JPS60162034A - Fuel injection quantity control method of electronic control diesel engine - Google Patents

Abstract

PURPOSE:To precisely control both fuel injection quantity and fuel injection timing according to temperature inside a combustion chamber without any detriment to the reliability of an engine by precisely and quickly detecting temperature inside the combustion chamber. CONSTITUTION:A fuel injection system consists of an ignition sensor 56, that is, a means for receiving combustion light inside an engine combustion chamber 10a, an electronic control unit which processes data on accelerator opening ACCP and engine rpm Ne and controls both a timing control valve 28 and a spill actuator 34 so as to inject demanded quantity of fuel from a fuel injection pump 12 at a demanded fuel injection timing. An analog-to-digital conversion valve ADTC of the output, namely, the quantity of light received by a photoelectron multiplying tube and a combustion chamber temperature Tc have a good mutual relation therebetween and if an attention is paid to such relation, temperature inside the combustion chamber can be derived from the output of the ignition sensor. The temperature inside the combustion chamber may be determined precisely and quickly and based on such information, fuel injection quantity and/or fuel injection timing may be controlled precisely so that the reliability of an engine may free from any detriment.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fuel injection control method for an electronically controlled diesel engine, and particularly to a fuel injection control method suitable for use in an electronically controlled diesel engine for automobiles, which includes an ignition sensor configured to receive combustion light in an engine combustion chamber. The present invention aims to improve a fuel injection control method for an electronically controlled diesel engine in which the amount of fuel injection 9A and/or the fuel injection timing is electronically controlled according to engine operating conditions including at least engine speed and engine load.

[Prior art 1] In recent years, with the development of electronic control technology, especially digital ILD control technology, so-called electronically controlled diesel engines, in which the positions of the timer piston and spill ring of the fuel injection pump are electronically controlled, have been put into practical use. There is. This electronically controlled diesel engine has the feature that it is possible to strictly control fuel injection suitability and fuel injection timing, but the fuel injection pump is composed of many parts, including a spill ring, plunger, Each part spring,
Due to changes in the spill position sensor, spill actuator, etc. over time and product variations, variations occur in the fuel injection valve. Also, in engines equipped with a turbocharger,
Due to variations in the turbocharger itself and variations in the device that increases or decreases fuel depending on boost pressure, fuel
Variations in ti occur. Due to such variations in the amount of fuel injected by the fuel injection pump and turbocharger, the temperature in the engine combustion chamber also varies, for example, when the fuel injection rate is too high.
1@Copper If the timing becomes overadvanced, the combustion chamber temperature will rise above the upper limit value, and there is a risk that the engine will be damaged due to glow plug burnout, etc. In addition, if the combustion chamber temperature falls below the lower limit, sweat reduction will not be performed smoothly,
This poses a problem in that the thermal efficiency of the engine may be reduced. In order to solve these problems, the combustion chamber temperature is constantly monitored by a temperature sensor, and when the temperature detected by the temperature sensor exceeds the set concentration, the fuel injection amount is reduced or the fuel injection timing is adjusted. It may be possible to prevent the combustion chamber humidity from exceeding the limit value by shifting the IF to the angle side, but if a thermocouple, for example, is used as the temperature sensor, the combustion 7? ! The temperature detection accuracy is very poor, and accurate temperature detection is not possible. In addition, because the response is very slow, using the concentration detected by a thermocouple to control the fuel injection rate and fuel injection timing has problems such as poor engine reliability. Ta. [Object of the Invention] The present invention has been made to solve the above-mentioned conventional problems, and it is possible to detect the combustion chamber temperature of an engine with high accuracy and quickly, thereby preventing damage to the reliability of the engine. An object of the present invention is to provide a fuel injection control method for an electronically controlled diesel engine that can accurately control the fuel injection amount and fuel injection timing according to the combustion chamber temperature without causing the combustion chamber temperature to increase. DESCRIPTION OF THE INVENTION The present invention electronically controls fuel inclination and/or fuel injection timing in accordance with engine operating conditions including at least engine speed and engine load. Electronically controlled diesel engine fuel injection control till:/j
In the law, the summary is shown in Figure 1. As shown in 1, the procedure for calculating the combustion chamber temperature from the output of an oversized sensor designed to receive combustion light in the engine combustion chamber, and the procedure for calculating the combustion chamber temperature according to the claimed combustion chamber temperature. Adjust fuel injection suitability and/or fuel injection timing
The above object is achieved by including the following steps. Further, in an embodiment of the present invention, when determining the combustion chamber temperature from the ignition sensor output, the idle state is set at a set period li.
The ignition sensor output during continuous TC is stored as a reference output corresponding to reference combustion chamber leakage, and the combustion chamber temperature is calculated from the difference between the reference output and the ignition sensor output. Regardless of changes or variations in sensor output over time,
This allows the combustion chamber temperature to be detected with high accuracy. Alternatively, in another embodiment of the present invention, when controlling the fuel opening and opening and/or the fuel injection timing according to the combustion chamber temperature, when the combustion chamber temperature is higher than the upper limit value, the fuel injection amount is When the combustion chamber temperature is lower than the limit value, the fuel injection timing is decreased and the fuel injection timing is advanced. This ensures that the room temperature is maintained within the set range.

