JPH01280635A - Supercharging pressure controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the output characteristics of an internal combustion engine from varying in vain and also to enable the free setting of torque characteristics by controlling supercharging pressure in a way that the mass flow of the intake air passing through the intake passage on the downstream side of a turbocharger is used as at least one control element. CONSTITUTION:The compressor 6 of an exhaust gas drive type supercharger 4 is faced to an intake passage 10 and a hot wire type, or the like, air flow sensor 22 is provided at the secondary intake passage 10-2 of the down stream side of the compressor 6. The mass flow of the intake air is detected by the air flow sensor 22 and supercharging pressure is controlled by a control means 28, in a way that the detected results are used as a control element, to make the output characteristics of an internal combustion engine 2 focus to an aimed value. The supercharging pressure control is conducted by controlling a relief valve 24-1 for releasing the supercharging pressure in the secondary intake passage 10-2 to the atmosphere or a relief valve 24-2 for releasing the supercharging pressure via a relief passage 32 to the first intake passage 10-1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a boost pressure control device for an internal combustion engine, and particularly to a system for controlling the boost pressure of an internal combustion engine. The present invention also relates to a boost pressure control device for an internal combustion engine that can prevent the occurrence of valleys in torque.

[Conventional technology]

As an internal combustion engine equipped with a supercharger that pumps air supply in order to improve output and fuel efficiency, there is an internal combustion engine constructed as shown in FIG. 6, for example. In Fig. 6, 2 is an internal combustion engine, 4
is an exhaust-driven supercharger. The exhaust drive type supercharger 4 consists of a compressor 6 and a turbine 8, and the compressor 6, which is provided facing an intake passage 10, is connected to an exhaust passage 12.
The intake air is rotated by a turbine 8 provided facing the compressor 6, and intake air taken in from an air cleaner 14 provided at the upstream end of the first intake passage 10-1 on the upstream side of the compressor 6 is fed. A throttle valve 18 is provided in the second intake passage 10-2 leading from the compressor 6 to the combustion chamber 16 of the internal combustion engine 2 on the downstream side.
This is provided. The intake air regulated by this throttle valve 1B is delivered to the combustion chamber 1 along with fuel from the unspoken fuel system.
It is supplied to G and burned. Exhaust gas is exhausted to the outside through an exhaust passage 12. Incidentally, the code 20 is Inktara, 2
2 is an air flow sensor.

In the internal combustion engine 2 provided with such a supercharger [4], if the supercharging pressure increases too much, the supercharger 4 and the internal combustion engine 2 will be damaged. Therefore, conventionally, when the boost pressure reaches a set value determined by outside air temperature, engine speed, etc.
The second intake passage 10 on the downstream side of the compressor 6 of the supercharger 4
A part of the supply air supplied under pressure is transferred to the atmosphere or to the upstream second intake passage 10-1 etc. by the relief valve 24.
Alternatively, a part of the exhaust gas from the first exhaust passage 12-1 on the upstream side of the turbine 8 of the supercharger 4 is transferred to the second exhaust passage on the downstream side using the waste gate valve 26.
A supercharging pressure control device for the internal combustion engine 2 has been proposed that prevents the maximum output from exceeding a target value by bypassing the exhaust passage 12-2 and controlling the supercharging pressure so that the maximum output does not exceed a set value.

Such a boost pressure control device opens and closes a wastegate valve according to the amount of intake air upstream of the compressor of the supercharger, bypassing a portion of the exhaust gas, and controlling the boost pressure to a set value (specially Publication No. 62-30285) or the supercharging pressure on the upstream side of the compressor of the supercharger]
The system controls supercharging pressure to a set value by opening and closing a gate valve to bypass part of the exhaust gas, and the above-mentioned Uniist gate
1 to 1. There is a system in which the supercharging pressure can be temporarily raised above a set value by relieving the supercharging pressure applied to an actuator to open and close a valve (Japanese Patent Application Laid-Open No. 131922/1982).

