JPH01177407A - Cooling control method for turbocharger and intercooler - Google Patents

Abstract

PURPOSE:To control always an intake air temperature properly regardless of the change of a driving condition, by enabling operation of a water pump, when an intake air temperature on the downstream side from an intercooler and a load of an internal combustion engine are at respective set values or more. CONSTITUTION:The intake air manifold 1 of an engine main body E is connected to an air cleaner 6 through an intercooler 4 and a turbocharger 5 or the like. And the water jacket 11 of the turbocharger 5 and the intercooler 4 are connected in parallel to the ejection port of a water pump 13 whose water absorption port is connected to a radiator 12. In this occasion, on or off operation of the water pump 13 is controlled by a control means C on the base of respective detected signals from a water temperature sensor SW, an intake air temperature sensor SA and a rotational speed detecting device SN. And the water pump 13 is put on in operation when an intake air temperature on the downstream side from the intercooler 4 and a load of the engine main body E are at respective set values or more.

Description

Detailed Description of the Invention A1 Objective of the Invention (1) Industrial Application Field The present invention relates to a turbocharger connected in a closed circuit between a radiator and a water pump for supplying cooling water. The present invention relates to a cooling control method for a turbocharger and an intercooler for controlling the amount of cooling water supplied to a water jacket and an intercooler.

(2) Prior Art Conventionally, there is a system (Japanese Utility Model Publication No. 31144/1983) in which a water pump is activated when the outside temperature is above a predetermined value to prevent overcooling and overheating of intake air.

(3) Problems to be Solved by the Invention However, in the conventional system described above, when the vehicle is running at high speed, water is efficiently cooled by the radiator, so the cooling efficiency of the water jacket and intercooler is improved. , the intake air temperature may drop too much, putting more load on the engine than necessary.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cooling control method for a turbocharger and an intercooler that can control intake air temperature to an appropriate temperature without being affected by vehicle speed or engine operating conditions. With the goal.

B0 Structure of the Invention (1) Means for Solving Problems According to the method of the present invention, when the intake air temperature downstream of the intercooler is above a predetermined value and the engine load is above a predetermined value, the water Allows the pump to operate.

(2) Effects According to the above method, the operation of the water pump can be controlled under conditions that take into account all factors such as outside temperature fluctuations, supercharging conditions, and vehicle running conditions, making it possible to prevent overcooling and overheating of intake air. becomes.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 1, an intake manifold 1 is connected to the intake boat of each cylinder in the engine body E of a multi-cylinder internal combustion engine, and The manifold 1 is further connected to an air cleaner 6 via an intake pipe 2, a throttle body 3, an intercooler 4, and a turbocharger 5. In addition, an exhaust manifold 7 is connected to the exhaust boat of each cylinder.
This exhaust manifold 7 is connected to a catalytic converter 9 containing a three-way catalyst through an exhaust pipe 8 having a turbocharger 5 interposed in the middle. Furthermore, fuel injection valves 10 for injecting fuel toward the intake ports of each cylinder are attached to a portion of the intake manifold 1 close to each intake port.

The turbocharger 5 is provided with a water jacket 11, and the inlet of the water jacket 11 is connected to the intercooler 4.
The inlet is connected in parallel to the discharge port of a water pump 13 whose suction port is connected to the radiator 12, and the outlets of the water jacket 11 and the intercooler 4 are connected to the radiator 12. The radiator 12 is provided separately from a radiator for cooling water on the side of the engine body.

Next, the configuration of the turbocharger 5 will be described with reference to FIGS. 2, 3, and 4. The turbocharger 5 includes a compressor casing 14, a back plate 15 that closes the back surface of the compressor casing 14, and ,
It includes a bearing casing 17 that supports a main shaft 16 and a turbine casing 18.

A scroll passage 19 is defined between the compressor casing 14 and the back plate 15, and the compressor casing 1
An inlet passage 20 extending in the axial direction is formed in the central portion of 4. Moreover, a compressor wheel 21 is attached to one end of the main shaft 16 in the central portion of the scroll passage 19 and located at the inner end of the inlet passage 20.

The compressor casing 14 and the back plate 15 are fastened together by a plurality of bolts 22, and a bearing casing 17 is connected to the center of the back plate 15.

