JPS6019921A - Supercharged pressure control device for turbo-supercharger - Google Patents

Abstract

PURPOSE:To aim at protecting an engine, by lowering the supercharged pressure when the cooling function of an intercooler drops to prevent the occurrence of knocking. CONSTITUTION:If the difference between the temperature T1 detected by a first temperature sensor 10 and the temperature T2 detected by a second temperature sensor 11, that is, the temperature difference across an intercooler 9 is below, for example, 10 deg.C, which shows that the intercooler 12 is in an abnormal condition, and therefore the supercharged pressure is lowered to turn on a warning lamp 18. In the case of that the temperature difference (T1-T2) is, for example, from 10 to 35 deg.C, the intercooler 9 operates in the normal condition. When the temperature difference (T1-T2) is above, for example, 35 deg.C the cooling capacity of the intercooler 9 is sufficient so that the supercharged pressure is raised.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a boost pressure control device for a turbocharger equipped with an intercooler that cools air discharged from a compressor.

BACKGROUND ART In order to improve the supercharging efficiency of a turbocharger, an intercooler is sometimes provided to cool air supercharged by a compressor. However, when a lever intercooler is installed, the supercharging pressure can be increased, and effects such as advancing the ignition timing and lowering the air-fuel ratio can be obtained. However, if the function of the intercooler becomes insufficient for some reason, these effects cannot be fully demonstrated. For example, if the air is not cooled well when the boost pressure is high, the engine is likely to knock.

Purpose of the Invention In view of the above points, the present invention provides a boost pressure control for a turbocharger that is capable of reducing the boost pressure to prevent knocking and protect the engine when the cooling function of the intercooler decreases. This was done for the purpose of providing equipment.

Composition of the Invention A boost pressure control device according to the present invention includes first and second temperature sensors that respectively detect temperatures before and after an intercooler;
A bypass valve that can open and close a passage that bypasses the turbine of the turbocharger, and when the difference between the temperatures detected by the first and second temperature sensors is less than a predetermined value, the bypass valve is opened to reduce the boost pressure of the turbocharger. The invention is characterized in that it includes a control section that controls the operation.

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

FIG. 1 shows an intake and exhaust system of an engine equipped with an apparatus according to an embodiment of the present invention. In this figure, a turbocharger 4 is provided midway through an intake pipe 2 and an exhaust pipe 3 extending from an engine body 1. The turbocharger 4 includes a turbine wheel 5 housed in the exhaust pipe 3, a compressor wheel 6 provided in the intake pipe 2, and both wheels 5, 6.
It has a shaft 7 that connects the. turbine wheel 5
is rotationally driven by the exhaust gas flowing in the exhaust pipe 3,
The compressor wheel 6 is rotated via the shaft 7. The compressor wheel 6 supercharges the air sucked into the intake pipe 2 through the air cleaner 8 to the engine main body l.

An intercooler 9 is disposed within the intake pipe 2 between the compressor wheel 6 and the engine body 1 to cool the air supercharged by the turbocharger 4. First and second temperature sensors 10 and 11 are provided upstream and downstream of the ink cooler 9, respectively. That is,
The temperature of the air flowing into the intercooler 9 is detected by the first temperature sensor 1l'1°, and the temperature of the air that has passed through the ink cooler 9 and has been cooled is detected by the second temperature sensor 11.

Signals indicating these temperatures are input to an engine control unit (ECU) 20 for the intercooler.

A first pressure sensor 12 is provided near the first temperature sensor 10 , and a second pressure sensor 14 is provided near the second temperature sensor 11 and upstream of the throttle valve 13 . The pressures before and after the ink cooler 9 are detected by these pressure sensors 12 and 14, and this pressure signal is input to the intercooler IECU 20.

A throttle valve sensor 15 is provided outside the intake pipe 2 to detect the opening degree of the throttle valve 13 in conjunction with the shaft of the throttle valve 13, and a third temperature sensor 16 is provided immediately downstream of the air cleaner 8. provided. Further, a knock sensor 17 is attached to the engine body 1, and the output of this sensor 17 is processed in a knock ECU 21 to determine the amount of retardation of knock control. A signal indicating the amount of retardation is input to the intercooler ECU 20 together with the output signals of the sensors 15 and 16.

The intercooler ECU 20 performs processing to be described later based on the above signals, turns on the warning light 18, and outputs a signal to the supercharging pressure control tall p and cu 22. The boost pressure control ECU 22 drives the actuator 30 to open and close the bypass valve 31, thereby controlling the boost pressure of the turbocharger 4. That is, the bypass valve 31
It opens and closes a passage 32 that communicates the upstream and downstream sides of the turbine wheel 5. When this valve 31 opens,
The amount of air flowing into the turbine wheel 5 decreases, and the boost pressure decreases. The actuator 30 is operated by selectively guiding either the negative pressure or the atmospheric pressure generated in the intake pipe 2 using an electromagnetic valve, and its configuration is well known, so a detailed explanation will be omitted.

Note that 19 is a surge tank.

