WO2011131467A2

WO2011131467A2 - Method for operating an internal combustion engine in which a solenoid valve for injecting fuel is actuated

Info

Publication number: WO2011131467A2
Application number: PCT/EP2011/055018
Authority: WO
Inventors: Matthias Siedentopf; Thomas Wuerzbach; Andreas Schmitt; Bernd Wichert; Markus Krieg; Markus Rueckle; Erik Tonner; Edgar Gfroerer; Matthias Schnell; Andreas Mueller
Original assignee: Robert Bosch Gmbh
Priority date: 2010-04-20
Filing date: 2011-03-31
Publication date: 2011-10-27
Also published as: DE102010027989A1; WO2011131467A3

Abstract

The invention relates to a method for operating an internal combustion engine (10), in which a solenoid valve (14a-d) for injecting fuel is actuated, wherein a coil (16a-d) of the solenoid valve (14a-d) can alternatively be connected to at least one standard voltage source (26) and to a boost voltage source (30) for a boost phase (1), wherein the coil (16a-d) is connected to the boost voltage source (30) in place of the standard voltage source (26) depending on a current operating situation of the internal combustion engine (10) for a pick-up phase (2) of the solenoid valve (14a-d).

Description

description

title

A method of operating an internal combustion engine, wherein a solenoid valve is actuated for injecting fuel

State of the art

The invention relates to a method according to the preamble of claim 1, and a computer program and a control and / or regulating device according to the independent claims.

From the market fuel systems of internal combustion engines are known in which injectors to shorten switching times are often switched in a first phase (boost phase) of their control to a boost voltage, so that a particularly high first current in a magnetic coil (coil) to reach a maximum value once. The boost phase usually marks the beginning of an anchor movement as one

Initial acceleration of the anchor. The boost voltage is generated for example from a DC-DC converter from a vehicle battery and can thus be much higher than the battery voltage, so that a correspondingly higher first current flows in the coil. As a result, an armature of the solenoid valve can be accelerated more.

Often, the boost voltage is stored in a so-called boost capacitor. In a directly following the first current increase phase of the activation (tightening phase), the coil is switched to the opposite of the boost voltage smaller battery voltage to perform a residual armature movement. The tightening phase provides the anchor motion approximately until a maximum anchor stroke is reached. Frequently, the suit phase is followed by a third phase (holding phase). The coil is optionally with a further and compared to the first two phases operated smaller power. For controlling in the holding phase but also the battery voltage is used. The holding phase ensures that the anchor remains approximately at a constant stroke. Furthermore, it is known, the coil of the solenoid valve during each of the three

Phases either permanently put on a voltage, or to clock the coil in the manner of a two-point controller, so that can set a desired average current over a respective duty cycle.

Disclosure of the invention

The problem underlying the invention is achieved by a method according to claim 1 and by a computer program and a control and / or regulating device according to the independent claims. advantageous

Further developments are specified in subclaims. Features which are important for the invention can also be found in the following description and in the drawings, wherein the features, both alone and in different combinations, can be important for the invention, without being explicitly referred to again.

The invention has the advantage that a solenoid valve for injecting fuel (injection valve) can be operated at least temporarily with a higher current during a tightening phase, without the need for additional devices or constructive measures.

The invention is based on the consideration that, depending on a particular operating situation of the internal combustion engine, it may be necessary to energize a coil of the solenoid valve more strongly during a starting phase than is possible on the basis of a battery voltage and a resistance and an inductance of the coil per se would. Because the parameters of the coil are fixed, according to the invention, during the attraction phase of the solenoid valve, the coil is alternatively switched to the boost voltage which is higher than a standard voltage source (battery voltage), so that a current through the coil which is higher than a standard operating event is independent of external conditions to enable. It may be necessary to use the coil during the tightening phase to clock in the manner of a pulse width modulation or a two-point controller to prevent overloading of the coil. By such a higher current, for example, in some

Operating situations increased mechanical resistance of the armature or a low voltage of the battery can be compensated.

The invention is particularly easy to apply when the circuit of the coil using at least one predetermined register set with a respective control profile contained therein takes place, and if the current

Operating situation is used between two or more of the

Switch register sets. Such a register file consists for example of memory cells of a computer of a control and / or regulating device, and contains, for example, a sequence of control commands and / or of

Numerical variables (control profile), which can be used to control the solenoid valves.

A control profile can thus comprise the variables which are essential for the operation of the solenoid valve, in particular voltages, limit values for currents,

Duty cycles and / or the duration of the respective phases. It is advantageous that the control behavior of the solenoid valve can be completely and easily changed by a simple switching between different stored in the control and / or regulating registers sets.

