DE102008032482B3 - Method for detecting malfunction in glow system in motor vehicle e.g. during idle phase of engine, involves modulating glowing operation, determining measuring data and connecting or disconnecting system components - Google Patents

Abstract

The method involves modulating a glowing operation of one of glow devices for detecting a malfunction at a glow system. Measuring data of other system components of an internal-combustion engine of a motor vehicle is determined in dependence of the modulation of glow operation of one of the glow devices. The system components are connected or disconnected in dependence of the glow operation of the glow devices. The glow devices are deactivated or activated for detecting malfunction in the glow system. An independent claim is also included for a fault-diagnostic device comprising an electrical battery voltage measuring unit.

Description

The On the one hand, the invention relates to a method for detecting a malfunction at an annealing plant to glow of glowing devices a self-igniting Internal combustion engine, in particular of a motor vehicle. on the other hand The invention relates to a fault diagnosis device for detecting a malfunction at an annealing plant to glow of glowing devices a self-igniting Internal combustion engine, in particular of a motor vehicle, in which the fault diagnosis device by means of suitable connection means on a data peripheral of Motor vehicle can be connected.

Especially a method for detecting a malfunction in an annealing system can by means of an on-board diagnostic system of a motor vehicle can be made, however, a cause of the error can only be limited Measured measurements become. For example, it can be determined if an electrical Short circuit in an injection system of a self-igniting Internal combustion engine is present. Should, however, in particular at one Glow the injection system of the self-igniting Internal combustion engine present a plausibility error, such as due to a critical age of a glowing device of the annealing plant, This usually can not be done using the on-board diagnostic system be recognized with sufficient accuracy. This often causes arbitrary system components the self-igniting Internal combustion engine to be replaced, since no exact knowledge about the actual error function can be determined. For example, come it malfunction of a self-igniting internal combustion engine again and again, that injectors of an injection system exchanged although the actual cause of failure at an annealing plant to glow of glowing devices the self-igniting Internal combustion engine can be found. Such malfunctions can occur especially in cold ambient temperatures to start problems, restless Internal combustion engine, especially immediately after takeoff the internal combustion engine, and / or to a critical smoke to lead.

From the EP 1 350 951 A2 For example, a method and apparatus for detecting faults on the glow plugs of a diesel engine are known. In this case, the possibility of the occurrence of a fault is checked on the glow plugs without a forced change in the supply state of the glow plugs in a first step. Only when the possibility of occurrence of a fault in the glow plug is detected, in a subsequent step, is a detection of the fault using a forced change in the supply state of the glow plugs and using measurement data from other system components of the diesel engine.

It object of the present invention is in particular an arbitrary Replacing components on a self-igniting internal combustion engine to avoid.

The The object of the invention is on the one hand by a method for detecting a malfunction on an annealing system to glow of glowing devices a self-igniting Internal combustion engine solved in particular a motor vehicle, at which for detecting the malfunction of the annealing an annealing operation at least one of the glowing devices is modulated.

According to the invention by means of modulating the annealing operation at least one of the glowing devices a malfunction of the annealing system reliable be recognized, since by this modulating the annealing operation at least one of the glowing devices is directly affected, causing a malfunction of the corresponding glow device immediately recognized by the effect of the modulation of this glow device can be, with measurement data from other system components of the internal combustion engine dependent on a modulation of an annealing operation at least one of the glowing devices be determined.

Of the Term "modulate" or "modulation" describes in the sense of the invention, at least one variation of the glow intensity of the glow devices in annealing mode. In a simple case, a modulation of a glow device may occur in activating or deactivating a single glow device an annealing system reflect.

in the The context of such a modulation can manifest itself as an effect of the modulation operating conditions the self-igniting Internal combustion engine already measurably change, causing a malfunction at the annealing plant procedurally very easy to determine.

Of the Term "annealing plant" describes in the present case a system component of the self-igniting internal combustion engine, by means of which an annealing operation for Operating a self-igniting Internal combustion engine can be accomplished. For example, includes such an annealing system individual glowing devices, like glow plugs, and Glühanlagenrelais respectively Glüheinrichtungsrelais, by means of which glow phases the glowing equipment can be regulated.

The term "annealing operation" describes in particular an operating state on a glow device, in which the glow device is heated or heated, in particular by means of electrical energy is made to glow. As a rule, the glow devices are realized by glow plugs, as already indicated above.

Favorable Way, the present method is characterized in particular by it out that by evaluating a system reaction on a self-igniting Internal combustion engine due to a targeted Glühkerzenaktivierung a malfunction of activated glow plug can be recognized.

Becomes in the course of such a modulation for detecting the malfunction at least one of the glowing devices disabled or enabled, this is especially true in other system areas the internal combustion engine or a motor vehicle noticeable, thereby a malfunction can be recognized particularly well.

