JP4276003B2 - Reference signal monitoring method for vehicle internal combustion engine control - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reference signal monitoring method for a vehicle internal combustion engine, and more particularly to a method for monitoring a reference signal used for fuel injection of an internal combustion engine in a common rail system.
[0002]
[Prior art]
Conventionally, the control device for controlling the fuel injection of the internal combustion engine in the common rail system has made the injection timing synchronized with the rotation speed by software.
[0003]
In such fuel injection, the calculation of the cylinder specific injection start time is activated by a static interrupt signal. This static interrupt signal is generated in synchronization with the rotation angle by the tooth detector and the counting device. A dynamic interrupt signal is generated at an appropriate time before the injection start time calculated by the static interrupt signal, and a driving period, that is, an injection time length is calculated by the interrupt signal.
[0004]
Also, the detection of the rotational speed in the internal combustion engine is usually performed by a separate microcontroller or ASIC. In order to monitor whether the interrupt signal is operating normally, time monitoring or deadline monitoring is performed by a known method. Here, the deadline monitoring always accumulates time, resets the accumulated time when a signal scheduled up to a predetermined deadline is detected, and prepares for the next signal, and indicates an error if the scheduled signal is not detected. It is a monitoring method.
[0005]
Such monitoring is very suitable for time-synchronized systems. However, it is no longer sufficient to monitor the progress of event synchronization, which is critical to safety, such as the calculation and implementation of injection start and injection end times. Ensuring that the static and dynamic interrupt signals are working properly in terms of consistency, temporal position and number, especially in common rail systems, is an urgent task.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems of conventional vehicle internal combustion engine control, and an object of the present invention is to improve the safety by ensuring the normal operation of combustion injection, and to prevent engine damage. The present invention provides a new and improved reference signal monitoring method for controlling a vehicle internal combustion engine that can prevent the above-described problem.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, according to the first aspect of the present invention, of the reference signals used to calculate two control signals (E1, E2) for fuel injection of the internal combustion engine in the common rail system. , A static interrupt signal, which is a first reference signal, is generated according to a rotation angle; for each pulse of the first reference signal, a dynamic interrupt, which is a second reference signal delayed in time or angle according to a predetermined parameter, is generated. The first reference signal and the second reference signal are counted separately; the count value of the first reference signal and the count value of the second reference signal are periodically compared; A reference signal monitoring method for controlling a vehicle internal combustion engine is provided, characterized in that emergency measures and / or error recognition measures are activated according to deviations of the counted values.
[0008]
With this configuration, it is possible to quickly and reliably recognize an error in interrupt timing for both a static interrupt signal and a dynamic interrupt signal. This provides greater safety for the driver of the motor vehicle with the internal combustion engine and prevents engine damage due to error injection.
[0009]
Here, as the emergency measure, one or more measures selected from the group consisting of a reset operation of the CPU, switching to the emergency drive, and turning off the internal combustion engine may be provided. Further, as the error recognition measure, an error may be displayed and / or the error may be stored in the memory means. The operation of the emergency measures and / or the error recognition measures may be performed according to the error frequency.
[0010]
As such an error recognition measure, it is suitable to display an error or store the error in the memory means. In the subsequent diagnosis, the cause of the error and the error frequency can be reliably recognized from the memory means or the like. The operation of the emergency measures and error recognition measures is preferably performed according to the error frequency. For example, if a scheduled dynamic interrupt signal is lost, a CPU reset is activated, and if such a reset continues three times, switching to an emergency drive or complete turning off of the internal combustion engine is performed. Is called. Here, the complete turn-off of the internal combustion engine may be performed only when the emergency drive does not bring about a satisfactory driving behavior like the complete turn-off of the internal combustion engine.
[0011]
The calculation of the control signals (E1, E2) for the fuel injection may be performed only when the count value of the first reference signal is equal to the count value of the second reference signal.
[0012]
With such a configuration, it is possible to prevent the internal combustion engine from being damaged due to fuel error injection at an inappropriate time.
[0013]
Also, the first reference signal can activate the calculation of the fuel injection start time, and the second reference signal can activate the calculation of the fuel injection period or the fuel injection end time.
[0014]
With this configuration, the fuel injection period or the fuel injection end time with the most accurate parameters can be calculated in a short period before the injection start time.
[0015]
The fuel injection is one or more injections selected from the group consisting of pre-injection, main injection, and post-injection. A dedicated counting step and counting device are provided for each of the pre-injection, main injection, and post-injection. The first reference signal may sequentially activate the calculation of the injection start times for the different injections.
[0016]
By sequentially operating the calculation of the injection start time for each injection, a plurality of different injection timings can be overlapped based on one first reference signal, and a long time interval between the reference signal and the injection start time for each injection can be set. Can be shortened.
