JPS6244100Y2 - - 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.

However, in the above device, the intake passage is constricted to the same extent as when idling when the engine brake is applied during deceleration, so there is noise caused by air column vibration in the intake passage due to intake pulsation, and gas compressed in the engine during exhaust braking. Although it is possible to reduce the intake noise caused by the rapid expansion of intake air flowing back into the intake passage, the amount of intake air supplied into the combustion chamber is reduced too much, making it impossible to cause sufficient compression loss in the engine. There is a problem that the braking performance of the engine brake decreases.

Therefore, during deceleration when the engine brake is activated (including when the exhaust brake is activated), it is necessary to reduce the throttle amount of the intake shutter device compared to when the engine is idling when the accelerator pedal is released.

Therefore, the applicant focused on the fact that the state in which the engine brake is activated and the state in which the engine brake is not activated can be distinguished depending on whether the transmission is in a shifted state or in a neutral state. This led to the development of an intake system for automobile diesel engines that is equipped with a device that can change the amount of throttle.

This invention reduces intake noise during engine braking in a diesel engine intake system equipped with an intake shutter device that closes the intake shutter installed in the intake passage and throttles the amount of intake air when the accelerator pedal is released. To provide an intake device for a diesel engine for an automobile, which has a high engine braking performance and is not inferior in terms of engine braking performance.

In order to achieve the above objective, the throttle amount of the intake shutter device is set to 100 mm so that the intake negative pressure downstream of the intake shutter is 100mm when the engine is idling after the engine has warmed up.
The present invention is characterized in that it is set to be equal to or higher than Hg, and is further provided with a device that reduces the set throttle amount of the intake shutter device when the transmission is in a shift state.

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

<Example 1> In FIG. 1, 1 is an engine, and 2 and 3 are an intake passage and an exhaust passage, respectively, which communicate with the combustion chamber of the engine 1. 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).

The first power chamber 8 switches between two stages, an open position and a closed position, and even in the closed position, the two-stage switching is performed by mechanical means, which will be described later.

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 closes the negative pressure chambers 8a, 9 of the power chambers 8, 9 when not in operation and is not excited.
a is opened to the atmosphere through the atmospheric holes 10b and 11b, and during the excited operation, the negative pressure passage 12 is opened to communicate the negative pressure chambers 8a and 9a to the vacuum tank 13.

16 is a battery with one end grounded, and a key switch 17 that closes during operation is connected to the battery 16.
and an accelerator switch 19, which opens when the accelerator pedal 18 is depressed and closes when the accelerator pedal is released, are connected in series. Furthermore, in contrast to the accelerator switch 19, there is an exhaust brake switch 20 that is manually opened and closed by the driver's selection, and a clutch switch 21 that opens when a clutch pedal (not shown) is depressed and closes when released.
and a neutral switch 23 which opens when the shift lever 37 is in the neutral position and closes when the shift lever 37 is in the shift position, which will be described later, are connected in series.

Excitation coil 1 of the first three-way solenoid valve 10
One terminal of 0a is connected between the accelerator switch 19 and the exhaust brake switch 20, and the other terminal is grounded. Further, one terminal of the excitation coil 11a of the second three-way solenoid valve 11 is connected to the neutral switch 23, and the other terminal is grounded.

A bypass passage 24 connects the upstream side and the downstream side of the intake shutter 4 of the intake passage 2, and is provided with an on-off valve 25 that opens in a specific operating state. One end of the excitation coil 25a of the on-off valve 25 is grounded, and the other end is connected to a starting switch 26, a warm-up switch 27, and a load switch 2, which are wired in parallel.
A connection wire is provided between the key switch 17 and the accelerator switch 19 via the key switch 17 and the accelerator switch 19.

