JP2021004557A - Electrically-driven cam phase control device and engine control device - Google Patents

Abstract

To provide an electrically-driven cam phase control device and an engine control device enabling accurate control aligned with a cam control signal without degrading robustness as much as possible, and to provide an engine control device capable of accurately inputting an actual cam phase from the electrically-driven cam phase control device.SOLUTION: An electrically-driven cam phase control device measures a duty ratio of a directive PWM signal which corresponds to a cam control signal of an electrically-driven camshaft when the directive PWM signal is inputted from an engine control device (S32). The electrically-driven cam phase control device calculates a correction amount based on a difference between a duty ratio of the PWM signal and a predetermined reference value of a duty ratio set within a predetermined correction direction range when the duty ratio of the directive PWM signal is within the predetermined correction direction range (S35). The electrically-driven cam phase control device corrects the inputted directive PWM signal based on the correction amount (S39) and controls a cam phase using the corrected result (S40).SELECTED DRAWING: Figure 4

Description

The present invention relates to an electric cam phase control device and an engine control device.

The electric VCT (Variable Cam Timing) system grasps the operating state such as the number of revolutions and the accelerator opening in order to obtain an appropriate torque and output of the engine, and continuously controls the cam phase using a motor. This system has been developed as a device that optimizes the opening and closing timing of the intake valve that supplies air to the engine and the exhaust valve that discharges exhaust gas. Conventionally, in an electric VCT system, an electric cam phase control device inputs a control signal for exhaust valve control from an engine control device to perform substantial control. At this time, when the engine control device outputs the command PWM signal to the electric cam phase control device, the electric cam phase control device controls the cam phase of the electric camshaft based on the command PWM signal.

For example, in a system in which the engine control device performs open-loop control on the electric cam phase control device, the period of the PWM signal is between the command PWM signal output by the engine control device and the PWM signal input by the electric cam phase control device. When a pulse width (duty ratio) recognition error occurs, the electric cam phase control device cannot perform accurate control according to the cam control signal input from the engine control device due to the error.

On the other hand, the electric cam phase control device outputs the actual cam phase indicating the result of controlling the cam phase to the engine control device, but at this time, the same problem arises when inputting / outputting using the PWM signal. In this case, not only the robustness of the cam phase control is lowered, but also the accuracy requirement of the input or output PWM signal is increased, which leads to an increase in cost. Documents related to the present application are listed in Patent Document 1. The technique described in Patent Document 1 is a document relating to a PWM signal communication device.

Japanese Unexamined Patent Publication No. 5-2902042

A first object of the present disclosure is to provide an electric cam phase control device that can be accurately controlled according to a cam control signal, and an engine control device that transmits a cam control signal to the electric cam phase control device. A second object of the present invention is to provide an engine control device capable of accurately acquiring the actual cam phase from the electric cam phase control device.

The invention according to claim 1 is an object of an electric cam phase control device that controls a cam phase of an electric camshaft by inputting a cam control signal of the electric camshaft from an engine control device.
According to the invention of claim 1, when the measurement unit inputs a PWM signal for a command corresponding to the cam control signal of the electric camshaft from the engine control device, the measuring unit measures the duty ratio of the PWM signal (S32). When the duty ratio of the PWM signal is within the predetermined correction instruction range, the correction amount calculation unit corrects the amount based on the difference between the duty ratio of the PWM signal and the predetermined reference value of the duty ratio set in the predetermined correction instruction range. Is calculated (S35). The correction unit corrects the input PWM signal for the command based on the correction amount calculated by the correction amount calculation unit (S39). The control unit controls the cam phase using the correction result of the correction unit (S40). As a result, the electric cam phase control device can be accurately controlled according to the input cam control signal without deteriorating the robustness as much as possible.

Further, according to the invention of claim 7, after transmitting a cam control signal to the electric cam phase control device, the actual cam phase when the cam phase is controlled by the electric cam phase control device is PWMed from the electric cam phase control device. The target is an engine control device (14) that receives a signal and acquires the actual cam phase based on the received PWM signal.
When the PWM signal is input from the electric cam phase control device, the measuring unit measures the duty ratio of the PWM signal corresponding to the actual cam phase (S13). When the duty ratio of the PWM signal is within the predetermined correction instruction range, the correction amount calculation unit corrects the amount based on the difference between the duty ratio of the PWM signal and the predetermined reference value of the duty ratio set in the predetermined correction instruction range. Is calculated (S15). The correction unit corrects the actual cam phase acquired from the PWM signal based on the correction amount calculated by the correction amount calculation unit (S16). As a result, the engine control device can correct the actual cam phase acquired from the PWM signal, and the actual cam phase can be accurately acquired from the electric cam phase control device.

