DE102007043607A1 - Method and control for monitoring the function of an internal combustion engine - Google Patents

Abstract

A method for operating an internal combustion engine (1) of a vehicle is described in which engine parameters, in particular the position of pistons (20) in individual cylinders (22) and the rotational speed, are determined by means of sensors and a drive control (6) Electric motor (electric motor) (4) with the internal combustion engine (1) is coupled. In order to determine the functionality of the internal combustion engine, in particular the compressibility of the internal combustion engine (1), quickly and easily during vehicle operation, torque values determined from operating characteristics of the electric motor (4) are determined as diagnostic methods and evaluated synchronized with the engine characteristics, the torque values with stored reference values closed and on deviation of the torque values outside a fixed tolerable range on Fahler in the compression behavior closed.

Description

The The invention relates to a method for operating an internal combustion engine a vehicle in which by means of sensors and a drive control Motor characteristics, in particular the position of piston in individual Cylinders and the speed can be determined using an electric motor (electric motor) is coupled to the internal combustion engine. The invention relates to a computer program product, a controller for a drive of a vehicle and a maintenance device with a Display and an interface to the controller.

One Internal combustion engine draws in ambient air when the cylinder is open Inlet valves, the subsequently compressed Ambient air with fuel and ignites the fuel-air mixture. In the gasoline engine this is done with the help of a spark. The diesel engine is capable of autonomous fuel-air mixture to ignite.

Around to start the internal combustion engine is the internal combustion engine with coupled to an electric motor, at the same time as a generator for Generation of electrical energy for the electric power grid can serve a vehicle. It is known the internal combustion engine a vehicle by means of a drive control and coupled thereto To control sensors. The drive control sets the position when starting the piston in the individual cylinders and knows the speed of the internal combustion engine.

Of the Internal combustion engine must be free of mechanical damage or high wear in the best possible way Be functional state, first, to be able to suck in ambient air and second, to compress them. this will routinely at workshop visits with the examination "compression test" checked. This is done for each cylinder a pressure sensor screwed in place of the spark plug. Such a procedure is sometimes complicated and carries the danger the damage of components (eg spark plugs) and the internal combustion engine. A simplified diagnostic procedure to check the compressibility discloses the following prior art.

The DE 102 36 617 A1 describes a method for operating an internal combustion engine, wherein the pressure in a combustion chamber of at least one cylinder is detected at least temporarily during operation of the internal combustion engine by means of a pressure sensor. In order to determine the compression of a cylinder during operation of the internal combustion engine, it is proposed that the maximum value of the pressure in the combustion chamber of the cylinder is determined, which occurs during a power stroke in which the cylinder is not working. The cylinder does not work in the starting phase, in pure overrun mode and cylinder deactivation due to low power demand.

It The object of the invention is a method, a computer program, a Control and a maintenance device of the type mentioned in such a way to develop that a "state of health", in particular a compression capability of the internal combustion engine fast, simply and advantageously already during vehicle operation can be.

The The object is solved by the subject matter of patent claim 1. Advantageous developments emerge from the dependent Claims.

One essential idea of the invention is information of operating characteristics evaluate the E-machine as a diagnostic method and from to close the health of the internal combustion engine. According to the invention as a diagnostic method Operating characteristics of the electric machine determined torque values determined and synchronized to the engine characteristics known to the drive control and evaluated, the motor torque values determined therefrom with stored reference values compared, when the engine torque values deviate from the stored ones Reference values outside a specified, tolerable range is closed to errors in the compression behavior.

The inventive method has the advantage that elaborate pressure sensors in combustion chambers are not necessary. The by the provision of pressure sensors in combustion chambers occurring Problems such as shielding the pressure sensors from the heat in the Combustion chambers and an additional sealing of the pressure sensors in each combustion chamber thus eliminated completely. There one modern drive control for a combustion engine torque guided is accurate engine characteristics of the internal combustion engine such as speed and torque of the drive control known. Torque-guided means, that requested by the driver when pressing the accelerator pedal Torque on the drive control is detected due of which the internal combustion engine is controlled.

The stored reference values can for example be specified individually for each vehicle in the production process and factory-adjusted to individual manufacturing tolerances. The diagnostic method may perform either the drive control itself or a higher level controller. Since the operating characteristics of the electric motor can be easily determined by controlling the electric motor, the process can be simple be executed. The prerequisite is that the controller of the electric machine can provide information about the speed and the torque in an interface.

