JPS6143951Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for controlling air in an exhaust passage connected to a combustion cylinder of an engine.

Normally, in order to ensure its output, the engine
The ventilation resistance of the exhaust pipe, muffler, etc. is kept low so that the exhaust pressure does not exceed the set value. However, when a car equipped with an engine requires braking force, rotational force due to inertia is applied to the engine from the car body side, and the engine operates as a pump to absorb this inertia. , also works as an engine brake. As a device capable of dealing with such a case, an exhaust brake is known, which actively closes the exhaust passage to increase the pumping loss of the engine. This exhaust brake uses a valve that opens and closes the exhaust passage by operating a switch, thereby controlling the exhaust pressure. On the other hand, means for improving the startability of an engine at low temperatures (hereinafter simply referred to as a low-temperature start assist device) is known. This throttles the exhaust path from the combustion tube, thereby reducing the amount of intake air, so that preheating is maintained for a long time even when the intake heater is turned off, and the intake air temperature is maintained high. Furthermore, since the exhaust pressure increases, the residual gas in the combustion cylinder increases, and the new temperature of the intake air mixed with this can be maintained high. This improves ignitability and improves engine startability. Moreover, since the exhaust pressure increases, the pumping loss of the engine increases, that is,
Friction increases and the increase in engine speed is suppressed, resulting in an abnormal increase in ignition delay at low temperatures (due to increased rotational speed and increased air volume), combustion blowout in cylinders with poor combustion conditions, etc. Inconveniences can be suppressed.

It is known that such a low-temperature start assist device is manually canceled upon completion of warm-up, or automatically canceled upon detection of water temperature. However, automatic release based on water temperature often takes a relatively long time (several minutes to tens of minutes), and while this is a reasonable measure against white smoke during startup, it is not recommended if you want to start driving immediately after startup. It wastes time and causes inconvenience.

Furthermore, when starting at a low temperature, it is generally necessary to fully depress the accelerator, and in particular, when the on-off valve of the cold start assist device is closed, it is necessary to keep the accelerator depressed even after the engine has started in order to overcome friction. be. For this reason, once the opening/closing valve is released, the engine speed N _E suddenly increases as shown in FIG. 1, which may be dangerous. To prevent this, you can adjust the amount of pressure on the accelerator, but this requires great skill.

The object of this invention is to provide a low temperature starting assist device that is easy to operate when ending warm-up operation.

The low-temperature starting auxiliary device according to this invention includes an on-off valve that can open and close the engine exhaust passage, a working gas receiving chamber to which working gas is supplied from a pressure supply source, and a working gas in the working gas receiving chamber that can open and close the on-off valve. A movable member that fluctuates in response to a working force is provided, and a means for regulating the flow of the working gas is installed in the path through which the working gas in the working gas receiving chamber is released to the atmosphere to slow down the flow of the working gas. The regulating means is configured to slow down the opening operation of the on-off valve.

In such a low temperature starting auxiliary device, the working gas flow regulating means acts to regulate the flow of the working gas in the atmosphere opening path. That is, when the on-off valve is opened, the working gas acting on the movable member in the working gas receiving chamber is released to the atmosphere, but at this time, the working gas flowing through the atmosphere opening path is kept at a predetermined rate from the start to the end of the flow. Requires flow time. Therefore, since the opening/closing valve slowly opens over a period of time, the accelerator can be appropriately released during this period, and the increase in engine speed can be suppressed to a low level.

This invention will be explained below with reference to the accompanying drawings.

FIG. 2 shows a diesel engine 2 to which a cold start assisting device 1 is attached as an embodiment of this invention, and its exhaust pipe 3. The low temperature starting assist device 1 is attached to an exhaust pipe 3 between an exhaust manifold 4 and a muffler 5, and includes a butterfly valve 6 disposed in an exhaust path R in the exhaust pipe 3, and a valve operating means 7 for operating the butterfly valve. and a low temperature start assist control means 8 and an exhaust brake switch 9 connected in parallel to the valve operating means.

