阅读说明：本技术 失火发生判定装置、失火发生判定系统、失火发生判定方法以及程序 (Misfire occurrence determination device, misfire occurrence determination system, misfire occurrence determination method, and program ) 是由 八岛寛 川越纯 于 2018-06-05 设计创作，主要内容包括：本发明能够以简单的构成利用点火噪声判定失火发生。控制装置100能够判定通过点火线圈185的次级侧电流而发出火花的火花塞45的失火发生。本发明包括：点火控制部160,输出用于控制点火运行的点火控制信号；点燃部170,根据点火控制信号,对点火线圈185的初级侧电流进行导通、切断控制；接收部190,接收通过点燃部的控制运行而从火花塞45放射的点火噪声；以及失火发生判定部180,基于所放射的点火噪声,判定失火发生。(The invention can judge the fire occurrence by the ignition noise with a simple structure. The control device 100 can determine the occurrence of misfire in the ignition plug 45 that generates a spark by the secondary side current of the ignition coil 185. The invention comprises the following steps: an ignition control unit 160 that outputs an ignition control signal for controlling an ignition operation; an ignition section 170 for controlling the on/off of the primary side current of the ignition coil 185 based on the ignition control signal; a receiving unit 190 that receives the ignition noise emitted from the ignition plug 45 by the control operation of the ignition unit; and a misfire occurrence determination unit 180 that determines the occurrence of misfire based on the radiated ignition noise.)

1. A misfire occurrence determination device capable of determining the occurrence of a misfire in a spark plug that generates a spark by a secondary side current of an ignition coil, comprising:

an ignition control section that outputs an ignition control signal for controlling an ignition operation;

an ignition unit that controls on/off of a primary side current of the ignition coil based on the ignition control signal;

a receiving portion that receives ignition noise radiated from the ignition plug by a control operation of the ignition portion; and

and a misfire occurrence determination unit that determines the occurrence of misfire based on the radiated ignition noise.

2. The control device according to claim 1, characterized in that:

the ignition noise is a harmonic component of the ignition noise caused by spark discharge.

3. The misfire occurrence determination device according to claim 1 or 2, characterized by further comprising:

and a specific frequency component extraction unit that extracts a specific frequency component of the received ignition noise.

4. The misfire occurrence determination apparatus according to claim 3, characterized in that:

the specific frequency component extracting section includes a band-pass filter.

5. The misfire occurrence determination device according to claim 3 or 4, characterized in that:

the specific frequency component extracting unit may further include an amplifying unit that amplifies the extracted specific frequency component signal, or an attenuating unit that attenuates the extracted specific frequency component signal.

6. The misfire occurrence determination device according to any one of claims 1, 2, 3, 4 and 5, characterized in that:

the misfire occurrence determination section determines whether ignition by the ignition plug is normal ignition or misfire occurrence, based on whether or not the amplitude of the ignition noise exceeds a predetermined value.

7. The misfire occurrence determination device according to any one of claims 1, 2, 3, 4, 5 and 6, characterized in that:

the receiving unit is an antenna provided on a printed circuit board, and the printed circuit board is provided with a control device for controlling the engine.

8. The misfire occurrence determination apparatus according to claim 7, characterized in that:

the antenna is any one of a conductor pattern formed of a conductive material on an insulating substrate of the printed circuit board, an inductance element, and a resistance having an inductance component.

9. A misfire occurrence determination system that is a system capable of determining occurrence of misfire includes:

an ignition coil including a primary coil and a secondary coil;

a spark plug that emits a spark by a secondary side current flowing through the secondary coil;

an ignition unit that controls the on/off of a primary side current flowing through the primary coil in accordance with an applied ignition control signal;

an ignition control unit that outputs the ignition control signal to the ignition unit;

a receiving portion that receives ignition noise radiated from the ignition plug by a control operation of the ignition portion; and

and a misfire occurrence determination unit that determines the occurrence of misfire based on the radiated ignition noise.

10. A misfire occurrence determination method capable of determining the occurrence of a misfire in a spark plug that emits a spark by a secondary side current of an ignition coil, comprising:

a step of outputting an ignition control signal for controlling an ignition operation;

controlling the on/off of the primary side current of the ignition coil according to the ignition control signal;

a step of receiving ignition noise radiated from the spark plug; and

and determining the occurrence of misfire based on the radiated ignition noise.

11. A program for determining the presence or absence of misfire in a spark plug that generates a spark by a secondary-side current of an ignition coil, the program causing a computer to execute:

a process of outputting an ignition control signal for controlling an ignition operation;

processing for performing energization or cutoff control of a primary side current of the ignition coil; and

and a process of judging the occurrence of misfire based on the ignition noise radiated from the ignition plug.

