JP2014105625A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine control device capable of allowing a control device abnormal in cylinder determination, to execute cylinder determination while suppressing increase of communication load and processing load of a specific control device.SOLUTION: A first control device acquires an abnormal time data composed of a crank position and an engine speed stored in control processing executed at a timing of a crank angle signal just before (S442), in a case of abnormal cylinder determination of a second control device (S440:Yes), and determines whether a transmission timing of the abnormal time data or not (S444). The abnormal time data is transmitted at a timing of every 30°CA, for example, 0°CA, 30°CA and 60°CA. In the abnormal time data transmission timing (S444:Yes), the first control device transmits the abnormal time data to the second control device (S446). The second control device can execute cylinder determination on the basis of the abnormal time data received from the first control device, even when it is abnormal in cylinder determination.

Description

  The present invention relates to an engine control device including a first control device and a second control device that are connected so as to be communicable with each other and perform cylinder discrimination with each other.

  Conventionally, a technique in which a plurality of control devices are communicably connected to each other and the control devices share information with a common signal line is known (for example, see Patent Document 1). In Patent Document 1, in a predetermined control device, predetermined information among a plurality of pieces of information is configured to be input through both a common signal line and a dedicated signal line, and predetermined information is received from one of the common signal line and the dedicated signal line. Is not input, predetermined information is input from the other of the common signal line and the dedicated signal line.

Japanese Patent Publication No. 7-105801

  For example, when the technology of Patent Document 1 is applied to the case where each control device performs cylinder discrimination by sharing sensor signals of sensors that respectively detect the angular positions of the crankshaft and the camshaft, the predetermined control device uses a common signal line or Even if an abnormality in which a sensor signal cannot be input from one of the dedicated signal lines occurs, the cylinder discrimination can be performed normally by inputting the sensor signal from the other of the common signal line or the dedicated signal line.

However, since it is necessary for a specific control device to always output a sensor signal to the common signal line, the communication load of the common signal line and the processing load of the control device that outputs the sensor signal increase.
The present invention has been made to solve the above problem, and provides an engine control device that can suppress an increase in communication load and processing load of a specific control device, and can perform cylinder discrimination by a cylinder discrimination abnormality control device. The purpose is to do.

  According to the engine control device of the present invention, the first control device and the second control device are communicably connected to each other, and the second control device executes engine control according to a control command transmitted from the first control device. The first control device and the second control device perform cylinder discrimination by inputting sensor signals from the crank angle sensor and the cam angle sensor, respectively.

Then, when the first determination means of the first control device determines that the second control device is abnormal in cylinder discrimination, the first control device transmits the cylinder discrimination information generated by the first discrimination means to the second control device. .
According to this configuration, the first control device transmits the cylinder discrimination information to the second control device when the second control device is abnormal in cylinder discrimination, and the second control device performs the cylinder discrimination normally. Does not transmit cylinder discrimination information to the second controller. Therefore, an increase in the communication load and the processing load of the first control device can be suppressed, and the second control device can execute cylinder discrimination even in the case of cylinder discrimination abnormality.

The block diagram which shows the engine control system by this embodiment. The time chart which shows the cylinder discrimination | determination based on a crank angle signal and a cam angle signal. The flowchart which shows the control processing of ECU. The flowchart which shows the abnormal transmission process of EDU. The flowchart which shows the abnormality reception process of ECU. The flowchart which shows the data transmission process at the time of abnormality of ECU. The flowchart which shows the cylinder discrimination | determination process at the time of abnormality of EDU. The time chart which shows the process at the time of cylinder discrimination | determination abnormality.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Engine control system 10)
FIG. 1 shows an engine control system 10 of the present embodiment. The engine control system 10 controls, for example, the operating state of a 6-cylinder diesel engine for automobiles (hereinafter also simply referred to as “engine”). The engine control system 10 includes a fuel supply pump 14, a common rail 20, a fuel injection valve 30, an electronic control unit (ECU) 40, and an electronic drive unit (EDU) 42. The ECU 40 and the EDU 42 are communicably connected by a CAN 200 and constitute an engine control device.

