Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
  • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
  • F02D41/263—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor the program execution being modifiable by physical parameters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/009—Electrical control of supply of combustible mixture or its constituents using means for generating position or synchronisation signals

Definitions

• the invention relates to a method and a device for recording analog signals, in particular analog sensor signals, which are related to an angle signal, in particular the angle signal of a crankshaft in internal combustion engines.
• Devices and methods of this type are used primarily for recording analog measured values in engine control units (Engine Control Units, ECus).
• ECU engine control unit
• AD converters analog-digital converters
• filter modules electronic filter modules
• the engine control unit uses the numerous sensor signals (for example with the aid of tables, so-called look-up tables) to calculate the corresponding control signals and setting parameters, such as, for example, the optimal timing of an ignition or the optimal duration of a fuel injection.
• analog measured values for example the measured values from pressure, temperature or oxygen sensors
• the time synchronization of the measurement plays a significant role.
• Simple computer systems also contain internal clock systems (clock), which can basically be used for the time acquisition and synchronization of the measurement value acquisition.
• clock internal clock systems
• the measured values typically have to be recorded in relation to a defined operating state of the engine.
• the crankshaft's angular position has established itself as an indicator of the operating state of an engine.
• the angular position of the crankshaft exactly defines the position of the pistons in each individual cylinder.
• a complete cycle of a typical four-cylinder internal combustion engine comprises two complete revolutions of the crankshaft, i.e. angles from 0 ° to 720 °. After two revolutions (720 °), each cylinder of the engine has completed its cycle once.
• the cylinders work sequentially, which means that each cylinder only works within a certain section within a complete cycle.
• Such a time period is also referred to as a segment.
• Each segment corresponds to a range of the angular position of the crankshaft, which results from the entire angular range (for example 720 °) divided by the number of cylinders.
• a segment of a four-cylinder internal combustion engine has an angular range of 180 °. The first segment corresponds to angular positions from 0 ° to 180 °, the second angular positions from 180 ° to 360 ° etc.
• the angular position of the crankshaft is typically detected by means of a so-called encoder disk on the crankshaft.
• This encoder disk is usually a metallic toothed disk, the rotation of which is usually detected by means of an inductive sensor.
• Typical encoder disks for four-cylinder engines for example, have 60 teeth (or 58 after deducting the two "tooth gaps"), which corresponds to a number of 120 teeth for a complete cycle of 720 °, ie one tooth per 6 ° angular position.
• the magnetic field in the coil changes, as a result of which a current is induced in the coil.
• the frequency of this time-varying current is a measure of the speed of the crankshaft.
• Other types of sensors such as optical or magnetic sensors, can also be used in principle.
• gaps are usually built into the teeth of the encoder disk, the gaps typically comprising two teeth. In this way, the position of the crankshaft and thus an important parameter of the operating state of the internal combustion engine can be exactly determined on the basis of the signal.
• the angular position of the crankshaft or the speed is synchronized in conventional engine control units at regular intervals with the internal clock of the engine control unit.
• the detection of sensor signals and the calculation or generation of corresponding parameters and control signals based thereon takes place as a function of the internal clock of the engine control unit.
• the angular position of the crankshaft must first be recorded at a specific engine speed and synchronized with the internal clock of the engine control unit. Then, measurement data of the various sensors are recorded relative to the internal clock of the engine control device. This measurement data acquisition has hitherto usually been carried out at a fixed sampling rate, with sampling rates between 5 and 10 microseconds being typical. For example, a new analog value of a specific sensor signal is recorded every 10 microseconds.
• Optimal control signals are then calculated from these measurement data, which, however, have to be output, for example, in precisely defined angular positions of the crankshaft (for example calculated by the engine control unit).
• the optimal times in the time base of the engine control device must be calculated and then in turn converted into corresponding angular positions.
• This complex calculation and generation of control signals places an extreme strain on the microprocessor of the ECU, which typically only has a clock frequency of 40 MHz and a memory capacity of 256 kilobytes.
• the object of the invention is therefore to specify a method and a device by means of which the acquisition and processing of analog measurement data in engine control devices is improved. This object is achieved by the invention with the features of the independent claims. Advantageous developments of the invention are characterized in the subclaims.
