(12) Unlted States Patent
`Kapolka
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,084,735 B2
`Aug. 1, 2006
`
`USOO7084735B2
`
`(54) REMOTE VEHICLE SECURITY SYSTEM
`
`Inventor; Michael Kapolka, Sterling Heights, IVH
`(Us)
`
`i
`_
`(73) Asmgnee.
`
`(*0 Notice:
`
`-
`IDSC Holdlngs, LLC., Kenosha, WI
`(U )
`Subject to any disclaimer, theterm ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 244 days.
`
`(2]) App]. No.: 10/229,757
`
`(22) Filed:
`
`Aug. 28, 2002
`
`(65)
`
`Prior Publication Data
`
`51
`
`(
`
`US 2004/0041691A1
`I
`Cl
`nt.
`.
`) G053 19/00
`G06F 7/00
`G083 29/00
`
`Mar. 4, 2004
`
`(2006.01)
`(200601)
`(2006.01)
`
`............ .. 123/335
`
`9/1998 Bayron et a1.
`5,803,043 A
`9/1998 Iu
`5,815,822 A
`............. .. 701/2
`11/1998 McElroy et a1.
`5,835,868 A
`11/1998 Chakraborty et a1.
`..... .. 180/169
`5,839,534 A *
`5,852,330 A * 12/1998 Yumoto .................. .. 290/40 R
`5,937,823 A *
`8/1999 Reeder et a1,
`............ .. 123/335
`6,060,981 A
`5/2000 Landes
`6,091,340 A
`7/2000 Lee et a1.
`2:122:21; 2 * 13/3888 12:11:61::::::::::111.5333???
`6,232,874 Bl
`5/2001 Murphy
`.................... .. 701/93
`6,246,948 B1*
`6/2001 Thakker
`
`. 340/426.11
`6,664,888 B1* 12/2003 Bishop .... ..
`6,876,914 B1*
`4/2005 Dubois ...................... .. 701/93
`
`EP
`GB
`
`FOREIGN PATENT DOCUMENTS
`0 681951 A1
`11/1995
`2 340 974 A
`3/2000
`
`WC
`
`“001
`WO 01/38145 A1
`OTHER PUBLICATIONS
`International Search Report for International Application
`No. PCT/USO3/26503 (5 sheets).
`.
`.
`‘
`International Search Report for Internatlonal Apphcatlon
`
`(2006.01)
`H04Q 9/00
`(52) US. Cl.
`..................... .. 340/5.5; 340/5.64; 340/466
`(58) Field of Classification Search ................. 340/55,
`340/825.69, 825.72, 825.22, 5.64, 463, 464—467,
`340/905, 932, 396; 307/103, 10.5; 701/29,
`701/35, 93, 97
`See appllcatlon file for complete search h1story.
`
`* cited by examiner
`.
`.
`.
`.
`Primary Exammer—Mlchael Horablk
`Assistant Examiner—Nam Nguyen
`(74) Attorney, Agent, or Fzrm—McDonnell Boehnen
`Hulbert & Berghofi' LLP
`(57)
`ABSTRACT
`
`(56)
`
`References Cited
`us. PATENT DOCUMENTS
`
`2 : lg; Xitcilzlll et al‘ """"""
`
`9
`a
`0 e
`. ........... ..
`5,429,089 A *
`7/1995 Thomberg et a1. .......... 123/352
`5,708,308 A
`1/1998 Katayama et a1.
`5,717,387 A *
`2/1998 Suman et al. ............... .. 701/36
`5,798,575 A *
`8/1998 O’Farrell et a1.
`........ .. 307/101
`
`A system and method for selectively limiting at least one
`operational characteristic, such as maximum speed, of a
`vehicle. A vehicle limitation control signal is supplied to the
`vehicle over a Wireless communication network. Inresponse
`.
`.
`.
`.
`.
`to
`1181118“?dcoerI Slgnal’ the maxmmm Speed Ofthe
`Ve 1° “3 “m e '
`
`33 Claims, 7 Drawing Sheets
`
`1
`
`I
`
`<———->
`
`Wireless
`Network
`
`<—-—>
`
`—i_'
`
`7_ __ I f:
`a 5
`
`UNIFIED 100 l
`
`

`

`U.S. Patent
`
`Aug. 1, 2006
`
`Sheet 1 of 7
`
`US 7,084,735 B2
`
`
`
`sage:2022,
`
`@5552:8
`
`322:5
`
`NF
`
`838
`
`m=_>_8¢x._§_m
`
`FINE
`
`
`
`
`

