WO2012052273A2

WO2012052273A2 - Method and device for starting an internal combustion engine and changeover switching device

Info

Publication number: WO2012052273A2
Application number: PCT/EP2011/067076
Authority: WO
Inventors: Sven Hartmann; Falco Sengebusch
Original assignee: Robert Bosch Gmbh
Priority date: 2010-10-22
Filing date: 2011-09-30
Publication date: 2012-04-26
Also published as: CN103154499A; WO2012052273A3; DE102010042802A1; CN103154499B

Abstract

A method is described of a device (2) for a starter motor (5) for starting an internal combustion engine (30), in particular of a vehicle, for limiting an operating range of the starter motor (5) within predefined physical limits, wherein the electrical current (I₃₀) of the starter motor (5) is detected by a detection device (10) in the device (2). In order to allow a voltage drop in the on-board power supply of a motor vehicle to appear imperceptible for the operation of conventional loads during stop/start operation, electrical variables of the starter motor (5) are measured when current is applied, characteristic reference values are formed from the electrical variables, and when the characteristic reference values are above a critical reference value, it is deduced therefrom that the internal combustion engine (30) has started and the current is no longer applied.

Description

description

title

Method and device for starting an internal combustion engine and changeover device

State of the art

The invention relates to a method of a device for a starter motor for starting an internal combustion engine, in particular of a vehicle, for limiting an operating range of the starter motor within predetermined physical limits, wherein the electric current of the starter motor is detected by the detection device in the device. The invention further relates to a device for a starter motor of an internal combustion engine, in particular a vehicle, for limiting an operating range of the starter motor within predetermined physical limits with a detection device and an evaluation and control device for electrical quantities. The invention relates to a computer program product and a changeover device for a starting system with a starting device comprising a starter control, a starter motor and at least line connections for at least three subnetworks of a vehicle electrical system.

A starting device with a starter motor sets at a start request of a user an internal combustion engine in a vehicle in motion until the internal combustion engine runs itself. Thereafter, the starter motor is switched off. Switching off the starter motor is determined either by the user, the driver, even by releasing the ignition key or by means of a control device that detects the achievement of a minimum speed of the internal combustion engine, or after reaching a maximum period of time.

The following prior art is also known. DE 100 29 714 A1 describes a starting device for an internal combustion engine with a starter motor, a power supply and a control device for the starter motor. The drive device comprises a

Control unit and a power switching electronics. Sensors for detecting physical parameters relevant to the starting power of the starter motor, in particular the rotational speed, the torque and the current consumption of the starter motor, are provided in order to control the starting characteristic of the starter motor within permissible limits of the physical parameters.

DE 10 2006 039 112 A1 describes a simple and cost-effective method for calculating the rotational speed of a starter motor for starting internal combustion engines from various electrical variables, such as terminal and / or brush voltage and / or armature voltage of the starter motor, in a start-stop operation into an outgoing sprocket of an internal combustion engine at synchronous speed with a starter pinion of the starter motor einzu- trace.

DE 10 2008 040 681 A1 describes a method and a starter control for starting an internal combustion engine by means of a starter motor, wherein a starter current is controlled in the starting process defined by the starter control in order to prevent a voltage dip during a restart of an internal combustion engine in a start-stop operation ,

It is an object of the invention to develop a method, a device, a computer program product and a changeover device of the type mentioned in such a way that a voltage drop in the electrical system of a motor vehicle during a start-stop operation for operation of conventional consumers is imperceptible.

Disclosure of the invention According to the invention the object is achieved by the subject matter of claims 1, 7, 8 and 9. The dependent claims define preferred embodiments of the invention. It is an idea of the invention to use the starter motor in start-stop operation

Restart the engine with a higher voltage than the usual electrical system voltage of about 12 volts to apply to avoid a voltage drop well below 12 volts in Brodnetz. The higher one

Voltage can be supplied by feeding the starter motor, for example, from a secondary power source or by a boost converter, such as a DC / DC converter.

Converters take place when the vehicle electrical system voltage is lower.

