JPS6212375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for an automobile diesel engine.

Unlike gasoline engines, diesel engines generally do not have a throttle valve in the intake passage, so the amount of intake air becomes excessive during light loads, especially when idling, which increases engine compression resistance and causes torque fluctuations. This is likely to occur. Therefore, there is a problem in that the engine vibrates due to this torque fluctuation and vibration noise is generated.

As a means to solve this problem, an intake shutter (equivalent to a throttle valve in a gasoline engine) is installed in the intake passage so that it can be opened and closed, and when the accelerator pedal is released, the intake shutter is closed and the intake passage is throttled. It is known to use an intake shutter device that reduces the amount of intake air to reduce the amount of engine vibration and vibration noise (for example, see Japanese Patent Laid-Open No. 52-8217).

Additionally, with a diesel engine, extra load is placed on the engine when operating the compressor to use the car cooler, operating the hydraulic pump to tilt the loading platform of a dump truck, or operating the mixer of a mixer truck. Since the engine speed decreases, during idling operation, the amount of fuel injected from the fuel injection pump is increased by the action of the governor, working to prevent the engine speed from decreasing and output corresponding to the load.

Therefore, in a diesel engine equipped with the above-mentioned intake shutter device, while the amount of fuel supplied increases when the auxiliary equipment is driven in the idling operating state as described above, the amount of intake air is limited by the intake shutter device. As a result, the overall condition is a lack of oxygen, which causes problems such as partial misfires and the emission of white smoke and odor (formaldehyde).

The present invention has been made in view of the above problems, and provides an intake system for an automotive diesel engine that supplies air necessary for good combustion of increased fuel when driving auxiliary equipment that places an extra load on the engine. The purpose is to provide.

In order to achieve the above object, the present invention has an intake shutter provided in an intake passage, and a system that is linked to the intake shutter device and closes the intake shutter when the load is light in response to a signal related to the amount of depression of the accelerator pedal. It has an intake shutter device that throttles the engine speed and reduces vibration, and a mechanical governor mechanism that adjusts the amount of fuel to increase as the rotation speed decreases for the same amount of accelerator pedal depression, depending on the amount of accelerator pedal depression and engine rotation speed. A diesel engine equipped with a fuel injection pump and an auxiliary device driven by the engine, further comprising a device linked to the intake shutter device to reduce the throttle amount of the intake shutter device when the auxiliary device is driven, and further comprising: The intake throttle amount of the shutter device is set so that the intake negative pressure downstream of the intake shutter is 100 to 400 mmHg when the engine is idling and when the engine is warmed up and the auxiliary equipment is not being driven. It is something to do.

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

Embodiment 1 In FIG. 1, 1 is an engine, and 2 and 3 are an intake passage and an exhaust passage that communicate with the combustion chamber of the engine 1, respectively. An intake shutter 4 composed of a butterfly valve is attached to the intake passage 2, and an exhaust brake valve 5 is attached to the exhaust passage 3 so as to be openable and closable.

The intake shutter 4 and the exhaust brake valve 5 are connected to first and second power chambers 8 and 9 via link mechanisms 6 and 7, respectively, and the negative pressure chambers 8a of the first and second power chambers 8 and 9 are connected to each other via link mechanisms 6 and 7, respectively. , 9a are held at the open position (see solid lines in Figure 1) when they are at atmospheric pressure, while when the negative pressure chambers 8a, 9a of the first and second power chambers 8, 9 are at negative pressure, Diaphragms 8b and 9b are springs 8c,
It is configured to be displaced against the elastic force of 9c and to be in the closed position (see the dashed line in FIG. 1).

Negative pressure chambers 8a and 9a of each power chamber 8 and 9
are the first and second three-way solenoid valves 1, respectively.
It is connected to a vacuum tank 13 through a negative pressure passage 12 in which pipes 0 and 11 are interposed. A vacuum pump 14 driven by the engine 1 is connected to the vacuum tank 13 via a check valve 15. Both three-way solenoid valves 10, 1
1 closes the negative pressure passage 12 and connects the negative pressure chambers 8a, 9a of the power chambers 8, 9 to the air holes 10b,
It is opened to the atmosphere via 11b, and when activated, the negative pressure passage 12 is opened to communicate the negative pressure chambers 8a and 9a with the vacuum tank 13.

16 is a first bypass passage that connects the upstream and downstream sides of the intake shutter, and is equipped with a solenoid valve 17 that opens only when the exhaust brake is activated and a muffler 18 (enlarged chamber) that dampens intake noise when the exhaust brake is activated. There is.

