EP1312773B1 - System for compensating the phase deviation of an adjustable camshaft and corresponding method - Google Patents

Description

The invention relates to a system for eliminating the deviation the actual angle of an adjustable, in particular continuously adjustable camshaft from one Predeterminable target angle when an engine is idling, one being Control or regulating device for controlling or regulating the Camshaft position and a control unit for Motor control is provided.

For engines, especially vehicle engines with camshafts are known that have a continuously adjustable Have camshaft. The adjustment is made via a oil hydraulic system or an electric motor accomplished. The regulation of the camshaft position takes place via control valves, which go from the control unit Motor control can be controlled. The Camshaft adjustment takes place over the entire Speed and load range. Deviations from the determined Target positions of the camshafts lead to losses in Driving comfort as well as performance and deterioration of Emission values and consumption.

The camshafts are idle non-overlapping position, i.e. the entrance is open the latest and the outlet on the earliest position of the Camshaft. Different positions of the camshaft lead to restless engine running, which however should be avoided should. For convenience and consumption reasons, the Idle speed should be as low as possible. Occurs at idle however at oil temperatures from 80 ° C for example a very strong deviation of the camshafts from the target angle. This Deviation usually takes place until the late stop of the Auslassstellers. In older engines, this deviation is from the target angle only at higher oil temperatures observe. The deviation from the target angle when idling is This explains that with hot oil, this is a consequence of that oil becomes thinner at higher temperatures low oil pressure at idle and the increasing Frictional moments of the camshafts appear to be the Exceed the actuating force of the inlet and outlet actuators.

To solve the general problem of a Idle settings in internal combustion engines are in the state the technology showed some ways. For example DE 44 33 299 A1 describes a device and a Procedures that make it possible to increase the idle speed increase to provide adequate engine lubrication ensure if the operating state of a so-called Hot idling is achieved in which a low oil pressure and high oil temperature threaten to occur. In normal operation forms a setpoint formation unit depending on the supplied operating variables an idle speed setpoint, that of a control unit comparing with an actual speed set by actuating an actuator becomes. In the so-called hot idling, the speed setpoint becomes to a higher amount than normal operation Value switched when the oil pressure drops to low values threaten. This is recognized when there is an increase the oil temperature is calculated using a threshold value. On Switching takes place in hot idling by a provided Switching means. The target idle speed in the hot idle state is stored in a separate storage element. A changeover signal is formed when the motor for a predetermined time with a speed above one Limit speed and / or operated in a high load condition and, if applicable, the engine temperature and the Intake air temperature above specified limits lie.

DE 197 22 187 A1 describes a control method an adjustable cam spread at one Internal combustion engine in motor vehicles known. By means of a electronic control unit is from a basic map a minimal cam spread pre-controlled. A smoothness monitoring unit determines whether the minimal cam spread the internal combustion engine a smooth running limit exceeds. A spread adjustment unit increases the set cam spread as long as the Quiet running limit is exceeded. Object of this invention is to increase fuel consumption and royalty emissions minimize. The spread adjustment unit increases the set minimum cam spread in case of restless Engine running. A spread map for specifying a Setpoint of the cam spread is for the cheapest Environmental conditions, for example the lowest possible Ambient pressure or for vehicle operation in larger Designed for heights.

DE 100 02 352 A1 describes a valve timing control system for an internal combustion engine in which the Maintain controllability of the valve timing and the The combustion state of the internal combustion engine remains stable should. The valve timing control system includes one hydraulic actuator for changing an operating angle of a Camshaft cam to set a valve timing in the Advancing or decelerating the internal combustion engine.

DE 197 24 609 A1 describes a method for determination an optimal idling speed of an internal combustion engine known in which by gradually changing the Idle speed and comparison of old and new idle unrest an optimal idle target speed is determined. It finds an idle idle control due to speed fluctuations instead of. The idle target speed is regulated to ensure optimal operating behavior. While the method is reaching predetermined limit values the idle speed determined. One finds each gradual increase or decrease in idle speed instead of.

Various control methods are known in the art or monitoring the idle speed of an internal combustion engine known, in particular from DE 195 34 844 A1, the DE 40 16 099 A1 and DE 196 18 403 A1. In the DE 195 34 884 A1 is based on an idle idle control Speed fluctuations thereby allow the gradient the course of the actual speed of the internal combustion engine determined and the manipulated variable for controlling the Idle speed depending on the amount of Gradient is determined when the amount of the gradient exceeds a predetermined threshold. The DE 40 16 099 A1 describes a device for Idle speed control, where a valve to change the intake air quantity of the internal combustion engine and, among other things. a Device for controlling the degree of opening of the valve are provided according to the machine speed. The DE 196 18 403 A1 discloses a control device for the Idle speed using an appropriate Sensors. The smoothness is at least based on signals an acceleration sensor arranged on the vehicle or a noise sensor provided in the vehicle interior determined.

