DE102005025871A1 - Inductive or ohmic load e.g. electromagnetically operated actuator, controlling and monitoring circuit for use in e.g. direct injection diesel engine, has voltage measuring device measuring battery-sided voltage of inductive or ohmic load - Google Patents

Abstract

The circuit has a voltage measuring device (UAB2) for measuring a ground-sided voltage of an inductive or ohmic load (IL). A voltage measuring device (UAB1) measures a battery-sided voltage of the load. A supply of the load is controlled in case of an error in a safe operating condition. A low-side switch (LSS) and a high-side switch (HSS) e.g. MOSFET, are switched independent of each other by a control device. Independent claims are also included for the following: (1) a method of controlling and monitoring an inductive or ohmic load (2) a control device for an internal combustion engine.

Description

State of technology

The The present invention relates to a circuit and a method for monitoring and controlling a load, in particular an inductive or ohmic Load.

electrical Loads are usually over switches connected to a power supply. The switch can with respect to the Load mass or be arranged on the battery side. In fuel systems of Internal combustion engines, in particular directly injecting Otto or Diesel engines, for example, the fuel flow to the high-pressure pump regulated with a quantity control valve. The quantity control valve is operated by an electric motor actuator, seen electrically represents an inductive load. The coil windings of the actuator are not for permanently switched on, they become thermal after a short time destroyed. This case is particularly significant when a masseside switched with a so-called "low-side switch" (LSS) Load experiences a ground-side short to ground, the Switch is thus bridged. In this case occurs in seconds, the thermal destruction of the Actor.

Usually is the battery side another switch, namely a Main switch or main relay, with which the entire power supply the electrical components of the internal combustion engine is switched.

Problems of the State of the art

Opening the Main relay in the event of a fault has the consequence that all consumers are switched off. In addition, you can many short circuit failures that the actuator of the quantity control valve though do not destroy but fail, not to be diagnosed.

task The present invention is therefore a circuit and a Specify procedures that allow a more accurate diagnosis and opening the Avoid main relay.

Advantages of invention

This Problem is solved through a circuit for monitoring and controlling a load, in particular an inductive or ohmic load, the above a battery side switch with the battery side and a ground side switch is connected to ground, the circuit a device for measuring the low side voltage of the load and means for measuring the battery side voltage includes the load. The inductive or resistive load is in particular an electromagnetically operated Actuator of a regulated quantity control valve of a fuel system for an internal combustion engine. It can So battery side and mass of the load or the actuator, the equivalent circuit corresponds to a coil, each switched. The masseside and the battery-side switch are preferably a transistor, For example, a MOS-FET. In particular, the battery-side switch can with the device for measuring the battery-side clamping voltage the load or a device for measuring the battery side Current flow to the load combined in an integrated circuit be. The supply of the load is in case of failure in a safe Operating state led.

The inventive circuit offers the advantage that the battery-side switch a shutdown the load in the case of a ground-side short to ground, so a bridging of the masseside Switch, allows.

The inventive circuit can in any case an inductive or resistive load, the invention So it is by no means limited to motor control applications.

Of the voltage-side switch and the ground-side switch may be preferred independently of each other through a control unit be switched.

In a preferred embodiment is provided that the voltage side switch an integrated Circuit is connected to an output, to which a current flow through the switch dependent Voltage is applied and an input, the switching operation of the voltage side Switch triggers, the output is fed back to the input so that the voltage-side switch when exceeded a current flow threshold is opened. It is therefore an e.g. in case of a short to ground, an overload or overtemperature self-opening Switch, similar to an overload protection. The low-side switch is preferably at ground-side overcurrent switched off, so it is a short circuit to battery voltage.

The problem mentioned at the outset is also solved by a method for monitoring and controlling an inductive or ohmic load, wherein the load is connected via a battery-side switch to the live side and a low-side switch to ground, means for measuring the ground side and batte rieseitig voltage applied to the electromagnet are present, characterized in that the ground-side switch is opened and closed and from the ground side and the battery side voltage applied to the electromagnets the presence of a fault and the type of fault is diagnosed. The method may be used, for example, in a solenoid-operated quantity control valve of a fuel system for an internal combustion engine.

in the Normal operation, a battery side short to ground is detected when the battery-side voltage exceeds an upper limit and the ground-side voltage when open and with closed mass side switch against a lower Value goes. Under normal operation, the operation of the internal combustion engine understood after completion of the boot process.

