JPS6073031A - Control device for diesel engine - Google Patents

Abstract

PURPOSE:To reduce a vibration or a noise as well as to check the emission of white smoke, by installing a knock sensor for detecting an engine knock and an injection timing control device which makes the injection timing into delayed timing control at a time when knocking happens. CONSTITUTION:A knock sensor 22 detects an engine knock. In time of idling drive, if knocking happens whereby a high level signal (b) is generated out of the knock sensor 22, a high level signal (h) is fed to an input terminal one side of an AND circuit 25 from a NAND circuit 32, while a high level signal (c) is fed to an input terminal on the other from a knock discrimination circuit 24. In consequence, a high level (d) is outputted from the AND circuit 25 whereby a command signal emitted out of an injection timing control circuit 26 is turned to ON. With this constitution, an injection pump actuator 15 is actuated, making the fuel injection timing into delayed timing control. Thus the reduction of a vibration or a noise and the check of white smoke emission stand together.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an operation control device for a diesel engine mounted on an automobile or the like.

(b) Conventional diesel engines have a high rate of increase in combustion pressure upon ignition, and therefore generate significant vibration and noise during light load operation, especially during idling.

A valve is provided, and this throttle valve is closed during idling to reduce the amount of intake air, thereby reducing the rate of increase in combustion pressure. , devices that can suppress vibration and noise have been developed. However, if the throttle valve is throttled too much, ignition will be incomplete, resulting in an increase in the amount of unburned gas discharged, resulting in disadvantages such as significant generation of white smoke, knocking, and increased vibration. Therefore, in order to achieve both vibration and noise reduction and white smoke suppression using this type of system, the throttle star of the throttle valve must be delicately adjusted, and highly accurate valve opening/closing control is required. becomes. Furthermore, even if perfect adjustment is performed under specific conditions, the amount of intake air fluctuates in response to changes in outside air temperature, atmospheric pressure, etc., making it difficult to always perform appropriate control.

By the way, as a prior art of this type of method, Japanese Patent Application Laid-open No. 1983-
As shown in No. 77132, in a diesel engine provided with a throttle valve in the intake pipe.

There is a device that detects the magnitude of engine vibration and controls the opening degree of a throttle valve so as to suppress the vibration level to a preset magnitude. In this case, since the opening degree of the throttle valve can be converged near the optimum balance point, vibration and noise can be reduced and white smoke can be suppressed to some extent. However, in diesel engines, output is controlled in part by fuel system control, and simply controlling the intake air amount by adjusting the opening of the throttle valve will quickly suppress knocking and reduce vibration and noise. The problem is that it is difficult to end it quickly.

(c) Purpose The present invention was made with attention to such circumstances,
There is no need for delicate adjustments.''Second, the control has good responsiveness.
One object of the present invention is to provide an operation control device for a diesel engine that can easily and reliably achieve both reduction of vibration and noise and suppression of white smoke generation.

(D) Structure In order to achieve the above object, the present invention includes a non-knock sensor that detects knocking, and a case where the knock sensor outputs a signal indicating that non-knock has occurred during a predetermined light load operation including idling. The present invention is characterized in that the fuel injection device further comprises injection timing control means for retarding the fuel injection timing.

(e) Examples Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

1 in Figure 1 is the diesel engine itself installed in the car. The diesel engine main body 1 is a normal one having a combustion chamber 4 in the L force of a piston 3 housed in a cylinder 2. In this combustion chamber 4, an injection nozzle 6 connected to a fuel injection pump 5 and a glow Plug 7 is temporarily installed.

In addition, an intake pipe 11 is connected to an intake boat 9 that communicates with the combustion chamber 4 via an intake valve 8, and a main throttle is provided in the middle of the intake pipe 11, which is kept fully open at all times and is fully closed only during idling. A valve 12 is provided. Further, an intake bypass passage 13 is provided in parallel to a portion of the intake pipe 11 where the main throttle valve 12 is interposed, and an intake bypass throttle valve 14 is provided in this intake/wooden cross passage 13. Further, the fuel injection pump 5
is equipped with an injection pump actuator 15 for changing the position of a cam for regulating injection timing.

