JPS59122781A - Electrification control method of glow plug in diesel engine - Google Patents

Abstract

PURPOSE:To both improve ignitionability and reduce white smoke of an engine during the time of its decelerating or dashpot operation, by electrifying a glow plug so as to increase the temperature in a combustion chamber of the engine. CONSTITUTION:In the central processing unit (CPU) (not shown in the drawing) of an electronic control unit (ECU), first in a step 1010, in conditions, for instance, such that an engine speed exceeds a prescribed value with an accelerator pedal in a fully closed condition, it is decided whether or not an engine is in decelerating operation, and if the decision result is NO, a process is advanced to a step 1020. While if the decision result is YES in the preceding step 1010 or 1020, that is, when the engine is in its decelerating or dashpot operation, the process advances to a step 1040, turning on a glow subrelay (not shown in the drawing) and conducting a small electric current to flow in a glow plug 67, thus the temperature in a combustion chamber 10b of the engine increased, improving its ignitionability and reducing the generation of white smoke.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glow plug energization control method for a diesel engine, and in particular, to a method for controlling glow plug energization in a diesel engine, and in particular, to control engine operating conditions suitable for use in an automobile diesel engine equipped with an intake throttle valve and an electronically controlled fuel injection device. The present invention relates to an improvement in a glow plug energization control method for a diesel diesel engine, in which the energization state of the glow plug is controlled according to the energization state of the glow plug.

Generally, in a diesel engine, the fuel supplied to the combustion chamber is controlled by a fuel injection pump that is driven to rotate in synchronization with engine rotation. Using the supply pressure of the feed pump, move the timer to control the timing of the roller ring' (by moving it, the fuel injection u), and change the pressure feed path by encouraging the spill ring with the centrifugal governor. However, in the past, both the timer and the spill ring were mechanically controlled, so precise control of the fuel injection amount was a factor.

On the other hand, in recent years, with the development of electronic control technology, especially digital control technology, attempts have been made to electronically control the fuel injection amount of diesel engines.

According to such electronic control, depending on engine operating conditions such as engine rotation speed and engine load.

It has the feature that it is possible to inject the optimum amount of fuel at the optimum fuel injection timing.

In this type of electronic control, when the vehicle is decelerating, the spill ring of the fuel injection pump is controlled to the point where the fuel is injected, but in reality, the fuel injection pump Due to pump leakage, etc., the fuel injection amount will completely drop to zero (-J).Dad, due to variations in parts and changes over time, the leakage and injection amount will vary greatly.Driving at high altitudes in such conditions Or, in a diesel engine equipped with an intake throttle valve that opens and closes in conjunction with the accelerator pedal for the purpose of completely reducing idle vibration and improving the operating feel when the engine is stopped.

Even when driving on flat ground, the intake pressure decreases due to the intake throttle valve being closed.

The pressure inside the combustion chamber does not rise to the ignition point and the chamber temperature drops one by one, deteriorating the ignitability, resulting in a large amount of leakage and injection being emitted as unburned white smoke, which is a harmful component in the exhaust gas. HC has increased 9, and it may generate strange odors (・U).

Also, in order to prevent engine stall when the vehicle decelerates, is it possible to reduce the fuel injection amount more slowly than the reduction rate of the required injection amount and provide a so-called dashpot function? When I'm driving, or...

In a diesel engine equipped with an intake throttle valve, when the intake throttle valve is closed even when driving on flat ground, the intake pressure decreases and more fuel is injected. As a result, unburned phosphorus is emitted as white smoke.Conventionally, in order to prevent this white smoke, the problem was that the dash pot could not be fully utilized. had.

On the other hand, in recent years, in order to improve the startability of a diesel engine and the idling stability immediately after starting, for example, a glow plug is energized with both a large current and a small current from the time the ignition switch is turned on until the scooter is turned off. Stop applying large current when the starter turns off, and only after the starter turns on.

After a predetermined period of time that varies depending on the engine cooling water temperature has elapsed, the energization of the small ε current is also stopped.

How many methods have been considered for glow plugs in diesel engines?

However, in the past, glow plug energization such as the front color change was performed exclusively at the time of starting the engine and after starting the engine.
Yuponoto was in operation (te(・ended, nothing in particular was being done.

This invention was made in order to eliminate the hard spots in the conventional Qlj@C, and provides a method for controlling energization of a glow plug in a diesel engine that can prevent the generation of white smoke when the dashpot is operating. Let's call it the tth pico.

The present invention relates to a method for controlling energization of a glow plug in a diesel engine, in which the energization state of a glow plug is controlled according to the engine operating state.

As shown in FIG. 1, the above object is achieved by energizing the glow plug to raise the temperature within the engine combustion chamber during deceleration or when the dashpot is in operation.

Also, during the aforementioned deceleration or while the dashpot is operating.

The glow plug is energized with a small current.

The glow plug can be heated for a long time.

Alternatively, during the deceleration or during the engine spot operation, a large current is applied to the trowel plug for a predetermined period of time to enhance the responsive sound. A glow plug energization control method for diesel engines has been adopted. An embodiment of an electronic control device for an automobile diesel engine will be described in detail.

