JPS62276221A - Accelerator for turbo-charger - Google Patents

Abstract

PURPOSE:To improve the responsiveness of an engine by providing a reservoir tank for accumulating compressed air from a tank and a valve mechanism for supplying the compressed air inside the reservoir tank into between an exhaust port and a turbine. CONSTITUTION:A power switch signal, an exhaust temperature (t) and an engine revolution number (n) are read in from a power switch 43, an exhaust temperature sensor 42 and an exhaust air sensor 42 respectively into an electronic controller 41. When a throttle valve opening degree is more than the specified value, the exhaust temperature (t) is less than the specified value and the engine revolution number is less than the specified value, a solenoid valve 33 opens and the compressed air inside a reservoir tank 32 is supplied to an exhaust air passage 15. When the throttle valve opening degree is smaller than the specified value, or the exhaust air temperature (t) is higher than the specified value or the engine revolution number (n) is larger than the specified value, the solenoid valve 33 closes.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an acceleration device that improves the transient response of a turbocharger.

(Prior art) It is already known that a turbocharger is installed in an engine for the purpose of improving engine output.However, in the low speed range of the engine, the rotation of the turbocharger is slow due to the low flow rate of exhaust gas. It takes time for the supercharging effect of the intake air to appear after the accelerator pedal is pressed, and the response of the engine output is insufficient.

In order to improve this responsiveness, Japanese Patent Application Laid-Open No. 195023/1983 discloses a configuration having an air supply mechanism that supplies auxiliary air between the exhaust port of the engine and the turbine of the turbocharger depending on the operating state of the engine. Disclosed. In other words, this aims to increase the temperature of the exhaust gas by burning the unburned components in the exhaust gas using the auxiliary air, and also to increase the flow rate of the exhaust gas, thereby increasing the exhaust energy and increasing the turbine rotation speed. The auxiliary air is discharged from the air pump, controlled by the flow control valve, and supplied into the exhaust passage.

[Problem that the invention seeks to solve]

In the conventional device having the above configuration, the maximum flow rate of auxiliary air is determined by the capacity of the air pump, and therefore, in order to improve engine responsiveness, the capacity of the air pump must be made sufficiently large. However, there are restrictions on the weight and shape of the air pump due to mounting on the engine. In other words, the capacity of the air pump is limited, and the maximum flow rate of auxiliary air cannot be increased sufficiently.
There was a problem in that there was a certain limit to the responsiveness of the engine output.

[Means for solving problems]

In order to solve the above problems, a turbocharger acceleration device according to the present invention is characterized by having a reservoir tank capable of accumulating and holding compressed air discharged from a pump.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows a first embodiment of the invention. In this diagram,
A piston 12 is slidably housed in a cylinder bore 11 of the engine to form a combustion chamber 13, and a turbine 22 of a turbocharger 21 is located midway through an exhaust passage 15 that connects to an exhaust port 14 of the engine. port 1
A compressor 23 of a turbocharger 21 is provided in the middle of the intake passage 17 connected to the turbocharger 6 . As is well known, the turbine 22 and the compressor 'l! 3 are coaxially connected by a shaft 24, and the exhaust port 1
The turbine 22 is rotated by the exhaust gas discharged from the exhaust gas passage 15, which causes the compressor 2 to rotate.
3 rotates to supercharge intake air into the engine combustion chamber 13.

Exhaust passage 1 between exhaust port 14 and turbine 22
An air supply mechanism is provided to supply auxiliary air to 5. The air supply mechanism includes a pump 31 and a reservoir tank 32.
, a solenoid valve 33 , a throttle 34 , and a check valve 35 . The pump 31 may be either an electric type or a 1Hii type, takes in atmospheric air, compresses it, and pumps the compressed air to the reservoir tank 32. The reservoir tank 32 stores and holds this compressed air, and can hold air at a maximum pressure of 10 kg/Cm2, for example.

The solenoid valve 33 is of a normally closed type, and opens when the solenoid 36 is energized, releasing the compressed air in the reservoir tank 32 to the exhaust passage 15 side. The throttle 34 is provided between the electromagnetic valve 33 and the exhaust passage 15, and limits the flow rate of compressed air supplied to the exhaust passage 15. The check valve 35 is provided between the throttle 34 and the exhaust passage 15 and prevents compressed air from flowing backward from the exhaust passage 15. Note that the diaphragm 34 can be omitted.

Opening/closing control of the solenoid valve 33 is performed by an electronic control unit (ECIJ) 41 equipped with a microcomputer.

