JPS61207827A - Variable capacity type supercharger - Google Patents

Abstract

PURPOSE:To improve reliability and durability of an engine by opening a guide vane when the intake air temperature is below a prescribed value and by reducing the aimed boost pressure when the intake air temperature is low. CONSTITUTION:A controller reads the number of engine revolution, engine load, and intake air temperature from the signals supplied from a revolution speed sensor 23, load sensor 24, and an intake temperature sensor 25. When the intake air temperature is over a prescribed value, an ordinary aimed boost pressure map is read, and when the intake air temperature is below the prescribed value, the aimed boost pressure in cold time when the boost pressure is low. When the actual measured boost pressure is higher than the aimed boost pressure, a nozzle vane 1 is opened, and when the actual measured boost pressure is lower than the aimed boost pressure, the nozzle vane 1 is throttled.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a variable capacity supercharger that can change the capacity of the supercharger by opening and closing movable guide vanes (movable nozzle vanes) provided in a turbine housing. Regarding improvements.

[Conventional technology]

Conventionally, a movable nozzle vane is installed inside the turbine housing of an exhaust turbo supercharger, and when the engine rotates at low speeds, this nozzle vane is rotated in the closing direction to reduce the capacity of the turbine, allowing the turbine wheel to rotate more easily and improving low-speed torque. When the engine speed increases, the nozzle vane is rotated stepwise or continuously in the fully open direction depending on the engine speed, increasing the capacity of the turbine and reducing the rotation of the turbine wheel. There is a variable capacity supercharger designed to improve fuel efficiency at high engine speeds.

Furthermore, as disclosed in Japanese Patent Application Laid-open No. 148619/1983, a movable nozzle vane (variable guide vane in the previous example) is provided on the compressor side of the exhaust turbo supercharger, and this is used to provide operating information for the engine and supercharger. There is also a supercharging device that is operated by the engine to obtain supercharging pressure (boost pressure) suitable for the operating condition of the engine.

However, such a variable capacity supercharger in which the variable guide vanes are provided on the compressor side has a disadvantage in that the variable effect is less than that in the case where the variable guide vanes are provided on the turbine side, making it impractical.

Among the variable capacity superchargers mentioned above, the one in which a movable nozzle vane is installed in the Yuichi bin housing is
As shown in FIG. 5 (al, (bl), the nozzle vane 1 provided in the nozzle part 2a of the turbine housing 2 is
Drive device 10 installed outside the turbine housing 2
By rotating the nozzle portion 2a, the flow velocity of the exhaust gas flowing out from the nozzle portion 2a to the turbine wheel 3 can be changed. A room in the casing 10a of the drive device 10 includes a thick wall portion 2 of the turbine housing 2.
a rotating shaft 11 that passes through b and connects to the nozzle vane 1;
A control lever 12 fixed to the other end, and a recess 13a provided on the inner circumference of the free end 12a of the control lever 12.
A drive mechanism for the nozzle vane 1 is provided, which consists of a control ring 13 that engages with the control ring 13 and a drive lever 14 that rotates the control ring 13.

The base of the drive lever 14 is connected to the casing 10a.
It is connected to a drive link 16 outside the casing 10a by a drive shaft 15 passing through the casing 10a, and when this drive link 16 is rotated by an actuator (not shown),
A nozzle vane 1 is configured to rotate within a turbine housing 2.

In the conventional variable capacity supercharger configured as above,
The rotation of the turbocharger changes depending on the environmental conditions, so if you match it in the standard condition, the rotation will increase depending on various conditions such as high altitudes and low atmospheric temperatures. The maximum rotation speed of the supercharger is lowered by more than 10,000 rotations.

However, when the intake air temperature is extremely low, the internal pressure of the explosion cylinder rises excessively due to a delay in ignition and an increase in the amount of intake air.
There is a problem that the reliability and durability of the engine are significantly impaired.

In addition, during rapid engine acceleration, it takes more than 3 seconds for the boost pressure to stabilize due to the turbocharger's response delay (turbo lag), and until the boost pressure stabilizes, the amount of intake air decreases, which worsens smoke. The disadvantage is that the engine output is insufficient. In particular, when overtaking a vehicle, it takes time for the output to appear after stepping on the accelerator, so
There is a problem in that the time spent driving in oncoming lanes is longer and there are many dangers.

[Purpose of the invention]

An object of the present invention is to solve the problems of the conventional variable displacement supercharger, to lower the target boost pressure when the intake air temperature is low, and to improve the reliability and durability of the engine. To provide a variable displacement supercharger equipped with an excellent control device capable of improving the acceleration by improving the rate of increase in boost pressure using movable guide vanes when the target boost pressure is not reached, such as during acceleration. That's true.

[Structure of the Invention] The variable capacity supercharger of the present invention that achieves the above object is equipped with an engine rotation sensor, a load sensor, and a boost pressure sensor, and when the boost pressure is lower than the target boost pressure, the movable guide vane in the turbine is activated. Aperture,
The present invention is characterized in that it includes a control device having a control characteristic of opening the guide vane when the target boost pressure is exceeded and when the intake air temperature is below a predetermined value.

