SIGNAL PROCESSING DEVICE AND ENGINE CONTROL DEVICE

Abstract

Signal processing device (100) that filters an output signal from a sensor mounted on a vehicle, comprising: a storage unit configured to store a relationship to a specific frequency (Pfi) of a pressure wave in a cylinder (66) corresponding to a specific frequency (Kfi) of a knock sensor signal, for each power machine operating state; and a central processing unit, CPU, (101) which is configured: to make a setting with respect to multiple filters that have different filter types or filter coefficients for setting a filter characteristic of a cutoff frequency or a passband; to set an individual code for each of the multiple filters, and to select the individual code based on a power machine operating state in such a way that a corresponding filter is selected, and to process an output signal from the sensor using the selected filter, wherein: the sensor is a knock sensor (34) that detects knocking from a power unit (65) mounted on the vehicle; and The CPU (101) is configured to calculate a knock strength (K(Kfi)) of a specific frequency of a knock sensor signal based on a signal processed by the filter that has been selected.

Description

Technical field

[0001] The present invention relates to a signal processing device and a power machine control device. Technical background

[0002] A filter function is used for engine control to process various sensor inputs. Among these inputs, knocking is a phenomenon in which gas in a combustion chamber is set into vibration due to the auto-ignition of unburned gas in a connecting section of the combustion chamber of an engine, and this vibration is transmitted to the main body of the engine. Since not only combustion but also vibrational characteristics of the main body of the engine are involved in this phenomenon, a complex filter function is required. Knocking causes a loss of energy produced by the engine (a decrease in power), affects every part of the engine, and reduces fuel consumption. Therefore, it is desirable to avoid knocking as much as possible, and for this purpose, it is essential to accurately detect its occurrence.

[0003] For example, a conventional method, disclosed below in PTL 1, is known, wherein the method comprises: separating only a single resonant frequency component in the range of 5 to 12 kHz from an output signal of a vibration sensor using a bandpass filter and detecting the occurrence of knocking based on whether an integrated value of the output of the separation is greater than a background level (past values ​​of output signals of the vibration sensor are subjected to weighted averaging) or not.

[0004] However, as disclosed in PTL 1, the method of detecting the occurrence of knocking using only a single resonant frequency component has the problems that the background level becomes large when the power machine is rotating at high speed, such that the occurrence of knocking cannot be accurately detected, and if the specifications of the power machine change, the resonant frequency of the knocking also changes, so that the occurrence of knocking cannot be accurately detected.

[0005] Therefore, PTL 2 below discloses a knock detection device which includes a vibration sensor which detects a vibration generated in a power machine, and a filter circuit which is connected to the vibration sensor and has several filters which have filter characteristics of different frequency bands in a knock frequency band.

[0006] A knock resonance frequency generated in a power machine varies depending on the machine's operating state. For example, the knock resonance frequency varies depending on whether the machine's speed is high or low. Therefore, highly reliable knock detection can be achieved by using multiple filter circuits with filter characteristics for different frequency bands, and by selecting the filter circuit output according to the machine's operating state.

[0007] In recent years, a method for implementing a filter circuit using a digital filter through software built into a microcomputer and a method for configuring a digital filter as a function of a microcomputer have also become known.

[0008] PTL 3 below discloses a method for eliminating a response delay caused by a delay filter used to detect a background level. In PTL 3, an operating state of the power machine is detected in accordance with the change in the power machine speed, and a knock determination threshold is corrected based on the operating state.

[0009] PTL 4 discloses a control device for an internal combustion engine that can detect engine knocking even when an extraction frequency band is switched according to an engine operating state. The device comprises a knock sensor for detecting vibrations generated in the engine and outputting a vibration detection signal, a rotation sensor for detecting the engine operating state, an SCF circuit for extracting a signal of a specific frequency band from the vibration detection signal and outputting an extracted vibration signal, a filter frequency switching section for switching an extraction frequency band of the filter section according to the engine operating state, and a knock detection section for detecting engine knocking based on the extracted vibration signal.The filter frequency switching section prevents the extraction frequency band from switching until a switching prevention period has elapsed after the extraction frequency band has been switched.

[0010] According to PTL 5, the output signal of a knock sensor is filtered using a variety of bandpass filters to extract vibration waveform components from a multitude of frequency bands. Weighting coefficients, which multiply the vibration waveform component of each frequency band, are set to decrease as the noise intensity of each frequency band increases. This process synthesizes the vibration waveform component of a multitude of frequency bands by weighting them according to the influence of the noise intensity of each frequency band. Even if the noise overlays the vibration waveform component of one of the frequency bands, it becomes possible to reduce the influence of the noise and synthesize the vibration waveform component of each frequency band. Based on the composite vibration waveform, an accurate knock determination can be performed. List of prior art patent literature PTL 1: JP S58 - 45 520 A PTL 2: JP S56 - 637 A PTL 3: JP S63 - 295 864 A PTL 4: US 2008 / 0 257 025 A1 PTL 5: US 2011 / 0 257 872 A1 Summary of the invention; Technical task

[0011] Furthermore, in recent years, in response to the need for, for example, improved fuel efficiency and exhaust gas purification performance, attempts have been made to increase the compression ratio of an engine. On the other hand, an increased compression ratio makes knocking more likely, so there is an expectation of further improved knock detection accuracy.

[0012] However, in the method for extracting multiple resonant frequency components and detecting a knock, disclosed in PTL 2, it is necessary to solve the problems as described below when the knock detection accuracy is further improved.

[0013] This means that with the refinement of knock control, knock detection with a preferred signal-to-noise ratio is required, and there is an increasing need to use multiple narrowband filters. To meet this need, several filters with increased degrees of freedom in their filter settings are used, which complicates the filter control. Then, as the number of parameters that make up the complex filter control increases, the operator setting the parameters (the filter coefficients) of the knock detection filters must perform a complex parameter adjustment, which can lead to problems such as the work becoming time-consuming and errors occurring more easily.

