[19]
`United States Patent
`[45]
`Date of Patent:
`Sep. 15, 1992
`Krampe et a1.
`
`[11]
`
`Patent Number:
`
`5,146,892
`
`||||l|||l|||||lllllllllllllIlllllllllllll|||||||||||l||||l||||l|||Illllllll
`U3005146392A
`
`[54]
`
`METHOD AND ARRANGEMENT FOR THE
`OPEN-LOOP AND/OR CLOSED-LOOP
`CONTROL OF THE ENGINE POWER OF AN
`INTERNAL COMBUSTION ENGINE OF A
`MOTOR VEHICLE
`
`[751
`
`Inventors: Wolfgang Krampe, Seoul, Rep. of
`Korea; Bernd Liebemth-Ieden,
`Leouberg, Fed. Rep. of Germany
`
`4.969.431 llx’l990 Wataya ...............................
`
`l23f399
`
`FOREIGN PATENT DOCUMENTS
`
`3621937
`3808382
`
`1/1983 Fed. Rep. of Germany ,
`9/1939 Fed. Rep. of Germany .
`OTHER PUBLICATIONS
`
`Patent Abstracts of Japan, 009-209 (M407), Aug. 27,
`1985.
`.
`
`['13] Assignee:
`
`Robert Bosch Gth, Stuttgart. Fed.
`Rep. of Germany
`
`Primary Examiner—Tony M. Argenhright
`Attorney. Agent. or Firm—Walter Ottesen
`
`[21]
`
`[22]
`
`App]. No.: 671,858
`
`Filed:
`
`Apr. 4, 1991
`
`Foreign Application Priority Data
`[30]
`Aug. 4. 1989 [DE]
`Fed. Rep. of Germany ....... 3925831
`
`{51]
`Int. CU ....................... F02D 11/10; F02D 41/22
`
`
`[52]
`1.1.5. Cl.
`123/399; 123/193 D
`[58] Field of Search .................... 123/399, 479, 193 D
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`
`4,305,359 12/198] Mann et a1.
`...... 128/333
`
`4,601,199 7/1986 Den: ..............
`Til/118.1
`
`4,644,922
`2/1987 Gléickler et a1.
`123/493
`
`.......
`.. 123/198 D
`4.9055645
`3/1990 Bonse et al.
`4,960,087 10/ I990 Junginger et a}.
`............. 123/ 198 D
`
`ABSTRACT
`[57]
`A method and an arrangement for the Open-loop and/or
`closed-100p contra} of the engine power of an internal
`combustion engine of a motor vehicle is suggested. For
`checking a safety function. the arrangement intervenes
`in the fuel metering in the sense of reducing engine
`speed when an operating conditiou critical to safety is
`present. This safety function is triggered in the overrun
`operation of the internal combustion engine indepen-
`dently of the safety condition and the correct perfor-
`mance is checked. The safety function is detected as
`being defective when 2. unlimited metering of fuel takes
`place in this operating condition when the safety func-
`tion is triggered.
`
`14 Claims, 4 Drawing Sheets
`
`SUPPLY RE POSITION
`SIGNAL T0 ENGINE
`CONTROL UNIT 22
`
`
`
`
`
`HAS PREGIVEN TIHE
`DURATION EUPSED ?
`
`
`
`REQUEST
`
`IS ENGINE SPEED
`GREATER TIM
`IIO
`A PREGIVEN
`
`ENGINE SPEED?
`I12
`
`IS FLEL
`
`“WING
`
`SWITCI-ED OFF '_?
`
`
`
`SAFETY FUMTION
`RECOGNIZED AS
`
`
`
`VW EX1014
`
`US. Patent No. 6,588,260
`
`VW EX1014
`U.S. Patent No. 6,588,260
`
`

