JPH01240735A - Supercharged pressure control method in internal combustion engine - Google Patents

Abstract

PURPOSE:To improve acceleration characteristic by restraining the raising speed of supercharged pressure when a transmission gear stays on a low speed position. CONSTITUTION:A turbocharger 4 is provided on the way between an intake pipe 2 and an exhaust pipe 3. The movable vanes of the turbocharger 4 are put in action by an actuator 17. It is judged by the detected value of an engine r.p.m. sensor 14 and a vehicle speed sensor 24 that the transmission gear stays on the first speed position and at this time, the duty ratio of a duty controlled electro-magnetic control valve 18 for introducing the supercharged pressure is made small. Thereby, the rapid raise up of the supercharged pressure and overboost can be prevented and acceleration characteristic can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling boost pressure of an internal combustion engine, and more particularly to a control method for appropriately controlling boost pressure when a transmission is in a low gear position. .

(Prior art) Conventional method (as a method of controlling the boost pressure of a dual-purpose internal combustion engine, open-loop control is performed when the boost pressure is in a transient state such as when it increases rapidly, and feedback control is performed when the boost pressure is in a steady state). For example, the present applicant has already proposed a method to do this (Japanese Patent Application No. 61-2).
No. 75783), this prevents control hunting caused by a delay in response of the control system when feedback control is performed in a transient state, and performs circular supercharging pressure control.

(Problems to be Solved by the Invention) However, the control method proposed above obtains good acceleration characteristics when the transmission is in the low gear position, and also ensures the durability of the engine and other components. There was room.

In other words, when the transmission is in a low gear position such as the 1st gear position, the rate at which the engine speed rises is faster than when it is in a high gear position, so the rate at which the boost pressure rises tends to be faster. This tendency is particularly high when starting suddenly. On the other hand, the control method described in "-" is configured to uniformly perform supercharging pressure control in a transient state regardless of the gear position of the transmission, and the control system is inherently accompanied by a delay in response. Therefore, in a sudden transient state when the transmission is in the low gear position 1α, the rising speed of the boost pressure exceeds the control speed and the boost pressure suddenly decreases. Due to the rapid rise in output, wheel spin and overboost occur in the drive wheels of the vehicle, making it impossible to obtain good acceleration characteristics of the engine.

In addition, in the control method described above, the target boost pressure for feedback control in a steady state is set uniformly regardless of the gear position of the transmission, so the pressure applied to the gear in a steady state is applied to the low gear position where the reduction ratio is large. Torque increases,
Coupled with the above-mentioned occurrence of overboost, this adversely affects the durability of the engine and other components.

In addition, in order to avoid such problems, a control method is known in which the supercharging pressure is reduced when the transmission is in a low gear position (for example, Japanese Patent Laid-Open No. 62-276
223 Publication), this control method is applied to a so-called wastegate type supercharger that bypasses the turbine and releases part of the exhaust gas, so it cannot be applied to other types,
For example, it cannot be applied to a type of supercharger that controls boost pressure by controlling the opening degree of a movable vane disposed on the turbine inlet side.

The present invention has been made in order to solve the problems of the prior art described above, and reduces the boost pressure when the transmission is in a low gear position without causing a sudden increase in boost pressure or overboosting. An eleventh object of the present invention is to provide a method for controlling the boost pressure of an internal combustion engine, thereby improving the acceleration characteristics of the engine and the durability of the engine.

(Means for Solving the Problems) In order to achieve the above object, the present invention detects an increase in supercharging pressure by a supercharger of an internal combustion engine, and when the transmission is in a low gear position, This is designed to suppress the rate of increase in the 0;I feed pressure in a transient state more than in other gear positions.

The present invention also provides a method for controlling the boost pressure of an internal combustion engine that controls the opening degree of a movable vane disposed on the turbine side of a supercharger. The basic supercharging pressure control claw or the supercharging pressure feedback control is designed to lower the standard supercharging pressure by 1'' compared to when the gear is in the gear position.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram of a control device for an internal combustion engine equipped with a turbocharger to which the control method of the present invention is applied.

The symbol l in the figure indicates, for example, a 6-cylinder internal combustion engine,
The intake pipe 2 is on the upstream side of the engine l, and the exhaust pipe 3 is on the downstream side.
are connected, and a turbocharger 4 is interposed between the intake pipe 2 and the exhaust gas ff3.

The intake pipe 2 is provided with an air cleaner 5, an intercooler 6, and a throttle valve 7 in this order from the upstream side.

An atmospheric pressure (P^) sensor 8 is installed between the air cleaner 5 and the turbocharger 4 at the open end of the intake pipe 2 on the atmosphere side, and detects the intake pressure in the intake pipe section between them, that is, the atmospheric pressure. , the detection signal is supplied to an electronic control unit (hereinafter referred to as rECUJ) 9.

Throttle valve 7 has throttle valve power ((1? TII
) A sensor 10 is connected to convert the valve opening of the throttle valve 7 into an electrical signal and send it to the ECU 9.

On the other hand, the intake pipe absolute pressure (P
IIATC) sensor 11 is provided, and this 1)8
The absolute pressure signal converted into an electrical signal by the Tc sensor 11 is sent to the IE CU 9.