Technical Field

The present invention relates to a misfire occurrence determination apparatus, a misfire occurrence determination system, a misfire occurrence determination method, and a program that can determine the occurrence of a misfire with a simple configuration.

Background

Various devices capable of detecting misfire have been proposed from the past. For example, a device has been proposed which monitors the amount of change in angular velocity of a crankshaft to estimate the detected misfire. First, when the "inter-cycle variation difference" that is the difference between the crank shaft angular velocity variations in a cycle and the cycle immediately before the cycle exceeds a predetermined threshold, the apparatus calculates the cycle as a "variation large cycle". Then, when the number of "large variation cycles" reaches a predetermined misfire detection count within the monitoring cycles of the preset number of cycles, it is estimated that the engine misfire is detected (see patent document 1).

Further, another device capable of misfire detection includes: an ion current detection circuit for detecting an ionization current flowing when an atmosphere between electrodes of the spark plug is ionized; and a waveform processing circuit that performs signal processing on the ionization current. Further, the waveform processing circuit includes: a first function of inverting an output of the ion current detection circuit and comparing the inverted output with a first reference voltage; and a second function of comparing a discharge waveform of a time constant circuit that performs charging and discharging by the comparison output with a second reference voltage to generate a constant time for masking (see patent document 2).

Disclosure of Invention

Problems to be solved by the invention

However, in order to estimate the detected misfire, the device of patent document 1 needs to calculate various parameters such as the difference in the amount of fluctuation between cycles, and needs to prepare various flags or work areas such as a ring buffer. Therefore, the amount of calculation is large, and the amount of memory used is also large. Further, in the apparatus, it is necessary to provide a plurality of reluctance rotors in a pickup for detecting rotation of the crank shaft, and accordingly, an increase in manufacturing cost is caused.

In addition, the device of patent document 2 needs to include an ionization current detection device as a special device in order to detect the misfire. In order to input the output of the ionization current detection device to the engine control unit, it is necessary to draw wiring, etc., which causes a problem of an increase in manufacturing cost, etc.

The present invention has been made to solve the conventional problems, and an object thereof is to provide a misfire occurrence determination device, a misfire occurrence determination system, a misfire occurrence determination method, and a program that can determine the occurrence of a misfire with a low-cost configuration.

Means for solving the problems

The control device according to the present invention for achieving the above object is a device capable of determining the occurrence of misfire in an ignition plug that generates spark by a secondary side current of an ignition coil, and is configured to include: an ignition control section that outputs an ignition control signal for controlling an ignition operation; an ignition part for controlling the conduction and cut-off of the primary side current of the ignition coil according to the ignition control signal; a receiving part receiving the ignition noise radiated from the ignition plug by the control operation of the ignition part; and a misfire occurrence determination unit that determines the occurrence of misfire based on the presence or absence of the radiated ignition noise.

In particular, a harmonic component of the ignition noise may be utilized as the ignition noise.

Further, the ignition noise processing apparatus may further include a specific frequency component extracting unit configured to extract a specific frequency component of the received ignition noise. Further, the specific frequency component extracting section preferably includes a band pass filter.

The specific frequency component extracting unit may further include an amplifying unit that amplifies the extracted specific frequency component signal, or an attenuating unit that attenuates the extracted specific frequency component signal.

The misfire occurrence determination unit may determine whether ignition by the ignition plug is normal ignition or misfire occurrence based on whether or not the amplitude of the ignition noise exceeds a predetermined value. As an example, the specific frequency may be a predetermined frequency band (e.g., ± 0.5(kHz)) in the vicinity of a center frequency of 4 (kHz).

The receiving unit may be an antenna provided on a printed circuit board on which a control device for controlling the engine is provided. The receiving unit can be realized by any of a conductor pattern formed of a conductive material on an insulating substrate of a Printed Circuit Board (PCB), an inductance element, and a resistance element having an inductance component, for example.

Another aspect of the present invention is a system capable of determining occurrence of misfire, including: an ignition coil including a primary coil and a secondary coil; a spark plug for generating a spark by a secondary side current flowing through the secondary coil; an ignition control section that outputs an ignition control signal for controlling an ignition operation; an ignition unit for controlling the on/off of the primary side current flowing through the primary coil in accordance with an applied ignition control signal; an ignition control unit that outputs the ignition control signal to an ignition unit; a receiving part receiving the ignition noise radiated from the ignition plug by the control operation of the ignition part; and a misfire occurrence determination section that determines the occurrence of misfire based on the radiated ignition noise.

Further, an ignition occurrence determination method according to the present invention is a method for determining an occurrence of misfire in an ignition plug that generates a spark by a secondary side current of an ignition coil, including: a step of outputting an ignition control signal for controlling an ignition operation; controlling the conduction and the cut-off of the primary side current of the ignition coil according to the ignition control signal; a step of receiving ignition noise radiated from the spark plug; and a step of judging the occurrence of misfire based on the radiated ignition noise.