`

`US. Patent
`
`Sep. 15, 1992
`
`Sheet 1 of 4
`
`5,146,892
`
`
`
`

`

`US. Patent
`
`Sep. 15, 1992
`
`Sheet 2 of 4
`
`5,146,892
`
`F l G. 2
`
`START
`
`
`Féosaf‘EfiEII'i-ééfis
`FLAP ASSUMED ITS
`IDLE POSITION?
`
`
`
`SUPPLY IDLE POSITION
`SIGNAL TO ENGINE
`CONTROL UNIT 22
`
`
`
`
`
`
`
`HAS PREGIVEN TIME
`DURATION ELAPSED?
`
`
`
`
`IS FUEL METERING
`
`SWITCHED OFF ?
`
`
`
`
` IS ENGINE SPEED
`
`
`WITHDRAW
`GREATER THAN
` [IO
`
`
`IDLE POSITION
`A PREGIVEN
`
`
`SIGNAL
`
`ENGINE SPEED ?
` IIZ
`
`
` IS FUEL
`METERING
`
`SWITCHED OFF ? N
`
` I24
`
`INTERRUPT
`TEST
`
`
`
`SAFETY FUNCTION
`
`
`
`RESET IDLE
`
`RECOGNIZED AS
`
`POSITION
`
`BEING
`
`SIGNAL
`DEFECTIVE
`
`
`
`
`W | THDRAW
`
`GENERATE
`SAFETY
`ALARM
`
`
`
`REOU EST
`SIGNAL
`
`
`
`END
`
`

