GB2251075A - Device for the quasi-potential-free detection of signals in motor vehicles - Google Patents

Device for the quasi-potential-free detection of signals in motor vehicles Download PDF

Info

Publication number
GB2251075A
GB2251075A GB9124459A GB9124459A GB2251075A GB 2251075 A GB2251075 A GB 2251075A GB 9124459 A GB9124459 A GB 9124459A GB 9124459 A GB9124459 A GB 9124459A GB 2251075 A GB2251075 A GB 2251075A
Authority
GB
United Kingdom
Prior art keywords
voltage
operational amplifiers
operational amplifier
signals
potentiometer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9124459A
Other versions
GB2251075B (en
GB9124459D0 (en
Inventor
Wolfgang Bullmer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of GB9124459D0 publication Critical patent/GB9124459D0/en
Publication of GB2251075A publication Critical patent/GB2251075A/en
Application granted granted Critical
Publication of GB2251075B publication Critical patent/GB2251075B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
    • B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
    • B60R16/03—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/16—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance
    • G01D5/165—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance by relative movement of a point of contact or actuation and a resistive track

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Amplifiers (AREA)
  • Control Of Direct Current Motors (AREA)
  • Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)

Description

c 2251075 1 - Device for the quasi-potential-free detection of signals in
motor vehicles
Prior art
The invention relates to a device for the quasipotential-free detection of signals in motor vehicles, in particular for detecting the slider signal of an externally-supplied potentiometer, independently of the earthing differential which occurs constantly in motor vehicles.
It is generally customary to use potentiometers in motor vehicles in order to determine different operating parameters. For example, the position of the throttle valve, which is a measure of the loading of the internal combustion engine, is determined with the aid of a throttle valve potentiometer. The throttle valve potentiometer thus constitutes a mechanically changeable resistor at whose slider the signal voltage dependent on the position of the throttle valve is tapped off.
Usually, the throttle valve potentiometer is connected by one terminal to the vehicle electrical system voltage by means of a variable resistor and the other terminal of the potentiometer is connected to earth. The slider voltage to be evaluated occurs between the slider output and earth. A device for measuring the throttle valve position which describes an arrangement of this kind is known for example from DE-OS 37 14 697.
In the known potentiometer arrangements or the associated evaluation circuit arrangement it is not taken into account that when operating a motor vehicle a considerable earthing differential can occur which leads to the possibility of undesired errors occurring during the evaluation of the slider voltage.
4 Advantages of the invention is R. 23947 The device according to the invention has the advantage that by generating a prescribed voltage a common potential is generated wb-ich makes possible an evaluation of the slider voltage independently of the earthing differential.
It is particularly advantageous that with the evaluation circuit this prescribed voltage and the earthing differential are eliminated again, as a result of which the supply voltage for the potentiometer and the slider voltage are obtained at the output of the circuit arrangement in each case referred to the control device earth.
Advantageous developments and improvements of the device according to the invention are disclosed in the subclaims.
Drawing The single figure shows a circuit arrangement according to the invention for the quas i-potential- free detection of signals, for example the slider signal of a throttle valve potentiometer.
Description of the exemplary embodiment
The circuit arrangement illustrated in the figure has a voltage divider with the resistors R1 and R2, which voltage divider is connected between plus 5 volts and earth. The connecting point between the two resistors R1 and R2 is connected to the non-inverting input of an operational amplifier OP1, the operational amplifier OP1 being connected as a voltage follower, its output therefore being connected directly to the inverting input.
The voltage is supplied to the operational amplifier OP1 via a resistor R3 on whose other side the vehicle battery voltage UB is applied. Between the terminal of the resistor R3 and the operational amplifier R. 23947 OP1 and earth there is a Zener diode Dl connected in the blocking direction and parallel to the Zener diode DI there is a capacitor C1.
The output of the operational amplifier OPI is connected to the noninverting inputs of three further operational amplifiers OP2, OP3 and OP4, the inverting input of the operational amplifier OP2 is located via a resistor R5 on the slider S of the potentiometer P1, a further Zener diode D3 connected in the blocking direction being located between the inverting input of the operational amplifier OP1 and earth.
The inverting input of the operational amplifier OP3 is connected via a resistor R6 to the one side of the potentiometer Pl, the inverting input of the operational amplifier OP4 is connected via a further resistor R8 to the other side of the potentiometer Pl and is connected to earth via a Zener diode D2 operated in the blocking direction.
