Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
1999-10-01
2001-02-13
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S070000, C701S071000, C073S121000
Reexamination Certificate
active
06188948
ABSTRACT:
BACKGROUND OF INVENTION
This invention relates to a process for testing an anti-lock brake system (ABS) for a vehicle after installation or work on the ABS without the need to test the vehicle for an ABS design braking event. The process involves engaging a portable computer to the electrical communication network of the vehicle and communicating with the Electronic Control Unit (ECU) or Electronic Controller Module (ECM) of the ABS. The vehicle is driven onto motorized rollers that can roll the wheels at low speeds without requiring vehicle movement. The portable computer makes a series of queries to the ECU to determine status of various parameters. Additionally, the portable computer is used to make directives to the ECU as far as cycling the ABS hold solenoids and the ABS decay solenoids and the driver as far as braking.
SUMMARY OF INVENTION
The process is essentially a closed loop test of the completely installed ABS system without actually requiring a wheel lockup at speed to test vehicle response (a “design braking event”). Prior art involved either testing the individual components during various stages of assembly or making the vehicle perform a simulated ABS design braking event to test the system on a wheel lockup.
The ABS system on the vehicle is engaged to the electrical communication system of the vehicle that currently may be a J1587 or J1939 electrical network. The ABS system contains the following components for each vehicle wheel: a wheel speed sensor; an ABS hold solenoid; and an ABS decay solenoid. All these components are electrically engaged to the ECU that will be described here as either the ECU or the ECM. The wheel speed sensor generates a signal to the ECU that is proportional to the speed in miles per hour (mph) at which the wheel turns radially. The ABS hold solenoid when closed will lock out the supply of brake actuating fluid, whether it be air or hydraulic, from activating the particular brake on a wheel. Closing the ABS hold solenoid prevents a brake for a particular wheel to be applied. The ABS decay solenoid when closed causes the brake actuating fluid, whether it be air or hydraulic, to be released from application on the brake for a particular wheel. Opening the ABS decay solenoid will cause a brake for a particular wheel to be released. Under an ABS design initiation event where a wheel is locked up, the ECU of the ABS system will cycle the hold solenoid and the decay solenoid to mitigate or release the wheel lockup.
The testing equipment required for performing the process includes motorized wheel rollers that may be controlled through an external computer such as the manufacturing or maintenance facilities main computers. The rollers may rotate one or two wheels of an axle at a time or simultaneously and each contains a counter torque measuring apparatus which measures the vehicle wheel's resistance to movement. This resistance may be brought on by application of vehicle brakes or due to mechanical binding within the axle or brake. The portable computer for engagement to the electrical communication system of the vehicle and querying the ECU is comprised of an off-the-shelf portable computer (PC) engaged to a bar code scanner for reading the vehicle identification number (VIN) and a touch control screen for operation of the PC. In the preferred embodiment, the PC has a pentium processor and the bar code scanner and the touch control screen are powered from the keyboard connector of the PC.
The process contains the following steps:
1. The vehicle is located such that the a right side and a left side wheel for one axle rest each on one of the motorized rollers;
2. The portable PC is electrically connected to the onboard electrical communication network of the vehicle, preferably by plugging a connector into an outlet in a cab of the vehicle;
3. The PC queries the ECU as to the configuration of the ABS;
4. The PC compares the configuration from the ECU with the configuration associated with the specific vehicle as provided by the main facility testing computer, which may be a main frame computer;
5. If the configuration of the ABS recorded in the ECU differs from the main frame expected configuration, the PC directs the ECU to self query the components of the ABS through the onboard network;
6. If the configuration of the ABS on of step 4. or self checked in step 5. matches with the main frame expected, the configuration passes, otherwise the configuration fails;
7. The PC directs the ECU to report battery voltage with the voltage passing if at above a preset quantitative value, preferably twelve (12) volts;
8. The PC queries the ECU for the existence of any active faults within the ECU as defined by a Society of Automotive Engineering (SAE) standard, if no faults exist the ECU passes;
9. The correctness of left/right side connections to the ECU is verified when the rollers commence slowly rolling one of the wheels, preferably the right wheel of the axle, as the PC looks for the ECU to report that only the right (rolled) wheel is rolling at a particular speed, preferably slower than five (5) mph;
10. Without the drivers foot on the brake pedal, the rollers then commence rolling both of the wheels on the axle to be tested at a similar speed while the counter torque measuring devices on the motorized rollers measure resistance of the wheels against turning;
11. If the resistance of the wheels against turning does not rise above a pre-selected value, then the axle to be tested and brakes pass the mechanical binding test;
12. The rollers commence rolling the left wheel with the PC looking for the ECU to now report that both left and right wheels of the tested axle are rolling;
13. If both steps 11 and 12. show that the expected wheels rolled as detected by the ABS then the left/right side connections are passed;
14. The PC then alternatively directs the ECU to cycle the ABS hold solenoids for each of the wheels with the PC continuously querying the ECU as to brake actuating fluid pressure for each wheel, while the hold valve is closed the PC directs the driver of the vehicle to press constantly on the brake pedal, a passing hold solenoid being one where the downstream pressure does not increase upon the application of actuating fluid on the upstream side of the hold valve;
15. The PC then directs the driver of the vehicle to press constantly on the brake pedal while the PC then alternatively directs the ECU to cycle the ABS decay solenoids for each of the wheels with the PC continuously querying the ECU as to brake actuating fluid pressure for each wheel, a passing decay solenoid being one where the actuating pressure decreases to zero upon the cycling open of the ABS decay solenoid;
16. With the motorized rollers rotating both wheels simultaneously, the counter torque measuring devices of the motorized rollers, the PC directs the driver of the vehicle to apply constant pressure on the brake pedal;
17. The main frame computer compares the counter torque measured for each wheel to determine: (a) whether the brake for each wheel is providing sufficient braking power above a preset level, and (b) to compare the braking power between the two wheels to ensure the difference between the brakes does not exceed a preset level of difference in braking power;
18. Should both sub-steps of step 17 be within the specifications, the brakes are passed;
19. The vehicle is relocated to test another drive axle of the vehicle and steps 10 to 18 are repeated for the second drive axle with additional drive axles being tested similarly; and
20. A report indicating which test, passed or failed, is issued.
21. The process may be varied without departing from the main intent of the invention that is to test an ABS system on assembly without putting the system through a design-braking event.
REFERENCES:
patent: 4024756 (1977-05-01), Cline
patent: 4192180 (1980-03-01), Gerstenmeier et al.
patent: 4805447 (1989-02-01), Meguro et al.
patent: 4912969 (1990-04-01), Ishizeki
patent: 4932252 (1990-06-01), Bovenlander et al.
patent: 5005405 (1991-04-01), Ishizeki
patent
Arthur Gertrude
Calfa Jeffrey P.
Cuchlinski Jr. William A.
Hernandez Gilberto
Navistar International Transportation Corp.
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