`

`US. Patent
`
`Aug. 1, 2006
`
`Sheet 2 of 7
`
`US 7,084,735 B2
`
`19
`
`39
`
`IFig -3
`
`To ECM
`
`
`Primary Pulse Train
`(from Throttle Postition Sensor)
`in synch with secondary
`pu|se Train (from MPU)
`
`‘
`.
`Initial Engagement
`of Vehicle Limitation Mode
`
`360°,"an
`Pulse Train In Control
`(Steady State
`Vehicle Limitation Mode)
`
`
`
`Throttle Position
`Sensor Pulse Train
`"Primary Pulse Train"
`
`Security Device Signal
`MPU "Secondary"
`Pulse Train
`
`

`

`US. Patent
`
`Aug. 1, 2006
`
`Sheet 3 of 7
`
`US 7,084,735 B2
`
`
`
`
`
`Test for Vehicle
`Limitation engage/
`disengage
`command
`
`412
`
`
`
`Start 250 ms
`broadcast timer
`
`402
`
`404
`
`YES
`
`406
`
`Reset 250ms
`Broadcast Timer
`
`and Test J1922
`
`Vehicle Limitation
`
`Flag
`
`
`
`
`414
`
`
`
`Engage Vehicle
`NO
`
`Limitation
`
`?
`
`418
`
`Set J 1922 Vehicle
`Limitation Flag to
`l1!
`
`Set J1922 Vehicle
`Limitation Flag to
`'0'
`
`
`
`ln Vehicle
`Limitation Mode
`
`?
`
`
`
`
`
`
`
`Send J1922
`Transmtssron to
`
`Powertrain
`
`Message
`
`
`
`

`

`US. Patent
`
`Aug. 1, 2006
`
`Sheet 4 of 7
`
`US 7,084,735 B2
`
`+5
`0
`
`® 3
`
`® 3
`
`50
`
`48
`
`PWM WM
`_
`PWM Sense
`input
`
`22
`
`UART
`
`26
`
`30
`
`34
`
`RS 485
`Interface
`J1708
`Vehicle Limitation Si nal
`29
`9
`
`19
`
`CR1A ®
`.
`°
`
`To Throttle Pedal
`42
`
`From Throttle
`
`J2A
`
`Throttle
`Pedal
`
`WA
`4
`
`40
`
`“A
`:S— V+ From ECM +
`J13
`I
`Engrne ECM
`
`T ECM Th ttl P 't' T
`I”
`1
`
`r0 9 osr ron
`P“
`
`52
`
`0
`
`Wiper
`
`AND
`
`CRZA
`'
`
`-
`
`J23
`
`54
`
`® CR1B
`°
`(,5) 0
`
`CRZB
`
`MA
`
`J4B
`
`46
`
`To Cruise
`Control Switch
`
`From Cruise
`Control ECM Output
`
`
`
`

`

`US. Patent
`
`Aug. 1, 2006
`
`Sheet 5 of 7
`
`US 7,084,735 B2
`
`702
`
`
`
`
`Vehicle Limitation
`Module Mainline
`
`
` 704
`
`
`
`Perform Reset Functions
`
`706
`
`
`
`
`
`708
`
`Disable Vehicle
`Limitation
`(Clear Vehicle Limitation
`Flag and
`Disengage Flag)
`
`
`
`
`
`
`710 Read Vehicle
`
`
`Message Queue
`
`Limitation Status
`Line and/or J1708
`
`
`
`Status
`
`New Message!
`
`712
`
`
`
`
` E
`
`
`718
`
`Clear Vehicle Limitation
`Disengage Flag;
`Set Vehicle Limitation Flag;
`Perform Appropriate
`Vehicle Limitation Function
`
`Engage/Disengage
`Message
`?
`
`"gage
`
`Disengage
`
`Set Vehicle
`
`Limitation Disengage Flag
`
`
`
`
`is Vehicle Limitation
`
`
`
` Disengage = 1
`
`
`
`
`
`

`

`US. Patent
`
`Aug. 1, 2006
`
`Sheet 6 of 7
`
`US 7,084,735 B2
`
`PWM TPS Vehicle
`Limitation Flowchart
`
`902
`
`904
`
`Resistive Tps
`Vehicle Limitation
`Flowchart
`
`Set D/A output to
`+5 Volts
`
`Measure current
`PW being output
`byTPS
`
`Set output to AND
`gate high
`
`Energize CR2
`
`
`
`is obtained
`
`Energize CR1
`
`Gradually reduce
`“A OUiPUtVOItage
`to setting for
`desired RPM
`
`On Rising Edge of
`TPS PWM signal, Set
`input to AND gate high
`and start one shot timer
`
`When One-Shot
`Timer times out,
`set AND gate input low
`
`Slowly decrease PWM
`signal to And gate until
`target duty cycle
`
`

