JPS6158970A - Starting accelerator for diesel engine - Google Patents

Abstract

PURPOSE:To make a distinct improvement in a starting characteristic, by installing a fuel regulating device in order to make the specified quantity of fuel into a complete combustion by means of a suction air heater in time of engine starting, and a starting control device controlling a valve device. CONSTITUTION:Inside a bypass passage part 7, there are provided with a throttle valve 8, varying a suction air quantity to some extent, and a suction air heater 23 which makes fuel into combustion for generation of heat. A fuel quantity is regulated by a duty control valve 19. On the basis of a detection signal obtainable out of a combustion state detecting sensor OS, in order to make the specified quantity of fuel into a complete combustion by means of the suction air heater in time of engine starting, a control unit 50, which controls at least either of the control valve 19 and the throttle valve 8, is installed there. Thus, a starting characteristic is sharply improvable and what is more, smoke emission in an exhaust passage is checkable.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention improves the J performance by increasing the intake air temperature using a combustion type intake air heating heater when starting a diesel engine. The present invention relates to a process 8 for promoting starting of a diesel engine.

(Prior art) In order to improve the startability of diesel engines so that they can be started reliably and smoothly in cold and cold weather, as a starting accelerator device that is attached to the engine body,
There are those that use an electric intake air heating heater placed in the intake passage, and those that burn fuel in the intake i1 circuit using an electrical heating section as shown in Japanese Patent Application Laid-Open No. 50-44351. There are known devices that use a combustion type intake air heating heater that heats the air. Among these, startup accelerators that use combustion-type intake air heating heaters are superior to those that use electric intake air heating heaters in terms of heating, thermal efficiency, and energy cost for heating intake air. It has the advantage of being

However, in a startup promotion device using a combustion-type intake air heating heater, the amount of fuel burned by the intake air heating heater tends to fluctuate depending on its viscosity, etc. Oxygen in the intake air is consumed during the combustion of fuel, but the amount of intake air flowing through the intake passage not only changes depending on the engine speed, but also changes due to changes in the outside temperature and atmospheric pressure.
It has conventionally been difficult to constantly burn an appropriate amount of fuel in the intake passage for the amount of intake air. and,
If the amount of fuel combusted in the intake passage is larger than the appropriate amount for the amount of intake air, the amount of oxygen in the intake air that is consumed for the combustion of fuel in the intake air heating heater will increase. As the ratio increases, there will be a shortage of oxygen for combustion in the combustion chamber of the engine body,
Not only is it not possible to improve the initial mh property, but there is also the inconvenience that smoke is discharged into the exhaust passage. Conversely, if the amount of fuel combusted in the intake passage is too small than the appropriate amount, the intake air heating heater will not generate enough heat to raise the intake air to the desired temperature, resulting in The problem is that it will not be possible to significantly improve sexuality.

(Object of the Invention) In view of the above, the present invention heats intake air by a combustion-type intake air heating heater arranged in the intake passage when starting a diesel engine, and Even if there are fluctuations in the viscosity of the fuel burned by the intake air heating heater or fluctuations in the amount of intake air, the intake air heating heater can maintain the desired amount of intake air without causing a lack of oxygen for combustion in the combustion chamber of the engine body. It is possible to fully combust enough fuel to generate enough heat to raise the temperature to The purpose of the present invention is to provide a starting promotion device for a diesel engine.

(Structure of the Invention) A diesel engine starting promotion device according to the present invention is provided with a bypass which is formed in an intake J path of a diesel engine to be separated from a main passage, and which allows a part of intake air to pass through and is supplied to the engine body. a passage section, a combustion-type intake air heating heater disposed in the bypass passage section that burns fuel to generate heat, and a combustion type heater that changes the amount of fuel combusted by the intake power An adjustment means, a valve means for changing the amount of intake air flowing through the bypass passage, a combustion state inspection sensor for detecting the combustion state of the fuel burned by the intake air heating heater in the bypass passage, and a combustion state detection sensor. Based on the obtained pressure detection signal, when starting the diesel engine, UII controls one of the fuel adjustment means and the valve means so that the intake air heating heater completely burns a predetermined amount of fuel.
(iii) 1.1.