With The term "deactivate" is in particular a shutdown of a glow device or switching off an annealing operation of a glow device described while accordingly with the term "activate" a power a glowing device or switching on an annealing operation of a glow device is described.

The The object of the invention is about in addition to a fault diagnosis device for detecting a malfunction at an annealing plant to the glow of Glüheinrichtungen a self-igniting internal combustion engine in particular a motor vehicle, in which the fault diagnosis device by means of suitable connection means on a data periphery of the motor vehicle can be connected, with the fault diagnosis by Means for activating and / or deactivating one or all Glüheinrichtungen distinguished.

It it is understood that in the present method for detecting a malfunction on an annealing system just one of the glowing facilities in terms of their Glühbetriebes can be modulated, wherein the annealing of the Glüheinrichtungen can also be modulated individually one after the other.

Should vehicle-specific or combustion engine specific such a single modulation can not be made, sees an alternative variant of the method that several Glüheinrichtungen or all glows be modulated. For example, this may be the case when using an annealing plant relay all glows can only be controlled together.

Especially In this context, it is advantageous if a malfunction one of the glowing facilities by means of a modulated annealing operation at least one of the glowing devices is determined. In this respect, the present method is for recognizing a malfunction on an annealing system or in this regard Glüheinrichtungen particularly uncomplicated feasible.

The present methods can be further improved if at least one of the glowing facilities dependent on further operating parameters of the internal combustion engine modulated, in particular deactivated or activated, will.

Of the Term "operating parameters" describes herein, that further system components of the internal combustion engine in particular while modulating one of the annealing devices in addition to their functions changed can be.

Furthermore is advantageous if in dependence of the annealing operation at least one of the glowing devices other system components of the internal combustion engine added or shut off. Will the other system components of the Internal combustion engine switched on or off, may change with respect to an internal combustion engine operation particularly well noticeable making a malfunction on a glow device much clearer or can be detected faster.

A Another advantageous variant of the method provides that measurement data from other system components of the internal combustion engine depending a modulation of an annealing operation at least one of the glowing devices be determined. This can be changes be recognized well with respect to an internal combustion engine operation.

It it is understood that with regard to the present method a Variety of different test routines made or set can be. Hereinafter, an advantageous test routine will be described by way of example, in which in terms of the present method in a first Process step with deactivated glow operation of the glowing devices a temperature by means of an exhaust gas temperature sensor of an exhaust system the internal combustion engine, preferably by means of an output valve nearest exhaust gas temperature sensor the internal combustion engine, is determined. This is, preferably with the ignition switched on, determines the temperature at the exhaust gas sensor and for subsequent Evaluations ideally cached. Are the Glüheinrichtungen sufficiently long enough, so that the internal combustion engine was not operated for a sufficiently long period of time the measured temperature on at least one of the exhaust gas temperature sensors essentially the ambient temperature.

Favorable Way will in a next step with deactivated fuel injection of the internal combustion engine the annealing operation at least one of the glowing devices activated and monitors an electrical voltage of an electrical vehicle electrical system. It is important to ensure that ideally no further electrical Consumer of the motor vehicle on or off. As a result of the activation of at least one of the glowing devices There will be a brief dip in battery voltage as well subsequent increase of the battery voltage to below the Set the output levels of the battery voltage before activating the glowing device. It follows that a malfunction of each activated glow device can be excluded, as a result of activating the Glüheinrichtung a voltage drop can be determined. That's why it's special advantageous in this context if an electrical voltage an electrical vehicle electrical system is monitored. Alone by means of monitoring the electrical voltage in particular when activating the glow device it can be determined whether the glowing device works properly, the features regarding this process step are also without the remaining Features of the invention advantageous.

It It is understood that with the description "monitoring the battery voltage" also a voltage monitoring the electrical system of a vehicle is detected. Thus, refers the surveillance not just on the actual battery of a vehicle.

Favorable Way, the fault diagnosis device has means for measuring an electric battery voltage an electrical vehicle electrical system on.

Depending on the annealing system the internal combustion engine can either at the same time all glowing devices or separately individual glowing devices activated at different times. The type of activation respectively Control of the individual glowing devices is essentially of the possibilities the existing annealing system dependent.

Around about that In addition, the injector of the internal combustion engine as desired disable or subsequently to be able to activate It is advantageous if the fault diagnosis device means for activating and / or Deactivating the injector of the internal combustion engine comprises.

In a further process step can then be disabled at Fuel injection, the internal combustion engine by means of an electric Starter device forcibly driven and a reference temperature determined by means of an exhaust temperature sensor of an exhaust system of the internal combustion engine become. If at least one of the firing devices is activated, it heats up the air present in a combustion chamber of the internal combustion engine, the so heated Air by means of a piston movement of the forced-driven Internal combustion engine can enter the exhaust system, the reference temperature by means of an exhaust gas temperature sensor of an exhaust system of the internal combustion engine is determined. Is the measured reference temperature higher than the previously measured start temperature with deactivated glow operation the glowing equipment is assuming that the activated glow device is working properly.