Schematic diagram of the engine system according to one embodiment Correspondence diagram showing the relationship between the duty ratio of the PWM signal and the cam phase A flowchart illustrating pre-start processing of the engine control device A flowchart illustrating pre-start processing of the electric cam phase control device. Timing chart showing changes in each counter value when transmitting and receiving PWM signal pulses A flowchart illustrating the normal processing of the engine control device A flowchart illustrating the normal processing of the electric cam phase control device. Control system block diagram Block diagram of the control system according to the comparative example

Hereinafter, an embodiment of the electric cam phase control device and the engine control device will be described with reference to the drawings.
FIG. 1 shows the configuration of an electric VCT system S (Variable Cam Timing System). A control system in which the drive source of the VCT system is operated by an electric actuator (see 15 in FIG. 1) is referred to as an electric VCT system S. The electric VCT system S is a system that optimizes the opening / closing timing of valves, and by this system, it is possible to reduce exhaust emissions, improve fuel efficiency by reducing pumping loss, and improve engine output by improving intake / exhaust efficiency.

Inside the engine body 1 as an internal combustion engine, an engine block 2, an intake path 3, an intake valve 4 arranged in the intake path 3, an exhaust path 5, an exhaust valve 6 arranged in the exhaust path 5, and a spark for ignition. A plug 7, a crankshaft 8, a piston 9, and the like are installed. A crank angle sensor 10 is installed on the outside of the crankshaft 8, and the crank angle sensor 10 is provided for detecting the position of the crankshaft 8.

The power of the crankshaft 8 is transmitted to the sprocket through a timing chain (not shown), and is transmitted to the intake camshaft 11 and the exhaust camshaft 12 as electric camshafts. An electric actuator 15 for adjusting the advance angle amount (VCT phase, relative rotation phase) of the intake camshaft 11 with respect to the crankshaft 8 is attached to the intake camshaft 11. The electric actuator 15 is, for example, a motor. The electric cam phase control device 13 controls the electric actuator 15 to transmit the cam rotation power to the intake camshaft 11 by using the power of the electric actuator 15, and the phase of the intake camshaft 11 (hereinafter referred to as a cam phase). To control.

An intake cam angle sensor 18 that outputs an angle pulse signal as an intake cam angle signal at a predetermined cam angle is attached to the outer peripheral side of the intake cam shaft 11. An exhaust cam angle sensor 19 that outputs an angle pulse signal as an exhaust cam angle signal at a predetermined cam angle is attached to the outer peripheral side of the exhaust camshaft 12. The exhaust cam angle sensor 19 is provided for detecting the position of the exhaust cam shaft 12, and is connected to the electric cam phase control device 13. Although schematically shown in FIG. 1, the intake cam shaft 11 and the exhaust cam shaft 12 are configured to have a common coaxial structure, and the intake cam and the exhaust cam are configured to be interlocked with each other in a coaxial structure. Is good. In this case, the configurations of the intake camshaft 11 and the exhaust camshaft 12 can be made common, and the intake cam angle sensor 18 and the exhaust cam angle sensor 19 can be made common by one cam angle sensor.

The electric cam phase control device 13 and the engine control device 14 are configured to include control bodies such as CPUs 13a and 14a, respectively, and are configured to operate based on their respective internal clocks. Although not shown, the electric cam phase control device 13 and the engine control device 14 include a timer and a communication device using a counter.

Each communication device of the electric cam phase control device 13 and the engine control device 14 is connected through a signal line 16. The engine control device 14 transmits a cam control signal to the electric cam phase control device 13 through the signal line 16. The electric cam phase control device 13 transmits information on the actual cam phase θc to the engine control device 14 through the signal line 16.

Further, the electric cam phase control device 13 is equipped with a CPU 13a and a storage unit 13b, and the engine control device 14 is equipped with a CPU 14a and a storage unit 14b. The storage unit 13b is a volatile storage unit 13c that can store various information while the power is turned on to the electric cam phase control device 13, and a non-volatile storage unit 13c that can non-volatilely store various information even when the power is cut off. A storage unit 13d is provided. The storage unit 14b is a volatile storage unit 14c that can store various information while the engine control device 14 is turned on, and a non-volatile storage unit that can non-volatilely store various information even when the power is cut off. It is equipped with 14d. Programs are stored in the non-volatile storage units 13d and 14d, respectively.

Further, in the non-volatile storage units 13d and 14d, accurate information on the H pulse width, period, and duty ratio of the PWM signal used at the time of correction is stored in advance as predetermined reference values within a predetermined correction instruction range. These stored information are predetermined information at the time of designing or manufacturing / inspection of the electric cam phase control device 13 and the engine control device 14.

The CPU 13a of the electric cam phase control device 13 realizes various functions (measurement unit, correction amount calculation unit, correction unit, control unit) by executing a program stored in the non-volatile storage unit 13d. The CPU 14a of the engine control device 14 realizes various functions (measurement unit, correction amount calculation unit, correction unit, abnormality presence / absence determination unit) by executing a program stored in the non-volatile storage unit 14d.

