JP6519306B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device of an internal combustion engine.

  Conventionally, in view of the large influence of the temperature of the internal combustion engine on the combustion state of the internal combustion engine, various controls of the internal combustion engine, such as fuel injection control, have been implemented based on the temperature of the internal combustion engine. For example, in order to detect the cooling water temperature of the internal combustion engine having a correlation with the temperature of the internal combustion engine, a temperature sensor is attached to the internal combustion engine, and fuel injection is controlled based on the detection result of the temperature by the temperature sensor.

  However, when a temperature sensor is provided to grasp the temperature of the internal combustion engine, a processing step for attaching the temperature sensor to the internal combustion engine is added, and attachment parts such as wires for wiring are added. As a result, the cost of the control device for the internal combustion engine is increased.

  Therefore, Patent Document 1 proposes that the engine temperature be calculated using the coil resistance value of a crank angle sensor which is directly mounted on the engine body and has a correlation with the engine temperature.

JP 2014-206144 A

  The coil resistance value of the crank angle sensor has variations due to individual differences. In addition, coil resistance may change due to aging and the like. Therefore, when calculating the engine temperature using the coil resistance value of the crank angle sensor, it is necessary to consider such variations in the coil resistance value.

  The present invention has been made in view of the above, and it is an object of the present invention to provide a control device of an internal combustion engine which can estimate the engine temperature with high accuracy while simplifying the configuration.

  The present invention uses the electrical functional component (29, 60) provided in the internal combustion engine (10) or in the vicinity thereof and having a predetermined detection function or operation function, and the detection function or operation function of the functional component. In a control device (70) for an internal combustion engine that controls an operating state of the engine, resistance detection means for detecting a resistance value of a resistor (61) of the functional component having a correlation with a temperature change of the internal combustion engine; Acquisition of the detected temperature from resistance temperature calculation means for calculating the resistance temperature which is the temperature of the resistor based on the detection result of the above and temperature detection means (74b) for estimating the outside air temperature under the cold condition of the internal combustion engine Learning value calculating means for calculating a difference between the resistance temperature calculated by the resistance temperature calculating means and the detected temperature obtained by the acquiring means as a learning value under a predetermined condition, and the learning value Based on the a resistance temperature compensation resistance temperature after correction by, characterized in that it comprises, and engine temperature calculation means for calculating the temperature of the internal combustion engine.

  According to the present invention, since the temperature of the internal combustion engine is calculated based on the corrected resistance temperature which is the resistance temperature corrected by the learning value, the variation due to the individual difference of the functional component resistors is removed. The temperature of the internal combustion engine can be calculated accurately.

The block diagram of an engine control system. The electric block diagram which shows the circuit structure of a control part. The figure which shows the mounting state of the circuit of a control part. The time chart which shows the relationship between an engine operating state and various temperature. The figure which shows the relationship between coil resistance value and coil temperature. The figure which shows the relationship between the elapsed time from engine stop, and correction value alpha. The figure which shows the relationship between coil temperature rise value and temperature addition value (beta). The flowchart which shows the processing procedure of ECU. The flowchart which shows the processing procedure of ECU.

  An embodiment in which a control device according to the present invention is applied to a vehicle equipped with an air-cooled engine (internal combustion engine) will be described below with reference to the drawings. In the present embodiment, a four-stroke gasoline engine is assumed in which four strokes of intake, compression, expansion, and exhaust are operated as one combustion cycle. As a vehicle, a scooter that is a motorcycle is assumed, and the engine is a single cylinder engine. In the scooter, an engine is mounted below the seat, and the engine is covered by a shroud (cover member).

  In FIG. 1, in the intake passage 12 of the engine 10, the pressure (intake pressure) of the air cleaner 14, the throttle valve 16, the throttle sensor 17 for detecting the opening of the throttle valve 16, and the intake passage 12 are sequentially An intake pressure sensor 18 is provided to detect. The throttle valve 16 is a member for adjusting the amount of intake air to the combustion chamber 20 of the engine 10 by adjusting the opening degree (throttle opening degree). The throttle opening degree is adjusted in accordance with the operation of a throttle grip (not shown) operated by the user. Further, a bypass passage 22 is connected to the intake passage 12 so that the upstream side and the downstream side of the throttle valve 16 communicate with each other. The bypass passage 22 is provided with a solenoid valve 24 for adjusting the amount of intake air flowing through the bypass passage 22 in order to control the engine speed during idle operation of the engine 10.

  In the vicinity of an intake port on the downstream side of the intake pressure sensor 18 in the intake passage 12, a fuel injection valve 29 is provided which injects the fuel pumped up from the fuel tank 28 by the fuel pump 26 into the vicinity of the intake port. There is. The mixture of the fuel injected and supplied from the fuel injection valve 29 and the intake air is supplied to the combustion chamber 20 by the opening operation of the intake valve 32.

  The air-fuel mixture supplied to the combustion chamber 20 is ignited by the discharge spark of the spark plug 34 protruding into the combustion chamber 20 and is used for combustion. The energy generated by the combustion of the air-fuel mixture is taken out as rotational energy of the output shaft (crankshaft 38) of the engine 10 via the piston 36. A high voltage for ignition is applied to the ignition plug 34 by an ignition coil 35 as an ignition device. The mixture supplied to the combustion is discharged as exhaust gas into the exhaust passage 42 by the opening operation of the exhaust valve 40.

  A magnet type generator (hereinafter referred to as a rotor 50) provided with a projection for crank position signal on the outer periphery is attached to the crankshaft 38. As shown in FIG. 2, the outer peripheral portion of the rotor 50 is a detection target portion, and a plurality of protrusions 51 are provided on the outer peripheral portion at predetermined rotation angles. Further, at the outer peripheral portion of the rotor 50, a missing tooth portion 52 as a reference position is provided by dropping one (or two) of the plurality of protrusions 51 arranged at equal intervals. In the present embodiment, the protrusions 51 are basically provided at an equal interval of 30 ° CA, and the non-toothed portions 52 only have a 60 ° CA interval. The number and intervals of the protrusions 51 are arbitrary, and may be 10 ° CA intervals or 60 ° CA intervals.