[Problem that the invention seeks to solve]

However, even if the supercharging pressure is controlled to the set value as described above, the output characteristics may vary depending on the operating conditions. For example, if the intake air temperature changes depending on the outside temperature or the cooling state of the ink cooler, a difference will occur in the output even if the boost pressure is the same. Particularly in cold regions, an excessive drop in intake air temperature may cause the maximum output to exceed the target value, resulting in an output exceeding the allowable strength of the internal combustion engine, which may eventually lead to damage. Alternatively, when the altitude changes due to traveling, a difference occurs in the output, and the output characteristics may exceed the target value depending on the set value of the supercharging pressure applied to the actuator to open and close the Uniis 1 to gate valves.

Further, as shown by the solid line in FIG. 5, even if the supercharging pressure is controlled to the set value, a valley may occur in the torque.

For this reason, even if the supercharging pressure is controlled to the set value, the output characteristics fluctuate unnecessarily and a valley occurs in the torque, resulting in a disadvantage that the driving performance is degraded.

[Purpose of the invention]

Therefore, an object of the present invention is to prevent the output characteristics of an internal combustion engine from fluctuating unnecessarily due to changes in intake air temperature, altitude changes, etc., and to maintain a target value under any operating conditions. Boost pressure control for an internal combustion engine that can obtain a certain output characteristic, increase the degree of freedom in setting the 1-lux characteristic, prevent the occurrence of valleys in torque, and thereby improve operating performance. The purpose is to realize the device.

[Failure to solve the problem]

In order to achieve this object, the present invention converges the output characteristics of the internal combustion engine to a target value by using at least one control factor the weight flow rate of intake air flowing through an intake passage downstream of a supercharger provided in the internal combustion engine. The present invention is characterized in that a control means is provided for controlling the supercharging pressure in order to increase the boost pressure.

[Effect]

According to the configuration of the present invention, the control means controls the supercharging pressure so as to converge the output characteristics to the target value using the intake air weight flow rate flowing through the intake passage on the downstream side of the supercharger as at least one control factor. By doing this, the boost pressure can be lowered so that the output of the internal combustion engine does not exceed the target value, regardless of changes in intake air temperature or altitude, and the boost pressure can be lowered so that the output of the internal combustion engine does not exceed the target value. can be raised.

〔Example〕

Next, embodiments of the present invention will be described in detail based on the drawings.

1 to 4 show an embodiment of the present invention.

In the drawings, parts that perform the same functions as in the prior art are given the same reference numerals and explained. That is, in FIG. 1, 2 is an internal combustion engine, and 4 is an exhaust-driven supercharger. The exhaust-driven supercharger 4 includes a compressor 6 and a turbine 8.
A compressor 6 provided facing the intake passage 10 is rotated by a turbine 8 provided facing the exhaust passage 12, and air is taken in from an air cleaner 14 provided at the upstream end of the first intake passage 10-1 on the upstream side of the compressor 6. This system pumps out the intake air. A second intake passage 10-2 extending from the compressor 6 to the combustion chamber 16 of the internal combustion engine 2 on the downstream side is provided with a throttle valve 18.

The intake air regulated by the throttle valve 18 is supplied to the combustion chamber 16 together with fuel from a fuel system (not shown).
be burned. Exhaust gas generated by combustion passes through the first exhaust passage 12-1, drives the turbine 8, and then flows into the second exhaust passage 1.
It is discharged to the outside by 2-2. Note that the reference numeral 20 is an ink cooler.

In the second intake passage 10-2 on the downstream side of the compressor 6 of the supercharger a, 4 provided in the internal combustion engine 2, an air flow sensor 22 such as a Bot wire type is provided. This air flow sensor 22 detects the weight flow rate Qa of intake air flowing through the second intake air aRLO-2.