  The fuel supply pump 14 incorporates a feed pump that pumps fuel from the fuel tank 12. The fuel supply pump 14 is a known pump that pressurizes the fuel sucked into the pressurizing chamber from the feed pump when the plunger reciprocates as the cam of the camshaft rotates. The camshaft rotates once while the crankshaft rotates twice.

  The metering valve 16 serving as a metering actuator is installed on the suction side of the fuel supply pump 14 and controls the amount of fuel sucked by each plunger of the fuel supply pump 14 in the suction stroke by current control. . By adjusting the fuel intake amount, the discharge amount of the fuel supply pump 14 is adjusted. A configuration may be adopted in which a metering valve is provided on the discharge side of the fuel supply pump to meter the discharge amount.

  The common rail 20 is a hollow member that accumulates fuel pumped from the fuel supply pump 14. The common rail 20 is provided with a pressure sensor 22 that detects an internal fuel pressure (rail pressure) and a pressure reducing valve 24 that reduces the rail pressure by overflowing the internal fuel to the fuel tank 12 side. A pressure limiter may be installed instead of the pressure reducing valve 24, and when the rail pressure exceeds a predetermined pressure, the fuel in the common rail 20 may be discharged to the fuel tank 12 side to prevent the rail pressure from exceeding the predetermined pressure.

  The fuel injection valve 30 is installed in each cylinder of the engine 2 and injects fuel accumulated in the common rail 20 into the cylinder. The fuel injection valve 30 is, for example, a known electromagnetic valve that controls the lift of the nozzle needle that opens and closes the nozzle hole with the pressure in the control chamber.

  The ECU 40 and the EDU 42 are mainly configured by a microcomputer centering on a CPU, RAM, ROM, flash memory, and the like. The EDU 42 further includes a drive circuit for driving the metering valve 16, the pressure reducing valve 24, and the fuel injection valve 30.

  ECU40 and EDU42 perform various control of the engine control system 10 based on the sensor signal of various sensors, when CPU runs the control program memorize | stored in ROM or flash memory.

  The engine control system 10 includes a pressure sensor 22, an accelerator opening sensor 50, a crank angle sensor 52, a cam angle sensor 54, a temperature sensor that detects the temperature of the cooling water (water temperature), the temperature of the intake air (intake air temperature), and the like. Is installed.

  The ECU 40 and the EDU 42 detect the angle position of the crankshaft based on the crank angle signal output from the crank angle sensor 52 and detect the time required for the crankshaft to make one rotation (360 °) based on the crank angle signal. As a result, the engine speed [rpm] per minute is calculated. Further, the ECU 40 and the EDU 42 detect the angular position of the camshaft based on the cam angle signal output from the cam angle sensor 54. Then, the ECU 40 and the EDU 42 perform cylinder discrimination based on the input crank angle signal and cam angle signal.

  The ECU 40 calculates a rail pressure target pressure (also referred to as a target rail pressure) from a map or the like based on the accelerator opening and the engine speed. Further, the ECU 40 calculates the injection amount of the fuel injection valve 30 from a map or the like based on the accelerator opening and the engine speed, and calculates the injection timing from the map or the like based on the calculated injection amount and the engine speed. . Further, the ECU 40 determines a cylinder to inject fuel next from the cylinder discrimination result.

  The ECU 40 transmits control parameters for controlling the engine 2 such as the target rail pressure, the injection cylinder, the injection amount of the fuel injection valve 30, and the injection timing to the EDU 42 via the CAN 200 as a control command.

  The EDU 42 controls the drive current for the metering valve 16 based on the differential pressure between the target rail pressure transmitted from the ECU 40 and the actual rail pressure detected by the pressure sensor 22, and the injection cylinder and the injection amount transmitted from the ECU 40. The drive current for the fuel injection valve 30 is controlled based on the injection timing. Further, the EDU 42 drives opening / closing of the pressure reducing valve 24 according to a command from the ECU 40.