Another method for adapting the characteristic of a Idle actuator is disclosed in EP 0 399 016 B1. An adaptation of an idle control via a Intake air mass flow achieved. One procedure and one Device for idle idle control is also in the DE 44 43 652 A1 discloses. Based on the comparison between a setpoint and an actual value for the speed a control deviation and manipulated variable are determined, whereby a pilot control and / or an increase in the setpoint in Depending on the speed is provided. By a Device for setting the course of movement of the Gas exchange valves of the internal combustion engine, one Camshaft has a controller that provides a control signal for an actuator of an actuator for introducing the Camshaft generated, the control signal is additive by Feedforward corrected. This serves a more comfortable Operation of the internal combustion engine also in transient operation and in the case of large dead times of the device for adjusting the Movement course of the gas exchange valves, these can be adjusted faster and the controller only Inaccuracies in feedforward control compensated.

From EP 0 808 997 A1 and EP 0 990 775 A1 are more Adjustment options for camshafts are known. Are there first and second camshafts and means for changing the Rotation phase of the first and second camshafts provided to a change in the opening and closing time curve of the To cause intake valves. In EP 0 990 775 A1 Influence on a three-dimensional cam of the camshaft taken and is an actuator for changing the valve lift provided by adjusting the positions of the camshaft along the axis of rotation of the three-dimensional cam, the valve lift through this three-dimensional cam is caused. It should be a suitable one Rotational speed of the internal combustion engine are generated.

There is therefore none in the above prior art Solution that the strong deviation of the adjustable Camshafts, especially the exhaust camshafts, in Idling at oil temperatures above a certain specific Limit temperature prevented from the actual target angle. Such a deviation usually takes place until Late stop of the exhaust actuator. Older engines can such a deviation from the target angle only at higher ones Oil temperatures can be observed. This deviation in Idling with hot oil seems to be a consequence of that higher temperatures thinning oil, the low oil pressure at idle and the increasing Frictional moments of the camshafts that affect the positioning force of the Steller exceed to be. A way to The above problem can be improved However, do not remove the state of the art.

JP-A-11-148381 discloses an adjustable camshaft, to provide an intake valve and an exhaust valve. On Camshaft angle sensor adjusts the intake valve. In addition, first and second oil approvals are for one Camshaft adjustment provided. The intake valve will changed and based on a variable valve adjustment on the camshaft angle signal and the crankshaft angle signal. The target speed of an idle speed controller and the opening of an idle speed control valve will be on a greater value compared to the normal operation of everyone variable valve adjustments set as soon as a variable Valve adjustment shows no normal time progress.

JP-A-07-119526 also discloses an adjustable one Camshaft, an intake valve and an exhaust valve. In addition, a bypass line is provided with a Throttle valve. An idle speed control valve (ISCV) opens and closes to adjust the amount of intake air in the Middle of the bypass line to stabilize the idle. To change the opening and closing times of the Intake valve is a variable valve timing (VVT) intended. Control is based on the deviation the current valve adjustment from the target valve adjustment a correction value for the opening of the Idle speed valve calculated.

The present invention is therefore based on the object a system to correct the deviation of the actual angle of the adjustable camshaft from a predetermined target angle to create in the idle of an engine, being just one strong deviation when idling at higher oil temperatures no longer occurs or is remedied.

This task is performed by a system based on the generic term of Claim 1 solved in that a device for Raising the engine idle speed is provided when a predeterminable value of the deviation is exceeded the actual angle of the camshaft from the specified target angle can be activated. Developments of the invention are in the dependent claims defined.

The invention is based on the knowledge that Raising the speed the deviation of the target and actual angle is reduced. The is particularly advantageous Idle speed increased via the engine control. It This results in the advantage of a smoother engine running even at higher oil temperatures at idle, which makes the Driving comfort, but also performance, emissions and the Vehicle consumption can be significantly improved. By doing Moment in which a predefinable threshold value of the Angle deviation is exceeded, the system activates the device for increasing the engine idling speed. In doing so, the limit is exceeded the oil temperature checked to be a slowly adjustable Camshaft with cold engine not to activate one To cause idle speed increase. Raising the Idle speed is preferably carried out via the control unit for engine control. The system thus serves to correct the Deviation of the actual angle from the nominal angle of the camshaft by increasing idle speed. Because the actual angle of the Camshaft position queried with the specifiable setpoint compared and an adjustment of the Camshaft position by increasing idle speed is made to the actual camshaft angle again to set the target angle is thus constantly Corrected camshaft position so that a Deviation of the actual angle from the target angle not or only in an approved tolerance range occurs.

The system of the invention can in any position Camshaft are used, so even at maximum Overlap and with no overlap position.

