JP2015001200A - Electronic control device for vehicle and electronic control method for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent breakage of an engine by properly controlling a fuel without making a mistake in determining a crank angle even when any abnormality occurs in a function of an A/D converter or the like inside a microcomputer.SOLUTION: An electronic control device for a vehicle includes a crank angle detecting section (3001), a cycle measuring section (3003) for measuring an interruption processing cycle, an interruption processing time measuring section (3004) for measuring an interruption processing time, a fuel cut determining section (3005) for determining the execution of fuel cut when the interruption processing time becomes longer than a time obtained by subtracting a margin from the interruption processing cycle, a cylinder determining section (3002) for determining whether a present interruption processing cycle is fuel injection timing or not, and a fuel output section (3006) for controlling a fuel injection valve by setting a valve opening time of the fuel injection valve to 0, when the cylinder determining section determines that the present interruption processing cycle is the fuel injection timing, and the fuel cut determining section determines the execution of the fuel cut, in the present interruption processing cycle.

Description

  The present invention relates to an electronic control device that controls an engine, and more particularly to an electronic control for a vehicle that prevents engine damage when an abnormality occurs in a microcomputer (hereinafter simply referred to as a microcomputer) built in the control device. The present invention relates to an apparatus and a vehicle electronic control method.

  The electronic control unit determines the amount of fuel supplied to the engine, the timing of fuel injection, the energization time and ignition timing of the ignition coil, and the amount of air taken in by the engine so that the engine can be operated in an appropriate state. It is necessary to control with.

  For this reason, the processing in the electronic control device is equipped with main processing that repeatedly executes the same processing regardless of external signals, interrupt processing that is performed in synchronization with external signals, and internal processing. It consists of fixed-time processing that is performed at regular intervals by a timer built in the microcomputer. In particular, in order to control the timing of fuel injection and the timing of ignition, it is necessary to perform a control operation in interrupt processing synchronized with the crank angle signal. This interrupt processing will be described below.

  The crank angle signal is obtained by reading an output signal of a crank angle signal plate attached to the crankshaft of the engine with a crank angle sensor, and this signal is sent to an electronic control unit. The rotation speed of the crankshaft (physically it should be referred to as the rotation speed, but according to convention, here referred to as the rotation speed) is generally referred to as the engine rotation speed, and is hereinafter referred to as the engine rotation speed.

  When the engine speed increases, the interval between the crank angle signals decreases in inverse proportion to the engine speed, but the interrupt processing time synchronized with the crank angle signal is substantially constant regardless of the engine speed. That is, as the engine speed increases, the ratio of the interrupt processing time to the crank angle signal interval relatively increases. For this reason, at the time of high engine rotation, it is necessary to adjust the amount of interrupt processing so that the time for interrupt processing is completed within the interval of the crank angle signal.

  For example, there is a conventional technique that considers a case where a plurality of interrupts having different interrupt levels occur simultaneously when an interrupt occurs (see, for example, Patent Document 1). In this case, the simultaneous interrupts (multiple interrupts) are executed in order from the processing with the highest interrupt level by the interrupt processing mechanism. The processing to be executed is composed of a plurality of processing units, and the control means sets the processing units to be executed at each interrupt level.

  As a result, when the interrupt level set for each processing unit becomes an execution target by the interrupt control mechanism, that processing unit is executed. Therefore, the amount of interrupt processing can be adjusted appropriately according to the situation.

JP 2003-345404 A

However, the prior art has the following problems.
According to the prior art, there is a process of calculating water temperature information during an interrupt process synchronized with a crank angle signal. In order to obtain appropriate water temperature information at the timing of interrupt processing, it is necessary to A / D convert the input value from the water temperature sensor during the interrupt processing.

  For this reason, when an abnormality occurs in the A / D converter inside the microcomputer and the A / D conversion processing time is extended, the interrupt processing cannot be completed at the expected time, and is completed within the interval of the crank angle signal. Disappear. As a result, the determination of the crank angle is incorrect, and fuel control and ignition control are performed on the cylinders that are not the target cylinders. In the worst case, there is a problem that the engine is damaged.

