JPS58195056A - Exhaust recirculation controlling method - Google Patents

Abstract

PURPOSE:In an internal-combustion engine equipped with an automatic speed change gear having a lockup mechanism, to prevent the deterioration of drivability during lockup by lowering EGR upon locking up of said gear in the low speed rotary region of engine. CONSTITUTION:EGR control valve 24 provided in EGR path 23 is controlled to produce the optimal EGR in accordance to each operating parameter by means of a constant voltage controller 40 to be provided with the detected values from a suction air temperature sensor 28, throttle position sensor 29, water temperature sensor 30, O2 sensor 31, crank angle sensor 32, car speed sensor 35, etc. An electronic control section 40 will decide the speed change position and whether it is under lockup condition or not through the throttle opening and the function of a lockup device in an automatic speed change gear 36 while to lower EGR during lockup.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust recirculation control method for an exhaust recirculation internal combustion engine equipped with an automatic transmission having a device that directly connects the input side and output side of the automatic transmission.

Conventionally, in cars equipped with automatic transmissions, a torque converter is used as an intermediary in the power transmission device, so engine combustion fluctuations are absorbed by the torque converter, so that no signal is transmitted to the vehicle, and drivability does not deteriorate. On the other hand, 1 of the transmission system
In a dive where a coupling function is added to the gearbox, when the gearbox is directly coupled, it will be subject to engine combustion fluctuations in the same way as a gear transmission.

In conventional vehicles equipped with automatic transmissions with direct coupling devices, direct coupling of the transmission system was limited to high speeds, so engine combustion fluctuations were small and no special measures were required. In recent years, as a measure to improve fuel efficiency, the direct coupling function with high transmission efficiency has attracted attention in the low speed range or low gear direct coupling. With these types, deterioration in drivability when directly coupled is a problem, and improvements are needed.

The present invention adjusts the amount of exhaust recirculation in order to improve the performance in the low rotation range of an exhaust type internal combustion engine equipped with an automatic transmission with a direct coupling device. Case K is a book that provides an exhaust recirculation control method characterized by reducing the exhaust recirculation rate of an internal combustion engine.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.

FIG. 1 is a system diagram of an exhaust recirculation internal combustion engine equipped with a fuel injection device and equipped with an automatic transmission with a direct coupling device to which the present invention is applied. The air sucked from the air cleaner 1 is passed through an air flow meter 2, a throttle valve 5. The air is sent to the combustion chamber 8 of the internal combustion engine main body 7 via an intake passage 12 that includes a surge tank 4, an intake port 5, and an intake valve 6. The throttle valve 3 is linked to an accelerator pedal 15 in the driver's cab. The combustion chamber 8 includes a cylinder head 9, a cylinder block 10, and a piston 11.
The exhaust gas produced by combustion of the air-fuel mixture is discharged to the atmosphere through an exhaust valve 15, an exhaust port 16, an exhaust manifold 17, and an exhaust pipe 18. The intake system bypass passage 21 connects the upstream side of the throttle v9fs and the surge tank 4, and the bypass flow control valve 22 controls the flow passage area of the intake system bypass passage 21 to maintain a constant engine speed during idling. . An exhaust gas recirculation passage valve 23 that guides exhaust gas to the intake system in order to suppress the generation of nitrogen oxides connects the exhaust manifold 17 and the surge tank 4, and an on-off valve type exhaust gas recirculation control valve 24 controls the The exhaust gas recirculation passage 23 is opened and closed in response to the signal.

Measurements at each institution should be carried out by installing sensors suitable for each measurement. The intake air temperature sensor 28 is provided within the air flow meter 2 and detects the intake air temperature. A throttle position sensor 29 is installed on the throttle valve 3 to detect the opening of the throttle valve 3. A water temperature sensor 30 is installed on the cylinder block 10 to indirectly detect the cooling water temperature, that is, the engine temperature. An air-fuel ratio sensor 31 is connected to the exhaust manifold 17 as an oxygen concentration sensor.
It is attached to the collecting part of the exhaust gas and detects the oxygen concentration of the exhaust gas at the collecting part. The crank angle sensor 32 is provided on a power distributor 33 coupled to a crankshaft (not shown) of the internal combustion engine main body 7, and indirectly detects the angle of the crankshaft from the rotation angle of a shaft 34 of the power distributor 36. Vehicle speed sensor 35 is automatic transmission 36
is installed on the output width side of the output shaft to detect the rotational speed of the output shaft. The outputs of these sensors 2, 28, 29, 30, 31, 32.35 and the voltage of the storage battery 37 are transmitted to the electronic control unit 40. The electronic control section 40 calculates the control amount of each section based on these measured values, and transmits control signals as necessary.

