DE102007037296B3 - Electrically movable actuator's position controlling method for internal combustion engine of motor vehicle, involves developing controller to enable actuator for performing controlled periodic transfer movement at target position value - Google Patents

Abstract

The method involves determining a difference of an actual position value (IW) and a target position value (SW) of an electrically movable actuator (A). An auxiliary signal (ZS) is formed in such a manner that a controller provides an output variable (RAG) in a form of control signal (SS) to the actuator based on the difference and the auxiliary signal. The controller is developed in such a manner that the actuator performs a temporally controlled periodic transfer movement at the target position value, where the transfer movement represents periodic vibration at the target position value.

Description

The The invention relates to a method for controlling the position of a electrically movable actuator for an internal combustion engine as well a regulator device which is designed such that it Perform the procedure can.

modern Internal combustion engines have one size Number of electrically movable actuators. These include, but are not limited to, electromagnetic, piezoelectric and electromechanical actuators for valves for controlling and metering liquid or gas streams. When Examples would be here Intake and exhaust valves, Injectors for the Fuel, tank ventilation valves, Exhaust gas recirculation valves, Throttle valves and quantity or pressure control valves for high-pressure injection to call. Depending on the application, the actuator must be very fast and, in terms of location, extremely precisely controlled become. Often Even very small adjustment paths can be realized. However, you can with the actuators a static friction occur, which is a quick adjustment makes it difficult to small travel paths, as to break the actuator increased Measure Excitation energy is required. However, the actuator is an excess of electrical Supplied with energy, it can overshoot of the actuator over the actual nominal position come. This behavior is, however undesirable in a time-critical and high-precision position control.

Out DE 197 39 827 B4 and DE 691 23 829 T2 Control methods for electric actuators are known in which an additional signal is supplied to the controller output to compensate for static friction.

adversely However, in these procedures is that changes in the positioning behavior of the actuator, for example due to temperature influences, from Regulator disregarded stay.

It is therefore the object of the present invention, a method and a device for controlling the position of an electric movable actuator for to provide an internal combustion engine, which a higher precision at allow the position control.

These The object is achieved by the method and the regulator device according to the independent claims. The dependent claims show advantageous embodiments of the invention.

at a control method for an electrically movable actuator according to claim 1 is an actual position value measured, which is representative is for the actual Position of the actuator, and a position setpoint for the actuator determined. Furthermore, a difference between the position actual value and the position reference value determined and the difference an additional signal in the form of a periodic Vibration imparted. The controller is the difference superimposed with the additional signal supplied as a controller input variable. The Additional signal is designed such that the controller based on the controller deviation and the additional signal a controller output in the form an actuating signal for forms the actuator, which is such that the actuator a Regulated, recurring deviation movement from the position setpoint performs.

By the controlled deviation movement of the actuator will be an adhesion of the Actuator safely avoided due to stiction, creating a new Target position much faster even with very small adjustment paths and above all, more precise can be adjusted. Since an increased energy input to the initial "break" (overcoming the static friction) of the actuator is no longer necessary, can overshoot of the actuator can be prevented. According to the additional signal is the Controller supplied as a controller input. This brings the advantage with it, that carried out by the actuator deviation movement is regulated. Unlike an execution, in the pitched such an additional signal of a controller output is, the additional signal acts here not as a disturbance, but more or less as an additional Setpoint. This can be an undesirable Controller behavior can be avoided. Due to the controlled deviation movement There is also the advantage that disturbance variables which have an influence on the actuator behavior (such as temperature changes or age-related binding) be automatically corrected. The deviations made by the actuator therefore run independently from such external influences in the Essentially always the same. This results in greater reliability and operational safety of the actuator.

In The embodiment of the method according to claim 2 is the additional signal formed such that the deviation movement is a periodic oscillation represents the position setpoint.

By the continuous, periodic oscillation around the position setpoint ensures that the actuator with very small amplitude order the actual position setpoint oscillates and thus constantly in Movement is. Through this constant movement Adhesion of the actuator is reliably avoided at the desired position. If the actuator is a metering valve Fluid streams, can be minimized influencing the amount of fluid to be dosed be that deviation motion with very low amplitude and accordingly high frequency performed becomes.

In the Design of the method according to claim 3, the controller output variable in the form of a pulse width-modulated actuating signal, wherein the deviation movement caused by corresponding variation of the duty cycle becomes.

Especially Electromagnetic or electromechanical actuators can be by means of a pulse-width-modulated control signal in a simple manner regulate. The time-recurring deviation movement is at this Embodiment by a pulse width-modulated fundamental signal superimposed Generates vibration, resulting in a variation of the duty cycle.