A device for rotating a camshaft opposite the crankshaft in a motor vehicle internal combustion engine known for example from DE 43 40 614 C2. Here will however by an electrical to be calculated Control signal an adjustable actuator for rotating the Camshaft adjusted in relation to the crankshaft. That too calculating control signal is from a Basic control signal that any difference between the The actual position and the target position of the camshaft are assigned is one of the oil temperature and the speed of the Internal combustion engine dependent correction value and from a Adaptation value calculated. The rotation of the camshaft will therefore not dependent on the idling speed of the Motor adjusted or the deviation of the actual angle from Target angle of the camshaft position for adapting Idle boost used. The twist refers directly on the control of the camshaft without further Integration of the engine idling speed in the Control system.

adjustable camshafts or a camshaft position control is also used in the prior art to control the Idle speed learning of an engine with internal Combustion used, as disclosed in DE 196 47 182 C2 or to control fuel injection as in the DE 196 35 042 C2. Taking into account the adjustable camshaft when controlling the Includes fuel injection according to DE 196 35 042 C2 also applying a compressive force to the camshaft and changing the rotational phase of the camshaft with respect to Synchronous pulley or crankshaft to a maximum Lead angle of a maximum lag angle so that the Closing control on the intake valves forward is moved. In the opposite case, the turning phase of the Camshaft with respect to the synchronous pulley maximum lag angle changed from maximum lead angle, so that the opening timing or the Opening timing of intake valves delayed is. The learning value is based on the ratio real valve characteristic (actual cam angle) too the valve characteristics for the engine in full heated state compensated. So here, too, none Referenced to the engine idling speed since the Engine fuel injection is to be controlled.

Preferably, according to the present invention Device for raising the idle speed a control unit and / or acts on the motor, in particular directly or via its control unit. This is not just the fastest, but also most direct way to act on given the idle speed.

The speed can preferably be increased continuously, as soon as a deviation of the actual angle from the target angle occured. Preferably, the device for Increasing the idle speed a continuous Speed increase from the speed at which the deviation occured. This increases the idle speed from a determinable value that is at least in is close to the desired idle speed. It must thus no adjustment from zero take place, what with a longer settling time would be connected.

Preferably, to generate defined ones Idle speeds a quantization of continuous Speeds. This makes it possible to only define Allow idle speeds. The speed of the Idle speed increase between the quantized stages is preferably freely selectable. As a result, a Adaptation or adaptation to the respective application or the respective engine type. Alternatively, the Speed can be raised continuously. In particular, can an optional application-specific configurability of the system.

for recording the actual angle of the camshaft and delivering it of an actual angle signal is preferably an angle detection device intended. It is also preferred means for monitoring the exceeding of a Predefinable threshold value of the target angle / actual angle deviation and provided for emitting a signal. The angle detection device and are particularly preferred the facility to monitor the exceeding of a Predeterminable threshold value can be coupled to one another, so that the Device for monitoring the exceeding of the Predefinable threshold value directly the current one Can query actual angle.

It proves to be particularly advantageous that the Device for increasing the idle speed preferably an application-specific adaptive idling speed that learns emits. Thus, the idle speed does not have to be fixed above the Oil temperature are stored, which would lead to that the worst engine in new condition is the idle speed specifies what a for all engines over the entire term would mean minimal speed, e.g. of 750 rpm. Out However, for reasons of comfort and consumption Idle speed should be as low as possible, e.g. 560 rpm be. Learning idle speed means in this Context that the condition of the camshaft from the idle speed currently approached is assessed. in the in most cases this will be the last to be approached Idle speed. Is during a so-called learning ban the idle speed increases, for example by switching on an air conditioning compressor, etc. Learning release learned from this higher speed, because lower speeds then even worse in terms of Camshaft deviation are as the higher speed. comes the engine from idling again at higher speeds, he usually goes back to the last one he learned Idle speed. Then there is a camshaft deviation found, the idle speed increases until either the learning state is exited or the maximum permissible idling speed limit has been reached. However, will no camshaft deviation found, none occurs Activity on when there is no idle speed increase has taken place. Alternatively, under adjustable Boundary conditions initiate a re-attempt if a Speed increase is present. The backward learning is in Basically possible in the same way as teaching an increased speed. If the oil temperature drops and lies no error has occurred for an adjustable time preferably the relearning started.

Before activating the active Idle speed boost the states of powertrain, Brake system and motor queried by the system. A release occurs when the drive train is without frictional connection and / or there is a brake actuation signal and the engine is in Idle. Is by clutch or gearbox, especially automatic transmission, the adhesion in Drivetrain separated, this can be done using the Detect the absence of a speed signal. is If the engine is idling, this information is System provided. The idle is defined by the There is no accelerator pedal actuation or such low accelerator pedal actuation that there is none Speed increase comes. The existence of the Brake (pedal) actuation signal to activate the Idle speed boost can be advantageously configured and leads to increased security. There is a recognized If the brake fails, the function may stop Security reasons should preferably be blocked. There with a vehicle with an automatic transmission that from the transmission transmitted driving force increases with the engine speed, the vehicle standing on a slope could Put the gear into motion without applying the brake. The activation of the idle speed increase can therefore then configurable, preferably user-specific take place when there is a brake actuation signal, regardless of the presence or absence of one Grip of the engine with the wheels - not gear "N" or "P" for an automatic transmission - regardless of the brake application. Accelerator pedal actuation can be advantageous be excluded by querying idle. In principle, an adaptation according to the invention can also in an area in which the speed due to the accelerator pedal actuated is greater than the idle speed, however still too low to hold the camshaft position. However, such a case is relatively unlikely.