[0017]
Further, the angular interval of the first reference signal may be checked. Here, an angle pulse number (rotation angle) corresponding to the rotation angle is obtained from a counting device for counting angle pulses from the tooth detector driven by the internal combustion engine, and a predetermined number of angle pulses (rotation angle). A first reference signal is generated every time, and a pulse of an angle pulse value (total rotation angle) at the time of each first reference signal and an angle pulse value (previous total rotation angle) detected at the time of the previous first reference signal. It may be checked whether the difference (rotational angle difference) corresponds to a predetermined number of angular pulses (rotational angle).
[0018]
With this configuration, the counting device generates the first reference signal with the correct number of angular pulses, respectively, and checks whether the first reference signal is operating normally, and in some cases the emergency measures and / or errors indicated above. A recognition measure can also be activated.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.
[0020]
FIG. 1 is a signal waveform diagram illustrating the operation of each signal in a fuel injection system for an internal combustion engine. FIG. 2 is a simplified block diagram of a fuel injection system for an internal combustion engine.
[0021]
In such a fuel injection system for an internal combustion engine, the tooth detector 10 driven by a rotating camshaft generates a number of angle pulses in response to the rotation. This angle pulse is counted by a pulse counter 11 housed in a rotation speed detection module 12 as a counting device. In the rotation speed detection module 12, the rotation speed n of the internal combustion engine is also detected using the detected angle pulse. For this purpose, a separate microcontroller is provided.
[0022]
The rotation speed detection module 12 generates a static interrupt signal Is for each predetermined number of angle pulses. This static interrupt signal Is represents the first reference signal formed at equal intervals. The static interrupt signal Is is normally formed at equal intervals because the sensor value can be easily detected, but is not formed at equal intervals when unequal intervals are effective due to load distribution. Sometimes.
[0023]
In the first calculation stage 13 of the CPU 14 for calculating the fuel injection signal, the static interrupt signal Is is calculated for the generation of the dynamic interrupt signal Id and the injection start time, that is, the injection signal E1 start time. Activate calculation step B for calculation. Further, the dynamic interrupt signal Id as the second reference signal is for calculating the period c of the injection signal E1 in the second calculation stage 15 after the interval a and before the start of the injection signal E1. Activate calculation step B. The first calculation stage 13 and the second calculation stage 15 control the output stage 16. This output stage 16 controls at least one injection valve 17.
[0024]
The static interrupt signal Is is an appropriate dynamic interrupt signal Id that allows the start of driving for the pre-injection VE and the main injection HE (calculation of drive start time) and the drive period of the pre-injection VE and the main injection HE. The generation timing calculation is activated alternately. That is, the injection start time b and the dynamic interrupt signal Id generation time a are derived.
[0025]
Moreover, many pre-injection processes and many post-injection processes can also be provided in these injection processes.
[0026]
In order to confirm whether or not the interrupt signal as described above is operating normally, a dedicated interrupt counter 18 is provided for each injection type, for example, the pre-injection, the main injection, and the post-injection. The first interrupt counter 18 counts the increment of the static interrupt signal Is. In FIG. 2, for simplification, reference is made to one of the injections shown above. Accordingly, one first interrupt counter 18 is shown in FIG.
[0027]
Similar to the static interrupt signal Is, the second interrupt counter 19 counts the dynamic interrupt signal Id or the increment of each interrupt service routine. Again, an interrupt counter 19 can be provided for each injection type.
[0028]
When the dynamic interrupt signal Id is detected, the contents of the first interrupt counter 18 and the second interrupt counter 19 are compared using the comparator 20. In regular driving, the dynamic interrupt signal Id follows the static interrupt signal Is one-to-one. In such a case, the state of the interrupt counter must always be equal at the time of the dynamic interrupt signal Id. If this counter state is different, it is interpreted that normal operation is not taking place, and emergency measures and / or error recognition measures are activated.
[0029]
As this error recognition, such an error can also be recorded in the memory means 21. At the same time, the reset signal R for the CPU is activated and the calculation of the injection period and the processing of the program are not performed. Other emergency measures include, for example, switching to emergency driving by a plurality of error signals, or finally turning off the internal combustion engine. Further, a display device 22 for displaying an error is provided, and appropriate display can be performed step by step by incrementing the number of counters. For example, the display device 22 such as an LED can blink or light according to the number of errors, and more detailed display can be performed on the display device 22 such as a monitor display.
[0030]
In order to determine whether the rotation speed detection module 12 operates the static interrupt signal Is at the correct angle and the CPU 14 has responded at the correct time, the CPU 14 determines whether each interrupt is included in the static interrupt signal Is. The angle pulse value of the pulse counter 11 corresponding to the signal is referred to. Here, the pulse difference (rotation angle difference) between the angle pulse value (total rotation angle) in the static interrupt signal Is and the angle pulse value (previous total rotation angle) detected in the previous static interrupt signal Is. Is equivalent to a predetermined number of angle pulses (rotation angle, interrupt interval, or segment length). If the number of angle pulses is equal to the predetermined number, the injection start time calculation B and the programming of the dynamic interrupt signal Id can be started.