[Action of the invention]

The present invention provides an ignition sensor output received by, for example, a photomultiplier tube, that is, an output of an ignition sensor, which is a digital converter of the light received by a photomultiplier tube.
We were pleased to find that there was a good correlation between C and the combustion chamber temperature Tc as shown in Figure 2, and we decided to calculate the combustion chamber temperature from the output of the ignition sensor. , the temperature of the combustion chamber can be set accurately and quickly. Also, fuel is injected according to the combustion chamber temperature determined from the output of the ignition sensor! )IfJ, and/' or fuel injection timing to 1
Since bII all is configured, the fuel injection μ and the fuel injection timing can be accurately controlled according to the combustion chamber temperature without impairing the reliability of the engine. [Example j] Referring to the following, the fuel injection control system according to the present invention will be described below.
Detailed explanation of an example of an electronically controlled diesel engine for transportation vehicles equipped with an ignition sensor in which the /'j method is adopted 4
Ru. As shown in FIG. 3, this embodiment includes a drive shaft 14 that rotates in conjunction with the rotation i of the output shaft of the diesel engine 10, and a feed pump 16 fixed to the drive shaft 14 for pumping fuel. (Fig. 3 shows the state in which it is unfolded by 90 inches). The fuel pressure adjustment valve 18 for adjusting the fuel supply pressure, and the rotational displacement of the gear 20 fixed to the drive shaft 14 cause the drive shaft 14 to reach a predetermined crank position. Only the angle (
(b) A rotation speed sensor 22 made of, for example, an electromagnetic swing knob, and a face cam 2 for measuring the time required for rotation and detecting the rotation speed Ne of the diesel engine 10.
3 to drive the C pump plunger 40.
- The crank 24 controls the rotational position of the roller ring 24.
ll-! timer piston 26 (90 in Fig. 3)
The timing control piece 28 is used to control the fuel injection timing by controlling the position of the tie 7 piston 26 (the timing control piece 28 is used to control the timing of fuel release from the pump plunger 40). A spill ring 32, a spill actuator 34 for controlling fuel injection by changing the position of the spill ring 32, and a plunger 3 of the spill actuator 34.
4. A spill position sensor 36, for example, consisting of a variable inductance sensor, is used to detect the position of the spill ring 32 from the displacement of A, and a fuel cut solenoid, hereinafter referred to as FCV, is used to cut off fuel when the engine is stopped.
8 and a fuel injection bonzo 12 having a delivery valve 42 for preventing backflow or dripping of fuel; and a fuel discharged from the delivery valve 42 of the fuel injection pump 12 into the combustion chamber 10A of the diesel engine 10. an intake air temperature sensor 50 for detecting the temperature of intake air taken in through the intake front 46, and a diesel engine 10.
A water temperature sensor 51 for detecting engine cooling water 'lkn-l-HW, which is disposed in the cylinder block 1013 of an accelerator sensor 54 for detecting the depression angle of the accelerator pedal 53 operated by the driver (hereinafter referred to as accelerator opening degree); The required injection timing and the required injection amount are determined based on the ignition sensor 56 for receiving combustion light, the accelerator expansion ACC11 detected from the output of the accelerator sensor 54, the engine rotation speed Ne detected from the output of the first rotation speed sensor 22, etc. An electronic control unit (hereinafter referred to as ECU) controls the timing control valve 28, spill actuator 34, etc. so that the fuel liar 12 injects the required injection amount of fuel at the desired injection timing. ) 58. The ignition sensor 56 is connected to the cylinder block IO of the diesel engine 10, as shown in detail in FIGS. 4 and 5.
A case 56A shared with a claw plug case, for example, which is inserted and fixed 8 in C, a light guide 56B made of, for example, quartz glass, inserted into the center of the case b6A, and made of quartz glass, for transmitting combustion light, and the guide. The optical cable 56C is configured to transmit the light transmitted by the body 56B to the input side of the ECU 5B. As shown in detail in FIG. 6, the EC (J58) includes a central processing unit (hereinafter referred to as CPU) 58A for performing each S calculation process, and a read-only unit for storing control programs and various data. A memory (hereinafter referred to as ROM) 58B and a random access memory (hereinafter referred to as R) for temporarily storing calculation data sent to the CPU 58A.