  The present invention has been made in view of such a problem. Even when an abnormality occurs in the function of an A / D converter or the like in the microcomputer, fuel control to the target cylinder can be performed without erroneous determination of the crank angle. It is an object of the present invention to obtain a vehicle electronic control device and a vehicle electronic control method capable of appropriately performing ignition control and preventing engine damage.

  An electronic control device for a vehicle according to the present invention is an electronic control device for a vehicle including an interrupt processing unit that controls a fuel injection valve at an interrupt timing synchronized with a crank angle signal from a crank angle sensor, the interrupt processing unit Interrupts according to the current engine speed by measuring the crank angle signal from the crank angle sensor and measuring the interval between the crank angle signal detected last time and the crank angle signal detected this time. The cycle measurement unit that measures the processing cycle, the interrupt processing time measurement unit that measures the actual interrupt processing time in the previous interrupt processing cycle, and the interrupt processing time that is measured by the interrupt processing time measurement unit If it is more than the time obtained by subtracting the margin specified in advance from the interrupt processing cycle measured A fuel cut determination unit for determining whether or not, a cylinder determination unit for determining whether or not the current interrupt processing cycle is a fuel injection timing based on the crank angle signal detected by the crank angle detection unit, and a current interrupt In the processing cycle, when it is determined that the fuel injection timing is determined by the cylinder determination unit and the fuel cut determination unit determines to perform the fuel cut, the valve opening time of the fuel injection valve is set to 0, And a fuel output unit for controlling the fuel injection valve.

  In addition, the vehicle electronic control method according to the present invention includes an interrupt processing step executed by a microcomputer for controlling the fuel injection valve at an interrupt timing synchronized with a crank angle signal from a crank angle sensor. In the electronic control method, the interrupt processing step sequentially stores the crank angle detection step for detecting the crank angle signal from the crank angle sensor and the time at which the crank angle signal is detected in the storage unit, which is stored in the storage unit. A cycle measurement step for measuring an interrupt processing cycle according to the current engine speed by measuring the interval between the time when the previous crank angle signal was detected and the time when the current crank angle signal was detected, and the previous interrupt processing Interrupt processing time actually taken by storing the start time and end time of interrupt processing in the storage unit in the cycle The interrupt processing time measurement step to be measured and the interrupt processing time measured in the interrupt processing time measurement step are equal to or more than the time obtained by subtracting the margin time specified in advance from the interrupt processing cycle measured in the cycle measurement step. In this case, it is determined whether or not the current interrupt processing cycle is the fuel injection timing based on the fuel cut determination step for determining that the fuel cut is to be performed and the crank angle signal detected in the crank angle detection step. In the cylinder discrimination step and the current interruption processing cycle, when it is determined that the fuel injection timing is determined by the cylinder discrimination step and the fuel cut is determined by the fuel cut determination step, the fuel injection valve is opened. A fuel output step for controlling the fuel injection valve by setting the time to 0

  According to the present invention, when it is determined that the interrupt processing time becomes equal to or greater than a value obtained by subtracting a predetermined margin from the interrupt processing occurrence interval according to the current engine speed, the fuel injector is opened. By setting the valve time to 0, the output of the engine is suppressed, so that if any abnormality occurs in the function of the A / D converter inside the microcomputer, the crank angle can be determined without error. It is possible to obtain a vehicular electronic control device and a vehicular electronic control method capable of appropriately performing fuel control and ignition control to the cylinder and preventing engine damage.

It is explanatory drawing which shows the control system of the electronic controller for vehicles in Embodiment 1 of this invention. It is a figure which shows the internal structure of the electronic controller for vehicles in Embodiment 1 of this invention. It is a block diagram showing the flow of control of the electronic controller for vehicles in Embodiment 1 of the present invention. It is the flowchart which showed the initialization process of the control program which CPU in the control apparatus in Embodiment 1 of this invention performs. It is the flowchart which showed the main process of the control program which CPU in the control apparatus in Embodiment 1 of this invention performs. It is a flowchart which shows the flow of a series of interruption processes in the electronic controller for vehicles in Embodiment 1 of this invention. It is a figure showing the relationship between the engine speed in Embodiment 1 of this invention, and a crank angle signal period.