• An engine control device which has means for detecting an angular position of a crankshaft, and means for converting the angular position of the crankshaft into an electronic trigger signal. Furthermore, the engine control device should have means for detecting at least one analog signal, in particular an analog sensor signal, including at least one signal input for analog signals, at least one analog-digital converter for converting the at least one analog signal into at least one digital signal and at least one control device , Depending on the electronic trigger signal, this control device should be able to switch the detection of the at least one analog signal on or off and / or to start or stop it.
• capture is to be interpreted broadly. For example, I can measure, store (sample), convert analog-to-digital, save or a combination of these processes (possibly with further modifications of the signals). Alternatively, a permanent analog-to-digital conversion can also take place, with only the storage of the converted data being understood as “recording”. Accordingly, “means for detection” can be understood to mean, for example, a corresponding sensor, an analog-to-digital converter, a corresponding signal conversion or intermediate storage, or even only a part of these devices.
• the control device can be, for example, a trigger input, which in particular has means for generating a trigger signal, e.g. B. a trigger converter can interact.
• An engine control device is to be understood as a system for controlling an internal combustion engine. This does not necessarily have to be a physical and / or electronic unit, but in particular it can also be a combination of interacting, but spatially separated components.
• the means for converting the angular position of the crankshaft into an electronic trigger signal and the means for detecting the at least one analog signal can be wholly or partly integrated in an integrated electronic circuit, in particular a so-called application-specific integrated circuit (ASIC).
• ASIC application-specific integrated circuit
• the digital electronic trigger signal can in particular be a periodic, for example rectangular, signal, for example a TTL signal.
• a period of this signal can correspond to a period on the encoder disk, that is to say the distance between two teeth on the encoder disk (see above) or the resulting angular rotation of the crankshaft.
• one period corresponds to an angular rotation of the crankshaft of 6 °.
• an absolute angular position of the crankshaft can also be inferred from the corresponding gaps in the trigger signal.
• the trigger signal can also be modified accordingly.
• An adjustment of the signal level, frequency filtering, frequency multiplication and / or a phase shift has proven to be particularly advantageous.
• Frequency filtering may be necessary, for example, in order to eliminate higher-frequency or low-frequency interference signals (vibrations, harmonics, etc.).
• Under frequency multiplication is a modification of a periodic one
• a multiplier which is typically a rational number, in particular a natural number between 0 and 1 or greater than 1).
• the conversion of the trigger signal into a new trigger signal by means of a predetermined function is also conceivable.
• a predetermined number for example, a predetermined by a computer program
• a trigger signal can be generated, which assumes the value "high” only in very specific angular positions of the crankshaft.
• the signal "high” can be output for a predetermined period of time.
• the modification of the trigger signal can be adapted to the speed of the crankshaft.
• a frequency multiplication of a trigger signal periodic with a frequency F can take place in such a way that the frequency F of the new trigger signal increases less than proportionally with the rotational speed D.
• the quotient of frequency F and speed D decreases with increasing speed.
• This sinking does not have to take place continuously, but can also take place, for example, in discrete steps. If the acquisition of analog measurement data is controlled with this new trigger signal (see below), this targeted adaptation of the frequency multiplication can be used to ensure that the storage and / or computing capacity of the engine control unit is constantly loaded per unit of time over the entire speed range.
• the trigger signal can be adapted to the speed while the engine control unit is running.
• the conversion of the angular position of the crankshaft into a corresponding trigger signal according to one of the described Driving can in particular also be purely hardware-based, that is to say take place in separate electronic modules without the use of computing algorithms.
• the use of a microprocessor or an additional load on the processor capacity of an existing processor (see below) through the formation of the trigger signal is thereby avoided.
• the at least one analog signal can in particular be an analog signal from a sensor, for example an oxygen, temperature or pressure sensor, and it is also possible to detect a plurality of analog signals, in particular the signals from a plurality of sensors.
• a sensor for example an oxygen, temperature or pressure sensor
• the use of one or more switches, which can switch the detection between the individual analog signals is particularly suitable.
• the signals of a plurality of sensors can be recorded in succession or alternatively or in parallel.
• the switchover between the detection of the individual signals can be controlled in particular by a microcomputer, so that the analog signals of predetermined sensors are detected at predetermined times.