(Cylinder discrimination)
The crank angle signal is generated when the crank angle sensor 52 detects teeth formed at intervals of 6 ° on the outer periphery of the crank rotor fixed to the crankshaft as the crankshaft rotates. A missing tooth portion with missing teeth is formed in the middle of the tooth row of the crank rotor. The interval between teeth formed on the outer periphery of the crank rotor is not limited to 6 °, and may be smaller or larger than 6 °.

  The cam angle signal is generated when the cam angle sensor 54 detects teeth formed at six positions on the outer periphery of the cam rotor fixed to the camshaft at intervals of 60 ° as the camshaft rotates. Of the six locations, two teeth are formed in one location, and one tooth is formed in the other five locations. Therefore, as shown in FIG. 2, after one cam angle signal is generated five times every 120 ° CA (crank angle), two cam angle signals are continuously generated at the next 120 ° CA interval.

  The teeth formed on the cam rotor are formed, for example, at positions that reach the compression top dead center of any cylinder after a predetermined crank angle after the cam angle sensor 54 detects and outputs a cam angle signal.

  When starting the engine, the ECU 40 and the EDU 42 perform cylinder discrimination based on a combination of the missing tooth portion of the crank angle signal and one or two output cam angle signals, and determine which cylinder the next compression TDC corresponds to. Determine.

  The ECU 40 and the EDU 42 count up the crank counter each time a crank angle signal is generated after performing cylinder discrimination at the start. For example, the crank counter is cleared to 0 every 720 ° CA at a reference position where two cam angle signals are generated.

  The value of the crank counter represents the rotational position of the crankshaft of each cylinder (hereinafter also referred to as “crank position”) in one combustion cycle (720 ° CA) consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. Therefore, cylinder discrimination can be performed. The value of the crank counter and the crank position are cylinder discrimination information generated to perform cylinder discrimination.

(Control processing of ECU 40)
Next, control processing in which the ECU 40 transmits control parameters to the EDU 42 will be described based on the flowchart of FIG. In the flowcharts of FIGS. 3 to 7, “S” represents a step. The flowchart of FIG. 3 is executed for each crank angle signal generated at intervals of 6 ° CA.

  The ECU 40 performs cylinder discrimination based on the crank angle signal and the cam angle signal (S400), and obtains abnormal data and accelerator opening (S402). The abnormal data consists of the crank position and the engine speed. The ECU 40 stores the acquired abnormality data in the RAM.

  If the crank position is an injection command set position for instructing the fuel injection valve 30 of each cylinder to inject (S404: Yes), the ECU 40 determines whether the common rail 20 of the common rail 20 from the map or the like based on the accelerator opening and the engine speed. The target rail pressure, the injection amount of the fuel injection valve 30 and the injection timing are calculated (S406), and the next injection cylinder is determined from the crank position (S408). The injection command set position is set, for example, 60 ° CA before the TDC of each cylinder.

Then, the ECU 40 transmits the target rail pressure, the injection cylinder, the injection timing, and the injection amount to the EDU 42 via the CAN 200 (S410).
(Abnormal transmission processing)
The abnormal transmission process of FIG. 4 is executed by the EDU 42 at every predetermined time period or every crank angle signal.

  Based on the result of the cylinder discrimination, the EDU 42 determines whether or not the own apparatus has a cylinder discrimination abnormality (S420). In the cylinder discrimination abnormality judgment, the crank angle signal or the cam angle signal is set for a predetermined time because the number of counts is larger than that of the crank counter counted at 720 ° CA due to noise or the like, or due to disconnection, short circuit to the power source side, etc. This is done by determining whether there is no input in between.

  In the case of cylinder discrimination abnormality (S420: Yes), for example, the EDU 42 transmits to the ECU 40 that the EDU 42 is cylinder discrimination abnormality by using a predetermined bit of a data field in a data frame in CAN communication as a flag (S422). The EDU 42 stores in the RAM with a flag or the like whether or not the device itself is in cylinder discrimination abnormality.

