DE102016207305B3 - Method and device for monitoring a hand-held or hand-carried internal combustion engine - Google Patents

Abstract

The invention relates to a method for monitoring a hand-held or hand-carried internal combustion engine (4) with an internal combustion engine (6) and an ignition device (16) coupled thereto, wherein when the ignition device (16) is ignited, a pulse-shaped ignition signal (62) is generated, which is wireless to a mobile operating and display device (64), in particular a smartphone, is transmitted, and wherein in the operating and display device (64) an application software (78) is deposited, with which a number of temporally successive ignition signals (62) for determining a Operating state of the internal combustion engine (4) is evaluated.

Description

The invention relates to a method for monitoring a hand-held or hand-carried internal combustion engine with an internal combustion engine and an ignition device coupled thereto. The invention further relates to a device operating according to such a method.

Hand-held or hand-held internal combustion engines as implements, such as chainsaws, leaf vacuum (Laubblasgeräte) or lawn mower, are usually driven by a motor. If these implements are to be operated essentially independently or over a comparatively long period of time, an internal combustion engine is usually used as the drive motor. The reason for this is that refilling a fuel can be done comparatively time-saving and only comparatively robust tools are needed. Also, the storage of such powered implements over a relatively long period is possible, whereas when operated by a battery electromotive equipment before use any discharge of the battery must be considered.

To reduce manufacturing costs, the internal combustion engines typically have an adjustable carburetor with which the mixing ratio of an air-fuel mixture in a combustion chamber of the internal combustion engine can be adjusted by a user. The ignition of the air-fuel mixture in the combustion chamber during internal combustion engine operation is usually carried out by means of an ignition device. Such igniters generate a spark initiating combustion or ignition pulse, which is produced by a discharge of a starting capacitor at a spark plug within the combustion chamber. The spark plug is in this case contacted by means of an ignition cable to the ignition capacitor, wherein the ignition capacitor is charged in operation by means of a coupled to a magnetic generator charging coil or has been.

In the operation of internal combustion engines, high demands are placed on the performance of the ignition devices, so that existing guidelines regarding noise emission and electromagnetic compatibility (EMC) as well as application-specific safety regulations are met. Thus, for example, at the time of the spark in the ignition cable and the spark plug by the capacitor discharge creates a pulse-shaped high-frequency signal, which is emitted with the ignition cable in the function of an antenna.

In order to ensure a safe and reliable operation of the internal combustion engine or the working device, it is necessary to always produce the best possible air-fuel mixture within the combustion chamber. Among other things, the optimum mixing ratio depends on the fuel used as well as on external influences such as the ambient temperature and the ambient pressure. As a result, it is sometimes necessary for the user to adjust or adjust corresponding valves of the carburettor before or during operation. The setting is typically carried out as a function of an engine speed, so that there is a need for the user to determine the current engine speed as accurately as possible during operation of the internal combustion engine and / or to monitor.

For this purpose, it is possible to use so-called tachometers or speedometers as measuring systems which can determine the engine speed, for example optically by means of a reflection of a laser beam. Also conceivable are capacitive or inductive measuring systems which receive the high-frequency signal at the ignition cable and determine from the repetition rate of the speed or speed curve of the internal combustion engine. The user thus disadvantageously requires an additional device for detecting the engine speed. This means that additional costs for the purchase of such a measuring system arise on the user side.

From the US 2014/0250991 A1 For example, there are known a system and method for adjusting the ignition timing of an engine using a stroboscope and a wireless terminal communicating therewith, which sends an ignition signal of a spark plug of the engine to the stroboscope, which drives an LED in synchronism with the ignition signal. A user can observe a mark on the engine by means of the stroboscope and determine a necessary setting of the ignition time.

From the DE 10 2010 018 446 A1 For example, there is known a method of simulating a low current firing switch in which user selectable communication data is transmitted from a host computer to a microcontroller-integrated printed circuit board assembly (PCBA) and the communication data is transformed into semiconductor signals that simulate desired power mode parameters. The semiconductor signals are transmitted to a power master module (PMM) to thereby simulate operation of the low current firing switch.

From the US 5,442,553 A is a system for wireless engine diagnostics of a vehicle and for a Software upgrate known, with a Transciever and an additional memory are connected to a vehicle-mounted microprocessor, that at least selectively stored working data and sent periodically to a remote station and diagnosed there to possibly send back a repair solution to the vehicle.