This is preferably done when a respective solenoid valve is not activated.

The invention is particularly useful if the current operating situation is defined by at least one of the following variables or events: a starting process of the internal combustion engine; a temperature of the solenoid valve and / or the internal combustion engine; a magnitude of the boost voltage and / or a magnitude of the at least one standard voltage. Especially during one

Startup of the internal combustion engine can be a considerable

Reduction of the battery voltage come, especially if at the same time a temperature of the internal combustion engine or an environment is particularly small. Therefore criteria are provided by the named quantities or events in order according to the invention between different register sets to switch so that each optimal and adapted to the operating situation control profile is used.

The method according to the invention can be applied particularly universally and at the same time differentiated, if the drive profiles each comprise at least two phases, wherein in each of the phases at least temporarily the coil can be switched to the boost voltage source and / or the at least one standard voltage source, or Coil can be operated in a freewheel. This describes a multitude of possible applications. For example, it is possible to switch the coil of the solenoid valve in each case for a predetermined time to the boost voltage or the at least one standard voltage source. In this case, the voltage can be applied to the coil during an entire phase, or it can be switched once or several times between the boost voltage and the standard voltage during a phase. Likewise, at least temporarily, the coil can be switched to a freewheel, that is, it is not actively energized, wherein an existing energy in the coil either lossy degraded or used, for example, to charge a boost capacitor. Likewise, a clocking in the manner of a two-point controller is possible.

An embodiment of the method provides that the drive profiles comprise at least one lower and / or one upper switching threshold for at least one of the phases. This makes it advantageously possible to perform the control of the coil according to certain criteria, which can be specified by means of the switching thresholds. In particular, a use of

Switching thresholds suitable, a control of the coil in the manner of a

Perform two-level controller, the behavior of which can be influenced directly by the switching thresholds. A further embodiment of the invention provides that the drive profiles the

Boost phase, the pull-in phase and a holding phase of the solenoid valve, and that the phases are each associated with a lower and upper switching threshold for a current flowing through the coil, wherein depending on the switching thresholds, the coil to the boost voltage source and / or the at least one Standard voltage source is switched on, switched off or switched over or operated in a freewheel. So that can be for each the three-phase switching thresholds are specified for the current flowing in the coil, so that the behavior of the coil or the solenoid valve can be adjusted particularly well. In particular, this can accurately control an energy supplied to the coil to both ensure the function of the injector and to prevent possible overloading of the coil. Also, the timing of the connection of the voltages whose

Switching over or the activation of the coil can be advantageously made dependent on the respective switching thresholds (current thresholds). A particularly useful embodiment of the method is that a first set of registers has a drive profile in which the pull-in phase uses the boost voltage source and the switching thresholds of the boost phase, that at least one further set of registers has a drive profile, in which the pull-in phase comprises the at least one standard Voltage source and

Switching thresholds with respect to the boost phase smaller streams used, and that a standard set of registers has a Ansteuerprofil in which the tightening phase uses the at least one standard voltage source and standard switching thresholds, and that when a temperature of the

Solenoid valve and / or internal combustion engine is below a first temperature threshold, is moved in a starting operation of the internal combustion engine as follows: (a) during the starting operation, the first register set is used; (b) after the end of the startup process and / or after exceeding a threshold for the standard voltage source is set to one of the further register sets with smaller currents for the pull-in phase

switches; optional: (c) with rising temperature or after a certain time has elapsed, switching to another register set with even smaller currents for the starting phase; (d) step (c) is repeated as needed; and (e) when a second temperature threshold is exceeded or after a certain time has elapsed, the system switches to the standard register set.

This can advantageously be carried out a starting operation and subsequent operation of the internal combustion engine with an optimal control of the injectors. Low due to a low ambient temperature battery capacity, temporarily reduced by the startup battery voltage and / or due to the low temperature particularly viscous fuel can by means of various Register sets or the control profiles contained therein are balanced so that a respective target fuel quantity is injected as precisely as possible. Overall, the process works so graded by during the suit phase after the start of the launch of the

Internal combustion engine, the coils of the solenoid valves are initially operated with comparatively high currents, and then by switching the

Registers sets depending on the operating situation these streams are gradually reduced until finally the standard register set with the in the

Comparing lowest coil currents is used.