A pair of bearing holes 23.24 are coaxially drilled in the bearing casing 17 at a distance from each other, and the main shaft 16 and the bearing holes 23, 24 are inserted into these bearing holes 23.24.
Radial bearing metals 25 and 26 are interposed between them, respectively, so that the main shaft 16 is rotatably supported by the bearing casing 17. Further, a collar 27, a thrust bearing metal 28, and a bushing 29 are interposed between the step portion 16a of the main shaft 16 facing the compressor wheel 21 side and the compressor wheel 21 in this order from the step portion 16a side. By screwing and tightening a nut 30 that abuts the outer end of the main shaft 16 to one end of the main shaft 16, the main shaft 16 is supported in the thrust direction and the compressor wheel 21 is attached to the main shaft 16.

A lubricating oil introduction hole 32 connected to a lubricating oil pump (not shown) is provided in the upper part of the bearing casing 17, and a lubricating oil introducing hole 32 is provided in the bearing casing 17 to the radial bearing metal 25, 26 and the thrust bearing metal 28. A lubricating oil passage 33 is bored to guide the supplied lubricating oil.

Further, a lubricating oil outlet 34 is provided in the lower part of the bearing casing 17 for discharging the lubricating oil flowing out from each lubricating part downward. collected in the sump.

The bushing 29 is disposed through a through hole 35 drilled in the center of the blue plate 15, and is disposed through the thrust bearing metal 2.
A seal ring 36 is interposed between the outer surface of the bushing 29 and the inner surface of the through hole 35 in order to prevent lubricating oil flowing out from the bushing 8 from flowing toward the compressor wheel 21 side.

Further, a guide plate 37 is sandwiched between the back plate 15 and the thrust bearing metal 28 and allows the bushing 29 to pass therethrough. Therefore, the lubricating oil flowing out from the thrust bearing metal 28 is scattered radially outward from the bushing 29 and the guide plate 3
It is accepted at 7. Moreover, the lower part of the guide plate 37 is curved to smoothly guide the received lubricating oil to the lubricating oil outlet 34.

The bearing casing 17 is provided with a water jacket 11 around the main shaft 16, and a water supply port 38 for introducing water from the water pump 13 (see FIG. A water outlet 39 is drilled to introduce water to the radiator (see Figure 1).
The closer part is formed in an annular shape surrounding the main shaft 16, and the part corresponding to the upper part of the lubricating oil discharge port 34 is formed in the shape of an annular ring surrounding the main shaft 16.
The water supply port 39 is formed to have a substantially U-shaped cross-sectional shape that opens downward above the water jacket 6, and the water supply port 39 is bored in the bearing casing 17 to communicate with the lower part of the water jacket 11. is bored in the bearing casing 17 to communicate with the upper part of the water jacket 11.

The turbine casing 18 is provided with a scroll passage 41, an inlet passage 42 that communicates with the flow source passage 41 and extends in the tangential direction, and an outlet passage 43 that communicates with the scroll passage 41 and extends in the axial direction.

Bearing casing 17 and turbine casing 18 are coupled to each other with back plate 44 sandwiched therebetween. That is, a plurality of stud bolts 45 are screwed into the turbine casing 18, and the bearing casing 17
The bearing casing 17 and the turbine casing 18 are connected to each other by tightening the ring member 46 that engages with the nut 47 that is screwed onto the stand bolt 45, and the flange portion 44a provided on the outer periphery of the back plate 44 is connected to the bearing casing. 17 and the turbine casing 18.

A fixed vane member 48 is fixed to the back plate 44, and the fixed vane member 48 divides the inside of the scroll passage 41 into an outer circumferential passage 41a and an inflow passage 41b. The fixed vane member 48 has a cylindrical portion 4 that fits coaxially into the outlet passage 43.
8a, a disk portion 48b extending radially outward from the outer surface of the intermediate portion of the cylindrical portion 48a, and a plurality of, for example, four, fixed vanes 49 extending from the outer peripheral end of the disk portion 48b toward the back plate 44 side. A turbine wheel 50 provided at the other end of the main shaft 16 is housed within the fixed vane member 48. The cylindrical portion 48a is fitted into the outlet passage 43 through a seal ring 51 fitted on the outer surface thereof, and the fixed vane 49 is coupled to the back plate 44 by bolts 52.

The fixed vanes 49 are provided on the outer periphery of the turbine member 48 at equally spaced positions in the circumferential direction, and each fixed vane 49 is formed in an arc shape. Also, between each fixed vane 49, a back plate 4 is arranged parallel to the axis of the main shaft 16.
Movable vanes 54 having one end fixed to a rotation shaft 53 rotatably connected to the fixed vanes 4 are arranged, and the flow area of the gap between the fixed vanes 49 is adjusted by these movable vanes 54.