`

`US. Patent
`
`Sep. 15, 1992
`
`Sheet 3 of 4
`
`5,146,892
`
`1
`
`FIG.3
`
`

`

`US. Patent
`
`Sep. 15, 1992
`
`Sheet 4 of 4
`
`5,146,892
`
`
`
`

`

`1
`
`5,146,892
`
`METHOD AND ARRANGEMENT FOR THE
`OPEN—LOOP AND/OR CLOSED-LOOP CONTROL
`OF THE ENGINE POWER OF AN INTERNAL
`COMBUSTION ENGINE OF A MOTOR VEHICLE
`
`FIELD OF THE INVENTION
`
`The invention relates to a method and an arrange-
`ment for the open—loop and/or closed-loop control of
`the engine power of an internal combustion engine of a
`motor vehicle. The desire of the driver is electronically
`transmitted to an engine power actuating element with
`a safety function becoming effective when there is an
`operating condition critical to safety in the area of the
`open-loop control and/or the closed-loop control by
`intervening in the metering of fuel in the sense of reduc-
`ing engine speed.
`BACKGROUND OF THE INVENTION
`
`One such method or arrangement is known from US.
`Pat. No. 4,305,359. There, an electronic accelerator
`pedal system is described, which recognizes an opera-
`tional condition of the system critical to safety by a
`comparison of the accelerator pedal position and the
`actuator position. when, for example. the actuator is in
`its gas position and the accelerator pedal is in the idle
`position. Such an operating condition can occur when
`the actuator is jammed. In accordance with U.S. Pat.
`No. 4,305,359, the engine speed or power of the engine
`is reduced when the safety condition 'is recognized in
`that an aggregate influencing the engine speed of the
`internal combustion engine is driven in the sense of a
`reduction of engine speed. In this connection, the sup-
`ply of fuel to the engine is interrupted. A disadvantage
`of this kind of procedure is that a failure of this safety
`function is not detectable and, in the safety situation for
`an open power actuator,
`the electronic accelerator
`pedal system can accelerate the vehicle uncontrolled
`notwithstanding active safety function.
`A method for controlling the internal combustion
`engine in overrun operation is known from U.S. Pat.
`No. 4,644,922 wherein, for detected overrun operation,
`the fuel supply is switched off above a limit engine
`speed which changes as a function of time. In this con-
`nection, the overrun operation is then present when the
`actuator or accelerator pedal is in the idle position.
`SUMMARY OF THE INVENTION
`
`The invention then has the object to undertake a
`check of the availability of this safety functioa for im-
`proving operating safety of a motor vehicle with a
`safety function of the shave-mentioned type. This ob—
`ject is realized in that during specific operating phases
`of the engine, the safety function is triggered indepen-
`dently of the safety situation and the correct execution
`of the safety function is checked.
`The solution according to the invention has the ad-
`vantage that the safety function can be continuously
`checked as to its trouble-free operation even during
`operation of the motor vehicle and a malfunction of the
`safety function can be detected in time so that a func-
`tioning safety function can be utilized in an actually
`occurring safety condition.
`A further advantage of the concept of the invention is
`seen in that the check of the safety function, that is the
`triggering of the safety function for test purposes in
`overrun operation ofthe engine. neither influences driv-
`
`2
`ability nor exhaust gas and therefore is not noticed by
`the driver.
`Further advantages become evident from the descrip-
`tion of the following embodiments in connection with
`the dependent claims.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`lo
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`The invention will be explained below with respect to
`the embodiments illustrated in the drawings. FIG. 1
`shows a block diagram of an engine control system
`selected because it provides a good overview; FIG. 2
`describes a flowchart for explaining the procedure of
`the invention while FIG. 3 shows a time diagram of the
`course of the signals occurring when carrying out the
`method of the invention and FIG. 4 describes advanta-
`geous further embodiments of the inventive concept.
`DESCRIPTION OF THE PREFERRED
`
`EMBODIMENTS OF THE INVENTION
`FIG. 1 shows an internal combustion engine 10 illus-
`trated symbolically having an intake pipe 12 in which a
`throttle flap 1% is disposed. In addition, the engine in-
`cludes an ignition arrangement 16 as well as at least one
`fuel-metering arrangement 18. Of course, the injection
`unit can be configured as a cylinder-specific injection as
`well as a central injection and the internal combustion
`engine can include a bypass bridging the throttle flap
`for controlling idle engine speed.
`An engine control system 20 is shown in phantOm
`outline in FIG. 1. This engine control system comprises
`essentially two units, an engine control unit 22 by means
`of which the engine parameters: fuel-metering, ignition
`and/or idle speed can be controlled as well as an elec-
`tronic engine power control 24 which is used for the
`coatrol of the throttle flap 14 in dependence upon the
`desire of the driver as well as for adjusting the idle
`engine speed.
`The engine control unit 22 is connected to measuring
`arrangements 30 to 32 of the engine and of the motor
`vehicle via input lines 26 to 28 for measuring operating
`characteristic data. These measuring arrangements, not
`shown completely in FIG. 1. transmit to the engine
`control unit 22 for example engine speed signals, mea-
`surement values for the air mass or air quantity, engine
`temperature, exhaust-gas composition and/or similar
`operating characteristic data known from the state of
`the art. The engine control unit 22 computes the quan-
`tity of fuel to be metered from these input variables
`and/or the suitable ignition time point and/or the posi-
`tion of the idle actuator. In FIG. 1, the engine control
`unit 22 is connected symbolically via its output lines 34
`and 36 to the driver stage 38 which controls via its
`connecting lines 40 to 42 the fuel-metering units 18
`corresponding to the computed fuel quantity to be me-
`tered as well as being connected via its output lines 44 to
`the ignition unit 16. The connecting lines 40 to 42 (or by
`the feedback lines 8|] to 82 described further below) it is
`intended to express that the inventive concept can find
`application with a central injection unit having one
`connecting line as well as for cylinder-specific injection
`units having two or more cylinders (and a correspond-
`ing line number); The engine control unit 22 is supplied
`with an idle speed signal 4-6 from the accelerator pedal
`or throttle flap and a safety actuating signal 48 via the
`connecting lines 46. 48 and 50 which connect the engine
`control unit 22 to the electronic engine power control
`24. The connecting line 50 symbolically represents an
`exchange of data between engine power centrol 24 and
`
`

