JPS6221714Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a variable nozzle control device for a turbocharger.

Engines equipped with turbochargers increase engine output by receiving boost pressure that is greater than atmospheric pressure. This turbocharger is equipped with a compressor and a turbine.The turbine receives the energy of the exhaust from the engine, that is, the exhaust blowing energy and heat energy, and converts it into kinetic energy of rotation of the turbine, which outputs the turbine output. to occur. Furthermore, the compressor that receives the turbine output uses the turbine output as compressor driving force to compress the air supply and supercharge the engine. In such a turbocharger, when the engine is in a low speed rotation range, the flow rate of exhaust gas is small, and supercharging cannot be performed effectively, resulting in a decrease in engine shaft torque. To improve this, by narrowing down the turbine nozzle area, the kinetic energy that the exhaust gives to the turbine is increased, and the engine is supercharged in the low speed rotation range.
Means for increasing shaft torque are known.

By the way, the air supply pressure of the engine changes depending on the atmospheric pressure, and the air density is particularly low at high altitudes, and the mass flow rate of the air supply decreases, resulting in a reduction in the output of the engine. Moreover, there is a lack of oxygen in the engine cylinder, and if you drive with the same fuel injection amount as at low altitudes,
It also causes deterioration of smoke exhaust. This tendency also occurs in the case of turbo superchargers that use movable vanes to narrow down the turbine nozzle area and increase the kinetic energy that exhaust gas imparts to the turbine, just as in normal turbo superchargers. .

The object of this invention is to provide a variable nozzle control device for a turbocharger that allows the turbocharger to properly supercharge an engine at high altitudes.

The variable nozzle control device for a turbocharger according to this invention rotates a plurality of movable vanes that are pivotally connected to the turbine inlet side of the turbocharger, so that the turbine can be controlled according to the spacing between adjacent movable vanes. The variable nozzle drive section has a variable nozzle drive section that varies a nozzle area, and a variable nozzle control section that applies an output signal to the variable nozzle drive section so as to vary the kinetic energy that the turbine receives from the exhaust gas, and the variable nozzle control section is configured to control the engine. It is formed of a sensor that detects the rotation speed, a sensor that detects engine load, a sensor that detects atmospheric pressure, and a controller that is connected so that the detection signals of each of the above sensors are applied as input signals. , when the atmospheric pressure sensor detects an atmospheric pressure smaller than a set value and the engine load sensor detects a load larger than the set value, and the engine speed is in a low speed range, the turbine The nozzle area is maintained at a minimum value, and when the engine speed changes from the low speed range to the increasing direction, the turbine nozzle area is changed in the increasing direction.

In such a variable nozzle control device for a turbocharger, the controller operates based on the atmospheric pressure sensor and engine load sensor detecting that the engine load is high at high altitudes, and the engine speed changes within a predetermined range. It operates to maintain the turbine nozzle area below the value at low altitudes and strengthen supercharging.

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

FIG. 1 shows a diesel engine (hereinafter simply referred to as engine) 2 equipped with a variable nozzle control device (hereinafter simply referred to as variable nozzle control device) 1 for a turbocharger as an embodiment of this invention. This engine 2 has a compressor 4 of a turbocharger 3 connected to an air supply path I, a turbine 5 connected to an exhaust path E, and
It receives supercharging by the action of a rotating member consisting of a turbine wheel 6 and an impeller 7 housed in these. Further, a plurality of movable vanes 9 are pivotally attached to the turbine 5 on its inlet 8 side and are arranged so as to surround the outer periphery of the turbine wheel 6 (see FIG. 3). A variable nozzle drive section 10 of a variable nozzle control device 1 is connected to the movable vane 9, and a variable nozzle drive section 10 of a variable nozzle control device 1 is connected to the variable nozzle drive section.
1 is connected.