The resistors R5, R7 and R9 are located between the outputs of the operational amplifiers OP2, OP3, OP4 and the corresponding inverting inputs. Capacitors C2, C3 and C4 are located between the inverting inputs and the non-inverting inputs of the aforesaid operational amplifiers.
Two further operational amplifiers adjoin the operational amplifier OP2 and the operational amplifier OP4 in such a way that the output of the operational amplifier OP2 is connected via a resistor RIO to the inverting input of the operational amplifier OP5 and the output of the operational amplifier OP4 with its resistor R14 is connected to the inverting input of the operational amplifier OP6. The two non-inverting inputs of the operational amplifiers OP5 and OP6 are connected on the one hand to one another and on the other hand are connected via a resistor R12 to the output of the operational amplifier OP3, a resistor R13 being located between the common connecting point of the operational amplifiers OP5 and OP6 and earth.
For the purpose of feedback, in each case one is R. 23947 resistor R11 and R15 is located between the outputs of the operational amplifier OP5 and OP6 and the corresponding inverting inputs. The outputs of the operational amplifiers OP5 and OP6 are connected via resistors R17 and R16, respectively to one or more analog-to-digital converters ADW and thus to the control device ST.
The operational amplifier OP6 is also connected via the resistor R3 to the battery voltage UB and, in addition, to earth.
The mode of operation of the described circuit arrangement can be explained as follows:
With the circuit illustrated in the figure, the supply voltage UR and the slider voltage US of a potentiometer P1 not supplied with voltage from its own control device can be detected independently of the earthing differential UM between control device earth and potentiometer earth. Since when using the circuit arrangement in a motor vehicle the voltage is to be supplied to the operational amplifiers OP1 to OP6 by means of the motor vehicle battery voltage or the vehicle electrical system voltage UB, it is provided for a prescribed voltage LTV to be generated as a quasi-potential.
The voltage supply of the operational amplifiers with a battery or vehicle electrical system voltage UB is neceessary in order to prevent the operational amplifiers OP1 to OP6 limiting the measured values. This would not be -ensured if the aforesaid operational amplif iers were connected to a +5 volt voltage.
The prescribed voltage UV present at the output of the operational amplifier OP1 is set by means of appropriate selection of the resistors R1 and R2 in such a way that double the prescribed voltage UV is greater than or equal to a sum of the voltage to be detected and earthing differential UM, the voltages to be detected being the supply voltage for the potentiometer UR or the slider voltage US.
The prescribed voltage UV is generated at the output of the operational amplifier OP1 with the voltage divider Rl, R2 and the subsequent operational amplifier is R. 23947 OP1 connected as a voltage follower. The level of this prescribed voltage can be determined by the values of the resistors R1 and R2. The prescribed voltage UV is also present at the non-inverting inputs of the operational amplifiers OP2 to OP4 which, like the operational amplifiers OP5 and OP6, are connected as subtractors.
The measured signals, that is to say the supply voltage UR for the potentiometer Pl, the earthing differential UM and the slider voltage US are fed to the inverting inputs of the operational amplifiers OP4, OP3 and OP2 and subtracted there from double the prescribed voltage 2UV present in each case at the non-inverting input.
The minimum admissible operating voltage at which the circuit is still functional can be determined from double the prescribed voltage 2UV and the maximum occurring negative voltage differential. As long as the vehicle electrical system voltage or the battery voltage does not drop below this minimum admissible operating voltage, a correct functioning of the circuit arrangement is accordingly ensured.
With the operational amplifiers OP5 and OP6 the prescribed voltage UV and the earthing differential UM is (sic) eliminated so that the slider voltage is present at the output of the operational amplifier OP5 and the supply voltage for the potentiometer at the output of the operational amplifier OP6 referred to control device earth and is thus quasipotential-free.
Since the circuit arrangement permits a highimpedance wiring of the operational amplifiers, a detection of voltage values, for example of the slider voltage US, is possible up to a minimum of 5 millivolts without an additional negative voltage supply being requiredi' The circuit is therefore particularly suitable for use in motor-vehicles.
A smoothing of the operational amplifier supply voltage is achieved by means of the resistor R3, the Zener diode Dl and the capacitor Cl, they also serve as suppressor circuitry.
R. 23947 The Zener diodes D2 and D3 and the capacitors C2, C3, C4 which are located in each case between the inverting and the non-inverting input of the operational amplifier OP2, OP3 and OP4 are provided as suppressor circuitry against overvoltages and high-frequency interference.
if the circuit arrangement described hitherto is connected via one or more analog-to-digital converters ADW to the control device ST of a motor vehicle, a damping of the oscillation tendency can be obtained with the aid of the resistors R16 and R17.
- 7

