JPH01300016A - Engine exhaust turbo-supercharger control device - Google Patents

Abstract

PURPOSE:To stabilize combustion and obtain improved fuel consumption by partially stopping exhaust turbo-supercharger operation when an engine is in a specified stop range and by cancelling the stop instruction when the engine is in a reduced load range although it is in the stop range. CONSTITUTION:In an engine equipped with two exhaust turbo-superchargers 31, 32 which supercharge intake gases using exhaust gas energy, means for stopping supercharger operation 41 is provided to stop the operation of an exhaust turbo-supercharger 32. Supercharger control means 92 is also provided to supply an output signal from means for detecting run status 91 which detects the running status of the engine. When the control means 92 has found that the engine is in a specified stop range, it controls the means for stopping supercharger operation 41 to stop the operation of the supercharger 32. When stop cancellation means 93 has found that the engine is in a reduced load range though it is in the stop range, it causes a supercharger stop instruction to be cancelled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine exhaust turbo supercharger control device;
In particular, the present invention relates to a device that includes a plurality of exhaust turbo superchargers and operates or stops some of the exhaust turbo superchargers depending on the operating state of the engine.

(Prior Art) Conventionally, as an exhaust turbo supercharger control device for an engine equipped with two exhaust turbo superchargers, for example,
As disclosed in Publication No. 8329, the turbines of the first and second exhaust turbo superchargers are provided in parallel in the exhaust passage, and the compressors of these two exhaust turbo superchargers are connected to the intake passage of the engine. At the same time, an exhaust cut valve is provided in the exhaust passage on the upstream side of the turbine of the second exhaust turbo supercharger,
When the engine is running at low speeds and under low load, the exhaust cut valve is closed and exhaust gas from the exhaust passage is intensively supplied to the turbine of the first exhaust turbo supercharger to ensure high boost pressure, while when the engine is at high speeds and under high load, A known system is known in which an exhaust cut valve is opened to supply exhaust gas from an exhaust passage to the turbines of two exhaust turbo superchargers to obtain an appropriate supercharging pressure while ensuring an intake flow rate.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional engine, the exhaust cut valve closes when the engine is running at low speed and low load, so the passage area of the exhaust passage becomes smaller, the exhaust resistance increases, and the exhaust gas pressure increases. Moreover, the capacity of the first exhaust turbo supercharger that operates at this time is smaller than the capacity of the exhaust turbo supercharger of an engine equipped with a single exhaust turbo supercharger, so the exhaust resistance increases even more. Exhaust gas pressure increases. Therefore, back pressure in the engine combustion system increases, dilution gas increases, combustion becomes unstable, and fuel efficiency worsens.

Also, for example, during sudden acceleration from a low-speed, low-load state, the exhaust cut valve suddenly opens while the second exhaust turbo supercharger is stopped, and the second exhaust turbo supercharger suddenly starts rotating. , oil is not immediately supplied to lubricated parts such as the bearings of the exhaust turbocharger, resulting in insufficient lubrication.

The present invention has been made in view of these points, and its purpose is to solve the problem that, in light load regions where combustion stability is a problem, some exhaust turbo superchargers should originally be stopped. The purpose of this operation is to lower the back pressure in the engine combustion system and to pre-operate the exhaust turbocharger to keep the exhaust turbocharger lubricated at all times.

(Means for Solving the Problem) In order to achieve the above object, the present invention basically stops the operation of a part of the exhaust turbo supercharger when the engine is in a predetermined stop region, and the engine All exhaust turbo superchargers are operated when the engine is in a light load area even if it is in a stop area.

Specifically, the solution taken by the present invention, as shown in FIG. 1, includes a plurality of exhaust turbo superchargers 31 and 32 that are provided in the engine and supercharge intake air using the energy of exhaust gas;
A supercharger operation stop means 41 that stops the operation of the exhaust turbo supercharger 32, an operating state detecting means 91 that detects the operating state of the engine, and an output of the operating state detecting means 91 that causes the engine to stop at a predetermined level. receiving the output of the supercharger control means 92 that controls the supercharger operation stop means 41 so that the operation of a part of the exhaust turbo supercharger 32 is stopped when in the range, and the operation state detection means 91; A stop release means 93 is provided for canceling the command to stop the exhaust turbo supercharger 32 by the supercharger control means 92 when the engine is in the light load range even if the engine is in the stop range.