`

`US. Patent
`
`Aug. 1, 2006
`
`Sheet 7 of 7
`
`US 7,084,735 B2
`
`+5
`0
`
`22
`
`® 3
`
`®
`®
`
`30
`
`34
`
`26
`
`66
`
`50
`
`48
`
`Ignition Status Q4;
`_ Vehicle Limitation Signal
`PWM Sense
`'22
`Input
`
`D/A
`4
`
`40
`
`l
`
`V F
`
`ECM
`
`+ rom +
`
`_
`
`Engine ECM
`To ECM Throttle Position T»
`Input
`52
`
`From Cruise
`Control ECM Output
`
`T0 Throttle Pedal
`42
`
`CR1A ®
`.
`'
`9
`
`-
`
`J1A
`-
`_
`J13
`
`FmWhmflle
`
`lper
`
`44
`
`'
`® CRlB
`
`°
`® 0
`
`CR2A
`-
`
`2 0'
`'
`
`54
`
`J4A
`
`J43
`
`Throttle
`
`Pedal
`
`46
`
`To Cruise
`Control Switch
`
`Vehicle Speed
`Sensor +
`
`Vehicle Speed
`Sensor -
`
`

`

`US 7,084,735 B2
`
`1
`REMOTE VEHICLE SECURITY SYSTEM
`
`TECHNICAL FIELD OF THE INVENTION
`
`The present invention relates generally to the field of
`selectively limiting one or more operational performance
`characteristics of a vehicle.
`
`BACKGROUND OF THE INVENTION
`
`An owner or operator of a vehicle may desire to limit the
`operational performance of his/her vehicle for many rea-
`sons. For example, in the event of a security breach, such as
`a car-jacking or other similar circumstance, the owner or
`operator of his/her vehicle may find it desirable to be able to
`cause the vehicle to enter a limited operational mode
`whereby the operational performance characteristics, such
`as maximum speed, is limited. In this way, certain security
`breaches in an automobile may be averted or, at least, the
`resulting negative effects minimized. The desirability of
`being able to limit the operational performance of a vehicle
`is even more acute for an owner of a fleet of commercial
`vehicles, such as commercial trucks and the like, which are
`very expensive and commonly carry expensive and/or haz-
`ardous cargo, and which are normally driven by employees.
`
`SUMMARY OF THE INVENTION
`
`The present invention relates to a new system and related
`method for limiting the operational performance of a
`vehicle. In one embodiment of the invention, one or more
`operational performance characteristic, such as maximum
`vehicle speed, of the vehicle can be selectively limited in
`response to a remotely-issued vehicle limitation control
`signal communicated to the vehicle over a wireless com-
`munication network. The vehicle includes a device for
`
`receiving the control signal, and, based thereon, limiting a
`performance characteristic of the vehicle. A variety of sys-
`tems and methods are employed to limit the speed of the
`vehicle in response to the vehicle limitation control signal
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 illustrates an exemplary environment in which the
`present invention can be implemented.
`FIG. 2 illustrates an exemplary command device accord-
`ing to an embodiment of the invention.
`FIG. 3 illustrates a first exemplary embodiment of the
`invention.
`
`FIG. 4 sets forth a flowchart illustrating an exemplary
`algorithm that could be used to implement the first exem-
`plary embodiment of the invention.
`FIG. 5 illustrates a second exemplary embodiment of the
`invention.
`
`FIG. 6 illustrates an exemplary primary pulse train pro-
`duced by a throttle position sensor and an exemplary sec-
`ondary pulse train produced by an MPU, according to an
`embodiment of the invention.
`
`FIG. 7 sets forth a flow chart that illustrates an exemplary
`algorithm that could be used to implement the second
`exemplary embodiment of the invention.
`FIG. 8 sets forth a flow chart that illustrates an exemplary
`algorithm that could be used to implement the second
`exemplary embodiment of the invention.
`FIG. 9 sets forth a flow chart that illustrates an exemplary
`algorithm that could be used to implement the second
`exemplary embodiment of the invention.
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`2
`FIG. 10 illustrates additional features that could be used
`in connection with an embodiment of the invention.
`
`DETAILED DESCRIPTION OF AN
`EMBODIMENT
`
`The present invention relates to limiting one or more
`performance characteristics of a vehicle, such as maximum
`vehicle speed, in response to a vehicle limitation control
`signal. FIG. 1 illustrates an exemplary environment in which
`the described embodiment of the invention can be imple-
`mented. The environment 1 includes a command device 10
`
`configured to issue a vehicle limitation control signal indica-
`tive of a desire of a human operator of the command device
`to limit one or more performance characteristics of a vehicle
`14. The command device 10 can comprise many difierent
`known electronic devices, such as a personal computer, a
`personal digital assistant (PDA), a wireless phone, a pager,
`or a variety of other electronics capable of creating a control
`signal. The control signal is indicative of a desire to cause
`the vehicle 14 to enter a vehicle limitation mode, whereby
`its maximum speed (or other performance characteristic) is
`limited. The vehicle limitation control signal may preferably
`be generated remote from the vehicle 14 and communicated
`to the vehicle 14 over a wireless communication network 12.
`
`The wireless communication network 12 can comprise any
`one of a variety of known wireless communication networks
`that is capable of transmitting signals from a source device
`to a destination device in a wireless fashion. In addition to
`
`the features illustrated in FIG. 1, other components could be
`included in the environment 1 as well. For example, the
`command device 10 could be connected to a local area
`
`network (LAN) or wide area network (WAN), such as the
`Internet, and control signals issued by the command device
`10 could be transmitted first through such a LAN or WAN
`and then through the wireless communication network 12 to
`the vehicle 14. Other variations of this environment are also
`
`contemplated to be within the scope of the present invention.
`Though not illustrated in FIG. 1, it is contemplated that
`the vehicle limitation control signal that initiates the limited
`performance mode of the vehicle can also be generated
`locally from within the vehicle. For example, it is contem-
`plated that a local command device, such as a switch or
`button, could be installed inside of the vehicle so that a
`vehicle operator could initiate the limited performance mode
`on the vehicle. It is further contemplated that, depending on
`the particular embodiment of the invention,
`the limited
`performance mode could be activated by: (i) a remotely-
`issued control signal only (as illustrated in FIG. 1); (ii) a
`locally-issued control signal only (as described above); or
`(iii) either a remotely-issued control signal or a locally-
`issued control signal. A remotely-issued control signal can
`be initiated by, for example, a manager of a commercial fleet
`of vehicles, whereas a locally-issued control signal can be
`issued by the driver.
`When a particular embodiment of the invention includes
`the ability to remotely-issue the control signal, the vehicle
`14 is configured with a signal-receiving device mounted
`thereon, which is capable of receiving a wirelessly-trans-
`mitted control signal. The signal-receiving device will typi-
`cally include an antenna and receiver for receiving the
`control signal and, possibly, a means for storing, modifying,
`adjusting or otherwise causing the received control signal to
`be converted into a format that is usable by the system to
`limit one or more operational performance characteristics of
`the vehicle. Various signal-receiving devices are known to
`those of skill in the art. One example of a known signal-
`
`