  A crank angle sensor 60 as a rotation detection sensor is provided on the cylinder block 11 (engine main body) of the engine 10 at a position facing the outer periphery (protrusion 51) of the rotor 50. More specifically, the crank angle sensor 60 is provided in the crankcase portion of the cylinder block 11. The crank angle sensor 60 is a well-known electromagnetic pick-up type sensor, and generates a magnetic flux penetrating the coil 61 and an iron core (not shown), a detection coil (hereinafter referred to as a coil 61) provided around the iron core. And a magnet (not shown).

  The rotor 50 is rotated in conjunction with the rotation of the crankshaft 38. When the projection 51 on the outer periphery of the rotor 50 passes the position of the crank angle sensor 60, the unevenness of the projection 51 changes the magnetic flux passing through the coil 61 of the crank angle sensor 60 and the electromotive force is generated in the coil 61 by the action of electromagnetic induction. . In this case, by detecting the passage of the protrusion 51, the coil 61 outputs an alternating current signal (rotation angle signal) at a predetermined rotation angle cycle. The crank angle sensor 60 is attached to the base of the stator coil of the generator (ACG) provided in the vicinity of the engine other than the one directly mounted on the cylinder block 11 (engine body), and the rotation of the ACG rotor Or a crank angle sensor attached to the side of the crankcase cover.

  The exhaust passage 42 is provided with a three-way catalyst 46 for purifying NOx, HC, CO and the like in the exhaust gas. On the upstream side of the three-way catalyst 46, an oxygen concentration sensor (hereinafter referred to as an O2 sensor 48) that changes the output value in a binary manner in accordance with the oxygen concentration in the exhaust is provided.

  Further, in the vehicle (squater) of the present embodiment, a cooling device (cooling means) 49 for forcibly cooling the engine 10 disposed in the shroud is mounted. The cooling device 49 includes a mechanical fan device driven by the rotation of the engine 10 and has a known cooling fan connected to the crankshaft 38. The shroud is provided with an inlet for taking in the cooling air from the outside, and an outlet for discharging the cooling air, and when the cooling device 49 is driven, the inlet and the outlet are provided. The cooling air passes through the inside of the shroud through the

  The ECU 70 is configured as an electronic control unit including the microcomputer 71. The microcomputer 71 performs various engine control based on various programs and arithmetic expressions stored in the storage unit. In this case, the operation state of the engine 10 is controlled by controlling the operation of the fuel injection valve 29 and the ignition coil 35 based on the signals acquired by the various sensors described above. In the present embodiment, the fuel injection valve 29 and the ignition coil 35 correspond to functional components having a predetermined operation function, and the crank angle sensor 60 corresponds to a functional component having a predetermined detection function.

  The ECU 70 is mounted at a location that is not easily affected by the temperature of the engine 10, and is installed at a position above the engine 10, for example, under the seat of the vehicle. The ECU 70 is connected to a lamp 81, a meter 82, and the like in a display unit provided in the front portion of the vehicle.

  Inside the ECU 70, thermistors 74a and 74b for detecting the ECU temperature are provided. The thermistors 74a and 74b correspond to temperature detection means. The detected values of the temperatures of the thermistors 74a and 74b (hereinafter referred to as ECU temperature) are used to estimate the outside air temperature at the cold start of the engine 10, or to calculate the increase amount of fuel injection (increased amount at start). It is used.

  As shown in FIG. 3, the thermistors 74 a and 74 b are mounted on a control board CB housed in a housing 70 a of the ECU 70. When the thermistors 74a and 74b are built in the ECU 70, the influence of disturbance on the detected temperature can be suppressed, so that the outside air temperature can be estimated accurately.

  In addition to the microcomputer 71, a heating element PD such as a switching element that generates heat as the engine is operated is mounted on the control board CB. The thermistor 74a is mounted at a distance d1 from the heating element PD. The thermistor 74 b is mounted at a distance d 2 from the heating element PD. It is assumed that the distance d1 <d2. In this case, since the influence of the heat generation of the heating element PD on each thermistor 74a, 74b is different, there is a difference between the ECU temperature Th1 detected by the thermistor 74a and the ECU temperature Th2 detected by the thermistor 74b in the engine operating state. It will occur.

  More specifically, in FIG. 4, when the engine 10 is started at time t1 from a state in which the ECU temperature Th1 of the thermistor 74a and the ECU temperature Th2 of the thermistor 74b coincide with the outside temperature, heat generation occurs along with the engine operation. The heat of the element PD causes the ECU temperatures Th1 and Th2 to gradually rise. Under the present circumstances, since temperature rise of ECU temperature Th1 is larger than ECU temperature Th2, temperature difference (DELTA) Th will arise in ECU temperature Th1 and Th2.

  Thereafter, when the engine 10 is stopped at time t2, the heat generation of the heating element PD is also stopped, and the ECU temperatures Th1 and Th2 gradually decrease. Then, at time t3, when the ECU temperatures Th1 and Th2 decrease to the outside temperature of the vehicle, both the ECU temperatures Th1 and Th2 match.

  Therefore, the ECU 70 of the present embodiment determines whether the engine 10 is in the soak state by using such temperature characteristics of the thermistors 74a and 74b. That is, when the temperature difference between the thermistors 74a and 74b becomes less than a predetermined temperature (for example, less than 3 ° C.) after stopping the engine, it is determined that the engine 10 is sufficiently cooled (soak state).