[0014] The present invention was made with regard to the problems described above, and one object of the present invention is to provide a signal processing device that can effectively reduce the workload of a parameter setting operator in response to an increase in parameters that form a complicated filter control. Solution to the task

[0015] The problem described above is solved by the features of the independent patent claims. Advantageous embodiments of the invention are described in the dependent claims. Advantageous effects of the invention

[0016] According to the present invention, it is possible to create an easy-to-use filter that can reduce the workload of a parameter setting operator in response to an increase in the parameters that constitute a complicated filter control.

[0017] The problems, configurations and effects other than those described above will become clear from the description of the embodiments below. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a system configuration diagram of a power machine control system equipped with a control ECU, as an embodiment of a signal processing device according to the present invention. [ Fig. 2] Fig. Figure 2 is an internal configuration diagram of the control ECU, which is located in Fig. 1 is shown. [ Fig. 3] Fig. Figure 3 is a comparative explanatory diagram of the knock intensity from a pressure sensor and the knock intensity from a knock sensor. [ Fig. 4] Fig. Figure 4 is an explanatory diagram showing a correlation between the knock intensity from the pressure sensor and the knock intensity from the knock sensor. [ Fig. 5] Fig. Figure 5 is an operating plan to explain a procedure for knock determination and knock control by an ECU in the present embodiment. [ Fig. 6] Fig. 6 is an operating procedure to explain the procedure for knock determination and knock control according to Fig. 5. [ Fig. 7] Fig. Figure 7 is an explanatory diagram of an example of filter setting control by the ECU in the present embodiment. [ Fig. 8] Fig. Figure 8 is an explanatory diagram of an example of filter setting control by the ECU in the present embodiment. [ Fig. 9] Fig. Figure 9 is an explanatory diagram of a filter selection example by the ECU in the present embodiment. [ Fig. 10] Fig. Figure 10 is an explanatory diagram of a filter selection example by the ECU in the present embodiment. [ Fig. 11] Fig. Figure 11 is an explanatory diagram of the necessity of a filter switching function for each cylinder by the ECU in the present embodiment. [ Fig. 12] Fig. Figure 12 is an explanatory diagram of a relationship between a power engine state, a number of cylinders, a knock frequency, and a filter setting by the ECU in the present embodiment. [ Fig. 13] Fig. Figure 13 is an explanatory diagram of a relationship between a power engine state, a number of cylinders, a knocking frequency, and a filter setting by the ECU in the present embodiment. [ Fig. 14] Fig. Figure 14 is an explanatory diagram of the necessity of a filter switching function for the relationship between the engine state and the knocking frequency by the ECU in the present embodiment. [ Fig. 15] Fig. Figure 15 is an explanatory diagram of a relationship between a power engine state, a number of cylinders, a knocking frequency, and a filter setting by the ECU in the present embodiment. [ Fig. 16] Fig. Figure 16 is a functional block diagram of the CPU of the ECU in the present embodiment. Description of the embodiments

[0018] One embodiment of the present invention is described in detail below with reference to the drawings. However, the present invention is not limited to the embodiment shown below, and various modifications and application examples also fall within the scope of the technical concept of the present invention.

[0019] First, a general principle of knock detection is described below as an example of signal processing in the present invention. Then, an embodiment of the present invention is described in detail.

[0020] One embodiment, which is in Fig. Figure 1 shows a so-called four-cylinder in-line engine of the multi-point injection type (MPI type).

[0021] Air drawn into a power unit 65 passes through an air purifier 60 and is directed to a hot-wire type air flow sensor 1. A heat-radiation type air flow sensor is used as the hot-wire type air flow sensor 1. A signal corresponding to the amount of intake air is output from the hot-wire type air flow sensor 1, and an intake temperature signal, measured by an intake temperature sensor 1a using a thermistor integrated into the hot-wire type air flow sensor 1, is also output. The intake air then passes through a channel 61 connected to the air purifier 60 and a throttle valve 40, which controls the air flow rate, and enters a collector 62.The throttle valve 40 is equipped with a throttle position sensor 2, which detects the degree of opening of the throttle valve 40, and the throttle valve 40 is actuated by a throttle actuator motor 41, which is controlled by an engine control unit (ECU) 100 as a signal processing device. The air that has entered the manifold 62 is distributed to each intake line 63, which is directly connected to the engine 65, and is drawn into a cylinder 66 (a combustion chamber) via an intake valve 35. A valve timing adjustment mechanism 37 with a cam angle sensor 9 is provided in the valve control system of the intake valve 35 and an exhaust valve 36 to perform feedback control to a target angle.Furthermore, crank angle sensors 4, which are attached to cylinder blocks (which are sometimes referred to below as engine blocks) 66, 67, output a pulse for each specified crank angle and these outputs are entered into the ECU 100.

[0022] The fuel is drawn from the fuel tank 21 and pressurized by a fuel pump 20, adjusted to a constant pressure by a pressure regulator 22 and fed into the inlet line 63 by the injector 23, which is provided in the inlet line 63.

[0023] By switching on / off the ignition output of a spark plug 33 at a time corresponding to the rotational speed of the engine 65, and by setting an ignition timing determined according to the load of the engine 65, ignition is initiated at an optimal time. If the ignition occurs too early, knocking occurs in the combustion chamber (in cylinder 66). Therefore, when the knock sensor 34, acting as a vibration sensor, detects a vibration of the cylinder 66 due to knocking and determines the knocking, knock control is performed to retard the ignition timing.