In this embodiment, the PB^C sensor 11 performs feedback control in the substantially fully open f1'1 region of the throttle valve 7 in the boost pressure control by the turbocharger 4, as will be described later. The magnitude of the boost pressure in the downstream intake path can be detected as an intake pressure value in the intake path portion obtained by the P5Atc sensor 11 provided downstream of the throttle valve 7. Therefore, E
CU9 has PBATC under the throttle valve fully open condition.
Information regarding the boost pressure is also supplied from the sensor 11.

In addition, downstream of the P BATC sensor 11, there is an intake air temperature (T^
) A sensor 12 is attached, which detects the intake air temperature 1゛^ and outputs a corresponding electrical signal to be supplied to the ECU 9.

A fuel injection valve 13 is provided in the intake pipe 2 between the engine l and the throttle valve 7. This fuel injection valve 13 is provided for each cylinder on the first flow side of the intake valve of the intake pipe 2 (
(only two are shown), each injection valve 13 is connected to a fuel pump (not shown) and electrically connected to the ECU 9, and the valve opening time of fuel injection, that is, the amount of fuel supplied, is controlled by a signal from the ECU 9. be done.

The engine rotation speed (Ne) sensor 14 is attached around the camshaft or crankshaft (not shown) of the engine l and is connected to the ECU 9, and generates a TDC signal, that is, a predetermined signal every 180 rotations of the crankshaft of the engine l. One pulse is output at the crank angle position and this pulse is supplied to the ECU 9.

Further, a three-way catalyst 15 is arranged downstream of the turbocharger 4 in the exhaust pipe 3 .

The turbocharger 4 is of a variable capacity type, and its operation control system includes an actuator 17 having a drive rod 16 linked to a movable vane 64 (FIG. 3), which will be described later, and a duty-controlled supercharging pressure. It has an introduction electromagnetic control valve 18 (hereinafter simply referred to as "control valve") and a regulator 19.

FIG. 2 shows an overall schematic diagram of the turbocharger 4. That is, the turbocharger 4 includes a compressor casing 41 that forms the scroll of the compressor portion, a back plate 42 that closes the back surface of the compressor casing 41, and a main shaft 43 of the turbocharger 4 that pivotally supports the bearing and lubricates and cools the bearing. It has a bearing casing 44 that incorporates a structure in which water circulates, and a turbine casing 45 that forms a scroll of the turbine portion.

Inside the compressor casing 41, a scroll passage 46 and an axial passage 47 to which the intake pipe 2 is connected are formed, the former 4G serving as an intake 1], and the latter 4
7 constitutes an intake port 1-1.

In one part of the intake manifold, a compressor wheel 48 is attached to one end of the main shaft 43.

The main shaft 43 is supported in the bearing hole 49.50 of the bearing casing 44 by a radial bearing metal 51 and a thrust bearing metal 52.

Further, the bearing casing 44 is formed with a lubricating oil introduction hole 53, a lubricating oil passage 54, a lubricating oil discharge 1] 55, and a water jacket 56.

Inside the turbine casing 45, a scroll passage 5 is provided.
7 and its population U old that opens in the tangential direction” 57a
, an outlet 1'' passage 58 extending in the direction of the axis, and an outlet opening 58a thereof are rounded, and the inlet opening 57a and the outlet opening 58a are connected to the exhaust pipe 3, respectively.

The outer circumference of the fixed vane member 60 fixed to the back plate 59 so as to be disposed in the center of the scroll passage 57 includes:
As shown in FIG. 3, a plurality of fixed vanes 62, for example, four fixed vanes 62, are formed so as to concentrically surround a turbine wheel 61 provided at the bottom end of the main shaft 43. These fixed vanes 62 each have a partial arc shape, and are provided with the same width and at equal intervals along the circumferential direction. Til movable vanes 64 fixed to the free ends of rotary bins (5; 3) rotatably mounted on the back plate 51) are arranged between the fixed vanes 62, respectively.

These moving vanes 64 have an arc shape with the same curvature as the circumferential vane 62, and are located at approximately the same circumference -L, and have a minimum opening position shown by a solid line in FIG. 3 and a chain line shown by a chain line. It can be rotated between the fully open position and the fully open position.

The gaps between the fixed vanes 62 are opened and closed by the movable vanes 6/I being rotated in synchronization, and the circulation area of each gap is the amount of rotation, that is, ++(
It is adjusted according to the inclination angle of the moving vane 64.

The synchronized rotational drive of each movable vane 64 is achieved by a rotational pin 63 supporting each movable vane 64, a link mechanism 65 (FIG. 2) connected to the rotational pin 63, and a linkage mechanism 65 connected to the rotational pin 63. This is done by its actuator I7 via the previously described drive rod 16 (FIG. 1). Drive rod 16
The link mechanism 65 is configured such that when the drive rod 16 is operated in the extending direction (leftward in FIG. 1), the opening degree of each movable vane 64 increases and the flow area of each gap increases. , and when operated in the contraction direction (rightward in Figure 1), the opening degree is reduced and the flow area of each gap is reduced, and by controlling the opening degree, the turbocharger 4 capacity is adjusted.