Each movable vane 54 is formed in an arc shape with the same curvature as the fixed vane 49, and is rotatable between a fully closed position shown by a solid line in FIG. 3 and a fully open position shown by a chain line. Moreover, each rotation shaft 53 is connected to an actuator (
(not shown), and each movable vane 54 is driven to open and close in synchronization with the operation of the actuator.

A shield plate 56 extending to the back of the turbine foil 50 is sandwiched between the back plate 44 and the bearing casing 17, and the heat of the exhaust gas flowing through the inflow path 41b is directly transferred to the inside of the bearing casing 17 by this shield plate 56. This will be prevented as much as possible. In addition, exhaust gas flows into the bearing casing 1.
In order to prevent the main shaft 16 from leaking into the turbine casing 18, the main shaft 16 is located at a portion corresponding to the through hole 57 provided in the bearing casing 17 to allow the main shaft 16 to protrude into the turbine casing 18.
A plurality of annular grooves 58 are provided which function as labyrinth grooves.

In such a turbocharger 5, exhaust gas discharged from the engine body E flows into the outer circumferential passage 41a from the inlet passage 42, and the flow area of the gap between the movable vane 54 and the fixed vane 49 corresponds to the amount of rotation of the movable vane 54. The exhaust gas flows into the inlet passage 41b at a flow rate corresponding to
is rotated and discharged from the outlet passage 43. According to the rotation of this turbine wheel 50, the compressor wheel 21
rotates, and the air led from the air cleaner 6 to the inlet passage 20 is supplied toward the intercooler 4 via the scroll passage 19 while being compressed by the compressor wheel 21. The temperature increase in the bearing casing 17 due to the temperature increase during air compression is prevented as much as possible by supplying cooling water to the water jacket 11, and the increase in intake air temperature is also prevented by supplying cooling water to the intercooler 4.

Referring again to FIG. 1, the on/off operation of the water pump 13 is controlled by control means C consisting of a computer. The control means C includes a water temperature sensor S that detects a water temperature T1 of a water jacket (not shown) provided in the engine body E. An intake air temperature sensor SA that detects the intake air temperature T^ on the downstream side of the intercooler 4, and rotation speed detectors S and l that detect the engine rotation speed N are connected. The control means C also controls the operation of each fuel injection valve 10 in order to control the amount of fuel supplied according to the operating state of the engine,
The control means C calculates the amount of fuel to be injected according to the operating state of the engine, and controls the operation of each fuel injection valve lO based on the calculation result, and the actual fuel injection amount T. u7 can be detected inside the control means C. As a result, the control means C controls the water temperature Tw, the intake air temperature TA%, the engine speed NL, and the actual fuel injection amount T1. tl? The on/off operation of the water pump 13 is controlled based on this.

Here, the amount of fuel injection performed by the control means C is T.

To explain the calculation of the fuel injection amount T. U is calculated based on the following equation (1).

Toll? "Tt X K l+ Kg"・(1
) In this equation (1), T1 is the basic injection amount of the fuel injection valve 10, and is set so that the air-fuel ratio is 14.7 according to the engine speed N and the absolute pressure in the intake pipe. To,
are various correction coefficients determined by, for example, intake air temperature TA, water temperature Tw, throttle opening, etc., and Kt is a correction constant for increasing the amount during acceleration, for example.

In addition, as shown in FIG. 5, the water temperature T-
The first set water temperature T IlI CI and the second set water temperature T
The engine speed NE is divided into i-1 to 3 by wIcz, and the engine speed NE is divided into j-1 to 3 by the first set engine speed NE and the second set engine speed N□. A map forming a street address is set, and ij
Each address determined by the set fuel injection amount TOII? IC1j
are set respectively.

Next, the control procedure by the control means C will be explained with reference to FIG. 6. In the first step S1, each data, namely, the water temperature Tw, the intake air temperature T^, the engine speed N, and the actual fuel injection amount T' ot+r is read, and in the next second step S2, the water temperature Tw is set to the set water temperature T. It is determined whether it is higher than ICN. Set water temperature T□. is determined with hysteresis; for example, too@C/
It is set to 98@C. In the second step S2, the water temperature T1.
When it is determined that l is higher than the set water temperature T%llICM, the process advances to the third step S3.
3 is the engine rotation speed N, which is the set rotation speed N equivalent to idling.
It is determined whether or not it is less than 1°7. In this third step S3, N* <N. ? If so, the process proceeds to the fourth step S4, where the operation of the water pump 13 is stopped, and Na≧N.
! If it is LOP, the process advances to the twenty-third step 323.