  Further, the ECU 70 detects the resistance value of the coil 61 of the crank angle sensor 60 when the engine 10 is stopped and under the operating condition, and calculates the engine temperature Te based on the detected coil resistance value RS. That is, the crank angle sensor 60 is directly mounted on the cylinder block 11 (engine main body), and has a correlation with the engine temperature Te. Therefore, in the present embodiment, the temperature of the engine 10 is detected using the crank angle sensor 60. The configuration will be described below.

  First, the rotation detection function which is a basic function of the crank angle sensor 60 will be described. The waveform shaping circuit 62 is provided in the ECU 70, and the AC signal output from the crank angle sensor 60 is converted into a pulse signal in the waveform shaping circuit 62. Then, the microcomputer 71 calculates the engine rotation speed based on the interval (time interval) of the pulse signal input from the waveform shaping circuit 62.

  Further, in the rotor 50, the angular interval of the rotation angle signal is different between the non-toothed part 52 and the other part, and the microcomputer 71 differs in the interval of the pulse signal according to the angular interval of the rotation angle signal. Detection of a missing tooth position (reference position) is performed based on the occurrence.

  Next, a function of calculating the engine temperature Te by detecting the coil resistance value of the crank angle sensor 60 will be described. The ECU 70 includes an energizing unit 72 which is an energizing unit for energizing the coil 61, and an A / D circuit as a voltage detecting unit 73 which detects a voltage value applied to the coil 61 when the coil is energized by the energizing unit 72. The microcomputer 71 calculates the engine temperature Te based on the coil resistance value obtained based on the voltage value (equivalent value of the coil resistance) detected by the voltage detection unit 73 and the current value flowing to the coil 61. .

  The energizing unit 72 includes a constant voltage power supply 72a (voltage Vcc), PNP transistors 72b and 72c, a resistor 72d (resistance value R1) and a resistor 72e (resistance value R1), and a switch 72f. . The transistors 72b and 72c form a current mirror circuit, the bases of the transistors 72b and 72c are connected to each other, and the connection of the bases is connected to the collector of the transistor 72c. The emitters of the transistors 72b and 72c are connected to the constant voltage power supply 72a. A resistor unit 72e is connected to the collector side of the transistor 72c, and a voltage detection unit 73, a coil 61, and a waveform shaping circuit 62 are connected in parallel to the other end of the resistor unit 72e. On the other hand, a resistor 72d is connected to the collector side of the transistor 72b, and a switch 72f is connected to the other end of the resistor 72d. The switch 72 f is, for example, a semiconductor switch, and switches between the conductive state and the non-conductive state of the transistor 72 b based on a command signal from the microcomputer 71.

  With the above configuration, when the switch 72f is turned on and the transistor 72b is turned on, the transistor 72c is also turned on, and a current IS (IS = Vcc / R1) is output from the transistor 72b. A current IS2 (.apprxeq.IS) is output from the transistor 72c. The current IS2 is a coil current supplied to the coil 61. The current IS ≒ IS2, and the coil current can be obtained as IS2 = IS = Vcc / R1. Further, a coil voltage VRS applied to the coil 61 is detected by the voltage detection unit 73. Thus, the microcomputer 71 calculates the coil resistance value RS as RS = VSR / IS2.

  FIG. 4 shows a time chart showing changes in the engine temperature Te and the coil temperature Tc. Here, the engine temperature Te is the temperature of the engine main body near the combustion chamber 20, that is, the temperature around the combustion chamber of the cylinder head and the cylinder block. In this chart, the engine 10 is started in a cold state at time t1, and thereafter, the operation of the engine 10 is stopped at time t2. After time t2, the engine is in the stopped state (soak state).

  In FIG. 4, at the time of engine start at time t1, the engine temperature Te and the coil temperature Tc coincide with each other. Further, these temperatures Te and Tc coincide with the outside air temperature (ie, the ECU temperature at the time of engine start). Then, as the operation of the engine 10 is started, the engine temperature Te and the coil temperature Tc rise. During engine operation (t1 to t2), air cooling of the engine 10 is performed by the cooling device 49, and the air cooling limits the temperature rise of each temperature Te, Tc. In this case, there is a difference in the degree of cooling between the engine body and the crank angle sensor 60, and in the crank angle sensor 60, the cooling action by the fan cooling works more than in the whole engine. Therefore, there is a temperature difference between the engine temperature Te and the coil temperature Tc. That is, it is considered that sufficient cooling is not performed in the vicinity of the combustion chamber in the engine body, and a temperature difference occurs as illustrated.

  On the other hand, in the engine stop state after time t2, the engine 10 is cooled by natural heat radiation while the engine air cooling by the cooling device 49 is stopped. In addition, the coil temperature Tc temporarily rises due to the buildup heat in the shroud immediately after the engine stops, and gradually decreases with the engine temperature Te after reaching near the engine temperature Te. In this case, unlike during engine operation, the engine temperature Te and the coil temperature Tc substantially match.

  As described above, the relationship between the engine temperature Te and the coil temperature Tc is different between during operation and after stop of the engine 10. Therefore, during engine operation, although there is a correlation between the engine temperature Te and the coil temperature Tc, the temperature difference between the engine temperature Te and the coil temperature Tc is due to the cooling by the cooling device 49 (including the cooling by traveling wind). Is occurring (temperature does not equal). On the other hand, after the engine is stopped, the engine temperature Te and the coil temperature Tc substantially match (the temperatures become the same) except for a predetermined period immediately after the stop.

  In the present embodiment, when the microcomputer 71 calculates the engine temperature Te using the coil resistance of the crank angle sensor 60, the coil resistance value RS is taken into consideration while cooling by the cooling device 49 while the engine is operating. The engine temperature Te is calculated based on. If the engine is in the stopped state, the engine temperature Te is calculated based on the coil resistance value RS without taking into consideration the amount of cooling by the cooling device 49.