`

`5,146,892
`
`l0
`
`IS
`
`20
`
`25
`
`35
`
`3
`engine control unit 22 which are necessary in the partic-
`ular unit for solving its task.
`The electronic engine power central system 24 is
`connected via its input lines 52 and 54 to 56 to measur-
`ing arrangements such as: one or more throttle flap
`potentiometers 58 for determining the throttle flap posi-
`tion; an arrangement 60 for measuring the road speed;
`and/or with an idle switch 62 of the throttle flap 14. In
`addition, the position of the accelerator pedal 66 is sup-
`plied via the input lines 68 to the electronic engine
`power control system 24 via one or more accelerator
`position potentiometers and a signal which represents
`the idle position of the accelerator pedal is supplied via
`the input line 70 to the electronic engine power control
`system 24. The electronic engine power control system
`24 influences via its output line 72 and its driver stage 74-
`the position ofthe actuator 76 in dependence upon these
`input signals. The actuator 16 is connected to the throt-
`tle flap 1‘ via connection 78 which is rigid so as to
`permit rotation of the throttle flap with the actuator.
`The connecting lines 40 to 42 for driving the fuel-meter-
`ing devices 18 are connected via feedback lines 80 to 82
`wherein measuring arrangements represented by diodes
`8‘ to 86 are disposed which detect the function or drive
`of the fuel-metering devices 18 and which supply this
`information via input lines 83 to 90 to the electronic
`engine power control 24. The electronic connection
`“accelerator pedal 66 ~ throttle flap 14” can have a
`mechanical connection superposed thereon as repre-
`sented by the dotted line in FIG. 1 which can take over
`an emergency operation when there is a fault of the
`electronic control.
`-
`The embodiment illustrated here in the context of an
`Otto engine does not limit the inventive concept to this
`engine type. For applications to diesel engines,
`the
`throttle flap is understood to mean the control rod con-
`trolling the quantity of fuel. In addition to the control
`function, the electronic engine power control system 24
`conducts a function check of its components and of
`itself pursuant to procedures known in the state of the to
`art. For example,
`in this way corresponding to the
`known state of the art, a defect for an Opened throttle
`flap and accelerator pedal in the idle position are de-
`tected. Further defect sources can include the potenti-
`ometer itself or the electronic equipment of the control
`system. The electronic engine power control system 24
`reacts to the detected defect by setting the safety re-
`quest signal 48 which is supplied to the engine control
`unit 22. The engine control unit 22 then switches off the
`fuel metering to the engine with highest priority with
`respect to its other control functions. Preferably, the
`fuel awitchoff takes place above a pregiven engine
`speed, typically Lilli) to 2,000 rpm; whereas, below this
`engine speed, fuel is supplied in order to make it possible
`to maintain an emergency Operation and keep the ancil-
`lary aggregates operational. Advantageously, and cape-
`cially for diesel engines, would be a reduction of the
`fuel metered to a pregiven emergency quantity in lieu of
`a switchoff.
`
`4
`resented by the diodes 84 to 86. Furthermore, in another
`advantageous embodiment, the course of the signals in
`the drive lines can be checked. If a defective safety
`function is determined during a check, the electronic
`engine power control 24 forms an alarm signal via its
`output line 73 to trigger a suitable defect reaction. This
`defect reaction is preferably realized in a mechanical
`emergency operation via the mechanical connection 92,
`in a power reduction by limiting the throttle-flap angle