According to one The invention further developing embodiment are the Torque values of the electric machine are read in an operating state, in which the electric motor is driven as a generator by the internal combustion engine becomes. In this embodiment, the operating characteristics the electric motor can be determined and the torque values be read for the operating state. Here are the Torque values of the electric motor with such a large resolution evaluable, so that each individual firing cylinder recognizable is and by means of the drive control individual engine torques each individual firing cylinder of the internal combustion engine can be assigned are. This allows the health of each individual Determine the cylinder. Advantageously, the torque values become the electric machine is read when the internal combustion engine is idling is or the vehicle is at a standstill and no Torques are delivered to the drive wheels. Idle the measurement result can be determined more precisely, firstly for diagnosis arbitrary speeds are adjustable and secondly torque reducing Elements, such as the drive wheels, the torque to be measured less distort.

additionally or alternatively, the torque values of the electric motor be read in an operating state in which the internal combustion engine without fuel injection from the electric motor, especially with an idle speed, is being towed. According to this Alternatively, it is possible, conversely, if the electric motor works as an electric motor, the operating characteristics to determine the electric machine, especially for each individual Cylinder, which is in the compression stroke. If necessary an evaluation electronics of the e-machine with a more sensitive measuring range as for the operating state when the electric machine as a generator works, educated. It is understood that the electric machine, the the internal combustion engine drags, works as a starter. The electric machine can be either as a single machine with two functions, d. H. when Starter and generator working to be trained, or the electric motor can also include two machines, one exclusively is intended for generator operation and at least another works as an electric motor and the internal combustion engine starts or supports the combustion engine in a hybrid mode.

According to one particular embodiment of the invention is the diagnostic method not every time starting the internal combustion engine in a vehicle executed but the diagnostic procedure is used in special situations in particular at equal intervals in terms of time and / or in terms of a same distance covered, executed. Such intervals are for example other vehicle equipment such as the change of Engine oil or the oak of tachometers, etc. known. The distances to carry out the diagnostic procedure can should be shortened, mistakes in the compression behavior of the internal combustion engine occur.

Around make the diagnostic process even easier and safer is the diagnostic method of a controller, in particular of a hybrid drive control, designed to perform certain functions on the drive or drive train during the measurement of Torque values of the electric motor switches off and / or releases. Consequently can detect a faulty compression behavior even better Be as influencing factors that a measurement and Influence and distort evaluation, be minimized by switching off.

advantageously, the method is implemented in a hybrid drive vehicle. This has the advantage, as in a vehicle with hybrid drive in Essentially all the components are present and the process is no essential additional components required but only realized by a computer program product running in a controller can be. A hybrid vehicle has an electric motor whose Operating characteristics of a controller are known as the electric motor and the engine from a torque coordinator of a hybrid drive controller be controlled to jointly or alone certain torques available at certain speeds on the powertrain to deliver.

Consequently can during certain phases of operation of a hybrid vehicle From the operating characteristics of the electric motor, the compression torque a coupled internal combustion engine can be determined. For example in a start-stop phase, in which the electric machine with a Speed of the stopped combustion engine via a separating clutch On idle speed of the engine rotates and the transmission is selected to be neutral or disengaged in the drive train, so that there is no adhesion to the drive wheels and the vehicle is standing.

Since the temperature of the internal combustion engine, the drag torque of friction moments of the bearing and piston friction and the gas spring torque are known as well as accessory torque, a typical course of the torque applied to the e-machine can be clearly seen and evaluated for each cylinder. Thus, for every single cylinder the compression behavior can be checked.

by virtue of The amount of compression torque can affect the condition of the internal combustion engine and its wear or compression capability getting closed. Compression occurs in a cylinder of the internal combustion engine with valves closed and an upward movement of the piston.

One Compression loss can be due to a leaky cylinder-piston mating occur. So that engine oil is sucked and burned or the air-fuel mixture enters the crankcase. at reduced compression capacity decreases the efficiency of the internal combustion engine very strong, even to the uttermost Incapacity of the internal combustion engine, from.

According to one The invention further developing embodiment is at a deviation of the torque values outside the tolerable Range, especially depending on the size the deviation, the driver via a display and warning device reported the error in the compression behavior and / or in one Error memory recorded. The drive control determines motor characteristics, such as Fuel quantity, injection timing and different rates of injection, as well as the ignition to a particular sucked Air quantity in an engine condition. In case of a defect, for Example if the inlet valve does not close correctly, or at a wear / aging of the piston rings / cylinder changes the compression of the internal combustion engine, so based on the Determining the compression adaptation algorithms can become active which enable opti mum torque delivery, consumption and emission.

The Error entries can be taken from the error memory in the workshop are read out and thus maintenance work clearly Simplify and accelerate, because in the workshop very fast it is determined which components of the drive or the internal combustion engine working incorrectly.