Further, the misfire occurrence determination program of the present invention is a program for determining whether or not the misfire occurrence of the ignition plug that generates the spark by the secondary side current of the ignition coil is present, and causes a computer to execute: a process of outputting an ignition control signal for controlling an ignition operation; processing for controlling the energization and the interruption of the primary side current of the ignition coil; and a process of judging the occurrence of misfire based on the ignition noise emitted from the ignition plug.

Further, the present invention may provide a non-transitory recording medium in which the program is recorded. Examples of a non-transitory recording medium on which a program is recorded include: semiconductor devices such as Read Only Memories (ROMs), optical devices such as Compact Discs (CDs) and Digital Video Discs (DVDs), magnetic devices such as magnetic disks, and the like. The recording medium is not limited in its kind as long as it can be executed on a computer by storing a program and reading the stored program with a reading means.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to obtain an effect that the presence or absence of misfire can be determined with an inexpensive configuration.

Drawings

Fig. 1 is a schematic explanatory diagram of an outline of the configuration of the engine 1.

Fig. 2 is a functional configuration diagram of the control device 100.

Fig. 3 is a functional block diagram of the misfire occurrence determination section 180.

Fig. 4 is a hardware configuration diagram of the control device 100.

Fig. 5 shows an example of the frequency characteristic of a Band Pass Filter (BPF).

Fig. 6 is a schematic explanatory view of the antenna.

Fig. 7 is a flowchart for operational explanation.

Fig. 8 is a waveform example for explaining an operation example.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments of the present invention described below are examples, and the present invention is not limited to the embodiments described below, and various modifications, changes, and the like can be made to the configuration examples and the like of the present embodiment. In the embodiment shown below, in particular, the engine 1 having a stroke of four cycles in a single cylinder is assumed, but the number of cylinders or the arrangement pattern of the cylinders of the invention may be suitably applied to the engine.

(outline of Engine 1)

Fig. 1 is a schematic configuration diagram of a control system including an engine 1 and a control device 100. The engine 1 includes a cylinder 2 and a piston 3, and the piston 3 is fitted in the cylinder 2 so as to be slidable in the vertical direction. One end side of a connecting rod (connecting rod)4 is connected to the piston 3, and the other end side of the connecting rod 4 is connected to a crankshaft (crank draft) 5. A flywheel (flywheel)7 is rotatably fixed to an end portion of the crankshaft 5 on the transmission (not shown) side. A reluctance rotor (reluctor)20, which is a protrusion including a magnetic body, is formed in a predetermined angular region of the outer periphery of the flywheel 7.

The electromagnetic pickup 22 disposed opposite the crank shaft 5 outputs a pulse of a positive voltage when the reluctance rotor 20 approaches, and outputs a pulse of a negative voltage when the reluctance rotor 20 moves away. When the pulse is shaped based on the positive and negative polarity pulse signals by a well-known pulse shaping circuit to output one rectangular pulse, the flywheel 7 outputs one rectangular pulse per one rotation. Therefore, in one cycle of "intake → compression → combustion → exhaust", the crankshaft 5 rotates 720 °, and thus two pulses of rectangular signals (engine rotation signals) are output from the electromagnetic pickup 22 in one cycle.

The rotation speed of the engine 1 can be found based on the engine rotation signal from the electromagnetic pickup 22. Further, the formation position of the reluctance rotor 20 on the outer periphery of the flywheel 7 may be set to an appropriate angular region, and the timing of applying an ignition control signal to the ignition plug 45 based on the engine rotation signal from the electromagnetic pickup 22 to ignite the fuel may be set to a desired timing. The desired timing is a timing corresponding to a Top Dead Center (TDC), a more advanced than Top Dead Center (BTDC) side, or a retarded Angle (ATDC) side.

An intake pipe 50 and an exhaust pipe 60 are connected to a cylinder head (cylinder head) above the cylinder 2. The inside of the intake pipe 50 becomes an intake passage 51 for introducing fresh air from the outside into the combustion chamber 70. Further, an air cleaner (air cleaner)32 for removing dust and the like of fresh air, a throttle valve 24 for adjusting an intake amount of fresh air, an injector (injector) 40 for performing fuel injection, and the like are arranged in the intake passage 51 from the upstream side. The timing of introducing the fresh air into the combustion chamber 70 is controlled by the opening and closing operations of the intake valve 12 biased in the valve closing direction by a spring, not shown.

The ignition plug 45 is disposed on the top of the cylinder head in a posture in which the front end face thereof faces the inside of the combustion chamber. Further, a throttle opening sensor 26 that detects the opening of the throttle valve is provided. Although not shown, the fuel stored in the fuel tank is supplied to the injector 40 through a supply hose, while the excess fuel is recovered to the fuel tank through a recovery hose, and the fuel pressurized to a predetermined pressure is always supplied to the injector 40.