  Hereinafter, preferred embodiments of an electronic control device for a vehicle and an electronic control method for a vehicle according to the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is an explanatory diagram showing a control system of the vehicle electronic control device according to Embodiment 1 of the present invention. In the electronic control system shown in FIG. 1, the control device 1 is rotated in synchronization with the coolant temperature sensor 21 of the engine E, the intake pressure sensor 22 of the intake pipe E1, the throttle opening sensor 23, the accelerator opening sensor 24, and the crankshaft. The crank angle sensor 25 that generates 36 high-level signals per revolution and the air-fuel ratio sensor 26 of the exhaust pipe E2 and the like are input from the crank angle signal plate E3 that performs, and the intake pipe E1 based on these detection results. Output signals are issued to the fuel injection valve 31, the igniter 32, the electronic throttle motor, etc., and the engine is controlled.

  A distributor 33 for sequentially distributing the high voltage generated by the igniter 32 to an ignition plug (not shown) of each cylinder is disposed between the igniter 32 and the ignition coil 34.

  FIG. 2 is a diagram showing an internal configuration of the vehicle electronic control unit according to Embodiment 1 of the present invention. The control device 1 includes a microcomputer 11, input interface circuits 12 to 14, an output interface circuit 15, a ROM 16 storing control programs and data, and power supply circuits 17 and 18.

  Further, the microcomputer 11 functions as a CPU 111 that performs a control operation according to a control program described later, a counter 112 that functions as a timer, a timer 113 that measures the rotation period of the engine, an A / D converter 114, an input port 115, a work memory, and the like. A RAM 116 and an output port 117 are included.

  A signal from the crank angle sensor 25 is input to the input interface circuit 12. Based on this signal, the CPU 111 calculates the rotational speed of the engine E (hereinafter also simply referred to as the rotational speed). The high level signal of the crank angle sensor 25 is also used as an interrupt signal for a control program described later.

  Signals from the coolant temperature sensor 21 and the intake pressure sensor 22 are input to the input interface circuit 13. Furthermore, various digital signals 27 such as A / C SW are input to the input interface circuit 14.

  The fuel injection time width pulse output from the output port 117 is output to the fuel injection valve 31 via the output interface circuit 15. Further, power is supplied to the microcomputer 11 via the power supply circuit 17. Further, backup power is supplied to the RAM 116 via the power circuit 18.

  FIG. 3 is a block diagram showing a control flow of the vehicle electronic control unit according to Embodiment 1 of the present invention. The control device 1 shown in FIG. 3 includes two processing units: an interrupt processing unit 3100 that detects a crank angle sensor signal and is activated in synchronization with the signal, and a main processing unit 3101.

  The interrupt processing unit 3100 includes a crank angle detection unit 3001, a cylinder determination unit 3002, a cycle measurement unit 3003, an interrupt processing time measurement unit 3004, a fuel cut determination unit 3005, and a fuel output unit 3006. The main processing unit 3101 includes an engine speed calculation unit 3007, an intake air amount calculation unit 3008, and a fuel injection amount calculation unit 3009.

  First, the interrupt processing unit 3100 will be described. The crank angle detection unit 3001 detects the crank angle signal from the crank angle sensor 25, sets the interrupt process start time (Ts) stored in the previous interrupt process as (Tso), and the time when the current crank angle signal is detected. The interrupt processing start time (Ts) is stored in the RAM 116 and crank angle information is obtained.

  The cylinder discrimination unit 3002 discriminates the cylinder that is currently in the compression stroke from the crank angle information obtained by the crank angle detection unit 3001. The cycle measuring unit 3003 calculates the cycle of the crank angle signal from the interrupt processing start time (Ts) stored in the RAM 116 by the crank angle detection unit 3001 and the interrupt processing start time (Tso) stored in the previous interrupt processing.