Reference numeral 19 denotes an on-off valve that opens when an auxiliary device is driven, which will be described later. A second bypass passage 20 is formed through the on-off valve 19 to connect the upstream side and the downstream side of the intake shutter 4.

21 is a battery with one end grounded, and a key switch 22 that closes when operating the engine 1 and a key switch 22 that is closed when the engine 1 is operated, and a key switch 22 that is connected to the battery 21 only when the engine 1 is started, more precisely during cranking and for a few seconds after cranking. a starting relay switch 23 that is opened;
An accelerator switch 24 that opens when the accelerator pedal is depressed and closes when the accelerator pedal is released is connected in series with each of the accelerator switches 24. Furthermore, in relation to the accelerator switch 24, there is an exhaust brake switch 25 that is manually opened and closed at the driver's selection, a clutch switch 26 that opens when a clutch pedal (not shown) is depressed and closes when it is released, and a shift lever that is in the neutral position. A neutral switch 27 that opens when the gear is in the gear position and closes when the gear is in the shift position are connected in series. Further, one terminal of the first three-way solenoid valve 10 is connected between the accelerator switch 24 and the exhaust brake switch 25, and the other terminal is grounded. Furthermore, one terminal of the second three-way solenoid valve 11 is connected to the neutral switch 27, and the other terminal is grounded.

A starter switch 28 is connected to the base of a transistor 30 via a resistor 29.
The collector of the transistor 30 is connected to an exciting coil 23a (starting relay switch 23) in parallel with the starter switch 28, and the emitter is grounded. A capacitor 31 and a further resistor 32 are connected in series between starter switch 28 and resistor 29, which resistor 32 is grounded. These close the starting relay switch 23 during cranking when the starter motor is operating and for several seconds thereafter, so as not to impede the startability of the engine.

Note that when the key switch 22 is closed, a fuel passage of a fuel injection pump 40, which will be described later, is opened, but when the key switch 22 is opened, the fuel passage is closed and the engine is stopped.

33 is a cooler switch, one terminal of which is connected between the key switch 22 and the starting relay switch 23, and the other terminal of which the excitation coil 34a of the relay switch 34 and the diode 35 are connected in parallel. Furthermore, the diode 35 is connected to the on-off valve 1.
It is connected to No. 9 excitation coil 19a. The relay switch 34 is electrically connected to an electromagnetic clutch 38 that connects and disconnects a pulley 36 that rotates on the output shaft of the engine 1 and a compressor 37 that operates a car cooler.

Reference numeral 39 denotes an auxiliary drive detection switch, which is provided in parallel with the cooler switch 33 and the diode 35. This auxiliary equipment drive detection switch 39 is closed when the so-called auxiliary equipment is activated, such as operating a hydraulic pump to tilt the loading platform of a dump truck, or extracting output from the engine 1 to drive a mixer truck. . Normally, such auxiliary equipment is driven by a manual lever provided at the driver's seat, and therefore, an auxiliary equipment drive detection switch 39 is provided in conjunction with the manual lever.

40 is a distribution type fuel injection pump, the control lever 40a of which is interlocked with an accelerator pedal, and the amount of fuel injected is determined by the amount of depression of the accelerator pedal and the engine rotation speed. Accordingly, the engine has a known governor mechanism that corrects the amount of fuel in an increasing direction as the rotational speed decreases for the same accelerator pedal depression amount in accordance with the accelerator pedal depression amount and the engine rotational speed.

41 is an air cleaner.

According to the above configuration, during idling operation when the engine 1 is warmed up, since the accelerator pedal is released, the accelerator switch 24
closes. At this time, the solenoid valve 17 and the on-off valve 1
9 are both closed, the first and second bypass passages 16, 20 remain closed.

By closing the accelerator switch 24, the first
Since the three-way solenoid valve 10 is energized and opened, negative pressure is introduced from the vacuum tank 13 into the negative pressure chamber 8a of the first power chamber 8 through the negative pressure passage 12, and the diaphragm 8b sucks air through the link mechanism 6. The shutter 4 rotates to the closed position (see the one-dot chain line in Figure 1).

The amount of restriction of the intake shutter device in this closed position is 100 mmHg or more and 400 mmHg or less (preferably 150 mmHg or less).
mmHg to 350mmHg) to suppress engine vibration and noise during idling.
Here, the throttle amount of the intake shutter device is expressed as the intake negative pressure downstream of the intake shutter during idling, that is, when the engine is rotating at 600 rpm, and experiments have shown that the above range is desirable. , has been confirmed.