The start switch 26 is a switch that is closed when the engine 1 is started, more precisely during cranking when the starter motor is operating, and for several seconds thereafter.The warm-up switch 27 is a switch that closes when the engine 1 is in an unstable combustion state. The load switch 28 is a switch that closes when the engine coolant temperature is below 80 degrees Celsius, for example, and the load switch 28 is a switch that closes when an extra load is applied to the engine 1, such as when the car cooler is activated or the loading platform of a dump truck is tilted. . When any one of these switches 26, 27, and 28 is closed, the excitation coil 25a of the on-off valve 25 is excited to open the on-off valve 25, and the bypass passage 24 is opened to reduce the throttle amount of the intake shutter device. decrease. As mentioned above, the reason for reducing the throttle amount of the intake shutter device when starting the engine, when the engine is cold, and when the engine is under load is to prevent the intake air from being insufficient at the time of starting, which will reduce the engine's startability. This is to prevent
This is because the combustion condition worsens due to insufficient intake air, causing half-misfire and emitting harmful unburned components.

Reference numeral 29 denotes a distribution type fuel injection pump, the control lever 29a of which is interlocked with the accelerator pedal 18, and the amount of fuel injected is determined by the amount of depression of the accelerator pedal 18 and the engine speed.

30 is an air cleaner.

Next, mechanical means for reducing the throttle amount of the intake shutter device when the engine brake is activated will be explained.

In FIG. 2, the intake shutter 4 is in the closed position when the accelerator pedal 18 is released.
A first protrusion 32a and a second protrusion 32 are attached to the rotation shaft 31 of
b and a lever member 32 having a third protrusion 32c.
is permanently installed.

A bolt 33 functioning as a stopper is screwed onto the first protrusion 32a and fixed with a lock nut 34. When the accelerator pedal 18 is released and the intake shutter 4 is in the closed position (see the dashed line in Figure 2), that is, during normal idling, the tip of the bolt 33 contacts the wall A and the intake air is removed. This restricts the shutter 4 to a predetermined opening degree.

A bolt 35 is also fixed to the second protrusion 32b with a lock nut 36 so as to protrude by a predetermined amount. The tip of this bolt 35 is connected to the shift lever 3.
Depending on the switching position 7, the opening of the intake shutter 4 is changed by coming into contact with a regulating member 38 that moves between the front position and the rear position.

Reference numeral 39 denotes a flexible cable, to which the regulating member 38 is attached to one end and the engaging member 40 is attached to the other end.

Reference numeral 41 denotes a shift select lever, which is connected to the shift lever 37 at one end thereof, and is configured to move in the select direction B (axial direction) or shift direction C (rotational direction) by switching the shift lever 37. There is.

Reference numeral 42 denotes an output member, whose base end is fixed to the shift select lever 41, and whose distal end is formed with an arc-shaped elongated hole 42a, into which the engagement member 40 is engaged. The output member 42 uses the axis (center line) of the shift select lever 41 as the center of rotation o. Further, the elongated hole 42a is curved toward the center of rotation, and the engagement position with the engagement member 40 changes depending on the state of the shift lever 37. That is, when the shift lever 37 is in the first, third, and fifth speeds, the engaging member 40 is in the s ₁ of the elongated hole 42a.
The elongated hole 42a is at the _s2 position when in second gear, fourth gear, and reverse, and is at the _s3 position intermediate therebetween when in neutral.

Therefore, since the engaging position of the engaging member 40 is different between when it is in neutral and when it is not, the regulating member 38 is adjusted depending on the engaging position.
It also moves back and forth between the rear position p ₂ and the front position p ₁ through the cable 39.

Reference numeral 43 denotes a return spring that constantly biases the regulating member 38 so that the regulating member 38 is at the front position _p1 . 44, 44 are guide members, and the engaging member 40
is restricted to be movable only in one direction, that is, in the w direction.

According to the above configuration, during idling operation when the engine is warmed up, the accelerator pedal 18
Since the pedal is released, the accelerator switch 1
9 is closed (at this time, the on-off valve 25 is not opened and the bypass passage 24 is closed). Then, the first three-way solenoid valve 10 is energized and opened, so the first three-way solenoid valve 10 is energized and opened.
A negative pressure passage 1 is connected to the negative pressure chamber 8a of the power chamber 8.
2, negative pressure is introduced from the vacuum tank 13, and the intake shutter 4 is rotated by the diaphragm 8b via the link mechanism 6 to the closed position (see the dashed line in FIG. 1). The throttle amount of the intake shutter device in this closed position is set to 100 mmHg or more and 400 mmHg or less (preferably 150 mmHg to 350 mmHg), thereby suppressing engine vibration and noise during idling operation. Here, the throttle amount of the intake shutter device is when the engine is idling, that is, when the engine is rotating at 600 rpm.
It is expressed by the intake negative pressure on the downstream side of the intake shutter, and it has been confirmed through experiments that the above range is desirable.