In this embodiment, as shown in FIG. 2, there is a main intake throttle installed in the main intake passage 12 of a diesel engine 10, which rotates in conjunction with, for example, an accelerator pedal 14 operated by the driver. The diesel engine 10 includes a valve 16, a 99F-20 sub-intake throttle, which is disposed in the sub-intake passage 18 that bypasses the main intake passage 12', and which throttles the intake air at idle to reduce idle vibration. 1 drive shaft 24 rotated in conjunction with the rotation of the output shaft of the drive wheel 24;
Feed pump 2 for pumping fuel, fixed to
6 (the second section shows the state rotated by 90 degrees), the fuel pressure adjustment valve 28 for adjusting the fuel supply pressure, and the gear 300 fixed to the drive shaft 24. The diesel engine is set at 100 rotational speed Pt'51 by aiming at the time (6) required to rotate by a certain crank angle.
For example, a rotation speed sensor 32 consisting of an electromagnetic pickup for detecting zero, a roller ring 34 for controlling the injection timing, a timer piston 36 for driving the roller ring 34'a, and a timer piston 36 for driving the roller ring 34'a- a timing control valve 38 for controlling the position of the piston 36; a timer position sensor 40, for example, a variable inductor sensor, for detecting the position of the timer piston 36; a spill ring 42 for controlling the fuel injection amount; A spill actuator 44 consisting of a plunger 44a, a compression spring 44b, a coil 44c and a coil case 44d for operating the spill ring 42-i'M, the plunger 44a
46. A fuel cut solenoid (hereinafter referred to as FCV) for cutting fuel when the engine is stopped, for example, a variable inductance sensor to detect the entire position of the spill ring 42 from the displacement of the spill ring 42.
48-1 A fuel injection pump 22 having a langeer 50 and a delivery nozzle 52, and fuel discharged from the delivery valve 52 of the fuel injection pump 22 into the sub-sludge chamber of the diesel engine 10. ) The injection nozzle 54, the intake pressure sensor 58 for detecting a pressure drop in the intake air taken in through the intake pipe 56, the intake temperature sensor 60 for similarly detecting the temperature of the intake air, and the diesel engine lO. cylinder block 1
0a, a cooling water temperature sensor 62 for detecting the engine cooling water temperature, an accelerator sensor 66 for detecting the entire depression angle of the accelerator pedal 14 (hereinafter referred to as accelerator opening degree), and an engine combustion chamber. The glow plug 67 is heated to 10b' to improve ignitability, and the glow plug 67 is heated to 10b' to improve ignitability. Both current and small current are applied, and after the starter switch is turned off, the current is stopped.
After the starter switch is turned on and a predetermined period of time has elapsed depending on the engine cooling water temperature, the supply of a small current is also stopped, and the engine load detected from the output of the accelerator sensor 66 and the output of the rotational speed sensor 32 are The injection timing and calculated injection amount are determined based on the detected engine rotational speed, the engine cooling water temperature detected from the output of the cooling water temperature sensor 62, etc., and the calculated injection amount f is calculated from the fuel injection pump 22 at the target injection timing. '44 is injected, the timing control valve 38 and the spill actuator 4
An automotive diesel engine lO equipped with an electronic control unit (hereinafter referred to as ECU) 68 that controls 4 etc.
In this electronic control unit, the glow plug 6 is
7, a small current is applied to the engine to raise the temperature inside the combustion chamber of the engine.

In the figure, 35 is a cam plate, and 43 is a tension spring.

The EC068 is shown in detail in FIG.

One example for performing various arithmetic processing is a central processing unit (hereinafter referred to as CPU) consisting of a microcomputer.
69, the output of the cooling water temperature sensor 62 which is input via the buffer 70', the output of the forward bending intake air temperature sensor 60 which is input via the notch 72, and the intake pressure which is input via the buffer 74. The spill position sensor 46 is driven by the sensor drive frequency signal of the sensor 58 output, the accelerator sensor 66 output input via the buffer 76t, and the sensor drive circuit 78 output, and is input via the sensor signal detection circuit 80. Output, also sensor drive circuit 82
A multiplexer 86 is provided to take in the output of the timer position sensor 4o, etc., which is driven by the output sensor driving frequency signal and is input via the sensor signal detection circuit 84, and converts the analog signal output from the multiplexer 86 into a digital signal. An analog-to-digital converter (hereinafter referred to as an A/D converter) 88 for converting into a signal;
An input/output capo 490 for inputting the D converter 88 output 'kc P U 69, an input/output port 96 for inputting the starter switch 92 output etc. input via the buffer 94, and the 'rotational speed sensor' A waveform shaping circuit 98 and a clock generation circuit 102 shape the waveforms of the 32 outputs and input them into the CPU 69.