  More specifically, the microcomputer 71 uses the temperature characteristic RA of the crank angle sensor 60 shown in FIG. 5 (the correlation between the coil resistance value RS and the coil temperature Tc) in the engine stop state to determine the coil resistance value RS. The coil temperature Tc is calculated from The temperature characteristic RA in FIG. 5 is preset from the specifications of the crank angle sensor 60. Since the coil temperature Tc is approximately equal to the engine temperature Te, the coil temperature Tc is set as the engine temperature Te. The engine temperature Te may be directly calculated from the coil resistance value RS on the assumption that the coil temperature Tc ≒ the engine temperature Te. In the present embodiment, the detected voltage value by the voltage detection unit 73 is taken as the equivalent value of the coil resistance.

  However, immediately after the engine 10 is stopped, there is a period in which the coil temperature Tc has not reached near the engine temperature Te (see FIG. 4, immediately after time t2). Therefore, the calculation of the engine temperature Te may be temporarily prohibited only immediately after the engine stop, or the engine temperature Te may be calculated as Te = Tc + α. α is a correction value calculated based on, for example, the relationship of FIG. In FIG. 6, as the elapsed time is smaller, a larger value is calculated as the correction value α based on the elapsed time from the engine stop.

  On the other hand, during operation of the engine, the microcomputer 71 calculates the coil temperature Tc from the coil resistance value RS using the relationship shown in FIG. The engine temperature Te is calculated by adding the temperature addition value β, which is the equation (Te = Tc + β). In this case, the temperature addition value β may be calculated according to the increase value of the coil temperature Tc from the initial temperature based on the initial temperature at the time of engine start. Specifically, the temperature addition value β may be calculated based on, for example, the relationship shown in FIG. In FIG. 7, based on the coil temperature increase value, as the increase value increases, a larger value is calculated as the temperature addition value β. In this case, the coil temperature increase value and the temperature addition value β may be in a proportional relationship.

  Referring to FIG. 4, it is assumed that the initial temperature at engine start is “Ti”, the coil temperature increase value is “ΔTco”, and the temperature addition value β is “β1” at time tx during engine operation. In this case, the engine temperature Te at time tx is calculated as “Ti + ΔTco + β1”.

  During engine operation, coil 61 of crank angle sensor 60 is temporarily energized while rotor 50 is rotating, and in the energized state, a period during which the rotation angle signal, which is an AC signal, is not output. The coil resistance value RS may be detected in the (signal non-output period).

  By the way, the coil resistance Rc of the crank angle sensor 60 has a variation (a tolerance) due to individual product differences. Therefore, as shown in FIG. 5, the calculated value of the coil temperature Tc with respect to a certain coil resistance Rc may change between the temperature characteristic RAS and the temperature characteristic RSB. In particular, when an inexpensive (low accuracy) crank angle sensor 60 is used to reduce the cost, the variation (tolerance) may be large.

  Therefore, when the coil temperature Tc is calculated from the coil resistance value RS based on the preset temperature characteristic RA, an error occurs in the calculated value of the coil temperature Tc, which may affect the calculated value of the engine temperature Te There is.

  Therefore, in the present embodiment, the coil temperature Tc is corrected based on the temperature difference between the coil temperature Tc and the detection temperature of the thermistors 74a and 74b (that is, the ECU temperature) as a reference temperature after factory manufacture of the vehicle. Calculate the learning value LN. Then, by calculating the engine temperature Te using the coil temperature Tc after correction based on the learning value LN (hereinafter referred to as a correction coil temperature), an error component of the coil temperature Tc due to individual product differences of the crank angle sensor 60 It is possible to calculate the engine temperature Te in a corrected state. Although the ECU temperature as the reference temperature may be detected by any of the thermistors 74a and 74b, in the present embodiment, the temperature detected by the thermistor 74b which is less affected by the heating element PD is taken as the ECU temperature. Let that be the ECU temperature Th.

  The initial learning before the vehicle is shipped is as follows. First, when the ECU 70 is first activated (IG turned on) before the vehicle is shipped to the market and the newly mounted crank angle sensor 60 is used for the first time, the microcomputer 71 acquires the ECU temperature Th detected by the thermistor 74 b. At the same time, the coil temperature Tc is calculated from the output voltage (coil resistance value RS) of the crank angle sensor 60 using the temperature characteristic RA of FIG. Then, a difference ΔT between the ECU temperature Th and the coil temperature Tc is calculated (ΔT = Tc−Th), and stored as a learning value LN.

  Then, after shipping the vehicle in the market, the microcomputer 71 calculates the engine temperature Te based on the correction coil temperature calculated by correcting the coil temperature Tc with the learning value LN (Te = Tc−LN). As described above, by calculating the engine temperature Te using the correction coil temperature, it is possible to calculate the engine temperature Te in a state where the variation due to the individual product difference of the crank angle sensor 60 is suppressed.

  By the way, if the learning value LN is not calculated correctly, the engine temperature Te will be calculated incorrectly. For example, at the time of calculation of the learning value LN, if the engine 10 is in the warm-up state and the ECU temperature Th and the coil temperature Tc are affected, the erroneous learning value LN is calculated.

  Therefore, after calculation of the learning value LN, the microcomputer 71 determines whether the temperature difference between the ECU temperature Th and the correction coil temperature is equal to or greater than a predetermined value each time the ECU 70 is started, and the temperature difference is predetermined. The learning value LN at the present time is updated when the occurrence frequency determined to be above becomes the predetermined high frequency. That is, when the temperature difference within a predetermined range, ie, the same temperature difference, is repeatedly generated as the temperature difference between the ECU temperature Th and the correction coil temperature, relearning is performed on the learning value LN.

  That is, when the temperature difference between the ECU temperature Th and the correction coil temperature frequently exceeds a predetermined value when the ECU 70 is activated, it is assumed that the cause of the temperature difference is due to the warm-up of the engine 10 It is thought that there is a high possibility that there is a problem with the learning value itself. In this case, a relearning process is performed. For example, when the temperature difference between the ECU temperature Th and the correction coil temperature becomes equal to or greater than a predetermined value continuously when the ECU 70 is activated a plurality of times, the relearning process is performed.