That is, the variable capacity turbocharger 4 having the above configuration
In this case, exhaust gas discharged from the main body of the engine 1 flows into the scroll passage 57 from the input 11 passage 57a on the turbine side, and the movable vane 64 is rotated according to the amount of rotation of the movable vane 64.
Exhaust gas flows into the turbine wheel 61 side at a flow rate according to the flow area of the gap between the fixed vanes 62, rotates the turbine wheel 61, and is discharged from the first passage 58. The flow velocity of the exhaust gas that drives the turbine wheel 61 is I
- As a result, if the flow area of the gap between each movable vane 64 and the fixed vane 62 is small and the flow velocity is high, the turbine wheel 61. That is, the rotation speed of the main shaft 43 becomes faster, and each movable vane 64 and fixed vane 611+1
If the flow area of the gap 1 is large and the flow velocity is low, the turbine wheel 61. That is, the rotational speed of the main 11+11143 becomes slower. Since the compressor wheel 48 rotates in accordance with the rotation of the turbine wheel 61, the air guided from the air cleaner 5 to the axial passage 47 flows through the compressor wheel 4.
8, the intake air is compressed according to its rotational speed and is supplied to the intercooler 6 via the scroll passage 4G, thereby pressurizing the intake air.

Thus, when the movable vane 64 is located at the outermost radial position of the turbine casing 57 and the air gap circulation area between it and the fixed vane 62 is minimized, that is, when the opening degree is minimized, the supercharging pressure is maximized, and the movable vane 64 to turbine casing 5
7, the fixed vane 62 is located at the innermost position in the radial direction.
The supercharging pressure becomes the minimum when the air gap circulation area between the movable vane 64 is maximized, that is, the opening is maximized, and a high supercharging pressure can be easily obtained by adjusting the opening of the movable vane 64.
In the range between the minimum and maximum l-intelligibility, the supercharging pressure can be changed in a wide range according to the opening degree.

1. As shown in FIG. 1, the actuator 17 that rotationally drives the movable vane 64 of the turbocharger 4 for supercharging pressure control is a first actuator defined by a diaphragm 17a.
It has a pressure chamber +7b and a second pressure chamber 17c, and the drive rod 16 described above passes through the housing on the second pressure chamber 17c side and is connected to the diaphragm 17a. A spring inserted into the second pressure chamber 17b! 7d, the diaphragm l7a is moved (=1 force) in the direction in which the drive rod 16 is contracted, that is, in the direction in which the opening degree is decreased by the movable vane 64.

An intake passage between the air cleaner 5 and the turbocharger 4 is connected to the first pressure chamber 17a via a throttle 22, and an intake passage between the turbocharger 4 and the intercooler 6 is connected to the regulator 19, the throttle 23, and the control valve 18. connected via.

Is the control valve 18 a normally closed on-off two-position operating type? The solenoid 18a and the solenoid l8a
The valve body 18b is opened by excitation of the valve body 18b. When the valve body 18b of the solenoid 1811 (=J force is opened), the turbocharger 4 and intercooler 6
The boost pressure in the intake passage between the
It is introduced into the pressure chamber 17b.

In this case, the diaphragm 1771 is deflected to extend the drive rod 16, and the 14-drive vane 64 of the turbocharger 4 is connected to the drive rod 16 and the link mechanism 65.
is rotated inward, that is, in a direction where the opening degree becomes larger. When the valve body 18b is closed, the introduction of supercharging pressure is cut off, and contrary to the above, the movable vane 64 is driven in a direction in which its opening degree becomes smaller.

Therefore, the valve body 18 in one cycle of turning on and off the solenoid 18a, that is, opening and opening the valve bodies 18 and b.
b, that is, the valve closing duty ratio Dvc (hereinafter simply referred to as "duty ratio"), this is the 100% state @ (when the movable vane 64 is at the above-mentioned minimum opening position and the maximum excess The magnitude of the boost pressure is controlled according to the duty ratio Dvc based on the state of the boost pressure.

The solenoid 18a of the control valve 18 is 1':
The duty ratio 1)vc is controlled by a signal from the ECU f).

Furthermore, ECU 9 has IIF and speed (V
) A sensor 24 is connected and its detection signal is supplied.

1': CLJ O includes an input circuit 9a and a central processing circuit that have functions such as shaping human input signal waveforms from various sensors, correcting voltage levels to predetermined levels, and converting analog signal values into digital signals. (hereinafter referred to as "C")U" 9b, C1"'tJ9b, a storage means 9C1 for storing various calculation programs and calculation results, etc., and an output for supplying drive signals to the fuel injection valve 13 and control valve 18. It is composed of a circuit 9d and the like.

CI) (J9b determines the operating state of the engine 1 based on the input signals from the various sensors described above, and optimizes engine characteristics such as fuel consumption characteristics and acceleration characteristics according to the determined operating state. As shown in FIG.
The fuel is supplied to the fuel injection valve 13 via.