Furthermore, when the car cooler is operating, which places a load on the engine 1, when the loading platform of a dump truck is tilted, or when the mixer of a mixer truck is operating, the cooler switch 33 or the auxiliary drive detection switch 39 is closed, and the excitation coil 19a of the on-off valve 19 is closed. Since the second bypass passage 20 is excited and the second bypass passage 20 is opened, the substantial passage cross-sectional area of the intake passage 2 increases, and the amount of throttling of the intake shutter device is reduced.

As a result, the amount of intake air commensurate with the increased amount of injected fuel due to the load applied to the engine 1 during idling is taken in, resulting in a good combustion state without causing half-misfire.

Also, during exhaust braking, when the exhaust brake switch 25, clutch switch 26, and neutral switch 27 are closed and the exhaust brake valve 5 is in the closed position (see the one-dot chain line in Figure 1), the first bypass passage 16 opens and the intake air is The amount of throttling of the shutter device is reduced. This is to prevent the gas compressed in the engine from flowing back into the intake passage 2 and rapidly expanding during exhaust braking, causing intake noise. This is because when the device is throttled down, the amount of intake air supplied into the combustion chamber is small, so that sufficient compression loss cannot be caused in the engine, and the braking performance of the exhaust brake is significantly degraded.

Since the clutch switch 26 and the neutral switch 27 in the above embodiment are used to distinguish between idling and deceleration operation,
Instead of these switches 26, 27, it is also possible to use a rotational speed switch that opens when the engine is idling and closes when the engine rotational speed is slightly higher than that at idling.

The accelerator switch 24, clutch switch 26, and neutral switch 27 do not necessarily have to be of a type that directly responds to the movement of the accelerator pedal, clutch pedal, and shift lever, but may be of a type that indirectly informs the movement. good. For example, the accelerator switch 24 may be a switch that detects the position of the control lever 40a of the fuel injection pump 40.

Note that the exhaust brake switch 25 of the above embodiment
is not necessarily required and may be omitted.

In the first embodiment described above, in order to reduce the amount of throttling of the intake passage 2 when driving the auxiliary equipment, this is done by slightly increasing the opening degree of the intake shutter 4.
Reducing the amount of restriction in the intake passage 2 means that
Substantive intake passage area (opening area) of intake passage 2
Since the purpose is to increase , in addition to Example 1,
Of course, the opening degree of the intake shutter 4 itself can be slightly increased when the auxiliary equipment is being driven, but it is also possible to disable the intake shutter device when the auxiliary equipment is being driven, as shown in the second embodiment below.

Embodiment 2 In FIG. 2, 51 is a relay switch, which connects the accelerator switch 24 and the first three-way solenoid valve 10.
It is interposed between. The relay switch 51
is electrically interlocked with the cooler switch 33 or the auxiliary equipment detection switch 39, and these switches 3
3 and 39 are closed, and the first three-way solenoid valve 10 is rendered inoperable.

With this configuration, when the relay switch 51 is open and the auxiliary equipment is being driven, even if the accelerator pedal is released and the accelerator switch 24 is closed, the first three-way solenoid valve 10 will not open and the negative pressure will remain at the first power. Since the air is not introduced into the negative pressure chamber 8a of the chamber 8, the intake shutter 4 will not be closed to the closed position.

As a result, the intake shutter 4 is kept fully open when the auxiliary equipment is being driven, and sufficient intake air is sucked in to achieve a good combustion condition.

Note that this example has substantially the same configuration as Example 1, so the same reference numerals are used for similar components, and only the main parts will be described.

In Embodiments 1 and 2, the intake shutter 4 is closed only when the accelerator pedal is released (during idling), and is fully opened at other times; Even during low-speed rotation, which is slightly higher than the rotational speed (600r.pm), there is still a lot of excess air and torque fluctuations, so it is desirable to reduce the intake air with an intake shutter device.

However, even at low speed rotation, the required air amount increases and is large at high load with a large amount of fuel injection, so it is not preferable to reduce the intake air by the intake shutter device. This is because the advantage of a diesel engine is its high thermal efficiency, and it is not desirable to throttle the intake air in the normal operating range.

Therefore, it can be seen that the intake shutter device should be throttled during low rotations and light loads, and fully opened during medium rotations and medium loads.

Next, a description will be given of an intake shutter device that solves the above problems by continuously changing the opening degree of the intake shutter.