As shown in FIG. 3, the butterfly valve 6 has a rotating shaft 10 pivoted across the center of the exhaust path R;
A valve body 11 integrated therewith, and an operating piece 12 fixed to one end of the rotating shaft 10 that protrudes from the exhaust pipe 3
It is formed by The valve operating means 7 includes an air cylinder 13 fixed to the exhaust pipe 3 so as to secure a fixed position, and a working gas receiving chamber (hereinafter simply referred to as receiving chamber) 14 in the air cylinder in the direction of its center line l. A piston 15 that is slidably fitted inside, an air supply pipe 17 that supplies high-pressure gas from the air tank 16 to the receiving chamber 14 via the first three-way solenoid valve 16, and an air supply pipe 17 that supplies the high-pressure gas from the receiving chamber 14 to the first three-way solenoid valve 16. Atmospheric opening road entrance 161
and an atmosphere release pipe 19 that opens to the atmosphere via the second three-way solenoid valve 18, which communicates with the atmosphere release port 181 of the second three-way solenoid valve 18 and another orifice side port 182;
It is also formed with a throttle valve 20 which is a means for regulating the flow of high-pressure gas. The pin 151 at the end of the piston 15 is loosely fitted into an elongated hole formed in the operating piece 12, and smoothly transmits the operating force of the linearly moving piston to the rotating operating piece 12. The piston 15 is held at the home position, the fully open position P1, by the elastic force of the return spring 21, and at this time, the valve body 11 maintains the fully open position (indicated by a chain line in FIG. 3). Furthermore, when the piston 15 receives high-pressure gas, it reaches the closed position P2 that forms a warm-up and exhaust brake clearance (hereinafter simply referred to as a minute clearance) (indicated by a solid line). First three-way solenoid valve 1
6 is turned on in response to a first actuation signal I1, which will be described later, and cuts off communication between the atmosphere opening passageway port 161 and the receiving chamber side port 162, and connects the air tank side port 163 and the receiving chamber side port 16.
2 and communicate with each other. It returns to its original state when it is turned off. The second three-way solenoid valve 18 receives a second actuation signal I2, which will be described later, and turns on, cutting off the communication between the atmosphere opening port 181 and the first three-way solenoid valve side port 183, and connecting the first three-way solenoid valve side port 183 and the orifice. It communicates with the side port 182. It returns to its original state when it is turned off. The throttle valve 20 receives high-pressure gas when the second three-way solenoid valve 18 is turned on, causes a manually set flow path cross section to act as an orifice, and discharges the high-pressure gas into the atmosphere at a set flow rate. As a result, the high pressure gas in the receiving chamber 14 gradually flows out, and the valve body 11
As shown in FIG. 4, the valve can be opened at a slow speed.

The low temperature starting auxiliary control means 8 is a power switch 801 that is turned on simultaneously with the operation of a starter (not shown).
, a water temperature detector 802 and a water temperature signal S0 emitted by this water temperature detector, and a warm-up time T corresponding to the water temperature signal S0.
A timer 803 keeps the power on for only one time, and at the on time of this timer, the first three-way solenoid valve 16
A low-temperature start auxiliary circuit 80 that outputs an actuation signal I1 and outputs a second actuation signal I2 to the second three-way solenoid valve 18 via a delay circuit 804 at the ON time of the timer.
5.

When the exhaust brake switch 9 is turned on, it sends out a first actuation signal I1 only to the first three-way solenoid valve 16, and at this time the second three-way solenoid valve 18 is kept in the off state. When the switch 9 is turned off, the high-pressure gas in the receiving chamber 14 is discharged into the atmosphere from the atmosphere release road side port 161 of the first three-way solenoid valve, through the atmosphere release pipe 19, and from the atmosphere release port 181 of the second three-way solenoid valve. The configuration is as follows.