The air flow sensor 22 is connected to the input side of the control stage 28. This control means 28 uses the intake air weight flow rate Qa detected by the air flow sensor 22 as at least one control factor, and controls the boost pressure to converge the output characteristics of the internal combustion engine 2 to a target value. Therefore, in this embodiment, a rotation speed sensor 30 for detecting the engine rotation speed Ne of the internal combustion engine 2 is connected to the input side of the control means 28, and a second intake passage 10-
Relief valve 24-1 that relieves the boost pressure of No. 2 to the atmosphere
is connected to the output side of the control means 28. or,
A relief valve 24-2 may be connected to the output side of the control means 28 to relieve the supercharging pressure of the second intake passage 10-2 to the first intake passage 1 (11) through the relief passage 32.These relief valves may be provided. 24-1 and 24-2 can be used alone or in combination.

As a result, the control means 28 controls the second and third
As shown in the figure, regarding the upper limit value q m a x of the intake air weight flow rate corresponding to the engine speed Ne, the engine speed range Ne (n) is divided into a plurality of parts (in this example,
Engine speed range divided into 16 Ne (1) - Ne (1
6) Intake air weight flow rate upper limit value q set corresponding to
max(n) (in this example, engine speed range N
The upper limit values qmax (1) to qmax (16) 7 set corresponding to e (1) to Ne (16) are compared with the detected intake air weight flow rate Qa, and the output characteristic left target value of the internal combustion engine 2 is determined. The relief valve 24
-1 and/or 24-2 to control boost pressure. The control means 28 also controls the fuel system/ignition system 3.
4 is also controlled to adjust the fuel injection amount and ignition timing.

Next, the operation will be explained according to FIGS. 2 and 3.

When the supercharger 4 is driven by the operation of the internal combustion engine 2, the intake air taken in from the air cleaner 14 is sent under pressure and cooled by the ink cooler 20, and the air flow sensor 22
The intake air weight flow rate Qa is detected. Further, the engine rotation speed Ne is detected by the rotation speed sensor 30. These signals of the intake air weight flow rate Qa and the engine speed Ne are manually input to the control means 28.

The control means 28 controls the fuel system/ignition system 34 based on these signals, and adjusts the fuel injection amount and ignition timing.

Based on these signals, the control means 28 determines the upper limit value q m a x (n) of the intake air weight flow rate set corresponding to the plurality of divided engine speed ranges Ne (n) and the detected intake air When the intake air weight flow rate Qa exceeds the upper limit value Gmax(n) (Q
a>qmax (n): YES) means that the relief valve 24-
By opening the relief valve 1 and/or the relief valve 24-2, the supercharging pressure can be lowered. On the other hand, if the intake air weight flow rate Qa is less than the upper limit value qmax(n) (
Qa > qrna x (n): No) means that the relief valve 2
The supercharging pressure can be increased by closing the relief valve 4-1 and/or the relief valve 24-2.

That is, the supercharging pressure is controlled by the intake air weight flow rate Qa so that the maximum output of the internal combustion engine 2 does not exceed the target value and so that the output can rise to the target value.

As a result, the output characteristics of the internal combustion engine 2 can be prevented from changing unnecessarily, and can be converged to the target value, regardless of changes in intake air temperature, altitude, etc. Therefore, the output characteristics that are the target values can be obtained under any operating conditions. Moreover, since the output characteristics of the internal combustion engine 2 can be converged to a target value by controlling the boost pressure, it becomes possible to freely set the torque characteristics. In addition, by partially increasing the torque as shown by the broken line in Figure 5, it is possible to prevent the occurrence of valleys in the torque and improve driving performance by 44%.
You can do two things. Furthermore, since the output characteristics can be converged to the target value, there is no need to take a safety factor in the design.

