Vehicle height control apparatus

A vehicle height control apparatus receiving a vehicle height signal, comprising:

• height adjustment means for adjusting vehicle height using a pressurized fluid;
• pressure sensing means for sensing the pressure of the pressurized fluid and producing a pressure signal having rising and falling portions each having a slope;
• waveform shaping means for smoothing the pressure signal by decreasing the slope of the rising portion more than the slope of the falling portion, a time constant of the falling portion of said pressure signal waveform being shorter than a time constant of the rising portion of said pressure signal waveform, causing the pressure to increase by a first speed during the rising portion and causing the pressure to decrease by a second speed faster than said first speed during the falling portion;
• and
• control means for controlling vehicle height in dependence upon the vehicle height signal and the smoothed pressure signal.

A vehicle height control apparatus receiving a vehicle height signal, comprising:

• height adjustment means for adjusting vehicle height using a pressurized fluid;
• pressure sensing means for sensing the pressure of the pressurized fluid and producing a pressure signal having rising and falling portions each having a slope;
• waveform shaping means for smoothing the pressure signal by decreasing the slope of the rising portion more than the slope of the falling portion, said waveform shaping means comprising:
• a passive low-pass filter operatively connected to said pressure sensing means;
• a active low-pass filter operatively connected to said passive low-pass filter;
• and
• a pair of diodes operatively connected between said pressure sensing means and said active low-pass filter;
• and
• control means, operatively connected to said active low-pass filter, for controlling vehicle height in dependence upon the vehicle height signal and the smoothed pressure signal.

A vehicle height control apparatus, comprising:

• a height control device for controlling vehicle height with a pressurized fluid;
• a fluid pressure sensor connected to said height control device;
• a passive low-pass filter operatively connected to said fluid pressure sensor;
• an active low-pass filter connected to said passive low-pass filter;
• a pair of diodes operatively connected between said fluid pressure sensor and said active low-pass filter;
• an A/D converter connected to said active low-pass filter;
• and
• a height control circuit connected to said A/D converter and said height control device.