`or in the warning lamp ’15 shown in FIG. 1 as exem-
`plary.
`Preferably, the check of the safety function is carried
`out during the overrun operation since, in this opera-
`tional phase, the engine control unit 22 carries out the
`overrun cutoff as known from the state of the art. In this
`way, negative influences on the driving performance or
`on the driver are precluded. The overrun operational
`phase is detected by the engine control unit by means of
`an idle position signal applied via the connecting line 46,
`that is an accelerator pedal or throttle flap in the idle
`position, a speed condition n>n0 and possibly in depen-
`dence upon further operating parameters of the engine
`such as engine temperature. If the safety request takes
`place during the overrun phase, then a precise assign-
`ment of the fuel cutoff to the idle positiOn signal or to
`the safety request signal is carried out in order that a
`precise monitoring of the safety function referred to
`above is ensured. This procedure is illustrated with
`respect to the flowchart of FIG. 2 to facilitate under-
`standing.
`After the start of the program part shown in FIG. 2
`and carried out in the engine power control 24, a check
`is made in inquiry block 100 as to whether the accelera—
`tor pedal or throttle flap has assumed its idle position.
`The program part is terminated in response to a nega-
`tive answer whereas in the positive case. the idle posi-
`tion signal is supplied via the connecting line 46 to the
`engine control unit 22 (102). The reaction time 104 is
`essentially determined by the computation time of the
`engine control unit 22. After this pregiverl reaction time
`104 has run, a check is made in the inquiry block 106 as
`to whether the fuel metering is switched off. If an inter-
`rupted fuel metering is detected in block 106, then the
`safety request is set pursuant to block 106 and the idle
`position signal is withdrawn in the next function block
`110. After the renewed reaction time 112 has run. a
`check is again made as to whether or not the fuel meter-
`ing is switched off {inquiry block 114). The fuel switch-
`off determined with a functionally 'operational safety _
`function in inquiry block 114 is based on the safety
`request signal corresponding to the measures of blocks
`108 and 110. That is, in block 116, the determination can
`be made that the safety function is in order and the test
`can be successfully terminated in that the idle position
`signal is again set and the safety request is withdrawn
`(118). If fuel metering is determined in inquiry block
`11‘, then: the safety function is recognized in block 120
`as being defective; an alarm signal is generated in block
`121; and, the program part is likewise terminated.
`The data which form the basis of the decisions in
`inquiry blocks 106 and 114 are supplied to the electronic
`engine power control 24 via the wireDR connection
`described above and the input lines 88 to 90.
`After the idle position (blocks 102 to 104) has been
`detected, the determination can be made in the above-
`describcd inquiry block 106 as a second possibility that
`fuel is being metered. Accordingly. the inquiry is made
`in block 122 which is not perforce present but advanta-
`
`4s
`
`50
`
`SS
`
`A monitoring of this safety function during operation
`of the engine is then attained in that the electronic en-
`gine power control 24 sets the safety request signal 48
`for test purposes. The electronic engine power system
`can check the correct execution of the safety request via
`the connection 80 to 82. In this way, the end stage out-
`puts or the drive lines for the metering units 18 are
`connected to the inputs 88 to 90 of the electronic engine
`power control via a so-called Wire-0R connection rep-
`
`60
`
`65
`
`