In calculating the fuel injection time, the basic fuel injection time, that is, the basic valve opening time of the injection valve 13 ゛1゛1 is 1)
1) Absolute pressure in the intake pipe based on the detection outputs of the TC sensor 11 and NO sensor 14 1) B^ and engine speed Ne
It is calculated from the '1'i map (not shown) stored in the storage means 9C described above.

In addition, CI) U9b controls the open loop control area of boost pressure control according to the engine operating state according to the control program described below based on human input signals from various sensors.
In addition to setting feedback control areas, etc., and determining whether or not the area is within those areas, the determined control t3
An output circuit calculates the opening degree of the movable vane 64, that is, the duty ratio Dva of the control valve 18 so that the optimum boost pressure can be obtained in one region, and outputs a drive signal that operates the control valve 18 according to the calculated value. 9d, the actuator 17 is connected to the control valve 18 and also to the turbocharger 4.
to drive.

FIG. 4 shows a flowchart of a program for controlling the duty ratio I)vc of the control valve 18, that is, the boost pressure.

First, in step 1101, EC; 1 stored in U9 is
) Read out the reference value 1) van of the duty ratio Dvc from the 7M map in V according to the throttle valve opening OT11 and the engine speed Ne. The 51st part 1 is this Dv
An example of the c+1 map is shown, and the throttle valve opening OTl+
is in 16 steps from 0 + 1VI to Or++vx6 within a predetermined range, and the engine speed Ne is Nvl- within a predetermined range.
There are 20 levels of Nv2o, and at points other than the grid points of the map, the base Qli value 1)v is determined by interpolation calculation.
aM is required. With such a map, base 7il
By setting the J value 1) v a n, the control valve 1
The duty ratio Dvc of 8 can be controlled in more detail according to the operating state of the engine l.

Next, it is determined whether the gear position of the transmission crystal (hereinafter simply referred to as "gear position J") is at the first speed (1st) position (
Step 402). This determination is performed, for example, according to the subroutine shown in FIG.

That is, in step 6, it is first determined whether the speed V at 11F is smaller than the predetermined speed VL, which is normally fH>at the first speed position.
01), when V≧Vt is satisfied, it is determined that the vehicle is not in the first speed position (step 602). On the other hand, in step 601, it is determined whether or not the vehicle speed V is smaller than a predetermined 11rtVp corresponding to the engine rotational speed Ne (when VL is established, step 603), and when V≧VF is established, step 602 is determined. While executing
When V(VF holds true), it is determined that the vehicle is in the first speed position (step 604).

FIG. 7 shows a table for determining the predetermined value VF. That is, when the gear position is at the first speed position, the ratio between the engine speed Ne and the vehicle speed V is in a constant relationship, so the base rIIl value NFI~NF9 of the engine speed No is adjusted to match this relationship. and base Y111 value V of vehicle speed V
FI to Vpe are set in advance as a table, and it is determined that the vehicle is in the first speed position when the vehicle speed V is smaller than a reference value VF corresponding to the actual engine speed Ne. With this configuration, it is possible to determine whether or not the gear position is in the first gear position without using a gear position sensor, etc., not only when the transmission is a manual transmission, but also when the transmission is an automatic transmission. It can be done easily.

Returning to FIG. 4, the answer to step 402 is 1'j constant (Y
es), that is, when the gear position is at the 1st speed position, +
i: Duty ratio Dv obtained in step 401 of j
Predetermined from the reference value DvaM of a! ! After subtracting I'IDF and resetting the reference value DV13N (step 40
3) If negative (No), that is, the gear position is at a position other than the first speed, the process directly proceeds to step 404. In this way, the reference value Dvan of the duty ratio Dva is set to a smaller value by the predetermined value DF when the gear position is at the first speed position than when the gear position is at a position other than the first speed. As a result, when the gear position is in the 1st speed position, the boost pressure is suppressed as a whole, and therefore it is possible to prevent a sudden increase in the boost pressure or overboost.
By controlling the supercharging pressure to a larger value when the engine is in a position other than the first speed (solid line in Figure 19), desired acceleration characteristics can be ensured (broken line in Figure 19).

In step 404, E(?: KV stored in U9
From the T^ map, read out the intake temperature correction coefficient KVT^ according to the engine speed No. and the intake temperature ゛I゛^.

FIG. 8 shows an example of this KVT^ map, where the engine speed Ne varies from Nv-+ to Nv, similar to the above-mentioned Dv++
20 stages as V2O, intake temperature 1" A is I" AVI
~'r There are 8 stages as AV8, and with this map, the intake temperature correction coefficient Kvt^
is set more appropriately.

Next, change the amount of change (hereinafter simply referred to as "amount of change") ΔPa^ in the intake pipe absolute pressure P BATC to the current value 1) r3^
It is calculated by the difference between TCn and the value 1)sAtcn-3 three times before (step 405). This amount of change ΔPn^ is
As will be described later, this is applied to set various constants for calculating the duty ratio Dva, and thereby the increasing gradient of the supercharging pressure is controlled to a desired value.

Next, in step 406, it is determined whether the boost pressure is in a state where oven loop control should be performed. This determination is made according to the subroutine shown in FIG.