[0024] A throttle position sensor 2 for detecting the opening degree of the throttle valve 40 is attached to the throttle valve 40, and the sensor signal from the throttle position sensor 2 is fed into the ECU 100 to perform feedback control of the opening degree of the throttle valve 40, to detect a fully closed position, to detect acceleration, and the like. The target opening degree of the feedback is determined from the amount of accelerator pedal depressed by the driver, which is determined by an accelerator pedal depressed sensor 5, and an amount of idle speed control, i.e., the ISC control.

[0025] A water temperature sensor 3, which detects the coolant temperature, is attached to the engine 65, and the sensor signal from the water temperature sensor 3 is input into the ECU 100 to detect a warm-up state of the engine 65, increase the fuel injection quantity from the injector 23, correct the ignition timing of the spark plug 33, and set the on / off state of a radiator fan 68 and the target idle speed. An air conditioning switch 6, which monitors the state of an air conditioning clutch, an idle switch 7, which is installed in a transmission and monitors the state of the drive system, and the like are attached to the engine 65 to calculate the target idle speed and the load correction amount.

[0026] An air / fuel ratio sensor 8 is mounted on an exhaust line 64 of the engine 65 and outputs a signal according to the oxygen concentration of the exhaust gas, which is expelled via the exhaust valve 36 to the exhaust line 64. This sensor signal is input into the ECU 100 and the fuel injection pulse width of the injector 23 is adjusted so that the target air / fuel ratio is maintained according to the operating conditions.

[0027] As in Fig. As shown in Figure 2, the ECU 100 contains a microcomputer comprising a central processing unit (CPU) 101, a power supply IC 102, a read / write memory (RAM) (not shown), a read-only memory (ROM) (not shown), and the like. The CPU 101 of the ECU 100 performs various control operations related to the power unit 65 by executing different control programs stored in the ROM. The signals to be input into the CPU 101 of the ECU 100 are summarized here with reference to the drawing. Signals from the air flow sensor 1, the intake temperature sensor 1a, which is built into the air flow sensor 1, the throttle position sensor 2, the water temperature sensor 3, the crankshaft angle sensor 4, the accelerator pedal depressor 5, the air conditioning switch 6, the idle switch 7, the air / fuel ratio sensor 8, the camshaft angle sensor 9, the knock sensor 34 and the like are input.The output signal of the CPU 101 of the ECU 100 is sent to the fuel pump 20, the injector 23, a power transistor 32 which has a spark plug ignition switch 33, the valve timing adjustment mechanism 37, the throttle actuator 41, and the like. As described above, the signal from the knock sensor 34, which is mounted on the cylinder block 67, is input to the CPU 101. The CPU 101 then performs a knock detection to identify noise other than knocking and actual knocking. During the knock detection, the ignition timing is retarded and a correction is made to suppress the occurrence of knocking.

[0028] The switching-on time of the power transistor 32 is controlled on the basis of the target ignition time for which this correction is performed.

[0029] Fig. Figure 3 is a diagram showing the frequency analysis result of the pressure sensor output (the output of the pressure sensor that detects the pressure in cylinder 66) and the knock sensor output (the output of knock sensor 34 that detects the vibration of cylinder 66 of the cylinder block 67) during the operating cycle in which knocking occurs. The vertical axis (the knock intensity) in the upper drawing of Fig. 3 is the square of the pressure sensor's output (pressure), and the unit is [MPa^2]. The vertical axis (the knock strength) in the lower drawing of Fig. 3 is the square of the output (voltage) of the knock sensor 34 and the unit is [V^2].

[0030] As in Fig. As shown in Figure 3, the specific frequencies (Pf1, Pf2, Pf3) of the pressure wave, which is the root cause of the vibration, and the specific frequencies (Kf1, Kf2, Kf3) of the knock sensor signal, which is detected as the vibration of the cylinder blocks (66, 67), do not always coincide. This is because the result of the impact force introduced into the engine blocks (66, 67) when the pressure wave collides with the wall surface passes through the characteristic curve of the engine blocks (66, 67) and appears as a knock sensor output. Additionally, the relationship between the values ​​of the frequency components also differs. That is, in the knock sensor 34, the signal strengths of the specific frequencies Kf1, Kf3, which are located at the positions that bind Kf2, are lower than the signal strength of the central specific frequency Kf2.

[0031] This result differs from the relationship where the signal strength of Pf2, which is the central frequency in the pressure sensor, is smaller than the signal strength of the specific frequencies Pf1 and Pf3 at positions that clamp frequency Pf2. As described above, when a deviation of a specific frequency occurs, the magnitude ratio of the frequency component of the signal also changes. These changes are caused by the presence of the engine blocks (66, 67) that connect the cylinder pressure and the knock sensor. Therefore, the influence of the engine blocks (66, 67) can be evaluated from the relationship between the cylinder pressure and the knock sensor output, as described above, and using this, the characteristics of the cylinder pressure can be easily reconstructed from the knock sensor signal.

[0032] If the conditions of the engine 65 (the engine operating condition), such as the number of cylinders of the engine 65, the rotational speed of the engine 65, the load of the engine 65, and the coolant temperature detected by the water temperature sensor 3, are essentially the same, knocking occurs at the same specific frequency (Kf1, Kf2, Kf3) of the knock sensor signal. If the aforementioned engine operating conditions are essentially the same, knocking occurs at the specific frequency (Pf1, Pf2, Pf3) of the pressure wave determined by the pressure sensor mounted on the inside of the cylinder 66.