• the switchover can also be controlled by the electronic trigger signal (which can also consist of several correlated individual signals).
• the means for detecting the at least one analog signal can also have a device for data processing (in particular a microprocessor) and means for adapting or changing the analog signals, in particular means for frequency filtering.
• a device for data processing in particular a microprocessor
• the microcomputer can be the computing unit (for example a CPU with a memory) of a commercial integrated circuit for motor control.
• the control device can in particular be a trigger input of the analog-digital converter or else act as a trigger input of the device for data processing.
• This trigger input is connected to the means for converting the angular position of the crankshaft into an electronic trigger signal.
• This does not necessarily have to be a physical electronic connection, but also, for example, a wireless connection (e.g. infrared data transmission) is conceivable.
• the trigger signal described above, generated from the angular position of the crankshaft, or a trigger signal derived therefrom is used for controlling the detection of the analog signals.
• the digitized signals can then be processed further by means of the data processing device.
• appropriate control signals for the engine control can be generated and output from a large number of sensor signals with the aid of stored functions and parameters.
• the engine control device described with the crankshaft-synchronously triggered data acquisition has, compared to the conventional engine control devices described above with a constant or predetermined sampling rate, the decisive advantage that the detection of the at least one analog signal does not take place at predetermined times with fixed predetermined repetition rates (sampling rates). Excessive load on the computing and storage capacity of the engine control unit, especially at low speeds. is prevented. Rather, the analog signals are recorded as a function of the actual angular position of the crankshaft and thus the actual operating state of the internal combustion engine.
• certain sensor signals can only be at the times that are actually interesting (for example, only in segment 2 in which the second cylinder operates, e.g. in the angular range of the crankshaft between 180 ° and 360 °) are recorded.
• Uninteresting data i.e. analog signals in angular positions of the crankshaft, which are of no interest with regard to, for example, a specific sensor, are therefore not recorded in the first place, as a result of which the memory and processor load is greatly reduced.
• a processor capacity and memory-intensive conversion of the angular position of the crankshaft or the speed into an internal time system of the engine control device can be omitted. Only hardware is required to generate the trigger signals, no software effort. The processor is thus relieved. There is also no constant high load at low speeds.
• the accuracy of the system is also significantly increased by the measurement data acquisition synchronized with the crankshaft.
• the acquisition of the measurement data can take place at predefined angular positions, which is considerably more precise than a time-controlled acquisition with subsequent interpolation that may be required.
• the sampling rate can also be adjusted, as described above, or the measurement data can be reduced with increasing speed by appropriately adapting the trigger signal to the speed. In this way, a uniform amount of data and processor load can be achieved over the entire speed range.
• preprocessing of the raw data can also take place in the analog-digital converter, which converts the analog signals from, for example, one or more sensors into digital signals.
• Such preprocessing can in particular be a frequency filter Include and / or a statistical analysis of the analog or already digitized data. For example, the data can already be averaged over a certain period of time or over a certain number of measured values. This preprocessing considerably reduces the amount of data that is transmitted from the analog-digital converter to the microprocessor, for example.
• crankshaft-synchronous triggering of the acquisition of the analog data according to one of the methods described above again represents an essential advantage in the preprocessing of the recorded data Contains crankshaft, for example, the analog or digital signal can be averaged directly over a certain angular range of the crankshaft. It is no longer necessary to convert the angular positions into temporal signals.
• Speed-dependent preprocessing of the data is also conceivable, for example by shifting the time or angular position range over which an analog or digital signal is averaged depending on the speed.
• the timing of the ignition can depend heavily on the engine speed. It may be of interest to record, for example, the pressure in a specific cylinder, averaged in a specific angular range, relative to the ignition time.
• a predefined approximation function can also be adapted to the recorded data, for example. Accordingly, instead of the data, for example, only the sewing seam will then become tion function or the parameters characterizing the approximation function from the analog-digital converter to the device for data processing.
• the information about the angular position or the rotational speed of the crankshaft can also play a role here, for example as one of the parameters of the approximation function.
• This type of preprocessing of the signals also contributes significantly to the reduction of the required processor and memory capacity.