The intake cam angle sensor 18 and the exhaust cam angle sensor 19 detect the intake cam angle signal and the exhaust cam angle signal as cam sensor signals, respectively, and output the position detection signal to the engine control device 14. The crank angle sensor 10 outputs a crank pulse signal detected at a predetermined crank angle to the engine control device 14 as a crankshaft position detection signal.

Further, various sensors (intake pressure sensor, cooling water temperature sensor, throttle sensor, etc .: none of them are shown) for detecting the operating state of the engine are connected to the engine control device 14. The engine control device 14 performs fuel injection control for driving the intake valve 4 and the exhaust valve 6 and ignition control for the spark plug 7 according to the engine operating state detected by these various sensors.

The engine control device 14 and the electric cam phase control device 13 continuously control the cam phase θc using the electric VCT system S to continuously control the intake valve 4 for supplying air to the cylinder of the engine block 2 and the exhaust gas. The opening / closing timing of the exhaust valve 6 to be discharged is optimized.

The engine control device 14 determines the target cam of the electric actuator 15 based on the actual cam phase θc of the electric actuator 15 input from the electric cam phase control device 13 and the phase of the crankshaft 8 that can be detected by the crank angle sensor 10. The phase θcref is calculated and output to the electric cam phase control device 13. The electric cam phase control device 13 controls the valve timing based on the input target cam phase θcref, and controls the actual valve opening / closing timings of the intake valve 4 and the exhaust valve 6 so as to match the target valve opening / closing timing.

When transmitting the cam control signal to the electric cam phase control device 13, the engine control device 14 transmits the information of the target cam phase θcref using the PWM signal for the command. The electric cam phase control device 13 controls the cam phase θc based on the target cam phase θcref, and transmits the actually measured information of the actual cam phase θc to the engine control device 14. The electric cam phase control device 13 also transmits the information of the actual cam phase θc to the engine control device 14 by using the PWM signal.

As shown in FIG. 2, the duty ratio range of the PWM signal that can be instructed by the engine control device 14 to the electric cam phase control device 13 is assigned in advance. When the duty ratio of the PWM signal is in the range D from the lower limit command duty ratio HL (for example, 10%) to the upper limit command duty ratio HH (for example, 90%), the engine control device 14 is used for commanding the duty ratio within this range D. By transmitting the PWM signal to the electric cam phase control device 13, the target cam phase θcref is commanded as the cam control signal.

Further, the duty ratio of the PWM signal is 0% to the lower limit command duty ratio HL is assigned in advance as the correction instruction range of the latest retardation range DL. The latest retard range DL is a duty ratio range for a correction command, and the engine control device 14 corrects by transmitting a cam control signal of the duty ratio within the latest retard range DL to the electric cam phase control device 13. Can be ordered.

Further, the duty ratio of the PWM signal is the upper limit command duty ratio HH to 100%, which is assigned in advance as the correction instruction range of the maximum advance angle range DH. The maximum advance angle range DH is also a range indicating the duty ratio for the correction command, and the engine control device 14 transmits a cam control signal of the duty ratio within the maximum advance angle range DH to the electric cam phase control device 13. The correction command can be given.

Further, the range of the duty ratio of the PWM signal when the electric cam phase control device 13 transmits the information of the actual cam phase θc to the engine control device 14 is also assigned in advance. These duty ratios are also in the range D from the lower limit command duty ratio HL to the upper limit command duty ratio HH, and the electric cam phase control device 13 transmits a PWM signal of the duty ratio within this range D to the engine control device 14. Information on the actual cam phase θc can be transmitted with.

Further, similarly to the above, the range in which the duty ratio of the PWM signal is 0% to the lower limit command duty ratio HL is assigned in advance as the correction instruction range of the latest retard angle range DL, and the duty ratio of the PWM signal is the upper limit command duty ratio. The range of 100% from HH is pre-allocated as the correction instruction range of the maximum advance angle range DH. The electric cam phase control device 13 can give a correction command by transmitting a control signal of a duty ratio within the latest retard range DL and the maximum advance range DH to the engine control device 14.

In the present embodiment, the duty ratio latest retard range DL and maximum advance range DH are a PWM signal for commanding a cam control signal transmitted by the engine control device 14 and an actual cam transmitted by the electric cam phase control device 13. The form in which the PWM signal indicating the phase θc information is set in the same range will be described, but the present invention is not limited to this, and the duty ratios may be set in different duty ratio ranges.

Hereinafter, the details of the control from before the engine is started to the normal engine control will be described in chronological order.
When the ignition switch is turned on, battery power is supplied to the engine control device 14 and the electric cam phase control device 13. Then, the engine control device 14 executes the pre-start process shown in FIG. 3, and the electric cam phase control device 13 executes the pre-start process shown in FIG.

