DE10156510A1 - System to correct the deviation of an adjustable camshaft - Google Patents

Abstract

In a system for eliminating the deviation of the actual angle of an adjustable, in particular continuously adjustable camshaft (15) from a predeterminable setpoint angle (phi¶soll¶) when an engine (9) is idling, a control or regulating device for controlling or regulating the camshaft position and A control unit for engine control is provided, a device (1) for increasing the idle speed of the engine (9) is provided which, when a predeterminable value (SW) of the deviation of the actual angle (phi¶Ist¶) of the camshaft (15) from the predeterminable Target angle (phi¶soll¶) can be activated. In a method for controlling an adjustable, in particular continuously adjustable camshaft (15) of an internal combustion engine (9), which is provided with a control or regulating device for controlling or regulating the camshaft position, the deviation of the actual angle is exceeded when a predeterminable value (SW) is exceeded (phi¶Ist¶) the camshaft (15) from the predeterminable setpoint angle (phi¶Soll¶) activates a device (1) for eliminating the deviation and the device (1) acts on a control unit for controlling the engine (9) to the effect that that the idle speed is increased.

Description

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

In engines, in particular vehicle engines with camshafts, those are known which have a continuously adjustable camshaft. The adjustment is over an oil hydraulic system or an electric motor. The regulation of Camshaft position takes place via control valves that go from the control unit Motor control can be controlled. The camshaft is adjusted via the entire speed and load range. Deviations from the determined target positions the camshafts lead to a loss in driving comfort and performance and Worsening emissions and consumption.

When idling, the camshafts are in an overlap-free position, i. H. the The inlet is at the latest position and the outlet is at the earliest position Camshaft. Different positions of the camshaft lead to restless Engine running, which should however be avoided. For convenience and consumption reasons the idle speed should be as low as possible. However, when idling, it occurs at oil temperatures for example 80 ° C a very strong deviation of the camshafts from the target angle. This deviation usually takes place until the late stop of the exhaust actuator. at Older engines are only affected by this deviation from the target angle at higher oil temperatures observe. The deviation from the target angle when idling is explained by the fact that at hot oil this is a consequence of being thinner at higher temperatures oil, the low oil pressure when idling and the increasing friction torque of the camshafts appears to be the actuating force of the intake and exhaust actuators exceed.

To solve the general problem of idle adjustment in internal combustion engines some ways are shown in the prior art. For example, the DE 44 33 299 A1 a device and a method that make it possible Increase idle speed to ensure adequate engine lubrication ensure when the operating state of a so-called hot idling is reached in 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 Idle speed setpoint, which is determined by a control unit in comparison with an actual Speed is set by actuating an actuator. In the so-called Hot idling will set the speed setpoint to one compared to normal operation the higher value is switched when the oil pressure drops to low Values looming. This is recognized when the oil temperature rises above a Threshold is calculated. Switching takes place in hot idling by a provided switching means. The target idle speed in the hot idle state is in one separate storage element. A changeover signal is formed when the motor for a predetermined time at a speed above a limit speed and / or is operated in a high load state and, if appropriate, the Engine temperature and the intake air temperature above specified limit values lie.

DE 197 22 187 A1 describes a method for controlling an adjustable one Cam spread in an internal combustion engine in motor vehicles known. By means of a electronic control unit becomes a minimum from a basic map Pre-controlled cam spread. A smoothness monitoring unit determines whether at set minimum cam spread the internal combustion engine a quiet running limit exceeds. A spread adjustment unit increases the set one Cam spread as long as the smooth running limit is exceeded. Task of this The invention is to minimize fuel consumption and tax emissions. The Spread adjustment unit increases the set minimum cam spread restless engine running. A spread map for the specification of a setpoint of Cam spread is used for the most favorable environmental conditions, for example the lowest possible ambient pressure or for vehicle operation at higher altitudes designed.

DE 100 02 352 A1 describes a valve timing control system for one Internal combustion engine disclosed in which the controllability of the valve timing maintained and the combustion state of the internal combustion engine remain stable should. The valve timing control system includes u. a. a hydraulic actuator for Changing an operating angle of a cam of a camshaft to one Advance or delay valve timing in the internal combustion engine.

DE 197 24 709 A1 describes a method for determining an optimal one Idle speed of an internal combustion engine is known, by step by step Change in idle speed and comparison of old and new idle restlessness an optimal idle target speed is determined. There is an idle idle control due to fluctuations in speed. The idle speed is regulated to a ensure optimal operating behavior. Achievement is achieved during the process predetermined limits of idle speed determined. One finds each gradual increase or decrease in idle speed instead.

