly with respect to the sprung mass for any wheel center velocity in response to the jounce event between velocity u₁ and velocity u₂; and

wherein said parameters are related by;

4. The method of claim 3, wherein:

u₁ generally neighbors u₂; and

u₁ is substantially equal to 2.0 m/s.