Random access memory (hereinafter referred to as RAM) including a backup random access memory (hereinafter referred to as RAM) for temporarily storing calculation data etc. in the CPU 69 and for backing up in the event of a power failure.
104 (hereinafter referred to as ROM) 104 for storing control programs and various data, etc.; A drive circuit 112 for driving the glow main relay 116' for passing a large current through the glow sub-relay 114 and the glow plug 67, and a sensing resistor l18 inserted in series in the current supply circuit to the globe 2 plug 67.
A voltage detection circuit 120 for detecting the voltage across the He and feeding it back to the drive circuit 112;
According to the calculation results in the CPU 3O, the drive circuit 122 for driving the timing control valve 38, and also in accordance with the calculation results in the CPU 69.

A drive circuit 124 for driving the FCV 48 and a digital-to-analog converter (hereinafter referred to as a D/A converter)
The CpU 69 converted into an analog signal by 124
It is comprised of a servo amplifier 126 and a drive circuit 128 for driving the spill actuator 44 according to the deviation between the output and the output of the spill position sensor 46. In FIG. 3, 130 is a glow plug resistor for limiting the current flowing to the glow plug 67 when a small current is applied.

The action will be explained below.

The glow plug energization control in this embodiment is executed according to the flowchart shown in FIG. That is, Maemezji EC
In the CPU 69 of the U68, first, step 101
0, the accelerator pedal 14 is in a fully closed state, and the engine rotational speed NE is equal to or higher than a predetermined value, so it is determined whether deceleration is in progress. If the determination result is negative, the process proceeds to step 1020, where a setting is made to increase the fuel injection amount if, for example, the fuel injection amount is increased during deceleration or if the engine speed decreases by more than a predetermined amount. Since the dashpot flag is set, it is determined whether the dashpot is in operation. If the determination result is negative, that is, if the dashpot is not in operation or decelerating, step 1030
Proceed to step 2, and as in the past, connect the glow sub-relay ii4'
This routine ends with i off.

On the other hand, if the determination result in step 1010 or 1020 is positive, that is, if the vehicle is decelerating or the dashpot is operating, the process proceeds to step 1040;
The glow sub-relay 114 is turned on, a small current is applied to the glow 1 lug 67, and the temperature of the engine combustion chamber lOb is increased to improve ignitability, and this routine ends.

In this embodiment, the glow plug sub-relay ii+;t is turned on during deceleration or dashpot operation, so even if the glow plug 67 is heated for a long time, no particular problem will occur. Control is simple. Note that the method of energizing the glow plug 67 during deceleration or during dashpot operation is not limited to this, and responsiveness can also be improved by, for example, turning on the glow main relay 116'i for a predetermined period of time. It is.

In addition, in the above embodiment, both during deceleration and when the dashpot is operating, the glow sub relay ii4 is simply
For example, during deceleration, the amount of flow to the glow 1 lug 67 increases as the engine speed increases.
υ.Also, while the dashpot is in operation, it is also possible to make the amount of electricity supplied to the glow plug 67 larger as the fuel injection amount increases, depending on the fuel injection amount.

In the embodiments described above, the present invention was applied to an automobile diesel engine equipped with an intake throttle valve and an electronically controlled fuel injection device, but the scope of application of the present invention is not limited to this, and the present invention is applied to an electronically controlled fuel injection device. It is obvious that the present invention can be similarly applied to an automobile diesel engine equipped with a fuel injection device or a general diesel engine equipped with other fuel injection devices.

According to the energization described above and the present invention, ignitability during deceleration or dashpot operation is improved, white smoke can be reduced during deceleration or dashpot operation, and harmful components in exhaust gas can be reduced. 1 (has an excellent effect of being able to prevent an increase in C and the generation of off-flavors).

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the gist of a method for controlling energization of a glow plug for a diesel engine according to the present invention, and FIG. 2 shows a method for controlling energization of a glow plug for a diesel engine according to the present invention. FIG. 3 is a sectional view including a partial block diagram showing the configuration of an electronic control unit for an automobile diesel engine according to an embodiment. FIG. FIG. 4, which is a block diagram including a partial circuit diagram, is a flowchart showing a routine for controlling glow plug energization. lO...Diesel engine, 14...Accelerator pedal, 22...Clammeat injection pump, 32...Rotational speed layer sensor, 66...Accelerator sensor, 67...Glow plug, 68... Electronic control unit (ECU). 69... central processing unit) (CPU), 112...
Drive circuit, 114... Glow sub relay, 116...
・Glow main relay, 118...sensing register. 120... Voltage detection circuit, 130... Glow plug resistor. Figure 1 Figure 4

Claims (3)

[Claims] (1) In a diesel engine glow plug energization control method in which the energization state of the glow plug is controlled according to the engine operating state, during deceleration or when the dashpot is operating, the front GB glow plug is energized and the engine is turned on. A method for controlling energization of a diesel engine globe, characterized by increasing the temperature inside a combustion chamber. (2) The method for controlling energization of a glow plug in a diesel engine according to claim 1, wherein a small current is passed through the glow lug during deceleration or during operation of the dashpot. (3) The glow plug energization control method for a diesel engine according to claim 1, wherein a predetermined large current is applied to the glow plug during deceleration or when the dashpot is in operation.