According to one Embodiment of the method according to claim 4, the additional signal rectangular, triangular, or sinusoidal be. The different signal forms result in a higher flexibility, which the signal shape to different circumstances and embodiments of the actuator can be adjusted.

A Regulator device according to the claim FIG. 5 is designed to implement the method according to the claim 1 can. In terms of the benefits will be on the designs refer to claim 1. These apply analogously here.

in the Below, the invention will be described with reference to an embodiment with reference to the attached Figures closer explained.

In the figures are:

1 a schematic representation of an internal combustion engine;

2 a schematic representation of a valve;

3 a schematic representation of the structure of a regulator device.

In 1 is an internal combustion engine 1 shown schematically. For reasons of clarity, the representation is simplified.

The internal combustion engine 1 includes at least one cylinder 2 and one in the cylinder 2 reciprocating pistons 3 ,

The internal combustion engine 1 further includes an intake passage in the downstream of a suction port 4 an air mass sensor 5 , a throttle 6 and a suction tube 7 are arranged. The intake tract opens into a through the cylinder 2 and the piston 3 limited combustion chamber 30 , The fresh air needed for combustion is transferred via the intake tract into the combustion chamber 30 initiated, wherein the fresh air supply by opening and closing a controllable inlet valve 8th is controlled.

In the internal combustion engine shown here 1 it is an internal combustion engine 1 with direct fuel injection, in which the fuel required for combustion via an injection valve 9 directly into the combustion chamber 30 is injected. At the injection valve 9 For example, it is an electromagnetic, piezoelectric or electromechanical injection valve. To trigger the combustion, one also serves in the combustion chamber 30 protruding spark plug 10 , The combustion gases are via a controllable exhaust valve 11 in an exhaust tract of the internal combustion engine 1 discharged and by means of an arranged there exhaust gas catalyst 12 cleaned. At the inlet valve 8th and the exhaust valve 11 These are electromagnetically or piezoelectrically actuated valves whose stroke and timing are individually adjustable.

The power transmission to a drive train of a motor vehicle (not shown) via a with the piston 3 coupled crankshaft 13 , The internal combustion engine 1 also has a coolant temperature sensor 14 , a speed sensor 15 for detecting the rotational speed of the crankshaft 13 and a lambda sensor 16 for measuring the exhaust gas composition.

The internal combustion engine 1 continue to be a fuel tank 17 and a fuel pump disposed therein 18 assigned. The fuel is using the fuel pump 18 via a supply line 19 a pressure accumulator 20 fed. This is a common accumulator 20 , from which the injection valves 9 for several cylinders 2 be supplied with pressurized fuel. In the supply line 19 is also a high pressure pump 22 with an associated quantity control valve 21 intended. The high pressure pump 22 Serves through the fuel pump 18 with relatively low pressure (about 3-6 bar) pumped fuel the pressure accumulator 20 at high pressure (typically up to 150-200 bar). The high pressure pump 22 is doing this by appropriate coupling with the crankshaft 13 driven. The electrically controllable quantity control valve 21 serves to that of the high-pressure pump 22 on the intake side supplied fuel flow for the purpose of pressure control in the accumulator 20 adjust. The same purpose is served. Pressure control valve 23 , about soft in the accumulator 20 located fuel via a return line 24 into the supply line 19 or the fuel tank 17 can flow back. To monitor the pressure in the accumulator 20 is a pressure sensor 25 intended.

The internal combustion engine 1 is a regulator device 26 assigned, which is connected via signal and data lines with all actuators and sensors. In the regulator device 26 Map-based engine control functions (KF1 to KF5) are implemented by software. Based on the measured values of the sensors and the map-based engine control functions, control signals are sent to the actuators of the internal combustion engine 1 sent out. So is the regulator device 26 via data and signal lines with the fuel pump 18 , the quantity control valve 21 , the pressure control valve 23 , the pressure sensor 25 , the air mass sensor 5 , the throttle 6 , the spark plug 10 , the injector 9 , the inlet valve 8th , the exhaust valve 11 , the coolant temperature sensor 14 , the speed sensor 15 and the lambda sensor 16 coupled.

In 2 is the basic structure of an electrically operated valve 50 shown schematically for metering a fluid flow. The fluid may be gases or liquids. In a housing 40 of the valve 50 is an exit opening 41 formed, which by a movable slide 42 , here in the form of a valve needle, can optionally be opened or closed. The outlet opening 41 is via a fluid channel 43 with a fluid reservoir or a fluid source 50 connected. In the open state, therefore, the fluid can through the outlet opening 41 escape. When closed, the fluid flow is interrupted.