The operation of the low temperature starting assist device 1 shown in FIG. 2 will be explained. First, the diesel engine 2 operates and the power switch 801 is turned on. Then, the water temperature signal S0 from the water temperature detector 802 is received, a warm-up time T1 corresponding to this signal is set in the timer 803, and the power is turned on. As a result, the low temperature starting auxiliary circuit 805 is turned on and sends the first and second actuation signals I1 and I2 to the first and second three-way solenoid valves 1 and 2.
6 and 18, both valves are turned on, high pressure gas from the air tank 16 is supplied to the receiving chamber 14, and the piston 15, which was at the fully open position P1, is moved to the closed position P2.
reach. At this time, the valve body 11 reaches the closed opening degree from the fully open opening degree, and a minute gap X1 is formed. This promotes warm-up, and eventually, after the warm-up time T1 has elapsed, the timer 803 is turned off. At this time, the first actuation signal I1 is immediately cut off, but the second actuation signal I2 remains on for a predetermined period of time due to the action of the delay circuit 804. Then, the first three-way solenoid valve 1
6 is turned off and the high pressure gas in the receiving chamber 14 flows to the atmosphere opening pipe 19 side. Furthermore, the second three-way solenoid valve 16 in the on state releases this high-pressure gas into the atmosphere via the throttle valve 20. At this time, the throttle valve 20 has been adjusted in advance, and the valve main body 11 performs a slow opening operation from the time t1 of the closed opening (minor gap X1) to the time t2 of the fully opened opening for a valve opening time T2 (= t2 - t1) (see Figure 4). At this time,
The accelerator (not shown) is fully opened, and the engine speed N _E increases as the valve body 11 is opened, but this increase is gradual and can be easily detected. Therefore, the maximum rotation speed N at full acceleration
By releasing the accelerator at time t3 before reaching _nax , a sudden increase in engine speed can be easily prevented (see the broken line in FIG. 4). After this, the diesel engine enters steady operation.

On the other hand, when the exhaust brake switch 9 is turned on in the diesel engine 2 in steady operation, only the first three-way solenoid valve 16 is turned on. Then, the piston 15 that received the high pressure gas moves to the closed position P2.
The valve body 11 maintains the closed opening degree. As a result, the exhaust pressure rises rapidly, but the diesel engine 2 is forcibly rotated by the inertia of the vehicle, causing a pump loss, which causes the exhaust brake to work. This exhaust brake is released by turning off the switch 9. That is, when the first three-way solenoid valve 16 is turned off, the high-pressure air in the receiving chamber 14 flows toward the atmosphere release pipe 19 and is rapidly released to the atmosphere through the atmosphere release port 181 of the second three-way solenoid valve that is in the off state.

In this way, the low temperature starting auxiliary device 1 shown in FIG.
is the minimum necessary warm-up time T according to the water temperature signal S0
Since the timer is set to 1, the vehicle can be driven quickly. Moreover, since the throttle valve 20 performs a slow valve opening operation over a valve opening time T2 (for example, 10 to 20 seconds), the opening timing of the valve body 11 can be easily detected by the rise in engine speed N _E , and when the accelerator is pressed. Any desired rotational speed N _E can be maintained by the return operation.

The low-temperature starting assist device 1 shown in Fig. 2 operates the valve body 11 in two positions: fully open and closed, but in addition to these two positions, there are three positions that can create an intermediate opening (used only for warming up). A butterfly valve (not shown) that can be opened and closed may also be used.

The low temperature starting assist device 1 shown in FIG. 2 used a butterfly valve 6, but instead of this, a slide gate type guillotine type valve (hereinafter simply referred to as a slide valve) 22 as shown in FIG. 5 was used. You can. The cold start assist device 24 in this case is similar to the cold start assist device 1 shown in FIG.
Since the structure is similar to that of , the same members are given the same reference numerals and their explanations will be omitted. Since the valve body 26 is reliably supported by the groove 25, the low temperature start assist device 24 can maintain the valve opening degree with high accuracy, and other effects are the same as the low temperature start assist device 1 shown in FIG.

The low temperature starting assist devices 1 and 24 shown in FIGS. 2 and 5 used high pressure gas as the working gas, but instead of this, negative pressure gas as shown in FIG. 6 is applied to the receiving chamber 27, The valve body 26 integrated with the negative pressure piston 28 may be operated to open and close. This low temperature starting assist device 29 is the low temperature starting assist device 24 shown in FIG.
Since the same members are included, the same members are given the same reference numerals and their explanations will be omitted. In addition, Bakyume Tank 3
After the negative pressure gas from 0 acts on the receiving chamber 27, the atmospheric air flowing into the throttle valve 20 slowly reduces the negative pressure level. Other functions and effects are similar to those of the low temperature starting assist device 24 shown in FIG.