  The interrupt processing time measuring unit 3004 obtains the interrupt processing time from the interrupt processing start time (Ts) stored in the RAM 116 by the crank angle detection unit 3001 and the interrupt processing end time (Te) described later.

  The fuel cut determining unit 3005 compares the crank angle signal cycle obtained by the cycle measuring unit 3003 with the interrupt processing time obtained by the interrupt processing time measuring unit 3004 to determine whether or not to perform fuel cut.

  The fuel output unit 3006 converts a fuel injection amount obtained by a fuel injection amount calculation unit 3009 described later into a time width pulse, and outputs it to the fuel injection valve 31 based on the cylinder information obtained by the cylinder discrimination unit 3002. . However, the fuel output unit 3006 sets the time width pulse to 0 when the fuel cut determination unit 3005 determines that the fuel is cut.

  Next, the main processing unit 3101 will be described. The engine speed calculation unit 3007 calculates the engine speed based on the cycle of the crank angle signal obtained by the cycle measurement unit 3003.

  The intake air amount calculation unit 3008 calculates the intake air amount based on the signal from the intake pressure sensor 22. Further, the fuel injection amount calculation unit 3009 calculates the fuel injection amount from the engine speed obtained by the engine speed calculation unit 3007, the intake air amount obtained by the intake air amount calculation unit 3008, and the like.

  FIG. 4 is a flowchart showing the initialization process of the control program executed by the CPU 111 in the control device 1 according to the first embodiment of the present invention, which is a process executed when the control device 1 is activated. When this process is started, first, in step S400, the CPU 111 sets the operating environment of the microcomputer 11. Next, in step S410, the CPU 111 initializes the RAM 116, and then proceeds to the main process shown in FIG.

  FIG. 5 is a flowchart showing a main process of a control program executed by CPU 111 in control device 1 according to the first embodiment of the present invention, and is a process executed after activation of control device 1. First, in step S500, the CPU 111 calculates the engine speed from an interrupt cycle (Ts-Tso) described later. This processing corresponds to the processing by the engine speed calculation unit 3007 in FIG.

  Next, in step S510, the CPU 111 calculates the fuel injection amount based on the detection results of the cooling water temperature sensor 21, the intake pressure sensor 22, and the like. This processing corresponds to the processing by the intake air amount calculation unit 3008 and the fuel injection amount calculation unit 3009 in FIG. Based on this calculation result, the valve opening time of the fuel injection valve 31 is controlled.

  Further, in step S520, CPU 111 calculates a target electronic throttle valve opening based on detection results of cooling water temperature sensor 21, accelerator opening sensor 24, and the like. Then, the CPU 111 calculates the electronic throttle valve motor operation amount 35 from the calculation result of the target electronic throttle valve opening and the detection result of the throttle opening sensor 23. The electronic throttle motor is controlled based on the calculation result. When the electronic throttle valve motor operating amount 35 is calculated, the process returns to step S500, and is repeatedly executed thereafter.

  FIG. 6 is a flowchart showing a flow of a series of interrupt processing in the vehicle electronic control apparatus according to Embodiment 1 of the present invention, and corresponds to a series of processes of the interrupt processing unit 3100 in the block diagram shown in FIG. To do. First, in step S600, the crank angle detection unit 3001 stores the previous interrupt processing start time (Ts) as (Tso) in the RAM 116.

  Next, in step S610, the cycle measuring unit 3003 calculates an interrupt cycle from the previous interrupt processing start time (Tso) and the current interrupt processing start time (Ts).

  Next, in step S620, the fuel cut determination unit 3005 compares a time obtained by subtracting a margin K, which will be described later, from the cycle of the crank angle signal (interrupt cycle), and the interrupt processing time. Note that the interrupt processing time used here can be a value specified in the design as an initial value, and the second and subsequent times are actually required in the previous interrupt cycle calculated in step S695 described later. Interrupt processing time can be used.