  In addition, when the vehicle is used for a long time, the temperature characteristics of the coil resistance Rc may change with the aged deterioration of the crank angle sensor 60 (such as the coil resistance and the deterioration of the wiring member such as the wire harness). As described with reference to FIG. 5, with the aged deterioration of the crank angle sensor 60, the correlation between the coil resistance Rc and the coil temperature Tc may change (e.g., shift to the temperature characteristic RSB side). In this case, it is necessary to correct the learning value LN.

  So, in this embodiment, the update condition of the learning value LN is defined, and when the update condition is satisfied, the update process which updates the learning value LN is performed. Specifically, when the update conditions shown in the following (a) and (b) are satisfied, it is considered that the temperature relationship between the ECU temperature Th and the correction coil temperature is not in a normal state, and the learning value LN is updated.

  (A) In the case where the ECU temperature Th is determined to be equal to the outside air temperature, the correction coil temperature is in a predetermined low temperature range (for example, 3 ° C. or less than Th) lower than the ECU temperature Th The learning value LN is updated on the assumption that the update condition is satisfied. That is, although the temperature of only the ECU 70 may rise due to the influence of self-heating, solar radiation, etc., the temperature of the crank angle sensor 60 does not become higher than the predetermined temperature. Further, since the crank angle sensor 60 is attached to the cylinder block 11 and affected by the heat generation of the engine 10, the coil temperature Tc exceeds the tolerance (for example, 3 ° C.) and becomes lower than the ECU temperature Th. There is no. Therefore, when the correction coil temperature becomes lower than a predetermined temperature with respect to the ECU temperature Th, the learning value LN is updated on the assumption that the temperature characteristic of the coil resistance Rc has changed.

  (B) It is learned that the update condition is satisfied when the correction coil temperature is in a predetermined high temperature range (for example, 40 ° C. or more higher than Th) higher than the ECU temperature Th in the operating state of the engine 10 Update the value LN. That is, considering that engine cooling is performed at the time of engine operation, coil temperature Tc becomes high temperature exceeding a predetermined temperature difference upper limit (for example, 40 ° C.) with respect to ECU temperature Th even during engine operation. There is nothing to do. Therefore, when the correction coil temperature becomes higher than a predetermined value with respect to the ECU temperature Th, the learning value LN is updated on the assumption that the temperature characteristic of the coil resistance Rc has changed.

  When the update condition is satisfied, the current learning value LN (i-1) is updated based on the difference ΔT (ΔT = Tc−Th) between the ECU temperature Th and the coil temperature Tc, and a new learning value LN is obtained. Calculate (i). For example, ΔT is multiplied by a predetermined weighting coefficient, and the product is added to the learning value LN (i−1) to calculate a new learning value LN (i). The updated value per time may be a constant value. In addition, an upper limit may be set for the update width.

  In the case of (b), it is necessary to distinguish between the increase of the coil temperature Tc due to the aged deterioration of the crank angle sensor 60 and the increase of the coil temperature Tc due to the engine warm-up. Therefore, in the present embodiment, the learning value LN is updated when it is determined that the state in which the temperature relationship between the ECU temperature Th and the correction coil temperature is not normal is repeated a plurality of times each time the engine is started. In this case, it is possible to update the learning value LN by distinguishing the change of the coil resistance Rc due to the influence of the engine warm-up and the change of the coil resistance Rc accompanying the aged deterioration.

  Furthermore, it is assumed that the crank angle sensor 60 may be replaced by a user, a dealer operator, or the like after the vehicle is shipped to the market, and the learning value LN is deleted and recalculated upon the replacement. That is, as described above, there are individual differences in the coil resistance of the crank angle sensor 60 (see FIG. 5). Therefore, when the crank angle sensor 60 is replaced and the temperature characteristic of the coil resistance changes, it is necessary to recalculate the learning value LN. Under the present circumstances, in order to reduce the cost in vehicle maintenance, it is desirable to determine with the crank angle sensor 60 having been replaced using the existing component in a self-vehicle, without using a dedicated diagnostic tool.

  In the present embodiment, the procedure for replacing the crank angle sensor 60 is defined in advance, and the user or the like carries out the task of replacing the crank angle sensor 60 in accordance with the procedure for replacing. Specifically, as an operation procedure at the time of replacement of crank angle sensor 60, an operation for setting the output value (coil voltage VRS) of crank angle sensor 60 to an emergency value not used in a normal state is defined. It is determined that the crank angle sensor 60 has been replaced based on the fact that the resistance value of the crank angle sensor 60 at the time of startup of the ECU 70 is an emergency value that is not a normal state. Then, when it is determined that the crank angle sensor 60 has been replaced, the current learning value LN is erased, and thereafter, a new learning value LN is calculated (that is, relearning is performed).

  For example, when replacing the crank angle sensor 60, it is defined as an operation procedure to turn on the ignition with the crank angle sensor 60 removed. In this case, the sensor output immediately after the ignition is turned on is the output voltage (for example, 5 V) at the time of disconnection. Therefore, when the microcomputer 71 detects this abnormal output voltage, it determines that the crank angle sensor 60 has been replaced, assuming that the resistance value of the crank angle sensor 60 is an emergency value.

  In addition, after the crank angle sensor 60 is removed, it may be defined as an operation procedure to connect an output device for outputting a special signal to the sensor connector. The output device alternately outputs, for example, on / off signals (0 V, 5 V). In this case, the sensor output immediately after the ignition is turned on is an emergency value that can not be normally achieved. Therefore, the microcomputer 71 may determine that the crank angle sensor 60 has been replaced based on the emergency value.

