JPS60159349A - Ignition timing controlling method of electrically controlled diesel engine - Google Patents

Abstract

PURPOSE:To prevent any wrong operation from occuring, by judging on whether a peak value of an ignition sensor's output is larger than the setting value or not and, when the peak value is smaller than the said setting one, suspending the feedback control of ignition timing on the basis of the ignition sensor's output. CONSTITUTION:In the case where it is so judged that cooling water temperature by a cooling water sensor 51 is above the setting value and an engine's warm-up is over, at an engine control unit 58, successively whether or not an engine is in its idling state is judged from an accelerator's opening by an accelerator sensor 54 at the ECU58. Next, when YES jusgment is the case, a peak value of an igniction sensor's output, or the output of a peak hold circuit inside the ECU 58 inputting an output signal out of an ignition sensor 56 is read in, whereby that whether the peak value is larger than the setting value oe not is judged. And, in time of YES judgment, i.e., when the output of the ignition sensor 56 is normal, feedback control over the ignition timing based on the ignition sensor's output takes place, but in time of NO judgment, the said feedback control is suspended at once.

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to an ignition timing control method for an electronic i-controlled diesel engine, and in particular, a method for controlling ignition timing in an engine combustion chamber, which is suitable for use in an electronically controlled diesel engine for automobiles equipped with an ignition sensor. This invention relates to an improvement in an ignition timing control method for an electronically controlled diesel engine that performs feedback control of fuel injection timing so that the actual ignition timing detected from the output of an ignition sensor that receives light becomes the required ignition timing. Prior Art] When controlling the fuel injection timing to optimize the exhaust gas purification performance of a diesel engine, especially an automobile diesel engine, an ignition sensor is provided that receives combustion light in the engine combustion chamber, and from the rise of the output of the ignition sensor, It has been proposed to detect the ignition timing and perform feedback control on, for example, the timing 111171111 valve, etc., according to the detection result.According to such feedback control of the fuel injection timing based on the output of the ignition sensor, the fuel It is possible to accurately feedback control the injection timing, but it will not dry out if the tip of the ignition sensor's guide body, which is exposed inside the engine combustion chamber, is dirty or damaged, or the light-receiving element that generates an electrical signal according to the intensity of combustion light. When the amount of light received by the ignition sensor decreases due to deterioration, failure, etc.
As shown in FIG. 1, the detected ignition timing deviates from the correct value, resulting in erroneous detection. Therefore, if the fuel injection timing is feedback-controlled based on this erroneously detected actual ignition timing, the fuel injection timing will be far away from the required injection timing, resulting in deterioration in exhaust gas purification performance, output performance, and fuel efficiency, as well as noise. There was a problem that the amount increased. OBJECT OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, in which the fuel injection timing is erroneously feedback-controlled based on the actual ignition timing that is erroneously detected when the ignition sensor is abnormal. Therefore, an object of the present invention is to provide an ignition timing control method for an electronic III-III diesel engine in which the fuel injection timing does not deviate far from the required injection timing.