First, the engine control device 14 on the command transmission side transmits the PWM signal set to the duty ratio within the latest retard range DL in S11 of FIG. 3 to the electric cam phase control device 13 as a cam control signal. The engine control device 14 defines the duty ratio (hereinafter, referred to as the latest retard angle duty ratio) of the PWM signal transmitted in the first pulse PT1 in advance with the electric cam phase control device 13.

As shown in FIG. 5, the engine control device 14 sets the rise / fall timings so as to satisfy the above-mentioned regulation of the latest retard angle duty ratio by counting the internal clock from the output start timing of the PWM signal. The first pulse PT1 is transmitted. As a result, the engine control device 14 transmits the latest retard angle command for moving the cam phase θc to the latest retard angle to the electric cam phase control device 13 before starting the starter of the engine body 1.

On the other hand, when the electric cam phase control device 13 on the receiving side receives and inputs the cam control signal in S31 of FIG. 4, the duty ratio is measured by measuring the periodic width and pulse width TRx of the PWM signal in S32.

Specifically, the electric cam phase control device 13 counts the internal clock in the control device 13 by a counter, so that the time between adjacent falling timings of the PWM signals of the counter is the period of the first 1 pulse PR1. In addition to measuring as the width, the time between the rising timing and the falling timing is measured as the pulse width TRx. As a result, the duty ratio can be measured using the period of the PWM signal and the pulse width TRx.

Although schematically shown in FIG. 5, the deviation of the count number due to the transmission / reception frequency deviation of the internal clocks configured in the control devices 13 and 14 and the deviation of the pulse widths TTx and TRx due to the change in the component characteristics are observed. May occur. Therefore, the period and duty ratio of the PWM signal measured by the counters of the control devices 14 and 13 on the transmitting side and the cycle and duty ratio of the PWM signal measured by the counters of the control devices 13 and 14 on the receiving side may be different. is there. Therefore, as described in the "Problems to be Solved by the Invention" column, the PWM signal is input between the PWM signal input / output by the engine control device 14 and the PWM signal input / output by the electric cam phase control device 13. It may cause a recognition error of the period and duty ratio.

Therefore, in the present embodiment, when the duty ratio of the 1-pulse PR1 of the received and input PWM signal is the latest retard range DL or the maximum advance range DH, the electric cam phase control device 13 on the receiving side has S33 in FIG. Alternatively, if YES in S34, it is determined that the correction instruction range is within the predetermined range, the correction amount of the pulse width, the period, and the duty ratio is calculated in S35, and the correction amount is stored in the storage unit 13b in S36. At this time, the electric cam phase control device 13 calculates the difference between the accurate pulse width, period, and duty ratio stored in its own non-volatile storage unit 13d and the predetermined reference values, and stores the difference in the storage unit 13b as a correction amount. Let me.

At this time, it is advisable to set the cycle correction amount α as the accurate cycle count number (predetermined reference value) on the transmitting side / the cycle count number at the time of reception, and calculate the difference from the cycle predetermined reference value (accurate cycle count number). .. Further, it is preferable to set the pulse width correction amount β as the accurate pulse width count number on the transmitting side / the pulse width count number on the receiving side, and calculate the difference from the predetermined reference value (accurate pulse width count number) of the pulse width. As a result, the electric cam phase control device 13 can calculate the duty ratio correction amount from these period correction amounts α and pulse width correction amount β.

The electric cam phase control device 13 can calculate the correction amount when the first 1 pulse PR1 of the PWM signal is received and input, and in S39 of FIG. 4, the pulse width, period, and duty ratio of the PWM signal are corrected based on this correction amount. it can. As a result, the electric cam phase control device 13 can accurately calculate the duty ratio of the latest retard angle command, and can control the cam phase θc based on the latest retardation command in S40.

The electric cam phase control device 13 detects the actual cam phase θc when the cam phase θc is controlled based on the latest retardation command, and transmits the information of the actual cam phase θc detected in S41 to the engine control device 14. After that, the electric cam phase control device 13 waits for a cam control signal from the engine control device 14.

When the duty ratio of 1 pulse PR1 of the received and input PWM signal is not in the latest retard range DL or the most advanced range DH, the electric cam phase control device 13 determines NO in S33 and S34, and determines the predetermined value. It is judged that it is not within the correction instruction range of. In this case, the electric cam phase control device 13 determines in S37 whether or not the correction amount has already been set in the storage unit 13b.

If the correction amount has already been set in the storage unit 13b, the electric cam phase control device 13 corrects the PWM signal cycle, pulse width, and duty ratio in S39 to S41, and then controls the cam phase θc, and actually controls the cam phase θc. Information on the cam phase θc is transmitted to the engine control device 14 by a PWM signal.