Then, the glow plug 7, the intake bypass throttle gop 14, and the injection pump actuator 15 are connected to the second
It is controlled by an operation control device 16 shown in the figure. To be more specific, the operation control device ξ16 includes an injection timing control unit 7 for controlling the injection timing of the fuel fuel 1, a glow plug control unit 18 for controlling energization to the glow plug 7, and a throttle valve control means 19 for controlling the operation of the intake bypass throttle valve 14. The injection timing control means 17 uses an idle sensor 21 provided in the fuel injection pump 5 to detect non-king of the engine t 6 /
an idle detection circuit 23 that is provided in conjunction with the hi-level sensor 22 and outputs a hi-level signal a when it detects that the engine is in an idling state based on a signal from the idling sensor 21; Knock determination circuit 2 which outputs a hi level signal sound when it receives both the level signal a and the hi level signal outputted from the non-knock sensor 22 when knocking occurs.
4, and an AND circuit 25 that outputs a high level signal d when the high level signals c and h are input to the input terminals 1 and 1, and a high level signal 13-d from this AND circuit 25.
The injection timing control circuit 26 operates the injection pump actuator 15 to retard the injection timing by a predetermined angle when the injection pump is released. Idle sensor 2
Reference numeral 1 denotes a swifter that changes νJ according to the operation of the control lever of the fuel injection pump 5, etc. Further, the knock sensor 22 is a so-called vibration type sensor configured to switch from a low level output state to a high level output state f/ when the combustion vibration exceeds a certain value.
For example, it is fixed to the shilling block 2a. - The power and glow plug control means 18 includes a smoke determination circuit 28 which outputs a hi level signal f when it receives both the hi level signal e outputted from the smoke sensor 27 and the hi level signal a; Each hl level signal q, f,
When either one of C is received, the high level signal g
The OR circuit 29 that outputs
The glow plug 7 is provided with a glow controller 31 that energizes the glow plug 7 when the level signal output state is switched to the hi level signal output state. The smoke sensor 27 is maintained in a low level signal output state when the amount of white smoke discharged from the combustion chamber 4 is above the set value, and outputs a high level signal e when the amount of white smoke discharged from the combustion chamber 4 is less than the set value. This sensor is arranged in the middle of the exhaust pipe 10. Note that the signal output from the smoke determination circuit 28 is passed through the NAND circuit 32 to the AND
It is also supplied to one input terminal of the circuit 25. On the other hand, the throttle valve control means 19 is provided in association with the negative pressure sensor 33 for detecting the negative pressure in the intake pipe 11, and includes a negative pressure feedback control circuit 34 incorporating the following control program. It becomes. That is, this negative pressure feedback control circuit 34 receives the high level signal S3a signal from the idle determination circuit 23, and also outputs the smoke I'l signal.
When the 1ow level signal is output from the l constant circuit 28, the intake bypass throttle valve 14 is opened and closed based on the signal from the negative pressure sensor 33 to control the intake negative pressure to a predetermined value. Specifically, 110 intake bypass throttle 'Jj
The substantial opening degree of the intake bypass throttle 1r14 is adjusted by applying a pulse force (d) to the stencil motor 14a of the f14 and changing the duty ratio of the pulse signal. If the idle determination circuit 23 outputs the h level signal a and the smoke determination circuit 28 also outputs the high level signal f, it is determined whether the signal from the negative pressure sensor 33 is Regardless + iii Intake bypass throttle rib 1゛1
4 is controlled to the opening side. On the other hand, the Ihe signal from the idle restraint circuit 23 becomes a low level signal!
When i'J is changed, the operation of the negative pressure flow control circuit 34 is stopped and the intake bypass throttle cell 14 is
The opening/closing control is stopped. In addition,
In this embodiment, the idle detection circuit 23, the knock determination circuit 24, the AND circuit 25, the injection timing control circuit 26, the smoke determination circuit 28, the OR circuit 29, the NAND AND circuit, The feedback control circuit 34 and one controller 35
It is unitized as a unit.

Next, the operation of this embodiment will be explained.