[0033] Fig. Figure 4 shows the linear relationship between the signal value (signal strength) of a specific frequency of the knock sensor signal and the signal value (signal strength) of a specific frequency of the pressure sensor signal. Fig. 4. The intensities P(Pf1), P(Pf2) of the pressure sensor signals of the specific frequencies Pf1, Pf2 are calculated. Fig. 3 and the intensities K(Kf1), K(Kf2) of the knock sensor signals of the specific frequencies Kf1, Kf2 are used to adopt the relationship of equation (1) below and to graphically represent the values ​​of several operating cycles. [Equation 1] P(Pf1)+P(Pf2)=K(Kf1)+2K(Kf2)

[0034] This means that the knock intensity K(Kfi) of the specific frequency of the knock sensor signal is corrected by the knock intensity P(Pfi) of the specific frequency of the pressure sensor signal according to the change in specific frequency due to the engine blocks (66, 67). In the equation (1) described above, K(Kf1) is corrected to P(Pf1) and K(Kf2) is corrected to P(Pf2). Furthermore, taking into account damping, the weight coefficient of the low frequency component (K(Kf1)) of the knock sensor signal is set to 1 and the weight coefficient of the high frequency component (K(Kf2)) is set to 2 to be large. As a result, the knock intensity (the cylinder-internal pressure intensity) of the specific frequency of the pressure sensor signal can be calculated from the knock intensity of the specific frequency of the knock sensor signal.

[0035] Therefore, in the present embodiment, the relationship to the specific frequencies (Pf1, Pf2, and the like) of the pressure wave, which corresponds to the specific frequencies (Kf1, Kf2, and the like) of the knock sensor signal, is stored in RAM or ROM for each power engine operating state. Then, as described above, the weighting coefficients for calculating the knock intensity P(Pfi) of the specific frequency of the pressure sensor signal from the knock intensity K(Kfi) of the specific frequency of the knock sensor signal are stored in RAM or ROM.As a result, the CPU 101 of the ECU 100 uses the relationship between the specific frequencies (Kf1, Kf2, etc.) of the knock sensor signal and the specific frequencies (Pf1, Pf2, etc.) of the pressure wave, as well as the weight coefficients stored in RAM or ROM, to calculate the knock intensity (the cylinder-internal pressure P(Pfi)) at a specific frequency of the pressure sensor signal from the knock sensor signal. The CPU 101 then determines the presence or absence of knocking based on the knock intensity (the cylinder-internal pressure) of the calculated pressure sensor signal at a specific frequency. <Klopfbestimmung und Klopfsteuerung durch die ECU in der vorliegenden Ausführungsform>

[0036] Fig. Figure 5 is an operating plan to explain a procedure for determining the presence or absence of knocking in the present embodiment. It is assumed that each step in Fig. 5 is performed by the CPU 101 of the ECU 100. The processing of each operating block is described below. Fig. 5 described.

[0037] In the present embodiment, which is described in Fig. As shown in Figure 5, the frequency band (cutoff frequency or passband) detected by the knock detection filter is adjusted according to the state of the engine 65 (engine operating state), such as the number of cylinders of the engine 65, the speed of the engine 65, the load, and the coolant temperature detected by the water temperature sensor 3.

[0038] In particular, a filter identification map is stored in the RAM or ROM of the ECU 100, in which several filters, which will be described later and have different cutoff frequencies or passbands, are registered as individual codes. The CPU 101 then selects the corresponding filter identifier from the filter identification map according to the engine operating state described above (S501). The filter identification map will be described later; however, this filter identifier is associated with a filter coefficient that sets the filter characteristics. Therefore, by selecting the filter identifier from the filter identification map, it is possible to set the knock detection filter by determining the frequency band (the cutoff frequency or passband) and the attenuation band corresponding to the filter identifier (S502).

[0039] The knock sensor 34 detects the vibration of the force machine 65 (S301), and the A / D converter transforms the detection result into a digital signal (S302). The knock sensor output of knock sensor 34 is output as a signal in a desired frequency band by the knock detection filter, which is set in S501. Here, a knock detection filter (a bandpass filter) with a cutoff frequency or passband whose resonant frequency (specific frequency) is 7 kHz, 9 kHz, or 12 kHz is set in conjunction with the selected filter identifier, and three frequency components that have passed through the knock detection filter are illustrated. That is, the CPU 101 processes the knock sensor output signal of knock sensor 34 using the knock detection filter, which is set by selecting the filter identifier in S501. The CPU 101 then calculates the knock intensity K(Kfi) of each resonant frequency (Kfi) from the output of the knock detection filter (S303).

[0040] Here, as described above, the CPU 101 uses the relationship between the specific frequencies (Kf1, Kf2 and the like) of the knock sensor signal and the specific frequencies (Pf1, Pf2 and the like) of the pressure wave and the weight coefficients stored in RAM or ROM to calculate the knock strength (the cylinder-internal pressure strength) of a specific frequency of the pressure sensor signal from the knock sensor signal.

[0041] This means that the CPU 101 calculates the specific frequency (Pfi) of the pressure wave, which corresponds to the specific frequency (7 kHz, 9 kHz, 12 kHz) of the knock sensor signal, based on the engine operating conditions, such as engine speed and load. Furthermore, the CPU 101 calculates the weight coefficient, which corresponds to the engine operating conditions, and calculates the knock intensity (P(Pfi)) of the specific frequency of the pressure sensor signal based on the correspondence between the weight coefficient and the aforementioned specific frequency (Pfi) (S303).

[0042] The CPU 101 calculates the weighted average of the background level (BGL1, ..., BGLi) for each specific frequency (7 kHz, 9 kHz, 12 kHz) (S304). Then, the CPU 101 calculates the ratio SLi = Pfi / BGLi of the knock intensity (Pfi) calculated above to the background level BGLi for each specific frequency (7 kHz, 9 kHz, 12 kHz) (S305). The CPU 101 integrates SLi = P (Pfi) / BGLi for each specific frequency (7 kHz, 9 kHz, 12 kHz). In other words, if m specific frequencies are present, by calculating ∑i=1mSLi A knock test value I is calculated (S306). In S305, the procedure for recording each ratio was described; however, this is not limited to the ratio, and the knock test value I can be determined by calculating the difference and integrating the difference.