Arrangement 1 of the Invention The present invention provides an electronic lll11 that feedback-controls the fuel injection timing so that the actual ignition timing detected from the output of an ignition sensor that receives combustion light in the engine combustion chamber becomes number * ignition timing. In the ignition timing control method for a diesel engine, as summarized in FIG. A procedure for determining whether the peak value of the ignition sensor output is greater than a set value, and when the peak value is greater than the set value,
The method includes a step of executing feedback control of fuel injection timing based on the ignition sensor output, and a step of canceling the feedback control of the fuel injection timing based on the ignition sensor output when the peak value is smaller than a set value. According to
The above objective has been achieved. [Operation of the invention] The present invention provides a method for determining the amount of light received by the ignition sensor and the peak value V pe '
This was done based on the fact that there is a good correlation between ak and ak as shown in Figure 3, and a decrease in the amount of light received by the ignition sensor can be detected by the peak value V peak. In this state, when the peak value V peak of the ignition sensor output is smaller than the set value, the feedback control of the fuel injection timing based on the ignition sensor output is stopped. The fuel injection timing will not be erroneously feedback-controlled based on the timing, and therefore the fuel injection timing will not deviate from the desired injection timing. Therefore, there will be no deterioration in exhaust gas purification performance, output performance, or fuel efficiency, or an increase in noise. In addition, an embodiment of an electronic diesel engine for automobiles equipped with an ignition sensor will be described in detail.This embodiment is shown in FIG. a drive shaft 14 fixed to the drive shaft 14, a feed pump 16 for pumping fuel (FIG. 4 shows a 90° expanded state), a fuel pressure 11111 valve 18 for adjusting the fuel supply pressure. , for detecting the rotation speed Ne of the diesel engine 10 by measuring the time required for the drive shaft 14 to rotate by a predetermined crank angle from the rotational displacement of the IC gear 20 fixed to the drive shaft 14, for example. A rotation speed sensor 22 consisting of an electromagnetic pickup, a roller ring 24 for driving the pump plunger 40 in cooperation with a face cam 23, and a timer piston 26 (the first 4), a timing control valve 28 for controlling the fuel injection timing by controlling the position of the timer piston 26, and a timing control valve 28 for controlling the timing for releasing fuel from the pump plunger 40. A spill ring 32, a spill actuator 34 for controlling the fuel injection amount by controlling the position of the spill ring 32, a spill actuator 34 for detecting the position of the spill ring 32 from the displacement of the plunger 34A of the spill actuator 34, One spill position sensor 36 consisting of a variable inductance sensor, a fuel cut solenoid (hereinafter referred to as FC) 38 for cutting fuel when the engine is stopped, and a delivery valve 42 for preventing backflow or dripping of fuel. An injection pump 12, an injection nozzle 44 for injecting the fuel discharged from the delivery valve 42 of the fuel injection pump 12 into the combustion chamber 10A of the diesel engine 10, and an intake pipe 46 for injecting the fuel into the combustion chamber 10A of the diesel engine 10. An intake air temperature sensor 50 for detecting air temperature and a diesel engine 10
A water temperature sensor 51 for detecting the engine cooling water temperature 1-HW, which is disposed in the cylinder block 10B of top dead center sensor 5
2, an accelerator sensor 54 for detecting the depression/depression angle (hereinafter referred to as accelerator opening degree) of the accelerator pedal 53 operated by the driver, and an ignition sensor 54 for detecting the combustion light in the engine combustion OA. The required injection timing and the required injection amount are determined by the sensor 56, the accelerator opening Accp detected from the output of the accelerator sensor 54, the engine rotation speed Ne detected from the output of the rotation speed sensor 22, etc., and the required injection amount is determined from the fuel injection pump 12. , and an electronic control unit (hereinafter referred to as ECU) 58 that controls the timing control valve 28, spill actuator 34, etc. so that the required injection amount of fuel is injected at the required injection timing. The ignition sensor 56 is installed in the cylinder head 10C of the diesel engine 10, as shown in detail in FIGS. 5 and 6.
a case 56A shared with, for example, a glow plug case; a light guide 56B made of, for example, quartz glass, inserted into the center of the case 56A, for transmitting combustion light; and the light guide The light receiving element 56C-, which is made of, for example, a silicon photodiode, detects the light transmitted by the light receiving element 56B and converts it into an electric signal. As shown in detail in FIG. 7, the ECU 38 includes a central processing unit (hereinafter referred to as CPLJ) 58A for performing various calculation processes, and a read-only memory (hereinafter referred to as ROM) for storing control programs and various data. ) 58B, and a random access memory (hereinafter referred to as RA) for temporarily storing calculation data etc. in the CPU 58A.