According to one particular embodiment of the invention are in detection a deviation of the engine torque values within a first range These errors are recorded and / or an intervention is made in the drive control of the internal combustion engine, thus engine operating characteristics adapted to the deviation for the internal combustion engine and / or within a larger second area The electric motor also boosts as a drive used and / or within a very large third Range of operation of the internal combustion engine time and / or distance-dependent restricted or completely failed. The invention Method can thus be the deviation of the torque values in at least assign three different areas, the different reactions trigger to counteract the compression loss. At a largest deviation may be the further operation of the Vehicle to be set to a larger one Damage to the vehicle, in particular to the drive or its exhaust system, For example, the destruction of the catalyst, to prevent.

According to the invention the task also solved by a computer program product, which is stored in a program memory of a controller, such as the drive control, with program instructions is loadable to all steps of the procedure described above execute when the program in the drive control or in the hybrid drive control. This has the advantage that the invention essentially a program memory for Must provide, in which the inventive Procedural steps implemented are executable. The components and information is present, for example, in a hybrid vehicle, so that only the computer program product with the method steps is introduced.

The Invention is therefore simple and inexpensive to implement.

A Control according to the invention, in particular drive control or hybrid propulsion control, of a vehicle performs this method described above by means of the computer program.

The The invention is also achieved by a maintenance device with a display and an interface to the controller solved to error values from the error memory of the drive control or the deviation of engine torque values of reference values during the Execution of the diagnostic procedure read out. this has the advantage that the maintenance device is simple and no expensive measuring equipment must have or special Embodiments required.

It It is understood that the above and below to be explained features not only in the specified Combination, but also usable in other combinations.

The Invention will be described below with reference to an embodiment explained in more detail with reference to drawings. Show it:

1 a schematic circuit diagram of a hybrid vehicle with a control according to the invention and

2 a flow chart of the method according to the invention.

The 1 shows a schematic circuit diagram of a hybrid vehicle with an internal combustion engine 1 , its output shaft to the drive train 2 is connected to drive wheels 3 drive. The powertrain 2 includes a controllable transmission, differential, possibly converter and a controllable starting clutch. The powertrain 2 is with an electric motor (electric machine) 4 coupled. The electric machine 4 transmits as a starter via a controllable separating clutch 41 a torque to the internal combustion engine 1 in start-up phases. The electric machine 4 serves as a generator for supplying the hybrid vehicle with electrical energy. The electrical energy is stored in an energy store 5 , such as a battery and / or high performance capacitors stored. The internal combustion engine 1 is with a drive control 6 connected. The drive control 6 receives from a signaler 7 For example, an accelerator pedal, torque requests from the driver and implements this, are controlled in the ignition, the air-fuel ratio and, where appropriate, gas exchange valves accordingly. The drive control 6 considered by means of a temperature sensor 9 the temperature of the internal combustion engine 1 , A hybrid drive control 8th is the drive control 6 superior and controls the switching on and off of the internal combustion engine and the interaction of e-machine 4 and internal combustion engine 1 , The hybrid drive control 8th can the electric machine 4 torque-controlled drive to a certain moment on the drive wheels 3 to create.

The hybrid drive control 8th recorded via suitable sensors 11 The speed and the consumed, electrical drive energy of the electric motor 4 , The drive control 6 and / or the hybrid drive control 8th are thus the operating characteristics of the electric motor 4 in order to calculate therefrom the torque values and then to engine torque values of the internal combustion engine 1 close.

According to the invention, the hybrid drive control comprises 8th a diagnostic module 10 that in a program memory 12 loaded, and to 2 executes the method according to the invention described below. In the program memory 12 are stored separately in a table reference values for the internal combustion engine with respect to torque, speed and temperature for a "healthy" operating state 14 within the program memory 12 recorded.

The hybrid drive control 8th has an interface 13 on that to an interface 18 a maintenance device 16 with an ad 17 is customized, and connect to the interface 13 the hybrid drive control 8th creates error values or diagnostic results with regard to the engine torque from the internal combustion engine from the diagnostic module 10 from the error memory 14 read.

The 2 shows a flowchart with a sequence of the method according to the invention. At certain regular intervals, which may be temporal and / or dependent on the distance traveled, the following diagnostic procedure is performed.

In step S1, the position of the in the 1 shown piston 20 in individual cylinders 22 and the speed of the internal combustion engine 1 determines the drive control 6 detected.

In step S2, the operating characteristics of the electric motor become 4 Torque values determined, either in generator mode or when the electric motor 4 the internal combustion engine 1 drives or hauls. If the electric machine 4 As a drive motor works, the torque values of the hybrid drive control 8th at the electric machine 4 requested.