[0043] The CPU 101 determines a knock detection threshold Ith based on the rotational speed Ne of the engine 65 (S307). Specifically, the CPU 101 refers to characteristic map data (a data table) in which the rotational speed Ne of the engine 65 (the operating state of the engine 65) and the knock detection threshold are predefined, and determines the knock detection threshold Ith from the rotational speed Ne of the engine 65. The CPU 101 determines the presence or absence of knocking by comparing a knock reading I with the knock detection threshold Ith and outputs the knock detection result (S308).

[0044] Fig. Figure 6 is an operating flowchart to explain the knock determination and knock control procedure in the present embodiment, which is based on Fig. 5 were described.

[0045] According to S501 of Fig. 5. The CPU 101 executes the operation of the engine operating state (which can be referred to as the engine operating condition) by detecting signals indicating the state of the engine 65, such as the number of cylinders of the engine 65, the rotational speed of the engine 65, the load, and the coolant temperature detected by the water temperature sensor 3 (S600). Then, according to S502, the CPU 101 selects from Fig. 5. A filter identifier from the filter identifier map is selected based on the engine operating state (S601). A filter identifier map, which will be described later, and a filter coefficient corresponding to each filter identifier are stored in the RAM or ROM of the ECU 100. Therefore, by selecting the filter identifier in S601, the CPU 101 sets the knock detection filter, such as the desired frequency band (the cutoff frequency or the passband), and the attenuation band using the corresponding filter coefficient (S602).

[0046] After that, the CPU 101 executes according to S301 and S302 from Fig. 5 performs an A / D conversion on the knock signal from knock sensor 34 and records the A / D conversion result (S603). Furthermore, according to S303, CPU 101 performs Fig. 5. Filtering processing of the A / D-converted knock signal using the knock detection filter set in S602 is performed by (S604). Furthermore, the CPU 101 calculates the knock intensity at a specific frequency of the knock sensor signal based on the filtered knock signal (S605). In the present embodiment, the relationship to the specific frequencies (Pf1, Pf2, and the like) of the pressure wave, which correspond to the specific frequencies (Kf1, Kf2, and the like) of the knock sensor signal, is stored in RAM or ROM for each power machine operating state.As a result, the CPU 101 uses the relationship between the specific frequencies (Kf1, Kf2, and the like) of the knock sensor signal and the specific frequencies (Pf1, Pf2, and the like) of the pressure wave, and the weight coefficients stored in RAM or ROM, to calculate the knock intensity (the cylinder-internal pressure P(Pfi)) of a specific frequency of the pressure sensor signal from the knock sensor signal (S606). Although in the present embodiment, as described above, the relationship between the specific frequencies (Kf1, Kf2, and the like) of the knock sensor signal and the specific frequencies (Pf1, Pf2, and the like) of the pressure wave, and the weight coefficient stored in RAM or ROM, are used to calculate the knock intensity (the cylinder-internal pressure) of a specific frequency of the pressure sensor signal, the present invention is not limited thereto.This means that even without this implementation, it is possible to perform a subsequent knock determination using the knock intensity (K(Kfi)) of a specific frequency (Kf1, Kf2 and the like) of the knock sensor signal.

[0047] Referring to S305 from Fig. In section 5, the CPU 101 also calculates the ratio SLi = P(Pfi) / BGLi of the weighted average of the background level (BGLi) to the knock intensity (P(Pfi)) for each specific frequency (Pfi) (S607). With reference to S306 of Fig. 5. The CPU 101 also calculates when the number of specific frequencies is m. ∑i=1mSLi, to calculate the knock determination value I (S608).

[0048] Then, if the knock measurement value I is greater than the knock measurement threshold Ith (S609), it is determined that knocking has occurred (S610) and a knock indicator is set to "1" (S611). Conversely, if the knock measurement value I is equal to or less than the knock measurement threshold Ith (S609), the knock indicator is set to "0" (S612). When the knock indicator becomes 1, the CPU 101 performs a control action by retarding the ignition timing of spark plug 33 so that no knocking occurs. <Filtereinstellung / -auswahl durch die ECU in der vorliegenden Ausführungsform>

[0049] Fig. Figure 7 shows an example of a filter setting control example by the CPU 101 of the ECU 100 in the present embodiment.

[0050] As in Fig. 5 and Fig. As described in section 6, a filter identification map is stored in the RAM or ROM of the ECU 100. Fig. The CPU 101 stores several filters, which will be described later and have different cutoff frequencies or passbands, as individual codes (ID1, ID2, ID3, ID4, ID5, ID6). The CPU 101 then selects the corresponding filter identifier from the filter identifier map according to the engine operating state (the number of cylinders in engine 65, the engine speed 65, the load, the cooling water temperature detected by water temperature sensor 3, and the like). The filter identifier is assigned a filter coefficient, which sets the filter characteristics. Therefore, by selecting the filter identifier from the filter identifier map, it is possible to set the knock detection filter by determining the frequency band (the cutoff frequency or passband) and the attenuation band corresponding to the filter identifier.

[0051] Fig. Figure 7 shows an example of a three-stage secondary IIR filter as a filter identifier 1. For the first-stage secondary IIR filter of Fig. 7. Filter coefficients such as a11, a12, w1(n-1), w1(n-2), b00, b10, b11, and b12 are set. Correspondingly, filter coefficients are set for the second- and third-stage IIR filters. These filter coefficients determine the filter characteristics, such as the frequency band (cutoff frequency or passband) of the signal that is allowed to pass through, or the attenuation bands. The CPU 101 then processes the detection signal from the knock sensor 34 using the knock detection filter, whose filter characteristics are determined by the filter type (IIR filter, FIR filter, etc.) and the filter coefficients assigned to the selected filter identifier.