First, in step 901, it is determined whether or not the throttle valve opening degree O group is larger than a predetermined opening degree OFB indicating a nearly fully open state.
If ≦OFB is established and the throttle valve 7 is not in an almost fully open state, it is determined that oven loop control should be performed and the process proceeds to step 916 to be described later. In other words, feedback control is performed when the throttle valve 7 is almost in a fully open state. Executed only on

If the answer to step 901 is 17 (Yes), that is, the throttle valve is almost fully open, it is determined whether feedback (F/B) control was performed in the previous loop (step 902), and the answer is 1. Set ° (Y
At step 903), it is determined that feedback control should be continued, and the program is terminated.

If the answer to step 902 is negative (No), that is, oven loop control is being performed in the 011th cycle, it is determined whether the gear position is in the first gear position (step 904), or in a position other than the first gear position. EC
From the ΔI'BASD table stored in U9, a first subtraction value ΔPnASn for positions other than the first speed is determined according to the amount of change ΔPi^ (step 005), and the process proceeds to step 907, which will be described later. The 10191st is this Δl'1lA
An example of the sD table is shown, and the change n(Δ1)II^ to two reference values PIIAI and ΔI)II^2(〉
ΔPB^1) is set, and the larger the ΔPB^ value, that is, the greater the rising gradient of the boost pressure, the first subtraction value ΔPB
As A8D becomes larger, to PB^1, ΔP
B^1 or more and less than ΔPa^2 and ΔI's^2 or more, respectively, ΔP BASD3 to Δ1) BAsl) 1
It has been set.

nil Kisuf Tsubu 904 answer 1 (Yes), l
! 11 When the gear position is in the 1st gear position, it's time to move.
f'l'l :! The first subtraction value ΔI'BASD is the first subtraction value ΔI'BASD.
Speed position 1 [Set the predetermined value Δl'nAsnF of υ11 in step 90G], step 907 (go forward).

The predetermined value ΔP BASIIF is determined in step 90 of 011.
Δr'BAsD for positions other than the ■th speed found in 5
The value 1) is also set to a large value.

Next, in step 907, the intake pipe absolute pressure P RA
TC is converted to the target value P BATRG and the first subtraction value obtained in step 905 or 906 of step 011.
Asn, it is determined whether or not the difference is greater than the difference (PoArRa-ΔP8^5O) (hereinafter referred to as "minimum opening control release pressure").

The target value PBATRG of the intake pipe absolute pressure is set according to the engine speed No., the intake air temperature T^, and the gear position in the I11 control program shown in FIG. 4, as will be described later.

If the answer to step 907 is negative (No), that is, the intake pipe absolute pressure P BATC is equal to the minimum opening control release pressure (1' BA
TRO−ΔPnAsn) or less, both the proportional control term DVP and the integral control term Dvi, which will be described later and are applied to the feedback 111 control, are set to 0.0 in step 9.
08.009), then the duty ratio 1) va is 100
%, that is, the movable vane 64 is set to the minimum opening degree (step 910). That is, PnAtc≦(P I
When IATRO-ΔPnAsn) is established, the minimum opening degree control of the movable vane 64 is executed (FF! It is possible to increase the responsiveness of the boost pressure control by controlling the boost pressure to the maximum and increasing the boost pressure to near the desired pressure value quickly.

Next, the t and FBDLY timers for feedback control delay are reset (step 011), and the process proceeds to step 418 in FIG. 4, where a drive signal based on the duty ratio Dva is output to the control valve 18 and the control program shown in FIG. 4 is executed. end.

Returning to the subroutine of FIG. 9, the answer to step 007 is 6 constant (Yes), that is, the absolute pressure in the intake pipe Pal is the minimum opening control release pressure (PBﾾｾｼRG−ΔPRAs11)
When the gear is rotated, it is determined whether or not the gear position is in the first gear position (Step 012), and if it is in a position other than the first gear, the ΔI) BAFB stored in the ECU 9 is determined.
From the table, find the second subtraction value ΔPIIAPI+ for positions other than 1st speed according to the change claw Δ1)II^ (
Step 913), the process proceeds to step 915, which will be described later.

FIG. 11 shows an example of this ΔP IIAP11 table, and in exactly the same way as FIG. 10, the base Qli value Δ1) mouth^1. ΔI'n^2 is set, Δ
])I(less than ^1, ΔPB^1 or more but less than ΔPII^2, and 8P n^2 or more, respectively, ΔI'1lAF
B3~ΔPIIAPR1(ΔI'1lAFB3<Δl'
1lAFB2<ΔI'1lAFI]1) is set.

When the sumo step 912 is 17 constant (Yes), that is, the gear position is at the first speed position, the second subtraction value Δ1) BAFB is set to the predetermined value ΔPBAFB for the first speed position.
If it is set to F (step 014), the process proceeds to step 915.

The predetermined value PIIAFBF is set to a value larger than the ΔPnApnp value for positions other than the first speed, which is obtained in step 913.