(referred to as M) 58C, a clock generation circuit 58D,
The output of the spill position sensor 36 is input via a buffer 58E, the output of the intake temperature sensor 50 is input via a buffer 58F, the output of the water temperature sensor 51 is input via a buffer 58G, and the output is input via a buffer 58H. to a multiplexer (hereinafter referred to as MPX) 58 for sequentially taking in the output of the accelerator sensor 54, the peak hold value of the output of the ignition sensor 56 inputted via the peak hold circuit 581 and the amplifier 58J; Analog-to-digital converter (hereinafter referred to as A/D) for converting the output analog signal into a digital signal
converter) 58L, and an input/output port (hereinafter referred to as I
a waveform shaping circuit 58N for shaping the output of the ignition sensor 56 and directly loading it into the CPU 58A; and a waveform shaping circuit 58N for shaping the output of the rotational speed sensor 22 and loading it directly into the CPU 58A. A circuit 58P, a waveform shaping circuit 58Q for waveform shaping the output of the top dead center sensor 52 and directly importing it into the CPU 58A, and driving the timing control valve 28 in accordance with the calculation results in the CPU 58A. drive circuit 58R and a digital-to-analog converter (hereinafter referred to as D/
The output of the CPU 58A converted into an analog signal by the A converter 588 and the spill position sensor 36
a serve amplifier '58 for driving the spill actuator 34 according to the deviation from the output spill position signal;
T and drive circuit 58U, and a common bus 58V for connecting the respective component devices and transferring data and instructions;
It consists of The operation of the embodiment will be explained below. Ignition timing control in this embodiment is executed according to a flowchart as shown in FIG. That is, first step 110
Then, it is determined whether the engine cooling water temperature TI-IW detected from the output of the water temperature sensor 51 is equal to or higher than a predetermined value, for example, 80°C. When the determination result is positive, that is, when it is determined that engine warm-up has been completed, the process proceeds to step 112, and it is determined whether or not the engine is in an idling state, for example, from the accelerator opening degree Accρ output from the accelerator sensor 54. do. If the determination result is positive, that is, if it is determined that the engine is in an idle state after warming up, the process proceeds to step 114, and the ignition sensor output peak value V peak of the output of the peak hold circuit 581 is read. . After step 114N, the process proceeds to step 116, where it is determined whether the peak @V peak at that time is larger than the set value. If the determination result is positive, that is, if the output of the ignition sensor 56 is determined to be normal, and if the determination result of step 110 or 112 is negative, the fuel based on the ignition sensor output Performs feedback control of injection timing. Specifically, first, in step 118, it is determined whether or not the time for determining the drive timing of the timing control valve 28, for example, 50 II 1 second, has elapsed. If the determination result is positive, the process advances to step 120, and the rotation speed sensor 2
Expresses the engine load, which is determined from the engine rotation speed Ne determined from the two outputs and the output of the accelerator sensor 54 (reads the accelerator opening degree A C00. Next, step 12
Proceeding to step 2, the required ignition timing Tflre is determined in accordance with the engine rotational speed Ne and the accelerator opening Acap using, for example, a two-dimensional map stored in advance in the ROM 58B. Next, the process proceeds to step 124, where the actual ignition timing Tl1re' is detected, for example, from the rising edge of the waveform shaping signal output from the ignition sensor 56. Next, the process proceeds to step 126, and the difference ΔTfire between the requester's ignition timing Tfire and the actual ignition timing T'fire is calculated using the following equation. ΔT fire −T fire −T′ fire
(1) Next, the process proceeds to step 128, where the proportional term D(11) and the integral term D(i) of the drive □uty signal of the timing control valve 28 are determined as a function of the difference ΔTrire, as shown in the following equation. D(p)=f(ΔT fire) ・−(2)D(i)
−o(ΔT fire)−(3) then step 130
Then, as shown in the following equation, the duty control signal is calculated as the sum of the proportional term D(p) and the integrated value ΣD(1) of the integral term. Duty −D(p)+ΣD(i)・(4) After step 130 is completed, or if the determination result in step 116 or 118 is negative, step 132
Then, an output corresponding to the □uty control signal at that time is given to the timing control valve 28 to drive the timer piston 26 and control the fuel injection timing. In this way, when the determination result in step 116 is positive, that is, the peak value V pe of the ignition sensor 56 output
When the ignition sensor is normal and ak is larger than the set value, the timing control valve 28 is feedback-controlled in accordance with the actual ignition timing Trire' determined by the ignition sensor 56.