Around the electric starter device of the internal combustion engine as needed to be able to activate is it is advantageous if the fault diagnosis device means for activating and / or Deactivating an electrical starter device of the internal combustion engine comprises.

A advantageous variant of the method provides that in a subsequent process step a Temperature difference with respect to a measured initial temperature and a subsequently measured reference temperature is determined, Based on the temperature difference and knowledge to a glow power the activated Glüheinrichtung obtained can be. However, this process step can only be carried out expediently, if the used exhaust gas temperature sensors have a working range which can register ambient temperatures. this will especially with NTC exhaust gas temperature sensors will not be the case.

Furthermore it is advantageous if in a subsequent process step with activated glow operation a fuel injection of the internal combustion engine activated and the internal combustion engine is operated autonomously.

Becomes in a cumulative process step, the internal combustion engine in Idling autonomously operated and the annealing operation deactivated again, Can work properly Glow an idle speed reduction can be determined. This is because that an idle controller reduces the idling speed again when the annealing operation is deactivated. Cumulatively or alternatively it reduces also the fuel injection or its desired value, so that too in this regard Values can be used, to draw conclusions a proper function a glowing device to be able to pull.

In this context it is advantageous if the fault diagnosis device additionally comprises means for setting an idling speed of the internal combustion engine, so that during the method for detecting a malfunction a reference idling speed can be set on the internal combustion engine.

Is working an exhaust system of an internal combustion engine by means of NTC exhaust gas temperature sensors, it is advantageous if in an alternative process step with deactivated glow operation the exhaust gas temperature by means of an exhaust gas temperature sensor of an exhaust system the internal combustion engine is determined. The exhaust gas temperature is in this case preferably in terms of idling Internal combustion engine measured.

Advantageous is it, if in an alternative further process step the Glühbetrieb at least one of the glowing devices again activated and again the exhaust gas temperature by means of an exhaust gas temperature sensor an exhaust system of the internal combustion engine is determined. By the Activate a glow device should the total exhaust gas temperature rise when the glowing device properly glows.

The Exhaust gas temperatures are in the two alternative process variants both far above the ambient temperatures, so that more advantageous Make a temperature difference even when using commercially available NTC exhaust temperature sensors can be determined.

It is understood that the present method in different Manner and at different times can, wherein a further advantageous variant of the method provides that the method in a workshop or in a stationary driving a motor vehicle, such as idle phases and / or shear phases of a Internal combustion engine, performed can be. However, to the fault diagnosis device described here Do not always carry on-board with a motor vehicle have to, is suitable for performing the present method of workshop operation particularly well. On the other hand, to carry out the process continuously can, is suitable Alternatively, any stationary operation of an internal combustion engine, which to perform of the present process persists long enough.

It It is understood that the individual stages of the procedure manually or be carried out automatically can, so that an advantageous variant of the method provides that individual Procedural phases started or executed manually or automatically can be stopped.

Around The measured data determined in this case also at a later date be able to retrieve or evaluate, it is advantageous if the fault diagnosis device Furthermore, means for evaluating and / or storing determined Measurement data with respect to the method explained here.

In order to the risk can be reduced that other electrical consumers a motor vehicle measurement data during a determination, in particular with respect to an electrical voltage of an electrical vehicle electrical system, falsify, It is advantageous if the fault diagnosis device means for activating and / or Deactivating electrical consumers of a motor vehicle includes. Electrical consumers can in this context For example, be an air conditioner or servo motors on a motor vehicle.

Favorable The manner becomes particular by means of the method described above Targeted maintenance and / or repair measures possible, for example in terms a defective glow plug an internal combustion engine, so that an arbitrary exchange in particular of annealing plant components or other system components of an internal combustion engine avoided can be. This allows costs for the vehicle owner or warranty costs of a vehicle manufacturer considerably be lowered.

Further Advantages, objects and characteristics of the present invention explained with reference to the following description attached drawing in which exemplary stable idling phases of an internal combustion engine during a Method for detecting a malfunction in an annealing system with activated glow plugs and with deactivated glow plugs are shown.

In order to be able to obtain reliable evaluation results with regard to the method described above, it is advantageous if at least the initial conditions described below can be fulfilled on a self-igniting internal combustion engine or on a motor vehicle. On the one hand, an internal combustion engine must still be able to be started and operated, for example in the standby operation of a motor vehicle during a workshop stay. In addition, the internal combustion engine would ideally have to be able to be operated at low load or at low torque in a stationary operating state. Furthermore, it is advantageous if a low-consumption operating mode can be selected on the internal combustion engine in which, if possible, only a constant main injection is active in order to avoid exhaust gas temperature cause fluctuations due to a change in fuel combustion. Also, in this context, a low idle speed, such as about 700 U / min, could be set with respect to the engine. Components, in particular of a fuel intake tract and of an exhaust system of the internal combustion engine, should be able to operate well, ie at least not be defective.