`

`5,146,892
`
`6
`of information to the electronic engine power control
`24
`
`5
`geously present whether, since the last successful test, a
`pregiven time duration, for example 15 minutes. has
`passed. If this is not the case, then a closer investigation
`can be dispensed with and the test is discontinued in
`block 124 and the program part terminated. If this time
`duration since the last successful test is however ex-
`ceeded, then a check of the safety function is forced
`(notwithstanding the fact that the fuel has not been shut
`off) via the inquiry block 126, which compares the
`instantaneous engine speed to a pregiven engine speed
`(for example 2,000 rpm). However, the condition of the
`inquiry block 126 that the engine speed is greater than a
`pregiven threshold engine speed must be fulfilled. In the
`other case, the test corresponding to block 124 is inter-
`rupted and the program part terminated. The pregiven
`threshold engine speed of the inquiry block 126 corre-
`sponds to a lower safety engine speed threshold below
`which no fuel cutoff can take place or fuel cutoff can
`take place only under certain conditions in order to
`prevent an immediate standstill of the engine or to not
`substantially deteriorate the driving comfort.
`A further clarification of the procedure according to
`the invention is obtained from the time diagram shown
`in FIG. 3. FIG. 3a describes the time-dependent signal
`response of the idle position signal transmitted on the
`connecting line 46. FIG. 3b shows the signal response of
`the safety request signal transmitted on connecting line
`48 and FIG. 3c shows the performance of the fuel me-
`tering. In time direction, the time diagram is subdivided
`into six phases to improve understanding. Phase 1 is
`characterized by the occurrence of the idle position
`signal and the cutoff of the fuel metering after a pre-
`given reaction time above an engine speed threshold,
`the so-called cutoff engine speed threshold. This phase
`characterizes the start of the overrun operation.
`In
`phase 2, the electric engine power control 24 detects the
`completed cutoff via its inputs 88 to 90; whereas. the
`control 24 emits in phase 3 the signal "safety request" to
`the engine control unit in order to simulate an operating
`condition critical to safety. Finally, in phase 4, the idle
`position signal is withdrawn by the electronic engine
`power control 24 in order to check the safety function
`and a check is made as to whether the fuel continues to
`remain cut off because of the safety request signal. In
`phase 5, the idle speed signal of the electronic engine
`power control is set and after a reaction time has run,
`the safety request is withdrawn in phase 6. The fuel
`metering remains cut off because of the overrun switch
`function. The defective operation of the safety function
`is then detected when, in phase 4, a metering of the fuel
`takes place (phantom outline).
`The signal level of the time traces shown in FIG. 3 is
`formed by digital 0-1 signals.
`If the safety function does not trigger a fuel cutoff,
`but only a reduction, then a defective function is de—
`tected in phase 4 if the fuel metering takes place unre-
`strictedly. In this case, the test of the safety function is
`not limited to the overrun Operation.
`FIG. 4 illustrates further advantageous realization
`forms of the concept according to the invention. To
`expedite matters, a complete explanation is not pro-
`vided with respect to the individual elements discussed
`in FIG. 1 and having the same reference numerals in
`FIG. 4 and an explanation is also not provided with
`respect to the functions of the arrangement explained
`above. The explanations with respect to FIG. 4 are
`therefore limited to' the differences with respect to the
`embodiment of FIG. 1 which Only relate to the return
`
`The output line 34 is illustrated symbolically in FIG.
`1 and leads from the engine control unit 22 to the driver
`stage 38. The output line functions as a carrier of vari-
`ous information. For example, information with respect
`to the length of the necessary injection pulse flows over
`the line 34a; whereas, the line 34b conducts a cutoff or
`reset signal to the driver stage 38 by means of which a
`fuel cutoff is carried out.
`For monitoring the safety function illustrated above,
`it is also possible to utilize the data of the output line 34.
`A line 200 connects the lines 34 with the element 202 or
`(shown in phantom outline} with the engine control unit
`22. The line 200 transmits a signal when the engine
`control unit effects fuel cutoff.
`In addition, a line 204 is provided which connects the
`element 202 with the driver stage 38 which, alterna»
`tively,
`is connemed With the engine control unit 22.
`This line carries a fault signal which is formed pursuant
`to methods known from the state of the art and a fault
`conditiou of the driver stage 38 such as short circuits or
`fault functions of the valve controls are announced.
`In the engine control unit or the element 202, the lines
`200 and 204 or their signals are logically OR connected.
`The result of this COR-connection in the engine control
`unit 22 is applied via the data exchange line 50 to the
`electronic engine power control 24. By applying the
`element 202 for connecting the lines 200 and 204, the
`electronic engine control 24 is supplied with a signal
`corresponding to the logic-0R connection via the line
`206 connecting the two units (202 and 24}.
`If a safety request 48 is set by the electronic engine
`control corresponding to the method according to the
`invention, then the control can detect the availability of
`the safety function by means of the signals supplied to
`the control as explained above. If a signal is present on
`the line 206 (alternately 50) during the set safety re-
`quest, then this means that the fuel cutoff has not taken
`place or that the driver stage 38 has a fault. The elec-
`tronic engine power control 24 then detects therefrom
`that the safety function is not available and sets an alarm
`signal via its output line 73.
`An embodiment of the element 202 is described in the
`following. The lines 200 and 204 are led to element 202
`via two diodes 210 and 211 having cathodes connected
`together at a connecting point 212 at which a resistor
`213 is connected. The resistor 213 is connected at its
`other end to a resistor 214 which is connected to
`ground. In addition, the resistors 213 and 214 are con-
`nected with the base of a transistor 215 having an emit-
`ter connected to ground and having a collector con-
`nected to line 206 and connected via a further resistor
`216 to the operating voltage. When a signal is applied to
`line 200 or 204, one or both diodes 210 and 211 is ren-
`dered conductive whereby the transistor 215 is likewise
`conductive and a signal representing a fault condition
`appears on line 206. The element 202 thereby operates
`as a logic-0R gate.
`.
`We claim:
`l. A method for control of the engine power of an
`internal combustion engine of a motor vehicle wherein
`said control is at least one of open-loop control and
`closed-loop control, with the driver’s desire being elec-
`tronically transmitted to an engine power actuating
`element and with a safety function becoming effective
`when there is an operating condition critical to safety in
`the area of said control which intervenes on the meter-
`
`10
`
`15
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`
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`
`35
`
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`
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`
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`
`65
`
`