(referred to as AM) 58C, a clock generation circuit 58D,
The output of the spill position sensor 36 is inputted via a buffer 58E, the output of the intake temperature sensor 50 is inputted via a buffer 58F, the output of the water temperature sensor 51 is inputted via a buffer 58G, and the output is inputted via a buffer 58H. A multi'plexer (hereinafter referred to as "multiplexer") for sequentially taking in the input output of the accelerator sensor 54, the amount of light received by the ignition sensor 56 via the photomultiplier tube 581 and amplifier 58J connected to the optical cable 56G, etc. an analog-to-digital converter (hereinafter referred to as an A/D converter) 58L for converting an analog signal outputted to the MPX 58 into a digital signal;
An input/output boat (hereinafter referred to as 110 boat) 58 for inputting the output of the A/D converter 58L to the CPU 58A.
M, a waveform shaping circuit 58P for shaping the waveform of the stone sensor 56 output input via a light receiving element 58N, which is made of, for example, a silicon photodiode and connected to the optical cable 56C, and inputting the waveform into the CPU 58A; The CPU 58 shapes the waveform of the rotation speed sensor 22 output.
A waveform shaping circuit 58Q for directly importing the output into the CPU 58A, a waveform shaping circuit 58R for shaping the waveform of the top dead center sensor 52 output and directly importing it into the CPU 58A, and the CPU 58A.
A drive circuit 583 for driving the timing control valve 28 and 58 digital-to-analog converters (hereinafter referred to as D/A converters) convert the signal into an analog signal according to the calculation result in the IC CPU 58A. A serve amplifier 58tJ and a drive circuit 58V for driving the spill actuator 34 are connected to each of the component devices to transfer data and commands according to the deviation from the spill position signal output from the spill position sensor 36. It consists of a common bus 58W for carrying out the operation. The operation of this embodiment will be explained below. Control of fuel@stiffness and fuel injection timing in this embodiment is executed according to a flowchart as shown in FIG. That is, first, in step 110, in the same manner as in the past, the engine rotation speed Ne detected from the output of the rotation speed sensor 22 and the accelerator opening degree representing the engine load detected from the output of the accelerator sensor 54 are determined. According to A ccp, request @ken1iQrin and request injection timing Tfin
I put it on. Next, proceeding to step 112, the photomultiplier tube 58I
The amount of light received by the ignition sensor is photoelectronically amplified by the amplifier 58J, converted into a voltage signal by the amplifier 58J, and A/D-converted in 5 milliseconds by the A/D converter 58L in a separate routine. From the converted value ΔDTC, the combustion chamber temperature Tc is calculated using a map stored in advance in the ROM 58B or a calculation formula corresponding thereto. In this step 112, the A/D conversion value A D 1- of the amount of received light is determined.
When calculating the combustion chamber temperature TO from C, the A/'D conversion value A D when the idle stable state continues for the set period.
T' C is stored as a reference output AD i' Co corresponding to the gutter semi-combusted room temperature melon TCo, and the reference output AD
Difference between TCo and current A/D change #1fiADTC (ADT
The current combustion chamber temperature TO can be calculated from CADTC-o>. Next, proceeding to step 114, the requested combustion chamber temperature 1
It is determined whether or not C is at its upper limit, for example 1000°C. If the determination result is negative, that is, if it is determined that there is a mandrel that lowers the combustion chamber temperature TO, the process proceeds to step 116, and the required jet 1jtJQrin determined in step 110 is changed to, for example, the following By the formula, the predetermined Mid
, 2 wmj/st is set as the control injection amount. (]in 4-Qfin -Q, 2mmj/'5t-
(1) Next, the process proceeds to step 118, in which the required injection timing 1-fin determined in step 110 is retarded by a predetermined value of 0.2° CA, for example, according to the following equation, and the control injection timing is set as the control injection timing. Exit this routine. 'I fin ←Trtn -0,2' CA-(2)