(Function) With the above configuration, in the present invention, under the control of the supercharger control means 92, when the operating state detected by the operating state detecting means 91 is in the stop region, the supercharger operation stopping means 41 partially The operation of the exhaust turbo supercharger 32 is stopped and exhaust gas is intensively supplied to the normally used exhaust turbo supercharger 31 to ensure high supercharging pressure, while all the exhaust turbos are Exhaust gas is supplied to the superchargers 31 and 32, and appropriate supercharging pressure can be obtained while ensuring the intake flow rate.

In this case, the stop release means 93 releases the stop control of the exhaust turbo supercharger 32 by the supercharger control means 92 when the engine is in the light load region even if the engine is in the stop region, and all the exhaust turbo superchargers are Since exhaust gas is supplied to the feeders 31 and 32, exhaust resistance is reduced, back pressure in the engine combustion system is lowered, dilution gas is reduced, combustion is stabilized, and fuel efficiency is improved. become.

Moreover, as a result of this, a preliminary operation of some of the exhaust turbo superchargers 32 is performed, and the exhaust turbo superchargers 32 are always well lubricated.
2 starts operating, the lubricating part is lubricated with good followability.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows a 20-ta type rotary piston engine with an exhaust turbo supercharger equipped with an exhaust turbo supercharger control device according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a housing consisting of an intermezzo housing, a rotor housing, and a side housing. Two polygonal rotors 2, 2 are disposed within the housing 1. The three working chambers formed within the housing 1 undergo planetary rotation to sequentially perform intake, compression, explosion, expansion, and exhaust strokes.

The housing 1 has a primary port 3 and a secondary port 4 that supply fresh air to the working chamber during the intake stroke.
is provided. The housing 1 is also provided with an exhaust port 5 for discharging exhaust from the working chamber during the exhaust stroke.

And primary port 3 corresponding to each rotor 2 mentioned above.
An intake passage 10 is connected to the secondary port 4 at its branched end, and the intake passage 10 is opened to the atmosphere via an air cleaner 13. The intake passage 10 is divided into two intake passages 11 and 12, a first and a second intake passage. And the intake passage 1
At the downstream side of the merging part of 0, in order from the upstream side, an intercooler 14 for cooling the intake air, a throttle valve 15 for adjusting the intake air flow rate, and a surge tank 16 for mitigating the pulsation of the intake air. It is provided. Further, the intake passage 10 is provided with injectors 17 and 18 facing the primary port 3 and the secondary port 4 for injecting and supplying fuel, respectively.

Further, an exhaust passage 20 is connected to the exhaust boat 5.5. That is, one end of the exhaust passage 20 is branched into two exhaust passages 21 and 22, a first and a second exhaust passage.
Each exhaust passage 21, 22 is connected to two exhaust boats 5.
, 5.

This engine is provided with two exhaust turbo superchargers 31 and 32, a first and a second exhaust turbo supercharger. That is,
Turbines 31a and 3 of first and second exhaust turbo superchargers 31 and 32 are disposed in the first and second exhaust passages 21 and 22, respectively.
2a are provided respectively, and compressors 31b and 32b of first and second exhaust turbo superchargers 31 and 32 are provided in the first and second intake passages 11 and 12, respectively, to convert the energy of exhaust gas into This supercharges the intake air. Further, the first and second exhaust passages 21.22 are connected via a communication passage 33 on the upstream side of each exhaust turbo supercharger 31.32.