On the other hand, the inside of the exhaust pipe 60 forms an exhaust passage 61 for discharging the exhaust gas from the combustion chamber 70. A catalyst device 30 for purifying exhaust gas is disposed downstream of the exhaust passage 61, and O for detecting the concentration of oxygen remaining in the exhaust gas is provided upstream of the catalyst device 30₂ A sensor 28. After the exhaust gas is purified by the catalyst device 30, the exhaust gas may be silenced by a silencer. The timing of discharge of the exhaust gas from the combustion chamber 70 is controlled by the valve opening and closing operation of the exhaust valve 10 biased in the valve closing direction by a spring, not shown.

To a control device 100 for controlling the operation of the engine 1, input signals are received from a throttle opening sensor 26, an electromagnetic pickup 22, and O₂Signals from sensors 28, etc. The indication is input from the throttle opening sensor 26A throttle opening signal of the opening of the throttle valve, and a rectangular pulse signal corresponding to the engine rotation is inputted from the electromagnetic pickup 22. Further, from O₂The sensor 28 receives an input of O indicating the concentration of oxygen remaining in the exhaust gas₂The sensor outputs a signal. On the other hand, a fuel injection control signal for drive-controlling the injector 40 and an ignition control signal for ignition-controlling the ignition plug 45 are input from the control device 100.

Control device 100 based on throttle opening degree signal, engine rotation signal, and O₂The sensor outputs a signal or the like to perform fuel injection control (injection amount, injection timing) by the injector 40, ignition timing control by the ignition plug 45, and the like. The control device 100 of the present embodiment is configured to be able to determine normal ignition and occurrence of misfire.

A spark gap (not shown) is formed in the end portion of the ignition plug 45 on the combustion chamber side, and an air discharge is performed between the spark gaps by a secondary side current of an ignition coil 185 described later, thereby generating an electric spark. That is, the ignition plug 45 sparks out by the secondary side current of the ignition coil 185.

Since spark discharge is performed at a high voltage, a large ignition noise caused by spark discharge is emitted from the spark plug 45 to the space in a normal ignition state. On the other hand, when a misfire occurs, the spark discharge is not normally performed, and therefore, the ignition noise is not radiated into the space. Even in the spark plugs 45 of various types such as the grooved electrode type, the quadrupole type, and the edge type, which are used for ignition and ignition, there is a possibility of misfire occurring, and it is estimated that even in these types, the ignition noise radiated into the space is not radiated at the time of misfire occurrence. In addition, the ignition noise has harmonics with frequencies higher than its fundamental frequency. The harmonics include the nth harmonic (n is an integer of 2 or more).

The reciprocating motion of the piston 3 in the vertical direction in the cylinder 2 is converted into the rotational motion of the crankshaft 5. The rotational motion of the crankshaft 5 is transmitted to the drive wheels via a transmission (not shown), and the vehicle (two wheels, four wheels) is advanced by repeating the stroke of "intake → compression → combustion → exhaust".

Fig. 1 shows an example of the configuration of the engine 1 and the control device 100, for example, except for a throttle opening degree signal, an engine rotation signal, and O₂In addition to the sensor output signal, the control device 100 may control the engine 1 by referring to the intake air temperature, the cooling water temperature, and the like of the engine 1. That is, in order to improve drivability, the types of sensors may be increased to calculate engine parameters such as an air-fuel ratio correction coefficient.

(functional configuration of control device 100)

Fig. 2 is a functional configuration diagram of the ignition control system 80 including the control device 100. The control device 100 includes: feedback control unit 120, storage unit 130, fuel injection control unit 150, ignition control unit 160, ignition unit 170, reception unit 190, and misfire occurrence determination unit 180. The ignition control system 80 includes an ignition coil 185 and an ignition plug 45 as objects to be controlled by the control device 100. The spark plug 45 has a spark gap at its tip end for spark discharge.

The storage unit 130 includes: program 132, map 134, nonvolatile storage 136, and work 138. The operating area 138 is a temporary storage area for temporarily storing various parameters and the like during an operation process and the like, and the nonvolatile storage area 136 is a storage area for nonvolatilely storing various parameters and the like of a fuel injection amount correction value.

The feedback control part 120 obtains the sum of the sum and the sum of the sum₂O of sensor 28₂The control deviation between the actual air-fuel ratio corresponding to the sensor output signal and the target air-fuel ratio is obtained, and a fuel injection amount correction value is obtained so that the obtained control deviation becomes zero. The fuel injection control unit 150 determines the fuel injection amount based on the throttle opening degree signal output from the throttle opening degree sensor 26 and the fuel injection amount correction value determined by the feedback control unit 120. The fuel injection control unit 150 gives a fuel injection control signal corresponding to the determined fuel injection amount to the injector 40 at a timing based on the engine rotation signal from the electromagnetic pickup 22. That is, the fuel injection control unit 150 obtains the fuel injection amount and supplies the fuel injection control signal corresponding to the obtained fuel injection amountA number is given to the injector 40. Thereby, the injector 40 injects the fuel in the fuel injection amount corresponding to the fuel injection control signal.