In step S3, the determined torque values of the electric machine 4 to the engine characteristics of the internal combustion engine 1 evaluated synchronized and derived therefrom engine torque values of the internal combustion engine 2 with stored reference values in the program memory 12 compared. The torque values of the electric motor 4 are so precise that they are each cylinder 22 of the internal combustion engine 1 are assignable.

in the Procedure now follow three queries A1, A2, A3, the tiered are and check if and to what degree the measured Engine torque values differ from the stored reference values. It is understandable that the measured engine torque values Represent averages to eliminate measurement errors.

In the first step of query A1, it is determined whether the deviations of the engine torque values are outside a set tolerable range. If this is not the case, then the procedure goes to step S4 and stops in the program memory 12 notice that the internal combustion engine 1 is in a "healthy" state, so that the compression behavior is not limited by zeroing a counter after a certain time interval or after a certain Wegstrekke the procedure is repeated from start.

If, on the other hand, an error is detected, it is checked in a second query A2 whether the error lies in a first range or above in a second range. If the error is not in the second range, this leads to an entry in the error memory in a step S5 14 , In addition, adaptation algorithms in the drive control 6 active, in order to positively change the negative influence of the compression behavior by a changed ignition timing. It is therefore an intervention in the drive control 6 of the internal combustion engine 1 made so that engine operating characteristics for the internal combustion engine 1 adapted to the deviation.

If the deviation of the error can be assigned to a larger, second range, which is determined in the query A2 by affirming and by negating the query A3, then the electric machine becomes 4 reinforced as a drive in addition to the internal combustion engine 1 used according to step S6. Incidentally, the procedure is performed more frequently than the setting in step S4 due to detected errors.

If, on the other hand, the error is so great that there are threats of greater damage, which is found in a query A3 by affirmative action, then either the operation of the internal combustion engine can take place 1 be completely failed to protect other components, such as the catalyst, from damage. Alternatively, the driver is prompted by appropriate warning displays to urgently visit the nearest workshop for repair. The inventive method is as a computer program product in a program memory 12 the hybrid drive control 8th loadable and performs the procedure according to 2 out.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10236617 A1 [0005]

Claims (10)

Method for operating an internal combustion engine ( 2 ) of a vehicle, according to which by means of sensors and a drive control ( 6 ) Engine characteristics, in particular the position of pistons in individual cylinders and the speed are determined, wherein an electric motor (electric motor) ( 4 ) with the internal combustion engine ( 1 ) is coupled, characterized in that as a diagnostic method from operating characteristics of the electric motor ( 4 ) and are evaluated in synchronized fashion with the engine characteristic values, the engine torque values determined therefrom are compared with stored reference values and, if the torque values deviate from a set tolerable range, errors in the compression behavior are inferred. A method according to claim 1, characterized in that the torque values of the electric motor ( 4 ) are read in an operating state in which the electric machine ( 4 ) as a generator of the internal combustion engine ( 1 ) is driven. A method according to claim 1, characterized in that the torque values of the electric motor ( 4 ) are read in an operating state in which the internal combustion engine ( 1 ) without fuel injection from the electric motor ( 4 ), in particular with an idle speed, is towed. Method according to one or more of the preceding Claims 1 to 3, characterized in that the diagnostic method in special situations, especially at equal intervals in in terms of time and / or in terms of an equal amount Distance, running. Method according to one or more of the preceding claims 1 to 4, characterized in that the diagnostic method of a hybrid drive control ( 9 ), which performs certain functions on the drive during the measurement of the torque values of the electric motor ( 4 ) turns off and / or releases. Method according to one or more of the preceding Claims 1 to 5, characterized in that at deviation the torque values outside the tolerable range, especially depending on the size of the Deviation, via a display and warning device of Error is communicated to the driver and / or recorded in a fault memory becomes. Method according to one or more of the preceding claims 1 to 6, characterized in that upon detection of a deviation within a first range, an intervention in the drive control ( 6 ) of the internal combustion engine ( 1 ) is carried out so that engine operating characteristics for the internal combustion engine ( 1 ) are adapted to the deviation and / or within a larger second range, the electric machine ( 4 ) is used as drive additionally used and / or within a very large third range, the operation of the internal combustion engine ( 1 ) is temporally and / or remotely dependent restricted or completely failed. Computer program product stored in a program memory ( 12 ) is loadable with program instructions to carry out all the steps of a method according to at least one of claims 1 to 7, when the program is in a drive control ( 6 ) or hybrid drive control ( 8th ) is performed. Control, in particular drive or hybrid drive control, of a vehicle, the method according to a or more of claims 1 to 7 by means of a computer program product carries out according to claim 8. Maintenance device ( 16 ) with an advertisement ( 17 ) and an interface ( 18 ) for controlling according to claim 9, error values from the error memory ( 14 ) of the drive control ( 6 ) or the deviation of engine torque values from reference values during the execution of the diagnostic procedure.