Further, in the second exhaust passage 22, an exhaust cut valve 41 is provided between the turbine 32a of the second exhaust turbo supercharger 32 and the communication passage 33. The system is designed to adjust the supply of exhaust gas to the That is, the exhaust cut valve 41 functions as a supercharger operation stop means for stopping the operation of the second exhaust turbo supercharger 32. Furthermore, the exhaust cut valve 41
The downstream second exhaust passage 22 and the communication passage 33 are connected through a leakage passage 42 . A leak valve 43 is provided in the leak passage 42 to adjust the supply of a small amount of exhaust gas to the turbine 32a of the second exhaust turbo supercharger 32. In addition, the communication path 33 and the first and second
Exhaust turbo supercharger 31. ．． It is connected to the exhaust passage 20 downstream of 32 through a bypass passage 44 . The bypass passage 4
4 is provided with a wastegate valve 45, which adjusts the bypass amount of pressurized air to improve the boost pressure characteristics. These six valves 41, 43, 45 are driven by pressure responsive actuators 46-48, respectively.

Furthermore, the first intake passage 1 in the second intake passage 12
An intake cut valve 51 is provided immediately upstream of the merging portion with 1. Further, the second intake passage 12 is provided with a relief passage 52 that bypasses the turbine 32a of the second exhaust turbo supercharger 32. A relief valve 53 is provided in the relief passage 52 to alleviate the pressure difference between the upstream side and the downstream side of the turbine 32a. These six valves 51 and 53 are driven by pressure-responsive actuators 56 and 57, respectively.

Further, a catalyst device 60 is provided downstream of the joining portion of the first and second exhaust passages 21 and 22 in the exhaust passage 20 to purify the exhaust gas.

Each of the actuators 46 to 48 and 56.
57 is controlled by a control unit 80.

Furthermore, 81 is an air flow sensor provided in the intake passage 10 to detect the intake air flow rate, 82 is a throttle sensor for detecting the opening degree of the throttle valve 15, and 83 is provided in the intake passage 10 to detect the intake pressure. 84 is a rotation speed sensor for detecting the engine rotation speed, 85 is a water temperature sensor for detecting the engine water temperature, and 86 is a pressure difference between the intake pressures on both sides of the intake cut valve 51. This is a differential pressure sensor for detection. Each of these sensors 81 to 86 is connected to a control unit 80, respectively.

Next, the operation of the control unit 80 is controlled by a third controller.
The explanation will be based on the flow shown in the figure. First, in step Sl, signals from each of the sensors 81 to 86 are input. Then, in step S2, it is determined whether or not the engine is in the stop region shown in FIG. 4, and in step S3, it is determined whether or not the engine is in the light load region shown in FIG. Here, the above-mentioned stop region corresponds to a region centered on a low speed, low load region of the engine, and a region where the intake air flow rate is low. Furthermore, the light load area is an area where the load is particularly low among the stop areas.

Then, when the engine is in the stop region and not in the light load region, that is, when the determination in step S2 is YES and the determination in step S3 is No, steps 84 to
In step S7, the operation of the second exhaust turbo supercharger 32 is stopped. That is, in step S4, the leak valve 43 is closed, and in step S5, the exhaust cut valve 41 is closed to stop the operation of the second exhaust turbo supercharger 32, and the exhaust gas is concentrated to the first exhaust turbo supercharger 31. supply to ensure high boost pressure, close the intake cut valve 51 in step S6 to prevent backflow of intake air from the intake passage 10 to the second intake passage 11, and open the relief valve 53 in step S7,
In operating conditions where the intake flow rate is low and the pressure is high, such as during deceleration, the pressure of the compressor 32b is relieved via the relief passage 52 to prevent surging of the compressor 32b.

On the other hand, when the engine is not in the stop region and the determination in step S2 is No, the second
The exhaust turbo supercharger 32 is activated.

That is, when it is determined in step S2 that the engine is not in the stop region, the leakage valve 43 is opened in step S8, and a small amount of exhaust gas is supplied to the second exhaust turbo supercharger 32 to perform a run-up of the turbine 32a. And step S9
The relief valve 53 is closed in step S+e, and the exhaust cut valve 41 is opened in step S+e. When the differential pressure between the intake pressures on both sides of the intake cut valve 51 becomes small, the intake cut valve 51 is opened in step S11 to start the second exhaust turbo supercharging. The engine 32 is operated and the intake air is supercharged by both the first and second exhaust turbochargers 31 and 32. This makes it possible to obtain an appropriate boost pressure while ensuring the intake air flow rate. Here, the reason why the relief valve 53 is closed before the exhaust cut valve 41 opens is that if the relief valve 53 is open when the exhaust cut valve 41 opens, the turbine 32a will idle and the rotation speed will suddenly increase. This is because the exhaust pressure fluctuates rapidly and the dilution gas in the engine changes greatly, causing combustion fluctuations.