For this control, the ECU 41 includes an exhaust temperature sensor 42 provided near the exhaust port 14 of the exhaust passage 15, a power switch 43 and a rotation speed sensor 44 provided near the accelerator pedal (not shown). The detection signal is manually generated. Exhaust temperature sensor 42 and rotation speed sensor 4
4 detects the exhaust temperature and engine rotational speed, respectively, and the power switch 43 is turned on when the accelerator pedal is depressed by a predetermined amount or more, that is, when the opening degree of the throttle valve is more than a predetermined value. The ECU 41 controls the solenoid valve 33 to 0N- according to the accelerator opening, exhaust temperature, and engine speed.
OFF City; ■Wholesale.

FIG. 2 shows a control routine for the solenoid valve 33 by the ECU 41. This control routine is interrupted every 200 m5ec, for example.

In step 101, the power switch 43, the exhaust temperature t from the exhaust temperature sensor 42, and the engine rotation speed n from the rotation speed sensor 44 are read, respectively. Next, in step 102, it is determined whether the power switch is in the ON state or not.
If so, the process advances to step 106. In step 103, it is determined whether the exhaust gas '/At is less than or equal to a predetermined value T. If it is less than or equal to the predetermined value T, the process proceeds to step 104, and if it is higher than the predetermined value T, the process proceeds to step 106. In step 104, it is determined whether the engine speed n is less than or equal to a predetermined value No. If it is less than or equal to the predetermined value No, the process proceeds to step 105,
If it is larger than , proceed to step 106. Step 10
In step 5, the solenoid valve 33 is turned on, that is, opened, and in step 106, the solenoid valve 33 is turned off, that is, closed.

Therefore, the opening degree of the throttle valve is below a predetermined value, the exhaust temperature t is below a predetermined value T, and the engine speed fin is below a predetermined value N.
If it is less than o, step 101, 102, 103゜1
04 and 105, and the solenoid valve 33 opens. That is, if the electromagnetic valve 33 was closed due to the previous execution of this control routine, it is opened, and if it was opened due to the previous execution of the control routine, it is maintained in the closed state. Conversely, if the opening degree of the throttle valve is smaller than the predetermined value, the exhaust temperature [is higher than the predetermined value T, or the engine speed n is larger than the predetermined value NO, step 10
2. The process moves to step 106 from 103 or 104, and the solenoid valve 33 is closed. That is, if the solenoid valve 33 had been open until then, it will close, and if it had been closed until then, it will remain closed.

Therefore, when depressing the accelerator pedal in a low speed rotation range to rapidly accelerate the vehicle, if the exhaust temperature is low, the solenoid valve 33 opens and the compressed air in the reservoir tank 32 is supplied to the exhaust passage 15. .

As a result, unburned components in the exhaust gas are combusted, the exhaust gas temperature rises, and the flow rate in the exhaust passage 15 increases, resulting in an increase in exhaust energy. Therefore, the rotational driving force for the turbine 22 increases, and the rotational speed of the turbocharger 21 increases rapidly. At this time, as shown in FIG. 3, the compressed air stored in the reservoir tank 32 is discharged in the largest amount immediately after the solenoid valve 33 is opened, and the discharge flow rate decreases rapidly thereafter. That is, at low speeds, a large amount of auxiliary air is supplied to the exhaust passage 15 to improve the output torque of the engine, and then when the engine speed increases, the exhaust temperature rises, and the exhaust gas flow rate increases, the auxiliary air is supplied to the exhaust passage 15. Air supply is limited.

The engine is further accelerated, and the engine speed increases to a value greater than the predetermined value No. (When this happens, the wastegate valve (not shown) opens and the rotation of the turbocharger 21 is restricted, and the exhaust passage 15 is no longer connected to the exhaust passage 15. There is no need to supply auxiliary air, so the solenoid valve 33 is closed.

Furthermore, when the exhaust gas temperature rises and becomes higher than a predetermined value T, the solenoid valve 33 is closed to ensure safety.

In the first embodiment, the throttle 34 is set so that the flow rate characteristics of the auxiliary air are the best. For example, the throttle 34 is set so as to minimize the time required for the engine speed to reach a predetermined value No when the transmission is in 4th gear and full load acceleration is performed from a low speed rotation range.

Note that the exhaust temperature sensor 42 may be omitted, and the ECU 41 may control the air-fuel ratio and ignition timing in advance so that the exhaust temperature does not exceed a set temperature.

FIG. 4 shows a second embodiment of the invention. This second embodiment differs from the first embodiment in that it does not have an aperture 34 (FIG.), and the other configurations are the same as the first embodiment.