As shown in FIGS. 2 and 3, the variable nozzle drive unit 10 includes a movable ring 13 that simultaneously rotates each movable vane 9 around a pin 12, and a movable ring 13 that rotates the movable ring 13 along the turbine centerline l (the (See Figure 1) Actuator cylinder 1 that rotates around the
4, an air tank 15, and an on-off valve means 17 disposed on a pipe 19 that leads high-pressure air from this air tank to the inner chamber 16 of the actuator cylinder 14.
It is formed by The on-off valve means 17 includes a first solenoid valve 18 having one end communicating with the air tank 15 and the other end communicating with the inner chamber 16, and one end communicating with the inner chamber 16 and the other end communicating with the atmosphere opening 0.
The variable nozzle control unit 11 is connected to the second electromagnetic valve 20 that communicates with the second electromagnetic valve 20 . In addition,
The first solenoid valve 18 is closed when no power is supplied, and the second solenoid valve 20 is kept open so as to open the inner chamber 16 to the atmosphere when no power is supplied. The actuator cylinder 14 accommodates a piston 22 that is constantly pressed to the left by the elastic force of a spring 21, and this piston is held at a home position H (indicated by a broken line) when the interior chamber 16 is opened to the atmosphere. Piston 2 at this home position H
2, the rotary ring 13 at one end of the rod 23 connected thereto rotates most counterclockwise, and the plurality of movable vanes 9 interlocked with the rotary ring 13 As shown by the broken line in FIG. 2, the distance t between adjacent ones is maintained at the maximum. In this case, the turbine nozzle area is maintained at a maximum by the plurality of movable vanes 9.
Conversely, when the inner chamber 16 is sufficiently filled with high pressure air, the piston 22 is pushed to the right and comes into contact with the stopper 24. When the piston 22 is located at this pressurizing position Q, the rotary ring 13 rotates most clockwise, and the plurality of movable vanes 9 interlocked with this are shown by solid lines in FIG. In this way, the distance t ₀ between adjacent objects is kept as small as possible.
In this case, the turbine nozzle area is kept to a minimum by the plurality of movable vanes 9.

The variable nozzle control unit 11 uses a rotation speed detection sensor 25 that detects the rotation speed of the engine 2, a load detection sensor 27 that detects depression of the accelerator pedal as an engine load, and a Bourdon tube (not shown), for example. An atmospheric pressure detection sensor 28 that detects atmospheric pressure, a controller 29 that receives detection signals from these three sensors as input signals and sends output signals to the first and second electromagnetic valves 18 and 20, and a movable It is formed by a potentiometer 30 that detects the position of the ring 13 and feeds back a position signal to the controller 29 for input.
The controller 29 includes an engine rotation speed detection sensor 25, a load detection sensor 27, and an atmospheric pressure detection sensor 2.
8, which is configured to set the turbine nozzle area as shown in FIGS. 4 and 5.

The operation of the variable nozzle control device 1 shown in FIG. 1 will be explained. Here, it is assumed that the rotational speed of the engine 2 is divided into two regions A and B, which are a low rotational region and medium and high rotational regions, and highlands and lowlands are divided by a predetermined pressure value P ₀ .

First, in a lowland, if the atmospheric pressure Pa is higher than the set value P ₀ and the engine load L is lower than the set value L ₀ at this time, the controller 29 does not issue an output signal over the entire range of engine speed. This results in
The piston 22 is located at the home position H, and the turbine nozzle area becomes the maximum value _F2 , as shown by line a in FIG. Therefore, the exhaust gas from the engine 2 flows in such a manner that the kinetic energy received by the turbine wheel 6 is relatively gently applied thereto.

On the other hand, at low altitudes, the engine load L is at the set value.
When L ₀ is exceeded, the turbine nozzle area is maintained as shown by line b in FIG. That is, () When the engine speed is in the A range, an output signal is applied to the first and second solenoid valves 18 and 20, and the high pressure air in the inner chamber 16 drives the piston 2.
2 reaches the pressurizing position Q, and the turbine nozzle area becomes the minimum value F ₁ . Therefore, the exhaust gas from the engine flows in such a way that the kinetic energy received by the turbine wheel 6 is maximized, and the exhaust energy is maximized to rotate the turbine wheel 6 and the impeller 7, thereby increasing the engine torque.

() When the engine speed is in range B, the controller 29 has a potentiometer 30.
A position signal from the turbine is input as information corresponding to the turbine nozzle area. Thereby, the controller 29 calculates a state quantity (corresponding to the turbine nozzle area) determined by the engine speed, load, and atmospheric pressure set in the controller 29 in advance. In this case, as the engine speed changes from a low speed range to an increasing direction, the turbine nozzle area changes in an increasing direction along the characteristic shown by line b in FIG. 4. The difference between the state quantity and the position signal is determined, and if, for example, the turbine nozzle area has been expanded too much, the first solenoid valve 18 is opened and the second solenoid valve 20 is closed. The pressure increase is measured and the piston 22 is controlled to a predetermined position (a position between H and Q).
In addition, if the turbine nozzle area is too narrowed, the first solenoid valve 18 is opened and the second solenoid valve 20 is opened.
is opened to the atmosphere, the pressure in the inner chamber 16 is reduced, and the piston 22 is controlled to a predetermined position. in this way,
The turbine nozzle area is reduced in proportion to the decrease in engine speed. Therefore, the exhaust gas from the engine properly flows into the turbine wheel 6,
Exhaust energy can be extracted accurately and engine torque can be increased. In addition, near the engine speed reaching the maximum value (Nmax), the turbine nozzle area approaches the maximum value _F2 , and the first solenoid valve 18
is closed, the second electromagnetic valve 20 is kept open to the atmosphere, and the state is the same as when the load is low, that is, the a line and the b line intersect.