During normal operation other than idle link, main throttle valve 1
2 is fully opened, the intake bypass throttle valve 14 is held in a stopped state, and no special control is performed. On the other hand, during idling, the first throttle valve 12 is fully opened and, as shown in FIG. 3, the signal from the idle sensor 21 is switched from OFF to ON, for example. As a result, a high level signal a is outputted from the idle detection circuit 23, which operates based on the signal from the idle sensor 18, to the knock determination circuit 24, the smoke determination circuit 28, and the negative pressure foot puncture control circuit 34. As a result, the negative pressure feedback control circuit 34 is activated and controls the opening and closing of the intake bypass throttle valve 14 so that the negative pressure in the intake pipe 11 detected by the negative pressure sensor 33 is maintained at a constant negative pressure. At this time, when the white smoke initially emitted from the combustion chamber 4 exceeds the set value and the signal output from the smoke determination circuit 28 changes to the high level signal f, the negative pressure feedback control circuit 34 As a result, the intake bypass throttle valve 14 is controlled to the open side. At the same time, the signal output from the OR circuit 29 is switched to the high level signal g, the glow plug controller 31 is switched on, and the glow plug 7 is energized. Therefore, the ignition temperature in the engine's suction chamber/(as the ignition temperature increases)
- The generation of white smoke is suppressed. When the white smoke generation level becomes less than the set value, the control (11), that is, the control to set the intake bypass throttle valve 14 to the open side and the control to energize the glow plug 7, is stopped. ,
In response to the signal from the negative pressure sensor 33 (execution of normal intake throttle control is resumed. Note that knocking has occurred during this idling operation), when a high level signal is output from the sensor 22. , the knock determination circuit 24 switches from the IOW level signal output state to the hi level signal C output state, and the hi level signal g is output from the OR circuit 29 and the glow plug 7 is energized. Furthermore, when knocking occurs during idling and in an operating range where the smoke determination circuit 28 does not output the hi level signal f, and the knock sensor 22 outputs the hi level signal f, the NAND from the circuit 32 to the AN
A high level signal C is supplied to one input terminal of the D circuit 25, and a high level signal C is supplied from the knock determination circuit 24 to the other input terminal. As a result, the high level signal d is output from the AND circuit 25, and the command signal output from the injection timing control circuit 26 is switched from off to on. As a result, the injection pump actuator 15 is actuated, and the fuel injection timing is corrected to the retard side by a predetermined angle. Therefore, combustion conditions are improved, knocking is suppressed, and vibrations and noise are suppressed without causing white smoke. And when the knocking stops,
The signal supplied from the knock determination circuit 24 to the AND circuit 25 is switched to a low level signal, and the command signal supplied from the injection timing control circuit 26 to the injection pump actuator 15 is turned off, thereby changing the fuel injection timing. is returned to its standard value.

In this embodiment, when white smoke is generated and a high level signal e is output from the smoke determination circuit 28, the glow plug 7 is energized and the intake/hay pass throttle valve 14 is energized.
Since the opening degree is corrected to the open side, the generation of white smoke can be effectively suppressed. Therefore, in this embodiment, h
When the i-level signal e is being output, correction control of the fuel injection timing is not performed.

Note that the non-ignition sensor is of course not limited to the one in the above embodiment, and for example, it may be attached to the entire seat of the bolt to the cylinder to detect combustion vibrations as pressure fluctuations due to strain in the cylinder bolt, or it may be used to detect combustion vibrations as pressure fluctuations due to strain in the cylinder bolt. A pressure type sensor is installed in the seat of the nozzle and detects combustion vibrations as pressure fluctuations via the glow plug, or a pressure sensor is used to directly detect the combustion chamber pressure, or a microphone is used to detect non-stop noise. It may also be a microphone type device designed for detection.

(c) Effects Since the present invention has the following configuration, the following effects can be obtained.

First, it detects non-knocking, which is a direct cause of vibration and noise, and corrects and controls the fuel injection timing to the retarded side to eliminate this knocking, so it is necessary to make subtle adjustments to the throttle valve. Engine vibration and noise can be effectively reduced without any noise, and no control problems will occur even if the outside air temperature or atmospheric pressure fluctuates.

Additionally, when knocking occurs, correcting the fuel injection timing to the retarded side to improve the combustion condition also suppresses the generation of white smoke, which naturally reduces vibration and noise. It is possible to simultaneously suppress white smoke.

Furthermore, if the fuel injection timing is subjected to supplementary IF control, the combustion state can be improved more quickly than when controlling the opening and closing of the throttle valve, so that non-king can be quickly brought to an end. Therefore, control responsiveness can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which 1st IN is a system explanatory diagram, FIG. 2 is a control block 1Δ, and FIG. 3 is a timing diagram showing signal output states. 1...Engine main body 4...Combustion chamber 5...Fuel injection pump 15...Injection pump actuator 16...Operation control device 17...Injection timing control means 21-Idle sensor 221-Non-cooling sensor Agent Patent Attorney Fu Akazawa

Claims (1)

[Claims] A knock sensor that detects non-king, and an injection timing control that retards the fuel injection timing when the knock sensor outputs a signal indicating that knocking has occurred during predetermined light load operation including idling. 1. A diesel engine operation control device comprising: means.