Active suspension system with fail-safe system capable of automatically resuming normal suspension control upon resumption of normal state operation
First Claim
1. An active suspension system comprising:
- a suspension system disposed between a vehicular body and a road wheel for damping energy for causing relative displacement between the vehicular body and the road wheel, said suspension system including means for defining a variable pressure chamber;
a fluid circuit for circulating pressurized fluid across said variable pressure chamber, said fluid circuit including a pressurized fluid source and a pressure control valve means for adjusting fluid pressure within said variable pressure chamber across a predetermined neutral pressure;
a sensor means for monitoring vehicular driving parameter affecting vehicular attitude for producing a sensor signal indicative thereof;
a power supply circuit for supplying an electric power to said fluid pressure source for driving the latter;
a detector means for monitoring state of fluid flow for detecting line pressure to be supplied to said pressure control valve higher than said neutral pressure to produce a detector signal indicative thereof;
a fail-safe valve means disposed in said fluid circuit for establishing closed circuit across said pressure control valve and said working chamber for maintaining fluid pressure in said closed circuit substantially at said neutral pressure, in response to a fail-safe command;
a fail detector means for detecting of failure of component of suspension control system to produce a fail detecting signal which is to be maintained while the faulty condition of the component of said suspension control system is maintained;
a vehicular driving condition detector for detecting a predetermined vehicle driving condition for producing a vehicular driving condition indicative signal;
a control means responsive to said sensor signal for deriving a suspension control command for controlling said pressure control valve for adjusting pressure in said variable pressure chamber for regulating vehicular height and vehicular attitude, said control unit being responsive to said fail detecting signal to produce said fail-safe command and responsive termination of said fail detecting signal for resuming normal active suspension control when and condition of absence of said fail detecting signal and presence of said vehicular driving condition indicative signal is established.
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Accused Products
Abstract
An active suspension system is provided with a fail detector for detecting failure of control system which includes sensors, control unit, control valves and so forth. Fail-safe operation is taken place by closing a fluid circuit across a working chamber in a suspension system disposed between a vehicular body and a road wheel and a pressure control valve for adjusting the fluid pressure in the working chamber, and by adjusting the fluid pressure in the closed circuit substantially at a predetermined neutral pressure. The system further includes a vehicular driving condition monitor for monitoring vehicular driving condition. When faulty condition of the control system is cured or terminated, active suspension control is resumed at a timing when the vehicular driving condition monitor detects a predetermined vehicular driving condition stable enough for permitting resumption of active suspension control.
19 Citations
16 Claims
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1. An active suspension system comprising:
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a suspension system disposed between a vehicular body and a road wheel for damping energy for causing relative displacement between the vehicular body and the road wheel, said suspension system including means for defining a variable pressure chamber; a fluid circuit for circulating pressurized fluid across said variable pressure chamber, said fluid circuit including a pressurized fluid source and a pressure control valve means for adjusting fluid pressure within said variable pressure chamber across a predetermined neutral pressure; a sensor means for monitoring vehicular driving parameter affecting vehicular attitude for producing a sensor signal indicative thereof; a power supply circuit for supplying an electric power to said fluid pressure source for driving the latter; a detector means for monitoring state of fluid flow for detecting line pressure to be supplied to said pressure control valve higher than said neutral pressure to produce a detector signal indicative thereof; a fail-safe valve means disposed in said fluid circuit for establishing closed circuit across said pressure control valve and said working chamber for maintaining fluid pressure in said closed circuit substantially at said neutral pressure, in response to a fail-safe command; a fail detector means for detecting of failure of component of suspension control system to produce a fail detecting signal which is to be maintained while the faulty condition of the component of said suspension control system is maintained; a vehicular driving condition detector for detecting a predetermined vehicle driving condition for producing a vehicular driving condition indicative signal; a control means responsive to said sensor signal for deriving a suspension control command for controlling said pressure control valve for adjusting pressure in said variable pressure chamber for regulating vehicular height and vehicular attitude, said control unit being responsive to said fail detecting signal to produce said fail-safe command and responsive termination of said fail detecting signal for resuming normal active suspension control when and condition of absence of said fail detecting signal and presence of said vehicular driving condition indicative signal is established. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 16)
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11. An active suspension system comprising:
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a suspension system disposed between a vehicular body and a road wheel for damping energy for causing relative displacement between the vehicular body and the road wheel, said suspension system including means for defining a variable pressure chamber; a fluid circuit, including a supply line for supplying pressurized fluid and a drain line for driving pressurized fluid, for circulating pressurized fluid through said supply line and said drain line across said variable pressure chamber, said fluid circuit including a pressurized fluid source and a pressure control valve means for adjusting fluid pressure within said variable pressure chamber across a predetermined neutral pressure; a first flow control means disposed in said drain line between said pressure control valve and said pressurized fluid source, said second flow control means being responsive to the magnitude of line pressure supplied to said pressure control valve for switching position between a third flow control mode for permitting fluid flow thereacross for flowing back the working fluid drained from said pressure control valve to said pressurized fluid source while said line pressure supplied to said pressure control valve is maintained at least said neutral pressure, and a fourth flow control mode for blocking fluid flow therethrough while said line pressure supplied to said pressure control valve is maintained below said neutral pressure; a sensor means for monitoring vehicular driving parameter affecting vehicular attitude for producing a sensor signal indicative thereof; a control means responsive to said sensor signal for deriving a suspension control command for controlling said pressure control valve for adjusting pressure in said variable pressure chamber for regulating vehicular height and vehicular attitude, a fail-safe valve means disposed in said fluid circuit for establishing closed circuit across said pressure control valve and said working chamber for maintaining fluid pressure in said closed circuit substantially at said neutral pressure, in response to a fail-safe command; a fail detector means for detecting of failure of component of suspension control system to produce a fail detecting signal which is to be maintained while the faulty condition of the component of said suspension control system is maintained; a vehicular driving condition detector for detecting a predetermined stable vehicle driving condition for producing a stable vehicular driving condition indicative signal; a control means responsive to said sensor signal for deriving a suspension control command for controlling said pressure control valve for adjusting pressure in said variable pressure chamber for regulating vehicular height and vehicular attitude, said control unit being responsive to said fail detecting signal to produce said fail-safe command and responsive termination of said fail detecting signal for resuming normal active suspension control when and condition of absence of said fail detecting signal and presence of said stable vehicular driving condition indicative signal is established. - View Dependent Claims (12, 13, 14, 15)
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Specification