Thus, the function of the throttle 34 in the first embodiment is performed by the solenoid valve 33 in the second embodiment. That is, the solenoid valve 33 is controlled to open and close according to the engine operating state (engine speed change B) by the ECTL 41.
Changes the flow characteristics of auxiliary air. This is because the manner in which the engine speed increases in a full load acceleration state differs depending on the vehicle speed at the start of acceleration or the reduction ratio of the transmission.

FIG. 5 shows a control routine for opening and closing the Ti11ii valve 33 by the ECU 41, and this control routine includes, for example, two
Interrupt processing is performed every 00m5ec. Step 201~
204 are steps 101 to 1 in FIG. 2, respectively.
The process is exactly the same as step 04, and step 20
If a negative determination is made in any of steps 2, 203, and 204, steps 205 and 206 are executed, the solenoid valve 33 is closed, and the counter I is set to O. On the other hand, steps 202 and 203
, and 204, 1 is added to the counter I in step 207, and then in step 20 it is determined whether the value of the counter ■ is smaller than 2, that is, whether it is 1 or not.

When the counter I is 1, this means that the solenoid valve 33 has been closed so far, and the solenoid valve 33 has been opened by executing the current control routine. This means that it has started to accelerate. However, in this case, the process advances to step 209, where the engine speed n at this time is regarded as the rising speed N, and the sixth
The duty of the opening time of the solenoid valve 33 is determined with reference to the MA knob in the figure. That is, in FIG. 6, the duty (for example, indicated by D) corresponding to the rotational speed n on a straight line where n=N is found. And step 21
1, the solenoid valve 33 is opened based on this duty.

In step 208, when the counter (is 2 or more), this means that the solenoid valve 33 has already
This means that the valve is open. However, step 21
0, step 20 in the execution of the previous control routine.
Based on the rising rotational speed N determined by 9 and the current rotational speed n, the duty of the opening time of the solenoid valve 33 is determined from the map shown in FIG. That is, as shown in FIG. 6, the duty D is determined based on the momentary rotational speed n along the straight line S, for example. Then step 211
At this time, the solenoid valve 33 is opened based on this duty.

In this way, the amount of auxiliary air supplied to the exhaust passage 15 is determined by the engine speed at startup N and the momentary engine speed n.
It is determined based on this and is controlled to the optimum value according to the operating state of the engine.

In the first and second embodiments described above, in the no-load racing operation, even if the power switch 43 is in the ON state, this state hardly lasts for a long time, so the introduction of auxiliary air into the exhaust passage 15 is short. Thus, the rotational speed of the turbocharger 21 does not increase too much. However, in this case, when the engine speed exceeds the predetermined value No, the solenoid valve 33 is closed in step 104 or 204 of the control routine, and the rotation of the turbocharger 21 is suppressed.

〔Effect of the invention〕

As described above, according to the present invention, the flow rate of auxiliary air can be increased at the beginning of supply and then decreased.
When the engine is running at low speeds, the amount of auxiliary air supplied can be increased to improve engine responsiveness. Further, in this case, the capacity of the pump can be reduced, and therefore the entire device can be made lighter and smaller.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the first embodiment of the present invention, Fig. 2 is a flowchart of the control routine in the first embodiment, Fig. 3 is a graph showing the flow rate characteristics of auxiliary air, and Fig. 4 is a diagram showing the second embodiment. FIG. 5 is a flowchart of a control routine in the second embodiment; FIG. 6 is a graph showing a duty map of the opening time of a solenoid valve. 14... Exhaust boat, 15... Exhaust passage,
21...Turbocharger, 22...Turbine, 31...Pump, 3
2...Reservoir tank, 33...Solenoid valve, 34
... Throttle, 35... Check valve. Time Base 3 Solid 6- Calamity 2 Prisoner

Claims (1)

[Scope of Claims] 1. A turbocharger that rotates a turbine using exhaust gas discharged from an exhaust port to rotate a compressor and supercharge intake air to an engine, the turbocharger supercharging intake air to an engine. In a turbocharger accelerator having an air supply mechanism capable of supplying auxiliary air between an exhaust port and a turbine according to the conditions, the air supply mechanism is capable of accumulating and holding compressed air discharged from a pump and the pump. 1. A turbocharger accelerator comprising: a reservoir tank; and a valve mechanism that supplies compressed air in the reservoir tank between the exhaust port and the turbine. 2. The acceleration device according to claim 1, wherein the air supply mechanism has a throttle that limits the flow rate of compressed air. 3. The acceleration device according to claim 1, wherein the valve mechanism is a solenoid valve, which opens and closes under duty control to control the flow rate of compressed air. 4. The air supply mechanism supplies compressed air between the exhaust port and the turbine when the throttle valve opening is above a predetermined value, the exhaust temperature is below a predetermined value, and the engine speed is below a predetermined value. An accelerating device according to claim 1.