`

`US 7,084,735 B2
`
`3
`fiom the
`commercially-available
`is
`receiving device
`assignee hereof under the trademark, PRISM.TM Other sig-
`nal-receiving devices can also be used in connection with
`the invention.
`
`FIG. 2 sets forth an illustrative signal-receiving device 16,
`which could be mounted to the vehicle 14. The signal-
`receiving device may receive the vehicle limitation control
`signal 18 (fi'om the remotely-located command device 10)
`via antenna 17. Though not shown in FIG. 2, the signal-
`receiving device may also (or alternatively) receive a vehicle
`limitation control signal from a command device locally-
`mounted to or in the vehicle 14 and operable by the driver
`of the vehicle. When the signal-receiving device 16 relays a
`vehicle limitation control signal (either from a remote or
`local command device), the signal-receiving device 16 pro-
`vides a vehicle limitation signal 20. The signal-receiving
`device 16 may be configured to modify or otherwise adjust
`the nature ofthe received control signal 18, when generating
`the vehicle limitation signal, into any useable format. Fur-
`ther,
`in the event that the embodiment of the invention
`includes a locally-mounted command device only (i.e., not
`configured to receive remotely-issued control signals), the
`locally-mounted command device may supply the vehicle
`limitation signal 20 directly. Further, a vehicle limitation
`signal 20 may be automatically activated for various other
`reasons, such as if the vehicle 14 loses communication with
`the command device 10.
`
`The signal-receiving device 16 provides the vehicle limi-
`tation control signal 20 to a control circuit or control module
`in order to limit one or more operational performance
`characteristics of the vehicle 14. Various systems and meth-
`ods can be used to limit operational performance character-
`istics of a vehicle. Exemplary systems and methods for
`limiting the maximum speed of a vehicle are described
`hereinafter.
`
`A first exemplary system and method for limiting the
`maximum speed of a vehicle in response to a vehicle
`limitation signal 20 is set forth in FIG. 3. This exemplary
`system and method is particularly applicable to vehicles,
`such as heavy-duty trucks, that incorporate an SAE Jl 922
`control link, defined by the Society ofAutomotive Engineers
`(SAE). Under this embodiment of the invention, the vehicle
`limitation control signal 20 is provided to a microprocessor
`unit (MPU) 22 (sometimes referred to herein as a “control-
`ler”). The vehicle limitation control signal 20 may be
`provided to the MPU 22 via a discrete input terminal 19 in
`the form of a binary electrical signal, i.e., either a “hi
`” or
`“low” state, one of which states indicating a desire to limit
`the maximum vehicle speed. Alternatively, the vehicle limi-
`tation signal 20 may be provided to the MPU 22 via an SAE
`J 1708 data bus 34, through an RS 285 interface 30 and a
`Universal Asynchronous Receiver/Transmitter
`(UART)
`device 26, in which case the vehicle limitation signal 20
`would conform to SAE J 1587 format. Other methods of
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`supplying a vehicle limitation signal to the MPU may also 55
`be used. Regardless of the manner in which the vehicle
`limitation signal 20 is provided to the MPU 22, the vehicle
`limitation signal 20 causes the MPU 22 to initiate a vehicle
`limitation mode by issuing commands to the vehicle’s
`Engine Control Module (ECM) over the SAE J1922 control
`link 32 via UART 24 and RS 485 interface 28.
`
`60
`
`The SAE J1922 control link standard defines a particular
`command code that can be issued over the J1 922 control link
`
`to limit the engine speed and torque rating of the vehicle
`(referred to hereinafier as the “speed limit command code”).
`The speed limit command code should be transmitted to the
`J1922 control link at least every 250 ms for as long as the
`
`65
`
`4
`
`vehicle limitation mode is engaged. Accordingly, under this