(Abnormal reception processing)
The abnormality reception process of FIG. 5 is executed when the ECU 40 receives CAN communication from the EDU 42.

  When the CAN communication is received from the EDU 42, the ECU 40 determines whether or not the EDU 42 has a cylinder discrimination abnormality from a predetermined bit of the data field in the received data frame (S430).

  When the EDU 42 has a cylinder discrimination abnormality (S430: Yes), the ECU 40 turns on an abnormality flag indicating whether or not the EDU 42 has a cylinder discrimination abnormality (S432). The abnormality flag is stored in the RAM. When the cylinder discrimination of the EDU 42 is normal (S430: No), the ECU 40 turns off the abnormality flag (S434).

(Abnormal data transmission processing)
6 is executed by the ECU 40 every time a crank angle signal is input.

The ECU 40 determines from the abnormality flag stored in the RAM whether or not the EDU 42 has a cylinder discrimination abnormality (S440).
When the EDU 42 has a cylinder discrimination abnormality (S440: Yes), the ECU 40 obtains abnormal time data including the crank position and the engine speed stored in the control process of FIG. 3 executed at the timing of the immediately preceding crank angle signal. In step S442, it is determined whether it is the transmission timing of the abnormal data. The abnormal data is transmitted at a timing of every 30 ° CA such as 0 ° CA, 30 ° CA, and 60 ° CA, for example.

If it is the transmission timing of the abnormal data (S444: Yes), the ECU 40 transmits the abnormal data to the EDU 42 by CAN communication (S446).
(Cylinder discrimination processing at abnormal time)
7 is executed when the EDU 42 receives CAN communication from the ECU 40.

  When the CAN communication is received from the ECU 40, the EDU 42 determines whether or not the identifier in the received data frame represents the abnormal data transmitted from the ECU 40 (S450).

  When the abnormal data is received (S450: Yes), the EDU 42 determines whether or not the own apparatus has a cylinder discrimination abnormality based on the flag stored in the RAM (S452). When the apparatus itself is in cylinder discrimination abnormality (S452: Yes), the EDU 42 calculates the reception interval time from the equation (1) using the engine speed of the received data at the time of abnormality (S454). In equation (1), the reception interval angle is 30 ° CA. The time per rotation of the engine in Expression (1) is calculated from Expression (2).

Reception interval time [ms]
= (Reception interval angle / 360 ° CA) × Time per engine revolution (1)
Time per engine revolution [ms]
= 60 × 1000 / engine speed (2)
The reception interval time calculated from the equation (1) is obtained by converting the reception interval angle of 30 ° CA into time based on the engine speed. For example, when the engine speed is 3000 rpm, the reception interval time is about 1.67 ms.

  Next, the EDU 42 uses the reception interval time calculated by the equation (1) and uses the crank angle at which the engine rotates until the EDU 42 receives the abnormal data transmitted from the ECU 40 as the communication delay angle. (S456).

Communication delay angle = (CAN communication time / reception interval time) × reception interval angle (3)
In Expression (3), the CAN communication time is a time required for CAN transmission of a data frame of about 14 bytes with a data field of 8 bytes. If the communication speed of CAN communication is 1 Mbps, the CAN communication time is about 0.1 ms. A 0.1 ms CAN communication can be sufficiently performed with a reception interval time of 1.67 ms.

By substituting CAN communication time = 0.1 ms, reception interval time = 1.67 ms, and reception interval angle = 30 ° CA into equation (3), the communication delay angle is about 1.8 ° CA.
The EDU 42 performs cylinder discrimination from the crank position received in S450, the reception interval time calculated in S454 and S456, and the communication delay angle as follows (S458).

  For example, as shown in FIG. 8, when the ECU 40 receives a cylinder discrimination abnormality from the EDU 42 and the ECU 40 transmits abnormal data to the EDU 42 at a crank position of 300 ° CA, the EDU 42 transmits the data transmitted by the ECU 40 to the CAN communication time. Receive late. The abnormality data transmitted by the ECU 40 is 300 ° CA representing the crank position and the engine speed at 300 ° CA.