  If it is determined that the crank angle sensor 60 has been replaced, the current learning value LN is deleted, and then a new learning value LN is calculated. For example, as a series of procedures accompanied by the elimination of the learning value LN, a new learning value LN is calculated before the ignition is switched off. Alternatively, after the learning value LN is erased, once the ignition is turned off, the new learning value LN is calculated when the ignition is turned on next time (when a predetermined condition is satisfied). It is also good.

  As described above, relearning can be performed without using a dedicated diagnostic tool. In addition, since relearning is performed on condition that a predetermined replacement procedure is performed by the user or the like, when the user or the like removes the crank angle sensor 60 for the purpose other than the replacement of the crank angle sensor 60, the relearning is erroneously performed again. Learning can be avoided.

  Further, the microcomputer 71 notifies that the calculation of the learning value LN requires at least a new calculation (relearning) of the learning value LN, and that the calculation of the learning value LN is completed. Use to inform the user. For example, the learning state is notified by the blinking state of the lamp 81 provided on the display unit of the own vehicle, the code display on the meter 82, or the like. As a result, the user can recognize the necessity of relearning, the implementation situation of relearning, and the like by confirming the information of the display unit.

  Next, procedures of various processes performed by the microcomputer 71 will be described. FIG. 8 is a flowchart of the learning process. FIG. 9 is a flowchart related to replacement determination processing of the crank angle sensor 60. The following processing is performed after an ignition switch (not shown) is switched on.

  In the learning process of FIG. 8, it is first determined whether or not the ignition switch has just been switched on (S10). Then, immediately after the switching, the coil voltage VRS of the crank angle sensor 60 is obtained (S11), and the coil temperature Tc of the crank angle sensor 60 is calculated based on the coil voltage VRS (S12). Further, the ECU temperature Th is acquired (S13).

  Thereafter, it is determined whether an execution condition of the first learning is satisfied (S14). The implementation condition of the initial learning is a condition for determining whether or not to perform the initial learning to be implemented after the crank angle sensor 60 is installed, and the condition at the time of the first ignition on (initial activation) before factory shipment of the vehicle. It is determined that the condition has been established. Further, in the present embodiment, the learning value LN is erased along with the replacement of the crank angle sensor 60, and it is determined that the condition is satisfied even when the ignition is turned on for the first time after the replacement of the crank angle sensor 60. Be done.

  When affirming S14, an initial learning is carried out (S15). At this time, on the condition that the ECU temperature Th is equal to the outside air temperature, the learning value LN is calculated from the difference ΔT between the ECU temperature Th and the coil temperature Tc and stored in the memory. Thereafter, the lamp 81 blinks or the like to notify that the first learning has been completed (S16). After calculation of the learning value LN, the engine temperature Te is calculated based on the coil temperature Tc (correction coil temperature) after correction using the learning value LN.

  In addition, when S14 is denied, it is determined whether an execution condition of relearning is satisfied (S17). The execution condition of the relearning is a condition for determining whether or not the learning value LN is correctly calculated when the learning value LN already exists, and for example, the learning value LN is erroneously calculated in the first learning. Be affirmed if With regard to the determination, specifically, it is determined whether or not the temperature difference between the ECU temperature Th and the correction coil temperature is equal to or greater than a predetermined value when the ECU 70 is activated, and the temperature difference is determined to be equal to or greater than the predetermined When the occurrence frequency is a predetermined high frequency, it is determined that the learning value LN is not correctly calculated.

  When affirming S17, the present learning value is updated (S18). At this time, the current learning value LN is erased, and a new learning value LN is calculated from the difference ΔT between the ECU temperature Th and the coil temperature Tc and stored in the memory (relearning). Thereafter, the lamp 81 blinks or the like to notify that the relearning has been completed (S19). Note that the notification when the first learning is completed (S16) and the notification when the relearning is completed may be performed in the same notification mode, or may be performed in different notification modes so that they can be distinguished. May be

  If both S14 and S17 are negative, it is determined whether the update condition of the learning value LN is satisfied (S20). The conditions for updating the learning value LN are as described above, and under the condition that the ECU temperature Th ≒ the outside temperature, the coil temperature Tc is lower than the ECU temperature Th in a predetermined low temperature range (eg, 3 ° C. or less than Th). If it is, it is determined that the update condition is satisfied. Alternatively, when the correction coil temperature is in a predetermined high temperature range (for example, 40 ° C. or more higher than Th) higher than the ECU temperature Th in the operating state of the engine 10, the update condition is considered to be satisfied. .

  When affirming S20, the process of updating the learning value LN is performed (S21). At this time, a new learning value LN (i) is calculated based on the learning value LN (i-1) at the current time and the difference ΔT between the ECU temperature Th and the coil temperature Tc, and the learning value LN (i) is calculated. Update the current learning value LN (i-1). Note that the notification by the lamp 81 or the like may be performed also when the learning value LN is updated.

  Further, in the replacement determination process of the crank angle sensor 60 of FIG. 9, it is determined whether or not the ignition switch has just been switched on (S30). Then, if it is immediately after the switching, the coil voltage VRS of the crank angle sensor 60 is acquired (S31). Thereafter, whether or not the crank angle sensor 60 has been replaced is determined based on whether or not the coil voltage VRS is an emergency value not used in a normal state (S32).

  When affirming step S32, the learning value LN is deleted (S33). Thereafter, the fact that the learning value LN has been erased is notified by blinking of the lamp 81 or the like, and the exchange history is stored in the memory (S34). Note that the notification mode at the time of elimination of the learning value LN may be different from the notification mode at the time of initial learning or relearning.

  According to the above, the following excellent effects can be achieved.

