JPS62168926A - Turbocharger - Google Patents

Abstract

PURPOSE:To maintain a clearance between a turbine housing and an exhaust turbine or between a compressor housing and a compressor to an optimum value, by gradually increasing a load of a turbocharger and wearing a combined material. CONSTITUTION:A combined member, with which the internal surface of a turbine housing is coated, uses a material serving for properly maintaining a clearance between the turbine housing and an exhaust turbine during operation. A load detecting means (b) detects a load of a turbocharger, and when the load is less than a predetermined value, a control means (c) calculates an output control value so as to obtain a turbocharger output in accordance with the predetermined value. When the load is in the predetermined value or more, the control means (c) calculates the output control value so that the predetermined value increases larger in stages as the time passes. An output control means (d) performs a control in accordance with the output control value from the control means (c). Accordingly, the combined member is gradually worn.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a composite member on the inner surface of a turbine housing or a compressor housing in order to reduce the clearance between the turbine housing and the exhaust turbine or the compressor housing and the compressor wheel. The present invention relates to a turbocharger that is coated to optimize this clearance during operation.

(Prior Art) As a conventional turbocharger, one shown in FIG. 3, for example, is known.

Figure 3 shows the structure of a relatively small turbocharger for automobiles, in which the exhaust turbine 1, which generates rotational force by receiving engine exhaust energy, and the compressor turbine 2, which pressurizes intake air, share a common turbine shaft. 3, the high-temperature, high-pressure exhaust gas is introduced into the exhaust turbine 1 through the scroll-shaped turbine housing 4, and the rotational force generated at this time drives the compressor wheel 2, which also forms a scroll compressor. Supercharging air is supplied to the engine via the housing 5.

The turbine shaft 3 is supported via a floating bearing 7 in a hollow center housing 6 located between the housings 4 and 5, and a thrust bearing is provided for positioning the shaft 3 in the thrust direction (horizontal direction in the figure). 8 is arranged on the compressor housing 5 side.

Lubricating oil introduced from the oil supply hole 9 in the upper part of the center housing 6 reaches the oil passage 10, passes through the small holes 10a and 10b, and lubricates the thrust bearing 8 and the floating bearing 7, respectively.

Further, the center housing 6 has its flange portion 6a fitted into the stepped opening 4a of the turbine housing 4, and the opening 4
It is fastened to the turbine housing 4 via a plurality of bolts 11 and a retainer plate 12 arranged around the a.

In such a turbocharger, in recent years, the clearance 1 between the exhaust turbine 1 and the turbine housing 4 has been increased.
In order to improve the efficiency of the turbocharger by reducing the clearance 13, a composite member 14 is coated on the inner surface of the turbine housing 4, which is prepared in advance and has a thinner inner surface, so that the clearance 13 is close to zero, and the operation of the turbocharger is improved. Attempts have been made to wear out the composite member 14 using the exhaust turbine 1 during the process, and finally set the clearance 13 to an optimum value.

Next, a conventional turbocharging pressure control method for a turbocharged engine will be described.

With the development of electronic technology, so-called electromagnetic control valves have become known, which accurately control operating pressure, fuel amount, etc. by duty-controlling electromagnetic valves. Used for control, etc. here,
As a device for controlling the boost pressure of a turbocharger, for example, as shown in FIG. 4, a wastegate valve 23 is installed in a passage 22 that bypasses the exhaust turbine 1 of the turbocharger.
There is a system that maintains the boost pressure at an appropriate value by controlling the amount of exhaust gas introduced from the engine 24 into the exhaust turbine 1.

The discharge pressure of the intake compressor 2 regulated to a predetermined pressure by the electromagnetic control valve 27 is introduced from the pressure passage 26 into the pressure chamber of the diaphragm actuator 25 that drives the wastegate valve 23.
is a pulse signal from the control circuit 33 based on the detected values from the throttle sensor 28, rotation speed sensor 29, knock sensor 30, pressure sensor 32 of the intake passage 31, etc.
The waste gate valve 23 is duty-driven so as to have a predetermined opening degree.

Therefore, the amount of exhaust gas introduced into the exhaust turbine 1 is set according to the duty value of the electromagnetic control valve 27, and by controlling the rotation of the turbocharger, the supercharging pressure adapted to the engine operating conditions is maintained. , it is possible to perform optimal supercharging (Japanese Patent Application Laid-Open No. 57-1570)
(See Publication No. 16, etc.)

(Problems to be Solved by the Invention) However, in such conventional turbochargers, the boost pressure control device simply controls the boost pressure according to the engine load, so the turbine If the turbocharger is operated under high load before the clearance between the housing and the exhaust turbine reaches an appropriate value, it will be forced to rotate even though the clearance is a small value that is not suitable for high rotation. As a result, the exhaust turbine becomes unable to rotate, and the composite member peels off more than necessary, resulting in a reduction in the performance of the turbocharger.

(Means for Solving the Problems) The present invention has been made to solve these problems, and as shown in FIG. A turbocharger body a whose inner surface is coated with a composite material to optimize the clearance between the turbine housing and the exhaust turbine or the compressor housing and the compressor wheel during operation, and a load detection means for detecting the load on the turbocharger. When the load of the turbocharger is less than a predetermined regulation value, the output control value is calculated so that the turbocharger output corresponds to the predetermined regulation value, and when the load exceeds the predetermined regulation value, the predetermined regulation value is changed over time from the beginning. control means C for controlling the turbocharger output by calculating an output control value so as to gradually increase the turbocharger output according to the regulation value; and an output operation means d for operating the.