However, if the correction amount is not set in the storage unit 13b, the electric cam phase control device 13 cannot correct the duty ratio based on the correction amount. Therefore, the diagnostic information indicating an abnormality is transmitted to the engine control device 14 and in S38. Stops pre-start processing and performs protective operation (fail safe). The engine control device 14 executes a fail-safe process as necessary based on the received diagnostic information. After that, the electric cam phase control device 13 waits for a cam control signal from the engine control device 14.

When the electric cam phase control device 13 normally transmits the information of the actual cam phase θc to the engine control device 14 by the PWM signal in S41 of FIG. 4, the engine control device 14 normally transmits the actual cam phase by the PWM signal in S12 of FIG. Receives θc information.

If the electric cam phase control device 13 normally controls the cam phase θc based on the engine control device 14's latest retardation command, the cam phase θc is controlled to the slowest angle, and the actual cam phase θc is the slowest angle. Reach the range DL. When the engine control device 14 recognizes that the actual cam phase θc has reached the maximum retardation range DL, it determines YES in S14.

The electric cam phase control device 13 moves the cam phase θc to a position where it is easy to restart (for example, the latest retardation angle) before starting the starter, but the engine control device 14 is an electric cam phase control device. During the control to the target cam phase θcref by 13, the first target cam phase θcref may be calculated by using another sensor signal in parallel with this process. In this case, the engine control device 14 can immediately control the cam phase θc by outputting the target cam phase θcref corrected at the time of starting the engine to the electric cam phase control device 13 as a cam control signal.

The engine control device 14 calculates the correction amount of the period, pulse width, and duty ratio of the received PWM signal in S15, and stores the correction amount in its own storage unit 14b in S16. At this time, the engine control device 14 calculates the difference between the accurate period, the pulse width, and the duty ratio stored in the storage unit 14b and the predetermined reference value, and stores the correction amount in the storage unit 14b. Then, the engine control device 14 corrects the actual cam phase θc by using the correction amount stored in the storage unit 14b in S21.

Therefore, the engine control device 14 can calculate the correction amount when the first 1-pulse PR1 is received and input, and can correct the period, pulse width, and duty ratio of the PWM signal based on this correction amount. As a result, in S21 of FIG. The actual cam phase θc can be corrected. After this, the engine control device 14 starts the starter.

The engine control device 14 determines NO when the duty ratio of the 1-pulse PR1 of the PWM signal received and input in S14 is not within the latest retard range DL. The engine control device 14 determines in S17 whether or not the correction amount has already been set in the storage unit 14b.

If the correction amount has already been set in the storage unit 14b, the engine control device 14 corrects the actual cam phase θc using the correction amount in S21 and S22 and starts the starter. However, if the correction amount is not set in the storage unit 14b, the engine control device 14 cannot correct the duty ratio based on the correction amount. Therefore, the engine control device 14 determines whether or not a predetermined time has elapsed from the start timing at which the latest retard angle command is output in S18, and if the predetermined time has elapsed, the engine control device 14 stops the pre-start processing and performs a protective operation. (Fail safe) and stop the operation of the engine in S20. In this case, it is possible to notify the user to that effect by issuing an abnormality warning to the outside.

Hereinafter, the normal processing executed by the engine control device 14 and the electric cam phase control device 13 following the pre-start processing will be described with reference to FIGS. 6 and 7. Note that, in FIGS. 6 and 7, the same step numbers are assigned to the steps for executing the same contents as the pre-start processing shown in FIGS. 3 and 4.

After starting the starter in S22 of FIG. 3, the engine control device 14 executes the normal process shown in FIG. Normally, the engine control device 14 calculates the target cam phase θcref based on the sensor information of various sensors, and transmits the cam control signal by the PWM signal of the duty ratio corresponding to the target cam phase θcref in S11a of FIG. The engine control device 14 sets the duty ratio in the range D other than the latest retard range DL or the most advanced range DH, and transmits the PWM signal.

Normally, when the electric cam phase control device 13 receives the above-mentioned target cam phase θcref from the engine control device 14, it determines NO in S33 and S34 of FIG. 7, and is learned before this timing and stored in the storage unit 13b. The period, pulse width, and duty ratio of the PWM signal are corrected using the corrected amount. The electric cam phase control device 13 corrects the target cam phase θcref by correcting the duty ratio obtained by the measurement, and controls the cam phase θc with the target cam phase θcref as the target in S40.

Further, even in the normal state, the engine control device 14 may output the latest retard angle command or the most advanced angle command according to the duty ratio of the most retarded angle range DL or the most advanced angle range DH. In this case, when the electric cam phase control device 13 inputs the latest retard angle command or the most advanced angle command, it determines YES in S33 or S34, calculates the correction amount in S35, and stores the correction amount of the duty ratio in S36. Update storage is performed in unit 13b. As a result, the electric cam phase control device 13 can update the correction amount without executing the interrupt process based on the occurrence of the correction event, and can continuously execute the electric cam phase control thereafter.