The object is thus achieved by a changeover device for a starting system in that by means of the changeover device, the starter motor with different voltages can be acted upon, wherein the starter motor can be acted upon by the changeover device for a Nederstart in internal combustion engines in the start-stop operation with an increased voltage. Through the use of a higher voltage than the usually used vehicle electrical system voltage, the vehicle electrical system voltage does not break as much, so that electrical consumers who are turned on during start-stop operation by the vehicle user, are no longer turned off, or no longer adversely affected , The restart of an internal combustion engine during a start-stop operation can thus be performed imperceptibly for the vehicle occupant.

According to a further preferred embodiment, the changeover device comprises a test device, which checks whether consumers are active for the user in the vehicle during a stop in start-stop mode and only in the positive case, the starter motor with an increased voltage to Nederstart the Internal combustion engine can be acted upon. Thus, the starter motor is loaded with an increased voltage only in those cases where the vehicle user is actually desired to start imperceptibly. The test device can check, for example, whether an air conditioning and / or an audio or infotainment system are switched on, which require a stable vehicle electrical system voltage during a restart of the internal combustion engine. The object is achieved by a method in which characteristic values which are characteristic of electrical quantities of the starter motor when current is applied are formed and, if the characteristic comparison values are above a critical comparison value, it is derived from the fact that the internal combustion engine has been started and the current application is stopped. This avoids that the starter motor is operated with electrical variables that lead to high wear and a short life. As a result, the starter motor is operable even in a larger operating voltage range with a long service life. Furthermore, a conventional starter, which is designed for an operating range of about 12 volts as the vehicle electrical system voltage, continue to be used. A basic idea of the invention is thus after the start of the internal combustion engine, immediately from the time from which the internal combustion engine can continue independently, the starter motor or its speed defined to regulate and / or to control to obtain the life, especially of the starter motor, wherein the starter motor is preferably applied to a voltage higher than 12 volts.

Thus, it is avoided that the starter motor reaches inadmissibly high speeds, which are generated due to a higher voltage when the starter motor is no longer charged in the starting process of the internal combustion engine, because this is already started itself. The engine relieves the starter motor as it overruns the starter motor, i. the speed of the internal combustion engine is greater than the speed of the starter motor. In this case, the starter motor can be accelerated to its idle speed.

To safely avoid a voltage drop below 12 volts during start-stop operation, the starter motor for starting the internal combustion engine with at least two different voltages, in particular variable voltages, which are in particular at least 30% above the conventional electrical system voltage of 12 volts applied. This ensures that the voltage drop is reduced when the internal combustion engine is restarted. An influence on active consumers whose interruption the vehicle user would find disturbing is prevented. The object is also achieved by a device for a starter motor in that the device is formed with a detection device and an evaluation and control device for electrical variables of the starter motor, wherein the detection device comprises a current and a voltage device, and the control device comprises a power switching device to controllably switch the electrical energy of the starter motor, in particular to carry out a method described above. Thus, with a device that can have multiple functions effectively prevents a starter motor is operated outside its allowable operating ranges, which can lead to destruction. The starter motor can thus be operated effectively at higher voltage levels, being prevented by the inventive device that excessive idle speeds can be achieved. The device thus has an evaluation device which derives a speed of the starter motor from electrical variables, such as the armature current and the applied voltage, in order to energize the starter motor in a defined manner by means of a control device, or to regulate a defined rotational speed.

According to a further preferred method, from the characteristic comparison values, in particular from the measured current of the armature and a measured terminal voltage of the starter motor, a rotational speed of the

Starter motor calculates and checks whether the speed is below a limit speed, in case of exceeding the limit speed, the current application is abgeregelt. Thus, the starter motor is adjustable to a maximum speed, which is defined as a limit speed, which prevents the starter motor from reaching an inadmissibly high speed by applying an excessively high supply voltage, which can lead to damage or destruction of the starter motor. Under Abregein is also to be understood that the armature current is preferably also completely interrupted, especially when the internal combustion engine is started in order to avoid too high a speed.

According to a preferred method, the current application is reduced when a limiting speed or a critical comparison value is reached. That is, the current application is either completely interrupted, or according to a further preferred method, the speed of the star termotors regulated to a target speed. The speed is calculated from the following formula: _n _ 45 ^'30

k - Φ n = the armature speed

k-Φ = machine constant

R _starter = resistance of the starter motor

C / ₄₅ = the terminal voltage of the starter motor

L _n = armature current.