Preferably, the control unit of the engine and / or the Device for increasing the idle speed before activation the idle boost the presence of a Engine system function signal and an allowable Engine status signal in the form of an enable signal. This ensures that there is no error in the Engine system is present and the engine status is set in this way is that acting on the idle speed is safe is possible.

An engine system function signal is preferably at There is no error signal in the brake actuation detection, in the absence of an error signal in the camshaft control, if there is one Release signal of the camshaft control issued. On permissible engine status signal is preferred if present an engine idle signal and an engine speed signal below a predefinable speed threshold, in particular, 800 rpm. Because the idle speed boost is then active for security reasons, if there is no fault in the system and the engine is in the individual is in a predefinable state System and motor function parameters and their parameters Condition queried. To make sure that a Brake actuation signal is actually present is one Query provided that no electrical There is an error in the detection of the brake application. Around to avoid that the target angle / actual angle deviation of the Camshaft is present due to a system fault advantageously provided a query that no electrical Errors in the control of the camshafts, in particular Exhaust camshafts. To the camshaft position To be able to influence is preferably also a query to an approved camshaft control in the system contain. A suitable one for the idle speed increase Engine condition is idling and engine speeds are up are below a predefinable speed threshold. A Speed threshold of 800 U / min is only here exemplified and can be application-specific can be set.

The idle boost is preferably adapted Exceeding the deviation of the actual angle from the target angle the camshaft by a predeterminable value, in particular a value of 7 ° and when the actual angle runs away from Target angle and / or when the camshaft is close to your End stop and / or its late position, especially in an angle of 5 ° and when an error signal occurs over a predeterminable period of time, in particular longer than 0.1 seconds. The system thus advantageously has one Query about adapting the idle boost to determine if there is actually a target angle / actual angle deviation the camshaft angle, especially permanent. To a value for one it is preferred to define such a deviation Threshold set depending on the selected application and in a particularly preferred embodiment can be 7 °. It however, in other embodiments, it is also any one other angle values possible. Preferably at the same time queried whether the actual angle runs away from the target angle, that is the deviation of the angles from each other steadily increased. This makes the long-term advantageous Queried for a deviation. A detection of the For example, the actual angle may run away from the target angle by providing a filtered actual angle and comparison of the filtered actual angle with the current one Actual angle. A suitable filter is, for example a PT1 link. The existence of a target angle / actual angle deviation the camshaft angle can also be caused by this be found that the camshaft is close to its End stop, i.e. the so-called late position. Here too, a value for the end stop detection or Predetermined late position detection. In a special For example, this angle can be a value of 5 °. In other applications this can Value can be varied. Preferably at the same time Request provided that one from the Detected errors above conditions longer than one a certain period of time is present, i.e. an error signal via a predeterminable period of time occurs. This too it is recognized whether the target angle / actual angle deviation of the Camshaft angle a unique phenomenon or a is permanent condition that could be remedied.

Preferably, a learned idle speed increase be reset, particularly preferred if present an oil temperature signal at engine start that is smaller as a predefinable and / or critical oil temperature threshold, e.g. less than 100 ° C and / or if the Power supply and / or erasing the fault memory of the Engine control unit. When the external conditions change it can prove beneficial by the system learned for the previous external conditions Idle speed increase to change since the learned Idle speed increase if necessary for the new ones Ambient conditions are not appropriate and relearning the basis of the new conditions seems more difficult as a complete reset and restart of the Learning. A query as to whether at engine start the oil temperature is less than the critical oil temperature threshold is preferably with another query linked, which goes that a time delay of the Starting signal until the oil temperature signal is present takes place in order to ensure that the reset condition can be recognized reliably to ensure. The critical oil temperature threshold can can be selected for the specific application. A break the voltage supply preferably also leads to a Resetting the system or at least the device for Raising the engine idle speed. In the event of an interruption the voltage supply can otherwise be caused by this Malfunctions and errors in the idle speed increase, in particular in relation to the learned values that it is safer to interrupt the Power supply the learned speed increase completely reset. Because for security reasons Error signals are also queried by the engine advantageous when deleting the fault memory of the engine control unit the learned speed increase is also reset.

The idle speed increase is carried out by everyone conditions described above preferably after following scheme: When there is a speed request signal and the release signal initializes the system preferably a target idle speed value and the device to increase the idle speed preferably lifts the Idle speed value continuously with the specifiable Speed increase speed on. In particular, this can Speed increase speed can be selected to 20 U / s. However, any other values are also possible. Means for generating defined are preferred Speeds provided, in particular a quantization of the continuously raised idle speed over a Curve. This allows the idle speed only assume defined speeds, for example from the Noise development can be advantageous here.