[0031]
In order to ensure normal operation by the reference signal corresponding to such rotation, the tooth detector 10 has a gap between at least one tooth. In this way, at least one angular pulse is generated during one revolution. Further, when the static interrupt signal Is is calculated, a missing tooth can be estimated by a computer.
[0032]
In FIG. 1, the bottom row shows the injection signals for other injection valves or cylinders. The calculation of the injection signal is activated by the static interrupt signal Is as described above. The time and interval obtained in the calculation interval B are similarly indicated by symbols a ′, b ′ and c ′. Thus, the static interrupt signal Is sequentially activates the calculation of the injection start time for each different injection.
[0033]
As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to this example. It will be obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.
[0034]
【The invention's effect】
As described above, according to the present invention, it is possible to improve safety and prevent engine damage by ensuring normal operation of combustion injection.
[Brief description of the drawings]
FIG. 1 is a signal waveform diagram illustrating the operation of each signal in a fuel injection system for an internal combustion engine.
FIG. 2 is a simplified block diagram of a fuel injection system for an internal combustion engine.
[Explanation of symbols]
10 tooth detector 11 pulse counter 12 counting device (rotation speed detection module)
13 First calculation stage 14 CPU
15 Second calculation stage 16 Output stage 17 Injection valve 18 First interrupt counter 19 Second interrupt counter 20 Comparator 21 Memory means 22 Display device Is First reference signal (static interrupt signal)
Id Second reference signal (dynamic interrupt signal)
B Calculation step E1 First injection signal E2 Second injection signal

Claims (9)

Of the reference signals used to calculate the two control signals (E1, E2) for fuel injection of the internal combustion engine in the common rail system, a static interrupt signal as a first reference signal is generated according to the rotation angle. ;
For each pulse of the first reference signal, a dynamic interrupt signal that is a second reference signal delayed in time or angle according to a predetermined parameter is generated;
The first reference signal and the second reference signal are counted separately;
The count value of the first reference signal and the count value of the second reference signal are periodically compared;
Activating emergency measures and / or error recognition measures according to the deviation of the compared count values;
A reference signal monitoring method for controlling a vehicle internal combustion engine, wherein the first reference signal operates to calculate a fuel injection start time, and the second reference signal operates to calculate a fuel injection period or a fuel injection end time. .   2. The emergency measure includes one or more measures selected from the group consisting of a CPU reset operation, switching to an emergency drive, and turning off an internal combustion engine. Of reference signal for vehicle internal combustion engine control.   3. The vehicle internal combustion engine control reference signal monitoring method according to claim 1, wherein an error is displayed as the error recognition measure and / or the error is stored in a memory means.   The reference signal monitoring method for vehicle internal combustion engine control according to any one of claims 1 to 3, wherein the operation of the emergency measure and / or the error recognition measure is performed according to an error frequency.   2. The calculation of the control signal (E1, E2) for fuel injection is performed only when the count value of the first reference signal is equal to the count value of the second reference signal. 5. A reference signal monitoring method for controlling a vehicle internal combustion engine according to any one of claims 1 to 4. The fuel injection is one or more injections selected from the group consisting of pre-injection, main injection, and post-injection, and a dedicated counting step and counting device are provided for each of the pre-injection, main injection, and post-injection. 6. The reference signal monitoring method for controlling a vehicle internal combustion engine according to claim 1, wherein the reference signal is monitored. The fuel injection is one or more injections selected from the group consisting of pre-injection, main injection, and post-injection, and the first reference signal sequentially activates calculation of injection start times for the different injections. A reference signal monitoring method for controlling a vehicle internal combustion engine according to any one of claims 1 to 6 , wherein the reference signal is monitored. 8. The vehicle internal combustion engine control reference signal monitoring method according to claim 1 , wherein an angular interval of the first reference signal is checked. An angle pulse number (rotation angle) corresponding to a rotation angle is obtained from a counting device that counts angle pulses from a tooth detector driven by the internal combustion engine,
A first reference signal is generated for each predetermined number of angle pulses (rotation angle),
A pulse difference (rotation angle difference) between an angle pulse value (total rotation angle) at each first reference signal and an angle pulse value (previous total rotation angle) detected at the previous first reference signal is determined in advance. 9. The reference signal monitoring method for controlling a vehicle internal combustion engine according to claim 8 , wherein it is checked whether the angle pulse number (rotation angle) corresponds to the determined number.

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