By measuring and evaluating the starter voltage U ₅ and the starter current 7 ₃₀ , the speed can be derived. The physical principle behind this is that the starter motor generates an induced voltage U _ind during rotation, which is proportional to the speed, the following formula follows:

From the measured electrical quantities and known parameters from the starter motor, the induced voltage can be calculated therefrom. ^ 45 ~ ^ 30 ^■ If necessary, a temperature influence can be taken into account.

Once the engine overhauls the starter motor, that is, the speed of the engine is higher than the speed of the starter motor, the starter motor can accelerate unloaded to its idle speed. The idle speed is primarily determined by the applied voltage, the

Motor constant and its internal friction of the starter motor.

To use the starter motor as efficiently as possible and to avoid high wear or high consumption of electrical energy is The starting current applied to the starter motor is switched off at a measured and evaluated speed of approx. 450 revolutions per minute.

Devices for controlling the starter motor, such as controlling the starting current when starting an internal combustion engine, are known

The object is therefore also achieved by a computer program product which can be loaded into a program memory with program instructions of a microcomputer in order to carry out all the steps of a previously or subsequently described method, in particular if the computer program product is executed in a device or control device described above. In this case, the microcomputer is preferably part of the device, wherein the control device, in particular in a plurality of devices in a system, a plurality of microcomputers and memory, as well as a plurality of computer program products or distributed to the plurality of devices may have a realized computer program product. The computer program product requires few or no additional components in the control device and may preferably be implemented as a module in an already existing control device. The computer program product can be stored on a physical medium, such as a memory chip, and has the further advantage that it can be easily adapted to individual and specific customer requirements and empirically determined values, and an improvement or optimization of individual method steps with little effort is possible cost-effectively.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively indicated combination but also in other combinations.

Brief description of the drawings

The invention will be explained in more detail below with reference to the drawings. Show it: 1 shows a schematic structure of a vehicle electrical system with inventive device,

2 shows a flow chart of a method according to the invention of a device according to the invention,

Fig. 3 is a time-current-speed diagram with respect to different voltages and

4 is a flowchart of a method of a changeover device.

1 shows a schematic circuit structure of a vehicle electrical system 1 with a starting system 20 and two electrical energy sources 8 and 9. The starting system 20 includes a device 2, a changeover device 3, a starter control 22 and a starter motor 5 with a Einspurvorrichtung 25. Die Einspurvorrichtung 25 For starting an internal combustion engine 30, a pinion 26 that can be driven by the starter motor 5 moves into a ring gear 36 of the internal combustion engine 30.

The changeover device 3 divides the vehicle electrical system 1 into three subnetworks A, B and C and has three line connections A1, B1 and C1 for this purpose. A first subnetwork A with a first power source 8 has a voltage of about 12 volts. A second subnetwork B with a voltage source 9 comprises a voltage higher than 12 volts, e.g. 20 V and to a third sub-network C, the start system 20 is connected, which is acted upon in each case with different voltages from the first two sub-networks A, B.

The changeover device 3 decides according to an inventive method described in FIG. 4, whether the starter motor 5 is subjected to a low voltage of about 12 volts or high voltage greater than 12 volts. Optionally, a higher-level control executes the decision step and controls the changeover device 3.

The starter motor 5 is applied according to the invention either exclusively with a voltage from a power source having a higher voltage than the 12th Voltage, for example, 16, 20 or even more volts or preferably it is from two sources of power operationally applied, the first power source 8 hereinafter "low voltage source" and the second power source 9 as a "high voltage source" with about 12 volts, for example, 20 volts , referred to as. The high voltage source is preferably a lithium battery or a double-layer capacitor with a variable voltage. Alternatively or additionally, the AC switching device 3 comprises a DC / DC converter, which increases or decreases the voltages for the subnetwork C with the starter motor 5.

The starter control 22 realizes at least two switching functions. In a first function, the starter controller 22 switches the circuit of the starter motor 5 and the Einspurvorrichtung 25 in a so-called key start when the internal combustion engine 30 is to be started from a cold state, so-called cold start. For this purpose, an activatable by the driver start button o- a Zündschlüsselumdrehung be provided. The circuit is controlled either manually or electronically after the start of the internal combustion engine, for example by timing or after reaching a minimum speed of the internal combustion engine, interrupted.