Embodiment 3 In FIG. 3, 61 is an intake shutter, which is interlocked with an accelerator pedal 62 via a link mechanism 63. The opening degree of the intake shutter 61 is the fourth
As is clear from the figure, it is fully closed during idling, and the amount of depression of the accelerator pedal 62 becomes large, increasing the engine speed (when using a fuel injection pump using an all-speed governor) or the load (when using a limit-speed governor). It is set so that it gradually increases as the value (case) increases, and becomes fully open when it reaches a predetermined value.

Note that the overall configuration of the above embodiment is substantially the same as that of the first embodiment, so the same reference numerals are used for similar components, and detailed explanation thereof will be omitted.

Since the present invention is configured as described above, the amount of throttle of the intake shutter device is reduced when the auxiliary equipment is driven, and sufficient intake air is supplied when the auxiliary equipment is driven.
This has an excellent practical effect in that a good combustion state can be obtained without any difference from normal idling.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention; FIG. 1 is an overall configuration diagram of the intake system of a diesel engine according to Embodiment 1, FIG. 2 is a configuration diagram of the same essential parts of Embodiment 2, and FIG. FIG. 4 is a diagram showing the configuration of the same essential parts of Example 3, and FIG. 4 is a diagram showing the characteristics of the accelerator pedal of Example 3. DESCRIPTION OF SYMBOLS 1... Engine, 2... Intake passage, 3... Exhaust passage, 4... Intake shutter, 5... Exhaust brake valve, 6, 7... Link mechanism, 8... First power chamber, 9... 2nd power chamber, 8a,
9a...Negative pressure chamber, 8b, 9b...Diaphragm,
8c, 9c... Spring, 10... First three-way solenoid valve, 11... Second three-way solenoid valve, 1
0a, 11a... Excitation coil, 10b, 11b...
...Atmospheric hole, 12... Negative pressure passage, 13... Vacuum tank, 14... Vacuum pump, 15...
Check valve, 16... First bypass passage, 17...
... Solenoid valve, 18 ... Silencer, 19 ... Opening/closing valve, 1
9a...Excitation coil, 20...Second bypass passage, 21...Battery, 22...Key switch,
23... Start relay switch, 23a... Excitation coil, 24... Accelerator switch, 25... Exhaust brake switch, 26... Clutch switch,
27... Neutral switch, 28... Starter switch, 29, 32... Resistor, 30... Transistor, 31... Capacitor, 33... Cooler switch, 34... Relay switch, 34a...
... Excitation coil, 35 ... Diode, 36 ... Pulley, 37 ... Compressor, 38 ... Electromagnetic clutch, 39 ... Auxiliary drive detection switch, 40 ...
...Fuel injection pump, 40a...Control lever, 41...Air cleaner, 51...Relay switch, 61...Intake shutter, 62...Accelerator pedal, 63...Link mechanism.

Claims (1)

[Claims] 1. An intake shutter provided in the intake passage, which is connected to a signal related to the amount of accelerator pedal depression, and closes the intake shutter when the load is light to reduce the amount of intake air and reduce vibration. a fuel injection pump having a mechanical governor mechanism that corrects the amount of fuel in an increasing direction as the rotation speed decreases for the same accelerator pedal depression amount according to the accelerator pedal depression amount and the engine rotation speed; A diesel engine equipped with an auxiliary device driven by a diesel engine, further comprising a device linked to the intake shutter device to reduce the amount of throttle of the intake shutter device when the auxiliary device is driven, and further reduce the amount of intake throttle of the intake shutter device. An intake air intake of an automobile diesel engine, characterized in that the intake pressure downstream of the intake shutter is set to be 100 to 400 mmHg when the engine is idling and when the engine is warmed up and the auxiliary equipment is not driven. Device. 2. A device for reducing the throttle amount of an intake shutter device has a bypass passage that communicates the intake passage between the upstream side and the downstream side of the intake shutter, and an opening/closing means that is interposed in the bypass passage and opens when auxiliary equipment is driven. An intake system for an automotive diesel engine according to item 1. 3. The intake system for an automobile diesel engine according to claim 2, wherein the opening/closing means is a solenoid valve and is electrically linked to a detection means for detecting whether or not the auxiliary equipment is in operation. 4. The automotive diesel engine according to claim 1, wherein the device for reducing the throttle amount of the intake shutter device is a relay switch that is linked to the intake shutter device and disables the operation of the intake shutter device when driving auxiliary equipment. intake device. 5. The intake shutter device is configured such that the intake shutter is interlocked with an accelerator pedal, and the opening degree of the intake shutter changes continuously according to the amount of depression of the accelerator pedal. The intake system for the automobile diesel engine described above.