The fuel injection control unit 150, for example, gives a fuel injection control signal to the injector 40 such that fuel is injected in half in each of the compression stroke and the exhaust stroke before the stroke determination of the engine 1 is completed, and fuel is injected in a lump in the exhaust stroke after the stroke determination is completed.

The ignition control section 160 determines the ignition timing based on the engine rotation signal from the electromagnetic pickup 22, generates an ignition control signal, and gives the ignition control signal to the ignition section 170. The ignition section 170 controls the on/off of the primary side current of the ignition coil 185 in accordance with the ignition control signal. The ignition coil 185 includes a primary side coil and a secondary side coil. When the ignition section 170 turns on the primary side current flowing through the primary coil, a current from a battery not shown in fig. 2 flows, and then the ignition section 170 performs cutoff control of the primary side current.

In the secondary side coil, a secondary side current is generated by on/off control of the primary side current. Then, the secondary side current is supplied to the ignition plug 45, and spark discharge is performed in the spark gap thereof. The receiving unit 190 receives the ignition noise radiated from the ignition plug 45 to the space by the spark discharge. The received ignition noise is sent to the misfire occurrence determination section 180. The misfire occurrence determination section 180 determines the misfire occurrence based on the radiated ignition noise.

Fig. 3 is a functional block diagram of the misfire occurrence determination section 180. The misfire occurrence determination section 180 includes: specific frequency component extracting section 186, amplifying section 187, and determining section 188. The specific frequency component extracting section 186 extracts the specific frequency component of the ignition noise received by the receiving section 190. The amplification unit 187 amplifies the specific frequency component of the ignition noise extracted by the specific frequency component extraction unit 186. Instead of the amplifier 187, an attenuation unit may be provided at a stage subsequent to the specific frequency component extraction unit 186 to attenuate the specific frequency component of the ignition noise extracted by the specific frequency component extraction unit 186.

The judging section 188 judges the occurrence of misfire based on the output from the amplifying section 187 (or the output from the damping section). In this way, the precision of determining the occurrence of misfire is improved because only the frequency component of the ignition noise is extracted and the other noise components are removed from the ignition noise received by the receiving unit 190.

The receiving unit 190 may be implemented by, for example: a conductor pattern formed of a conductive material on an insulating substrate of a Printed Circuit Board (PCB), an inductance element such as a coil, a resistor having an inductance component, and the like. As a result, the receiving unit 190 can be realized by an antenna mounted on a printed circuit board on which the control device 100 is mounted. As a result, the control device 100 capable of judging the occurrence of misfire can be realized with a small and simple configuration. Further, since the operation program for misfire occurrence determination is simple, a device capable of misfire occurrence determination can be realized at an extremely low cost. Further, the occurrence of misfire can be judged by utilizing the ignition noise that has been inevitably generated conventionally.

(hardware constitution)

Fig. 4 is a hardware configuration diagram of the control device 100. The control device 100 includes: a Central Processing Unit (CPU) 200 having a ROM210 mounted thereon, a Random Access Memory (RAM) 220, and a flash Memory 230. Further, the control device 100 includes: a pre-driver 315, an ignition coil driver circuit 320, an antenna 330, a BPF (Band Pass Filter) 310, and an amplifier circuit 300.

Further, the ignition control system 80 includes: an ignition coil 185 including a primary side coil T1 and a secondary side coil T2; and an ignition plug 45 having a spark gap at a tip end thereof. Further, a battery 400 is provided, and its positive terminal is connected to the ignition coil 185 and to a predetermined portion of the control device 100 to supply power. The negative terminal of the battery 400 is grounded.

Various sensor signals are input to the CPU 200. Sensor signals are a throttle opening degree signal from a throttle opening degree sensor 26, an engine rotation signal from an electromagnetic pickup 22, and a signal from O₂O of sensor 28₂Sensor output signals, etc. On the other hand, the CPU200 is connected toThe injector 40 outputs a fuel injection control signal and an ignition control signal to the ignition control system 80.

The CPU200 reads out the program 132 recorded in the ROM210, and executes the program 132 while using the work area 138 and the like formed in the RAM 220. During the execution, the calculated fuel injection amount correction value or the like is updated and stored in the nonvolatile storage area 136 of the flash memory 230. The CPU200 can realize the feedback control unit 120, the fuel injection control unit 150, the ignition control unit 160, and the like shown in fig. 2 by executing the program 132 recorded in the recording medium such as the ROM 210. Further, the ROM210, the RAM 220, and the flash memory 230 realize the storage section 130.