  The EDU 42 calculates a reception interval time corresponding to 30 ° CA from the equation (1), and uses a timer register and a timer counter with a (reception interval time / 5) corresponding to 6 ° CA as a crank interval time. An interrupt is generated by a compare match. When the crank interval time is set in the timer register and the count value of the timer counter matches the timer register, an interrupt occurs. Thereby, a pseudo crank angle signal can be generated at a crank angle interval of 6 ° CA.

  However, the interrupt corresponding to the crank position of 306 ° CA for the first time after the EDU 42 receives the abnormal data is set in the timer register by subtracting the CAN communication time corresponding to the communication delay angle from the crank interval time. To generate.

Thereafter, four interrupts are generated by setting the crank interval time in the timer register. The fourth interrupt from the interrupt corresponding to 306 ° CA is an interrupt corresponding to 330 ° CA.
Each time the abnormal data is received from the ECU 40 every 30 ° CA, the EDU 42 generates the first interrupt by subtracting the time corresponding to the communication delay angle from the crank interval time and setting it in the timer register. Four interrupts are generated by setting the crank interval time in the timer register.

  When the EDU 42 becomes abnormal in cylinder discrimination and first receives abnormal data from the ECU 40, the EDU 42 sets the count value of the crank counter according to the crank position of the pseudo crank angle signal to be generated first, and then counts up the crank counter. Start. Then, the EDU 42 performs cylinder discrimination based on the count value of the crank counter in the same manner as when cylinder discrimination is normal.

  The ECU 40 transmits control parameters to the EDU 42 by the control process of FIG. 3 even when the EDU 42 has a cylinder discrimination abnormality, as in the normal cylinder discrimination of the EDU 42. The EDU 42 injects fuel from the fuel injection valve 30 of the injection cylinder based on the injection command including the injection cylinder, the injection amount, and the injection timing among the control parameters.

  As described above, every time the abnormality data is received from the ECU 40 every 30 ° CA, the EDU 42 calculates the communication delay angle from the equations (1) to (3) based on the CAN communication time and the engine speed, and the first time. By setting the generation timing of the pseudo crank angle signal, cylinder discrimination can be performed by generating the pseudo crank angle signal at an appropriate timing.

  In the above-described embodiment, if the EDU 42 cannot normally receive the sensor signal of the crank angle sensor 52 or the cam angle sensor 54 due to disconnection, short circuit, noise, or the like, and the EDU 42 cannot perform cylinder discrimination, the EDU 42 The ECU 40 is notified that the cylinder discrimination is abnormal.

  When the cylinder discrimination abnormality is received from the EDU 42, the ECU 40 transmits the engine speed acquired on the ECU 40 side and the crank position acquired by the cylinder discrimination to the EDU 42 as abnormal data. As a result, the EDU 42 can perform cylinder discrimination based on the abnormal time data received from the ECU 40 even when the cylinder cannot be discriminated by the own apparatus.

As a result, even if the EDU 42 is in the cylinder discrimination abnormality, the cylinder discrimination is performed by the EDU 42, the engine 2 is started, and the operation of the engine 2 can be continued.
Further, only when the EDU 42 is abnormal in cylinder discrimination, the ECU 40 transmits abnormal data to the EDU 42. When the EDU 42 can perform cylinder discrimination normally, the ECU 40 does not transmit abnormal data to the EDU 42. Increase in the processing load can be suppressed.

  In addition, when the cylinder discrimination of the EDU 42 is abnormal, the ECU 40 transmits abnormal data to the EDU 42 every 30 ° CA as a predetermined crank angle interval, so that the crank indicated by the pseudo crank angle signal in the EDU 42 when the engine 2 is accelerated or decelerated. Even if the position is shifted, the crank position can be corrected every 30 ° CA.