With this configuration, if the appearance of #A:r-) combusted by the intake force 11 heat heater varies depending on its Ri degree, or when the intake air flowing through the intake passage changes depending on the engine rotation. Even if the number of fuels varies depending on the number or changes in outside temperature or atmospheric pressure, the start control means allows the intake air heating heater to fully burn the desired fuel in the bypass passage, and the engine Control is performed so that intake air containing a sufficient amount of oxygen for combustion in the combustion chamber of the main body is supplied from the intake passage to the combustion chamber, so that there is no shortage of oxygen for combustion in the combustion chamber. (The temperature of the intake air supplied to the combustion chamber can be sufficiently raised.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the color-preserving diesel engine start acceleration device according to the present invention together with the main parts of a diesel engine to which it is applied. In FIG. It is provided to supply intake air to the combustion chamber 4 of the engine body 3,
The intake air sent into the combustion chamber 4 from the intake passage 1 causes fuel injected into the combustion chamber 4 from a fuel injection nozzle (not shown) to burn, and exhaust gas generated by this combustion is discharged to the exhaust passage 5. The intake passage 1 includes a main passage portion 6.
A bypass passage part 7 is formed which is separated from the main passage part 6. A part of the intake air introduced into the intake passage 1 is guided to the bypass passage part 7 and flows through the main passage part 6. It flows through the bypass passage section 7 in a state separated from the air, and then merges with the intake air that has flowed through the main passage section 6 and is supplied to the combustion chamber 4.

A first throttle valve 8 is installed near the inlet of the bypass passage 7, and a second throttle valve 9 is installed near the inlet of the main passage 6. The first throttle valve 8 and the second throttle valve 9 are rotated by negative pressure responsive diaphragm mechanisms 11 and 12, respectively, and the negative pressure four-person compartment 11a and Negative pressure from, for example, a vacuum pump 14 driven by a crankshaft (not shown) of the engine body 3 is supplied to the vacuum pump 12a through dedicated pipes 15 and 16. A first duty control valve 17 and a second duty valve 18 are respectively installed in these dedicated pipes 15 and 16. When the valve 18 is turned on, negative pressure from the vacuum pump 14 is introduced into the negative pressure introduction chambers 11a and 12a of the diaphragm mechanisms 11 and 12 via the dedicated pipes 15 and 16, respectively.

When the first duty control valve 17 and the second duty control valve 18 are turned off and negative pressure is not introduced into the negative pressure introducing chambers 11a and 12a of the diaphragm mechanisms 11 and 12, the first throttle valve 8th and 2nd
The throttle valve 9 is kept fully open.

Further, a portion of the bypass passage section 7 downstream of the first throttle valve 8 has a 1lTl electric glow section 23'', and the electric glow section 23'' is supplied with fuel supplied from the feed pump 20 via the conduit 21. A combustion-type intake air heating heater 23 is installed, and the amount of fuel burnt by this intake air heating heater 23 is controlled by a third duty control wholesaler 19 interposed in the core pipe 21. It is adjusted 3 times by i
'J is made to do so.

Further, an oxygen sensor O3 is provided downstream of the intake air heating heater 23 in the bypass passage section 7, and this oxygen sensor O3 is combusted by the intake air heating heater 23 in the bypass passage section 7. In order to detect the combustion state of the fuel, the amount of oxygen (oxygen). The signal is output to the control unit 50.

This excess air ratio λ becomes 1 when the fuel is completely combusted in an overpressure state in the intake force U heating heater 23, which means that there is excess oxygen! It is greater than 1 when combustion is occurring at a distance of 1 meter, and is smaller than 1 when combustion is occurring at 1 meter due to lack of oxygen.

The control unit 50 includes the above-mentioned detection signal ISO.
In addition, a detection signal ISn indicating the engine rotational speed Ne obtained from the rotational speed sensor NS and a detection signal ISs indicating the engine cooling water TS obtained from the water temperature sensor SS are inputted. There is. Then, when starting the engine, the control unit 50
For these detection signals ISo, ISn, and ISs, control signals CP, CP2, and CPs, each shaped into a pulse having a predetermined duty, are generated to obtain the first density system. Wholesale barf 17. It is supplied to the second duty control valve 18 and the third duty control valve 19, respectively, and is also supplied to the intake air heating heater 23.
Control by supplying heating current OD to l thermoelectric 23゛? ffl
1, and is it the first VJ system? il1 means.