Various methods for controlling or monitoring the Idle speed of an internal combustion engine is known, in particular from the DE 195 34 844 A1, DE 40 16 099 A1 and DE 196 18 403 A1. In the DE 195 34 884 A1 is an idle idle control due to speed fluctuations thereby enables the gradient of the course of the actual speed of the Internal combustion engine determined and the manipulated variable for controlling the idle speed in Depending on the amount of the gradient is determined when the amount of Gradient exceeds a predetermined threshold. DE 40 16 099 A1 describes a device for idle speed control, in which a valve for Changing the amount of intake air of the internal combustion engine and u. a. a facility for Control the degree of opening of the valve according to the machine speed are provided. DE 196 18 403 A1 discloses a control device for the Idling speed using appropriate sensors. The smoothness will based on signals at least one arranged on the vehicle Acceleration sensor or one provided in the vehicle interior Noise sensor determined.

Another method for adapting the characteristic of an idle actuator is in the EP 0 399 016 B1. An adaptation of an idle control via a Intake air mass flow achieved. A method and an apparatus for Idle idle control is also disclosed in DE 44 43 652 A1. Starting from that A comparison between a setpoint and an actual value for the speed will be a Control deviation and manipulated variable are determined, with a pilot control and / or a Raising the setpoint depending on the speed is provided. By a Device for adjusting the course of movement of the gas exchange valves Internal combustion engine, wherein a camshaft has a controller that has a control signal generated for an actuator of an actuator for adjusting the camshaft Control signal corrected by the feedforward control. This serves a more comfortable Operation of the internal combustion engine even in non-stationary operation and with long dead times the device for adjusting the course of movement of the gas exchange valves, wherein these can be adjusted more quickly and the controller only has inaccuracies Pilot control compensated.

EP 0 808 997 A1 and EP 0 990 775 A1 provide further adjustment options for Known camshafts. There are first and second camshafts and means for Changing the rotational phase of the first and second camshafts is provided to a Change in the opening and closing timing of the intake valves. EP 0 990 775 A1 influences a three-dimensional cam Camshaft taken and an actuator is provided for changing the valve lift 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 speed of rotation Internal combustion engine are generated.

There is therefore no solution in the prior art that can cause the strong deviation of the adjustable camshafts, especially the exhaust camshafts, at idle Oil temperatures above a certain specific limit temperature from the actual one Target angle prevented. Such a deviation usually takes place until the late stop of the exhaust plate. With older motors, such a deviation from the target angle can only be observed at higher oil temperatures. This deviation when idling hot oil seems to be a consequence of being more fluid at higher temperatures oil, the low oil pressure when idling and the increasing friction torque of the camshafts that exceed the actuating force of the actuators. A possibility However, the prior art cannot be used to improve this problem remove.

The present invention is therefore based on the object of a system for rectification the deviation of the actual angle of the adjustable camshaft from a predefinable one To create the target angle when the engine is idling, taking a large deviation no longer occurs or is remedied when idling at higher oil temperatures.

This object is achieved by a system according to the preamble of claim 1 solved that a device for increasing the idle speed of the engine is provided is that when a predeterminable value of the deviation of the actual angle of the Camshaft can be activated from the predetermined target angle. Developments of the invention are defined in the dependent claims.

The invention is based on the finding that when the rotational speed is increased, the Deviation from target and actual angle is reduced. The is particularly advantageous Idle speed increased via the engine control. This gives the advantage a smoother engine running even at higher oil temperatures at idle, which the Driving comfort, but also the performance, emissions and the consumption of the vehicle be significantly improved. The moment a predefinable threshold value of the Angle deviation is exceeded, the system activates the lifting device the engine idling speed. In doing so, the predeterminable limit is exceeded Limit of oil temperature checked to include a slowly adjustable camshaft not to cause the cold engine to activate an idle speed increase. The The idle speed is preferably raised via the control unit Motor control. The system thus serves to correct the deviation of the actual angle from the nominal angle of the camshaft by increasing the idle speed. Because the actual angle of the Camshaft position queried, compared with the specifiable setpoint and at Deviation an adjustment of the camshaft position by increasing idle speed is carried out in order to set the actual camshaft angle back to the target angle, the camshaft position is thus constantly corrected so that a Deviation of the actual angle from the target angle not or only in an approved one Tolerance range occurs.

The system according to the invention can be used in any position of the camshaft , so even with maximum overlap and with no overlap Position.

A device for rotating a camshaft relative to the crankshaft in one Motor vehicle internal combustion engine is known for example from DE 43 40 614 C2. Here, however, an electrical control signal to be calculated is used adjustable actuator for turning the camshaft relative to the crankshaft adjusted. The control signal to be calculated is a basic control signal, the assigned to every difference between the actual position and the target position of the camshaft is one of the oil temperature and the speed of the internal combustion engine dependent correction value and calculated from an adaptation value. The twisting of the The camshaft is therefore not dependent on the idling speed of the engine adjusted or the deviation of the actual angle from the target angle of the camshaft position used for adaptive idle boost. The twist relates directly to the control of the camshaft without further incorporation of the idling speed of the Motors in the control system.