In addition, during normal driving, the shift lever 3
Since "7" is in the shift position and the engaging member 40 is in the _s1 or _s2 position of the long hole 42a of the output member 42, the restricting member 38 is located in the front position _p1 through the cable 39. To activate the engine brake, the accelerator pedal 18 is released in the above state.

Therefore, when the accelerator pedal 18 is released to activate the engine brake,
As in the case of idling, the accelerator switch 19 closes and negative pressure is introduced into the negative pressure chamber 8a of the first power chamber 8, so the intake shutter 4 attempts to rotate from the open position to the closed position. do.
However, the regulating member 38 is at the front position p ₁ as described above.
, the regulating member 38 comes into contact with the tip of the bolt 35 of the second protrusion 32b of the lever member 32, and acts as a stopper to stop the lever member 3.
Regulates the rotation of 2. As a result, the intake shutter 4 is placed in a slightly larger opening state (see the solid line in Figure 2) than the closed position during normal idling (see the one-dot chain line in Figure 2), and the first power chamber 8
is maintained against the force generated by the negative pressure in the negative pressure chamber 8a.

The position of the intake shutter during engine braking is as follows in normal operation when the on-off valve 25 is closed.
It is preferable that the aperture amount is set in a range of 15 mmHg or more and 75 mmHg or less.

Therefore, since the intake passage 2 is narrowed to a predetermined amount or more by the intake shutter 4, intake noise is reduced, and the engine brake is activated when the amount of intake air exceeds a predetermined amount. , engine braking performance does not deteriorate. This also applies when the exhaust brake is activated.

In addition, since the amount of throttle of the intake shutter device is changed by mechanical means, it has good responsiveness, high reliability, and can be manufactured at low cost.

In the above embodiment, whether or not the transmission is in the shift state is detected by the movement of the shift select lever 41, but it can also be detected from the movement of the transmission or other members linked to the transmission. Needless to say.

Either of the clutch switch 21 and the neutral switch 23 in the above embodiment opens during idling and disables the operation of the exhaust brake.
Alternatively, a speed switch may be used that opens when the engine is idling and closes when the engine speed is slightly higher than idling.

The accelerator switch 19, clutch switch 21, and neutral switch 23 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 19 can also detect the position of the control lever 29a of the fuel injection pump 29.

Note that the exhaust brake switch 20 of the above embodiment
is not necessarily required and may be omitted.

In the above <Embodiment 1>, the opening degree of the intake shutter 4 is increased to reduce the throttle amount of the intake shutter device during engine braking when the transmission is in the shift state, but in addition to this <Example 2> A similar effect can be obtained by providing a bypass passage and opening the bypass passage only when necessary, as shown in FIG. This is because narrowing down the intake passage 2 means reducing the effective passage cross-sectional area (opening area) of the intake passage 2.

<Embodiment 2> In FIG. 3, the intake passage 2 is formed to have a slightly larger cross-sectional area downstream of the portion where the intake shutter 4 is provided. Reference numeral 52 denotes a partition wall that connects the main passage 53 in which the intake shutter 4 is installed and the auxiliary valve 5.
4 and a bypass passage 55 provided with a bypass passage 55.

57 is a lever member, one end of which is connected to the auxiliary valve 54.
The other end is connected to a cable 39 having the same configuration as in the first embodiment.

Note that the overall configuration of the above example is the same as <Example 1>
Since it is the same as that, detailed explanation will be omitted and only the main parts will be explained.

Referring to the operation in the above embodiment,
When the transmission is in shift state, cable 39
Since the engine is moving forward, the auxiliary valve 54 rotates to the open position (see solid line in Figure 3), reducing the amount of throttle of the intake shutter device compared to during normal idling operation. In other words, the opening degree of the intake shutter 4 does not change, but the bypass passage 55 opens.
The effective cross-sectional area of the intake passage increases, and the amount of throttling decreases.