• Another advantage of the motor control device described is the fact that the device can be implemented with existing microprocessors and electronic components. Both microprocessors with trigger input for motor control devices and analog-digital converters with trigger input are commercially available. An expensive and complex new development of such components is not necessary.
• a method for crankshaft-synchronous detection of analog signals, in particular analog sensor signals, is also proposed, in which the angular position of a crankshaft is first detected.
• the detected angular position of the crankshaft is converted into at least one electronic trigger signal.
• at least one analog signal, in particular an analog sensor signal is recorded.
• the at least one analog signal is converted into at least one digital signal.
• the acquisition and / or the analog-digital conversion of the at least one analog signal is controlled by means of the trigger signal.
• the acquisition and / or analog-digital conversion of the at least one analog signal is advantageously controlled using one of the following principles or a combination of these principles: -
• the detection and / or the analog-digital conversion is triggered in that the trigger signal reaches, exceeds or falls below a predetermined level.
• the detection and / or the analog-digital conversion is made possible as long as the trigger signal at least reaches and / or exceeds a predetermined signal level, otherwise the detection and / or analog-digital conversion is prevented.
• the detection and / or the analog-digital conversion is made possible as long as the trigger signal falls below and / or does not exceed a predetermined signal level, otherwise the detection and / or analog-digital conversion is prevented.
• the detection and / or the analog-digital conversion is made possible with a periodic trigger signal for a predetermined number of periods and is otherwise prevented.
• the detection and / or the analog-to-digital conversion is made possible and otherwise prevented from a predetermined trigger signal, in particular from a point in time at which the trigger signal reaches, exceeds or falls below a predetermined level.
• the level of the at least one analog signal can also be changed and / or frequency filtering of the at least one analog signal can be carried out.
• at least one control signal for controlling an internal combustion engine can be calculated from the at least one digital signal by means of a data processing algorithm.
• the at least one electronic trigger signal can be frequency multiplied by a predetermined multiplier and / or be phase shifted by a predetermined phase and / or at least one second electronic trigger signal from the at least one electronic trigger signal Trigger signal are generated, wherein the second electronic trigger signal is a function with variable parameters of the first electronic trigger signal.
• the generation of the at least one electronic trigger signal can be dependent on the speed of the crankshaft. If the electronic trigger signal is periodic with a frequency F or is approximately periodic or is at least approximately periodic within a period of time considered, the frequency F is multiplied as the speed increases such that the ratio between the frequency F and the speed is advantageous D decreases with increasing speed D.
• FIG. 1 shows a first embodiment of an engine control device with a microcomputer triggered by crankshaft synchronism for measurement data acquisition;
• FIG. 4 shows a flow chart of a first exemplary embodiment of a method for crankshaft-synchronous measurement data acquisition
• FIG. 5 shows a flowchart of a second exemplary embodiment of a method for crankshaft-synchronous measurement data acquisition
• FIG. 6 shows a second embodiment of an engine control device with an external AD converter triggered by crankshaft synchronism for measurement data acquisition.
• the core element of the motor control device 110 in FIG. 1 is an integrated circuit (ASIC) 112, which comprises a trigger converter 114 and a fast AD converter (FADC) 116.
• ASIC 112 is a controller of the TC17xx family from the manufacturer Infineon.
• a signal output 118 of the trigger converter 114 is connected to a trigger input 120 of the FADC 116.
• a crankshaft sensor 122 is connected via a crankshaft AD converter 124 to a signal input 126 of the trigger converter 114.
• a temperature sensor 128 is connected via a filter amplifier unit 130 to a signal input 132 of the FADC 116.
• crankshaft signal 134 exchanged between crankshaft AD converter 124 and trigger converter 112 is shown in FIG. 2.
• the trigger signal 136 exchanged between the trigger converter 112 and the FADC 116 is shown in FIG. 3.
• the crankshaft sensor 122 detects a signal from the crankshaft, which in this example is an analog sine signal (not shown) from a magnetic sensor which detects the position of the teeth of the toothed disk described above.
• This analog sine signal is converted in the crankshaft AD converter 124 into the crankshaft signal 134 shown in FIG. 2.
• This is a square-wave signal, which is at the "Low” level (here the zero line) for a period of time t1 to t2, and then at the "High” TTL level (5 volts) for a period of time from t2 to t3.
