ANALYZER FOR CONTROL SYSTEM WHICH REGULATES VEHICLE BRAKING

• US 3,841,712 A
• Filed: 08/01/1972
• Issued: 10/15/1974
• Est. Priority Date: 08/01/1972
• Status: Expired due to Term

• Current Assignee: Borg-Warner Automotive Incorporated (BorgWarner Incorporated)
• Original Assignee: Ronald L. Syria
• Inventors: Syria, Ronald L.
• Primary Examiner(s): Blix, Trygve M.
• Assistant Examiner(s): Kunin, Stephen G.
• Application Number:
  US05/276,981
• Time in Patent Office: 805 Days
• Field of Search: 303/21 324/34R,62R,57R,133,158MG 340/52R,52B,248A,248B,248C
• US Class Current: 303/122.08
• CPC Class Codes: B60T 2270/406 Test-mode; Self-diagnosis
• CPC Class Codes: B60T 8/343 Systems characterised by their lay-out B60T8/349 takes precedence
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: B60T 8/90 using a simulated speed signal to test speed responsive control means

Abstract

A regulated braking arrangement includes left and right sensors to provide wheel velocity signals, and a solenoid for dumping brake line pressure to prevent wheel lock-up. This arrangement is governed by a control system. An analyzer for checking the control system includes a sensor resistance test circuit for determining whether the left and right sensor resistances are between acceptable upper and lower limit values. A composite circuit tests the solenoid, both for acceptable resistance and for effective operation under low voltage. A wheel velocity signal circuit provides an artificial wheel velocity signal for passage through a wheel select gate circuit to the sensors in the control system. A deceleration function generator operates, through the wheel select gate circuit, to simulate a rapid deceleration to test the operability of the control system. A mechanical logic switch passes signals from a wheel select switching circuit to the wheel select gate circuit; this switch facilitates testing of different control systems, whether selecthigh, select-low, or wheel-by-wheel systems.

Claims

1. An anlyzer for use with a regulated braking arrangement having a control system including a power line, at least one sensor input for receiving a signal related to wheel velocity, and a pressure relief signal output connection for coupling to a solenoid winding to provide a signal which reduces braking pressure and obviates wheel lock-up, which analyzer comprises:

a sensor resistance test circuit, having an input connection for coupling to the sensor input in the control system, operative to determine whether the sensor resistance value is between predetermined upper limit and lower limit values, including a reference resistor connected to complete a voltage divider with the sensor under test, an indicator circuit, including a first transistor series-coupled with an indicator component, means including a second transistor for turning on the first transistor when the effective resistance of the sensor under test is below the predetermined upper limit value, and means including a third transistor for turning off the first transistor when the effective resistance of the sensor under test is below the predetermined lower limit value; and

a power supply stage, connected to receive power from the control system and to energize the sensor resistance test circuit.

2. An analyzer as claimed in claim 1, in which said sensor resistance test circuit further includes a first potentiometer for adjusting the predetermined upper limit resistance value of the sensor under test, and a second potentiometer for adjusting the predetermined lower limit resistance value of the sensor under test.

3. An analyzer as claimed in claim 1, and further comprising a solenoid resistance test circuit, having an input connection for coupling to the pressure relief signal output connection in the control system, operable to determine whether the solenoid resistance value is between predetermined upper limit and lower limit values.

4. An analyzer as claimed in claim 3, and further comprising a solenoid low voltage test circuit, connected to be energized from said power supply stage, and coupled to said solenoid resistance test circuit, to provide an indication of solenoid operability under low voltage conditions.

5. An analyzer for use with a regulated braking arrangement having a control system including a power line, first and second sensor inputs for receiving first and second signals related to first and second wheel velocities, and a pressure relief signal output connection for coupling to a solenoid winding to provide a signal which reduces braking pressure and obviates wheel lock-up, which analyzer comprises:

a first sensor resistance test circuit, having a first input connection for coupling to the first sensor input in the control system, operative to determine whether the first sensor resistance value is between predetermined upper limit and lower limit values;

a power supply stage, connected to receive power from the control system and to energize the sensor resistance test circuit;

a second sensor resistance test circuit, having a second input connection for coupling to the second sensor input in the control system, operative to determine whether the second sensor resistance value is between the predetermined upper limit and lower limit values;

a wheel select gate circuit, having a first input connection for receiving a wheel velocity signal, second and third input connections for receiving a deceleration signal, and a pair of output connections respectively coupled to the input connections of the sensor resistance test circuits for passing deceleration signals to the sensor inputs of the control system under test;

a wheel velocity signal generator, connected for energization from the power supply to pass a wheel velocity signal to the first input connection of the wheel select gate circuit; and

a deceleration function generator, connected to be energized from the pOwer supply, and to pass output signals to the second and third input connections of the wheel select gate circuit, for application through said gate circuit output connections to the control system sensor inputs, to simulate a deceleration signal to the logic circuits within the control system being analyzed.