  The temperature (coil temperature Tc) of the coil resistance Rc is calculated from the resistance value of the coil resistance Rc of the crank angle sensor 60 having a correlation with the temperature change of the engine 10, and the engine temperature Te is calculated from the coil temperature Tc it can. However, the resistance value of the coil resistance Rc of the crank angle sensor 60 has variations due to individual product differences. Therefore, when calculating the engine temperature Te using the coil temperature Tc, it is necessary to take into consideration the influence of variations due to individual differences in the coil resistance Rc. Therefore, under a predetermined condition, a temperature difference between the ECU temperature Th (the temperature detected by the thermistors 74a and 74b) and the coil temperature Tc is calculated as a learning value LN. Then, the engine temperature Te is calculated based on the coil temperature Tc corrected by the learning value. Therefore, the engine temperature Te can be accurately calculated in a state where variations due to individual differences in the coil resistance Rc of the crank angle sensor 60 are removed.

  If it is determined that the ECU temperature Th is equal to the outside air temperature, it is estimated that the engine 10 is sufficiently cooled. In this case, when the engine 10 is sufficiently cooled, it is considered that the ECU temperature Th and the coil temperature Tc are equal to each other. Under this condition, the learning value LN can be properly calculated.

  When the temperature difference with the ECU temperature Th correction coil temperature frequently occurs more than a predetermined value when the ECU 70 is started, it is difficult to assume that the cause of the temperature difference is due to the warm-up of the engine 10 , It is highly probable that there is a problem with the learning value itself. In this case, the calculation accuracy of the engine temperature Te can be enhanced by recalculating the learning value LN.

  The crank angle sensor 60 is attached to the cylinder block of the engine 10 and is affected by the heat generation of the engine 10, so the correction coil temperature exceeds the tolerance (for example, 3 ° C.) and becomes lower than the ECU temperature Th. There is nothing to do. When this point is taken into consideration, it can be understood that the calculation accuracy of the coil temperature Tc has decreased due to the change over time, etc., and the update processing as necessary can be performed for the learning value LN.

  -Considering that engine cooling is performed during engine operation, the correction coil temperature may exceed the predetermined temperature difference upper limit (for example, 40 ° C.) with respect to the ECU temperature Th to become high temperature even during engine operation. Absent. When this point is taken into consideration, it can be understood that the calculation accuracy of the coil temperature Tc has decreased due to the change over time, etc., and the update processing as necessary can be performed for the learning value LN.

  Since the resistance value of the coil resistance Rc has individual differences, the coil resistance value RS changes when the crank angle sensor 60 is replaced. Therefore, the learning value LN is recalculated with the replacement of the crank angle sensor 60. In this case, an appropriate learning value LN can be acquired in accordance with the coil resistance value RS of the crank angle sensor 60 after replacement. Further, in the two-wheeled vehicle, it is desirable that the ECU 70 be able to recognize various states of the vehicle without using a diagnostic tool or the like in order to reduce the cost. In this respect, according to the above configuration, when the crank angle sensor 60 is replaced, the replacement can be recognized by the ECU 70 using the output of the crank angle sensor 60.

  When the learning value LN is deleted and when the learning value LN is newly calculated, the user is notified of that effect. Thus, the user can grasp the state of implementation of learning in the vehicle.

  The thermistors 74a and 74b housed in the housing 70a of the ECU 70 are considered to be less susceptible to the influence of the external environment than the crank angle sensor 60, and to be relatively reliable. Therefore, the reliability of the learning value LN can be enhanced by calculating the learning value LN based on at least one of the thermistors 74a and 74b.

  The present invention is not limited to the above, and may be implemented as follows. In the following description, the same components as those described above are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

  When the process of S17 in FIG. 8 described above is affirmed, that is, the occurrence frequency at which it is determined that the temperature difference between the ECU temperature Th and the engine temperature Te after correction by the learning value LN is a predetermined value or more In the case where the frequency is high, even if the learning value at the current time is deleted and the new learning value LN is calculated, on the condition that the ECU temperature Th is equal to the outside temperature (being in the soak state) Good.

  -In the process of S14 of FIG. 8 described above, even when there is a history in which the learning value LN is intentionally erased by the user, it may be determined that the condition for performing the first learning is satisfied.

  The output value of the crank angle sensor 60 is normal when it is detected that the predetermined voltage is applied to the crank angle sensor 60 although the microcomputer 71 does not energize the crank angle sensor 60 in the above. It may be determined that the state is an emergency value not used.

  In the above, it is determined whether the engine 10 is in the soak state, using the temperature difference between the two thermistors 74a and 74b provided in the ECU 70. In addition to the above, among the temperature sensors mounted on a two-wheeled vehicle, a temperature sensor other than one for detecting the temperature of the engine 10 and capable of detecting the outside air temperature when the engine 10 is in a soak state It may be used to determine whether the engine 10 is in the soak state.

  In the above, the example of calculating the temperature of the engine 10 based on the resistance value of the coil 61 possessed by the crank angle sensor 60 has been described. Besides this, the engine temperature Te can be calculated based on the resistance value of the resistor of the electrically functional component that is provided at or near the engine 10 and has a correlation with the engine temperature Te and the temperature characteristic. For example, the engine temperature Te may be calculated using the resistance value of the resistor of the fuel injection valve 29 that injects the mixture of fuel and intake air into the combustion chamber 20 as the original operation function. In this case, the resistor (for example, a coil) of the fuel injection valve 29 is temporarily set by the energizing unit 72 at a timing such as the start of the engine 10 where the injection supply operation (the original operation function) of the fuel injection valve 29 is not performed. Electricity is supplied, and the engine temperature Te is calculated based on the voltage value (or resistance value) detected by the voltage detection unit 73. Besides this, the engine temperature Te may be calculated using the resistance value of a resistor such as a cam angle sensor provided in the cylinder block 11 of the engine 10 as a functional component.