In the fuel injection system, the fuel injection valve 41 corresponds to each cylinder,
Each pump 42 is provided near each intake port 5.
sends fuel from the fuel tank 45 to the fuel injection valve 41 via the fuel passage 44. The electronic control unit 40 calculates the fuel injection amount using the input signals from each of the sensors as parameters,
An electric pulse having a pulse width corresponding to the calculated fuel injection amount is transmitted to the fuel injection valve 41. Similarly, the electronic control unit 40 controls the bypass flow control valve 22 and the exhaust recirculation control valve 2.
4. Solenoid valve 45 (second
5) and the secondary side of the ignition coil 46, which controls the ignition coil 46, is connected to a power distribution 433.

As a direct connection device for the automatic transmission 36, a brake band type friction engagement device 50 is shown in FIG. 742 and FIG. A speed change valve 51 installed adjacent to a solenoid valve 45 for the hydraulic control circuit of the automatic transmission 36 receives pressurized oil from a manual valve (not shown) operated by a speed change lever in the driver's cab, and outputs it from an input port 52. The brake band 56 is operated by controlling the pressure oil flowing through the port 53 to the oil chamber 55 of the hydraulic servo 54. Speed change valve 5
1 has a built-in spool 57 for controlling the direction of pressure oil, and the spool 57 is connected to a solenoid valve 45.
A spring 58 is attached to a portion on the opposite side of the solenoid valve 45. The rod 59 of the solenoid valve 45 contacts the end of the spool 57 on the solenoid valve 45 side, and when the solenoid valve 45 is energized, the spool 57 is pushed toward the spring 58 side to change the oil path.

As shown in FIG. 2, the solenoid valve 45 is energized and the rod 59
When the spool 57 is displaced against the spring 58, the input port 52 and the output port 55 are disconnected, pressure oil is not supplied to the oil chamber 55 of the hydraulic servo 54, and the brake band 56 is held. become a state. Also, as shown in Figure 3, when the power to the solenoid valve 45 is cut off, the rod 59 is retracted into the solenoid valve 45, the spool 57 is moved toward the solenoid valve 45 by the spring 58, and the input port 52 and output port 53
is connected, pressure oil is supplied to the oil chamber 55 of the hydraulic servo 54, and the brake band 56 is released.

FIG. 4 shows a block diagram of the electronic control section 40 that controls the movements of each section as described above. The electronic control unit 40 includes a central processing unit 60 consisting of a microprocessor, a read-on memory 61, a random access memory 62, and another random access memory 63 as a non-volatile memory element that can be supplied with power from an auxiliary power source and retain memory even when the engine is stopped. , a multiplexed analog-to-digital converter 64, and a buffered output 465 are connected to each other via a multiplexed analog-to-digital converter 64, an air flow meter 2, an intake air temperature sensor 2,
B, the outputs of the water temperature sensor 30, air-fuel ratio sensor 31, and storage battery 37 are transmitted via each measurement cable. In the buffered input/output device 65, the outputs of the throttle position sensor 29 and crank angle sensor 32 are transmitted via respective measurement cables, and the bypass flow control valve 22, exhaust recirculation control valve 24, and fuel injection valve 4 are also transmitted.
1. A control signal is transmitted to the solenoid valve 45 and the ignition coil 46 via each transmission cable in response to a control command from the central processing unit 60.

Below, as a specific example of the exhaust recirculation control method using the above-mentioned control system, a method will be described in which the shift position signal of the automatic transmission is used as the identification signal, and the intake air amount and engine rotational speed are set to 4#.

In this control program, in order to process the observation of each measurement signal and the transmission of control signals in real time, the main routine uses the opening degree of the throttle valve 3 and the energization state of the solenoid valve 6 as input data, and uses the results to determine the shift position. In addition to determining the intake air amount and engine speed, it also captures various measurement signals such as intake air amount and engine speed, sets control conditions, and performs arithmetic processing, and interrupts at fixed time intervals.The interrupt routine identifies control conditions and performs exhaust gas recirculation. A control signal is sent to the control valve.

As shown in the fifth haze, in the main routine, after the start,
In step 1000, the throttle position sensor 29, which controls the opening of the throttle box 5 that adjusts the amount of intake electricity, is manually operated, and then in step 1010, the electric power W1 for the hydraulic control circuit of the automatic transmission 36 is applied.
1 valve 45 is retrieved from the main memory of the central processing unit. In step 1020, it is determined from the opening degree of the throttle valve 3 and the energization state of the solenoid valve 45 whether or not the shift position of the automatic transmission 56 is in a direct connection state. If it is in a direct connection state, the process proceeds to step 1030; The process branches to step 1040. In step 1030, the direct connection flag F1 is set to 1. On the other hand, in step 1040, the direct connection flag F1 is set to 0. Thereafter, the process proceeds to step 1050, where conditions for exhaust gas recirculation control are determined. In this step, for example, if exhaust recirculation is to be performed when the water temperature is 60°C or higher, the measurement signal from the water temperature sensor 50 is evaluated based on the judgment condition of 60°C, and if it is high, the process proceeds to step 1060, and if it is low, the process proceeds to step 1000. return.