The invention has for its object to provide a particularly suitable and user-friendly method for monitoring a hand-held or hand-carried internal combustion engine. Furthermore, the invention has for its object to provide a working device according to such a method.

With regard to the method, the object with the features of claim 1 and in terms of the device with the features of claim 5 is achieved according to the invention. Advantageous embodiments and further developments are the subject of the respective subclaims.

The inventive method is suitable for monitoring a hand-held or hand-carried internal combustion engine with an internal combustion engine and an ignition device coupled thereto and set up. For this purpose, an operating state of the internal combustion engine is detected and evaluated. During operation of the internal combustion engine, a pulse-shaped ignition signal is generated during ignition of the ignition device, that is to say in the generation of a spark for triggering the combustion of an air-fuel mixture in a combustion chamber of the internal combustion engine. The internal combustion engine is preferably a two-stroke engine, so that the ignition signal is generated only once per engine revolution. The ignition signal is transmitted wirelessly to a mobile operating and display device.

The operating and display device is for example a mobile phone, in particular a mobile phone with a computer function or a smartphone or even a tablet computer. According to the method, the operating and display device has a stored application software with which a number of chronologically successive ignition signals are evaluated for determining the operating state. For this purpose, the application software (application software) is preferably installed or installed on the operating and display device as a so-called app or mobile app (mobile application, smartphone app).

The ignition signal is an interference signal of the internal combustion engine that occurs during operation. In this case, an interference signal is to be understood as meaning, in particular, an electromagnetic and / or acoustic signal which is transmitted to the operating and display device in a senderless manner. In this case, the fact is advantageously used that during operation of the internal combustion engine already characteristic signals to and / or arise in the internal combustion engine, which are suitable for determining the operating state. In particular, this does not require any additional transmitters or connections for picking up the ignition signal, which reduces costs both in terms of production and on the part of the user. According to the method, it is provided here that the ignition signal is transmitted from the internal combustion engine as an interference or noise emission, for example in the form of radio and / or sound waves, to the operating and display device.

The invention is based on the consideration that modern control and display devices, in particular smartphones or tablet computers, are widely used in today's society and a user is generally available and accessible at all times. In particular, the user of the internal combustion engine with great likelihood essentially has such an operating and display device in his household.

Modern smartphones today are still standard with a variety of different sensor and measuring systems, such as acceleration and gyro sensors, acoustic (microphone) and optical (camera) sensors or magnetic Hall sensors, equipped, whereby the ignition signal is detectable in principle in different ways , As a result, the user does not need an additional, separate measuring system for monitoring the internal combustion engine, but it is possible to use his already existing smartphone for determining and evaluating the operating state by (subsequently) downloading and / or installing the application software. In this way, user-side costs are advantageously reduced during monitoring and / or maintenance of the internal combustion engine.

The typically designed as touch screens surfaces of smartphones or tablet computers continue to allow a particularly simple and intuitive operation of the application software of the operating and display device formed thereby. As a result, a smartphone or tablet computer can be retrofitted in a particularly cost-effective manner for monitoring the internal combustion engine. In a preferred embodiment, by means of the application software in particular the current operating state or a time profile of the monitored operating state can be displayed on a display unit of the operating and display device. The display unit is typically the display or the touchscreen of the smartphone.

The internal combustion engine is designed as a hand-held or hand-held working device and in particular has a (cutting) tool driven by the internal combustion engine. The tool is designed, for example, as a rotating knife or the like, wherein the implement is, for example, a lawnmower or a brushcutter. Alternatively, the implement is a power cutter, a chainsaw or a hedge trimmer, the tool being adapted and configured accordingly.

In a preferred embodiment, a speed of the internal combustion engine is determined as the operating state. This makes it possible to use in an embodiment of the application software, the operating and display device for setting and maintenance of a carburetor of the internal combustion engine. Thus, no additional tachometer or tachometer are needed for this purpose.

In an expedient embodiment, the operating state, in particular the rotational speed of the internal combustion engine, is determined on the basis of a time interval between two successive ignition signals. The pulse-shaped ignition signals occur in each case with an ignition of the ignition device, whereby from the time interval between two such ignition signals in a simple manner, the (ignition) spark repetition rate and thus the speed or speed curve of the engine can be determined.

