JP5047142B2 - Control method when combustion diagnosis signal of internal combustion engine is abnormal - Google Patents

Description

  The present invention relates to a control method when an internal combustion engine including a gas engine and a diesel engine has an abnormality in a combustion diagnosis signal, and more particularly, an input including an analog / digital converter that receives a signal from a combustion diagnosis device and transmits the signal to an ignition timing control device. The present invention relates to a control method in the case where a combustion diagnosis signal abnormality occurs due to a failure of a part.

  In an internal combustion engine, particularly a gas engine using gas as the main fuel, it is essential to detect and diagnose the combustion state in the combustion chamber, and to control the combustion ignition timing and the fuel injection amount suitable for the result of the combustion diagnosis. Immediately detect and respond quickly to malfunctions related to combustion, such as the occurrence of knocking due to indoor misfires and extinguishing, and non-uniform mixture concentration, and premature ignition due to residual unburned fuel in the cylinder. It is required to be treated.

  As such a combustion state diagnostic device, for example, in Patent Document 1, the presence or absence of premature ignition is determined based on a reference pressure value based on a pre-ignition threshold value of a pre-set in-cylinder pressure, and premature ignition occurs. In this case, the abnormality determination logic of the in-cylinder pressure detector is stopped, and when the pre-ignition does not occur, the abnormality determination logic of the in-cylinder pressure detector makes a determination. A technique for avoiding misdiagnosis due to pre-ignition cause contamination and preventing occurrence of misdiagnosis of combustion is shown.

  As shown in FIG. 4, the combustion diagnostic device for an internal combustion engine of Patent Document 1 uses a signal from a cylinder pressure detector 12 provided in each of a plurality of combustion cylinders 10 of the engine, and uses a combustion diagnostic device 14. Thus, abnormal combustion such as occurrence of premature ignition in each combustion cylinder 10 is detected. As a result, analog signals such as high pressure (for example, H), low pressure (for example, L), and normal pressure (for example, N) are detected. It is sent to the input unit 16. Then, the input unit 16 including the analog / digital conversion unit converts the sent analog signal into a digital signal and sends it to the ignition timing control unit 18 to delay the ignition timing (retard) when the pressure is high (H). When the pressure is low (L), the ignition timing is advanced (advanced) to control and drive the internal combustion engine 20.

JP 2007-32407 A

  However, since the ignition timing control unit 18 shown in FIG. 4 receives and controls that the signal from the input unit 16 is always correct, for example, the combustion diagnostic device 14 operates normally and is input to the input unit 16. Although the signal is transmitted, if the element constituting the input unit 16 fails due to secular change or the like, the ignition timing control unit 18 may continue to operate with an incorrect signal.

  That is, if the signal that the input unit 16 has sent to the ignition timing control unit 18 before the failure is, for example, a signal that the combustion indicating that the pressure is low (L) is weak, the ignition timing control unit 18 receives the signal. And the ignition timing is advanced (advanced) at present because the combustion is weak, so that the combustion is increased for each cycle of the engine and the cylinder pressure is increased. increase. For this reason, in the worst case, for example, a gas engine with a sub chamber may cause serious troubles such as sub chamber melting, and a part of the sub chamber that has been damaged may damage the cylinder liner or the exhaust valve. There is a risk of collision or intrusion into the turbocharger.

  Therefore, in the present invention, it is possible to provide a control method when an internal combustion engine combustion diagnosis signal is abnormal, which can prevent such a serious trouble even if an element constituting the input unit 16 breaks down. It is a problem.

In order to solve the above problems, a control method for an abnormality of a combustion diagnosis signal of an internal combustion engine according to the present invention is as follows.
Based on the in-cylinder pressure detection value detected by the in-cylinder pressure detector, the combustion diagnosis device diagnoses the combustion state in the cylinder, and converts the diagnosis result into a digital signal at an input unit including an analog / digital conversion unit. When it is sent to the ignition timing control unit, and the detected pressure value in the cylinder indicates low pressure (L) in the cylinder, the ignition timing is advanced (advance) and the pressure high (H) is indicated. In the combustion diagnosis method for a combustion internal combustion engine, which is slow (retarded) in case and normal pressure (N) is left as it is, when an abnormality occurs in the input portion, the combustion diagnosis signal of the internal combustion engine is abnormal. A control method,
When a signal indicating an abnormality is given to the input unit with a failure self-diagnosis function, or when there is no response for a predetermined time with respect to a data transfer request periodically issued from the ignition timing control unit, It is determined that the input unit is abnormal, and the ignition timing control unit makes the current cylinder pressure normal so that the ignition timing is neither retarded nor advanced.

  In this way, when the signal indicating abnormality is sent with the input unit having a self-diagnosis function, or when there is no response for a predetermined time to a data transfer request that is periodically issued, the input unit determines that there is an abnormality, and the ignition timing By making the current cylinder pressure normal by the control unit so that it is neither retarded nor advanced, the combustion increases to increase the cylinder pressure, and the sub-chamber melts down in a gas engine with a sub-chamber, etc. Thus, it is possible to prevent the occurrence of such a serious trouble and to provide a control method at the time of abnormality of the combustion diagnosis signal of the internal combustion engine that can always realize stable combustion.