The slider 42 is with a return spring 44 coupled, which the slider 42 pushes into the closed position. The shaft of the slider 42 has magnetic material. To move the slider 42 is a current-carrying coil package 45 intended. The coil package 45 is with a (not shown) power supply and the regulator device 26 (please refer 1 ) connected. By appropriate energization of the coil package 45 can the slider 42 be moved due to the occurring electro-magnetic forces. The degree of opening or the effective opening cross section of the valve 50 may be due to the size of the exciter current for the coil package 45 be set. Thus, the height of the excitation current provides a measure of the position of the slider 42 dar. The coil package 45 and the slider 42 form the actuator of the valve 50 ,

The valve 50 is integrated as an actuator in a control loop. A control circuit for controlling such an electrically operated actuator A is shown schematically in FIG 3 shown. By means of the control loop, the position of the actuator A, here the opening stroke of the slider 41 , be controlled to a predetermined setpoint SW. For this purpose, the actual value IW of the control variable, here the excitation current supplied to the actuator A, measured and the regulator device 26 fed. However, the current position of the actuator A can alternatively be determined by means of a suitable position sensor (not shown). From the regulator device 26 supplied setpoint SW and the actual value IW for the controlled variable, the difference is formed and fed as a so-called control deviation RA a th implement in the regulator device th controller R. The signal of the deviation is previously impressed on an additional signal ZS. The signal of the control deviation and the superimposed additional signal ZS are fed to the controller as so-called regulator input variables REG.

Based on the regulator input variable REG, the regulator R forms a regulator output variable RAG, which is supplied to the actuator A in the form of a control signal SS. Due to the imprinting of the additional signal ZS, the control signal SS generated by the controller R for the actuator A is such that it performs time-recurring deviating movements by the predetermined desired value SW. This may, for example, be a periodic, high-frequency oscillation around the setpoint SW. For this purpose, the additional signal ZS can represent a periodic triangular, rectangular or sinusoidal oscillation. The amplitudes of this vibration are very low compared to the setting strokes of the actuator A and the frequency is so high that, for example, in the valve 50 practically no effect on the amount of fluid to be measured is noticeable.

By These deviations will be an adhesion of the actuator in the desired position effectively prevented. When changing position or position of the actuator A, it is therefore no longer necessary, by means of one raised Energy input, for example by means of an increased excitation current, the Release actuator A from the old target position. This can an overshoot of the actuator A prevents and a new target position with high Speed and precision be set.

The control method described above for the actuator A and the associated regulator device 26 offer the advantage that the actuator A performs a controlled, time-recurring deviation movement about the setpoint SW. This is achieved in that the additional signal ZS is supplied to the regulator R as a regulator input variable REG. This offers the advantage that external disturbances which influence the deviation movement of the actuator A, such as Temperaturschwan fluctuations or age-related stiffness automatically be taken into account in the design of the control signal.

The method described above is suitable in general for actuators whose position can be detected and which are integrated as an actuator in a control loop. In the field of motor vehicles or internal combustion engines, examples of application examples would be volumetric flow control valves for regulating pressure in the fuel pressure accumulator and tank venting valves. In principle, however, the invention is also applicable to electric actuators of other components, such as those of exhaust gas recirculation valves, throttle valves, swirl valves, injectors, intake and exhaust valves.

Claims (5)

Method for regulating the position of an electrically movable actuator (A) for an internal combustion engine ( 1 ), wherein - an actual position value (IW) is measured, which is representative of the actual position of the actuator (A), - a position set value (SW) for the actuator (A) is determined, - a difference (RA) from the position actual value (IW) and the position setpoint (SW) is determined, - the difference (RA) an additional signal (ZS) is impressed in the form of a periodic oscillation, - the controller (R) with the additional signal (ZS ) superimposed difference (RA) is supplied as a regulator input variable (REG), and wherein - the additional signal (ZS) is designed such that the controller (R) based on the difference (RA) and the set signal (ZS) a Reglerausgangsgröße (RAG ) in the form of a control signal (SS) for the actuator (A), which is such that the actuator (A) performs a controlled, time-recurring deviation movement from the position setpoint (SW). The method of claim 1, wherein the additional signal (ZS) is formed such that the deviation movement is a periodic Oscillation around the position setpoint (SW). Method according to one of claims 1 or 2, wherein the controller output (RAG) has the form of a pulse width modulated control signal (SS) and the Deviation movement caused by corresponding variation of the duty cycle becomes. Method according to one of claims 1 to 3, wherein the additional signal (ZS) is rectangular, triangular, or sinusoidal. Regulator device ( 26 ) for an internal combustion engine ( 1 ), which is designed with means such that the method according to claim 1 can be carried out.