On the other hand, at high altitudes, when the atmospheric pressure Pa is lower than the set value _P0 , and at this time the engine load L is lower than the set value _L0 , the controller 29 does not issue an output signal over the entire range of the engine speed. In this case, the turbine nozzle area is maintained at the state shown by line a in FIG. 4, as in the case of a lowland.

On the other hand, at high altitudes, the engine load L is set to
When L ₀ is exceeded, the turbine nozzle area is maintained as shown by line c in FIG. That is, () When the engine speed is in the A range, in this case, the turbine nozzle area is operated by the controller 29 to maintain the minimum value F ₁ , which is the same as in the case of the lowland, and in this case, the effect is almost the same as that of the lowland. You can get

() When the engine speed is in range B, in this case, the potentiometer 30 operates in the same way as in the lowland case. And controller 2
9 calculates the difference between the position signal and the state quantity determined by the engine speed, load, and atmospheric pressure preset in the controller, and operates in the same way as in the lowland. However, the turbine nozzle area is set so that the amount of throttling is larger than in the case of lowlands.
Therefore, in region B, the turbine wheel 6 receives more kinetic energy from the exhaust gas than in lowlands. Therefore, even if the air density decreases at high altitudes, the supercharging effect can be increased accordingly, and a decrease in engine torque and deterioration of exhaust smoke can be prevented.

Note that the variable nozzle control device 1 shown in FIG.
At high altitude, the engine load L is the set value L ₀
If the value exceeds 1, the turbine nozzle area was set to change according to the characteristic shown by the c line in Fig. 4, but instead of this, the turbine nozzle area changes according to the characteristic shown by the d line in Fig. 4. You can also set it to do so. In this case, the turbine nozzle area is the minimum value
This widens the engine speed range in which _F1 is maintained, making it suitable for high-altitude situations where large engine loads are often applied. As described above, the present invention can strengthen supercharging when the engine load is large at high altitudes compared to low altitudes, prevent a decrease in the mass flow rate of air flowing into the engine, and prevent a decrease in engine torque.

[Brief explanation of the drawing]

Fig. 1 is a summary cut-away plan view of an engine equipped with a variable nozzle control device as an embodiment of this invention, Fig. 2 is a schematic configuration diagram of the same variable nozzle control device, and Fig. 3 is a diagram showing the same variable nozzle control device. FIG. 4 is an engine rotation speed-turbine nozzle area characteristic diagram, and FIG. 5 is a characteristic built in the controller shown in FIG. 2. Each table shows the relationship between turbine nozzle area, load, and atmospheric pressure. 1... variable nozzle control device, 2... engine,
3... Turbo supercharger, 5... Turbine, 8... Inlet, 9... Movable vane, 10... Variable nozzle drive section, 11... Variable nozzle control section, 25... Engine rotation speed detection sensor, 27 ...Load detection sensor,
28... Atmospheric pressure detection sensor, 29... Controller, t... Interval.

Claims (1)

[Scope of utility model registration request] A variable nozzle drive section that changes a turbine nozzle area according to the interval between adjacent movable vanes by rotating a plurality of movable vanes pivotally mounted on the turbine inlet side of a turbocharger; It has a variable nozzle control section that applies an output signal to the variable nozzle drive section so as to change the kinetic energy received from the exhaust gas, and the variable nozzle control section has a sensor that detects the engine rotation speed and a sensor that detects the engine load. , a sensor that detects atmospheric pressure, and a controller that is connected so that the detection signals of each of the sensors are applied as input signals, and the controller is configured to detect atmospheric pressure that is smaller than a set value by the atmospheric pressure sensor. is detected and the engine load sensor detects a load larger than the set value, and the engine speed is in a low speed range, the turbine nozzle area is maintained at a minimum value, and the engine speed is increased. A variable nozzle control device for a turbo supercharger, which has a built-in characteristic that changes the turbine nozzle area in an increasing direction when the turbine nozzle area changes from the low rotational speed range to an increasing direction.