  Then, the fuel cut determination unit 3005 proceeds to step S630 when the interruption processing time is longer and when both are equal, and sets 1 in the fuel cut flag. On the other hand, if the interrupt processing time is shorter, the fuel cut determination unit 3005 skips step S630 and proceeds to step S640.

  Next, in step S640, the cylinder determination unit 3002 determines whether or not the current interruption process is the fuel injection timing. If it is the fuel injection timing, in step S650, the fuel output unit 3006 converts the fuel injection amount obtained in the calculation of the fuel injection amount in the main processing unit 3101 (S510) into a time width pulse. . On the other hand, if it is not the fuel injection timing, the process proceeds to step S692 without performing the process related to the fuel injection.

  In step S660, the fuel output unit 3006 determines whether the fuel cut flag is 1. If the fuel cut flag is 1, the fuel output unit 3006 replaces the time width pulse with 0 in step S670. On the other hand, if the fuel cut flag is not 1, step S670 is skipped and the process proceeds to step S680.

  Next, in step S680, the fuel output unit 3006 outputs the time width pulse set in step S650 or step S670 to the output port 117. Next, in step S690, the fuel output unit 3006 clears the fuel cut flag to 0 in preparation for the next interruption process.

  Next, in step S692, the interrupt processing time measuring unit 3004 stores the value of the timer 113 in the RAM 116 as (Te) as the end time of the interrupt processing. Further, in step S695, the interrupt processing time measuring unit 3004 calculates the interrupt processing time from (Te) stored in the previous step S692 and (Ts) stored in the RAM 116 in the previous step S600. To do. Then, after these series of interrupt processes are completed, the process returns to the main process.

  Next, the margin K used in step S620 in FIG. 6 will be described with reference to FIG. FIG. 7 is a diagram showing the relationship between the engine speed and the crank angle signal period in the first embodiment of the present invention. The vertical axis represents the crank angle signal period [μs], and the horizontal axis represents the engine speed [rpm]. A dotted line 7001 in FIG. 7 represents the interrupt processing time synchronized with the crank angle signal. A solid line 7002 is a crank angle signal cycle (interrupt cycle) in a 4-cylinder 4-cycle engine.

  The margin K represents the margin of the interrupt processing time with respect to the cycle of the crank angle signal, and a constant value is set for the cycle. A solid line 7003 in FIG. 7 is a time obtained by subtracting the interrupt processing time margin K from the crank angle signal period. In other words, in the present invention, the magnitude relationship between the interrupt period and the interrupt processing time is not simply compared, but the magnitude relationship is compared in consideration of the margin K.

Specifically, the margin K is obtained as follows. The cycle of the crank angle signal can be obtained by the following expression (1) from the engine speed.
Period [sec] = 60 / Ne [rpm] / 36 (1)

  Here, Ne is the engine speed, and 36 is the number of high level signal outputs per revolution of the crank angle signal plate. If the maximum number of revolutions allowed by the engine is set to 7000 rpm and substituted into the above equation (1), the required period is 0.000238 [sec], that is, 238 [μsec]. Therefore, as an example, when 5% of the obtained period is the margin K, the margin K is about 12 [μsec].

  As described above, according to the first embodiment, the time actually taken for the interrupt processing in the previous interrupt cycle is obtained by subtracting the predetermined margin K from the interrupt processing occurrence interval according to the current engine speed. If it is determined that the value exceeds the value, the engine output can be suppressed by setting the valve opening time of the fuel injection valve to zero.

  Furthermore, by setting the margin K according to the application target of the vehicle electronic control device, the condition for suppressing the engine output can be set to a value suitable for the application target, and the engine output is appropriately suppressed. can do.

  As a result, especially when an abnormality occurs in the function of the A / D converter or the like inside the microcomputer when the engine speed is high, fuel control to the target cylinder can be performed without erroneous determination of the crank angle. An electronic control device for a vehicle that can appropriately perform ignition control and prevent engine damage can be realized.