When it is determined in the second step S2 that T, ≦TI+llCM, it is determined in a fifth step S5 whether the engine rotational speed N is less than the set rotational speed N0. This fifth step S5 is for determining whether or not cranking of the engine has started, and the set rotational speed NEA is set to, for example, about 400 rpm. When it is determined in this fifth step S5 that N t a > N t, the process proceeds to a fourth step S4, and NEA≦N t.
If it is determined that , then the process advances to the sixth step S6.

In the sixth step S6, it is determined whether a predetermined period of time has elapsed after starting the engine, for example, whether a predetermined number of TDC pulses have been generated after the engine has started, and if the predetermined period of time has not elapsed, the process proceeds to a fourth step S4 If the predetermined time has elapsed, the process advances to the seventh step S7. In the seventh step S7, the intake air temperature TA is the first set intake air temperature T□. It is determined whether or not the value is less than or not. This first set intake air temperature Ta
Ic + is set with hysteresis, for example 15"C/13"C. TA<T
If AI is 1, proceed to the eighth step S8, and T
, ≧T Ar c +, the ninth step S9
Proceed to.

In the eighth step S8, the actual fuel injection amount is equal to the set fuel injection amount T. It is determined whether the value exceeds oy+co. This set fuel injection amount T. U? IC6 is for determining whether or not the engine is in a high-load operating state. When TOLI7>T'out+co, that is, when the engine is in a high-load operating state, the process proceeds to the 23rd step S23, and T out? When ≦T'ouyrco, that is, when the engine is in a medium or low load operating state, the process advances to the fourth step S4.

In the ninth step S9, it is determined whether the intake air temperature TA can exceed the second set intake air temperature TAICt.

This second set intake air temperature T A I Ct is set with hysteresis, for example, 90@C/8
8@C. In this ninth step S9, Ta>Thrc
When it is determined that t, the tenth step S10
Proceed to TA≦TAIC! If it is determined that this is the case, the process proceeds to the eleventh step 311.

In the 10th step SIO, the fuel injection amount T. Ua is the set fuel injection amount T. It is determined whether it is less than tlflc4. This set fuel injection amount T. tlTIc4 is for determining whether the engine is in a medium load state, and when Tour>Touy+c4, that is, when the engine is in a medium or high load operating state, the process proceeds to the 23rd step S23, and 'ro, When Jt≦TOUTIC4, that is, when the engine is in a low load operating state, the process advances to a fourth step S4.

The steps from the 11th step Sll to the 20th step S20 are procedures for determining the address of the map shown in FIG.
It is determined whether w r c is less than 1, T,
When 1<Tw□c1, i=1 is set in the twelfth step S12, and when T, ≧TMICI, the water temperature T8 is set to the second set water temperature 'rw in the thirteenth step 513.
It is determined whether it is less than +ez. TI, <T
When w+cz, i-2 is determined in the 14th step S14.
Therefore, Tw≧T W I e! , the first
In step S15, i=3.

Here, the first and second set water temperatures T w lc I+ T
w + c z is determined with hysteresis, and the first set water temperature T W I CI is, for example, 2
0”C/113°C, and the second set water temperature T w r
c t is, for example, 50°C/4B''C.

- After the processing of steps S12 and 14.15 are completed, the process proceeds to the 16th step S16, and in this 16th step S16, the engine rotation speed NA is equal to the first set rotation speed N! It is determined whether it is less than l C1. When N t < N e + c l, the first
In the seventh step 317, j=1, and when N≧NtICI, it is determined in the 18th step 31B whether the engine rotational speed N is less than the second set rotational speed NEIC2, and Nt<N. When t t c t, j=2 is set in the 19th step S19, and N, ≧N,
1C! If so, j=3 is set in the 20th step S20.

Here, the first and second set rotation speeds N t Ic 1+
For example, N t +0 is 3500 rpm, 6000 rpm
m, respectively.