The pre-driver 315 is a drive circuit for driving the ignition coil drive circuit 320 based on the ignition control signal output from the CPU 200. The pre-driver 315 is configured to have a plurality of transistors, for example, and boosts the ignition control signal output from the CPU 200. The ignition coil drive circuit 320 includes a transistor TR1, and the transistor TR1 is connected to a gate and an emitter through a resistor R2, and includes a protection resistor R1 at a gate terminal. The Transistor TR1 is an Insulated Gate Bipolar Transistor (IGBT) or the like as a power element. For example, the resistor R1 is 1(k Ω), and the resistor R2 is 16(k Ω).

The resistor R2 having a gate connected to the emitter is fixed in potential when the input high impedance of the IGBT TR1 is achieved, and the resistor R1 having the pre-driver 315 connected to the gate determines the input voltage of the IGBT TR1 by combination with the resistor R2.

One end of the primary coil T1 is connected to a collector of the transistor TR1, and a positive terminal of the battery 400 is connected to a connection point of the primary coil T1 and the secondary coil T2. On the other hand, the ignition plug 45 is connected to one end of the secondary coil T2, and the secondary current of the ignition coil 185 can be supplied to the ignition plug 45.

The antenna 330 can be implemented by, for example, an inductance element such as a coil, a resistor having an inductance component, or the like, in addition to a microstrip antenna which can be implemented by printed wiring on a Printed Circuit Board (PCB). One end side of the antenna 330 is grounded, and the other end side is connected to one end side of the capacitor C1 of the BPF 310.

Fig. 6 is a schematic diagram of the antenna 330. FIG. 6(a) is a plan view, and FIG. 6(b) is a sectional view taken along line A-A. The antenna 330 shown in fig. 6 is a patch-type (microstrip-type) antenna, and is formed by forming a conductor pattern 510 on an insulating substrate 500 of a Printed Circuit Board (PCB). The conductor pattern 510 has a length "L" and a width "W". For example, when receiving the ignition noise at a frequency of 4(kHz), the frequency of the ignition noise is multiplied by 10⁶The width W is a value of about 1 to 2(mm), where L is (1/4) × λ (wavelength) ═ 18.75(mm) ". When it is not appropriate to perform frequency doubling in a noise band, an inductance element, a resistor having an inductance component, or the like can be used.

The ignition noise that is the subject of reception by the antenna 330 is a harmonic of a frequency higher than its fundamental frequency. For example, when the antenna is designed to receive a fundamental frequency of 4(kHz), the antenna length and the substrate size become large. When the fundamental frequency is 4(kHz), the quarter wavelength is "18737029 (mm)", and therefore, it is preferable to design an antenna with a high frequency as a reception target.

The BPF 310 is an active filter with an operational amplifier 302. The non-inverting terminal of the operational amplifier 302 is grounded. On the other hand, a parallel circuit of a capacitor C2 and a resistor R3 is connected between the inverting terminal and the output terminal of the operational amplifier 302. Further, a capacitor C1 is also connected to the inverting terminal of the operational amplifier 302, and one end side of the capacitor C1 is connected to one end side of the antenna 330.

Fig. 5 shows an example of the frequency characteristic of the BPF 310 with the horizontal axis as frequency and the vertical axis as amplification degree. The frequency characteristic shown in fig. 5 is a characteristic of a typical band-pass filter, that is, the amplification degree at the center frequency is maximized, and the amplification degree becomes smaller as the filter moves to the low-side and the high-side. For example, when the resistor R3 is set to 30(k Ω), and the capacitors C1 and C2 are set to 0.68(nF) and 15(nF), respectively, the center frequency can be set to 4 (kHz). The center frequency can be adjusted by adjusting the values of the resistor R3, the capacitor C1, and the capacitor C2.

The amplifier circuit 300 has an operational amplifier 301, and the non-inverting terminal of the operational amplifier 301 is grounded. On the other hand, a resistor R4 is connected to the inverting terminal of the operational amplifier 301, and a resistor R5 is connected between the inverting terminal and the output terminal. Since the operational amplifier 301 is negatively fed back through the resistor R5 and the non-inverting terminal is grounded, it is in a virtual ground state, and thus "Vin/R4 is Vout/R5(Vin and Vout are input voltage and output voltage)", and the absolute value a of the amplification degree of the amplifier circuit 300 is "a is R5/R4". For example, the resistance R4 is 1(k Ω), the resistance R5 is 3(k Ω), and "a" may be 3.0 ". The value of a can be adjusted by adjusting the values of the resistors R4 and R5.