  DESCRIPTION OF SYMBOLS 1 Control apparatus (electronic control apparatus for vehicles), 11 Microcomputer, 12-14 Input interface circuit, 15 Output interface circuit, 16 ROM, 17, 18 Power supply circuit, 21 Cooling water temperature sensor, 22 Intake pressure sensor, 23 Throttle opening sensor , 24 accelerator opening sensor, 25 crank angle sensor, 26 air-fuel ratio sensor, 27 various digital signals, 31 fuel injection valve, 32 igniter, 33 distributor, 34 ignition coil, 35 electronic throttle valve motor operating amount, 111 CPU, 112 counter , 113 timer, 114 A / D converter, 115 input port, 116 RAM, 117 output port, 3001 crank angle detection unit, 3002 cylinder discrimination unit, 3003 period measurement unit, 3004 interrupt processing time measurement unit, 3005 DOO determination unit, 3006 fuel output unit, 3007 an engine speed calculating unit, 3008 intake air quantity calculating section, 3009 a fuel injection amount calculation portion, 3100 interrupt processing section, 3101 the main processor.

Claims (3)

An electronic control device for a vehicle including an interrupt processing unit that controls a fuel injection valve at an interrupt timing synchronized with a crank angle signal from a crank angle sensor,
The interrupt processing unit
A crank angle detector for detecting a crank angle signal from the crank angle sensor;
A cycle measuring unit that measures an interrupt processing cycle according to the current engine speed by measuring the interval between the crank angle signal detected last time and the crank angle signal detected this time;
An interrupt processing time measurement unit that measures the interrupt processing time actually taken in the previous interrupt processing cycle;
When the interrupt processing time measured by the interrupt processing time measuring unit is equal to or longer than a time obtained by subtracting a margin time defined in advance as a margin from the interrupt processing cycle measured by the cycle measuring unit, A fuel cut determination unit that determines to perform cutting;
A cylinder discriminating unit that determines whether or not the current interrupt processing cycle is a fuel injection timing based on the crank angle signal detected by the crank angle detecting unit;
In the current interrupt processing cycle, when it is determined by the cylinder determining unit that the fuel injection timing is reached and the fuel cut determining unit determines that the fuel cut is to be performed, the fuel injection valve is opened. A vehicle electronic control device comprising: a fuel output unit configured to control the fuel injection valve by setting time to zero. The vehicle electronic control device according to claim 1,
The fuel cut determination unit determines whether or not to perform a fuel cut by using a value obtained by multiplying an interrupt processing cycle at a maximum engine speed by a preset ratio as the margin. An electronic control method for a vehicle comprising an interrupt processing step executed by a microcomputer to control a fuel injection valve at an interrupt timing synchronized with a crank angle signal from a crank angle sensor,
The interrupt processing step includes
A crank angle detection step of detecting a crank angle signal from the crank angle sensor;
The time at which the crank angle signal is detected is sequentially stored in the storage unit, and the current time is detected by measuring the interval between the time at which the previous crank angle signal is detected and the time at which the current crank angle signal is detected. A cycle measuring step for measuring an interrupt processing cycle according to the engine speed;
In the previous interrupt processing cycle, by storing the start time and end time of interrupt processing in the storage unit, an interrupt processing time measuring step for measuring the actual interrupt processing time,
When the interrupt processing time measured in the interrupt processing time measuring step is equal to or longer than a time obtained by subtracting a margin time defined in advance as a margin from the interrupt processing cycle measured in the cycle measuring step, A fuel cut determination step for determining that cutting is to be performed;
A cylinder determining step of determining whether or not the current interrupt processing cycle is a fuel injection timing based on the crank angle signal detected in the crank angle detecting step;
If it is determined that the fuel injection timing is determined by the cylinder determination step and the fuel cut is determined by the fuel cut determination step in the current interrupt processing cycle, the fuel injection valve is opened. And a fuel output step of controlling the fuel injection valve by setting time to 0.

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