By determining i and j in this way, the address in the map shown in FIG. 5 is determined, so the next 21st step 3
21 is the set fuel injection amount T of the corresponding address. □Ic1j is read. Next, in the 22nd step 322, the actual fuel injection amount T is determined. U? is the set fuel injection ITOUTIc! read from the map. It is determined whether or not it exceeds J. Here To. ,>Toat+cmj, then
Proceeding to the 23rd step S23, Toot≦Tout+c
! i, the process proceeds to the fourth step S4. In the twenty-third step S23, the battery voltage V is set to the set voltage VII.
It is determined whether Vs>V□. If so, the operation of the water pump 13 is started in the 24th step S24, and Vl≦V□. If so, the process advances to the fourth step S4.

Moreover, the set fuel injection amount T'ou↑11 at each address in the map shown in FIG. 5 is set as follows for the low-load operating state and the high-load operating state of the engine, respectively.

In other words, when the engine is operating at low load, addresses 1j-32,
The set fuel injection amount Toov+ctj at 23 and 33 is the actual fuel injection 11T to enable the operation of the water pump 13.
address 1j = 31.22° 32.13, 23.3 when the engine is operating under high load.
The set fuel injection amount Tout+ctj in 3 is the actual fuel injection amount T to enable the operation of the water pump 13. It is set to be less than □.

Next, to explain the operation of this embodiment, the operation of the water pump 13 is stopped when the engine is started, and when the intake air temperature TA is low after the engine starts and is less than the first set intake air temperature TAIc1, the engine starts. The operation of the water pump 13 is turned off during low and medium load operating states, and the water pump 13 is turned on during high load operating states. In addition, the intake air temperature TA is the second set intake air temperature TAI. In a high intake air temperature state exceeding , the operation of the water pump 13 is turned off when the engine is in a low load operation state, and the operation of the water pump 13 is turned on when the engine is in a medium or high load operation state. Become.

Also, the intake air temperature TA is the second set intake air temperature T, 1c! When the intake air temperature is lower than the first set intake air temperature T A I C1 or higher, the set fuel injection amount T'ouytc! is set based on a map determined by the water temperature T,1 and the engine speed N.
j and the actual fuel injection amount T. Compare □, T,. 7>TO
Since the water pump 13 is enabled to operate only when the engine is tlTIC4j, it is possible to perform control immediately responsive to the operating state of the engine. This prevents the intake air from being cooled more than necessary during high-load operation when the engine is cold, and prevents the intake air temperature TA from rising too much during low-load operation immediately after high-load operation. Therefore, it is possible to efficiently prevent overcooling and overheating of the intake air and overheating of the turbocharger 5 by turning on the water pump 13 to the necessary minimum, and it is also possible to prevent wasteful power consumption.

Furthermore, since the on/off operation of the water pump 13 is controlled according to the intake air temperature Ta, the intake air temperature TA can be appropriately controlled while taking into consideration all outside temperature fluctuations, supercharging status, vehicle running status, etc. Supercooling of the intake air does not occur during high-speed driving, and supercooling and overheating of the intake air can be prevented.

Note that the water pump 13 will stop operating unless the intake air temperature Ta is high and the engine is running under high load, but at that time the water remaining in the water jacket 11 and intercooler 4 will provide sufficient cooling. will be carried out.

C0 Effects of the Invention As described above, according to the method of the present invention, the water pump can be operated when the intake air temperature downstream of the intercooler is above a predetermined value and the engine load is above a predetermined value. Therefore, the operation of the water pump can be controlled so that the intake air temperature is at an appropriate value regardless of the driving condition of the vehicle or changes in outside temperature, etc., and supercooling and overheating of the intake air can be prevented.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall schematic diagram showing the intake system and exhaust system of an internal combustion engine, FIG. 2 is an enlarged vertical cross-sectional view of a turbocharger, and FIG. ■-
■ Line sectional view, Figure 4 is a TV-IV line sectional view in Figure 2, Figure 5 is a diagram showing a map set by the control means, and Figure 6 is a flowchart showing the processing procedure by the control means. . 4... Intercooler, 5... Charbocharger,
11...Water jacket, 12...Radiator, 13
...Water pump, E...Engine body Fig. 3 Fig. 4 Fig. 5

Claims (2)

[Claims] (1) A turbocharger and intercooler for controlling the amount of cooling water supplied to the turbocharger's water jacket and intercooler, which are connected in a closed circuit between the radiator and a water pump for supplying cooling water. A cooling control method for a turbocharger and an intercooler, characterized in that the water pump can be operated when the intake air temperature downstream of the intercooler is above a predetermined value and the engine load is above a predetermined value. Cooling control method. (2) A cooling control method for a turbocharger and an intercooler according to claim (1), wherein the engine load is detected based on the fuel injection amount.