Next, in step 915, the intake pipe absolute pressure P1rc is added to the second subtracted value obtained in step 913 or 914, which is calculated in step 913 or 914.
[Difference from 1AP11 (P IIAT!!13-ΔpHA
FB) (hereinafter referred to as "feedback control start pressure") (step 915). If this answer is negative (No), that is, the intake pipe absolute pressure PnAye is the feedback control start pressure (P o^TRG-ΔI)l
lAPll), it is determined that open loop control should be performed and the process proceeds to step 916 and subsequent steps. That is, (P[1ATl!G-ΔPmouth^51))(P[1
When HacchoC≦(P[1^Tl!G-Δl'BAFB), oven loop control is executed (18th
Figure nomuhe~flea, 11 intervals).

In this step 91G, 1) (Similar to step 911, 1. FTlDL and Y timers are reset, and then it is determined whether or not the gear position is at the first speed position (step H)+7). If this answer is negative (NO), 1
-CU From the stored 1) v table, 11;;
Bulletin (subtraction term 1 for positions other than 1st speed, which will be described later, applied to open loop control according to the substitution Δl'RA)
"Find (step 918), step described below!]2
Go to 1.

FIG. 12 shows an example of this l)r table, and similarly to FIG. 10, the base (lq value Δp
HAI, Δr'n^2 is set and less than APIIAI,
Δ1〕Lo^1 or more -1-8P++Less than ^2 and Δ1) Mouth^
For 2 to 10, respectively [)■1 to [)T3 (1)
r+(1) "2(1)T3)" is set.

When the answer to step S]17 is 1° (Yes), that is, the gear position is at the first speed position 1if, IE C(
, + 9 II) FT child table et al. 01j
The subtraction term r for the first speed position is
apt is determined (step 919). Figure 13 is this 1
) An example of the FT child table is shown, and two base 1114 values Δ1)llAPI and ΔI'1lA are shown for the amount of change ΔPn^
F2 (>ΔPnApt) is set, ΔI'1lAF
less than I, less than ΔI′IIAFl and less than 1−ΔpHAF2, and Δ1)1(＾F2 and more than −1, respectively, I)FTI
~1) FT3 (1) pn (1) pr2 (1) p-r3)
is set.

In addition, the subtraction term 1) FT for the first speed position is the first speed position described above.
Subtraction term 1 for positions other than speed] is set to a larger value than T. As will be described later, the duty ratio Dvc during open loop control is determined by these subtraction terms L)T
, I) The larger the value of FT, the smaller the value is set, so as mentioned above, [[
By setting the DFT value to a value larger than the IDT value, the rate of increase in supercharging pressure when the transmission is in the first gear position can be controlled accordingly while directly grasping its actual transition. )1 can be done. Therefore, in conjunction with the setting of the reference value 1) v+;n described above, it is possible to reliably prevent the sudden increase in supercharging pressure and overboost in the first gear position (see Fig. 19). By controlling the rising speed of the supercharging pressure to a larger value at positions other than the first speed (solid line), desired acceleration characteristics can be obtained (broken line in the figure).

Next, set the subtractive rectification T to the memorized DFT value! +20), in step 921, it is determined that open loop control should be executed and the program is terminated.

11; Step 1 [The answer to 115 is +'r constant (Ycs)
, that is, when the intake pipe absolute pressure P[1AT (: exceeds the feedback control start pressure (Pn^DingI!G-ΔI)llAPll), 1. After the FBIIL 1 timer is reset,
Predetermined time 1. It is determined whether or not F old play Y has elapsed (step 22). If the answer is negative (No), proceed to step 9!7 and perform open loop control, while if 11r is constant (Yes), it is determined that feedback il and II control should be performed (step 1). Proceed to step 23. In this way, the absolute pressure inside the intake pipe Pn^r
e is the feedback control start pressure (1'n^TPG-Δ1
) mouth ^F1)! Instead of performing feedback control immediately when the rotation occurs, starting from this time, the predetermined period of time 1. F
Open loop control is executed until IIILY has elapsed (181st (Q 1.
1), feedback control is executed for the first time after lapse of time (after LC in the figure).

1); In step 923, the initial value of the integral control term Dvi is calculated according to the following equation (1).

1) vi=Kvr^XI)vcr+X (KvREpi
j −1)−(+) where KvR+: pij is f5
This is a learning correction coefficient calculated during feedback control according to the program shown in FIG. 4 as described later.

Next, the process proceeds to step 903, where it is determined that feedback control should be performed and the program is ended.

Return to the program in Figure 4 and step 40G in +1:1.
In the subsequent step 407, it is determined whether or not the 91st FJ subroutine executed in step 406 has determined that open loop control should be performed.

If this answer is negative (No), that is, it is determined that feedback control should be performed, the absolute pressure in the intake pipe is calculated from the PnArit; 1); J. 11+: Tlit' (step 408 to read P n^T2Q).

FIG. 14 shows an example of this PnAtgc map. Just like the KVT^ map, the base 1115 value Nv+-NV20 of the engine speed Na and the reference value 'AVl~l'^v8 of the intake temperature 1'A are By using such a map, it is possible to set the target value Pn^1'RG more accurately.