〔Example〕

The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the configuration of two embodiments of the variable displacement supercharger of the present invention, and the same components as those of the conventional variable displacement supercharger will be described with the same numbers.

The nozzle vane 1 provided in the nozzle portion of the turbine housing 2 of the variable displacement supercharger T is controlled by a control lever 12 installed outside the turbine housing 2, similar to the device shown in FIG.
．． Control ring 13. Drive lever 14. By rotating by the drive device 10 equipped with the drive link 16 etc.,
It is configured such that the flow velocity of exhaust gas flowing out from the nozzle portion to the turbine wheel 3 can be changed.

The actuator 18 of the drive device 10 connected to the drive link 16 via the rod 17 is a hydraulic cylinder 18, and the actuator 18 of the drive device 10 is a hydraulic cylinder 18, and the lubricating oil sucked up from the oil pan 4 by the oil pump 5 is transferred to the oil feed valve 21. The nozzle vane 1 is opened and closed by driving the drive link 16 by moving the discharge pulp 22 in and out of the discharge pulp 22 and moving the rod 17 in and out of the hydraulic cylinder 18 .

The solenoids 21a and 22a for controlling the opening and closing of the oil feed valve 21 and the discharge pulp 22 are respectively connected to a control device 20 having a built-in microcomputer, etc., and this control device 20 also includes an engine rotation speed sensor. 23, an engine load sensor 24, an intake air temperature sensor 25, and a boost pressure sensor 26 installed in the surge tank 6a of the compressor 6 are connected, so that the operating state of the engine is input to the control device 20. ing. 7 is the intake manifold, 8 is the exhaust manifold,
9 indicates an air cleaner, and 19 indicates a battery.

In the memory of the control device for the variable capacity supercharger of the present invention configured as described above, target boost pressure characteristics with respect to the engine speed as shown in FIG. 2 are stored in accordance with the magnitude of the engine load, for example. The control device 20 outputs a signal to the oil feed valve 21 and the discharge pulp 22 based on the engine operating state inputted from each of the above-mentioned sensors and its characteristics, and controls the nozzle vane in the turbine housing 2 via the drive device 10. 1 to open and close. In this figure, the solid line shows the characteristics under normal conditions, and the broken line shows the characteristics under cold conditions (
(when the intake air temperature is low).

This control procedure will be explained using the flowchart shown in FIG.

When the engine starts, the control device 20 first steps
,■,■ rotation speed sensor 23. Load sensor 24. The engine speed, engine load, and intake air temperature are read based on the signal from the intake temperature sensor 25, and it is determined in step (2) whether the intake air temperature is equal to or higher than a specified value.

When the intake air temperature≧the specified value (YES), the process moves to step (2), and after reading the target boost pressure from the normal target boost pressure map (solid line in FIG. 2), the process moves to step (2). Also, when the intake air temperature is at the specified value (N
O) moves to step (2), reads the target boost pressure from the cold target boost pressure knob (broken line in FIG. 2), and then moves to step (2).

In this step (2), the actual boost pressure measured by the boost pressure sensor 26 and the target boost pressure are compared,
If the measured boost pressure≧target boost pressure (YES), the process moves to step (2), and if the measured boost pressure is less than the target boost pressure (NO), the process moves to step (2).

Furthermore, in step ■, it is determined whether or not the measured boost pressure = target boost pressure, and if the actual boost pressure is not the target boost pressure (No), that is, if the measured boost pressure is greater than the target boost pressure, the process moves to step ■. However, if the measured boost pressure is equal to the target boost pressure (YES), the process moves to step [phase].

When the process moves to step (2), that is, when the measured boost pressure is lower than the target boost pressure, the control device 20 outputs a signal to the oil supply valve 21 for 6 seconds to open it, and at the same time outputs a signal to the discharge pulp 22. output and close it, apply hydraulic pressure inside the hydraulic cylinder 18 to make the rod 17 protrude from inside the hydraulic cylinder 18, and throttle the nozzle vane 1 via the drive device 10 to increase the boost pressure by the supercharger T. . This state is the state at time T in FIG.

When this state continues for 11 seconds, the control procedure is again shifted to step (2) by the control device 20, and the same procedure as described above is performed. Then, in the next procedure, when the process moves to step (3), the oil feed valve 21 is opened again for t2 seconds, the discharge pulp 22 is closed, lubricating oil is introduced into the hydraulic cylinder 18, and the nozzle vane 1 is further throttled. Increase the boost pressure by the feeder T. The cycle from first performing control for t2 seconds to performing control for t2 seconds again is t1 seconds.

This procedure is performed by squeezing the nozzle vane L to
The boost pressure increases, and the process is repeated until the actual value exceeds the target boost pressure in step (■).

As a result of the above-described operation of the control device 20, when the measured boost pressure becomes equal to the target boost pressure at time T2, YES is obtained in step (2), so the process moves to step [phase].