FIG. 2 is a flowchart showing the processing performed by the intercooler ECII 20. Step 101 determines whether the difference between the pressure P1 detected by the first pressure sensor 12 and the pressure P2 detected by the second pressure sensor 14, that is, the differential pressure across the ink cooler 9, is less than 100 mm 11 g. If this differential pressure is 10 (hml1g or more), it is determined that the ink cooler 9 is clogged, and step 109 is executed to turn on the warning light 18 and this process is terminated.In step 101, the differential pressure ( Pl-P2) is 100mm1
If it is determined that the temperature is less than 1g, step 102 is executed and the atmospheric temperature To detected by the third temperature sensor 1G is 1g.
It is determined whether the temperature is between 0°C and 50°C. When the atmospheric temperature is below 10<0>C or above 50<0>C, the system ends without working, and steps 103 et seq. are executed in the normal case when the atmospheric temperature is between 10<0>C and 50<0>C.

Step 103 is the difference between the temperature f1 detected by the first temperature sensor 10 and the temperature T2 detected by the second temperature sensor 11;
That is, it is determined whether the temperature difference before and after the intercooler 9 is greater than 10°C. If the temperature difference is less than 10° C., this indicates that the ink cooler 9 is not functioning sufficiently, and step 108 is executed to reduce the boost pressure. For example, if the bypass valve 31 has a supercharging pressure of 4Of)m+
Even if it is set not to open until +l1g, 300mm1! It is controlled to open when it reaches g. In other words, if the temperature difference (TITz) is 10"C or less, it means that the ink cooler 9 is abnormal. Therefore, in step 108, the boost pressure is reduced by 100mmt1g, and at the same time, step 109 is executed to turn on the warning light, and the main Shut down the system.

If the temperature difference (T, -T2) exceeds 10°C, then step 104 is executed, and the temperature difference (T+, T2) is 35°C.
Determine whether the value is greater than or not. As a result, the temperature difference (T,
-'r2) is 10° C. to 35° C., it is determined that the ink cooler 9 is functioning normally, and step 110 is executed and the process ends. That is, in step 110, if the supercharging pressure is deviated from the normal state, the supercharging pressure is returned to the original value and the bypass valve 31 is controlled to open in the normal state.

On the other hand, in step 104, the temperature difference (T, -T2)
is higher than 35° C., the cooling capacity of the ink cooler 9 is sufficient, and the supercharging pressure is increased according to the conditions in the next step 105 and subsequent steps.

First, in step 105, the opening degree of the throttle valve 13 is set to 50.
It is determined whether or not it is larger than °. If this opening degree is 50 degrees or less, it is determined that the engine load is not so large, and there is no need to increase the boost pressure, so the process moves to step 110 and the boost pressure is returned to the normal state. On the other hand, if the opening degree exceeds 50°, the engine load is large and it may be necessary to increase the boost pressure, so the next step 106
, 107, the boost pressure is increased.

In step 106, it is determined whether the M angle Jla of the knock control is smaller than 3 degrees. If this retard amount is 3° or more, it means that knocking is likely to occur, so the boost pressure cannot be increased any further, and step 110 is executed to return the boost pressure to its original value. return. On the other hand, if the retard amount is larger than 3 degrees, step 10
Step 7 is executed to determine whether or not the boost pressure has already been increased by 5 QmHg.If the boost pressure has not been increased yet, step 111 is executed to increase the boost pressure by 50 miHg, and the boost pressure has already been increased by 5QmHg. If the boost pressure has been increased, the boost pressure will not be increased any further and this system will be terminated.

Now, in each of the above steps 108, 110, and 111, the ink cooler ECU 20 does not directly control the boost pressure, but outputs a signal for changing the boost pressure. This signal is input to the boost pressure control ECU 22,
This ECU 22 applies voltage to the electromagnetic valve of the actuator 30 to open and close the bypass valve 31 to control the boost pressure.

Since the apparatus of this embodiment has the above configuration, if the ink cooler 9 becomes clogged or its function deteriorates abnormally,
The driver can detect the abnormality by lighting the warning light 18.
Quick repair processing becomes possible. Furthermore, when the cooling function of the ink cooler 9 deteriorates, the bypass valve 31 is opened in step 108 to lower the supercharging pressure, thereby preventing the occurrence of non-king and protecting the engine. Further, if the function of the ink cooler 9 is sufficient, the engine load is large, and there is no possibility of knocking occurring, the opening of the bypass valve 31 is regulated in step 111, the supercharging pressure is increased, and the engine output Further improve the
As a result, fuel consumption can be reduced.

Effects of the Invention As described above, according to the present invention, when the function of the ink cooler deteriorates, the supercharging pressure can be reduced to prevent the occurrence of knocking, thereby protecting the engine.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, and FIG. 2 is a flow chart showing processing of an ink cooler engine control unit. 1... Engine body, 2... Intake pipe, 4... Turbocharger, 9... Intercooler, 10... First
Temperature sensor, 11... Second temperature sensor, 20... Engine control unit for intercooler (control unit,
). Patent applicant Toyota Motor Corporation Patent application agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Kyosuke Tsuchinakayama Patent attorney Akira Yamaguchi

Claims (1)

[Claims] 1. First and second temperature sensors that detect the temperature before and after the intercooler, which are installed in the intake pipe between the turbocharger compressor and the engine body, respectively, and open and close a passage that bypasses the turbocharger turbine. and a control unit that opens the bypass valve to reduce the supercharging pressure of the turbocharger when the difference between the temperatures detected by the first and second temperature sensors is below a predetermined value. Characteristic turbocharger boost pressure control device.