It shows

the single figure schematically a speed curve and fuel consumption a self-igniting Internal combustion engine in an idling phase on the one hand with activated glow plugs and on the other hand with deactivated glow plugs.

In the diagram shown in the single figure 1 are at the abscissa 2 the time and the ordinate 3 illustrates a glow plug glowing activity, a fuel consumption, and a speed history of a self-igniting engine, with the upper curve 4 the glow plug activity, with the curve below 5 the fuel consumption and with the lower curve 6 the speed curve is entered during a method for detecting a malfunction in an annealing system for annealing glow plugs. It can be clearly seen that both in a first annealing phase 7 with activated glow plugs as well as in a subsequent further non-annealing phase 8th When the glow plugs are deactivated, there is essentially always a stable idling speed at the self-igniting internal combustion engine, while the detection method on which the invention is based is carried out.

All Features disclosed in the application documents are considered to be essential to the invention as long as they are individually or in combination with respect to State of the art are new.

Claims (14)

A method for detecting a malfunction in an annealing system for annealing Glüheinrichtungen a self-igniting internal combustion engine, in particular a motor vehicle, wherein for detecting the malfunction of the annealing an annealing operation of at least one of the glowing is modulated, and in which measurement data from other system components of the internal combustion engine in dependence Modulation of an annealing operation of at least one of the annealing means are determined, characterized in that depending on the annealing operation of at least one of the annealing devices other system components of the internal combustion engine are connected or disconnected. Method according to claim 1, characterized in that that for detecting the malfunction at least one of the glowing devices disabled or activated. Method according to one of claims 1 to 2, characterized that a malfunction of a single of the Glüheinrichtungen by means of a modulated annealing operation at least one of the glowing facilities is determined. Method according to one of claims 1 to 3, characterized that in one process step with deactivated glow operation the glowing equipment an initial temperature by means of an exhaust gas temperature sensor Exhaust system of the internal combustion engine, preferably by means of an output valve nearest Exhaust gas temperature sensor of the internal combustion engine, is determined. Method according to one of claims 1 to 4, characterized in one method step, the annealing operation of at least one of Glüheinrichtungen activated and monitors an electrical voltage of an electrical vehicle electrical system becomes. Method according to one of claims 1 to 5, characterized that in a process step with still deactivated fuel injection, the Internal combustion engine by means of an electric starter device forcibly driven and a reference temperature by means of a Exhaust gas temperature sensor of an exhaust system of the internal combustion engine is determined. Method according to one of claims 4 to 6, characterized that in a subsequent Process step a temperature difference with respect to a measured Initial temperature and a subsequently measured reference temperature is determined. Method according to one of claims 4 to 7, characterized that in a subsequent step with activated Annealing operation one Fuel injection of the engine is activated and the Internal combustion engine is operated autonomously. Method according to one of claims 1 to 8, characterized that in a cumulative process step, the internal combustion engine operated autonomously in idle mode and the annealing operation deactivated again becomes. Method according to one of claims 1 to 9, characterized in that in an alternative method step with deactivated Glühbetrieb the exhaust gas temperature by means of an exhaust gas temperature Temperatures Sors an exhaust system and / or the speed or its target value, and / or the fuel quantities and / or the torques of the internal combustion engine is determined and activated in an alternative further process step, the glow operation of at least one of the glowing again and the exhaust gas temperature by means of an exhaust gas temperature sensor of an exhaust system the internal combustion engine is determined. Method according to one of claims 1 to 10, characterized that the method in a workshop or in a stationary driving a motor vehicle, such as idle phases and / or shear phases of a Internal combustion engine, performed becomes. Fault diagnostic device for detecting a malfunction at an annealing plant to glow of glowing devices a self-igniting Internal combustion engine, in particular a motor vehicle, characterized characterized in that the fault diagnosis device by means of suitable connection means be connected to a data peripheral of the motor vehicle may as well as means for activating and / or disabling individual or all glowing devices and Means for connecting or disconnecting other system components the internal combustion engine in dependence of the annealing operation at least one of the glowing devices having. Fault diagnostic device according to claim 12, characterized by means for measuring an electric battery voltage of a electrical vehicle electrical system and / or means for activating and / or Deactivation of an injection device of the internal combustion engine and / or Means for activating and / or deactivating an electrical starter device the internal combustion engine. Fault diagnosis device according to one of claims 12 to 13, characterized by means for evaluating and / or storing of determined measurement data with regard to the method after a the claims 1 to 11.