• the signal therefore has a period t3-tl and a frequency of l / (t3-tl).
• the crankshaft signal 134 is frequency multiplied in the trigger converter 114 by a factor of nine. Accordingly, the trigger converter 114 generates a square wave signal with the frequency 9x1 / (t3-tl) from the crankshaft signal 134 as the trigger signal 136. In this example, the signal levels are left unchanged.
• the trigger converter 114 starts the conversion in each case at the time t1, that is to say with a falling edge of the crankshaft signal 134, and generates a rising edge of the trigger signal 136. Accordingly, the trigger signal 136 is phase-shifted by 180 ° compared to the crankshaft signal 134.
• This trigger signal 136 is forwarded to the FADC 116 via the signal input 120.
• the trigger input 120 is configured in such a way that the FADC 116 only accepts signals at its signal input 132 if the trigger signal 136 exceeds a predetermined level. The rest of the time, the FADC 116 "ignores" signals at its signal input 132.
• step 410 the crankshaft signal is detected, digitized in the crankshaft AD converter 124, and then converted in step 412 in the trigger converter 112 into the trigger signal 136. This is then forwarded in step 414 to an analog-to-digital converter, here specifically the FADC 116.
• step 416 FADC 116 queries whether the trigger signal exceeds a predetermined value. This query can take place in a permanent loop. Only if this is the case is an analog signal, which is forwarded from the filter amplifier unit 130 to the FADC 116 in the example shown in FIG. 1, recorded in step 418 and converted into a digital signal in step 420.
• step 422 then forwards further processing to a microprocessor (not shown in FIG. 1), which can generate, for example, control signals for motor control from this signal in accordance with its programmed algorithms.
• FIG. 5 shows an analog method in which the trigger signal 136 is not used to trigger an AD converter, but rather to trigger the data acquisition by a microprocessor.
• This microprocessor which is part of practically every motor control device, is not shown in FIG. 1. It can be a further component of the ASICS 112.
• the angular position of the crankshaft is first detected in step 510 and converted into a trigger signal in step 512.
• this trigger signal is then not forwarded directly to an AD converter, but to a microprocessor.
• the latter queries the trigger signal in step 516 and accepts no data from the AD converter as long as it does not exceed a predetermined level (step 518).
• an AD converter continuously acquires analog measurement data from one or more sensors in step 520, possibly undertakes preprocessing, converts the analog signals into digital signals and makes the converted signals available to the microprocessor.
• the query in step 516 determines a sufficient trigger level does the microprocessor accept this data in step 522 and process it further in step 524.
• FIG. 6 shows an alternative construction of an engine control device 110 to FIG. 1, in which the crankshaft-synchronous trigger signal 136 is not used for triggering an internal FADC 116, but for triggering an external AD converter 610 6 is that the signal output 118 of the trigger converter 114 is connected to a trigger input 612 of the external AD converter 610. This in turn is connected via an interface 614 to a microprocessor 616 integrated in the ASIC 112.
• the function of the structure shown in FIG. 6 corresponds to the structure in FIG. 1.
• the AD conversion of the analog signal generated by the sensor 128 does not take place in the ASIC 112, but rather through the external electronic component 610.
• the analog or Already digitized data can take place in the external AD converter 610, so that the data transmitted to the microprocessor 616 via the interface 614 can already be reduced to an absolute minimum. This further relieves the load on the microprocessor 610. Since the external AD converter 610 is easily accessible, it can also be easily replaced and, for example, replaced when more modern components are available.
• the trigger signal 136 is forwarded to an AD converter in step 414 via an external line connection.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Recording Measured Values (AREA)

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• 2004
  • 2004-06-16 DE DE102004029065A patent/DE102004029065A1/de not_active Withdrawn
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  • 2005-06-15 EP EP05754119A patent/EP1756412B1/fr active Active
  • 2005-06-15 CN CN2005800200257A patent/CN1969117B/zh active Active
  • 2005-06-15 AT AT05754119T patent/ATE477411T1/de active
  • 2005-06-15 JP JP2007515956A patent/JP2008502839A/ja active Pending
  • 2005-06-15 WO PCT/EP2005/052771 patent/WO2005124134A1/fr active Application Filing
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