[Other Embodiments]
The ECU 40 may determine whether or not the EDU 42 has a cylinder discrimination abnormality by using other methods in addition to the transmission information from the EDU 42. For example, when the ECU 40 cannot detect an increase in the engine speed within a predetermined time with respect to the injection amount commanded from the ECU 40 based on the accelerator opening and the engine speed, it is not injected due to a cylinder discrimination abnormality, or It may be determined that the injection is performed in the abnormal cylinder, and it may be determined that the EDU 42 has a cylinder discrimination abnormality.

  Further, in the above embodiment, when the EDU 42 is in the cylinder discrimination abnormality, every time the abnormal data is received from the ECU 40 at intervals of 30 ° CA, the EDU 42 calculates the communication delay angle based on the CAN communication time and the engine speed and receives it. The generation timing of the first pseudo crank angle signal is set for the crank position. In contrast, if the engine 2 can be started by generating a pseudo crank angle signal with the communication delay angle shifted, or if the operation of the engine 2 can be continued, the pseudo crank angle signal is output with the communication delay angle shifted. It may be generated.

  Further, when the EDU 42 can normally perform cylinder discrimination, for example, the engine speed and the crank position are collated with each other at a predetermined angular interval via the CAN communication between the ECU 40 and the EDU 42, and the data values of other devices are clearly within an allowable range. If the value exceeds the value, the other device is reset, or if the data values of the own device and the other device do not match, the data value on the safe side of the vehicle traveling may be adopted to perform the engine control.

  As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

2: diesel engine, 10: engine control system, 14: fuel supply pump, 20: common rail, 30: fuel injection valve, 40: ECU (first control device, first determination means, first communication means, first determination means) ), 42: EDU (second control device, second determination means, second communication means, second determination means)

Claims (5)

An engine that includes a first control device (40) and a second control device (42) that are communicably connected to each other, and the second control device executes engine control according to a control command transmitted from the first control device. A control device,
The first control device includes:
A crank angle sensor (52) for detecting the angular position of the crankshaft, and a first discriminating means (S400) for performing cylinder discrimination by inputting a sensor signal from the cam angle sensor (54) for detecting the angular position of the camshaft;
First determination means (S430, S440) for determining whether or not the second control device is in a cylinder discrimination abnormality in which cylinder discrimination is not possible;
First communication means (S446) for transmitting cylinder discrimination information generated by the first discriminating means to the second control device when the first discriminating means determines that the second control device is abnormal in cylinder discrimination;
Have
The second control device includes second determination means (S420) that performs cylinder determination by inputting the sensor signals from the crank angle sensor and the cam angle sensor.
An engine control device characterized by that. The second control device includes:
Second determination means (S420, S452) for determining whether or not the second control device has a cylinder discrimination abnormality;
When the second determining means determines that the second control device is in cylinder discrimination abnormality, the second communication means (S422) transmits to the first control device that the second control device is in cylinder discrimination abnormality. When,
Have
When the first communication means receives from the second control device that the second control device is in cylinder discrimination abnormality, the first determination means determines that the second control device is in cylinder discrimination abnormality;
The engine control apparatus according to claim 1.   When the second determining means determines that the second control device is abnormal in cylinder determination, the second determining means (S458) uses the cylinder determining information received from the first control device by the second communication means. 3. The engine control apparatus according to claim 2, wherein cylinder discrimination is performed based on the cylinder discrimination. The first determination unit and the second determination unit generate a rotation position of the crankshaft in one combustion cycle of the engine as cylinder determination information based on the sensor signal,
When the first determination means determines that the second control device has a cylinder determination abnormality, the first communication means determines the engine speed and the rotation position of the crankshaft generated by the first determination means. 2 Send to the control device,
When the second determination means determines that the second control device is abnormal in cylinder determination, the second determination means determines that the second communication means receives the engine speed and the crankshaft received from the first control device. A rotational position of the crankshaft used for cylinder discrimination is set based on the rotational position of the first communication means and the communication time between the first communication means and the second communication means.
The engine control apparatus according to claim 3.   When the first determination means determines that the second control device is abnormal in cylinder discrimination, the first communication means transmits the cylinder discrimination information to the second control device at a predetermined crank angle interval. The engine control device according to any one of claims 1 to 4.

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