(operational overview)

When a rectangular pulse type ignition control signal is output from the CPU200, the pre-drive section 315 amplifies the ignition control signal and inputs it to the gate terminal of the ignition coil drive circuit 320. Since a rectangular signal is input to the gate terminal of the transistor TR1, the ignition coil drive circuit 320 controls the transistor TR1 to be turned on and off. This controls the on/off of the collector current, and controls the on/off of the primary current flowing through the primary winding T1.

Accordingly, a current flows through the secondary side coil T2 for a predetermined period, and the current is supplied to the ignition plug 45. Thereby, spark discharge is performed in the spark gap of the spark plug 45. As a result, the ignition noise is generated and radiated into the space. On the other hand, when a misfire occurs in the ignition plug 45, the ignition noise is not emitted.

The antenna 330 receives the ignition noise radiated to the space, the BPF 310 extracts only a specific frequency component thereof, and the amplifying circuit 300 amplifies the extracted specific frequency component. When the output signal from the amplifier circuit 300 is equal to or greater than a predetermined value, the CPU200 determines that normal ignition is performed (no misfire occurs). On the other hand, when the output signal from the amplifier circuit 300 is smaller than the predetermined value, the CPU200 determines that a misfire has occurred. The prescribed value may be adjusted by a vehicle structure or the like.

Specifically, when a high signal is input to CPU200, it is determined that spark noise is normally generated and that normal ignition is performed. On the other hand, when the high signal from the operational amplifier 301 is not input to the CPU200, it is determined that misfire has occurred.

In the hardware configuration described above, the functions realized by the CPU200 by executing the program 132 correspond to the feedback control unit 120, the combustion injection control unit 150, and the ignition control unit 160 of the functional configuration diagram of fig. 2, respectively. The ignition coil driving circuit 320 corresponds to the ignition section 170, and the antenna 330 corresponds to the receiving section 190. The BPF 310 and the amplifier circuit 300 correspond to the specific frequency component extracting unit 186 and the amplifying unit 187 of the misfire occurrence determination unit 180, respectively. Further, the misfire determination function that the CPU200 can realize by executing the routine 132 corresponds to the determination section 188.

(detailed description of the invention)

Next, a detailed operation will be described with reference to the configuration diagram of fig. 4, the flowchart of fig. 7, and the waveform diagram of fig. 8. In each waveform diagram of fig. 8, the horizontal axis represents "time (sec)" and the vertical axis represents "voltage (V)". First, as shown in S1 of the flowchart of fig. 7, the primary side coil T1 is driven. When the CPU200 outputs the ignition control signal, the pre-driver 315 boosts the voltage to enhance the power. Fig. 8(a) shows an output waveform of the pre-driver 315 at this time, that is, a waveform of an input voltage to the gate terminal of the transistor TR1 of the ignition coil drive circuit 320.

When compared with the "0 (V) -5 (V)" rectangular output voltage outputted from the CPU200 at the normal time, the voltage rises to about 7 (V). As shown in fig. 8(a), after the CPU200 outputs the ignition control signal, the voltage rises at once at about 0.002(sec), and falls at once after about 0.012 (sec). Then, a signal having a waveform shown in fig. 8(a) is input to the gate terminal of the transistor TR1 via the protective resistor R1. Thus, the transistor TR1 is turned on/off, and thus, the current flowing from the battery 400 to the primary coil T1 of the ignition coil 185 is controlled to be turned on/off.

Fig. 8 b shows an example of the voltage waveform (ignition primary signal) of the primary winding T1 at this time. When the signal (gate signal) shown in fig. 8 a falls, the voltage of the primary winding T1 becomes a pulse and becomes a high voltage of 100(V) or more. Fig. 8 c shows an example of the voltage waveform (ignition secondary signal) of the secondary winding T2 at this time. In response to the primary side coil T1 becoming high voltage, a negative voltage of high voltage is generated in the secondary side coil T2. The magnitude of the voltage generated in the secondary winding T2 is 3000(V) or more.

Then, as shown in S2 of fig. 7, when the secondary side current flowing through the secondary side coil T2 is supplied to the ignition plug 45, spark discharge is generated in the spark gap of the ignition plug 45. During normal ignition, spark discharge is normally performed, and ignition noise, which is noise caused by spark discharge, is generated and radiated into a space. The ignition noise has harmonics of a degree greater than the second harmonic. On the other hand, when a misfire occurs, no spark discharge occurs in the spark gap of the ignition plug 45, and no ignition noise is generated.

Then, as shown in S3 of fig. 7, the antenna 330 receives the ignition noise. Then, the ignition noise received by the antenna 330 is extracted its specific frequency component by the BPF 310 (S4 of fig. 7), and the amplification circuit 300 amplifies the frequency component extracted by the BPF 310 (S5 of fig. 7). By removing components other than the specific frequency component as described above, the signal processing accuracy is improved.