in the Normal operation, a ground-side short to the battery is detected if the battery side voltage does not exceed the upper limit and the ground-side voltage at open and closed low side switch goes to an upper value.

in the Normal operation is detected a ground-side short to ground if the battery side voltage does not exceed the upper limit and the ground-side voltage at open and closed low side switch goes to a lower value.

in the Normal operation becomes an open load or a short circuit on the ground detected and differentiated to ground at a resistive load when the ground side voltage with open massive side and open battery-side switch assumes different values.

in the Normal operation becomes a ground-side short to ground at a Ohmic load detected when the ground-side voltage when open battery-side switch and with open ground side switch goes against a lower value.

in the Normal operation, an open load is detected when the ground side Tension when open battery-side switch and with open ground side switch goes against a middle value.

in the Idle operation of the actuator becomes a battery-side short circuit detected to ground when the battery-side voltage is upper Exceeds limit and the ground-side voltage at open ground side switch goes against a lower value. Under idle mode, for example understood the start of the internal combustion engine.

in the Idle operation of the actuator becomes an open load or a faultless one Case detected and distinguished when the ground-side voltage at closed battery-side switch and with open ground side switch assumes different values.

in the Idle mode of the actuator, a fault-free case is detected when with the battery-side switch closed, the ground-side voltage when open low side switch goes to an upper value.

in the Idle mode of the actuator, an open load is detected when the Battery side switch is closed and the ground side voltage when open low side switch goes against a medium value.

in the Resting operation of the actuator is a ground-side short circuit to Ground detected when the battery side switch is open and the ground-side voltage when open low side switch goes to a lower value.

in the Resting operation of the actuator is a ground-side short circuit to Battery or a battery side short to the battery detected and differentiates when the battery side switch is open and the ground side voltage different values when closed has massive side switch.

in the Idle operation of the actuator becomes a battery-side short circuit detected to the battery when the battery side switch is open and the ground-side voltage with closed ground side switch goes against a lower value.

in the Resting operation of the actuator is a ground-side short circuit to Battery detected when the battery side switch is open and the ground-side voltage with closed ground side switch goes against an upper value.

The Procedure allows it, between an open load and a short circuit to the ground To distinguish mass with an inductive and ohmic load. The Method can not only in normal operation, but also in idle mode of the actuator, so if longer There are pauses between applying the load and also provides a safe fault diagnosis in idle mode.

The above-mentioned problem is further solved by a control device for an internal combustion engine with a circuit according to one of the directed to a circuit claims, which a method according to any of the claims directed to a method.

The Method may preferably be a programmable logic program Control executed be executed, for example, as an ASIC or in an EPROM be stored for processing by a control unit.

drawings

following is an embodiment of Present invention explained in more detail with reference to the accompanying drawings. there demonstrate:

1 an injection system for an internal combustion engine;

2 a circuit diagram of the control of a solenoid valve;

3a and 3b a flow diagram of the method according to the invention in normal operation;

4 a sketch of various stress states for carrying out the method according to the invention;

5a and 5b Running diagram of the method according to the invention during engine start;

6 a sketch for analyzing different stress states for evaluation in the method according to the invention.

In 1 a fuel system for an internal combustion engine is shown. The fuel tank 1 is via a support line 2 with a pre-feed pump 3 connected. The pre-feed pump 3 pumps the fuel via a delivery line 4 to a quantity control valve 5 , Here, the fuel is metered and over another line 6 to a high pressure pump 7 forwarded. The fuel is compressed to high pressures and passes through a delivery line 8th in a high-pressure accumulator 9 (Common rail). The high pressure accumulator is equipped with injectors 10 connected to the fuel in cylinders of an internal combustion engine 11 inject.

For pressure relief, the high-pressure side is hydraulically via a pipe 12 with the quantity control valve 5 connected. At the high-pressure accumulator 9 is still a pressure sensor 13 arranged over a data line 14 with a control unit 15 connected is. The control unit 15 is also via another data line 16 with an actor 17 of the control valve 5 and via a third data line 18 with the internal combustion engine 11 connected. Furthermore, the control unit 15 input lines 19 on, with which various input values, such as the accelerator pedal position of the motor vehicle, are recorded.

The high pressure control is via the quantity control valve 5 , The actual pressure in the high-pressure accumulator is determined by the pressure sensor 13 taken and to the control unit 15 forwarded. In the control unit, the respectively required position of the quantity control valve 5 recalculated and the actor 17 controlled accordingly.