On the other hand, if the determination result in step 114 is positive,
That is, the combustion chamber humidity 1"c is the upper limit mi oo. When it is determined that it is less than 1"C, the process proceeds to step 120, and the combustion chamber temperature -EC is set to the lower limit value, for example 850°C.
It is determined whether it is less than or not. If the determination result is positive, that is, if it is determined that it is necessary to increase the combustion chamber fA fit Tc by L in order to improve the ignitability, the process proceeds to step 122, and the step 1 described above is performed.
For example, the required injection timing Q fin determined in step 10 is expressed as a predetermined value tiF? Only 0.2mmj/st mf[T
The value obtained is called the control injection amount. Qrin +Qrin +0.2mmJ, st...(
3) Next, the process proceeds to step 124, in which the required injection timing Tf:n determined in step 110 is advanced by a predetermined value of 0.2° CA, for example, by the following formula.
This routine can be treated as 11Iiii sword period. 1' in (-1 go own) +Q, 2' CA-(4)-
R, if the judgment result in step 1200 is negative, that is, if the combustion chamber humidity Tc is between the upper limit value and the lower limit value, and it is determined that an appropriate combustion chamber temperature has been determined, the step 1200 described above is performed. The required injection amount Qrin and the required injection timing 14-['ri11 determined in step 110 are set as the ill injection amount and control injection timing, and this routine exits. In this embodiment, when calculating the combustion chamber temperature 1-c from the output of the ignition sensor 56, C is the standard combustion temperature;
Store it as the reference output A D TCo corresponding to Co.
C, the reference output A D HC. and the current ignition sensor output A D −r C (A D
Since the current combustion chamber temperature]C is calculated from 'r CA l') -l-Co), the ignition sensor b6
Even if the output characteristics of the engine change over time and there are variations, it is important to accurately adjust the combustion chamber temperature
Wear. Furthermore, from the output of the ignition sensor 56, the combustion chamber 2M a
The method of calculating T-C is not limited to this, for example, the current combustion chamber temperature - from the current ignition sensor output △DTC.
It is also possible to add 1-c. In addition, in this embodiment, when controlling the fuel injection amount and fuel injection timing according to the combustion chamber temperature Tc, when the combustion chamber temperature Tc is an upper limit value, for example, 1000°C or more, the fuel injection amount Qftn is reduced. At the same time, fuel injection timing T
fin is retarded, while the combustion chamber temperature Tc is lower limit value 850.
When the temperature is below .degree. C., the fuel injection amount Qrin is increased im and the fuel injection timing TriO is advanced, so that the combustion chamber temperature TC can be reliably maintained within the set range. Note that the method of controlling the fuel injection amount and/or fuel injection timing according to the combustion chamber temperature TO is not limited to this, and for example, only the fuel injection amount may be reduced or increased according to the combustion chamber temperature, Alternatively, it is also possible to configure only the fuel injection timing to be retarded or advanced. It is also possible to control only the upper limit value so as not to exceed it. Furthermore, in this embodiment, the diesel engine 1 is already equipped with an ignition sensor 56 for detecting the ignition timing.
Since the present invention is applied to No. 0, there is no need to newly add an ignition sensor 56, and the configuration is simple. Note that the scope of application of the present invention is not limited to this, and by adding a dedicated ignition sensor for detecting combustion chamber humidity, it can also be applied to diesel engines that are not equipped with an ignition timing sensor. ] It is Noh. In addition, in the embodiment, the diesel engine 10
Ignition sensor 56 attached to the cylinder head 10C of
The photomultiplier tube 581 and light receiving element 58N provided in the ECU 38 were connected by an optical cable 56C, but it is also possible to incorporate the photomultiplier tube 58I and the light receiving element 58N in the ignition sensor 56 and omit the C1 optical cable. be.