The specific frequency can be set by performing frequency analysis on the level of the harmonic of the ignition noise by a spectrum analyzer or the like, and selecting a harmonic that is easy to perform signal processing. In S5, when the ignition noise is too strong, an attenuation circuit may be provided in the subsequent stage of the BPF 310 in place of the amplification circuit to attenuate the frequency component extracted by the BPF 310.

Then, as shown in S6 and S7 of fig. 7, when the output level of the amplifier circuit 300 is equal to or higher than a predetermined value, it is determined as "normal ignition". On the other hand, as shown in S8 and S9, when the output level of the amplifier circuit 300 is less than the predetermined value, it is determined that a misfire occurred. That is, in the case of normal ignition, the output level of the amplifier circuit 300 is high because the spark plug 45 normally performs spark discharge, but in the case of misfire occurrence, the spark plug 45 abnormally performs spark discharge and there is no output from the amplifier circuit 300, so that it is possible to determine the misfire occurrence by using the ignition noise.

Specifically, the ignition noise received by the antenna 330 is input to the CPU200 operating at a voltage of 0(V) -5(V) by 5(V) at the time of normal ignition, and the input of 0(V) voltage to the CPU200 is continued at the time of occurrence of the misfire. When the instantaneous rise of the voltage of 5(V) is detected at the time of normal ignition, the CPU200 determines that the ignition is successful. At this time, the amplification factor of the amplifier circuit 300 (or the attenuation factor of the attenuation circuit) is set so that the input level to the microcomputer becomes 5 (V).

In the configuration in which the amplifier circuit 300 performs inverse amplification, a circuit for further inverting the signal subjected to inverse amplification may be provided in a subsequent stage of the amplifier circuit 300, or the CPU200 may perform processing for converting the output signal of the amplifier circuit 300 into an absolute value.

As described above, the ignition coil drive circuit 320 controls the on/off of the primary side current of the ignition coil 185 based on the ignition control signal output from the CPU200, and the antenna 330 receives the ignition noise radiated from the ignition plug 45 into the space by the control operation of the ignition coil drive circuit 320. Then, the CPU200 determines that misfire occurred based on the radiated ignition noise. More specifically, the CPU200 determines that misfire occurred based on whether ignition noise is received. That is, CPU200 determines whether the ignition by ignition plug 45 is normal ignition or misfire occurrence based on whether or not the amplitude of the signal of amplifier circuit 300 corresponding to the presence or absence of the occurrence of the ignition noise exceeds a predetermined value for misfire determination.

As a result, the occurrence of misfire can be judged by using the ignition noise, and complicated software and the like are not necessary for judging the occurrence of misfire. In this way, the control device 100 capable of judging the occurrence of misfire can be realized at low cost.

The above operation has been described with respect to the control device 100 using a large number of analog circuits, but may be implemented by software processing as much as possible. For example, the BPF 310 may be configured by a digital filter, and noise obtained by analog-to-digital converting ignition noise received by the antenna 330 may be input to the digital filter, or an output signal of the digital filter may be amplified by a digital amplifier and input to the CPU 200. In this case, the ignition control signal output from the CPU200 may be amplified by a digital amplifier or the like capable of programming a gain, and the ignition coil driving circuit 320 may be directly driven. In this manner, control device 100 can be configured as digital equipment as possible, and the number of components that CPU200 can execute by program 132 can be increased as much as possible.

In addition, the following cases were studied: the accuracy of misfire occurrence determination is improved by setting the specific frequency to a predetermined frequency band having a center frequency of 4(kHz), and the resistance value, the capacitor capacitance value, the waveform, the specific frequency, and the like are all exemplified. When the resistance value, the capacitance value, or the like is variable, the specific frequency can be set in accordance with the vehicle environment or the like.

Although the above description has been made, the present invention is not limited to the above embodiment, and various modifications and changes can be made. For example, the CPU200 may store information related to the misfire occurrence, for example, the number of times of misfire occurrence within a predetermined period in the nonvolatile memory area 136 of the flash memory 230, (2) may provide a notification unit to notify information to alert the user when the misfire occurrence exceeds a predetermined number of times and the misfire occurrence is frequent within a predetermined period, and (3) may combine a High Pass Filter (HPF) and a Low Pass Filter (LPF) instead of the BPF.

Industrial applicability

As described above, the present invention can be applied to an engine control device and the like that determines the occurrence of misfire.

Description of the symbols

1: engine

22: electromagnetic pickup

26: throttle opening sensor

28：O₂Sensor with a sensor element

40: ejector

45: spark plug

100: control device

120: feedback control unit

130: storage unit

132: procedure for measuring the movement of a moving object

136: nonvolatile memory area

150: fuel injection control unit

160: ignition control unit

170: ignition part

180: misfire occurrence determination section

185: ignition coil

190: receiving part

300: amplifying circuit

310：BPF

320: ignition coil drive circuit

330: antenna with a shield