2 shows a circuit diagram for controlling an electromagnet, which is a simplified equivalent circuit diagram for the actuator 17 according to 1 represents. The actor 17 is usually a -zB electromechanical- switching valve, which can be shown in a first approximation as a solenoid or inductive load IL. This is connected via a battery-side switch HSS (high-side switch) with the generally positive supply voltage VBATT, which generally represents part of the battery voltage of the electrical system of a motor vehicle. Furthermore, the solenoid IL is connected to the ground GND via a ground-side switch LSS (low-side switch). The low side switch LSS is usually a field effect transistor. The battery-side switch HSS can be, for example, a field-effect transistor. The switching process is triggered via the input HSS. For the sake of clarity, the switch HSS and its input HSS are designated identically. A first voltage measuring module UAB1 supplies at its output HS-D a signal depending on the potential of the battery side of the load IL.

The ground-side switch LSS is connected via a control line LSS to a controller CTR. Again, switch and its control input are identically labeled. A second voltage measuring module UAB2 supplies at its output LS-D a signal depending on the potential of the ground side of the load IL. The controller CTR controls and monitors all functions of the quantity control valve 5 or general functions of the connected load IL. If the level LOW is present at the control line LSS, then the ground-side switch LSS switches on, the level at the control line LSS is high, then the ground-side switch LSS blocks.

About one Resistor Rref becomes a reference potential for the voltages HS-D and LS-D provided.

3a and 3b show the course of the method according to the invention during normal operation of the internal combustion engine. 4 shows an associated diagram of the various in 2 present inputs or outputs shown the voltage level. The error status is shown from top to bottom, indicating whether there is an error (ERROR) or not (OK), the position of the battery-side switch HSS closed (ON) or open (OFF), the level at the output HS-D of the voltage measuring module UAB1 (HIGH or LOW), the position of the low-side switch LSS with the positions closed (ON) or open (OFF) and the voltage at the output LS-D of the second voltage measuring module UAB2. The bottom line shows the respective errors. TSS denotes a transistor switching sequence.

Instead of high or low are for HSS and LSS OFF and ON indicated, for LSS this means OFF signal an open one ground side switch LSS and the ON signal a closed low-side switch LSS (the switch is thus active low). For the voltage values of the signal to LS-D, exemplary voltage values have been given. A value 0 V to 1.5 V here denotes a voltage SCG at short-circuit with the mass (SCG = Short Circuit to Ground), a value 3.5 V to 5V a voltage SCB at a short circuit with the battery side (SCB = Short Circuit to Battery), a voltage 1.5V to 3.5V a Voltage value OL, the circuit interrupted on the ground side (Open Load = OL) occurs. Exemplary values are given here, which depending on the design of the circuit can be higher or lower.

Based on 3a and 3b the sequence of the procedure is shown. It should first be noted that when the method is started, a so-called "pullin pulse" is applied to the signal line LSS, optionally, after this longer pulse, a pulse train of rectangular pulses is applied during which the method described here is used it is first determined whether the signal HS-D is equal to 0. If this is the case, then there is a short circuit of the battery-side terminal of the electromagnet IL to the ground side or there is an overload or over-temperature at the electromagnet in a next step measured whether the voltage applied to LS-D at about 3.5 to 5 V (SCB = Skiort Circuit to Battery) with open low-side switch LSS and at 0 V to 1.5 V (SCG = Short Circuit to Ground) at If this is the case, then there is no error and the procedure is terminated in the next step, it is measured whether the voltage LS-D reaches the value SCB, in this case 3.5 to 5 V, both when the battery-side switch LSS is switched on and off. If this is the case, there is a short circuit of the ground side to the battery (SCBLS = Short Circuit to Battery on Low Side). It then opens the low-side switch LSS to protect the electrical components.

Lies the aforementioned error case is not present, then in a next step measured whether the voltage LS-D both open and closed battery-side switch LSS 0 to 1.5 V, ie SCG = Short Circuit to Ground, reached. If so, there is a short circuit to the mass on the ground side (SCGLS = Short Circuit to Ground on Low Side). It is then the ground side switch LSS for Protection of load IL opened.

is this is not the case, it is determined in a further step whether the mass side switch LSS is connected to the LS-D Voltage equal to 0 V to 1.5 V, ie SCG, and when open low-side switch at 1.5 to 3.5 V (Open Load = OL) is located. In a next Step over that Signal HSS the battery-side switch HSS and the signal LSS the ground-side Open switch LSS. Thereafter, the signal LS-D is measured several times, for example three times. If the voltage lies in the range Open Load = OL, ie 1.5 to 3.5 V, there is the error of an open load (Open Load Error), e.g. through separate lines. If this is not the case, then it lies a short to ground on the ground side in an ohmic Resistance as a load (SCOGLS = short circuit to ground on low side with ohmic resistance).