`embodiment of the invention, the MPU 22, in response to
`receiving an activated vehicle limitation control signal 20,
`causes a speed limit command code to be issued over the
`J 1922 control link at least every 250 ms while the vehicle
`limitation mode is engaged.
`FIG. 4 illustrates an embodiment of an algorithm that can
`be used to control the transmission of speed limit command
`codes to the J l 922 control link. Upon startup of the routine,
`a broadcast timer is started at block 402. Because the J1922
`
`standard recites that a speed limit command code be trans-
`mitted at least every 250 ms to maintain a maximum vehicle
`speed in place, the broadcast timer is preferably a 250 ms
`broadcast timer. At block 404, the broadcast timer is queried
`to determine if a timeout has occurred. The broadcast timer
`
`is continuously monitored to determine when a timeout has
`occurred. When a timeout occurs, the broadcast timer is reset
`and a J1 922 vehicle limitation flag is tested at block 406. The
`J 1922 vehicle limitation flag is preferably a binary indicator
`that stores whether or not the vehicle is in limitation mode.
`
`If the vehicle limitation flag is “1” (indicating that the MPU
`22 has received an active vehicle limitation signal 20), then
`the MPU 22 transmits a speed limit command code over the
`J 1922 control
`link (shown in block 410). If the vehicle
`limitation flag is “0” (indicating that the MPU has not
`received an active vehicle limitation signal 20), then the
`MPU 22 does not transmit a speed limit command code. In
`either event, the MPU 22 next queries the vehicle limitation
`signal 20, as shown in blocks 412 and 414. If the vehicle
`limitation signal 20 indicates that the vehicle should be in a
`vehicle limitation mode, then the vehicle limitation flag is
`set to “l”, as shown in block 416. If the vehicle limitation
`control signal 20 does not indicate that the vehicle should be
`in a vehicle limitation mode, then the vehicle limitation flag
`is set to “0”, as shown in block 418. Then, control of the
`algorithm is looped back to block 404, where the broadcast
`timer is again continuously queried until a timeout occurs,
`and the routine is repeated. In this way, whenever the vehicle
`limitation flag is set (resulting from the receipt of an active
`vehicle limitation control signal 20, either over the input line
`19 or the J 1708 data bus 34), the MPU 22 transmits the
`speed limit command code over the J1922 control link to the
`ECM once every 250 ms, which limits the maximum speed
`of the vehicle. Preferably, the above-described routine is
`implemented in software or hardware in the MPU 22.
`FIG. 5 illustrates a second exemplary embodiment of a
`system and method that can be used for limiting the maxi-
`mum speed of a vehicle in response to a vehicle limitation
`control signal 20. Components in FIG. 5 that are the same as
`those in FIG. 3 bear the same reference numerals. As in the
`
`first exemplary embodiment, the vehicle limitation control
`signal 20 can be provided to the MPU 22 either through a
`discrete signal input 19 or across the J 1708 data bus 34. In
`response to receiving a vehicle limitation control signal 20
`indicative of a desire to limit the performance characteristics
`of the vehicle 14,
`the MPU 22 limits the output of the
`vehicle’s electronic throttle pedal (not shown), which is
`provided to the vehicle’s ECM. The present embodiment
`assumes that
`the vehicle employs one of two possible
`electronic throttles that are known in the art: (i) a resistive
`throttle; or (ii) a pulse-width modulated throttle. As one
`skilled in the art will understand, a resistive throttle gener-
`ally involves adjusting a variable resistance between a
`constant application voltage in response to an operator
`command, such as an adjustment of an accelerator pedal.
`The voltage drop across the variable resistance determines
`the throttle output and thus the vehicle speed. As one skilled
`
`