Adjustable camshafts or a camshaft position control is in the state of the Technology also to control the idle speed learning of an engine with internal combustion used, as disclosed in DE 196 47 182 C2 or for Control of fuel injection, as described in DE 196 35 042 C2. The Taking the adjustable camshaft into account when controlling the Fuel injection according to DE 196 35 042 C2 also includes the application of a Pressure force on the camshaft and changing the rotation phase of the camshaft with respect to the synchronous pulley or crankshaft to a maximum Advance angle of a maximum lag angle, so that the closing control is moved forward with respect to the intake valves. In the opposite case, the Phase of rotation of the camshaft with respect to the synchronous pulley to maximum Lag angle changed from maximum lead angle so that the opening timing or the opening time control with regard to the inlet valves is delayed. The learning value is calculated based on the ratio of real valve characteristics (actual Cam angle) to the valve characteristics for the engine in the fully heated state compensated. Here, too, no reference is made to the idling speed of the Engine because the fuel injection of the engine is to be controlled.

Preferably, according to the present invention, the device for lifting the Idle speed a control unit and / or acts on the engine, especially directly or via its control unit. This is not only the fastest, but also given the most direct way of influencing the idling speed.

The speed can preferably be increased continuously as soon as a deviation the actual angle from the target angle has occurred. Preferably, the device for Increasing the idle speed a continuous speed increase from the speed, at which the deviation occurred. This increases the idle speed from a determinable value that is at least close to the desired value Idle speed. So there is no need to adjust from zero, what with a longer settling time would be connected.

A is preferably used to generate defined idling speeds Quantization of continuous speeds. This makes it possible to only define Allow idle speeds. The speed of the idle speed increase there is preferably a free choice between the quantized levels. As a result, a Adaptation or adaptation to the respective application or the respective Engine type. Alternatively, the speed can be increased continuously. In particular, an optional application-specific configurability of the Systems are provided.

For detecting the actual angle of the camshaft and emitting an actual angle signal ist preferably an angle detection device is provided. It is also preferred means for monitoring the exceeding of a predeterminable threshold value the target angle / actual angle deviation and for emitting a signal. The angle detection device and the device for Monitoring the exceeding of a predefinable threshold value can be coupled to one another, so that the facility to monitor the exceeding of the predeterminable Threshold value can query the current actual angle directly.

It proves to be particularly advantageous that the device for lifting the Idle speed preferably an application-specific adaptive learning Delivers idle speed. Thus, the idle speed does not have to be fixed above the oil temperature filed, which would result in the worst engine in new condition the idle speed specifies what a for all engines over the entire runtime minimum speed would mean z. B. of 750 rpm. For comfort and However, for reasons of consumption, the idle speed should be as low as possible, e.g. B. 560 rpm be. In this context, learning idling speed means that the state of the camshaft from the idle speed currently approached is judged. In most cases, this will be the last idle speed approached his. If the idle speed is increased during a so-called learning ban, for example by switching on an air conditioning compressor, etc., when learning is enabled by learned from this higher speed, because lower speeds are even worse with respect to the camshaft deviation than the higher speed. The engine comes from higher speeds to idle again, he usually goes back to last learned idle speed. Then there is a camshaft deviation found, the idle speed increases until either leave the learning state or the maximum permissible idling speed limit has been reached. However, will not If the camshaft deviation is found, there is no activity if none Idle speed increase has occurred. Alternatively, under adjustable Boundary conditions initiate a reset attempt if there is a speed increase. Learning backwards is possible in much the same way as that Learning an increased speed. The oil temperature drops and has been there for one no error before the adjustable time, the relearning is preferably started.

This is preferred before activating the active idle speed increase Absence of a signal of the motor locking with the wheels and / or the presence of a brake actuation signal is queried by the system. at The absence of such a signal is the presence of idle accepted. If the accelerator pedal is pressed, the engine is not in the state of the Idling. Thus, when the accelerator pedal is actuated, the idle speed is basically increased not possible. The presence of the brake (pedal) actuation signal for the activation of the Idle speed increase can be configured advantageously and leads to increased Safety. If there is a detected brake error, the function can be deactivated Security reasons should preferably be blocked. Because with a vehicle Automatic gearbox the driving force transmitted by the gearbox at engine speed increases, the vehicle standing on a slope could shift with a gear engaged start moving without brake application. The activation of the Idle speed increase can therefore preferably be configured in a user-specific manner occur when a brake actuation signal is present, regardless of the presence or there is no adhesion of the motor to the wheels - not gear "N" or "P" for an automatic transmission - regardless of the brake application. The Accelerator pedal actuation can advantageously be excluded by querying idling become. In principle, an adaptation according to the invention can also be carried out in one Range take place in which the speed is greater than that due to the accelerator pedal being pressed Idle speed is too low to hold the camshaft position. On however, such a case is relatively unlikely.