[0052] This means that the required filter characteristics vary depending on the engine operating conditions, such as the number of cylinders of engine 65, the rotational speed of engine 65, the load, the cooling water temperature detected by the water temperature sensor 3, and the like. Therefore, in the present embodiment, the filter identifier is pre-assigned to the filter type and the filter coefficient, and the CPU 101 can select a preset filter identifier according to the engine operating conditions. As a result, the filter type and the filter coefficient are set such that the desired filter characteristics associated with the filter identifier are obtained, thereby enabling knock detection using the knock detection filter.

[0053] The above description explained the point of assigning the filter characteristics to the filter identifier. However, since the desired relationship between the aforementioned specific frequency of the knock sensor signal (Kf1, Kf2, etc.) and the specific frequency of the pressure wave (Pf1, Pf2, etc.) and a weighting coefficient are determined depending on the engine operating state, their setting in conjunction with the filter identifier is possible. That is, when the CPU 101 selects the filter identifier based on the engine operating state, the relationship between the specific frequency of the knock sensor signal (Kf1, Kf2, etc.) and the specific frequency of the pressure wave (Pf1, Pf2, etc.) or a weighting coefficient corresponding to the filter identifier is set.As a result, the CPU 101 can accurately detect knocking based on the desired relationship between the specific frequency of the knock sensor signal (Kf1, Kf2 and the like) and the specific frequency of the pressure wave (Pf1, Pf2 and the like) or the weight coefficient.

[0054] In the ECU 100 of the present embodiment, the filter type and filter coefficient are pre-stored in RAM or ROM for each filter such that multiple filters with different desired frequency bands (cutoff frequencies or passbands) are obtained. It is desirable that the desired frequency band (cutoff frequency or passband), i.e., the filter characteristics, be set in such a way that knock detection in a general power machine can be performed accurately. Therefore, the ECU 100 of the present embodiment includes a function for pre-storing, with respect to this filter characteristic (cutoff frequency or passband), only the filter type and filter coefficient required to fulfill the filter characteristic (cutoff frequency or passband) in RAM or ROM, and for assigning the filter identifier to the filter characteristic (cutoff frequency or passband).As a result, the person performing the ECU 100 calibration process can complete the calibration by simply setting which filter identifier (i.e., which filter characteristic) should be assigned to which power machine operating state. Therefore, since it is not necessary to set the filter type and filter coefficient, which are complex, it is possible to create an ECU that can perform the calibration process easily.

[0055] As in Fig. As shown in Figure 8, the filter identification map is subdivided into several filter identification maps for each filter channel. Therefore, for CPU 101, the filter identification map is first selected based on the power machine operating state, and then the corresponding filter identifier is chosen from the selected filter identification map. Fig. In section 8, it is assumed that m filter identifier fields exist, and filter identifiers are shown as filter identifier 1 to filter identifier m. When the filter identifier is selected, the corresponding filter type and filter coefficient are set, and this completes the filter setting process of determining which filter from filter 1 to m should be used.

[0056] Fig. Figure 9 shows an example of a filter that can be selected by the CPU 101 of the ECU 100 in the present embodiment and shows an example of a filter of the filter type that is defined by the filter identification map of Fig. 7 and Fig. 8 can be selected. Here is an example of filter characteristics for each number of IIR filter stages. As shown from Fig. As is clearly shown in Figure 9, the filter's characteristics become steeper as the number of filter stages increases. By appropriately adjusting the filter coefficient, it is possible to change the cutoff frequency (Fc1, Fc2), i.e., the passband.

[0057] Fig. Figure 10 shows another example of a filter that can be selected by the CPU 101 of the ECU 100 in the present embodiment, and shows an example of a filter of the filter type that is defined by the filter identification map of Fig. 7 and Fig. 8 can be selected. Here is an example of filter characteristics for each number of FIR filter tap stages. As shown from Fig. As can be clearly seen in section 10, the filter's passband becomes narrower the greater the number of filter stages.

[0058] Fig. Figure 11 is a diagram showing a specific frequency and signal strength of the knock sensor signal for each cylinder in which knocking occurs, and is a diagram to explain the necessity of the filter switching function for each cylinder described above.

[0059] As in Fig. As shown in Figure 11, for example, frequency K2 is a specific frequency found only in the second cylinder, and frequency K7 is a specific frequency found only in the first cylinder. The characteristics of the knock sensor from the cylinder in which knocking occurs differ from cylinder to cylinder. This difference arises because the characteristics depend on the distance, path, shape of the path, and other factors along which the vibration transmitted to the engine blocks (66, 67) by the pressure wave travels. For example, it is necessary to perform a signal correction taking into account the characteristics of the engine blocks (66, 67) by changing the specific frequency chosen for each cylinder.

[0060] In the present embodiment, as described above, the filter characteristics can be set taking into account the properties of the engine blocks (66, 67) corresponding to each cylinder. That is, in the present embodiment, the number of cylinders of the engine 65 is entered into the CPU 101 as one of the engine operating states, and the filter identifier is set such that the desired filter characteristics are obtained based on the number of cylinders. As a result, the CPU 101 selects a filter identifier based on the number of cylinders during operation and sets a knock detection filter that has a filter characteristic desired for the number of cylinders assigned to the filter identifier. Therefore, the conversion of pressure to vibration can be processed appropriately, and the pressure wave intensity can be predicted more accurately.

[0061] Fig. Figure 12 shows an example of the relationship between the state of the power machine 65, the number of cylinders and the knock frequency and the concept of filter setting by the CPU 101 of the ECU 100 in the present embodiment and is a graph in which the frequency analysis result of one cylinder and two cylinders at 1200 min -1 and one cylinder and two cylinders at 2400 min -1 .

[0062] As can be seen from the graph in Fig. As becomes clear in point 12, it is evident that two cylinders are running at 1200 rpm. -1 and one cylinder at 2400 min -1 They exhibit peak values ​​at almost the same frequency. In a filter adjustment procedure in such a case, the filter requirements of the two cylinders are at 1200 rpm. -1 and of one cylinder at 2400 min -1They are identical and can be integrated in such a way that a filter with the same filter identifier can be used. Therefore, it is possible to easily set a complex filter coefficient.