`

`5,146,892
`
`3
`defective operation is detected by means of an unlimited
`metering of fuel.
`10. The method of claim 6, wherein the fault reaction
`comprises a transition to mechanical control of the
`throttle flap with at least one of a reduction in power of
`the internal combustion engine and an actuation of a
`warning light.
`11. An arrangement for the control of the engine
`power of an internal combustion engine of a motor
`vehicle equipped with an electronic accelerator pedal
`system wherein said control is at least one of open—loop
`control and closed-loop control, the arrangement com-
`prising:
`a safety device for intervening in the fuel metering in
`the sense of reducing engine speed when a condi-
`tion critical to safety is detected;
`means for detecting such an operating condition criti-
`cal to safety;
`means for influencing the fuel metering;
`means for activating the safety arrangement during
`pregiven operating phases of the internal combus-
`tion engine independently of the operating condi-
`tion critical to safety; and,
`means for checking the function of the safety arrange-
`ment.
`
`12. The arrangement of claim 11. further comprising
`means for detecting an overrun operation and for deter-
`mining the fuel cut-off condition with the check of the
`safety arrangement taking place in the overrun opera-
`tion and when the fuel is cut off.
`13. The arrangement of claim ll, wherein the safety
`arrangement is defective when unlimited fuel is metered
`while the safety arrangement is activated.
`1‘. The arrangement of claim 11, wherein the elec-
`tronic accelerator pedal system is connected to the
`fuel-metering means by one of a wire-OR connection
`and logic-0R connection for checking the correct func-
`tion of the safety arrangement.
`I
`U
`i
`t
`I
`
`7
`ing of fuel in the sense of reducing engine speed. the
`method comprising the steps of:
`checking the safety function by triggering the safety
`function during a pregiven operational phase of the
`engine independently of an operating condition 5
`critical to safety; and,
`checking the correct performance of the safety func»
`tion.
`
`20
`
`2. The method of claim I, wherein the safety function
`is triggered independently of the operational condition to
`critical to safety in the overrun operational phase when
`there are fuel cut—off conditions.
`3. The method of claim 1, wherein the safety function
`is detected as being defective when fuel is metered
`when a safety function is triggered independently of the 15
`operating condition critical to safety.
`4. Method of claim 2. wherein fuel is cut off with a
`detected idle position of the accelerator pedal or engine
`power actuator element and with an engine speed
`which is above a pregiven engine speed threshold.
`5. The method of claim 1, wherein the safety function
`is triggered independently of the operational condition
`critical to safety when the idle position of the accelera-
`tor pedal or the throttle flap is detected and the fuel is
`cutoff.
`6. The method of claim I, further comprising the
`steps of: detecting an idle position; detecting the cut-off
`of the fuel metering;
`triggering the safety function;
`removing the idle position signal; detecting whether
`fuel cut-off take place as a consequence ofthe safety 30
`function; and. triggering a fault reaction when fuel me-
`tering takes place.
`7. The method of claim 1 wherein, after a pregiven
`time duration since the last successful test when fuel
`cut-off was present. the safety function is triggered 35
`when fuel is metered.
`B. The method of claim 1, wherein the safety function
`causes a cut-off of the fuel.
`9. The method of claim. 1, wherein the safety function
`causes a reduction of the metered fuel quantity and a 40
`
`25
`
`45
`
`55
`
`65
`
`

`

`
`
`UNlTED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`PATENTND.
`
`DATED
`
`:
`
`:
`
`5,146,392
`
`September 15, 1992
`
`INVENTOHSI:
`
`Wolfgang Krampe and Bernd Lieberoth—Leden
`
`ItiscenifiedIhaterrerappearsin[he aboueidentflied palentandthaisfld LenarsPatentishareby
`corrected as shavvn heluvv:
`
`In the title page,
`
`item [22], please delete:
`
`"Filed:
`
`Apr. 4, 1991" and substitute:
`
`—— PCT filed:
`
`July 7, 1990 -- therefor.
`
`In the title page,
`
`item [86], please insert:
`
`—— [86]
`
`PCT No.:
`
`PCT/DE 90/00506
`
`§ 371 Date:
`
`April 4, 1991
`
`§ 102(e} Date: April 4, 1991 ~—.
`
`line 30: delete ”take" and substitute
`In column 7,
`—— takes —- therefor.
`
`Sgguxiandfkfiflediifis
`
`Fifth Day of October, 1993
`
`Commissioner of Fawn” and Trademarks Arresting Ofiicer
`
`
`
`BRL‘CE LEHMAN
`
`
`
`