Next, in step 409, it is determined whether the gear position is in the first gear position, and when it is in the first gear position, a predetermined value P nAytcp is subtracted from the 1-1 mark 41αP8^TRG obtained in step 408. (Step old O), 1
After resetting the first target value PoAtta, if the vehicle is in a position other than the first speed, the process directly proceeds to step 411. In this way, 1] target value P nAy*c is smaller when the gear position is in the first gear position than when it is in a position other than the first gear position.
It is set to a smaller value by a predetermined value PnAy*cp.

By setting target value PIIATRc like this, when the transmission is in the first gear position, the boost pressure in the steady state can be controlled to a smaller value (solid line in Figure 19), and the torque applied to the gear can be suppressed. , its -H durability can be improved, and the number! When the engine is at a position other than the high speed, a higher desired boost pressure can be obtained in a steady state (see the dashed line).

In this step 411, step 408 or /1
Deviation ΔP s (= P BAT
RO-P BATC), and then the deviation Δ1)B
The absolute value 1ΔPal of is the predetermined value Gsi (for example, 20 a
sllg) or higher (step 41).
2). This predetermined value Gai is a dead zone defining pressure during feedback control.

The answer to step 412 is affirmative (Yes), that is, 1ΔP
When nl≧G++i holds true, constants KVP and νj of the proportional control term 1)vr and integral control term Dvi are read from the KVP table and Kvi table stored in the ECU 9, respectively, according to the engine speed Ne. (Step 4■3). Figure 15 and 161'XI
are diagrams showing examples of the Kvr table and Kvi table, respectively. That is, in the KVP table,
Two bases 11S (〆(NK
VP'l and NKVP2 (>NKVPI) are set, and the constant KVP is less than NKVP1, NKVP1 or more NK
KV for vr less than 2 and NKVP 2 or more, respectively.
PI-KVP3 (KVPI<KVP2< KVP3)
In addition, in the Kvi table, two reference values NKvii are set for engine speed NB.
and Nxvi2()Nxvi+) are set, and the constant Kv
i is Kvis~ for less than NKvi+, less than J2Nrvi2 than NKvit, and j- less than NKvi2, respectively.
Kvi3 (Kvi3 (Kvi + (Kvi 2)).

Next, the proportional control term 1)vr is changed to the constant Kv obtained above.
Set the product Kvr ・ΔPB of r and the deviation Δ1)8 in step 414), and the integral control term 1)vi,
The product K of the stored constant Kvi and the deviation Δf)n
vi・Δ [integral 1ν calculated up to Flo and +iif times
Control term 1) Sum with vi (= I) vi + Kvi ・
Δ1) is set to B) (step 415).

Next, the proportional and integral control terms 1) VP and 1) vi set above are applied to calculate the duty ratio 1) va during feedback control according to the following equation (2) (step 41G).

Dva=Dvar+X KVTA+ Dvr+ Dvi
=-(2) Next, the calculated duty ratio Dva
Check the limit of the duty ratio DVO.
is maintained at a value within a predetermined range (step 417), and a drive signal based on the duty ratio Dva is output to the control valve 18 (step 418), and the tree program is terminated.6 If the answer to step 412 is negative (No) , that is, 1ΔPa
1 G old is established, therefore 1:1 standard gf1P BA
TI! When Q and the actual intake pipe absolute pressure Pg^TO almost match, the proportional control term DVP is set to the value 0.0, and the integral control term 1)vi is set to its +)ij ILiI Wi D
Set each to v i (step/IHJ, 4
20).

Next, it is determined whether the gear position is at the first speed position (step 421), and if it is at a position other than the first speed,
Calculate the coefficient KVR according to the following equation (3) (step 4
22).

1 (VTAX l)v++n+ DviKv””K
VTAX DVGM "" 3) This coefficient Kvg represents the deviation in boost pressure control due to variations due to mass production or changes over time.

Next, the above coefficient Kvl! Learning hli positive coefficient Kv using
gεFIJ is calculated according to the following equation (4). (Step 423).

...(4) Here, the second term on the right side, K V RE F i , j 11
1T is the learning supplement 1 [coefficient obtained up to 1); depending on the engine speed Ne and the intake temperature
It is read from the KvRtr map described later. Also, Δ
is a constant, and CVREF is a variable that is experimentally set to an appropriate value between 1 and .

Kvt! according to the value of variable C1EF! K for εFiJ
vl! Since the ratio of values changes, this CVREF value is
The optimum Kv++εF1j can be obtained by setting an appropriate value within the range of 1): 1 to A in 1) according to the use of the target boost pressure control device, engine, etc.

Next, the calculated learning correction coefficient KvREFij
is stored in the KVREF map provided in the backup [≧AM in the ECLJO (step 424), and the steps from step 6 onward are executed to terminate this program. FIG. 17 shows an example of this t(vgEp map).

That is, KVI! EF map is 1);j memory VTA map (Figure 8) and P++^rl! Similar to the G map (Fig. 14), it is divided into a plurality of regions depending on the engine speed Nc, intake if, and J i'^, and Kvi! EFiJ values are calculated and stored.

If the answer to step 407 is r'F fixed (Yes), that is, it is determined that open loop control should be performed by the subroutine of FIG. 9, then 1);
From the F map, depending on the engine speed Ne and intake temperature '1゛^, learning supplement 1 [-coefficient Kvl! εFij is read (step 425), and then both the proportional control term Dvr and the integral control term Dvi are set to a value of 0.0 (step/126.427).