[0063] Fig. Figure 13 is an example of a relationship between a state of the power machine 65, a number of cylinders and a knock occurrence frequency and a filter setting by the CPU 101 of the ECU 100 in the present embodiment.

[0064] As can be seen from the table in Fig. As can be seen in section 13, since there are several identical frequencies in the table, it is easy to set the filter by setting the same filter identifier for this part.

[0065] Fig. Figure 14 is a diagram to explain the necessity of the filter switching function for the relationship between the state of the power machine 65 and the knock occurrence frequency by the CPU 101 of the ECU 100 in the present embodiment and is a diagram showing a specific frequency and signal strength of a knock sensor signal for each coolant temperature when knocking occurs.

[0066] As in Fig. As shown in Figure 14, frequencies K2, K4, and K8 are specific frequencies found only at low water temperatures, while frequencies K3 and K5 are specific frequencies found only at high water temperatures. The cooling water temperature at the time knocking occurs changes the specific frequency of the pressure wave due to the change in the cylinder's internal temperature and also alters the engine block's properties. This change in the engine block's properties is attributed to the change in the speed of sound in water due to the temperature change. As a result, the specific frequency, which appears as the knock sensor signal 34, also changes.For example, it is necessary to perform signal correction taking into account the properties of the engine block, which change depending on the cooling water temperature, by changing the specific frequency selected for each cooling water temperature. In the present embodiment, as described above, the filter characteristics are set taking into account the properties of the engine block corresponding to each cooling water temperature.

[0067] In the present embodiment, the cooling water temperature is input into the CPU 101 as one of the power machine operating states, and the filter identifier is set based on the cooling water temperature to obtain the desired filter characteristics. As a result, the CPU 101 selects a filter identifier based on the cooling water temperature, and a knock detection filter with a filter characteristic corresponding to the desired cooling water temperature is selected. Consequently, the conversion of pressure to vibration can be processed effectively, and the pressure wave intensity can be predicted more accurately.

[0068] Fig. 15 is an example of a relationship between a state of the power machine 65, a number of cylinders and a knock occurrence frequency and a filter setting by the CPU 101 of the ECU 100 in the present embodiment.

[0069] As shown in the table in Fig. As is clearly shown in section 15, since there are several identical frequencies in the table, it is easy to set the filter by applying the same filter identifier to this part.

[0070] Fig. Figure 16 shows a functional block diagram of the CPU 101, in which the knock sensor signal is detected, the knock sensor signal is corrected for each cylinder, and the knock strength operation is performed.

[0071] As described above, the signal detected by the knock sensor 34 is corrected taking into account the influence of the engine block (knock sensor signal correction). However, here the number of cylinders in the engine 65 or the coolant temperature in each cylinder is used as the input signal for the CPU 101, and the corresponding filter identifier is selected. The knock sensor signal is then processed by the knock detection filter with the filter characteristic assigned to the filter identifier, and the knock intensity (pressure wave intensity) is calculated based on the processing result.

[0072] As described above, the signal processing unit (ECU 100) of the present embodiment filters the output signal of the sensor (knock sensor 34) mounted on the vehicle. Furthermore, the signal processing unit (ECU 100) of the present embodiment incorporates a setting for multiple filters, which have different filter types (IIR filters, FIR filters, and the like) or filter coefficients (a11, a12, w1(n-1), w1(n-2), b00, b10, b11, b12, and the like). Fig.7) is carried out to set the cutoff frequency, or the filter characteristic of the passband It is set for several filters with different n-1), and an individual code (a filter identifier) ​​is set for each of the several filters. Then, in the signal processing device (ECU 100) of the present embodiment, the CPU 101 selects an individual code (a filter identifier) ​​based on the engine operating state in order to select a corresponding filter and processes an output signal from a sensor (the knock sensor 34) using the selected filter. It is desirable that the sensor is the knock sensor 34, which detects knocking of the engine 65 mounted on the vehicle.

[0073] It is desirable that the CPU 101 calculates the knock intensity (K(Kfi)) of a specific frequency of the knock sensor signal based on the signal processed by the selected filter.Furthermore, it is desirable that the signal processing device (ECU 100) includes a memory unit (a RAM or a ROM, not shown) that stores the relationship to the specific frequency (Pfi) of the pressure wave in the cylinder, corresponding to the specific frequency (Kfi) of the knock sensor signal, for each power machine operating state, and that the CPU 101 calculates the knock strength (K(Kfi)) of a specific frequency of the knock sensor signal based on the signal processed by the selected filter, and uses the relationship between the specific frequency (Kfi) of the knock sensor signal and the specific frequency (Pfi) of the pressure wave stored in the memory unit and the weight coefficient to calculate the knock strength (P(Pfi)) of a specific frequency of a pressure sensor signal for detecting the pressure wave in the cylinder from the knock sensor signal.

[0074] Furthermore, as described above, it is desirable that when an individual code (a filter identifier) ​​is set for the relationship between the specific frequency (Kfi) of the knock sensor signal and the specific frequency (Pfi) of the pressure wave and the weight coefficients, and the CPU 101 selects an individual code (a filter identifier) ​​based on the power machine operating state, the relationship between the specific frequency (Kfi) of the knock sensor signal and the specific frequency (Pfi) of the pressure wave, or the weight coefficient corresponding to the individual code, is set.

[0075] It is desirable that when the CPU 101 calculates the ratio SLi = P (Pfi) / BGLi of the weighted average of the background level (BGLi) to the knock intensity (P(Pfi)) for each specific frequency (Pfi) and m specific frequencies are present, the CPU 101 ∑i=1mSLi The system calculates the knock detection value I and determines that knocking has occurred if the knock detection value I is greater than the knock detection threshold Ith. It is desirable that the engine operating condition be the number of cylinders of engine 65 and / or the rotational speed of engine 65 and / or the load of engine 65 and / or the cooling water temperature detected by water temperature sensor 3.