(Function) In the present invention, the output of the turbocharger is regulated to a predetermined value, and this regulated value increases stepwise as time passes. The composite material coated on the inner surface of the turbine housing or the compressor housing is thus gradually worn away, so that the clearance between the turbine housing and the exhaust turbine or the compressor housing and the compressor wheel is maintained at an optimum value.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 is a diagram showing an embodiment of the present invention.

The turbocharger in this embodiment is shown in Figures 3 and 4.
Similar to the conventional example shown in the figure, the inner surface of the turbine housing 4 is coated with a predetermined composite member 14 to optimize the clearance 19 between the turbine housing 4 and the exhaust turbine 1 during operation. used.

In this embodiment, the pressure sensor 32 constitutes a load detection means, and the exhaust bypass passage 22, the wastegate valve 23, the actuator 25, and the electromagnetic control valve 27 collectively constitute an output operation means. In addition, the control circuit 3
3 has a function as a control means.

The operation will be explained below based on FIG.

FIG. 2 is a flowchart showing a control program for controlling the supercharging pressure of the turbocharger, and P1 to P13 in the figure
indicates each step. Note that this program is repeatedly executed, for example, at predetermined time intervals.

First, read the control regulation value P of the boost pressure using Pl, and
Read the compressor outlet pressure Pt at z. Then, P
3, the current compressor outlet pressure P2 is compared with the regulation value P1. The regulation value PT is set to increase in stages according to the elapsed time from the initial startup of the turbocharger (meaning from the time it was shipped as a product), and is set to appropriately control the degree of wear of the composite member. This has been taken into consideration so that the Therefore, the regulation value P
, is set lower than the final regulation value when the turbocharger is initially started.

When Pz<Pl, proceed to P4. In P4, the duty value of the electromagnetic control valve 27 that controls the boost pressure of the turbocharger is calculated, and in P5, the control duty value obtained in P4 is output to the electromagnetic control valve 27, and P2≧P,
Wait until it becomes.

Then, when P2≧PT at P3, the timer flag FLAG is determined at P6. The timer flag FLAG indicates the activation status of the timer that counts the elapsed time of operation. When FLAG = 1, it indicates that the timer is activated, and when FLAG = 0, it indicates that the timer is not activated. represent.

When FLAG=O in P6, start the timer with Pl, set the timer flag FLAG with P8, and proceed with P9.
Proceed to. In addition, when FLAG=1, it is determined that the timer has already started and this routine is being repeated, and it continues to P9.
Proceed to. In P9, the elapsed time T after Pz becomes equal to or greater than PT is calculated. This is determined by integrating the count value of the timer. Next, Plo sets the elapsed time T to a predetermined value T.
.

Compare with. When T<To, the process proceeds to P4, and then proceeds to P5 as described above. Pl at this time is the same as the value given by Pl. T≧T in PLO.

If , proceed to pH. For pH, a predetermined value α is added to PT. That is, the boost pressure control regulation value P is increased.

Next, the timer flag FLAG is reset in Pl2, and the timer is cleared (T=0) in Pl3, and the timer flag FLAG is reset in Pl3.
Then, the control duty is calculated based on the increased Pl and outputted to the electromagnetic control valve 27. In this way, the compressor outlet pressure P2 is controlled to the regulation value P, and this regulation value P7 gradually increases as time passes from the beginning of operation.

In other words, the load on the turbocharger gradually increases. Therefore, the composite member 14 coated on the inner surface of the turbine housing gradually wears out, and the clearance 13 between the turbine housing 4 and the exhaust turbine 1 is maintained at an optimum value. As a result, unlike in the past, the exhaust turbine 1 does not become unrotatable, and it is possible to suppress unnecessarily peeling off of the composite member 14 and prevent the performance of the turbocharger from deteriorating.

In this embodiment, the compressor outlet pressure P2 is detected as the load on the turbocharger; however, the load on the turbocharger is not limited to this, and the turbocharger rotation speed, engine intake air flow rate, etc. may be used alone or in combination to detect the load on the turbocharger. You can do it like this.

Further, in this embodiment, a case has been described in which the inner surface of the turbine housing 4 is coated with the composite member 14, but the same effect can be obtained even when the inner surface of the compressor housing 5 is coated with the composite member 14.

(Effect) According to the present invention, the clearance between the turbine housing and the exhaust turbine or the compressor housing and the compressor turbine can be optimally maintained by gradually increasing the load on the turbocharger and wearing out the composite member. I can do it.

As a result, it is possible to provide a high-performance turbocharger with optimum clearance.

[Brief explanation of drawings]

Fig. 1 is a basic conceptual diagram of the present invention, Fig. 2 is a flowchart showing a control program of an embodiment of the present invention, Fig. 3 is a sectional view of a conventional turbocharger, and Fig. 4 is a conventional turbocharged internal combustion engine. It is a diagram showing a control device of an engine. ■...Exhaust turbine, 2...Compressor wheel, 4...
Turbine housing, 5... Compressor housing, 13...
... Clearance, 14 ... Composite member, 32 ... Pressure sensor (load detection means), 33 ...
...Control circuit (control means).

Claims (1)

[Scope of Claims] a) A turbocharger body in which the inner surface of the turbine housing or the compressor housing is coated with a composite member to optimize the clearance between the turbine housing and the exhaust turbine or the compressor housing and the compressor wheel during operation. b) load detection means for detecting the load on the turbocharger; c) calculating an output control value so that the turbocharger output corresponds to the predetermined regulation value when the load on the turbocharger is less than the predetermined regulation value; control means for controlling the turbocharger output by gradually increasing the predetermined regulation value as time passes from the beginning when the regulation value exceeds the regulation value, and calculating an output control value so that the turbocharger output corresponds to the regulation value; d) A turbocharger characterized by comprising: output operating means for operating the output of the turbo'charger based on an output control value from the control means.