Based on the above-mentioned configuration, the control unit 50 which forms the starting control means when the engine is running most of the time.
According to the first duty system;
The control unit 50 controls the duty control knob 18 and the third duty control valve 19, and also supplies the heating current OD to the intake air heating heater 23. For example, a microcomputer is used to control the operation of the control unit 50 and the operation of each part controlled by the control unit 50, using a central controller of the microcomputer used in the control unit 50. An example of a program executed by the processing unit (CPU) will be described below with reference to the flowchart shown in FIG.

When the starting switch (not shown) is turned on to start the diesel engine shown in FIG.
The program shown in the flowchart of FIG. 2 in the control unit 50 is started, and first, in process 31, a detection signal ISs is taken in which detects the engine cooling water temperature Ts obtained from the water temperature sensor SS, and in subsequent decision 32, the detection signal ISs is taken in. 15s, the engine cooling water temperature Ts is below a predetermined temperature, for example, 5°C.
Determine whether the following is true. Here, if the engine cooling water temperature Ts is 5°C or less, it is necessary to heat the intake air introduced into the combustion chamber 4 during cold and cold weather, so proceed to process 33 and heat the Current OD
is supplied to the energized red-hot part 23' of the intake air heating heater 23. In this way, the heating current OD is applied from the control unit 50 to the energized red-hot part 23'' of the intake air heating heater 23.
As a result, the energized red-hot part 23' of the intake air heating heater 23 becomes red-hot and becomes a heat-generating state.

Next, in process 34, control signals CP and CF2
are supplied to the first duty control valve 17 and the second duty control valve 18, respectively.

Here, from the control unit 50, the control signal CP
+ and CF2 are supplied to the first duty control valve 17 and the second duty control valve 1, so that the first throttle valve 8 and the second throttle valve 9 have opening degrees Ka and Kb for starting, respectively. The valve shall be opened at a predetermined degree so that the

Then, when the starter switch is turned on and cranking of the engine body 3 is performed, a detection signal ISn indicating the engine rotation speed NC obtained from the rotation speed sensor NS is captured in a process 35.
In the subsequent decision 36, it is determined whether or not cranking of the plow engine main body 3 has started based on the detection signal ISn. Here, if it is determined that cranking has not started, the process returns to process 35 and the determination at decision 36 is repeated. If it is determined in decision 36 that cranking has started, process 37
Then, the control wholesale signal CP, which has a constant duty, is sent to the third
The third duty control valve I9 is electrically excited. This results in
The third duty control valve 19 is set to the ON state JG with a certain opening degree, and a certain amount of fuel is supplied from the feed pump 20 to the intake air heating heater 23. The fuel supplied to this intake air heating heater 23 is combusted in the energized glowing section 23'' of the intake air heater 23.

That is, it is combusted within the bypass passage section 7.

In such a state, the intake air flows through the bypass passage section 7 and the main passage section 6 at a predetermined ratio according to the starting opening degrees Ka and Kb of the first throttle valve 8 and the second throttle valve 9, respectively. At this time, the amount of intake air flowing through the bypass passage section 7 is set to be the minimum amount necessary to achieve complete combustion of the fuel in the intake air heating heater 23.

Therefore, if the viscosity of the fuel 4 supplied to the intake air heating heater 23 from the feed pump 20 via the third duty control valve 19 does not fluctuate, four people are placed in the bypass passage section 7. The intake air maintains the complete combustion state 6 of the fuel in the intake force 11 and heat heat 23, and the detection signal ISo obtained from the oxygen sensor O3 indicates an excess air ratio λ of 1.