Preferably, the control unit of the engine and / or the device for lifting the Idle speed before activating the idle boost the presence of a Engine system function signal and an allowable engine status signal in the form of a Release signals from. This ensures that there is no fault in the motor system and the engine condition is set to act on the idle speed is certainly possible.

A motor system function signal is preferably used in the absence of an error signal in the brake actuation detection, in the absence of an error signal in the Camshaft control, in the presence of an enable signal from Camshaft control issued. An allowable engine status signal is preferred when there is an engine idle signal and an engine speed signal below a predefinable speed threshold, in particular 800 rev / min. Since the Idling speed increase is preferred for safety reasons when none There is a fault in the system and the engine is in a predefinable state, the individual parameters of the system or the motor function and its Condition queried. To ensure that a brake application signal is actually is present, a query is provided to the effect that no electrical error in the There is detection of brake actuation. To avoid that the target angle / Actual angle deviation of the camshaft is present due to a system error advantageously provided a query that no electrical error in the control of the Camshafts, especially exhaust camshafts, are present. To the To be able to influence camshaft position is also preferably a query an approved camshaft control included in the system. One for them Idle speed increase suitable engine condition is idling and Engine speeds that are below a specifiable speed threshold. A Speed threshold of 800 rpm is only given as an example and can can be set specifically for the application.

The idle boost is preferably adapted when the Deviation of the actual angle from the nominal angle of the camshaft by a predeterminable value, in particular a value of 7 ° and when the actual angle runs away from the target angle and / or when the camshaft is near its end stop and / or Late position, especially at an angle of 5 ° and when an error signal occurs over a predefinable period of time, in particular longer than 0.1 seconds. The The system thus advantageously has a query regarding the adaptation of the Idle boost to determine whether there is actually a target / actual angle deviation of the Camshaft angle is present, in particular is permanent. To a value for one To define such a deviation, a threshold value is preferably defined, which in Dependence on the respective application is chosen and in a particular preferred embodiment can be 7 °. It is in other embodiments however, any other angle value is also possible. Preferably at the same time also queried whether the actual angle runs away from the target angle, i.e. the deviation of the Angle from each other increases steadily. This makes the long-term advantageous Queried for a deviation. A detection of the running away of the actual angle of the target angle can, for example, by providing a filtered actual angle and Comparison of the filtered actual angle with the current actual angle. On a suitable filter is, for example, a PT1 element. The presence of a target angle / Actual angle deviation of the camshaft angle can also be determined by that the camshaft is close to its end stop, i.e. the so-called late position, located. Here too, a value for the end stop detection or Predetermined late position detection. In a special embodiment, this angle for example, assume a value of 5 °. In other applications this can Value can be varied. An inquiry is preferably provided at the same time that an error identified from the above conditions lasts longer than a specific one Time period is present, i.e. an error signal over a predefinable time period occurs. This also recognizes whether the target angle / actual angle deviation of the Camshaft angle is a unique phenomenon or a permanent condition that too would fix.

A learned idle speed increase can preferably be reset, particularly preferred in the presence of an oil temperature signal when the engine starts, the smaller is as a predeterminable and / or critical oil temperature threshold, e.g. B. less than 100 ° C and / or if the power supply is interrupted and / or the Fault memory of the engine control unit. When the external conditions change it has been shown to be advantageous by the system for the previous outside Conditions learned to change idle speed increase since the learned Idle speed increase may not be appropriate for the new environmental conditions is appropriate and relearning on the basis of the new conditions is more difficult appears as a complete reset and restart of the learning process. A Query as to whether the oil temperature is lower than the critical one when the engine is started Is oil temperature threshold, is preferably linked to another query that This means that there is a time delay between the start signal and the presence of the Oil temperature signal is carried out in order to ensure that the reset condition can be reliably recognized guarantee. The critical oil temperature threshold can be application-specific to get voted. An interruption in the voltage supply leads preferably also to reset the system or at least the device for Raising the engine idle speed. When the power supply is interrupted can otherwise cause malfunctions and errors in the Idle speed increase, especially in relation to the learned values, occur that it is safer to switch off the learned one if the power supply is interrupted Reset speed increase completely. Since, for safety reasons, error signals too are queried by the engine, the will be advantageous if the fault memory is deleted Engine control unit also reset the learned speed increase.