【Effect of the invention】

As explained above, according to the present invention, the combustion chamber temperature can be detected accurately and quickly. It has the advantage of being able to accurately control the injection timing.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the gist of the fuel injection control method for an electronically controlled diesel engine according to the present invention. FIG. 2 is a diagram showing the correlation between the analog-to-digital conversion value of the ignition sensor's light age and the combustion chamber rotation speed for detailed explanation of the present invention, and FIG. FIG. 4 is a sectional view, including a partial block diagram, showing the overall configuration of an embodiment of an electronic IIJ1ill diesel engine for automobiles equipped with an ignition sensor. Similarly, Fig. 5 is a sectional view showing the state of installation on the cylinder head, and Fig. 6 is a sectional view showing the state of installation on the cylinder head.
The figure is a block diagram that does not show the configuration of the electronic control unit used in the above embodiment. Similarly, FIG. It is a flowchart without showing the main parts. 10... Diesel engine, 12... Fuel injection pump, 22... Rotation speed sensor, N+3... Engine rotation speed, 26... Timer piston, 28...・Timing control valve, 32... Spill ring, 34... Spill actuator, 36... Spill position sensor, 40... Bonzozoranger, 44... Indication nozzle, 54... Accelerator sensor , A CCL+...accelerator opening, 56...ignition sensor, b8...electronic control unit (ECU), 581...
Photomultiplier tube, 58J...Amplifier, 58[...Analog-to-digital (A・''l)) converter, ADT C...Light reception-no-analog-to-digital conversion J@! Value, Tc...combustion chamber temperature, 0fin...required injection tJ4, 1[in...required injection timing. Agent Takayaron (one idiot) Figure 1 Figure 3 Figure 4 Figure 6

Claims (3)

[Claims] (1) In a fuel injection control method for an electronically controlled diesel engine in which the fuel injection amount and/or fuel injection timing is electronically controlled according to engine operating conditions including at least engine speed and engine load, The procedure for calculating the combustion chamber temperature from the output of the ignition sensor that is designed to receive combustion light, and the fuel injection according to the determined combustion chamber humidity! 7. A method for controlling fuel injection for an electronically controlled diesel engine, comprising: a procedure for controlling fuel injection timing. (2) When calculating the combustion chamber temperature from the ignition sensor output, the ignition sensor output when the idling stable state continues for a set period is stored as a reference output corresponding to the reference combustion chamber temperature, and the reference output 2. The fuel injection control method for an electronically controlled diesel engine according to claim 1, wherein the combustion chamber temperature is determined from the difference between the output of the combustion chamber and the output of the ignition sensor. (3) When controlling the fuel injection amount and/or fuel injection timing according to the combustion V temperature, if the combustion chamber temperature is higher than the upper limit value, the fuel injection amount is reduced and the fuel injection is Electronic control according to claim 1, wherein the timing is retarded, and when the combustion chamber temperature is lower than the lower limit, the amount of fuel injection is increased and the fuel injection timing is advanced. Diesel engine fuel injection control method.