The device according to the invention for carrying out the method according to the invention described above essentially comprises the internal combustion engine and the operating and display device. In an expedient embodiment, the operating and display device in this case has a first sensor system for receiving the ignition signal and a controller which is set up by the program to evaluate the ignition signals. As a result, a particularly cost-effective integration solution for the process is realized.

The internal controller of the operating and display device is formed at least in the core by a microcontroller with a processor and a data memory, in which the functionality for implementing the method in the form of application software is implemented programmatically, so that the method or the determination of the operating state - if necessary in interaction with the user - when running the application software in the microcontroller is performed automatically.

In a suitable embodiment, the ignition signal to an electromagnetic signal component, which inductively coupled to the first sensor system. The electromagnetic signal component is, in particular, a high-frequency signal which arises at the time of the spark in an ignition cable or a spark plug of the ignition device. The signal component is radiated on the ignition cable in the manner of a transmitter or an antenna as an alternating electromagnetic field (electromagnetic wave, radio wave).

In a preferred embodiment, the first sensor system is designed here in particular as an electronics of the operating and display device. The electronics expediently has a number of printed conductors, which act as receivers for the electromagnetic signal component of the ignition signal.

In this case, the fact is advantageously used that operating and display devices according to the invention such as smartphones or tablet computers have comparatively complex electronic circuits in which the electromagnetic interference pulse of the signal component induces a voltage on the lines of the circuits. Each line section or each track acts as an antenna or a receiver due to the relatively high intensity of this interference. In this case, it is conceivable, for example, for the induced voltages to put one or more input or differential amplifiers of the electronics in an error state, since, for example, their common-mode suppression is disturbed or corresponding maximum permissible signal levels are exceeded.

By evaluating and analyzing these voltages and / or the error states occurring thereby, a detection of the electromagnetic signal component of the ignition signal is thus made possible in a structurally particularly simple manner. In particular, no additional sensor or measuring systems of the operating and display device are needed, but only the always existing electronics. Since the internal combustion engine is subject to corresponding EMC guidelines, it is always ensured that the electronics are not permanently damaged in the event of such a disturbance or influence by the electromagnetic signal component.

Additionally or alternatively, it is also conceivable, for example, that the electromagnetic signal component is received by means of a radio or radio receiver as the first sensor system. The radio receiver converts the analogue electromagnetic signal component into a digital signal. This digital signal is then evaluated by means of the controller or the application software.

In an advantageous development, the ignition signal to an acoustic signal component, which is transmitted in parallel to the electromagnetic signal component of the internal combustion engine. The acoustic signal component is receivable with a second sensor system, in particular with a microphone, of the operating and display device. Under the acoustic signal component is in this case in particular a triggered by the spark noise in the combustion tract or the combustion chamber of the internal combustion engine to understand, which is transmitted via the ambient air as a sound wave. In other words, the acoustic signal component is not the (continuous) engine noise that arises due to normal engine operation or engine revolutions. Rather, the acoustic signal component is due to the relatively high temperature rise and consequent mixture expansion during combustion of the air-fuel mixture in the combustion chamber. This means that the acoustic signal component - similar to the electromagnetic signal component - is a pulse-shaped interference signal. The corresponding sound waves can then be received by a microphone.

Smartphones as operating and display devices have functionally microphones and corresponding converter modules for digital processing of the audio signal of the acoustic signal component. The application software in this case preferably analyzes the audio signal and determines from this the spark or combustion repetition rate. From this repetition rate, the rotational speed of the internal combustion engine can then be determined as the operating state.

For the purpose of the most accurate and reliable determination of the operating state, it is provided in an advantageous embodiment that the controller or the application software installed thereon jointly evaluate the electromagnetic signal component and the acoustic signal component.

An embodiment of the invention will be explained in more detail with reference to a drawing. In it show in simplified and schematic representations:

1 a device for monitoring an internal combustion engine with an operating and display device,

2 an ignition device of the internal combustion engine,

3 the control and display unit with internal electronics with sensor systems, and

4 a timing diagram of an ignition signal generated by the ignition device.

Corresponding parts and sizes are always provided with the same reference numerals in all figures.