The idle speed increase takes place via all those described above Conditions preferably according to the following scheme: If a The system preferably initializes the speed request signal and the release signal a target idle speed value and the means for increasing the idle speed preferably raises 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. But they are also any other values possible. Means for generating defined speeds are preferred provided, in particular a quantization of the continuously raised Target idling speed via a characteristic curve. This allows the idle speed only assume defined speeds, for example from the noise can be advantageous.

Preference is also given to means for avoiding a conspicuously staged ramp-up Idle speed is provided after the quantization, especially one slowed increase of the idle speed via a ramp with a predetermined speed. This will smooth the quantized values the idle speed made, resulting in better driving comfort and leads to more pleasant noise.

The object underlying the invention is also achieved by a method for Control of an adjustable, in particular continuously adjustable camshaft an internal combustion engine with a control or regulating device for controlling or control of the camshaft position is provided, with being exceeded a predeterminable value of the deviation of the actual angle of the camshaft from Predeterminable target angle, the device for eliminating the deviation is activated and the device being directed to a control unit for controlling the engine Acts that the idle speed is increased. In addition, the task is marked by a Method for regulating idle oil pressure using an adjustable, in particular continuously adjustable camshaft of an internal combustion engine, the with a control or regulating device for controlling or regulating the Camshaft position is provided, which, when a predetermined value is exceeded Deviation of the actual angle of the camshaft from the predetermined target angle the device is activated to correct the deviation and the device is set to a Control unit for controlling the engine acts so that the idle oil pressure is increased. The position of the camshaft is an advantageous indicator of the oil pressure. By a control unit for controlling the speed of an internal combustion engine, in particular for use in the aforementioned system and / or in one of the above method, the object is achieved in that an input to Acquisition of control values of an adjustable camshaft, an input for the signal of the Cooling water temperature of a cooling water temperature sensor, an input for the signal the oil temperature of an oil temperature sender, an input for entering Speed values of a speed sensor, a means for evaluation, an input to Queries from one or more further signal sources and at least one means for Action on the idle speed and / or the idle oil pressure of the engine provided are. As a result, the provision of only one control unit Advantages of the invention can be achieved.

In the control unit, it is preferred that the signal source is the idle operating state and / or the accelerator pedal position and / or an idle signal, in particular one Engine management system is. The signal from the setpoint generator can preferably be a Map. As a result, there is greater variability and therefore better Adaptation to changing operating conditions possible.

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

Fig. 1 diagrams an idle speed increase in deviation of the target angle of the exhaust camshaft using a system according to the invention,

Fig. 2 is a schematic view of a control device according to the invention as a means for raising the idle speed and / or increasing the idling oil pressure of an internal combustion engine,

Fig. 3 is a flow chart illustrating the increase in the idle speed and / or increasing the idling oil pressure using a system according to the invention or a control device of the invention according to Fig. 2, and

Fig. 4a, b two-part flow diagram with detailed specification of individual steps in the query according to the invention increase in the idle speed and / or the idling oil pressure of an internal combustion engine.

Fig. 1 shows two diagrams to illustrate the rotational speed curve for deviation of the camshaft position an adjustable camshaft from a predeterminable desired angle. In this exemplary embodiment, this is constant at 0 °. The actual angle initially rises slightly over time, then rises sharply after a threshold value SW is exceeded. The designation of the vertical axis of the first diagram indicating the camshaft position in FIG. 1, ° AS, means deviation of the nominal angle of the camshaft. The speed shown in the second diagram in revolutions per minute over time is at a camshaft angle of minus 20 ° at 560 rpm, which represents an idling speed with smooth engine running and thus good comfort and low consumption. First, the deviation of the camshaft position has no consequences for the idle speed. After the threshold value of the deviation of the actual angle of the adjustable camshaft from the predetermined target angle has been exceeded, the system according to the invention for increasing the idling speed determines that this threshold value has been exceeded and that the actual angle continuously runs to an unfavorable position. In addition, he receives information, in particular from a limit switch, as to whether the camshaft position is close to its end stop, that is to say the late position. In the embodiment shown in Fig. 1, the camshaft position almost reaches the end stop of 22 °. In addition, a query is made as to whether the deviation of the target angle from the actual angle is greater than the predefinable threshold value. This can be answered in the affirmative after the threshold value SW has been exceeded and the deviation has risen sharply over time. The deviation of the setpoint from the actual value is so large when the threshold value is exceeded that it is still checked whether this error persists longer than a predetermined period of time Δt. This is also the case in the exemplary embodiment according to FIG. 1. The time period Δt can, for example, be specified as 0.1 seconds. It can assume other values depending on the engine and application.