6. An analyzer for use in a multi-wheel vehicle having a braking arrangement regulated by a control system which includes a power line, at least one sensor input connection for receiving an electrical signal related to the velocity of a first wheel, and a pressure relief signal output connection for coupling to a solenoid winding to reduce braking pressure in the vehicle and prevent wheel lock-up, which analyzer comprises:

a sensor resistance test circuit, having an input connection for coupling to the control system sensor input connection, including a reference resistor coupled to the sensor input connection for completing a voltage divider with the sensor under test, an indicator circuit, including an indicator component series-coupled with a first transistor between an energizing conductor and ground, to energize the indicator component when the transistor is turned on, means including a second transistor connected to receive an upper limit bias signal at one of its connections and to receive a sensor resistance signal at another of its connections to provide a signal for turning on the first transistor when the sensor resistance is less than the upper limit value, and means including a third transistor connected to receive a lower limit bias signal at one of its connections and to receive the sensor resistance signal at another of its connections, such that the third transistor remains non-conductive when the sensor resistance value is above the lower limit value, and such that the third transistor conducts to provide a signal for turning off the first transistor when the sensor resistance value is below the lower limit value; and

a power supply stage, coupled between the power line and the energizing conductor, to energize the analyzer.

7. An analyzer as claimed in claim 6, in which said sensor resistance test circuit further includes a first potentiometer for adjusting the value of the upper limit bias signal, and a second potentiometer for adjusting the value of the lower limit bias signal.

8. An analyzer as claimed in claim 6, and further comprising a solenoid resistance test circuit, having an input connection for coupling to the pressure relief signal output connection in the control system, operable to determine whether the solenoid resistance value is between predetermined upper limit and lower limit values.

9. An analyzer as claimed in claim 8, and further comprising a solenoid low voltage test circuit, connected to be energized from said power supply stage, and coupled to said solenoid resistance test circuit, to provide an indication of solenoid operability under low voltage conditions.

10. An analyzer as claimed in claim 6, and further comprising a deceleration function generator, operable to provide a simulated deceleration signal with a negative-going slope of the type which would actuate the control system under test to provide a brake pressure reduction signal, circuit means for applying said simulated deceleration signal over the input connection of the sensor resistance test circuit to the control system under test, and indicator means, coupled to the control system pressure relief signal output connection, for providing an indication that the control system is producing a pressure relief signal upon receipt of the simulated deceleration signal.

11. An analyzer as claimed in claim 6, and further comprising a power test circuit, coupled between the power line and the power supply stage, to provide an indication when the level of the voltage or the power line exceeds a preset value.

12. An analyzer for use in a multi-wheel vehicle having a braking arrangement regulated by a control system which includes a power line, first aNd second sensor input connections for receiving first and second electrical signals related to the velocities of first and second wheels, and a pressure relief signal output connection for coupling to a solenoid winding to reduce braking pressure in the vehicle and prevent wheel lock-up which analyzer comprises:

a sensor resistance test circuit, having an input connection for coupling to the control system sensor input connection, for coupling to the control system sensor input connection, including a reference resistor coupled to the sensor input connection for completing a voltage divider with the sensor under test, an indicator circuit, including an indicator component series-coupled with a first transistor between an energizing conductor and ground, to energize the indicator component when the transistor is turned on, means including a second transistor connected to receive an upper limit bias signal at one of its connections and to receive a sensor resistance signal at another of its connections to provide a signal for turning on the first transistor when the sensor resistance is less than the upper limit value, and means including a third transistor connected to receive a lower limit bias signal at one of its connections and to receive the sensor resistance signal at another of its connections, such that the third transistor remains non-conductive when the sensor resistance value is above the lower limit value, and such that the third transistor conducts to provide a signal for turning off the first transistor when the sensor resistance value is below the lower limit value;

a power supply stage, coupled between the power line and the energizing conductor, to energize the analyzer;

a second sensor resistance test circuit, having a second input connection for coupling to the second sensor input connection in the control system, operative to determine whether the second sensor resistance value is between the predetermined upper limit and lower limit values;

a wheel select gate circuit, having a first input connection for receiving a wheel velocity signal, second and third input connections for receiving a deceleration signal, and a pair of output connections respectively coupled to the input connections of the sensor resistance test circuits for passing deceleration signals to the sensor inputs of the control system under test;

a wheel velocity signal generator, connected for energization from the power supply to pass a wheel velocity signal to the first input connection of the wheel select gate circuit; and

a deceleration function generator, connected to be energized from the power supply, and to pass output signals to the second and third input connections of the wheel select gate circuit, for application through said gate circuit output connections to the control system sensor input connections, to simulate a deceleration signal to the logic circuits within the control system being analyzed.

13. An analyzer as claimed in claim 12, and further comprising a wheel select switching circuit, for providing a signal alternating at a frequency substantially lower than the switching frequency of the deceleration function generator, and a logic switch, coupled between the wheel select switching circuit and additional input connections of the wheel select gate circuit, operable to provide appropriate switching of the signals provided from the wheel select gate circuit output connections to test select-low logic control systems, select-high logic control systems, and wheel-by-wheel logic control systems.