A second function is experienced by the starter control 22 in a start-stop operation of an internal combustion engine 30. Here, a previously operated internal combustion engine 30 is restarted according to certain criteria without a signal from the driver. The starter control 22 may each have a separate, parallel current path with switches and possibly an electronic control unit for the first and second functions. In FIG. 1, for reasons of simplification, a starter control 22 with a circuit breaker 4 is shown. The starter control 22 thus includes a circuit breaker 4 for both functions, which is controlled by an electronic control unit 7.

The device 2 is connected in series with the starter control 22 and has a further switch 6 in the circuit of the starter motor 5, which, as shown in FIG. 1, is connected in series with the switch 4. In particular embodiments, the switches 4 and 6 may be merged into a switch and the starter control 22 may include the device 2. The switches 4 and 6 are either relays or electronic circuit breakers such as MOSFETs.

The device 2 comprises a current measuring device 10 in order to detect the armature current I _{30 of} the starter motor 5 and a voltage measuring device I 1 in order to detect the voltage U ₄₅ applied to the starter motor 5. The device 2 further comprises a microcomputer with a program memory 13, which is used as an evaluation and control device 12 in the device 2 to calculate from the measured electrical variables according to a Rechenalgorythmus the actual speed n of the starter motor 5 and evaluate and thus check that the starter motor 5 is operating within a permissible speed range. If the starter motor 5 a limit speed n _Gre nz or a characteristic comparison value, which is formed of electrical variables exceed, so the microcomputer is active as a control device 12 by the basically closed switch 6, the current for the starter motor 5 limited by at least temporary opening or completely interrupts. Thus, it is avoided that the starter motor 5 impermissibly high speeds n of, for example, about 450 U / min. reached. The device 2, the alternating switching device 3 and the starter control 22 are preferably formed as separate Vorrich- lines. Alternatively, the devices are designed to be fully or partially combined. The starter motor 5 is thus protected and can be operated at higher voltages, which make a voltage dip when starting the internal combustion engine 5 imperceptible. FIG. 2 shows a flow chart as executed by the device 2 as a method according to the invention. At any time, the starter motor 5 is energized by closing the switch 4 in a step S1. The switch 6 is either already closed or closed at the same time as or shortly after switch 4, so that the starter motor 5 is subjected to voltage. The AC switching device 3, which can switch on either from the low-voltage source 8 or the high voltage source 9 electrical power, the consumer subsystem C in the start-stop operation of an internal combustion engine preferably supplied with high voltage from the voltage source. 9 In a following step S2, the device 2 is activated. Alternatively, the device 2 can be activated when the starter motor is subjected to a voltage with both high voltage and low voltage.

In a step S3, the current and voltage measuring device 10 and 1 1 begin to detect and measure the armature current i ₃₀ and the applied voltage U ₄₅ on the starter motor 5.

In a following step S4 is calculated from the current i ₃₀ and the sensed voltage U _45, the rotational speed n calculated according to the following formula, _n _ ^ 45 ^{~ '-} ^ 30

k - Φ

n

where ^{s, ar, he is} previously known as the internal resistance of the starter motor 5 and k-Φ is also known as the machine constant. Optionally, the influence of temperature is taken into account with a computing algorithm known from the prior art.

The control device 12 then proceeds to a query step A5, in which it is checked whether the calculated speed n is below or above a critical _limit speed n _limit . When a critical limit speed n _{exceeds the limit} of, for example, 450 revolutions per minute, the control device 12 changes over in step S6.

In step S6, the switch 6 is actuated, so that the switch is turned off and the starter motor 5 is no longer energized. Basically, it is assumed or checked whether at such a high _limit speed n _limit the starter motor 5 has started the engine 30 and this now runs independently, so that the control device 12 proceeds to step S7.

In step S7, the switch S4 is turned off and the switch 6 again closed electrically conductive or optionally also left open. If the speed n is below the _limit speed n _limit in the case of the query A5, a query step A8 is entered in which a query is made as to whether the internal combustion engine 30 has been started.

If this is the case, the control device 12 returns to step S7, if this is not the case, then in an optional step S9 the starter motor 5 is regulated with current so that the voltage dips when starting the internal combustion engine 30 are minimized. A current control may therefore be necessary to keep the starter motor 5 below a _limit speed n _limit . The lo procedure jumps again to query A5.