As can also be seen in the exemplary embodiment in FIG. 1, after the time span Δt has been exceeded, the idling speed is increased in quantized steps, first to a predeterminable speed of 650 rpm and subsequently to a predetermined speed of 700 rpm. The transition to the higher speed level takes place continuously via a ramp in order not to negatively affect driving comfort. The idle speed is increased from the speed at which the deviation occurred, i.e. in the application from 560 rpm. The speed of the idle speed increase between the quantized stages, i.e. the 650 and the 700 rpm, can be freely set. A continuous increase in idle speed is also possible. The respective type of increase can be freely adjusted depending on the application.

The idle speed is increased until the camshaft position returns to originally specified target value is reached, that is to one in the case shown Angle drops from 0 °. Here again the threshold value SW is exceeded, now however, in the direction of the predetermined target angle. This is done by the system also queried or recognized, whereby the continuous lifting of the Idle speed set and the idle speed at the meantime reached Value, here 700 rpm, is maintained.

When the idle speed is increased, the idle oil pressure is also increased, so that the exhaust camshaft, which previously deviates greatly from its target angle, returns to the target target position that was actually aimed for. Simply by adjusting the camshaft position without increasing the idle speed or idle oil pressure, no compensation is possible with the actuator provided for the control or control device for the camshaft position. This requires the additional provision of at least one control device according to the invention, as shown in particular in FIG. 2, which can also supplement the camshaft position control or regulating device, for example.

According to FIG. 2, a control device 1 an input 2 for detecting the control values of an adjustable camshaft, in particular by a phase sensor 11, an input 3 for the signal from the cooling water temperature, an inlet 4 for the signal of the oil temperature, an inlet 5 for inputting speed values and an input 6 for detecting signals from one or more further signal sources. The control unit receives and processes signals such as the phase sensor 11 of the adjustable camshaft 15 , a speed sensor 14 of the engine, a cooling water temperature sensor 12 and an oil temperature sensor 13 . A device 7 for evaluation contained in the control unit evaluates the prepared values and acts on actuators 10 which cause an idle speed increase of an engine 9 , such as. B. an idle speed control device. Control unit 1 can implement the processed and evaluated values via the actuators throttle valve, ignition, injection (for idle speed control) and camshaft control valves.

For example, the accelerator pedal position, an idle signal and the idle operating state can be queried as a signal source for the input of further signals via the input 6 of the control device 1 . The functions of an engine management system can run in one or more control units, the use of only one control unit proving to be less expensive. Speed sensor 14 for recording and outputting the idle speed values, cooling water temperature sensor 12 , oil temperature sensor 13 and phase sensor 11 of the adjustable camshaft 15 are only indicated in FIG. 2. Instead of a single setpoint angle, a setpoint angle map is preferably output.

Fig. 3 shows a flow chart of the operation of a system according to the invention for increasing the idle speed of an internal combustion engine. In a first step, a query is made continuously as to whether there is a deviation of the actual angle from the target angle that is greater than a predetermined threshold value SW. If the deviation does not exceed the threshold, the query continues. If the deviation exceeds the specified threshold, an enable signal is queried. If this is also the case, the idle speed increase is activated. However, the release signal is only available when a positive engine function signal and a permissible engine status signal are present. In a fourth step, an idle speed value is initialized and then in a fifth step it is continuously raised at a predetermined speed increase speed. In a sixth step, the continuously increased speed is quantized using a characteristic curve. As a result, only defined idle target speeds are set. In a seventh step, the nominal idle speed is increased slowly via a ramp at a speed that can also be specified. This prevents a conspicuously step-up. In an eighth and final step, the target idling speed is maintained and output to an engine control unit. The raising of the idling setpoint speed is ended when there is no longer any deviation of the actual angle from the setpoint angle of the camshaft position that is greater than the predetermined threshold value SW.

The enable signal is given when both an engine system function signal and an allowable engine status signal are present. Which factors form these signals can be better seen in FIGS. 4a and b, which together represent a query scheme. Here again, a process is shown in which the factors of forming an enable signal and determining a deviation of the actual angle from the desired angle of the camshaft, exceeding a predetermined threshold value of this deviation and resetting the control device or system for increasing the idle speed are reproduced. According to FIG. 4a, for the presence of the release signal and thus for the activation of the idle speed increase, it is necessary that either no gear step (example automatic transmission) is engaged. B. can be determined by querying the gear selector lever, regardless of the operation of the brake pedal, or the brake pedal is operated, which, for. B. can be queried by a sensor in the area of the brake pedal, regardless of whether or not a gear is engaged. The correct status of the speed step and brake is therefore queried. The engine status signal, as is also indicated in FIG. 3, is formed in that the engine is idling, that is to say an idling signal is present and that the engine speed is below a predetermined speed threshold. The activity of the idle speed control is also queried. The engine system function signal is formed by the presence of an enable signal from the camshaft control, so that an adjustment of the camshaft is possible. In addition, there should be no electrical error in the control of the camshafts, in particular the exhaust camshafts, which are to be adjusted. If there is an electrical fault here, it is no longer possible to control the camshaft position without errors, so that a change in the idling speed may not lead to a change in the actual angle of the camshaft position. In addition, there should be no electrical error in the detection of the brake actuation, since in such a case the brake actuation cannot be recognized, which is why an active increase in the idle speed should not take place for safety reasons.