  Also, as functional components, an ISC valve (solenoid valve 24) for adjusting the idle air amount, a secondary air valve for supplying the secondary air for catalyst warm-up to the exhaust passage 42, and an evaporation gas adsorbed on the canister the intake passage 12 It is possible to use a purge valve to supply the With respect to each of these functional components, the resistance value is acquired by energizing the resistor at the time of non-operation where the original operation function is not performed. The engine temperature can then be calculated based on the resistance value. The above-described ISC valve, secondary air valve, and purge valve are not directly mounted on the engine body but are provided in the vicinity of the engine body.

  If the energization of the functional component by the energizing unit 72 for detecting the resistance value does not affect the original operation function of the functional component, the original operation function of the functional component and the detection function of the engine temperature Te It may be done simultaneously. Moreover, as a resistor, the copper wire which comprises a functional component besides a coil can be used.

  In the above, an example is shown in which the outside air temperature is estimated based on the detection results of the temperatures by the plurality of thermistors 74a and 74b provided in the ECU 70 on the premise that the ECU 70 is in the soak state. It is not limited. For example, when the heat generation of the ECU 70 has little influence on the estimation of the outside air temperature, it is also possible to estimate the outside air temperature based on the detection result of the temperature of one thermistor provided in the ECU 70.

  The present invention can be applied to various vehicles and machines equipped with an engine, and can be applied to, for example, four-wheeled vehicles, industrial vehicles, construction machines such as cranes, agricultural machines such as tractors, and the like. Moreover, it is applicable also to the engine used for energy supply systems, such as cogeneration. Furthermore, the present invention can be applied to a vehicle equipped with a known engine, such as a water-cooled type engine, a multi-cylinder engine, etc. regardless of the type of engine.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 29 ... Fuel injection valve, 60 ... Crank angle sensor, 61 ... Coil, 70 ... ECU, 74a ... Thermistor, 74b ... Thermistor.

Claims (9)

The operating condition of the internal combustion engine using an electrical functional component (29, 60) provided in or near the internal combustion engine (10) and having a predetermined detection function or operation function, and the detection function or operation function of the functional component In a control device (70) of an internal combustion engine that controls
Resistance detection means for detecting the resistance value of the resistor (61) of the functional component having a correlation with the temperature change of the internal combustion engine;
Resistance temperature calculation means for calculating a resistance temperature which is a temperature of the resistor based on a detection result of the resistance value;
Acquisition means for acquiring a detected temperature from temperature detection means (74b) for estimating the outside air temperature under the cold condition of the internal combustion engine;
Learning value calculating means for calculating a difference between the resistance temperature calculated by the resistance temperature calculating means and the detected temperature obtained by the obtaining means as a learning value under predetermined conditions;
Engine temperature calculating means for calculating the temperature of the internal combustion engine based on the corrected resistance temperature which is the resistance temperature after correction by the learning value;
Equipped with
As a work procedure at the time of replacement of the functional part, a work of setting the resistance value of the functional part to an emergency value not used in a normal state is defined.
It comprises an exchange determination means for determining that the functional component has been replaced based on the fact that the resistance value of the functional component is the emergency value when the control device is started,
The learning value calculating means erases the learning value at the current time point when it is judged by the exchange judging means that the functional component has been exchanged, and then calculates a new learning value. Control device for an internal combustion engine. A first determination unit that determines whether the temperature detected by the temperature detection unit is equal to the ambient temperature;
The control device for an internal combustion engine according to claim 1, wherein the learning value calculation means calculates the learning value under the condition that the detected temperature and the outside air temperature are determined to be equal. A second determination unit that determines whether or not a temperature difference between the detected temperature and the correction resistance temperature is equal to or greater than a predetermined value when the control device is activated;
The learning value calculating means updates the learning value at the current time when the frequency of occurrence in which the temperature difference is determined to be equal to or more than the predetermined value by the second determining means is a predetermined high frequency. A control device for an internal combustion engine according to claim 1. A second determination unit that determines whether or not a temperature difference between the detected temperature and the correction resistance temperature is equal to or greater than a predetermined value when the control device is activated;
The learning value calculating means determines that the detected temperature is equal to the outside air temperature when the second determining means determines that the temperature difference is greater than or equal to a predetermined frequency as a predetermined high frequency. The control device for an internal combustion engine according to claim 1 or 2, wherein when it is determined, the learning value is deleted and a new learning value is calculated. The functional component is provided at a position that is more susceptible to the heat of the internal combustion engine than the temperature detection means,
In the case where the correction resistance temperature falls within a predetermined low temperature range lower than the detection temperature under the condition that the detection temperature is equal to the outside air temperature, the learning value calculation means The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the current learning value is updated based on a difference from a detected temperature.   When the correction resistance temperature is within a predetermined high temperature range higher than the detection temperature, the learning value calculation means determines the learning value at the present time based on the difference between the correction resistance temperature and the detection temperature. The control device for an internal combustion engine according to any one of claims 1 to 5, wherein With regard to the calculation of the learning value by the learning value calculating means, notifying means (81, 82) notify at least that a new calculation of the learning value is required and that the calculation of the learning value is completed. The control apparatus of the internal combustion engine of any one of Claim 1 thru | or 6 provided with alerting | reporting control means. The functional component is a rotation detection sensor (60) provided on an engine body of the internal combustion engine, which detects the rotation of the internal combustion engine,
The rotation detection sensor includes, as the resistor, a detection coil (61) that detects the rotation of the rotor (50) interlocked with the rotation of the internal combustion engine and outputs a rotation angle signal at a predetermined rotation angle cycle. ,
And an energizing means (72) for energizing the detection coil,
The resistance detection means detects a resistance value of the detection coil in a state where the detection coil is energized by the energizing means.
The control device of an internal combustion engine according to any one of claims 1 to 7 , wherein the temperature calculation means calculates the temperature of the internal combustion engine based on the detected resistance value of the detection coil. A control device (70) mounted on a control board and housed in the housing portion (70a) in a mounted state,
The control device of an internal combustion engine according to any one of claims 1 to 8 , wherein the temperature detection means is a temperature sensor (74b) provided in the housing portion.

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