Next, the duty ratio f) during open loop control
Calculate vc according to the following equation (5) (step 428)
.

Dvc=Kvt^XKvRp: pijX (1) VG
M-Dr) - (5) Here, DT is the subtraction term set in step 918 or 1) 20 of the subroutine of FIG.

Next, perform a limit check of the calculated duty ratio 1)vc, for example, set the Dvc value to 0% or more:
, keep the value below 100% Step/12! ])
, execute step 8 above and terminate this program.

(Effects of Gummy Light) As detailed above, the present invention provides the following seven effects.

According to claim 1, when the transmission is in the low gear position, the ityr1 speed of the supercharging IF in the transient state is suppressed according to the actually detected "-H speed," so that the 11. Reliably prevents sudden changes in boost pressure and overboost. It is possible to improve the acceleration characteristics in the direction of -1.

Further, according to claim 2, when the supercharging pressure is controlled by controlling the opening degree of the movable vane, the supercharging pressure when the transmission is in the low speed gear position can be suppressed as a whole, and therefore in a transient state. By preventing a sudden increase in supercharging pressure and overboosting, the acceleration characteristics can be improved.

Furthermore, according to claim 3, when the supercharging pressure is controlled by controlling the opening degree of the movable vane, the supercharging pressure in a steady state when the transmission is in a low speed gear is controlled to a smaller value. , the torque applied to the gear can be suppressed, and therefore its durability can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an overall configuration diagram of a control device for an internal combustion engine equipped with a turbocharger to which the control method of the present invention is applied; Figure 3 is a view taken from III-III in Figure 2 to the turbine casing side, Section 41, Sentence 1, is a flowchart of the program for calculating the duty ratio Ov+: of the control valve, and Figure 5 is the duty ratio r)vc. Group of /11
A diagram showing a map of 1-value Dvc11, FIG. 6 is a flowchart 1 of the subroutine for determining the gear position of the transmission, FIG. 7 is a diagram showing a VF child table applied to the subroutine of FIG. 6, and FIG. 8 shows the map of intake 11, L hli lI-coefficient 1g VTA 1) 1, m 9 Figure i; i
Flowchart 1 of the open-loop system (wholesale region determination subroutine) executed in step 406 in FIG. 4, and FIG.
Figure 11 is a diagram showing a table of PIIAFB to the second subtraction value for positions other than the first speed.
Fig. 12 shows a table of subtraction term 1) T for positions other than 1st speed, Fig. 13 shows a table of subtraction term DFT for 1st speed position, and Fig. 14 shows a table of subtraction term 1) T for positions other than 1st speed. Target value PoAr
Figure 15 is a diagram showing the constant 1 of the proportional control term DVP (VP table, Figure 16 is the integral control term 1) table of the constant Kvi of vi, Figure 17 is a diagram showing the constant Kvi of the proportional control term DVP. Nli positive coefficient KVI! A diagram showing a map of EF, Figure 18 is a diagram showing the relationship between intake pipe absolute pressure P[1ATC and boost pressure control, and Figure 19 is a diagram showing boost pressure characteristics depending on the gear position of the transmission. be. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 4... Turbocharger (supercharger), 2... Intake pipe absolute pressure (P BATC) sensor, 14... Engine rotation speed (NO) sensor, 24...
...Vehicle speed (V) sensor, 61...Turbine wheel (
turbine), 64...movable vane, PIIATc...
・Intake pipe absolute pressure (supercharging pressure), ΔPn^... Change in intake pipe absolute pressure ρRATe (rate of rise), I) v++n
...Basic 2111 value of duty ratio Dva (basic supercharging pressure control 1 wholesale ff1), I' nAt1! a- Absolute pressure in the intake pipe 1) Target value of 11^Te (■Standard charge pressure). Applicant: Tree ([1 Giken Kogyo Co., Ltd.

Claims (1)

[Claims] 1. The rate of increase in supercharging pressure by a supercharger of an internal combustion engine is detected, and when the transmission is in a low gear position, the supercharging in a transient state is higher than when the transmission is in another gear position. A method for controlling boost pressure of an internal combustion engine, characterized in that the rate of increase in pressure is suppressed. 2. In a method for controlling boost pressure of an internal combustion engine, which controls the opening degree of a movable vane arranged on the turbine inlet side of a supercharger based on a basic boost pressure control amount depending on the operating state of the internal combustion engine. A supercharging pressure for an internal combustion engine, characterized in that when the transmission is in a low gear position, the basic supercharging pressure control amount is reduced so that the supercharging pressure is lower than when the transmission is in other gear positions. control method. 3. When the internal combustion engine is operating in the boost pressure feedback control region, the opening degree of the movable vane installed on the turbine inlet side of the turbocharger is adjusted according to the deviation between the actual boost pressure and the target boost pressure. A method for controlling the boost pressure of an internal combustion engine, wherein the target boost pressure is lowered when the transmission is in a low gear position than when the transmission is in another gear position. control method.