Means for avoiding a conspicuous are also preferred gradually ramping up the idle target speed after the Quantization provided, especially slowed down Raise the idle speed via a ramp with a predetermined speed. This will make smoothing the quantized values of the idle speed, resulting in better driving comfort and more pleasant Noise leads.

The object underlying the invention is also achieved by a method for controlling an adjustable, in particular continuously adjustable camshaft one Internal combustion engine with a control or Control device for controlling or regulating the camshaft position is provided, solved when exceeding one Predeterminable value of the deviation of the actual angle of the Camshaft from the predetermined target angle, the device for Fix the deviation is activated and where the Installation on a control unit for controlling the engine acts to increase the idle speed. In addition, the task is accomplished through a regulation process idle oil pressure using an adjustable, in particular continuously adjustable camshaft one Internal combustion engine with a control or Control device for controlling or regulating the camshaft position is provided, solved when exceeding one Predeterminable value of the deviation of the actual angle of the Camshaft from the predetermined target angle, the device for Fix the deviation is activated and where the Installation on a control unit for controlling the engine acts to increase the idle oil pressure. The position of the camshaft is an advantageous indicator for oil pressure. By a control device for controlling the Speed of an internal combustion engine, especially for Use in a aforementioned system and / or in a the above methods, the object is achieved by that an input for capturing manipulated values of a adjustable camshaft, an input for the signal of the Cooling water temperature of a cooling water temperature sensor Input for the signal of the oil temperature Oil temperature sensor, an input for entering Speed values of a speed sensor, a means of Evaluate, an input for querying one or more other signal sources and at least one means for Affect the idle speed and / or the Engine idle oil pressure are provided. This can by providing only one control unit Advantages of the invention can be achieved.

In the control device, it is preferred that the signal source of the Idle operating state and / or the accelerator pedal position and / or an idle signal, especially one Engine management system is. The signal from the setpoint generator can preferably be a map. This is one greater variability and therefore better adaptation to changing operating conditions possible.

Figur 1

Diagramme einer Leerlaufdrehzahlanhebung bei Abweichung des Sollwinkels einer Auslassnockenwelle unter Verwendung eines erfindungsgemäßen Systems,

Figur 2

eine schematische Ansicht eines Steuergerätes als erfindungsgemäße Einrichtung zum Anheben der Leerlaufdrehzahl und/oder Erhöhung des Leerlauföldrucks eines Verbrennungsmotors,

Figur 3

ein Ablaufschema zur Veranschaulichung der Anhebung der Leerlaufdrehzahl und/oder der Erhöhung des Leerlauföldrucks unter Verwendung eines erfindungsgemäßen Systems bzw. eines erfindungsgemäßen Steuergerätes nach Figur 2, und

Figur 4a, b

zweigeteiltes Ablaufschema mit detaillierterer Angabe einzelner Abfrageschritte bei der erfindungsgemäßen Anhebung der Leerlaufdrehzahl und/oder des Leerlauföldrucks eines Verbrennungsmotors.

In order to explain the invention in more detail, an exemplary embodiment is described in more detail below with reference to the drawings. These show in:

Figure 1

Diagrams of an idle speed increase when the target angle of an exhaust camshaft deviates using a system according to the invention,

Figure 2

2 shows a schematic view of a control device as a device according to the invention for increasing the idling speed and / or increasing the idling oil pressure of an internal combustion engine,

Figure 3

2 shows a flowchart to illustrate the increase in the idle speed and / or the increase in the idle oil pressure using a system according to the invention or a control device according to the invention according to FIG. 2, and

Figure 4a, b

two-part flowchart with more detailed specification of individual query steps when increasing the idle speed and / or the idle oil pressure of an internal combustion engine according to the invention.

Figure 1 shows two diagrams to illustrate the Speed curve if the camshaft position deviates an adjustable camshaft from a definable one Target angle. This is included in this embodiment constant 0 °. The actual angle initially increases over time weak, subsequently after a threshold value is exceeded SW strong. The designation of the vertical axis of the first, the Diagram indicating camshaft position in FIG. 1, ° AS, means deviation of the nominal angle of the camshaft. In the The speed in revolutions shown in the second diagram per minute over time is at a camshaft angle of minus 20 ° at 560 rpm, which is an idle speed with smooth engine running and therefore good comfort and low Represents consumption. First of all, the deviation Camshaft position no consequences regarding the Idle speed. After exceeding the threshold the deviation of the actual angle of the adjustable camshaft of the predetermined target angle represents the invention System to increase the idle speed determines that this Threshold was exceeded and the actual angle steadily increased in a less favorable position. He also receives especially from a limit switch, the information whether the camshaft position is close to its End stop, i.e. the late position. In the in Figure 1 embodiment achieved Camshaft position almost the end stop of 22 °. It is also queried whether the deviation of the target angle of the actual angle is greater than the predefinable threshold value. This can be done after the threshold value SW and the increase in the deviation over time is affirmed become. The deviation of the setpoint from the actual value is at Exceeding the threshold so large that now it is checked whether this error is longer than a predetermined one Time period Δt persists. This is also in the Given embodiment of Figure 1. The time period Δt can be set to 0.1 seconds, for example. she can have different values depending on the engine and application accept.