FIG. 3 shows a time-current-speed diagram for three different voltages U 12, Ui ₆ , U ₂₀ . The current characteristic curves l ₁₂ , I 16, l ₂₀ and the speed curves n ₁₂ , n ₁₆ , n _{20 of} the starter motor 5 are each plotted for 12 volts, 16 volts and 20 volts 15. For 12 volts, the current characteristic l _{12 is in} each case as a continuous

Characteristic drawn for 16 volts a dashed line l ₁₆ and 20 volts a dashed line l ₂₀ .

At a time t ₀ , the starter motor 5 is energized. In this case, at 12 volts 20 applied voltage briefly increases the starter current l ₁₂ - in this example - up to 800 amps. In this case, the rotational speed n ₁₂ rises until the time t ₃ wave-shaped due to the compression and decompression behavior of the cylinder in the internal combustion engine 30 to about 200 to 250 revolutions. At a time t ₅ , the internal combustion engine 30 overtakes the starter motor 5 in the rotational speed,

25 since the first ignition is done here, so that the starter motor 5, the internal combustion engine 30 catches up briefly again at one revolution at time t ₆ with 300 revolutions per minute again. Thereafter, the internal combustion engine 30 accelerates its speed significantly faster than the starter motor 5. Due to its design and the amount of voltage applied, the starter motor 5 comes

30 does not exceed a speed of about 420 revolutions per minute at time t ₇ , while the internal combustion engine has already reached idling speeds in the range of 800 to 900 revolutions per minute. Thereafter, the starter motor 5 is turned off and the starter pinion 26 spoked out of a ring gear 36 of the internal combustion engine 30.

35 Dashed lines show the current characteristic ₁₆ and the speed characteristic n ₁₆ at the voltage of 16 volts. At time t ₀ , a current peak I of approximately 1100 amperes is reached here at a voltage of 16 volts, which drops thereafter. The starter motor 5 accelerates the internal combustion engine 30 much faster than at the voltage Ui ₂ , so that even at the time t _3, which is well before the time t ₄ , the first upper Zündtotpunkt is reached. Since the internal combustion engine 30 accelerates much faster than the starter motor 5, the starter motor 5 already reaches an upper _limit speed n _limit of approximately 450 revolutions per minute at the second ignition dead center of the internal combustion engine 30 with the speed characteristic n ₁₆ at the time t _t . Because of the higher

Voltage Ui ₆ of 16 volts would reach the speed characteristic n ₁₆ * of the starter motor 5 to a speed n * up to the time t ₇ 600 revolutions per minute. This is a speed n *, for which the starter motor 5 is conventionally not designed and the starter motor 5 unduly loaded during prolonged use and thus limits the life. Therefore, according to the invention, the current for the starter motor 5 is interrupted at the time t4 by means of the device 2 via the control device 12 and the switch 6.

Thus, even at 16 volts, the conventional electrical system is burdened with consumers, not shown in FIG. 1, of 12 volts less, since the voltage drop is lower and at the same time a conventional starter motor 5 can be used, its speed n being limited by the device 2.

By means of dot-dash line are once the starter current l ₂₀ and the associated speed characteristic n _{20 drawn} upon exposure of the starter motor 5 with 20 volts. At the time t ₀ , the starter current I ₂₀ in the peak rises to almost 1400 amperes and then drops. The starter motor 5 reaches here already at the bottom dead center a speed of about 450 revolutions per minute at the time ti. This is sufficient to start the engine 30 at the time t ₂ with the first upper Zündtotpunkt, so that the engine 30 is very fast to the idle speed of about 800 revolutions and more per minute already at time e. With dashed line and colons the speed curve n ₂₀ * is shown, if the device 2 would be omitted in the electrical system 1. The starter motor 5 would thus very quickly up to the time t ₇ to a speed n ₂₀ * of about 800 revolutions per Accelerate the minute. At time t ₂ , the speed n _{20 of} the starter motor 5 is reduced in proportion to the time since it is switched off. The switch-off time t _{2 of} the starter current l ₂₀ can also be made dependent on reaching an upper ignition dead center of the internal combustion engine 30 in order to ensure a safe start.