Next, the din 38 determines whether the air-fuel mixture in the combustion chamber 4 is in a complete explosion state. This judgment can be made, for example, in times I! The detection signal 1sr+↓ is made by detecting the engine speed 13Ne obtained from the i, - number sensor NS, and if the engine speed Ne has reached a predetermined rotational failure, it is determined that the engine is in a complete explosion state. to decide. Here, if it is determined that the air-fuel mixture is not in a complete explosion state in the combustion chamber 4, the process proceeds to process 39, where the excess air ratio λ obtained from the oxygen sensor O8 is taken in as the hail detection signal 1so, and the next In decision 40, it is determined whether or not the excess air ratio λ is 1 for the detection signal ISo. If the excess air ratio λ is 1, the fuel is completely combusted in the intake air heating heater 23, so the process returns to decision 38 and it is determined whether or not the air-fuel mixture is in a complete explosion state in the combustion chamber 4. is repeated, and if it is determined that the excess air ratio λ is not 1, the process proceeds to decision 41, where it is determined whether the excess air ratio λ is greater than 1. As a result of the judgment in this dinsion 41, if the excess air ratio λ is larger than 1, that is, for example, a change in the viscosity of the fuel from the feed pump 20 occurs, and the third When the amount of fuel supplied through the duty control valve 19 decreases and the fuel is burned in an oxygen-rich state in the intake air heating heater 23, the amount of fuel supplied to the intake air heating heater 23 decreases. Since there is a shortage, in process 42, the third duty control valve 19 is The duty of the IIl signal cp3 is changed to increase the opening degree of the third duty control valve 19, and the intake air heating heater 2
A1. Correct to increase the amount of fuel available. As a result, the amount of fuel combusted in the energized red-hot section 23' of the intake air heating II upper heater 3 in the bypass passage section 7 is increased, and the complete combustion state where the excess air ratio λ is 1 is returned. This avoids insufficient heating of the intake air placed in the combustion chamber 4 by four people. Then decision 38 again
Return to

On the other hand, if the excess air ratio λ is smaller than 1 in decision 41, that is, for example, the amount of intake air flowing through the bypass passage section 7 decreases, and the fuel in the intake air heating heater 23 is deficient in oxygen. If it is burning in
The fuel is incompletely combusted in the intake air heating heater 23, and the fuel supplied to the intake air heating heater 23 that is not combusted in the bypass passage section 7 is burned from the bypass passage section 7. The fuel from the bypass passage section 7 is injected into the combustion chamber 4 from the fuel injection nozzle and applied to the regular fuel supplied to the combustion chamber 4. The T insufficient condition stops and the exhaust passage 5 is widened to allow smoke to be discharged. Therefore, in such a case, process 43
control to supply the first duty control valve 17?
all (, R issue, CP + The duty of CP + is changed to increase the opening degree of the first duty control valve 17. The opening degree of the throttling hub 8 is corrected to an opening degree Ka' larger than the starting opening degree Ka.

Therefore, the volume of intake air flowing through the bypass IF+B section 7 is increased, and as a result, the intake air heating heater 23
The amount of oxygen in the energized red-hot section 23' is increased. As a result, the fuel supplied to the intake air heating heater 23 is completely twisted in the bypass IF+ passage section 7.
The supply of undesired excess fertilizer to the combustion chamber 4 is avoided. After that, the process returns to decision 38 again.

On the other hand, if it is determined in decision 38 that the air-fuel mixture is in a complete explosion state in the combustion chamber 4, cranking of the engine body 3 has been completed and the engine body 3 is in a complete explosion state in which it can rotate on its own. Proceed to 1st duty system fIll /＼lube 17° 2nd duty system?
[j valve 18. Control fill signal c for each of the third duty control valve 19 and the intake air heating heater 23
p,, CPz and CP.

And the supply of heating current OD is stopped. In this way, H! from the control unit 50! 'I? The first duty control valve 17 and the second duty control valve 18, to which the supply of the In signals CP and CP z is stopped, are closed, respectively, and as a result, the first throttle valve 8 and the second The throttle valve 9 is fully opened. Also,
;1□'I il! A third duty system where the supply of I signal CP Yu is stopped? The Iil valve 19 is also closed, the supply of fuel from the feed pump 20 to the intake air heating heater 23 is stopped, and the supply of the current OD for heating the intake air is stopped. At night 23, the system is brought into an inactive state, and heating of the intake air in the bypass passage section 7 is stopped. This completes the control that occurs when starting the diesel engine.

Also, as a result of Decision 32, the cooling water 'in'
If T S is greater than 5° C., there is no need to heat the intake air introduced into the combustion chamber 4, and the process goes directly to process 44, where each control signal CPI is adjusted as described above.
, CF2 and the supply of CF2 and heating current ○D are stopped.

After the control at the time of starting is completed as described above, the diesel engine opens the first throttle valve 8 and the second throttle valve 8.
It is operated with the throttle valve 9 in the fully open state.