  As described above, the control method when the combustion diagnosis signal of the internal combustion engine according to the present invention is abnormal prevents the occurrence of trouble based on the abnormality immediately when the abnormality occurs in the input, so that the internal combustion engine that can always realize stable combustion The control method when the combustion diagnosis signal is abnormal.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Absent.

FIG. 1 is a block diagram for explaining a combustion diagnostic apparatus for an internal combustion engine according to the present invention. Components similar to those in FIG. 4 are given the same reference numerals, but will be described briefly. Reference numeral 10 denotes a plurality of combustion cylinders of the engine, and signals from the cylinder pressure detectors 12 provided in each of them are indicated. The corresponding combustion diagnosis device 14 detects abnormal combustion such as occurrence of premature ignition in each combustion cylinder 10. The diagnosis result is sent to the input unit 16 as an analog signal such as a high pressure (for example, H), a low pressure (for example, L), or a normal pressure (for example, N). The sent analog signal is converted into a digital signal and sent to the ignition timing control unit 18. Then, the ignition timing control unit 18 delays (retards) the ignition timing when the pressure is high (H), and accelerates (advances) the ignition timing when the pressure is low (L), and at normal pressure (N). As it is, the internal combustion engine 20 is controlled and driven without being retarded or advanced.
In the following description, the present invention will be described by taking the case of torch ignition with pilot fuel as an example. However, it is obvious that the present invention can be similarly implemented even with an electric ignition system.

In the present invention, the input unit 16 is provided with an input normality determination unit 22 that performs a self-diagnosis function for finding a failure of the entire circuit including the analog / digital conversion unit, whereby the ignition timing control unit 18 is Appropriate processing can be performed.
In place of the input normality determination unit 22, for example, when there is no response for a predetermined time with respect to a data transfer request periodically issued from the ignition timing control unit 18, it is determined that the input unit 16 is abnormal. Also good.

  Next, before explaining the control method when the combustion diagnostic signal is abnormal according to the present invention, the schematic configuration of the combustion diagnostic apparatus shown as 14 in FIG. This will be briefly described with reference to the configuration diagram showing the overall configuration.

  In FIG. 2, 30 is an engine body of a gas engine, 32 is a piston, 34 is a crankshaft, 36 is a combustion chamber, 38 is an intake valve, 40 is an exhaust valve, and 42 is an exhaust pipe. An intake pipe 44 communicates with the intake valve 38. A gas injection device 48 for injecting fuel gas into the air (intake air) flowing through the intake pipe 44 is provided in the middle of the intake pipe 44. Yes. Reference numeral 50 denotes a gas supply pipe that connects a fuel gas tank (not shown) that stores fuel gas and the gas injection device 48.

  A gas supply electromagnetic valve 52 is provided at the inlet of the gas injection device 48 of the gas supply pipe 50 and is controlled to open and close by a control signal from a fuel control device 60 (including the ignition timing control unit 18 in FIG. 1) described later. The gas supply time, that is, the gas flow rate is adjusted. 54 is an ignition device for injecting pilot fuel from a pilot fuel injection valve into a sub chamber (not shown) when starting the gas engine and igniting the torch to promote the combustion of the lean mixed gas on the main combustion chamber side. is there.

  During the operation of the gas engine having such a configuration, the torch ignition is performed in the ignition device 54, and the gas valve (not shown) is opened so that the fuel gas in the fuel gas tank (not shown) is supplied to the gas pressure adjusting device (not shown). ) And the pressure is adjusted and supplied to the gas injection device 48. Then, by opening the gas supply electromagnetic valve 52, gas is injected into the air in the intake pipe 44 and mixed with air, and pre-combustion is performed by the injection flame from the ignition device 54 together with the opening of the intake valve 38, The fuel is introduced into the combustion chamber 36 and burned to form a predetermined combustion cycle.

  Reference numeral 12 denotes a cylinder pressure detector that detects the gas pressure in the combustion chamber 36 of the gas engine, that is, the cylinder pressure, and 56 is a crank angle detector that detects the crank angle of the crankshaft 46. Reference numeral 14 denotes a combustion diagnostic device (combustion diagnostic device 14 in FIG. 1), which includes an early ignition determination means 58 and a combustion diagnostic unit 60. The combustion diagnosis unit 60 uses the crank angle detection signal from the crank angle detector 56 on the basis of the pre-ignition determination means 58 and the in-cylinder pressure detection value of the in-cylinder pressure detector 12 to assist in the combustion chamber 36. The combustion state in is diagnosed.

  A combustion control device 70 receives a diagnosis result signal from the combustion diagnosis unit 60 and controls the operation of the ignition device 54 while shutting off or opening / closing the gas supply electromagnetic valve 52 based on the diagnosis result signal. Reference numeral 62 denotes a display device that displays a diagnosis result in the combustion diagnosis unit 60. In addition, an alarm device that issues an alarm based on the combustion diagnosis result may be connected.

