G-Force Regulated Air Suspension System For Motor Vehicles

Technical Field My invention relates to an air suspension system for motor vehicles controlled and regulated by gravi¬ tational forces exerted on the vehicle while in motion. More particularly, my invention relates to a gravit- tational force sensor ("G" force) in a moving vehicle which is capable of regulating the air pressure in a plurality of air shock absorbers in order to keep the vehicle in balance while turning, accelerating or de- accelerating. The primary purpose of my invention is to provide motor vehicles, especially high performance automobiles, with a suspension system that will be responsive to the G-forces exerted on the vehicle during motion. It is another purpose of my invention to aid a driver control the vehicle balance in high speed turns where G-forces are centrifugal and so e- times cause a vehicle to break traction. It is yet another purpose of my invention to provide the driver a G-force meter showing at what level of G-force the vehicle may break traction.

Background Art There is a great deal of prior art dealing with vehicle suspension systems. For example, U.S. Patent No. 4,674,767 ( uroki & Sugasawa) discloses a plural-

ity of road sensors which control dampening of hydraulic shock absorbers, ϋ. S. Patent No. 4,671,534 (Yano) dis¬ closes a pressure sensor to control the damping force of each shock absorber and spring constant of air springs. In U.S. Patent No. 4,671,533 _. Asami, Ohaεhi, Onuma and Bu a disclose a suspension system regulated by a controller which measures the distance between the vehicle body and at least one of the wheels. U. S. Patent No. 4,669,749 (Tan- aka, Harara, Taniguchi, Suzumura, Tate oto and Kumagai) dis- closes fluid spring chambers arranged for respective wheels and controlled by velocity and steering angle detecting means. U. S. Patent No. 4,659,106 (Fujita, Hon a and Ogawa) discloses a telescoping suspension apparatus control¬ led by the steering mechanism. U. S. Patent No. 4,657,280 (Ohmori) discloses a detection system for bumpy road con¬ ditions as a means to control the vehicle suspension. None of these, however, utilize accelerometers (G-force sensors) in conjunction with vehicle suspension systems.

As it is perhaps well known, G-force sensors have been used for some time in missiles and spacecraft, and, very recently Zenith Corporation has developed the Auto G-Meter Model CGW-1562 for Heathkit for use in motor vehicles. This unit is commercially available in the detecting range of 0.1 to 0.8G. As it is also perhaps well known, virtually all shock absorbers on modern vehicles today are of the hydraulic type wherein fluid is forced through small orifices by a piston

and in this way dampens the action of the spring. There are also special-purpose shock absorbers on the market known as air-filled shocks, such as the Monroe Max-Air, which contains an air chamber and air-fill valve whereby air may be added or removed to raise or lower the vehicle to com¬ pensate for a load. However, conventional air-filled shock absorbers are not self-regulating with respect to G-forces on the vehicle.

Disclosure of Invention In accordance with the present invention, I have com¬ bined G-force sensors with air-filled shock absorbers where¬ by the internal air pressure of the shock absorbers is con¬ tinuously adjusted according to the G-forces on the vehicle and thereby the shock absorbers not only effectively dampen the action of the spring but also maintain proper vehicle height.

My improved air suspension system incorporates a three- way solenoid valve with an air-filled shock absorber in such a manner that when G-forces are exerted in the location of the shock absorber the valve will open and compressed air is allowed to flow into the air chamber thereby expanding the shock absorber a pre-determined amount. When G-forces are reduced the valve will open to allow air pressure to be released from the shock absorber. When G-forces are con- stant the valve will be closed to maintain constant pres¬ sure in the shock absorber.

An electronic signal processing circuit receives the signals from G-force sensors and opens and closes respective

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solenoid valves according to the extent of the G-forces measured by the G-force sensors. This feature is of par¬ ticular advantage and is a distinct improvement over certain prior art because by adjusting the signal processing cir- cuit the rate of movement of the shock absorbers can be con¬ trolled to enhance the handling performance of a particular vehicle under specific driving conditions.

Brief Description of Drawings

The details of my invention will be described in con- nection with the accompanying drawings, in which Fig. 1 is a perspective view of an automotive vehicle with a typical vehicular suspension control system in accordance with the present invention; Fig. 2 is a top elevated view of the system in Fig. 1; Fig. 3 is an enlarged detailed illus- tration partially broken away of a solenoid valve and air shock absorber; Fig. 4 is a ^" block diagram of the electronic circuits.

Best Mode for Parrying Out the Invention

Referring to Fig. 1, the standard hydraulic shock ab- sorbers of a typical automobile have been replaced with com¬ mercially available air-filled shocks 10, such as Monroe Max Air types. A G-force sensor 11 is located near the vehicle's center of gravity and is connected to electronic circuit controller 12 preferrably located on the dash board. Three-way solenoid valves 13 are attached to each air-filled shock 10 and are regulated by electrical wires 14 from the controller 12. Compressed air lines 15 connect the valves 13 with an air tank 16 fed by a compressor 17.

Referring to Fig. 2, the preferred location of the compressor 17 and air tank 16 are located in the vehicle trunk. There are several commercially available compres¬ sor and air tank units which will operate on 12 volts when the igition is on and are self-regulating with respect to tank pressure. The air pressure lines 15 may be of rein¬ forced flexible tubing. 10a is shown in detail in Fig. 3-

Referring to Fig. 3. an enlarged, patrially broken away view of the right rear air-filled shock 10, many of which are equipped with a threaded air-inlet/outlet stem 18 onto which a three-way solenoid valve may be attached 13. The spool-type solenoid valves, such as the Skinner Air Control Valve provides for either actuation or non- actuation of coil 19 which selects air input 15 or air release 20 through the stem 18 and, therefore the polarity of the coil in relation to the controller 12 is important.

Referring to Fig. 4, a block diagram shows the primary signal from the G-force sensor 11 received by a sample and hold amplifier 21, which is part of the controller 12. A continuous signal source 22 serves as a primary clock to measure the rate of change in the signal from the G-force sensor 11 and the sample and hold amplifier 21 differenti¬ ates the signals passing an output signal to the analog to digital converter 23 and then on to a digital display 24. The output signal from the sample and hold amplifier 21 is also passed to the signal processing circuit 25 which opens and closes the three-way solenoid valves 13 according to the rate of change the primary signal is received.