Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
1999-09-16
2001-03-20
Nguyen, Tan (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C701S062000, C477S900000
Reexamination Certificate
active
06205389
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to systems/methods for determining a value indicative of vehicular gross combined weight (GCW) in vehicles equipped with automated transmission systems or manual transmission systems and electronic data links. In particular, the present invention relates to a system/method for determining the GCW of vehicles, such as heavy-duty trucks or coaches equipped with an electronic databus carrying engine torque and other information, such as a databus conforming to the CAN, SAE J1922 and/or SAE J1939 protocol, wherein the control parameter indicative of GCW is a filtered, averaged value, often an average of 500 or more individual determination iterations, to minimize the effects of driveline torsionals, noise and the like. More particularly, the present invention relates to a GCW value determination method/system wherein the GCW control parameter is a filtered, averaged value and wherein the GCW control parameter value is reset to a default value thereof upon sensing that the current highly filtered value for GCW may be inaccurate.
2. Description of the Prior Art
In a heavy-duty truck or tractor-semitrailer vehicle, vehicle GCW may vary in a range of from about 10,000 pounds up to about 80,000 pounds or more, depending upon vehicle type and load. It is highly desirable to inform the vehicle operator of at least approximate current GCW and/or to provide this information to vehicle systems such as, e.g., an automated transmission system, a fleet management system, a variable suspension system, an onboard central tire inflation system (CTIS), an antilock brake system (ABS) or the like.
It is known in the prior art to provide various scale systems for vehicles wherein a control parameter indicative of vehicle weight, or at least of the weight of the vehicle load, may be measured. See, e.g., U.S. Pat. Nos. 4,714,122; 4,728,922; 5,014,206 and 4,839,835, the disclosures of which are incorporated herein by reference.
These systems required scale or other weighing systems which were costly to provide and/or maintain and were best suited for vehicles, such as garbage trucks or dump trucks, involved in special haulage applications, such as commercial refuse disposal or the like.
Methods/systems for calculating GCW as a function of engine/drivewheel torque and vehicle acceleration, as read from signals on a data link and/or outputted by various sensors, are known in the prior art. In one example, the GCW of a vehicle may be determined from known drive train characteristics (transmission ratio, axle ratio, tire radius, etc.), engine torque and vehicle acceleration measured at time t
1
and t
2
if t
1
and t
2
are relatively close (within seconds). This may be expressed as:
GCW=(T
1
−T
2
)÷((A
1
·A
2
)×C)
where: T
i
=Wheel torque at time t
i;
A
i
=Vehicle acceleration at time t
i
; and
C=Wheel rolling radius÷gravity constant.
To minimize the effects of drivetrain torsionals, noise and the like, GCW is, preferably, determined during or immediately after completion of an upshift and the control parameter GCW
CP
is a running, filtered average of many individual iterations of GCW determination. While the above-described methods/systems are very effective, they are not totally satisfactory as, in certain circumstances, they may not be as responsive as desired to situations wherein vehicles have stopped to change their loading, such as, for example, by adding or unloading cargo, connecting or disconnecting a semitrailer taking on or discharging coach passengers, or the like.
Automated vehicular systems using GCW as a control parameter and/or having logic for determining GCW may be seen by reference to U.S. Pat. Nos. 5,272,939; 5,335,566; 5,487,005 and 5,490,063, the disclosures of which are incorporated herein by reference.
A system for resetting the highly filtered value of GCW upon sensing conditions indicative of (i) the vehicle being at rest and/or the highly filtered value (GCW
CP
) differing from a less-filtered test value (GCW
TEST
) by greater than a predetermined value may be seen by reference to U.S. Pat. No. 5,491,630, the disclosure of which is incorporated herein by reference.
While an improvement over previous systems, the system described in U.S. Pat. No. 5,491,630 was subject to improvement, as it occasionally reset the GCW estimate when not necessary, did not always reset when required and/or reset to a test value which might not be desirable.
SUMMARY OF THE INVENTION
In accordance with the present invention, the drawbacks of the prior art are minimized or eliminated by the provision of a system/method for determination of vehicular GCW wherein the value of the control parameter outputted by the system as indicative of vehicular gross combined weight (GCW
CP
) is a relatively highly filtered, averaged value of a large number of previous (GCW
i
) determination iterations, and said value is reset to a preselected/predetermined default value upon the occurrence of conditions associated with probable vehicle change of load.
The foregoing is accomplished in a system/method for determining the value of a control parameter GCW
CP
indicative of vehicular GCW as a relatively highly filtered, averaged value of previous GCW determination iterations by (1) selecting/ determining a default value for said value, (2) calculating a test GCW value (GCW
TEST
) alongside the estimated GCW value (GCW
CP
), the test value being much less filtered and calculated on virtually every upshift, (3) comparing the estimated value to the test value to determine if the test value is within a given percentage of the estimated value (((0.5)(GCW
CP
))<GCW
TEST
<((2.0)(GCW
CP
)))?) and, if not, causing said value to be reset to the default value thereof. Preferably, the default value of GCW is equal to a relatively large GCW for the vehicle.
The default value will be selected with a view toward the system or systems using GCW as a control parameter. For example, in an automated mechanical transmission system wherein the transmission is controlled, at least in part, as a function of the value of the GCW control parameter, selecting a relatively large default value will tend to result in errors wherein shifting is somewhat aggressive, which is considered to be more desirable than errors wherein a shift expected and desired by the operator is not attempted.
Accordingly, it is an object of the present invention to provide an improved system/method for determination of the value of a control parameter GCW
CP
indicative of vehicular GCW as an average of current and multiple GCW determination iterations wherein the value of the control parameter will reset to a predetermined default value upon sensing the occurrence of a set of vehicle operating conditions predetermined to be indicative of vehicle load changes.
This and other objects and advantages of the present invention will become apparent from a reading of the detailed description of the preferred embodiment taken in connection with the attached drawings.
REFERENCES:
patent: 5272939 (1993-12-01), Markyvech et al.
patent: 5335566 (1994-08-01), Genise et al.
patent: 5487005 (1996-01-01), Genise
patent: 5490063 (1996-02-01), Genise
patent: 5491630 (1996-02-01), Genise et al.
patent: 6116105 (2000-09-01), Genise et al.
Eaton Corporation
Gordon Howard D.
Nguyen Tan
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