Also, when the engine is in the light load region even if it is in the stop region, that is, the determination in step S2 and step S3
If both of the determinations are YES, step 88~
In step S11, the second exhaust turbo supercharger 32 is activated. As a result, both exhaust turbo superchargers 31.3
Since exhaust gas is supplied to 2, exhaust resistance is reduced,
The back pressure in the engine combustion system is lowered, reducing dilution gas, which stabilizes combustion and improves fuel efficiency.

Moreover, as a result of this, the second exhaust turbo supercharger 32 is pre-operated so that the second exhaust turbo supercharger 32 is always well lubricated, and this exhaust turbo supercharger 32 starts operating. In some cases, the lubricating portion is quickly lubricated with good followability, and good lubricity can be ensured.

Although it is possible to provide the exhaust cut valve 41 with the function of the leak valve 43, in this embodiment, the exhaust cut valve 41 and the leak valve 43 are each made separate so that the accuracy of the leak valve 43 function can be improved. is increasing.

Although not shown in the above flow, the operation of the waste gate valve 45 is also controlled by the control unit 80 according to the boost pressure.

In the above flow, step S1 constitutes the operating state detection means 91 that detects the operating state of the engine. Further, in step S2 and step S4 to step Sl+, the output of the operating state detection means 91 is received,
A supercharger control means 92 is configured to control the supercharger operation stop means (exhaust cut valve 41) so that the operation of a part of the exhaust turbo supercharger 32 is stopped when the engine is in a predetermined stop region. ing. Further, in step S3, the output of the operating state detection means 91 is received, and when the engine is in the light load region even if the engine is in the stop region, the supercharger control means 92 issues a command to stop the exhaust turbo supercharger 32. It constitutes a stop release means 93 for releasing the stop.

Although the above embodiments have been described with respect to a rotary piston engine, the invention is not limited thereto, and the present invention can also be applied to exhaust gas control devices for other types of engines, such as reciprocating engines.

(Effects of the Invention) As explained above, according to the engine exhaust turbo supercharger control device of the present invention, when the engine is in a predetermined stop region, the operation of a part of the exhaust turbo supercharger is stopped; Even if the engine is in the above-mentioned stop range, the exhaust turbo supercharger stop command is canceled when the engine is in the light load range, so the basic effect is that the intake air can be properly supercharged in the entire engine operating range. At the same time, the exhaust resistance is reduced in the light load range of the engine, the back pressure of the engine combustion system is lowered, and dilution gas is reduced, making it possible to stabilize combustion and improve fuel efficiency. This allows for good lubrication when the feeder starts operating.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 4 show examples, Figure 2 is a general schematic diagram, Figure 3 is a flowchart diagram showing operation control of the control unit, and Figure 4 is an explanatory diagram showing a stop region and a light load region. It is. 31... First exhaust turbo supercharger, 32... Second exhaust turbo supercharger, 41... Exhaust cut valve (supercharger operation stop means), 91... Operating state detection means, 92 ...Supercharger control means, 93... Stop release means. Figure 1 Figure 4 Figure 3

Claims (1)

[Claims] (1) A plurality of exhaust turbo superchargers are installed in the engine and supercharge intake air using the energy of exhaust gas, a supercharger operation stop means for stopping the operation of the exhaust turbo superchargers, and detect the operating state of the engine. an operating state detecting means for detecting the operating state; and receiving an output from the operating state detecting means, and controlling the supercharger operation stopping means so that the operation of a part of the exhaust turbo supercharger is stopped when the engine is in a predetermined stop region. receiving the output of the supercharger control means and the operating state detection means, and canceling the command to stop the exhaust turbo supercharger by the supercharger control means when the engine is in the light load region even if the engine is in the stop region. What is claimed is: 1. An exhaust turbo supercharger control device for an engine, characterized in that a stop release means is provided for controlling an engine exhaust turbo supercharger.