After that, the electric cam phase control device 13 corrects the target cam phase θcref by correcting the period, pulse width, and duty ratio of the PWM signal in S39 of FIG. 7, and based on the corrected target cam phase θcref in S40. The cam phase θc is controlled. Then, the electric cam phase control device 13 detects the actual cam phase θc and transmits the information of the actual cam phase θc to the engine control device 14 in response in S41.

When the engine control device 14 receives the PWM signal from the electric cam phase control device 13 in S12 and S13 of FIG. 6 as a result of transmitting the target cam phase θcref to the electric cam phase control device 13, the engine control device 14 measures the duty ratio of the PWM signal. By doing so, the detection result of the actual cam phase θc can be obtained.

After that, the engine control device 14 corrects the actual cam phase θc by using the correction amount stored in the storage unit 14b in S23. At this time, the engine control device 14 continues to control the actual cam phase θc after recognizing the position of the current actual cam phase θc using the corrected actual cam phase θc. The engine control device 14 determines whether or not the state in which the difference between the target cam phase θcref commanded to the electric cam phase control device 13 in S24 and the actual cam phase θc is larger than the predetermined difference continues for a certain period of time.

If the engine control device 14 and the electric cam phase control device 13 can continue normal cooperative control, the actual cam phase θc follows the target cam phase θcref. Therefore, even if there is a momentary state in which the difference between the target cam phase θcref and the actual cam phase θc is larger than the predetermined difference, the time for which this state continues is short. Therefore, when the engine control device 14 determines that the actual cam phase θc follows the target cam phase θcref, it determines NO in S24 and starts calculating the next target cam phase θcref. That is, the engine control device 14 recalculates the target cam phase θcref, returns to S11a, and repeats the normal process.

Even if the duty ratio and the actual cam phase θc are corrected based on the correction amount, the engine control device 14 is normal as long as the difference between the target cam phase θcref and the actual cam phase θc is larger than the predetermined difference for a certain period of time. Judged as out of control. As a result, the engine control device 14 can determine whether or not there is an abnormality during control of the actual cam phase θc based on the corrected actual cam phase θc and the target cam phase θcref of the output cam control signal. The engine control device 14 can accurately determine the abnormality with the minimum correction delay by determining the abnormality based on the actual cam phase θc corrected by the correction value. When it is determined that normal control is impossible, the engine control device 14 starts a protective operation (fail-safe process) by executing an abnormal measure of cam phase control in S25.

The engine control device 14 determines in S14 and S14a whether or not the duty ratio is in the latest retard range DL or the most advanced range DH even during normal control, and satisfies either of these determination conditions. If this is the case, it may be determined that the correction amount is within the predetermined correction instruction range, the correction amount may be calculated based on the difference from the predetermined reference value in S15 and S16, and the correction amount may be overwritten and updated in the storage unit 14b.

Next, the control blocks of the engine control device 14 and the electric cam phase control device 13 will be described in comparison with the control blocks of the comparative example.
FIG. 8 shows a block diagram of the engine control device 14 and the electric cam phase control device 13 of the present embodiment. As shown in FIG. 8, the engine control device 14 transmits information on the target cam phase θcref to the electric cam phase control device 13 through the signal line 16. The electric cam phase control device 13 controls the cam phase θc using the control blocks B1 to B13 of the illustrated embodiment, and transmits the detected actual cam phase θc to the engine control device 14 through the signal line 16.

When the target cam phase θcref is input through the signal line 16, the electric cam phase control device 13 calculates the difference between the target cam phase θcref and the actual cam phase θc by the subtractor B1 and outputs the difference to the phase controller B2. The phase controller B2 controls the phase of the calculation result of the subtractor B1 and outputs the target cam speed ωcref to the gear ratio adjusting unit B3.

The gear ratio adjusting unit B3 divides the target cam speed ωcref by the gear ratio ε and outputs it to the adder B4. The adder B4 adds the speed output by the gear ratio adjusting unit B3 and the sprocket speed ωs and outputs the target speed ωmref to the subtractor B5. The subtractor B5 calculates the difference between the target speed ωmref and the output speed ωm in consideration of the error / delay element Ei (s), and outputs the difference to the speed controller B6. Here, the error / delay element i is a subscript indicating that each element is independent. The speed controller B6 calculates the speed based on the difference calculated by the subtractor B5, and controls the rotation speed of the plant B7 such as the electric actuator 15.

The subtractor B8 calculates the difference between the output Tm of the plant B7 and the target output Tl and outputs the difference to the speed calculator B9. The speed calculator B9 calculates the output speed ωm by performing an integral calculation based on the moment of inertia Jm, and outputs the output speed ωm to the subtractor B10. The subtractor B10 outputs the result of subtracting the sprocket speed ωs from the output speed ωm to the gear ratio adjusting unit B11. The gear ratio adjusting unit B11 multiplies the output of the subtractor B10 by the gear ratio ε, and the integrator B12 integrates the output of the gear ratio adjusting unit B11 and outputs it to the actual cam phase calculation unit B13.