As also in the exemplary embodiment in FIG. 1 see, after exceeding the time period Δt Idle speed increased in quantized steps, initially to a specifiable speed of 650 rpm and below to a predetermined speed of 700 rpm. The transition in the higher speed level occurs continuously via a ramp so as not to negatively affect driving comfort influence. The idle speed increases from the speed at which the deviation occurred, that is in the application from 560 rpm. The speed of the Increase in idle speed between the quantized stages, So the 650 and 700 U / min, can be set freely become. There is also a continuous increase in Idle speed possible. The respective type of raising is freely adjustable depending on the application.

The idle speed is increased until the Camshaft position back to the original one Setpoint reached, in the case shown to one Angle drops from 0 °. This in turn becomes the threshold SW exceeded, but now towards the given one Target angle. The system also queries this or recognized, whereby the continuous lifting of the Idle speed set and the idle speed to the meanwhile reached value, here 700 rpm, is held.

With the idle speed increase, the Idle oil pressure increases so that the one from your Exhaust camshaft deviates greatly from the target angle the desired target angle position returns. Simply by adjusting the camshaft position without Increase of idle speed or idle oil pressure no compensation with that in the regulating or control device actuator provided for the camshaft position possible. This requires additional provision at least one control device according to the invention, such as shown in particular in Figure 2, for example the camshaft position control device can supplement.

According to FIG. 2, a control device 1 has an input 2 for Acquisition of the control values of an adjustable camshaft in particular by a phase encoder 11, an input 3 for the signal of the cooling water temperature, an input 4 for that Oil temperature signal, an input 5 for entering Speed values and an input 6 for detecting Signals from one or more other signal sources. The Control unit receives via sensors, such as the phase encoder 11 adjustable camshaft 15, a speed sensor 14 of the Motors, a cooling water temperature sensor 12 and one Oil temperature sensor 13 signals and prepares them. One in the control device 7 included for evaluation evaluates the prepared values and acts on actuators 10, which is an idle speed boost of an engine 9 effect such as an idle speed control device.

The implementation of the processed and evaluated values can control unit 1 via the throttle valve actuators, Ignition, injection (for idle speed control) and camshaft control valves.

As a signal source for entering further signals via the input 6 of the control unit 1 can, for example, the Accelerator pedal position, an idle signal and the Idle operating state can be queried. The functions an engine management system can be in one or more Control units run, the use of only one Control unit proves to be less expensive. Speed sensor 14 for recording and delivering the idle speed values, Cooling water temperature sender 12, Oil temperature sensor 13 and phase sensor 11 of the adjustable Camshaft 15 are only indicated in FIG. 2. Instead of a single target angle, a is preferably used Set target angle map.

Figure 3 shows a flow diagram of the operation of a inventive system for increasing the idle speed of an internal combustion engine. In a first step continuously asking whether a deviation of the Actual angle from the target angle is greater than one predefined threshold value SW. Exceeds the deviation the threshold value is not exceeded, the query is continued. If the deviation exceeds the specified threshold, follows the query of a release signal. Is this also before, the idle speed increase is activated. However, the release signal is only available when a positive motor function signal and a permissible one Motor status signal present. In a fourth step initialize an idle speed value and then in a fifth step this continuously with a specified speed increase speed raised. In A sixth step is a quantization of the continuously increased speed via a characteristic curve performed. As a result, only defined idle target speeds set. In a seventh step, a slowed increase of the idle speed over a Ramp with a speed that can also be specified. On this prevents conspicuous step-up. In An eighth and final step will be achieved Idle speed is maintained and sent to an engine control unit output. The increase in the idle target speed will then ended when there is no deviation of the actual angle from the target angle the camshaft position occurs more than that predetermined threshold SW is.

The release signal is given when both a Engine system function signal as well as an allowable Engine status signal present. What factors these signals form, can be seen better in Figure 4a and b, the together represent a query scheme. Here is again a process is shown in which the factors of Forming a release signal and determining one Deviation of the actual angle from the target angle of the camshaft, the A predetermined threshold value is exceeded Deviation and resetting of the control unit or Systems for increasing the idle speed are reproduced. According to FIG. 4a, it is for the presence of the release signal and thus to activate the idle speed increase required that either no traction in the driveline which is e.g. by querying the gear selector lever can be determined regardless of the actuation of the Brake pedal, or the brake pedal is operated, which e.g. queried by a sensor in the area of the brake pedal regardless of whether it is loaded or not one speed step. So it will be the correct state of the Speed step and brake queried. The engine status signal, such as it is also indicated in FIG. 3, is formed by that the engine is idling, so on Idle signal is present and that the engine speed is up is below a predetermined speed threshold. Likewise, the activity of idle speed control queried. The engine system function signal is generated by the presence of a release signal from Camshaft control, that is an adjustment of the Camshaft is possible. In addition, no electrical should Errors in the control of the camshafts, especially the Exhaust camshafts, which are to be adjusted. If there is an electrical fault here, there is one Control of the camshaft position is no longer error-free possible, which also changes the idle speed possibly not to change the actual angle of the Camshaft position leads. Besides, none should electrical error in the detection of the brake application present, because in such a case the brake application cannot be recognized, why from safety-related reasons, an active increase in Idle speed should not take place then.