`

`US 7,084,735 B2
`
`5
`in the art will further understand, a pulse-width modulated
`throttle is configured to produce a pulse-Width modulated
`signal (i.e., a “pulse train”) to the vehicle’s ECM, wherein
`the width and frequency of the pulses are indicative of the
`desired vehicle speed.
`J1(A&B),
`sets of jumpers
`four
`FIG. 5 illustrates
`J2(A&B), J3(A&B), and J4(A&B), which allow a single
`physical implementation of this embodiment of the inven-
`tion to be used with a wide variety of vehicles, regardless of
`whether they have a resistive throttle or a pulse-width
`modulated throttle. If the vehicle uses a resistive throttle,
`then jumpers JlA, J2A, BA, and J4A are connected, and if
`the vehicle uses a pulse-width modulated throttle,
`then
`jumpers J1B, J2B, BB, and MB are connected. It is also
`within the scope of this invention to implement a physical
`embodiment that can be used with either a resistive throttle
`
`or a pulse-width modulated throttle, but not both, in which
`case jumpers J1, J2, J3, and J4 could be eliminated. For
`purposes of description, it is first assumed that the presently-
`described embodiment of the invention is installed on a
`
`vehicle that uses a resistive throttle, and that, accordingly,
`jumpers JlA, J2A, BA, and J4A are connected. During
`normal operation, relay CRlA is in the “B” position and
`CRIB is in the “A” position. The normal position of relay
`CRlA allows the vehicle’s Engine Control Module (ECM)
`to provide a constant voltage 07+) through jumper J1A over
`line 42 to the vehicle’s throttle pedal (not shown). Usually,
`the constant voltage is nominally 5 volts. Further, the normal
`position of relay CRIB allows the ECM to respond to the
`driver’s engagement of the vehicle’s cruise control on/ofi
`switch. In response to movement of the vehicle’s accelerator
`pedal (not shown), the variable resistance of the throttle
`position sensor coupled between the V+ voltage and ground
`is adjusted, which, in turn, adjusts the voltage drop across
`the variable resistance. The voltage drop across the variable
`resistance controls the output of the throttle position sensor,
`which is provided over line 44 through jumper J2A to the
`vehicle’s ECM. The ECM uses the throttle position sensor
`output to control the vehicle’s RPM level and thus the
`vehicle speed.
`When the vehicle limitation control signal 20 is activated
`(or an appropriate signal is received over the J1708 data
`bus), the MPU 22 establishes a V+ output on the D/A
`converter 40 identical to that supplied from the ECM. The
`MPU 22 activates relay CR1 (A&B) such that CRlA moves
`from position “B” to position “A” and CRlB moves from
`position “A” to position “B”. The activation of relay CR1
`simultaneously disengages the vehicle’s cruise control
`enable switch and switches the input to the throttle position
`sensor (not shown) over line 42 from the constant V+
`supplied by the ECM to the V+ output on the D/A converter
`40. Then, the MPU 22 gradually decreases the V+ voltage of
`the D/A converter 40 to a lower voltage corresponding to the
`maximum engine RPM allowed to produce the desired
`maximum speed of the vehicle. As the voltage from the D/A
`converter 40 is reduced, so is the maximum output from the
`throttle position sensor supplied to the vehicle’s ECM over
`line 44. Generally, a 1.2 volt output from the D/A converter
`40 will impose a limit of 1200 RPM on the engine. As long
`as the reference voltage supplied to the throttle position
`sensor is limited, the maximum speed of the vehicle will be
`limited because the maximum output fi'om the throttle
`position sensor (supplied to the ECM) directly corresponds
`to the reference voltage supplied to the throttle position
`sensor. Though the maximum speed ofthe vehicle is limited,
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`it is still possible for the driver to completely control the