In addition, it is provided by the invention that at least one timer is started and / or evaluated depending on the current operating situation, and that after a predetermined time of the at least one timer to a standard register set for at least one waiting time is switched. This can be in the case of a constantly low

Battery voltage overload of the control and / or regulating device or an overload of the injection valves can be prevented by at least one time long (waiting time) is switched to the standard register set. Thus, the facilities of the internal combustion engine are spared and generated compared to the prior art, comparable injection quantities. The starting of the timer can be done for example at the beginning or at the end of the starting process of the internal combustion engine. Also, the timer may be used in addition to or alternatively to the temperature of the engine and / or injectors to incrementally switch the register sets as described above.

Furthermore, the inventive method provides that a number of activations of the coil of the solenoid valve during use of the boost voltage source using a map is limited, and that depending on the selected drive profile and / or in the

Control profile described at least one additional map is used alternatively or additionally, and that input variables of the map, the boost voltage, the at least one standard voltage and / or a speed of the internal combustion engine. In this way, the number of times using the boost power source

made actuations of the injectors are optimally limited, that is, by means of the various ones acting on the map

Input variables, the process can, so to speak, close to a

Limit area in which a malfunction or damage to the control and / or regulating device or the injection valves is possible, approach.

Hereinafter, exemplary embodiments of the invention will be explained with reference to the drawings. In the drawing show:

Figure 1 is a simplified diagram of an internal combustion engine with four

Injectors;

FIG. 2 shows a general first time diagram of a drive profile with a boost phase, a pull-in phase and a hold phase; FIG. 3 shows a second time diagram of a control profile with a greatly increased current compared with a standard control profile during the starting phase;

FIG. 4 shows a third time diagram of a control profile with a reduced current compared with FIG. 3 during the starting phase;

FIG. 5 shows a fourth time diagram of a control profile with a reduced current compared with FIG. 4 during the starting phase; FIG. 6 shows a fifth time diagram of a drive profile with one compared to FIG

Figure 5 reduced power during the attraction phase;

FIG. 7 shows a sixth timing diagram with a standard drive profile; and

Figure 8 is an excerpt of a block diagram of a circuit for performing the method.

The same reference numerals are used for functionally equivalent elements and sizes in all figures, even in different embodiments. Figure 1 shows a highly simplified schematic of an internal combustion engine 10 with four cylinders 12a to 12d, four injectors 14a to 14d and associated coils 16a to 16d. In the upper part of the drawing, a control and / or regulating device 18 is arranged with a computer program 20 contained therein, which can energize the coils 16a to 16d by means of four lines 22a to 22d. The control and / or regulating device 18 further comprises a map 23 and is fed on the one hand from a battery 24, which provides a standard voltage source 26, and from a boost capacitor 28, which provides a boost voltage source 30. The boost capacitor 28 is charged by means of a DC-DC converter 32 from the battery 24 to a higher battery voltage against a boost voltage. In the following, the terms "voltage source" and "voltage" are used synonymously.

In operation, the control and / or regulating device 18 for supplying current to the coils 16a to 16d can access both the standard voltage source 26 and the boost voltage source 30. In this case, depending on a temperature 34, a timer 35, and a speed 36 of the

Internal combustion engine 10, the respectively more suitable voltage source for

Energization of the coils 16a to 16d selected.

Figure 2 shows a timing diagram of a general Ansteuerprofils 38 for an injection valve of the internal combustion engine 10. The abscissa of the coordinate system shown, a time between zero and 1300us (microseconds) is plotted. On the ordinate, a coil current is plotted in a range between zero and 16A (amperes). From left to right, three areas are marked by the numbers 1, 2 and 3 as a boost phase 1, a starting phase 2 and a holding phase 3 during energization of the solenoid valve. In the present case, the presentation of the current corresponds to the prior art. Although the function is explained below using numerical values. However, these are purely exemplary and, of course, may be completely different in other embodiments and operating situations.

In the first region, that is to say the boost phase 1, a steep and approximately rectilinear increase in the coil current takes place in a period of time from zero to about 100 μs, the current being taken from the boost capacitor 28, which is used as a boost.

Voltage source 30 is used. The boost phase 1 serves to anchor To start as fast as possible and to accelerate as much as possible. When reaching a maximum value of 40 in about 16A, the energization at the beginning of the tightening phase 2 is first turned off. There is a decay of the coil current up to a lower switching threshold 42 of about 9A. Then the power is turned on again, during the tightening phase 2 the

Standard voltage source 26 of the internal combustion engine 10 is used. When reaching an upper switching threshold 44 of about 10A, the coil current is switched off again, whereupon it continuously drops. Upon reaching the lower switching threshold 42 of FIG. 9A, this is in turn turned on and so forth. On average, during the attraction phase 2, a coil current of approximately

9.5A on. The achievable in the tightening phase 2 coil current is essentially limited by a height of the battery voltage dependent standard voltage source 26 and a resistive coil resistance. The tightening phase serves to maintain the anchor motion.