In step [phase], the control device 20 controls the oil supply valve 2
1 and the discharge valve 22 are closed together, and the hydraulic cylinder 18 is closed.
The lubricating oil is not allowed to flow in or out, the original state is maintained, the nozzle vane 1 is maintained at the same opening degree, and the boost pressure of the supercharger T is not changed. This state continues as long as the measured boost pressure=target boost pressure, for example, from time T2 to time T3.

After this, at time T3, if the actual boost pressure becomes greater than the target boost pressure, the answer to step (2) is NO, so the process moves to step (2).

If the process has proceeded to step (2), the control device 20 outputs a signal to the oil supply valve 21 for t2 seconds to close it, and at the same time outputs a signal to the discharge valve 22 to open it, so that the inside of the hydraulic cylinder 18 is The hydraulic pressure is removed, the rod 17 is immersed in the hydraulic cylinder, and the nozzle vane 1 is opened via the drive device 10 to slow down the rotation of the supercharger T.

When this state continues for a time t2 seconds, the control procedure is again shifted to step (2) by the control device 20, and the same procedure as described above is performed. Then, in the next procedure as well, when the process moves to step (2), the control device 20 again controls the oil supply valve 2 for t2 seconds.
1 is closed, the exhaust valve 22 is opened to drain lubricating oil from the hydraulic cylinder 18, and the nozzle vane 1 is further opened to reduce the rotational speed of the supercharger T. The period during this period is the same as above.

Seconds.

This procedure is performed until the actual value of the boost pressure by the supercharger T≦the target boost pressure. (Time T4 indicates this state.) In this way, in the variable displacement supercharger control device of the present invention, the control device 20 always uses the actually measured boost pressure from the supercharger T to Compared with the target boost pressure read according to the air temperature, the actual boost pressure is always controlled to follow the target boost pressure according to the intake air temperature, so when the intake air temperature is low, the target boost pressure is lowered. In order to improve the reliability and durability of the engine, and to control the nozzle vane opening position based on engine rotation and engine load, a command is given to reduce the opening of the nozzle vane so that the boost pressure during acceleration, which is low, approaches the target boost pressure. By outputting , the rate of increase in boost pressure is improved, resulting in better acceleration.

In other words, when accelerating suddenly from a low-speed light load range, there was a limit to increasing the rate of increase in turbine rotation speed with conventional technology due to the inertia of the turbo impeller, etc., but with the present invention, the target boost pressure can be memorized. If the target boost pressure is not reached, the nozzle vanes are narrowed down to the maximum extent until the target boost pressure is reached. This causes the gas flow rate passing through the nozzle to suddenly increase and the turbine rotation to rapidly increase, thereby reducing turbo lag.

For example, calculation cycle 1. If the second is 1/20 second and the number of steps of the oil feed valve from fully open to fully closed is around 10, the gas flow rate passing through the nozzle will suddenly increase around 0.5 seconds, so compared to the conventional 3 seconds. The degree of turbo lag that has been affected is reduced by half with the variable displacement supercharger of the present invention.

〔Effect of the invention〕

As explained above, the variable capacity supercharger of the present invention is equipped with an engine rotation sensor, a load sensor, and a boost pressure sensor, and when the boost pressure is lower than the target boost pressure, the movable guide vane in the turbine is throttled.
By providing a control device having a control characteristic that opens the guide vane when the target boost pressure is exceeded and when the intake air temperature is below a predetermined value, the target boost pressure is lowered when the intake air temperature is low, and the engine In addition to improving the reliability and durability of the engine, when the target boost pressure is not reached, such as when the engine is accelerating, the nozzle vane can be narrowed to improve the rate of increase in boost pressure and improve acceleration. It has excellent effects.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the variable capacity supercharger of the present invention, and FIG. 2 shows the engine speed-target boost pressure characteristics stored in the control device of FIG. 1. line diagram,
FIG. 3 is a waveform diagram showing the opening/closing signals sent from the control device in FIG. 1 to the oil feed valve and the discharge pulp, and FIG. 4 is a flowchart showing the control procedure of the control device for the variable displacement supercharger of the present invention. FIG. 5 (al is a sectional view of a main part of a turbine housing showing the configuration of a nozzle vane drive device of a conventional variable displacement supercharger;
FIG. 5(b) is a sectional view taken along the line X--X of <al. 1... Movable nozzle vane, 10... Nozzle vane drive device, 18... Hydraulic cylinder (actuator),
20...Control device, 21...Oil supply valve, 22...
・Exhaust pulp, 23...Engine speed sensor, 24
...Engine load sensor, 25...Intake air temperature sensor, 26...Boost pressure sensor.

Claims (1)

[Claims] Equipped with an engine rotation sensor, a load sensor, and a boost pressure sensor, the movable guide vanes in the turbine are throttled when the boost pressure is lower than the target boost pressure, and when the target boost pressure is exceeded and the intake air temperature is below a predetermined value, the movable guide vanes are throttled. A variable displacement supercharger equipped with a control device that has control characteristics that open the valve.