The actual cam phase calculation unit B13 calculates the actual cam phase θc based on the cam sensor signal of the cam angle sensor 18 or 19 and the integration result of the integrator B12, feeds back the actual cam phase θc to the subtractor B1, and signals the actual cam phase θc. The actual cam phase θc is output to the engine control device 14 through the wire 16.

Note that the signal line 16 and the like are shown in FIG. 8 because an error / delay element Ei (s) is generated. As a result, the engine control device 14 can monitor the difference from the target cam phase θcref by inputting the actual cam phase θc through the signal line 16.

When the engine control device 14 detects the actual cam phase θc in such a control system, an error / delay element Ei (s) due to the signal line 16 is generated from the engine control device 14 to the electric cam phase control device 13. The error / delay element Ei (s) also occurs from the electric cam phase control device 13 to the engine control device 14. In this case, the engine control device 14 can quickly detect the accurate actual cam phase θc by correcting the error / delay element Ei (s) by the signal line 16. Further, the engine control device 14 may have a margin in the detection time in consideration of, for example, that the actual cam phase θc shifts based on the error / delay element Ei (s).

On the other hand, FIG. 9 shows a comparative example. FIG. 9 shows the components corresponding to the engine control device 14, the signal line 16, and the electric cam phase control device 13 described above, so that the engine control device 14, the signal line 16, and the electric cam phase control device are shown in FIG. It is shown by adding a subscript z to the code of 13.

When the functions of the control blocks B1 to B12 are separated and configured as a whole between the engine control device 14z and the electric cam phase control device 13z, the control blocks B6 to B9 of the electric cam phase control device 13z can be simplified. However, if the influence of the error / delay element Ei (s) due to the signal line 16z occurs to a non-negligible degree, advanced signal recording, signal transmission functions, and control functions in consideration of these error / delay elements Ei (s) are required. Therefore, a high degree of circuit reliability is required. Further, on the side of the electric cam phase control device 13z, it is necessary to separately record the diagnosis or transmit the diagnosis information to the engine control device 14z for security measures.

According to the control system shown in the present embodiment, it is not necessary to take measures as shown in the comparative example, and the engine control device 14 corrects the error / delay element Ei (s) by the signal line 16 in FIG. The real cam phase θc can be detected quickly.

<Summary of this embodiment>
Conventionally, there is a method in which an interrupt by a reference signal is periodically generated, or a reference signal is transmitted prior to an instruction signal and corrected according to the reference signal. However, in this conventional method, the interrupt processing is added and the cycle of the control signal becomes long. The electric cam phase control device 13 according to the present embodiment can be corrected by using a correction amount without using interrupt processing, and is a target while avoiding interrupt treatment by a reference signal and lengthening of a control cycle by an unnecessary reference signal. The transmission error of the cam phase θcref can be corrected.

The electric cam phase control device 13 corrects the input command PWM signal based on the calculated correction amount, and controls the cam phase θc using the correction result, so that the cam phase θc is adjusted to the cam control signal. It can be controlled accurately.

Further, when the electric cam phase control device 13 receives the command PWM signal as the information of the target cam phase θcref from the engine control device 14, the electric cam phase control device 13 measures the pulse width, period, and duty ratio of the PWM signal and measures the maximum advance angle range DH or The correction amount is calculated on condition that the maximum retardation range DL is recognized. Since the electric cam phase control device 13 is instructed within a predetermined correction instruction range, it can be easily recognized that it is a correction command.

When the engine control device 14 receives the PWM signal as the information of the actual cam phase θc from the electric cam phase control device 13, the maximum advance angle range DH or the latest retard angle range from the pulse width, period, and duty ratio of the PWM signal. The correction amount is calculated on the condition that it is recognized as DL. Since the engine control device 14 is instructed within a predetermined correction instruction range, it can be easily recognized that the engine control device 14 is a correction instruction. Then, the engine control device 14 can accurately acquire the actual cam phase θc by correcting the PWM signal indicating the input information of the actual cam phase θc based on the calculated correction amount.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and for example, the following modifications or extensions are possible.
The electric cam phase control device 13 and the engine control device 14 set the correction amount as a predetermined correction instruction range when the duty ratio of the PWM signal received from the other side is in the latest retard range DL or the most advanced range DH. However, the calculation is not limited to the latest retard range DL and the most advanced range DH, and the correction instruction range may be set in advance in the intermediate range D.

The electric cam phase control device 13 and the engine control device 14 have shown a mode in which correction is performed based on the 1-pulse PR1 of the PWM signal that is first transmitted and received from each other, but the present invention is not limited to this, and for example, the second and subsequent times are performed. The correction may be performed based on one predetermined pulse of the PWM signal, or the correction amount may be averaged and calculated based on a plurality of pulses.