Note that the air flow sensor 22 is provided in the second intake passage 10-2 downstream of the ink cooler 20 compared to the conventional compressor.
This is because if it is provided in the first intake passages 10 to 1 on the upstream side of the nozzle 6, the actual intake weight flow rate cannot be detected, and
This is because accurate detection becomes impossible when the boost pressure is controlled by the relief valves 24-1 and/or 24-2. Therefore, relief valve 24-1 and/or 24-2
It must be provided on the upstream side of the sensor 22. Further, if the boost pressure is not controlled by the relief valves 24-1 and/or 24-2, there is no problem even if the air flow sensor 22 is provided upstream of the conveyor heater 6.

In this embodiment, the boost pressure is controlled by the relief valves 24-1 and/or 24-2, but as shown in FIG. Uniis 1 to be bypassed to -2 - gate valve 26
It is also possible to connect the LJ to the control means 28 and control the supercharging pressure so that the output characteristics converge to the target value using the Uniis I/Kate valve 26. In this case, the relief valves 24-1 and/or 24-2 and a waste gate are also possible.

However, it is preferable that the supercharging pressure be controlled by wastegate valves 24-1 and/or 24-2. This is because if the supercharging pressure is controlled by the Uniis I-gate valve 26, the rotational speed of the turbine 8 will be lowered, and as a result, the responsiveness of the return will be poor. Therefore, relief valve 24-1 and/or 2
If the control is performed in 4-2, even if the boost pressure is lost, the turbine 8
As soon as the relief valve 24-1 and/or 24-2 closes,
Responsiveness is good by returning to the original boost pressure.

In this embodiment, an internal combustion engine equipped with an exhaust-driven supercharger has been described, but as shown in FIG. It is obvious that the internal combustion engine 2 can be similarly implemented by providing a mechanically driven supercharger 4 that performs compression operation by being rotated while maintaining a small gap between the internal combustion engine 2 and the internal combustion engine 2.

〔Effect of the invention〕

As described above, according to the present invention, the control means controls the intake air weight flow rate flowing through the intake passage on the downstream side of the supercharger to be controlled at least as a control factor so as to converge the output characteristics of the internal combustion engine to a target value. By controlling the boost pressure, it is possible to lower the boost pressure so that the output characteristics of the internal combustion engine do not exceed the target value, regardless of changes in intake air temperature or altitude, and also to prevent the boost pressure from rising to the target value. You can increase the boost pressure to get more.

This prevents the internal combustion engine's output characteristics from fluctuating unnecessarily due to changes in intake air temperature, altitude, etc., and provides the target output characteristics under any operating conditions. be able to.

In addition, by controlling the boost pressure to converge the output characteristics of the internal combustion engine to the target value, it becomes possible to freely set the torque characteristics, and it is possible to partially increase the torque, thereby causing valleys in the torque. This can be prevented. As a result, driving performance can be improved. Furthermore, since the output characteristics can be converged to the target value, there is no need to take a safety factor in design, so manufacturing costs can be reduced.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention, FIG. 1 is a schematic diagram of a boost pressure control device, FIG. 2 is a block configuration diagram of a control means, FIG. 3 is a control flowchart, and FIG. 4 1 is a diagram showing an example of application to an internal combustion engine provided with an engine-driven supercharger. FIG. 5 is a diagram showing the relationship between 1-lux and supercharging pressure with respect to engine speed, and FIG. 6 is a schematic diagram of a conventional supercharging pressure control device. In the figure, 2 is an internal combustion engine, 4 is a supercharger, IO is an intake passage, 12 is an exhaust passage, 20 is an ink roller, 22 is an air flow sensor, 24-1 and 24-2 are relief valves, and 26
28 is a control means, and 30 is a rotation speed sensor. Patent Applicant: Suzuki Motor Co., Ltd. Agent Patent Attorney: Yoshi Saigo Mimuhae @Rinkyo

Claims (1)

[Claims] 1. Control for controlling supercharging pressure in order to converge the output characteristics of the internal combustion engine to a target value, with at least one control factor being the weight flow rate of intake air flowing through an intake passage on the downstream side of a supercharger provided in the internal combustion engine. A supercharging pressure control device for an internal combustion engine, characterized in that the device includes a means for controlling boost pressure.