[0076] As described above, in the present embodiment the power machine control device (ECU 100), which controls the power machine 65 containing a sensor (a knock sensor 34), includes a memory unit (a RAM or a ROM, not shown) that stores a filter type and a filter coefficient for setting multiple filters having different cutoff frequencies or passbands, and has an individual code assignment function that can assign an individual code (a filter identifier) ​​to each of the multiple filters. A corresponding filter is selected by choosing the individual code (the filter identifier) ​​based on the power machine operating state, and the power machine control device (ECU 100) includes a CPU 101 that processes the output signal of the sensor (knock sensor 34) using the selected filter.

[0077] According to the embodiment described above, it is possible to create an easy-to-use filter that can reduce the workload of a parameter setting operator in response to an increase in the parameters that constitute a complicated filter control.

[0078] Each component, function, processing unit, processing means and the like described above can be implemented by hardware, e.g. by designing part or all of them in an integrated circuit or the like.

[0079] Each component, function, and the like described above can be implemented by software through the interpretation and execution of a program by which the processor carries out each function. Data such as programs, tables, files, and the like, implementing each function, can be stored in a storage device such as a data storage device, a hard disk drive, or a stable-state drive (SSD), or in a storage medium such as an IC card, an SD card, or a DVD.

[0080] Furthermore, control lines and data lines indicate what is deemed necessary for explanation, and not all control lines and data lines are necessarily shown in the product. In practice, it can be assumed that almost all structures are interconnected. Reference symbol list 1 air flow sensor 1a Intake air temperature sensor 2 Throttle position sensor 3 Water temperature sensor 4 Crank angle sensor 5 Accelerator pedal depression sensor 6 air conditioning switches 7 Idle switches 8 Air / Fuel Ratio Sensor 9 Camshaft angle sensor 20 Fuel pump 21 Fuel tank 22 pressure regulators 23 Injector 32 Power transistor 33 Spark plug 34 Knock sensor 35 Inlet valve 36 Exhaust valve 37 Valve timing adjustment mechanism 40 Throttle valve 41 Throttle valve control motor 60 air purifiers Channel 61 62 Collector 63 Admission Management 64 Outlet pipe 65 Power machine 66 cylinders 67 cylinder block 68 cooling fans 100 Control ECU (signal processing device, power machine control device) 101 CPU

Claims

[1] Signal processing device (100) which filters an output signal of a sensor mounted on a vehicle, comprising: a storage unit configured to store a relationship to a specific frequency (Pfi) of a pressure wave in a cylinder (66) corresponding to a specific frequency (Kfi) of a knock sensor signal, for each power machine operating state; and a central processing unit, CPU, (101) which is configured: to make a setting with respect to multiple filters that have different filter types or filter coefficients for setting a filter characteristic of a cutoff frequency or a passband; to set an individual code for each of the multiple filters, and to select the individual code based on a power machine operating state in such a way that a corresponding filter is selected, and to process an output signal from the sensor using the selected filter, wherein: the sensor is a knock sensor (34) that detects knocking from a power unit (65) mounted on the vehicle; and The CPU (101) is configured to calculate a knock strength (K(Kfi)) of a specific frequency of a knock sensor signal based on a signal processed by the filter that has been selected. [2] Signal processing device according to claim 1, wherein the CPU (101) is configured to use the relationship stored in the memory unit between the specific frequency (Kfi) of the knock sensor signal and the specific frequency (Pfi) of the pressure wave and a weight coefficient to calculate a knock intensity (P(PFi)) of a specific frequency (Kfi) of the knock sensor signal in order to detect the pressure wave in the cylinder from the knock sensor signal. [3] Signal processing device according to claim 2, wherein (i) a filter identifier is set for the relationship between the specific frequency (Kfi) of the knock sensor signal and the specific frequency (Pfi) of the pressure wave and the weight coefficients, and (ii) the CPU (101) sets the filter identifier based on the power machine operating state, the relationship between the specific frequency (Kfi) of the knock sensor signal and the specific frequency (Pfi) of the pressure wave or the weight coefficient, which is set according to the filter identifier. [4] Signal processing device (100) according to claim 2, wherein the CPU (101) is configured, then, when the CPU (101) calculates a ratio SLi = P (Pfi) / BGLi of the weighted average of the background level (BGLi) to the knock intensity (P(Pfi)) for each specific frequency (Pfi) and m specific frequencies are present, the CPU (101) ∑i=1mSLi calculated to determine a knock measurement value I, and to determine that knocking has occurred if the knock measurement value I is greater than a knock measurement threshold value Ith. [5] Signal processing device (100) according to claim 1, wherein the power machine operating state is a number of cylinders of the power machine (65) and / or a rotational speed of the power machine (65) and / or a load of the power machine (65) and / or a cooling water temperature detected by a water temperature sensor (3). [6] Power machine control device (100) controlling a power machine (65) containing a sensor, comprising: a memory unit storing a filter type and a filter coefficient for setting multiple filters having different cutoff frequencies or passbands; and a central processing unit, CPU, (101) with individual code assignment function that can assign an individual code to each of the multiple filters, wherein one CPU (101) is configured to select the individual code based on a power machine operating state such that an appropriate filter is selected, and to process an output signal of the sensor using the filter that was selected, wherein the sensor is a knock sensor (34) that detects knocking of a power unit (65) mounted on the vehicle, and wherein the storage unit stores a relationship to a specific frequency (Pfi) of a pressure wave in a cylinder (66) corresponding to a specific frequency (Kfi) of a knock sensor signal for each power machine operating state.

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