In the above example, the amount of intake air flowing through the bypass passage section 7 is controlled using the first throttle valve 8 and the second throttle valve 9, and the amount of intake air flowing through the bypass passage section 7 is controlled using the first throttle valve 8 and the second throttle valve 9. When the excess air ratio λ in the bypass passage section 7, which is generated by the signal ISo, is larger than 1, the control signal CP s supplied to the third duty control controller 11 valve 19 is increased by 73 degrees to control the intake air. The amount of fuel supplied to the heating heater 23 is corrected to increase, and furthermore, when the excess air ratio λ flowing into the bypass passage section 7 is smaller than 1, the opening degree of the first duty control valve 17 is increased. Although the opening degree of the first throttle valve 8 is corrected to increase, the diesel engine starting promotion device according to the present invention does not necessarily have to have such a +11 configuration. Only the opening degree of the first throttle valve 8 provided in the bypass passage section 7 is based on a signal obtained from a combustion state detection sensor such as an oxygen sensor O3, which is arranged downstream of the intake air heating heater 23 in the bypass passage section 7. Feedback control may also be carried out when the diesel engine is started. The temperature of the intake air introduced into the engine can be effectively increased, and the startability of the diesel engine can be improved.

Further, in the above description, the control mode has been explained in the case where there is a fluctuation in the viscosity of the fuel supplied to the intake air heating heater, but according to the diesel engine start promotion device according to the present invention, the intake passage Even if the amount of intake air flowing through the intake air fluctuates due to changes in outside temperature or atmospheric pressure, a detection signal obtained from a combustion state detection sensor such as an oxygen sensor placed downstream of the intake air heating heater in the bypass passage. By controlling the amount of fuel supplied to the intake air heating heater and/or the amount of intake air flowing through the bypass passage section based on the above, the same effects as described above can be obtained.

(Effects of the Invention) As is clear from the above description, according to the diesel engine starting promotion device according to the present invention, the intake passage is provided with a bypass passage section in which a combustion-type intake air heating heater is installed. 'jM f' below the intake air heating heater that goes down to the bypass passage! Based on the detection signal obtained from the combustion type one-voice detection means installed in the BJ, the intake force 11p,
If the amount of fuel supplied to the intake air heating heater fluctuates due to feed puncture control of the amount of fuel supplied to the heater and/or the intake air flowing through the bypass passage, or if the amount of fuel supplied to the intake air heating heater changes, or Even if the amount of fuel fluctuates not only due to engine speed but also changes in outside temperature and atmospheric pressure, the fuel combusted by the intake air heater in the bypass passage is completely combusted, and the engine body Since intake air containing sufficient oxygen for combustion in the combustion chamber is supplied from the intake passage to the combustion chamber, oxygen can be supplied to the combustion chamber without causing a shortage of oxygen for combustion in the combustion chamber. The temperature of the intake air can be sufficiently increased by 1. Therefore, it is possible to significantly improve the startability of a diesel engine to which the diesel engine start promotion device according to the present invention is applied, and to prevent smoke from being discharged into the exhaust IIT circuit when starting the diesel engine. ); You will be able to do it for a while.

4. Simple explanation of I21 Figure 1 is an IQ schematic configuration diagram showing an example of the diesel engine almost motion accelerating device according to the present invention together with a diesel engine to which it is applied, and Figure 2V is shown in Figure 1. 3 is a flowchart illustrating an example of an operation program of a microcomputer in an example of a control unit used in the example.

In the figure, 1 is an intake passage, 4 is a combustion chamber, 6 is a main passage part, 7 is a bypass passage part, 8 is a first throttle valve, 9 is a second throttle valve, and 17 is a first duty control I. \Lube, 1
8 is a second duty control valve, 19 is a third duty control valve, 20 is a feed pump, 23 is a heater for heating intake air, 50 is a control unit, and O8 is an oxygen sensor.

Figure 2

Claims (1)

[Claims] The intake passage of a diesel engine is separated from the main passage and has a bypass passage through which part of the intake air supplied to the engine body passes, and a combustion type in which fuel is burned within the bypass passage to generate heat. a heater for heating intake air, a fuel adjustment means for changing the amount of fuel burned by the heater for heating intake air, a valve means for changing the amount of intake air flowing through the bypass passage, and a heater for heating the intake air in the bypass passage. Based on a combustion state detection sensor that detects the combustion state of fuel combusted by the heating heater, and a detection signal obtained from the combustion state detection sensor, when the diesel engine is started, the intake air heating heater A starting promotion device for a diesel engine, comprising a starting control means for controlling at least one of the fuel adjusting means and the valve means so that a fixed amount of fuel is completely combusted.