Although the above-mentioned cold start assist devices 1, 24, and 29 use the throttle valve 20 that functions as an orifice as a means for regulating the flow of working gas, the present invention is not limited to this. For example, the low temperature starting auxiliary device 33 shown in FIG. 7 has a two-way solenoid valve 31 connected to the atmosphere opening pipe 19 (see FIG. In addition to sending out the signal I2, a pulse signal I3 is sent out from t1 at the start of the valve opening operation. At this time, as shown in Figure 8,
The two-way solenoid valve 31 is repeatedly turned on and off over time to gradually release the high-pressure gas in the receiving chamber 14 to the atmosphere. Note that the other structure is the same as that of the low temperature starting assist device 1 shown in FIG. The low-temperature starting auxiliary circuit 32 includes a controller and a pulse generator, and when these are off, the two-way solenoid valve 31 is opened to the atmosphere, and when on, the two-way solenoid valve 31 is intermittently opened by the pulse signal I3. opens and closes. Therefore, since the valve body 11 gradually reaches the full opening degree from the closed opening degree (micro gap X1), the valve opening time T2 during which this slow valve opening operation is performed
(See FIG. 4), by returning the accelerator (not shown), it is possible to suppress the increase in engine speed N _E . Although the orifice portion of the throttle valve 20 shown in FIG. 2 has the disadvantage of being easily clogged by small foreign objects, the opening of the two-way solenoid valve 31 shown here is large, so there is no such concern. Moreover,
The two-way solenoid valve 31 can reduce costs and has high reliability.

The low temperature starting assist device 33 shown in FIG. 7 used a three-way solenoid valve 16 and a two-way solenoid valve 31, but instead of this, two two-way solenoid valves 3 are used as shown in FIG.
It is also possible to form a cold start auxiliary device 36 using 4, 35. In this case, in order to keep the valve body 11 in the closed opening position, the first two-way solenoid valve 34 is turned on to open it, and the second two-way solenoid valve 35 is turned on and closed (the ninth
(shown as a solid line in the figure). Furthermore, in order to maintain the valve body 11 at the full opening degree, the first two-way solenoid valve 34 is turned off and closed, and the second two-way solenoid valve 35 is turned off and opened (indicated by a dashed line in FIG. 9). . Furthermore, in order to slowly open the valve body, the first two-way solenoid valve 34 is turned off and closed, and the second two-way solenoid valve 35 is turned on and pulse signal I is applied.
3 (see Figure 8) and opens intermittently. This case is also advantageous in terms of cost and reliability.

The low temperature starting assist device 33 shown in FIG. 9 uses a butterfly valve 6, but instead of this, a low temperature starting assist device 38 uses a slide valve 37 as shown in FIG.
may also be formed to obtain the same effect. Furthermore, as shown in FIG. 11, it is also possible to form a low temperature starting auxiliary device 41 using a three-way solenoid valve 39 and a two-way solenoid valve 40, using negative pressure gas as the working gas. In this case as well, when applying the pulse signal I3 to the two-way solenoid valve 40, the valve body 41 slowly opens the valve (see Fig. 8).
can do.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram of the valve clearance and engine speed when the conventional cold start assist device is released, and Fig. 2 is a schematic diagram of a diesel engine equipped with the cold start assist device as an embodiment of this invention. Figure 3 is an explanatory diagram of the operation of the butterfly valve used in the low-temperature start assist device as described above, Figure 4 is a characteristic diagram of the valve clearance and engine speed when the low-temperature start assist device is released, Figures 5 and 6 , Fig. 7, Fig. 9, Fig. 10
Figures 1 and 11 are schematic diagrams of cold start assisting devices as other different embodiments of this invention, and Figure 8 shows the valve clearance, two-way solenoid valve opening, and Each characteristic diagram of the signal is shown. 1, 24, 29, 33, 36, 38, 41...
Cold start assist device, 2...diesel engine,
6... Butterfly valve, 22, 37... Slide valve, 11, 26... Valve body, 14... Receiving chamber, 15
... Piston, 28 ... Negative pressure piston, 19 ...
Atmospheric release pipe, 20... Throttle valve, 31, 40... Two-way solenoid valve, 32... Low temperature starting auxiliary circuit, R... Exhaust path.

Claims (1)

[Scope of utility model registration request] An on-off valve that can open and close the exhaust passage of the engine, a working gas receiving chamber that is supplied with working gas from a pressure supply source, and a movable member that fluctuates in response to the operating force of the on-off valve from the working gas in this working gas receiving chamber. A means for regulating the flow of the working gas is installed in the path through which the working gas in the working gas receiving chamber is released to the atmosphere, and this means for regulating the flow of the working gas controls the opening operation of the on-off valve. A cold start assist device configured to slow down the speed.