`speed of the vehicle in a normal fashion at any level up to
`the limited speed.
`Now, it is assumed that the presently-described embodi-
`ment of the invention is installed on a vehicle having a
`pulse-width modulated throttle. Accordingly, jumpers JlB,
`J2B, BB, and MB are connected. During normal operation,
`relay CR2 is deactivated such that CR2A is in the “A”
`position and CR2B is in the “B” position. As a result, the
`throttle position sensor can provide a train of pulses (some-
`times referred to herein as the “primary pulse train”) over
`line 44 through jumper J2B to the vehicle’s ECM. Normally,
`the width of the pulses is determined solely by the position
`of the vehicle’s accelerator pedal. Further, if requested by
`the vehicle operator, the ECM can issue a signal through MB
`and line 46 to the vehicle’s cruise control switch to turn the
`
`vehicle’s cruise control function on, if desired by the driver.
`When the MPU 22 receives a vehicle limitation signal 20
`(or appropriate J 1708 message), the MPU 22 sets the PWM
`output line 50 “high” and then activates relay CR2, which
`causes CR2A to move to position “B” and CR2B to move to
`position “A”. The activation of CR2A causes the ECM to
`receive its throttle input on line 52 through the “AND” gate
`54. The activation of CR2B disengages the cruise control
`engage switch. At this point, with the signal on line 50 being
`held “high”, the pulse train from the throttle position sensor
`is allowed to simply pass through to the ECM. To limit the
`vehicle’s RPM and speed, the MPU 22 samples the pulse
`train from the throttle position sensor on its PWM sense
`input line 48, and, using an internal timer, establishes a
`matching pulse train, having an identical duty cycle and
`pulse width. The matching pulse train is supplied by the
`MPU 22 on the PWM output line 50 to the “AND” gate 54
`(sometimes referred to herein as the “secondary pulse
`train”). Again, while the pulse train supplied by the vehicle’s
`throttle position sensor and the pulse train supplied by the
`MPU mirror each other, the input to the ECM over line 52
`will be the same as the pulse train generated by the throttle
`position sensor, thus making the vehicle appear to operate
`normally to the driver. To limit the vehicle’s speed, the MPU
`22 gradually reduces the width of the pulses that it generates
`on the PWM output line 50 and provides to the “AND” gate
`54. Since the output of the “AND” gate is “high” only when
`both inputs are “high”, the shorter pulses generated by the
`MPU will limit the width of the pulses supplied to the ECM
`on line 52 (sometimes referred to herein as a “limited pulse
`train”). The MPU gradually decreases the width of the
`pulses output on line 50 to a level that corresponds to the
`maximum desired vehicle RPM. As long as relay CR2A is
`in position “B” and the width of the pulses supplied by the
`MPU 22 is limited, the maximum speed of the vehicle will
`be limited.
`
`FIG. 6 illustrates an exemplary primary pulse train sup-
`plied by the vehicle’s throttle position sensor and a corre-
`sponding secondary pulse train supplied by the MPU 22. A
`third pulse train is also depicted in FIG. 6, which illustrates
`an exemplary output pulse train from the AND gate 54. The
`first portion (from left to right) of FIG. 6 illustrates a time
`when the vehicle limitation mode is first engaged and the
`PWM output line 50 is set to “high” such that the primary
`pulse train remains in control of the throttle input signal to
`the vehicle’s ECM. The middle portion of FIG. 6 illustrates
`a time when the MPU 22 creates a secondary pulse train on
`the PWM output line 50 that mirrors the primary pulse train.
`The third portion of FIG. 6 illustrates a time when the MPU
`22 reduces the width of the pulses making up the secondary
`
`