The electric cam phase control device 13 and the engine control device 14 have shown a mode in which the correction amount is calculated before the starter is started after the power is turned on, or the correction amount is calculated during normal operation, but the operation after the next power on The correction amount may be stored in the non-volatile storage units 13d and 14d, respectively.

For example, at the timing immediately before the power supply to the electric cam phase control device 13 and the engine control device 14 is stopped, such as immediately before the engine is stopped when the ignition switch is turned off, the electric cam phase control device 13 and the engine control device 14 The CPUs 13a and 14a may store the correction amount in the non-volatile storage units 13d and 14d, respectively. As a result, the electric cam phase control device 13 and the engine control device 14 can read the correction amount from the non-volatile storage units 13d and 14d at the next engine start, respectively, and correct the PWM signal cycle, pulse width, and duty ratio.

An embodiment in which a part of the above-described embodiment is omitted as long as the problem can be solved can also be regarded as an embodiment. In addition, any conceivable embodiment can be regarded as an embodiment without departing from the essence of the invention specified by the wording described in the claims.

Although the present disclosure has been described in accordance with the embodiments described above, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure also includes various modifications and modifications within an equal range. In addition, various combinations and forms, as well as other combinations and forms, including one element, more, or less, are also within the scope of the present disclosure.

In the drawing, 13 is an electric cam phase control device (measurement unit, correction amount calculation unit, correction unit, control unit), 13d is a non-volatile storage unit, and 14 is an engine control device (measurement unit, correction amount calculation unit, correction unit). Abnormality determination unit), 14d indicates a non-volatile storage unit.

Claims (8)

An electric cam phase control device (13) that controls the cam phase of the electric camshaft by inputting a cam control signal of the electric camshaft from the engine control device.
When a PWM signal for a command corresponding to the cam control signal of the electric camshaft is input from the engine control device, a measurement unit (S32) that measures the duty ratio of the PWM signal and
When the duty ratio of the PWM signal is within a predetermined correction instruction range, the correction amount is based on the difference between the duty ratio of the PWM signal and the predetermined reference value of the duty ratio set in the predetermined correction instruction range. The correction amount calculation unit (S35) that calculates
A correction unit (S39) that corrects the PWM signal input based on the correction amount calculated by the correction amount calculation unit, and
A control unit (S40) that controls the cam phase using the correction result of the correction unit, and
An electric cam phase control device comprising. In the correction amount calculation unit, as the predetermined correction instruction range based on the duty ratio, the cam control signal corresponding to the duty ratio has a predetermined maximum retardation range (DL) or maximum advance angle range (DH). ), The electric cam phase control device according to claim 1, wherein the correction amount is calculated. The correction amount calculation unit calculates the correction amount based on one pulse of the PWM signal for the command whose duty ratio is measured by the measurement unit, and the correction unit calculates the correction amount of the PWM signal of the one pulse. The electric cam phase control device according to claim 1 or 2, which corrects the duty ratio. The correction amount calculation unit calculates the correction amount from the first pulse of the PWM signal input from the engine control device, and the correction unit calculates the duty ratio of the PWM signal of the first pulse. The electric cam phase control device according to any one of claims 1 to 3 to be corrected. A non-volatile storage unit (13d) for non-volatilely storing the information of the correction amount calculated by the correction amount calculation unit is further provided.
The electric cam phase control device according to any one of claims 1 to 4, wherein the correction unit corrects the PWM signal based on the correction amount stored in the non-volatile storage unit. An engine control device (14) that causes the electric cam phase control device to control the cam phase of the electric camshaft by transmitting a cam control signal of the electric camshaft to the electric cam phase control device.
An engine control device that uses a PWM signal as the cam control signal when transmitting the cam control signal of the electric camshaft to the electric cam phase control device according to any one of claims 1 to 5. After transmitting the cam control signal to the electric cam phase control device, the actual cam phase when the cam phase is controlled by the electric cam phase control device is received from the electric cam phase control device by the PWM signal, and the received said. An engine control device (14) that acquires the actual cam phase based on a PWM signal.
When the PWM signal is input from the electric cam phase control device, the measuring unit (S13) that measures the duty ratio of the PWM signal corresponding to the actual cam phase and
When the duty ratio of the PWM signal is within a predetermined correction instruction range, correction is made based on the difference between the duty ratio of the PWM signal and the predetermined reference value of the duty ratio set in the predetermined correction instruction range. The correction amount calculation unit (S15) that calculates the amount, and
An engine control device including a correction unit (S16) for correcting the actual cam phase acquired from the PWM signal based on the correction amount calculated by the correction amount calculation unit. An abnormality presence / absence determination unit (S18) for determining the presence / absence of an abnormality during control of the cam phase by the electric cam phase control device based on the actual cam phase corrected by the correction unit and the transmitted cam control signal. The engine control device according to claim 7.

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