However, the idling 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 predetermined 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 desired 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 when the idle adaptation starts.

The adaptation also includes quantizing the values to alleviate a gradation of the values. Alternatively, the speed can be increased continuously. It is therefore asked whether the quantization is active. The aim of the adaptation or learning and, if necessary, the quantization is to achieve a target idling speed. The adaptation continues as long as there is no reset signal. Such is given if, as indicated in FIG. 4b, when the engine starts, the oil temperature is less than a predeterminable oil temperature threshold or a limit value. In order to be able to precisely delimit the condition of the engine start and thereby to know at what point in time the oil temperature measured by a sensor is present and in which temperature range, a start signal is waited for and a further predetermined period of time so that the start signal is delayed and the oil temperature measured by the sensor is present. A further reset condition is the interruption of the voltage supply as well as the deletion of the fault memory of the engine control unit, since then the release signal can no longer be issued without any problems, since, for example, electrical fault signals can be present when the brake and the camshafts are actuated.

If there is no reset signal, the adaptation of the idle boost is continued. Lies however, a reset signal before, this leads to a restart of the system under renewed Query of a release signal and the deviation of the actual camshaft angle from the specified target camshaft angle. The ongoing quantization will also reset.

In addition to the exemplary embodiments described above and shown in the figures, further examples can be formed, each of which increases the idling speed via the engine if a deviation of the actual angle of an adjustable camshaft from a predetermined target angle is determined. This also forms an oil pressure control in order to set the idle oil pressure so that smooth engine running is possible. Exceeding the deviation of the actual angle from the target angle of the camshaft with respect to a predefined threshold value basically occurs when compensation with the actuator provided in the control device of the adjustable camshaft is no longer possible. By increasing the idle speed or by adjusting the idle oil pressure, the target / actual angle deviation of the camshaft position falls below the predetermined threshold again, whereby the driving comfort and the performance of the vehicle, as well as exhaust gas and fuel consumption values, return to an optimal range. List of Reference Numerals 1 Control unit
2 entrance
3 entrance
4 entrance
5 entrance
6 entrance
7 evaluation device
9 engine
10 actuator
11 phase generator
12 cooling water temperature sender
13 oil temperature sender
14 speed sensor
15 adjustable camshaft (NW)
SW threshold
Δt time span
t time
j _Target angle
φ is _actual angle
T _{oil oil} temperature signal
T cooling water cooling water temperature _signal

Claims (25)