However, the idle speed increase is only activated when the deviation of the actual angle ϕ _actual from the target angle ϕ _{target of} the camshaft position exceeds a predefined threshold value SW. It is determined here whether the deviation has fundamentally exceeded this predetermined threshold value, that is to say is at least briefly higher than the predetermined threshold value. It is also checked whether the actual angle ϕ _actual runs away from the target angle ϕ _target . This is recognized by comparing the current actual angle with a filtered actual angle. A PT1 filter is suitable here as a filter. Alternatively, it can be checked whether the actual angle is greater than a predetermined limit angle. If one of the latter two signals is present, a check is carried out before a corresponding signal for activating the idle speed increase is issued to determine whether the deviation is present for longer than a predetermined time interval Δt. This has already been explained in more detail in relation to FIG. 1. If this is the case, the idle speed increase is activated. The idle speed increase is adapted as long as there is a deviation of the actual camshaft angle from the desired camshaft angle. The system learns how far the increase has to be made in order to adjust the actual camshaft angle back to the originally specified nominal camshaft angle. If such an error occurs later when you continue driving, a corresponding camshaft angle control can be carried out directly. If the deviation of the actual camshaft angle from the target camshaft angle does not last longer than the specifiable time period Δt, an idle speed reduction can be activated after a waiting period, provided the oil temperature is lower than at the idle adaptation start.

The adaptation also includes quantizing the values in order to mitigate a gradation of the values. Alternatively, one continuous speed increase. It will therefore asked whether the quantization is active. The goal of the adaptation or learning and possibly quantization is that Reaching a target idle speed. The adaptation is like this continued for a long time as there is no reset signal. On such is given if, as indicated in Figure 4b, at Engine start the oil temperature is less than a specifiable Oil temperature threshold or a limit value. To the To be able to precisely delimit the condition of the engine start and thereby knowing at what point the time from a sensor measured oil temperature is present and in which Temperature range, a start signal is awaited and additionally a further predetermined period of time, so that the Starting signal is delayed and that of the sensor measured oil temperature is present. Another reset condition is the interruption of the voltage supply as well as deleting the fault memory of the engine control unit, because then the release signal is no longer problem-free can be given, for example, electrical Error signals in the brake and the control of the Camshafts can be present.

If there is no reset signal, the adaptation of the Idle boost continued. However, is a Reset signal before, this leads to a restart of the system by re-querying a release signal and the Deviation of the actual camshaft angle from the specified one Camshaft set angle. Also the ongoing quantization is reset.

In addition to those described above and in the figures The exemplary embodiments shown can also be further are formed, each with an increase in Engine idle speed occurs when a Deviation of the actual angle of an adjustable camshaft is determined from a predetermined target angle. This also forms an oil pressure control adjust the idle oil pressure so that a steady one Engine running becomes possible. Exceeding the deviation of the Actual angle from the target angle of the camshaft with respect to a the predetermined threshold basically occurs if a compensation with the in the control device of adjustable camshaft provided actuator no longer is possible. By increasing the idle speed or by setting the idle oil pressure falls below the Target / actual angle deviation of the camshaft position again the predetermined threshold value, which increases driving comfort and the performance of the vehicle as well as exhaust and consumption values get back into an optimal area.

LIST OF REFERENCE NUMBERS

1

control unit

2

entrance

3

entrance

4

entrance

5

entrance

6

entrance

7

evaluation

9

engine

10

actuator

11

phase sensor

12

Cooling water temperature sensor

13

Oil temperature sensor

14

Tachometer

15

adjustable camshaft (NW)

SW

threshold

.delta.t

Period of time

t

time

ϕ _Should

target angle

ϕ _Is

actual angle

T _oil

Oil temperature signal

T _{cooling water}

Cooling water temperature signal

Claims (23)