It should be noted that the switching thresholds set in the control and / or regulating device 18 may possibly deviate from the currents denoted in FIG. 2 and the following FIGS. 3 to 7. This is due to possible delays in the switching behavior of

Power switch so that it can come to overshoots or undershoots.

The holding phase 3 following the tightening phase 2 differs in the present case from the tightening phase 2 by smaller coil currents or by correspondingly smaller threshold values. Above all, it serves to keep the armature and thus also the injection valve in an open position. On average, during the hold phase, a coil current of approximately 7A is generated using a lower switching threshold 46 of approximately 6.5A and an upper switching threshold 48 of approximately 7.5A. After holding phase 3, the coil current is completely switched off until the next cycle.

FIG. 3 shows, according to the invention, a first register set with a

Ansteuerprofil 38, which allows in the tightening phase 2 an increased coil current. In the present case, the boost phase 1 ends at a time t1 of approximately 5.1 ms (milliseconds), the pull-in phase 2 at a time t2 of approximately 5.4 ms and the hold phase 3 at a time t3 of approximately 5.5 ms. The higher coil current during the pull-up phase 2 is achieved by using, unlike in FIG. 2, the boost voltage source 30 instead of the standard voltage source 26 to drive the coils 16a to 16d. A lower switching threshold 42 is about 12, 5A and an upper

Switching threshold is about 14.5 A and is therefore significantly higher in comparison to the standard current of FIG.

It can be seen that in the figure 3, the boost phase 1 seamlessly merges into the tightening phase 2, from which it can be deduced that the respective injection valve 14a to 14d can open fast enough even with a cold and viscous fuel to inject a required amount of fuel. The subsequent holding phase 3 has a mean coil current of approximately 6A and does not differ significantly from a standard energization of the coils 16a to 16d.

The control profile 38 shown in FIG. 3 is activated during a starting process of the internal combustion engine 10 and preferably at temperatures of the engine

Injectors 14a to 14d and the internal combustion engine 10 used, which are below a predetermined threshold. However, it may be useful to keep the register set shown in FIG

Start operation of the internal combustion engine for a predetermined period of time to apply, if the temperatures of the injectors 14a to 14d or the internal combustion engine 10 is still below a predetermined

Temperature threshold lie. After expiration of the predetermined time period, in any case, the register set shown in FIG. 3 is no longer used, at least for a subsequent waiting time, in order to rule out malfunctions or overloading of the injection valves 14a to 14d, the control and / or regulating device 18 or the internal combustion engine 10.

FIGS. 4 to 6 show register sets according to the invention with control profiles 38, such as may be used, for example, successively in time on the register set shown in FIG. 3 or the control profile 38 shown there. All embodiments according to FIGS. 4 to 6 have in common that the standard voltage source 26 is used during the starting phase 2 in order to energize the coils 16a to 16d. The differences in the actuation profiles 38 of FIGS. 4 to 6 consist essentially in the fact that different values are used for the lower switching thresholds 42 and the upper switching thresholds 44, so that in each case different mean coil currents occur during the tightening phase 2. In the illustrations of FIGS. 4 to 6, these average coil currents amount to approximately 13.5A, 12A and 10A.

FIG. 7 shows a standard register set with a standard control profile, in addition to the representations of FIGS. 3 to 6.

This results, for example, in the following sequence, taking into account FIGS. 3 to 7:

(a) during the starting operation of the internal combustion engine 10 and when the

Temperature of the injectors and / or the internal combustion engine and the battery voltage below predetermined thresholds, is the

Ansteuerprofil used according to the figure 3, while a timer is started at the beginning or at the end of the startup;

(B) after completion of the starting process and if at the same time the temperature of the injectors and / or the internal combustion engine, a lower

Temperature threshold exceeded and the battery voltage a

Voltage threshold have been exceeded, is switched to the register set of Figure 4;

(c) when the temperature rises, when the predetermined further temperature thresholds have been reached, the register sets of FIGS. 5, 6 and 7 are successively switched; and

(d) in any case, after the lapse of a time period predetermined by the timer, the system switches to the standard register set of FIG. 7 for at least one waiting period.

Figure 8 shows an excerpt of a block diagram for the control of

Injectors 14a to 14d, as in the control and / or regulating device 18th can be used. In this case, a number of (unspecified) input variables are linked to a number of output variables (not explained in more detail) by means of Boolean or mathematical operations.