  In the combustion diagnostic apparatus configured as described above, the pre-ignition determination means 58 performs pre-ignition based on the in-cylinder pressure detection value of the in-cylinder pressure detector 12 and the crank angle detection signal from the crank angle detector 56. The combustion diagnosis unit 60 determines whether or not there is abnormal combustion, and sends the result to the combustion control device 70 including the ignition timing control unit 18 via the input unit 16 of FIG.

Then, based on the result sent as described above, the combustion control device 70 shuts off or opens / closes the gas supply electromagnetic valve 52, and controls the operation of the ignition device 54 when the pressure is high (H) to ignite. If the timing is delayed (retarded) and the pressure is low (L), the ignition timing is also advanced (advanced), and control is performed as it is without retarding or advancing at normal pressure (N). That is why.
Note that further details of the combustion diagnosis are described in Patent Document 1 described above, and are therefore omitted.

  The above is the apparatus for carrying out the control method when the combustion diagnosis signal of the internal combustion engine of the present invention is abnormal. Next, using the flowchart of the combustion diagnosis method of the internal combustion engine of the present invention shown in FIG. A control method when the signal is abnormal will be described.

  When the process starts in step S10, first, in step S12, instead of the input normality determination signal from the input normality determination unit 22 provided in the input unit 16 of FIG. Periodically issues a data transfer request and detects the response as "input detection". Then, the received result, that is, from the input normality determination unit 22 of the input unit 16, a signal indicating that the input unit 16 is operating normally or is abnormal due to failure, or data sent from the ignition timing control unit 18 Whether or not the input unit 16 is normal is determined based on whether the data is normally sent to the transfer request or there is no response for a certain period of time.

  If the input unit 16 is normal, the process proceeds to the next step S16, and it is determined whether or not the current cylinder pressure exceeds the optimum range. As a result, if it exceeds, in step S20, an ignition timing retardation instruction is sent to the combustion control device 70 shown in FIG. 2 of the internal combustion engine 20 to control the pressure in the cylinder to be low, and then step S24. Proceed to If not, the process proceeds to step S18.

  If the process proceeds to step S18, it is determined whether or not the current in-cylinder pressure is below the optimum range. If the current pressure is below the optimum range, an ignition timing advance instruction is issued in step S22 and Is sent to the combustion control device 70 shown in FIG. 4 and is controlled so as to increase the pressure in the cylinder. If not, the process proceeds to step S24 assuming that the current combustion is in the optimum range and that the ignition timing is neither advanced nor retarded. .

  On the other hand, if the input normality determination unit 22 to the input unit 16 fails and is abnormal in step S14, or if there is no response for a certain time to the data transfer request from the ignition timing control unit 18, the combustion is currently in the optimum range. The combustion control shown in FIG. 2 is controlled so that the ignition timing is not advanced or retarded in the same manner as when a signal of “normal pressure (N)” is sent from the input unit 16. Send to device 70 and finish. In addition, the process of this flowchart is performed for every cycle of the engine 30.

  When the input unit 16 is determined to be abnormal in this way, the ignition timing control unit 18 is forcibly handled in the same manner as when the current pressure in the cylinder is normal, so that neither the retard nor the advance is made. Combustion of an internal combustion engine that can increase the pressure in the cylinder by increasing the combustion and prevent the occurrence of serious troubles such as a gas chamber with a sub chamber, etc. It can be a control method when the diagnostic signal is abnormal.

  According to the present invention, it is possible to provide a combustion diagnostic apparatus that can prevent a serious trouble from occurring even if an element constituting the input unit 16 fails.

It is a block diagram for demonstrating the combustion diagnostic apparatus of an internal combustion engine which becomes this invention. It is a block diagram which shows the whole structure of the combustion diagnostic apparatus of the gas engine as an internal combustion engine. It is a flowchart of the combustion diagnostic method of an internal combustion engine which becomes this invention. It is a block diagram for demonstrating the combustion diagnostic apparatus of the conventional internal combustion engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Combustion cylinder 12 Cylinder pressure detector 14 Combustion diagnostic apparatus 16 Input part 18 Ignition timing control part 20 Internal combustion engine 22 Input normality determination part

Claims (1)

Based on the in-cylinder pressure detection value detected by the in-cylinder pressure detector, the combustion diagnosis device diagnoses the combustion state in the cylinder, and converts the diagnosis result into a digital signal at an input unit including an analog / digital conversion unit. When it is sent to the ignition timing control unit, and the detected pressure value in the cylinder indicates low pressure (L) in the cylinder, the ignition timing is advanced (advance) and the pressure high (H) is indicated. In the combustion diagnosis method for a combustion internal combustion engine, which is slow (retarded) in case and normal pressure (N) is left as it is, when an abnormality occurs in the input portion, the combustion diagnosis signal of the internal combustion engine is abnormal. A control method,
When a signal indicating an abnormality is given to the input unit with a failure self-diagnosis function, or when there is no response for a predetermined time with respect to a data transfer request periodically issued from the ignition timing control unit, Combustion diagnosis signal for an internal combustion engine characterized in that an input unit is determined to be abnormal and the ignition timing control unit normalizes the current cylinder pressure so that the ignition timing is neither retarded nor advanced Control method at the time of abnormality.

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