1. System for eliminating the deviation of the actual angle of an adjustable, in particular continuously adjustable camshaft ( 15 ) from a predeterminable _target angle (φ _target ) when an engine ( 9 ) is idling, a control or regulating device for controlling or regulating the camshaft position and a control unit is provided for engine control, characterized in that a device ( 1 ) is provided for increasing the idle speed of the engine ( 9 ) which, when a predeterminable value (SW) of the deviation of the actual angle (φ _actual ) of the camshaft ( 15 ) from the predeterminable Target angle (φ _target ) can be activated. 2. System according to claim 1, characterized in that the device for increasing the idle speed is a control unit ( 1 ) and / or comprises and acts on the engine ( 9 ), in particular directly or via an additional control unit. 3. System according to claim 1 or 2, characterized in that an angle detection device for detecting the actual angle (φ _actual ) of the camshaft ( 15 ) and emitting an actual angle signal is provided. 4. System according to claim 1, 2 or 3, characterized in that a device for monitoring the exceeding of a predeterminable Threshold value (SW) of the target angle / actual angle deviation and for delivering a Signal is provided. 5. System according to any one of the preceding claims, characterized in that the device ( 1 ) for increasing the idle speed delivers an application-specific learning adaptive idle speed. 6. System according to any one of the preceding claims, characterized in that the control unit of the engine ( 9 ) and / or the device ( 1 ) for increasing the idle speed before activating the idle speed increase queries the presence of an engine system function signal and a permissible engine state signal. 7. System according to any one of the preceding claims, characterized in that the device ( 1 ) for increasing the idle speed causes a continuous speed increase from the speed at which the deviation has occurred. 8. System according to one of the preceding claims, characterized in that a quantization of the to generate defined idle speeds continuous speeds. 9. System according to claim 8, characterized in that the speed of the idle speed increase between the quantized Levels are freely selectable. 10. System according to one of the preceding claims, characterized in that before activating the active idle speed increase the absence of a Signal of the adhesion of the motor to the wheels and / or the presence a brake actuation signal is queried by the system. 11. System according to one of claims 6 to 10, characterized in that the engine system function signal in the absence of an error signal in the Brake actuation detection, in the absence of an error signal in the Camshaft control, in the presence of an enable signal from Camshaft control is given and that an allowable Engine status signal when there is an idle signal from the engine and one Engine speed signal below a predefinable speed threshold, in particular 800 rpm is delivered. 12. System according to one of the preceding claims, characterized in that an adaptation of the idle boost takes place when the deviation of the actual angle (φ _actual ) from the target angle (φ _target ) of the camshaft ( 15 ) by a predeterminable value, in particular a value of 7 ° and / or when the actual angle runs away from the setpoint angle and / or when the camshaft ( 15 ) is close to its end stop and / or its late position, in particular at an angle of 5 ° and when an error signal occurs over a predefinable time period (Δt), in particular longer than 0.1 s. 13. System according to claim 12, characterized in that a detection of the running away of the actual angle (φ _actual ) from the target angle (φ _target ) is provided by providing a filtered, in particular PT1-filtered actual angle and comparison of the filtered actual angle with the current actual angle. 14. System according to one of the preceding claims, characterized in that a learned idle speed increase can be reset if one is present Oil temperature signal at engine start, which is smaller than a predeterminable and / or critical oil temperature threshold, in particular less than 100 ° C, and / or at Interruption of the power supply and / or deletion of the fault memory the engine control unit. 15. System according to claim 14, characterized in that a time delay of the start signal until the presence of the Oil temperature signal is provided to ensure that the Ensure reset condition. 16. System according to one of the preceding claims, characterized in that when a speed request signal and the release signal are present, the system initializes an idle speed value and the device ( 1 ) for increasing the idle speed continuously increases the idle speed value at the predefinable speed increase speed, in particular at a speed of 20 U / s. 17. System according to one of claims 8 to 16, characterized in that Means for generating defined speeds are provided, in particular a quantization of the continuously raised idle speed over a Curve. 18. System according to one of claims 8 to 17, characterized in that Means to avoid a conspicuously gradual ramp-up of the Idle target speed are provided after the quantization, in particular a slowed increase of the idle speed via a ramp with a predetermined speed. 19. Internal combustion engine with a system according to one of the preceding claims. 20. Method for controlling an adjustable, in particular continuously adjustable camshaft ( 15 ) of an internal combustion engine ( 9 ), which is provided with a control or regulating device for controlling or regulating the camshaft position, the deviation of the actual angle being exceeded when a predeterminable value (SW) is exceeded (φ _actual ) of the camshaft ( 15 ) from the predeterminable setpoint angle (φ _setpoint ) a device ( 1 ) for eliminating the deviation is activated and the device ( 1 ) acts on a control unit for controlling the engine ( 9 ) in such a way that the idling speed is increased. 21. Method for regulating the idling oil pressure using an adjustable, in particular continuously adjustable camshaft ( 15 ) of an internal combustion engine ( 9 ), which is provided with a control or regulating device for controlling or regulating the camshaft position, with a predeterminable value (SW) being exceeded. the deviation of the actual angle (φ _actual ) of the camshaft ( 15 ) from the predetermined _target angle (φ _target ), a device ( 1 ) for eliminating the deviation is activated and the device ( 1 ) acts on a control unit for controlling the engine ( 9 ) that the idle oil pressure is increased. 22. Control device for controlling the speed of an internal combustion engine ( 9 ), in particular for use in a system according to one of claims 1 to 18 and / or with an internal combustion engine ( 9 ) according to claim 19 and / or in a method according to claim 20 or 21, characterized in that an input ( 2 ) for detecting control values of an adjustable camshaft ( 15 ), an input ( 3 ) for the signal of the cooling water temperature of a cooling water temperature sensor ( 12 ), an input ( 4 ) for the signal of the oil temperature of an oil temperature sensor ( 13 ), an input ( 5 ) for entering speed values of a speed sensor ( 14 ), a means ( 7 ) for evaluating, an input ( 6 ) for querying one or more further signal sources and at least one means ( 10 ) for acting on the idling speed and / or the idle oil pressure of the engine ( 9 ) are provided. 23. Control device according to claim 22, characterized in that Signal source is the idle operating state. 24. Control device according to claim 22 or 23, characterized in that Signal source, the accelerator pedal position and / or an idle signal in particular of an engine management system. 25. Control device according to one of claims 22 to 24, characterized in that the signal from a setpoint encoder is a map.