Furthermore, when the transmission is in the neutral state, the cable 39 is retracted, so the auxiliary valve 5
4 is in the closed position (see the dashed line in Figure 3). Therefore, the throttle amount of the intake shutter device becomes the preset throttle amount during idling operation.

In <Embodiment 1> and <Embodiment 2>, the intake shutter 4 is closed only when the accelerator pedal 18 is released (during idling), and the intake shutter is fully opened at other times. Since there is still a lot of excess air at low speeds, which are slightly higher than the idling engine speed (600r.pm), and the torque fluctuates, 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. 4, 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
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. 64
is a spring that constantly biases the lever member 32 in the direction in which the intake shutter 61 is in the closed position.

Note that the overall configuration of the above example is <Example 2>
Since it is substantially the same as that, the same reference numerals are used for similar components and detailed explanation thereof will be omitted.

As mentioned above, the present invention is designed to reduce the amount of throttle of the intake shutter device to warm up the engine, in the intake system of a diesel engine equipped with an intake shutter device that closes the intake shutter provided in the intake passage and throttles the amount of intake air during light loads. Intake negative pressure downstream of the intake shutter is 100mmHg when idling with the machine completed.
In addition to reducing the amount of throttle of the intake shutter device when the transmission is in the shift state, vibrations in the idling state,
Not only can noise be sufficiently reduced, but also intake noise can be effectively reduced during engine braking when the transmission is in a shifting state, especially during exhaust braking, and engine braking performance is also superior to conventional models. It has a great effect.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention; FIG. 1 is an overall configuration diagram of an intake system for an automobile diesel engine, FIG. 2 is a detailed view of the main parts of Embodiment 1, and FIG. 3 is a diagram of Embodiment 2. Detailed view of main parts, Figure 4 is Example 3
FIG. 5 is a diagram showing the characteristics of the accelerator pedal of the third embodiment. 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... battery, 17... key switch, 18... accelerator pedal, 19... accelerator switch, 20... exhaust brake switch,
21...Clutch switch, 23...Neutral switch, 24...Bypass passage, 25...Opening/closing valve, 25a...Excitation coil, 26...Starting switch, 27...Warming up switch, 28...Load switch, 29...Fuel injection pump, 29a...Control lever, 30...Air cleaner, 31...
...Rotation shaft, 32...Lever member, 32a...First
Protrusion, 32b...Second protrusion, 32c...Third protrusion, 33, 35...Bolt, 34, 36...Lock nut, 37...Shift lever, 38...Restriction member, 39...Cable, 40...Engagement member, 4
1...Shift select lever, 42...Output member, 42a...Long hole, 43...Return spring,
44... Guide member, 51... Intake passage, 52...
Partition wall, 53...Main passage, 54...Auxiliary valve, 55...
...Bypass passage, 56...Rotating shaft, 57...Lever member, 61...Intake shutter, 62...Accelerator pedal, 63...Link mechanism, 64...Spring.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In an intake system for a diesel engine equipped with an intake shutter device that closes the intake shutter and narrows the intake passage when the accelerator pedal is released. , the throttle amount of the intake shutter device is set so that the intake negative pressure downstream of the intake shutter is 100 mmHg or more during idling after the engine has been warmed up, and the throttle amount of the intake shutter device that has been set is set so that the transmission An intake system for an automotive diesel engine, characterized in that it is provided with a device that reduces air intake when in a shift state. (2) The intake system for an automotive diesel engine according to claim 1, wherein the shift state of the transmission is mechanically detected from a movable member interlocked with the transmission. (3) The intake system for an automobile diesel engine according to claim 2, wherein the movable member is a shift select lever. (4) The device that reduces the throttle amount of the intake shutter device is a bypass passage that communicates the intake passage between the upstream side and the downstream side of the intake shutter, and is provided with an opening/closing means that opens when the transmission is in a shifting state. An intake device for an automobile diesel engine as set forth in claim 1, 2, or 3 of the utility model registration claim. (5) The intake shutter device is configured such that the intake shutter is interlocked with the accelerator pedal, and the degree of opening of the intake shutter changes continuously according to the amount of depression of the accelerator pedal.Claim 4 of the Utility Model Registration Claim The intake system for the automobile diesel engine described above.