1. System for eliminating the deviation of the actual angle of an adjustable, in particular continuously adjustable, camshaft (15) from a preset nominal angle (ϕ_nom) with an idling motor (9), and a control or regulating device for controlling or regulating the camshaft position, and a control unit for controlling the motor is provided, and a device (1) for increasing the idling revolutions of the motor (9) is provided which is activated on exceeding a predetermined value (SW) of the deviation of the actual angle (ϕ_act) of the camshaft (15) from the preset nominal angle (ϕ_nom), characterised in that the device (1) for increasing the idling revolutions offers an application-specific learned adaptive idling revolution.
2. System according to Claim 1, characterised in that the device for increasing the idling revolutions is and/or includes a control device (1) acting on the motor (9), in particular directly or via an additional control unit.
3. System according to Claim 1 or 2, characterised in that an angle detection device is provided for detecting the actual angle (ϕ_act) of the camshaft (15) and for giving an actual-angle signal.
4. System according to Claim 1, 2 or 3, characterised in that a device is provided for monitoring excesses of a preset threshold value (SW) of the nominal/actual angle deviation and for giving a signal.
5. System according to one of the above claims, characterised in that the control unit of the motor (9) and/or the device (1) for increasing the idling revolutions interrogates prior to activating increased idling revolution the presence of a motor system function signal and an admissible state-of-motor signal.
6. System according to one of the above claims, characterised in that the device (1) for increasing the idling revolutions causes a continuous increase in revolutions as of the revolution at which the deviation occurred.
7. System according to one of the above claims, characterised in that quantisation of the continuous revolutions takes place for producing defined idling revolutions.
8. System according to Claim 7, characterised in that the speed of the increase in idling revolutions is freely selectable between the quantised steps.
9. System according to one of the above claims, characterised in that, prior to activation of the active increase in idling revolutions, the absence of a signal of positive power contact between the motor and the wheels and/or the presence of a brake operating signal and/or a signal of the conditions of drive, braking system and/or motor from the system is interrogated.
10. System according to one of Claims 5 to 9, characterised in that the motor system function signal is given in the event of absence of a fault signal of the brake operation detection, of absence of a fault signal in the camshaft control, in the presence of a release signal of camshaft regulation, and an admissible state-of-motor signal is given in the presence of an idling revolution signal of the motor and a motor revolution signal below a preset revolution threshold, in particular 800 rev/min.
11. System according to one of the above claims, characterised in that an adaptation of the idling increase takes place when exceeding the deviation of the actual angle (ϕ_act) from the nominal angle (ϕ_nom) of the camshaft (15) by a preset value, in particular a value of 7° and/or when the actual angle moves away from the nominal angle and/or when the camshaft (15) is near its end stop and/or its late position, in particular at an angle of 5° and with the development of an error signal over a preset length of time (Δt), in particular longer than 0.1 s.
12. System according to Claim 11, characterised in that detection of movement of the actual angle (ϕ_act) away from the nominal angle (ϕ_nom) is offered by providing a filtered, in particular PT1-filtered, actual angle and comparison of the filtered actual angle with the respective actual angle.
13. System according to one of the above claims, characterised in that a learned increase in idling revolutions can be set back in the presence of an oil temperature signal at motor start which is below a preset and/or critical oil temperature threshold, in particular below 100°C and/or at interruption of the power supply and/or deletion of the error memory of the motor control unit.
14. System according to Claim 13, characterised in that a time delay of the end-of-start signal up to the presence of the oil temperature signal is provided in order to ensure safe detection of the set-back condition.
15. System according to one of the above claims, characterised in that in the presence of a revolution demand signal and the release signal the system initiates an idling nominal revolution value, and the device (1) for increasing the idling revolutions continuously increases the idling nominal revolution value with the preset revolution increasing speed, in particular at a speed of 20 rev/s.
16. System according to one of Claims 7 to 15, characterised in that means for producing defined revolutions are provided, in particular quantisation of the continuously increased idling nominal revolutions above a characteristic line.
17. System according to one of Claims 7 to 16, characterised in that means for avoiding an obviously stepped increase of the idling nominal revolutions after quantisation are provided, in particular a slowed down increase of the idling nominal revolutions over a ramp with a preset speed.
18. Combustion engine with a system according to one of the above claims.
19. Method for controlling an adjustable, in particular continuously adjustable, camshaft (15) of a combustion motor (9), which is provided with a control or regulating device for controlling or regulating the camshaft position, and on exceeding a preset value (SW) of the deviation of the actual angle (ϕ_act) of the camshaft (15) from a preset nominal angle (ϕ_nom) a device for increasing the deviation is activated, and the device (1) acts on a control unit for controlling the motor (9) in such a manner that the idling revolutions are increased, characterised in that an application-specific learned adaptive idling revolution is offered by a device for increasing the idling revolutions.
20. Control device for controlling the revolutions of a combustion engine (9) for use in a system according to one of Claims 1 to 17 and/or with a combustion engine (9) according to Claim 18 and/or in a method according to Claim 19, characterised in that provision is made for an input (2) for detection of control values of an adjustable camshaft (15), an input (3) for the signal of the cooling-water temperature of a cooling-water temperature indicator (12), an input (4) for the signal of the oil temperature of an oil-temperature indicator (13), an input (5) for inputting revolution values of a revolution indicators (14), a means (7) for evaluating, an input (6) for interrogating one or more additional signal sources, and at least one means (10) for acting on the idling revolutions and/or the idling oil pressure of the motor (9).
21. Control device according to Claim 20, characterised in that the signal source is the idling operational state.
22. Control device according to Claims 20 or 21, characterised in that the signal source is the drive pedal position and/or an idling signal, in particular of a motor management system.
23. Control device according to one of Claims 20 to 22, characterised in that the signal of a nominal angle indicator is a characteristic field.

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