Claims (11)

  1. Claims is 1. Device for the detection of signals in motor vehicles,
    preferably of the supply voltage and/or the slider voltage of a potentiometer not supplied by the control device, characterised in'that in addition to the signals (UR, US) the earthing differential (UM) is detected, and in that a prescribed voltage (UV) is generated which is related to the signals (UR, US) to be detected and the earthing differential (UM), and a further reference to the voltages thus obtained occurs so that the supply voltage (UR) and the slider voltage (US) are referred to control device earth in a quasi-poten tial-free manner.
  2. 2. Device according to Claim 1, characterised in that the prescribed voltage (UV) is at least twice as high as the sum of the voltages from one of the signals (UR, US) to be detected and the maximum earthing differential (UM) to be expected.
  3. 3. Device according to Claim 1 or 2, characterised in- that the potentiometer (Pl) is a throttle valve potentiometer for determining the throttle valve position or a potentiometer of an air flow meter.
  4. 4. Device according to Claim 1,, characterised in that the prescribed voltage (UV) is generated with an operational amplifier (OP1) supplied by the vehicle electrical system voltage (UB), in that the prescribed voltage (UV) is fed to three operational amplifiers (OP2, OP3, OP4), in each case the slider voltage (US), the earthing differential (UM) or the supply voltage (UR) being fed in addition to one of these operational amplifiers and the output signals of the operational amplifiers (OP2, OP3, OP4) being fed to two further is R. 23947 operational amplifiers (OP5, OP6) in such a way that in each case the non- inverting inputs of the operational amplifiers (OPS, OP6) are connected to the output of the operational amplifier (OP3).
  5. 5. Device according to Claim 4, characterised in that the operational amplifiers (OP2 to OP6) are switched as subtractors.
  6. 6. Device according to one of Claims 4 or 5, characterised in that the outputs of the operational amplifiers (OP5, OP6) are connected via resistors (R16, R17) and an analog-to-digital converter (ADW) to a control device (ST).
  7. 7. Device according to one of Claims 4 to 6, characterised in that Zener diodes (D2, D3) located in the blocking direction are connected between the inverting input of the operational amplifiers (OP2 or OP4) and earth.
  8. 8. Device according to one of the preceding Claims 4 to 7, characterised in that protective capacitors (C2, C3, C4) are connected between the inputs of the operational amplifiers (OP2, OP3, OP4).
  9. 9. Device according to one of the preceding claims, characterised in that the vehicle electrical system voltage (UB) is fed via a resistor (R3) to the operational amplifier (OP1), and a Zener diode (D1) and a capacitor (Cl) are connected between the terminal of the resistor (A3) facing the operational amplifier (OP1) and earth.
  10. 10. Device according to one of Claims 4 to 9, characterised in that a voltage divider (R1, R2) connected between a positive DC voltage of preferably 5 volts and earth is connected to the non-inverting input of the operational amplifier (OP1) and is provided for the purpose of setting the prescribed voltage (UV).
  11. 11. A signal detection device substantially as herein described with reference to the accompanying drawing.
GB9124459A 1990-11-20 1991-11-18 Device for the quasi-potential-free detection of signals in motor vehicles Expired - Fee Related GB2251075B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19904036941 DE4036941A1 (en) 1990-11-20 1990-11-20 DEVICE FOR QUASI POTENTIAL-FREE DETECTION OF SIGNALS IN MOTOR VEHICLES