`

`US 7,084,735 B2
`
`7
`pulse train such that the secondary pulse train controls the
`throttle input signal (output of the AND gate 54) to the
`vehicle’s ECM.
`
`FIGS. 7—9 set forth flowcharts of exemplary algorithms
`that can be employed by the MPU 22 to implement the
`above-described embodiment of the invention. FIG. 7 illus-
`
`trates an exemplary mainline algorithm for controlling the
`MPU 22. The mainline algorithm begins at block 702. As
`shown in block 704, upon power-up, the MPU 22 performs
`any appropriate reset functions. At block 706, the MPU 22
`queries a non-volatile memory location to determine if a
`vehicle limitation disengage flag is set to “1”. The vehicle
`limitation disengage flag is stored in non-volatile memory so
`that the vehicle limitation mode cannot be reset merely by
`turning the vehicle off and restarting it. If the vehicle
`limitation disengage flag is set to “l”, the vehicle limitation
`mode is disengaged by clearing the vehicle limitation flag
`and a disengage flag, shown at block 708. Next, shown at
`block 710, the MPU 22 reads the vehicle limitation signal
`line 19 and/or the 11708 data bus, depending upon the
`method used to supply the vehicle limitation signal 20 to the
`MPU 22. Then the MPU 22 determines if a vehicle limita-
`
`tion control signal 20 has been provided, as shown at block
`712. If so, at block 714 the MPU 22 determines if the vehicle
`limitation control signal is indicative of a disengage message
`or an engage message. If the message is indicative of an
`engage command, the MPU 22, at block 718, clears the
`vehicle limitation disengage flag, sets the vehicle limitation
`flag and performs the appropriate vehicle limitation function
`(as described in more detail hereinafter), depending upon
`whether the vehicle uses a resistive throttle position sensor
`or a pulse-width-modulated throttle position sensor. If the
`message is indicative of a disengage command, the MPU 22,
`at block 716, sets the vehicle limitation disengage flag.
`Regardless of the nature of the message, control of the
`algorithm is then transferred back to block 710, where the
`MPU 22 again queries the vehicle limitation signal line 19
`or the 11708 data bus 34, as the case may be.
`this
`As can be appreciated from reviewing FIG. 7,
`embodiment of the invention preferably allows the vehicle
`limitation mode be disengaged upon the MPU receiving a
`disengage signal over line 19 or the J1708 data bus and upon
`the vehicle being turned off and restarted. That is, once a
`vehicle limitation mode is engaged, it can only be disen-
`gaged after the vehicle has been turned off and restarted.
`This feature, though not necessary to accomplish the basic
`goal of limiting the performance of the vehicle,
`is an
`optional safety feature. When the vehicle is in vehicle
`limitation mode, it is probable that the driver will be holding
`the accelerator in its maximum position. If the vehicle
`limitation mode were to be abruptly disengaged while the
`driver was holding the accelerator in its maximum position,
`the driver could conceivably lose control the vehicle as a
`result of the abrupt change in speed of the vehicle. Accord-
`ingly, this particular embodiment of the invention requires
`that the vehicle be turned off and restarted before disengag-
`ing the vehicle limitation mode.
`FIG. 8 illustrates a flowchart of an exemplary algorithm
`that could be used to implement the vehicle limitation mode
`on a vehicle that uses a resistive throttle position sensor. The
`algorithm shown in FIG. 8 would be called fi'om block 718
`of FIG. 7. The resistive vehicle limitation algorithm begins
`at block 802. At block 804, the MPU 22 sets the output of
`the D/A 40 to V+ volts to match the V+ volts normally
`provided to the variable resistance of the throttle position
`sensor by the ECM. As indicated above, V+ is typically a
`nominal 5 volts. At block 806, the MPU 22 energizes relay
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`CR1, which, as described above, disengages the vehicle’s
`cruise control and connects the throttle pedal to the output of
`the D/A converter 40 instead of the V+reference voltage
`provided from the ECM. Then, at block 808, the MPU 22
`gradually reduces the output of the D/A converter 40 to a
`level corresponding to a desired maximum engine RPM.
`Then, at block 810, control
`is returned to the mainline
`algorithm illustrated in FIG. 7.
`FIG. 9 illustrates an exemplary algorithm that could be
`used to implement the vehicle limitation mode on a vehicle
`that uses a pulse-width-modulated throttle position sensor.
`As above, the algorithm set forth in FIG. 9 would be called
`from