In the upper left part of the block diagram, inter alia, two quadruple switches 50 and 52 are shown, with which a temperature sensor can be selected to selectively use a fuel temperature, an engine temperature or a cooling water temperature for carrying out the method according to the invention. A block 54 in the middle of FIG. 8 describes four sets of registers or four control profiles 38 contained therein. In the drawing to the right of the block 54, a block 56 is arranged, by means of which a voltage of the battery 24 determined in a block 58 can be taken into account.

Claims

claims

1 . Method for operating an internal combustion engine (10), in which a

Solenoid valve (14a-d) is actuated to inject fuel, wherein a coil (16a-d) of the solenoid valve (14a-d) to at least a standard voltage source (26) and for a boost phase (1) to a boost voltage source ( 30) can be switched alternatively, characterized in that depending on a current operating situation of the internal combustion engine (10) for a starting phase (2) of the solenoid valve (14a-d), the coil (16a-d) to the boost voltage source (30) Position of the standard voltage source (26) is switched.

2. The method according to claim 1, characterized in that the circuit of the coil (16a-d) using at least one predetermined register set with a respectively contained therein control profile (38), and that the current operating situation is used to between two or to switch several of the register sets.

3. The method according to claim 1 or 2, characterized in that the

current operating situation is defined by at least one of the following variables or events:

a starting operation of the internal combustion engine (10);

a temperature (34) of the solenoid valve (14a-d) and / or the

Internal combustion engine (10);

a magnitude of the boost voltage (30) and / or a magnitude of the at least one standard voltage (26).

4. The method according to at least one of the preceding claims, characterized in that the drive profiles (38) each comprise at least two phases, wherein in each of the phases, at least temporarily, the coil (16a-d) to the boost voltage source (30) and / or the least a standard voltage source (26) can be switched, or the coil (16a-d) can be operated in a freewheel.

A method according to claim 4, characterized in that the

Ansteuerprofile (38) at least one lower and / or upper

Switching threshold (42, 44, 46, 48) for at least one of the phases.

A method according to claim 5, characterized in that the

Ansteuerprofile (38) the boost phase (1), the tightening phase (2) and a holding phase (3) of the solenoid valve (14a-d) include, and that the phases depending on a lower and upper switching threshold (42, 44, 46, 48) for associated with a current flowing through the coil (16a-d), wherein in dependence on the switching thresholds (42, 44, 46, 48), the coil (16a-d) to the boost voltage source (30) and / or the at least one Standard voltage source (26) is switched on, switched off or switched over or operated in a freewheel.

Method according to at least one of the preceding claims, characterized in that a first register set has a drive profile (38), in which the starting phase (2) uses the boost voltage source (30) and the switching thresholds (42, 44) of the boost phase (1) in that at least one further set of registers has a control profile (38), in which the tightening phase (2) uses the at least one standard voltage source (26) and switching thresholds (42, 44) with smaller currents than the boost phase (1), and in that one Standard register set has a Ansteuerprofil (38), wherein the tightening phase (2) uses the at least one standard voltage source (26) and standard switching thresholds, and that when a temperature (34) of the solenoid valve (14a-d) and / or internal combustion engine (10) below a first

Temperature threshold, at a startup of the

Internal combustion engine (10) is operated as follows:

(a) during startup, the first register set becomes

used;

(b) after the end of the starting process and / or after exceeding a threshold for the standard voltage source (26) switched to one of the further register sets with smaller currents for the starting phase (2); and further optional:

with increasing temperature (34) will be on another

Register set switched with even smaller currents for the tightening phase (2);

Step (c) is repeated as needed; and

when a second temperature threshold is exceeded is switched to the standard register set. 8. The method according to at least one of the preceding claims, characterized in that at least one timer (35) is started and / or evaluated depending on the current operating situation, and that after a predetermined time of the at least one timer (35) to a standard Register set is switched for at least one waiting time.

Method according to at least one of the preceding claims, characterized in that a number of activations of the coil (16a-d) of the solenoid valve (14a-d) during use of the boost voltage source (30) is limited by using a characteristic map (23), and that, depending on the selected drive profile (38) and / or the phases described in the drive profile (38), at least one further characteristic map (23) is used alternatively or additionally, and that input variables of the characteristic map (23) are the boost voltage (30). comprising at least a standard voltage (26) and / or a rotational speed (36) of the internal combustion engine (10).

Computer program (20), characterized in that it is suitable for carrying out the method according to at least one of the preceding claims.

1 1. Control and / or regulating device (18), characterized in that on it a computer program (20) according to claim 10 is executable.