It is possible to obtain a fuel injection timing that matches the required ignition timing Tfire, which is determined according to the engine rotational speed Ne and the accelerator opening AOCD <engine load. On the other hand, if the determination result in step 116 is negative, that is, the peak value V peak of the ignition sensor 56 output is less than the set value, and the tip surface of the light guide 56B of the ignition sensor 56 is dirty, damaged, or When it is determined that the amount of light received is decreasing due to deterioration or failure of the light receiving element 56C, the ignition sensor 56
Since the feedback control of the fuel injection timing based on the output is stopped, the fuel injection timing will not be erroneously feedback-controlled based on the erroneously detected actual ignition timing. There is no possibility that the exhaust gas purification performance, output performance, and fuel efficiency performance will deteriorate or noise will increase due to the deviation from the value. In this embodiment, when the ignition sensor is abnormal, the previous fuel injection timing is maintained, so the control is simple. Note that the ignition timing control method when the ignition sensor is abnormal is not limited to this, and for example, oven loop control may be performed using the required injection timing 7rirct determined from the engine rotation speed Ne and the accelerator opening Accp (engine load). It is possible. In this case, even if the engine operating state changes, it is possible to respond appropriately. Effects of the Invention As explained above, according to the present invention, the fuel injection timing will not deviate drastically from the required value when the ignition sensor is abnormal, and the exhaust gas purification performance, output performance, and fuel efficiency performance will deteriorate, and noise will be reduced. It has the excellent effect of not increasing the amount of water.

[Brief explanation of drawings]

FIG. 1 is a miniature diagram showing an example of the relationship between the amount of light received by the sensor and the ignition timing detection delay in the ignition sensor, and FIG. 2 is a flowchart showing the gist of the ignition timing control method for an electronically controlled diesel engine according to the present invention. Figure 3' is a diagram showing an example of the relationship between the amount of light received by the ignition sensor and the peak value of the output of the ignition sensor for detailed explanation of the present invention, and Figure 4 is a diagram showing an example of the relationship between the amount of light received by the ignition sensor and the peak value of the output of the ignition sensor. FIG. 5 is an enlarged sectional view showing the configuration of the ignition sensor used in the embodiment; FIG. Similarly, FIG. 7 is an enlarged sectional view showing the state of installation of the ignition sensor in the engine, FIG. 7 is a block diagram showing the configuration of the electronic control unit used in the above embodiment, and FIG. 11 is a flowchart showing the main parts of a routine for controlling timing. 10...Diesel engine, 12...Fuel injection pump, 26...Timer piston, 28...Timing control valve, 40...Bon plunger, 44...Injection nozzle, 51...Water temperature Sensor, 53... Accelerator pedal, 54... Accelerator sensor, 56... Ignition sensor, 58... Electronic control unit (ECLJ), 58I...
・Peak hold circuit, 58J...amplifier, HW...engine cooling water temperature, A ccp...accelerator opening, V peak...ignition sensor output peak value, K...
Setting value, 7fire...required ignition timing, 7'flre...actual ignition timing. Agent Takaya Ron (and 1 other person) Figure 1 Figure 3 1 name of the rainbow! c%) Figure 2 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] (1) Ignition timing control method for an electronically controlled diesel engine in which fuel injection timing is feedback-controlled so that the actual ignition timing detected from the output of an ignition sensor that receives combustion light in the engine combustion chamber becomes the required ignition timing. , the procedure for determining whether the engine is in an idling state after warming up, and when the engine is in an idling state after warming up, determining whether the peak value of the ignition sensor output is greater than a set value. and when the peak value is larger than the set value, feedback control of the fuel injection timing based on the ignition sensor output is executed (and when the peak value is smaller than the set value, the ignition sensor 1. A method for controlling ignition timing of an electronically controlled diesel engine, the method comprising: ceasing feedback control of fuel injection FRwJ based on output.