FIG. 4 shows a flow chart of a method sequence as it is run through by a device or the starter control 22 with a changeover device 3. In a step S10, the information is given to the starter controller 22 to start the engine.

In a query step A20, it is checked if it is a start-stop operation. If this is not the case, ie if a so-called cold start is present, then the starter motor 5 is supplied with current by the low-voltage source 8 and the internal combustion engine 30 is started in a conventional manner, as known from the prior art, in a step S30.

If a start takes place in the start-stop mode, it is checked in a second interrogation step A40 whether a consumer is active for the vehicle occupants. If this is not the case, the method goes over in step 30, since a voltage dip is not perceived by the vehicle occupants.

If at least one consumer is active, which is affected by a voltage dip and could be damaged or if the voltage dip of vehicle occupants could be distracting, the changeover device 3 switches to the high voltage source 9 in a step S50, so that the starting device 20 with a higher voltage than 12 volts is applied. Subsequently, we go through the process as described in FIG. 2 following step S1. All figures show only schematic not to scale representations. Incidentally, reference is made in particular to the drawings for the invention as essential.

Claims

claims

Method of a device (2) for a starter motor (5) for starting an internal combustion engine (30), in particular of a vehicle, for limiting an operating range of the starter motor (5) within predefined physical limits, the electric current (l ₃₀ ) of the starter motor (5 ) is detected by a detection device (10) in the device (2), wherein electrical quantities of the starter motor (5), when current is measured, from the electrical variables characteristic comparison values are formed and if the characteristic comparison values are above a critical comparison value thereof is derived that the internal combustion engine (30) is started and the current application is abgeregelt.

A method according to claim 1, characterized in that from the characteristic comparison values, the speed (n) of the starter motor (5) is calculated and checked whether the speed (n) is below a limit speed (n and in case of exceeding the speed (n) the electricity supply is reduced.

A method according to claim 1 or 2, characterized in that after a successful ignition of the internal combustion engine (30), in particular after reaching an upper Zündtotpunkts of the internal combustion engine (30), the starter motor (5) is de-regulated.

Method according to one of claims 1 to 3, characterized in that the speed (n) of the starter motor (5) is controlled to a limit speed (n, wherein in particular the speed (n) with the formula

U - R · I

- 3o_ is calculated, where (n) the armature speed, k-Φ the k - Φ

Machine _constant , R _starter the resistance of the starter motor, C / ₄₅ the terminal voltage and / ₃₀ = armature current. Method according to one of claims 1 to 4, characterized in that the starter motor (5) for starting the internal combustion engine (30) with at least two different voltages, in particular variable voltages which are in particular at least 30% above the voltage of 12 V, is applied ,

Method according to one of claims 1 to 5, characterized in that the starter current from the starter motor (5) at a speed (n) of about 450 U / min. is switched off.

Device (2) for a starter motor (5) of an internal combustion engine (30), in particular of a vehicle, for limiting the operating range of the starter motor (5) within predetermined physical limits, with a Leis device switching device, a detection device and an evaluation and control device for electrical quantities , wherein the detection device comprises a current and a voltage measuring device (10,1 1) and the control device (12) comprises a switching device for controllably switching the electrical energy of the starter motor (5), in particular a method according to one of claims 1 to 6 execute.

A computer program product loadable into a program memory (13) with program instructions of a microcomputer for carrying out all the steps of a method according to at least one of claims 1 to 6, in particular when the computer program product in the control device (12) according to claim 7 or a changeover device (3) Claim 9 is executed.

A changeover device (3) for a starting system (20) with a starting device which comprises a starter control (22), a starter motor (5) and at least line connections (A1, B1, C1) for at least three subnetworks of a vehicle electrical system (1), by means of the change-over switching device (3) of the starter motor (5) can be acted upon with different voltages, and the starter motor (5) by means of the changeover device (3) for a restart of the internal combustion engine (30) in start-stop operation with an increased voltage is acted upon.

10. changeover device (3) according to claim 9, wherein the changeover device (3) comprises a test device, which checks whether consumers are active for the user during a stop in the start-stop mode and only in the positive case, the starter motor (5 ) can be acted upon by an increased voltage for Nederstart the internal combustion engine (30).