In the 1 is a device 2 for monitoring an internal combustion engine 4 shown. The fragmentarily shown internal combustion engine 4 is in this embodiment, a hand-held or hand-held implement such as a chainsaw or a lawnmower. The internal combustion engine 4 has for this purpose, not shown in detail (cutting) tool, which by means of an internal combustion engine 6 is driven.

The internal combustion engine 6 is in particular a two-stroke engine with one in a combustion chamber 8th drive-technically mounted engine pistons 10 , An air-fuel mixture is produced by means of a carburettor 12 inlet side into the combustion chamber 8th directed. During the first stroke, the mixture is caused by an upward movement of the engine piston 10 compressed and shortly before the dead center of the internal combustion engine 6 by means of a spark plug 14 an ignition device 16 ignited. This will cause the engine piston 10 pressed down in the second bar, creating an outlet 18 is released to the outflow or discharge of the formed exhaust gas.

In the block diagram of 2 is the ignition device (magnet or capacitor ignition device) 16 with a magnet generator 20 shown. The magnet generator 20 has a pole wheel 22 with a magnet with north and south pole N, S on, which is synchronous with the internal combustion engine 6 the internal combustion engine 4 rotates. The magnet generator 20 is with an ignition module 24 coupled, which by means of an ignition cable 26 to the spark plug 14 the combustion chamber 8th is contacted.

During rotation, this is induced by means of the magnetic generator 20 generated magnetic field - reinforced by an iron core 28 - A voltage or a current in a charging coil 30 and optionally in a further coil winding or trigger coil 32 as well as in a frequently also referred to as an ignition transformer, ignition generator or ignition coil ignition transformer 34 of the ignition module 24 ,

The ignition transformer 34 has a primary winding 36 as well as a secondary winding 38 on. About as a rectifier 40 acting diode become the positive half-waves of a charging voltage (charging current) of the charging coil 30 to a hereinafter also referred to as ignition capacitor energy storage 42 guided. The positive half-waves of the charging voltage charge the ignition capacitor 20 above the primary winding (primary coil) connected in series, for example to earth or ground, in series 36 of the ignition transformer 34 on.

About the charging coil 30 - according to the in 2 dashed lines shown signal line - or optionally via the trigger coil 32 is a power supply (power supply) 44 for a controller 46 in the form of preferably a microprocessor or microcontroller energetically supplied with a charging voltage FV _DD . The power supply 44 generates on the basis of the charging voltage FV _DD a supply voltage V _DD , and provides the supply voltage V _DD for the controller 46 ready.

The controller 46 has a control output 48 which is connected to a control connection (base, gate) of an electronic semiconductor switch (ignition switch) 50 connected. About the control output 48 is from the controller 46 on the ignition switch 50 actuated ignition pulse S _{Z sent} for control. Upon actuation of the ignition switch 50 becomes the ignition capacitor 42 over the primary winding 36 of the ignition transformer 34 discharged and subsequently through the secondary winding 38 of the ignition transformer 34 generates a high voltage pulse S _V. This high voltage pulse S _{V in} turn causes a spark plug 30 the internal combustion engine a sparkover to ignite the mixture.

The ignition device 16 is still with a switch connection 52 a stop switch 54 contacted or contacted. The switch connection 52 is a signal connection 56 of the controller 46 assigned. Furthermore, the controller points 46 a signal or synchronization input 58 as a connection. At this a voltage or synchronization signal S _{1 is performed} , between the ignition capacitor 42 and the primary winding 36 of the ignition transformer 34 is tapped.

Alternatively, the synchronization signal S ₁ - corresponding to one in the 2 dashed lines signal line - on the possibly existing trigger coil 32 tapped and to a synchronization input 58 ' of the controller 46 guided. Additionally or alternatively, it is also conceivable that the synchronization signal S ₁ - as in the 2 represented by a dashed signal line - as a charging voltage FV _DD to the power supply 44 is guided.

To detect the through the charging coil 30 Generated charging coil voltage assigns the controller 46 also a connection 60 on. The charging coil voltage is between the charging coil 30 and the rectifier 40 tapped and to the connection 60 guided.