A Switching sequence with the above-mentioned switching sequence of the ground-side and the battery-side switch is in this operating state for distinction between the cases the open load and a short circuit to ground on the ground side used in a resistive load. For the sake of clarity several possible Errors shown in a common diagram.

4 clarifies the previously explained values with the diagnosable errors. The error state or error free (OK) is shown in the "failure state" curve, below which are the voltage states HSS, HS-D, LSS with their logical values and LS-D with voltage values. D shown with dashed arrows and HS-D with solid arrows, so that in particular the signals HS-D and LSS can be assigned to the values LS-D.

5a and 5b show the procedure during a quiet operation of the actuator. Under idle mode is here understood an operating state in which the actuator remains unactuated for longer periods, for example, during engine start or idle. First, it is checked whether the voltage VBATT is present. If this is the case, then it is checked whether the signal HS-D is equal to 0. If this is the case, there is a short circuit as before the battery side to ground, overload or over temperature. If this is not the case, then the signals LSS and HSS are switched off and the signal LS-D is observed. If the voltage of the signal LS-D in the range OL, ie 1.5 to 3.5 V, the switches HSS are turned on, the switch LSS remains off. Then the voltage LS-D is measured again. If this is in the range SCB, ie 3.5 to 5 V, then there is no error, the voltage is not in this range, it is determined whether the voltage is in the range OL, ie 1.5 to 3.5 V. , If this is the case, there is an error case of an open load. Was in the process step in which LSS and HSS are turned off, a voltage at LS-D outside the range OL, ie 1.5 to 3.5 V, not measured, it is determined in a further step, whether the voltage in the range SCG, ie 0 to 1.5 V, is located. If this is the case, there is a short circuit to ground on the ground side and the switch HSS is turned off as component protection. If this is not the case, it is determined in a further step whether the voltage at LS-D is in the range SCB, ie 3.5 to 5 V. If this is not the case, then the method is terminated with the diagnosis of freedom from errors; if this is the case, then in a further step the switch HSS is switched off and the switch LSS is switched on and the signal LS-D is measured. If the voltage at LS-D is in the range SCG, ie 0 to 1.5 V, there is a short circuit to the battery on the battery side and LSS is switched off. If this is not the case, it is measured in a further step whether the voltage applied to LS-D in the range SCB, ie 3.5 to 5 V, is located. If this is not the case, no fault is detected; if this is the case, there is a short circuit to the battery on the ground side and LSS is switched off. Here, two switching sequences are used, one for distinguishing between open load and faultlessness, another for distinguishing between shorting to the battery on the ground side and short to the battery on the battery side. For the sake of clarity, several possible errors are again shown in a common diagram

6 shows the procedure of the 5a and 5b corresponding sketch of the different switching states as shown in 4 ,

used Abbreviations the error cases

• OIL

  = Open Load (1.5V to 3.5 V) Open load

  SCGHS

  = (Short Circuit to GND high side) Short circuit of the battery side to ground

  SCOGHS

  = (Short Circuit to GND on High Side with Ohmic Resistance) Short circuit of the battery side to ground at resistive load

  SCGLS

  = (Short Circuit to GND Low Side) Short circuit to the ground on the ground side

  SCOGLS

  = (Short Circuit to GND to Low Side with Ohmic Resistance) Short to ground the ground side with ohmic load

  SCBHS

  = (Short Circuit to VBatt High Side) Short circuit of the battery side to the battery

  SCBLS

  = (Short Circuit to VBatt Low Side) Short circuit of the ground side to the battery

Claims (24)