Publications (3)

Publication Number Publication Date
GB9124459D0 GB9124459D0 (en) 1992-01-08
GB2251075A true GB2251075A (en) 1992-06-24
GB2251075B GB2251075B (en) 1994-10-19

Family

ID=6418613

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9124459A Expired - Fee Related GB2251075B (en) 1990-11-20 1991-11-18 Device for the quasi-potential-free detection of signals in motor vehicles

Country Status (4)

Country Link
JP (1) JPH04298669A (en)
DE (1) DE4036941A1 (en)
FR (1) FR2669737B1 (en)
GB (1) GB2251075B (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4803420A (en) * 1986-10-07 1989-02-07 U.S. Philips Corp. Method of determining the position of the tap on a resistance teletransmitter
GB2241337A (en) * 1990-02-24 1991-08-28 Ferranti Int Plc Potentiometric circuit arrangement for sensing wiper position.

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4177770A (en) * 1978-09-07 1979-12-11 Ford Motor Company Compensation of sensor voltage for reference potential variation
DE3632036A1 (en) * 1985-09-28 1987-04-02 Volkswagen Ag Device for adjusting the fuel-air mixture in an internal combustion engine with a lambda probe
JPH0781891B2 (en) * 1985-10-16 1995-09-06 株式会社日立製作所 Signal processing method of intake air flow rate measuring device for internal combustion engine
JP2765881B2 (en) * 1988-11-09 1998-06-18 三菱電機株式会社 Intake air amount measurement device for internal combustion engine

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4803420A (en) * 1986-10-07 1989-02-07 U.S. Philips Corp. Method of determining the position of the tap on a resistance teletransmitter
GB2241337A (en) * 1990-02-24 1991-08-28 Ferranti Int Plc Potentiometric circuit arrangement for sensing wiper position.

Also Published As

Publication number Publication date
GB2251075B (en) 1994-10-19
JPH04298669A (en) 1992-10-22
DE4036941A1 (en) 1992-05-21
FR2669737B1 (en) 1996-05-24
FR2669737A1 (en) 1992-05-29
GB9124459D0 (en) 1992-01-08

Similar Documents

Publication Publication Date Title
US8330528B2 (en) Active sensor with operating mode changeover
US5519397A (en) Circuit for processing the output signal from a resistive analog sensor, in particular for the fuel gauge of a motor vehicle, and systems fitted therewith
US4825148A (en) Resistance measurement circuit and method
EP0916928A1 (en) Rotational speed sensor
EP0503855A1 (en) Apparatus for failure identification for use in vehicle occupant protecting system
JPH1173226A (en) Control circuit generating control signal proportional to position of input device
GB2251075A (en) Device for the quasi-potential-free detection of signals in motor vehicles
US4945336A (en) Trouble detection apparatus for automobile air-bag system
US6647958B2 (en) Throttle control apparatus for internal combustion engine
US5335565A (en) Electronic control type automatic speed changer
US5167152A (en) Input processing circuit for air flow sensor
JP2568813Y2 (en) Ignition device for internal combustion engine
US4541271A (en) Measuring arrangement for continuous monitoring operating parameters of an internal combustion engine
EP0440979B1 (en) Wide angle gauge driver with resistive sensor
US6501261B2 (en) Evaluation circuit for a magnetoresistive sensor
US4541389A (en) Current regulator for an electromagnetic load utilized in conjunction with an internal combustion engine
JPH0826909B2 (en) Vehicle electromagnetic clutch temperature detection device
US5416665A (en) Vehicle electromagnetic clutch control device
US6580277B1 (en) Device for the ratiometric measurement of sensor signals
US5460028A (en) Circuit arrangement for conditioning the signal of a measuring sensor
KR100442895B1 (en) Measurement resistance temperature control device and temperature control method for detection of charge amount of distribution medium
US4601197A (en) Peak combustion pressure timing detector for internal combustion engine
US20040252437A1 (en) Device protecting an electronic circuit
US6844734B2 (en) Current detection circuit for A/F sensor
KR102141583B1 (en) Electronic exhaust gas reduction device for vehicle

Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19981118