Upon ignition of the ignition device is a pulse-shaped ignition signal 62 ( 4 ) generated by the internal combustion engine 4 is emitted as an interference or noise emission to the environment. The device 2 points to the monitoring of the internal combustion engine 4 a mobile operating and display device 64 on which the ignition signal 62 receives and evaluates.

The ignition signal 62 has in this embodiment essentially two signal components 62a and 62b on. When guiding the high-voltage pulse S _V through the ignition cable 26 becomes the signal component 62a as a high-frequency electromagnetic wave (radio wave) from the ignition cable 26 radiated in the manner of a transmitter antenna. The signal component 62b arises as an acoustic signal (sound wave) during combustion of the mixture within the combustion chamber 8th ,

In the embodiment, the distance between the internal combustion engine 4 and the operating and display device 64 preferably small enough that the signal components 62a and 62b have no significant transit time differences at a reception. In other words, the signal components 62a and 62b substantially parallel to each other from the internal combustion engine 4 sent out and essentially simultaneously from the control and display device 64 receive.

At the in 3 schematically illustrated operating and display device 64 it is in particular a smartphone. The smartphone 64 has a touch-sensitive display unit 66 on, which is also referred to below as a touch screen. Conveniently, the smartphone 64 in a transmission range of the interference or the ignition signal 62 introduced and typically up to a few inches to the internal combustion engine 4 approximated. The signaling connection between the smartphone 64 and the internal combustion engine 4 takes place here via the interaction of the interfering radiation 62 with integrated electronics 68 of the smartphone 64 ,

The Electronic 68 comprises a number of sensor or measuring systems, wherein in the 3 an example of a microphone 70 , a radio or radio antenna 72 and a Hall sensor 74 are shown. The sensor systems 70 . 72 and 74 are in signal technical contact with a controller 76 , The controller 76 is essentially a microcontroller with an implemented application software 78 for program technical evaluation of the ignition signals 62 educated. The application software 78 is preferably a mobile app or a smartphone app in a data memory of the controller 76 is deposited. The controller 76 represents the application software 78 on the touch screen 66 where the application software 78 by means of the touch-sensitive surface of the touchscreen 66 is operated by a user.

The radio or radio antenna 72 as well as the Hall sensor 74 are in principle for the reception of the signal component 62a furnished and suitable. Preferably, the signal component becomes 62a however by means of the electronics 68 or received by means of their conduction paths or conductor track sections. The Electronic 68 itself is thus at least in terms of the signal component 62a as a sensor or measuring system to understand.

The Electronic 68 is designed as a comparatively complex circuit, wherein the electromagnetic interference pulse of the incident signal component 62a on the wires of the electronics 68 induces a voltage. The signal component 62a has compared to the power of the switching elements of the electronics 68 a comparatively high intensity, so that substantially each trace as a receiving antenna for the signal component 62a acts. The induced voltage has a corresponding to the internal supply voltage of the electronics 68 comparatively high voltage potential. This causes the induced voltage, for example, differential amplifier units 78 the electronics 68 in an error condition, since their common-mode rejection is disturbed or corresponding maximum permissible signal levels are exceeded. The differential amplifier units 78 are part of the sensor systems, for example 70 . 72 and 74 or part of other unspecified electronic circuits of the electronics 68 ,

The acoustic signal component 62b is essentially simultaneously using the microphone 70 added. By appropriate converter modules of the electronics 68 becomes the signal component 62b for digital processing to the controller 76 Posted. Based on the received signal components 62a and 62b or based on the optionally generated thereby error messages of the electronics 68 becomes the ignition signal 62 evaluated with the application software.

An exemplary course of the smartphone 64 received ignition signal 62 or the received signal components 62a and or 62b is in the 4 shown. The schematized signal curves are hereby plotted along an abscissa axis as time axis t and an ordinate axis as signal amplitude axis A. Like in the 4 comparatively clear are the received ignition signals 62 each separated by a time interval .DELTA.t from each other.

The application software 78 is suitable and set up, from the time interval .DELTA.t two ignition signals 62 , or the change and / or the course of the time interval .DELTA.t over a number of received ignition signals 62 , the spark or combustion repetition rate of the internal combustion engine 6 during operation of the internal combustion engine 4 to determine. From this repetition rate determines the application software 78 then the speed of the internal combustion engine 6 as the operating state of the internal combustion engine 4 ,

As a result, it is a user of the internal combustion engine 4 in a simple way allows his smartphone 64 for determining or monitoring the rotational speed of the internal combustion engine 6 by downloading and installing the application software 76 retrofit. In other words, it is possible for the user, for example, his smartphone during adjustment or adjustment of the carburetor 12 use.