Circuit for monitoring and controlling a load (IL), in particular an inductive or ohmic load (IL), which is connected via a battery-side switch (HSS) to the battery side (VBATT) and a low-side switch (LSS) to ground a device for measuring the ground side voltage of the load (IL), characterized in that the circuit comprises means for measuring the battery side voltage of the load (IL). Circuit according to the preceding claim, characterized characterized in that the supply of the load in case of failure in a safe operating condition becomes. Circuit according to the preceding claim, characterized in that the ground-side switch (LSS) and / or the battery-side switch (HSS) is a transistor. Circuit according to one of the preceding claims, characterized characterized in that the voltage side switch and the ground side Switch independent from each other by a control unit can be switched. Switch according to one of the preceding claims, characterized in that the ground-side switch (LSS) is switched off at ground-side overcurrent becomes. Switch to one of the previous An claims, characterized in that at battery side overcurrent through the HSS switch, this is turned off. Circuit according to one of the preceding claims, characterized characterized in that the reference potential either with the ground side or can be connected to the battery-side connection. Procedure for monitoring and controlling an inductive or ohmic load (IL), in particular a solenoid operated quantity control valve a fuel system for an internal combustion engine, wherein the load (IL) via a battery side Switch with the live Side and a ground side switch is connected to ground, being means for measuring the ground side and the battery side There are voltage applied to the electromagnet thereby characterized in that the ground side switch is open and is closed and from the mass side and the battery side the electromagnet voltage applied to the presence of a Error as well as the type of error is diagnosed. Method according to the preceding claim, characterized characterized in that a ground-side short to ground with ohmic resistance (SCOGLS) and load drop (OL) are detected and distinguished becomes. Method according to the preceding claim, characterized characterized in that in normal operation, a battery-side short circuit to ground (SCGHS) is detected when the battery side voltage exceeds an upper limit and the ground-side voltage at open and closed low side switch goes to a lower value (SCG). Method according to one of the preceding claims, characterized characterized in that in normal operation, a ground-side short circuit to the battery (SCBLS) is detected when the battery side voltage does not exceed the upper limit and the ground-side voltage when open and with closed ground side switch against an upper Value (SCB) goes. Method according to one of the preceding claims, characterized characterized in that in normal operation, a ground-side short circuit to ground (SCGLS) is detected when the battery side voltage does not exceed the upper limit and the ground-side voltage at open and closed low side switch goes to a lower value (SCG). Method according to one of the preceding claims, characterized characterized in that in normal operation an open load (OL) or a ground-side short to ground in resistive load (SCOGLS) is detected and distinguished when the ground-side voltage at open massive side and open battery-side switch assumes different values. Method according to one of the preceding claims, characterized characterized in that in normal operation, a ground-side short circuit to ground at resistive load (SCOGLS) is detected when the ground side Tension when open battery-side switch and with open ground side switch goes against a lower value (SCG). Method according to one of the preceding claims, characterized characterized in that detected in normal operation, an open load (OL) when the ground-side voltage with the battery-side switch open and when open low side switch against a medium value (OL) goes and at closed low-side switch against a lower value (SCG) goes. Method according to one of the preceding claims, characterized characterized in that in the idle mode of the actuator, a battery side Short circuit to ground (SCGHS) is detected when the battery side Voltage exceeds an upper limit and the ground-side voltage when open low side switch goes to a lower value (SCG). Method according to one of the preceding claims, characterized characterized in that in the idle mode of the actuator, an open load (OL) or an error-free case is detected and distinguished when the ground-side voltage with the battery-side switch closed and when open mass side switch assumes different values. Method according to one of the preceding claims, characterized characterized in that in the idle mode of the actuator a faultless Case is detected when the battery-side switch (HSS) is closed the ground-side voltage with the mass side open Switch (LSS) goes to an upper value (SCB). Method according to one of the preceding claims, characterized characterized in that in the idle mode of the actuator, an open load (OL) is detected when the battery-side switch (HSS) is closed is and the ground side voltage with open ground side switch (LSS) goes against a mean value (OL). Method according to one of the preceding claims, characterized in that at rest Operation of the actuator a ground-side short to ground (SCGLS) is detected when the battery-side switch (HSS) open and the ground-side voltage with open ground side switch (LSS) goes to a lower value (SCG). Method according to one of the preceding claims, characterized characterized in that in the idle mode of the actuator a masseseitiger Short circuit to the battery (SCBLS) or a battery short circuit to the battery (SCBHS) is recognized and distinguished when the battery side Switch open and the ground-side voltage different values when closed has massive side switch. Method according to one of the preceding claims, characterized characterized in that in the idle mode of the actuator, a battery side Short circuit to the battery (SCBHS) is detected when the battery side Switch (HSS) open is and the ground side voltage with closed ground side switch (LSS) goes to a lower value (SCG). Method according to one of the preceding claims, characterized characterized in that in the idle mode of the actuator a masseseitiger Short circuit to the battery (SCBLS) is detected when the battery side Switch open is and the masseseitige tension with closed masseseitigen Switch goes to an upper value (SCB). control unit for one Internal combustion engine with a circuit according to one of the claims directed to a circuit, the according to a method according to one of the directed to a method claims can work.