The invention is not limited to the embodiment described above. On the contrary, other variants of the invention can be derived by the person skilled in the art without departing from the subject matter of the invention. In particular, all the individual features described in connection with the exemplary embodiment can also be combined with each other in other ways, without departing from the subject matter of the invention.

For example, it is conceivable that the operating and display device 64 designed as a tablet computer.

LIST OF REFERENCE NUMBERS

2

contraption

4

Internal combustion engine

6

internal combustion engine

8th

combustion chamber

10

piston

12

carburettor

14

spark plug

16

detonator

18

outlet

20

magnet generator

22

flywheel

24

ignition module

26

ignition cable

28

iron core

30

charging coil

32

trigger coil

34

ignition transformer

36

primary

38

secondary winding

40

rectifier

42

Energy storage / ignition capacitor

44

power supply

46

controller

48

control output

50

Ignition switch / semiconductor switch

52

switch connection

54

stop switch

56

signal connection

58, 58 '

Signal input / sync input

60

connection

62

Ignition signal / interference

62a, 62b

signal component

64

Operating and display device / smartphone

66

Display unit / Touchscreen

68

Electronics / sensor system

70

Microphone / sensor system

72

Radio antenna / radio antenna / sensor system

74

Hall sensor / sensor system

76

controller

78

Differential amplifier unit

N

North Pole

S

South Pole

FV _DD

charging voltage

V _DD

supply voltage

S _Z

ignition pulse

S _V

High voltage pulse

S ₁

Voltage signal / synchronization signal

t

timeline

A

Signal amplitude axis

.delta.t

lag

Claims (9)

Method for monitoring a hand-held or hand-carried internal combustion engine ( 4 ) with an internal combustion engine ( 6 ) and an ignition device coupled thereto ( 16 ), Wherein at ignition of the ignition device ( 16 ) a pulse-shaped ignition signal ( 62 ), which leads to a mobile operating and display device ( 64 ), in particular a smartphone, is transmitted, - in the operating and display device ( 64 ) an application software ( 78 ), with which a number of chronologically successive ignition signals ( 62 ) for determining an operating state of the internal combustion engine ( 4 ), and - the ignition signal ( 62 ) an operating signal of the internal combustion engine ( 4 ), which is transmitted to the operating and display device ( 64 ) is transmitted. Method according to Claim 1, characterized in that the ignition signal ( 62 ) of the internal combustion engine ( 4 ) as an interference to the operating and display device ( 64 ) is transmitted. Method according to Claim 1 or 2, characterized in that a rotational speed of the internal combustion engine ( 6 ) is determined. Method according to one of claims 1 to 3, characterized in that the operating state, in particular the rotational speed of the internal combustion engine ( 6 ), based on a time interval (Δt) between two consecutive ignition signals ( 62 ) is determined. Contraption ( 2 ) for carrying out the method according to one of claims 1 to 4, characterized in that the operating and display device ( 64 ) a first sensor system ( 68 . 72 . 74 ) for receiving the ignition signal ( 62 ) as well as a controller ( 76 ), which programmatically for the evaluation of the ignition signals ( 62 ) is set up. Contraption ( 2 ) according to claim 5, characterized in that the ignition signal ( 62 ) an electromagnetic signal component ( 62a ) inductively connected to the first sensor system ( 68 ) couples. Contraption ( 2 ) according to claim 6, characterized in that the first sensor system ( 68 ) an electronics of the operating and display device ( 64 ), which has a number of tracks which serve as receivers for the electromagnetic signal component ( 62a ) Act. Contraption ( 2 ) according to one of claims 5 to 7, characterized in that the ignition signal ( 62 ) an acoustic signal component ( 62b ) provided with a second sensor system ( 70 ), in particular with a microphone, the operating and display device ( 64 ) is receivable. Contraption ( 2 ) according to claim 8, characterized in that the controller ( 76 ) for determining the operating state, the electromagnetic signal component ( 62a ) and the acoustic signal component ( 62b ) evaluates together.

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