In step 1060, the intake air flow rate Q from the air flow meter 2 and the crank angle AC from the crank angle sensor 52 are taken in as data. Next, the process proceeds to step 1070, where the engine rotation speed Ng is calculated by integrating the crank angle Acυ) reception time, and further the flow rate Q and the engine rotation speed Ng are calculated.
Calculate the ratio Q/Ng. In the next step 1080 (
i, control amount EGR of the exhaust recirculation control valve 24 = f (Q, N
g) is determined by interpolation from the discrete data Ng, Q/NR, and the determined value is recorded in the storage location EGR of the random access memory 62. In the next step 1090, it is determined whether the direct connection flag F1 defined in step 1030 or step 1040 is 1, that is, the direct connection state, and if F1=0, the process advances to step 1100, and F1=0.
If it is 0, the process returns to step 1000.

In step 1100, a correction coefficient A (≦1) is used to correct the amount of exhaust gas recirculation when the own transmission is directly connected.
is multiplied by the existing control amount EGR to correct the control amount EGR. The corrected control amount EGR is recorded again in the memory location EGR of the random access memory 62. After step 1100 is completed, the process returns to step 1000 and repeats each step of the main routine.

The interrupt routine interrupts every 4 milliseconds. When an interrupt is performed, first, in step 2010, the EGR counter EC is used to calculate the control time, as shown in the sixth line.
Add 1 to . Next, in step 2020, it is determined whether EC is larger or smaller than a preset coefficient B. If EC is less than B, jump to step 2050, and if EC is less than B.
If it is above, the process advances to step 2030. In step 2030, EC is returned to 0, and in step 2040, control flag F2 is set to 1. In step 2050, it is determined whether the control flag F2 is 1 or not, that is, whether the time to adjust the amount of exhaust gas recirculation has been reached.If F2=1, the process advances to step 2060; returns to the main routine. In step 2060-, according to the control amount stored in the random access memory EGR,
The exhaust gas recirculation control valve 24 is operated via the buffered inlet/outlet device 65. After operating the control valve 24, the control flag F2 is set to 0 in step 2070, and the process returns to the main routine. In the above explanation, the method for controlling exhaust gas recirculation was shown in the form of an independent program, but although it performs a wider range of control, It may be configured as one of the subroutines/subprograms, and the above control method can be converted into a subprogram almost as is. In addition, in the above method, the control amount is determined based on the intake air amount and engine speed, but it is also possible to base the control amount on the fuel injection amount, air-fuel ratio, or exhaust pressure by installing a new pressure sensor in the exhaust manifold. It would be an effective method.

The control range is set according to the characteristics of the power system, but in an extreme example, after the transmission is directly connected, the amount of exhaust recirculation is reduced, and eventually the amount of exhaust recirculation is reduced to zero. If the control range includes the case where the exhaust gas recirculation control valve is closed, this control method has a very wide control range.

As described above, with the control method according to the present invention, it is possible to change the engine control contents when the automatic transmission is directly connected and when it is not directly connected, and when it is not directly connected, fuel consumption and harmful gas emissions can be adjusted without considering drivability. When connected directly, the exhaust recirculation rate can be adjusted to improve power performance.

[Brief explanation of drawings]

Fig. 1 is a system diagram of an exhaust recirculation type internal combustion engine with a fuel injection device equipped with an automatic transmission with a direct coupling device to which the present invention is applied, and Fig. 2 is a brake band type friction engagement device showing a state in which the transmission is directly coupled. Figure 3 is a system diagram of the brake band type friction engagement device with the transmission not directly connected.
FIG. 4 is a block diagram of the electronic control device, FIG. 5 is a main routine for implementing the control method of the present invention, and FIG. 6 is an interrupt routine for implementing the control method of the present invention. 2... Air flow meter, 3... Throttle valve, 4...
・Surge tank, 17...Exhaust manifold, 23...Exhaust gas recirculation passage, 24...Exhaust gas recirculation control valve, 28...
・Intake temperature sensor, 29... Throttle position sensor, 3
0... Water temperature sensor, 31... Air-fuel ratio sensor, 32...
...Crank angle sensor, 33...Distributor, 34...
Axis, 35...Vehicle speed sensor, 36...Automatic transmission, 4
0...Electronic control unit, 41...Fuel injection valve, 45...
・Solenoid valve for hydraulic control circuit, 50...Friction engagement device, 5
1... Speed change valve, 60... Central processing unit, 61...
Read-on memory, 62... Random access memory, 63... Random access memory, 64...
Analog/digital converter with multiplexer, 65...
- Buffered input/output device, 66...pass. A... Correction coefficient, Ac... Crank angle, B... Coefficient, EGR... Control amount, EC... EGR counter,
F1... Direct connection flag, F,... Control flag, N
B...Engine speed, Q...Flow rate. Patent applicant Toyota Motor Corporation Sai5 Zusai6 ㅅ

Claims (1)

[Claims] (1) In an exhaust recirculation control method for an exhaust recirculation type internal combustion engine equipped with an automatic transmission having a device that directly connects the input side and the output side, when the automatic transmission is directly connected in the low speed rotation range of the internal combustion engine, the exhaust recirculation rate An exhaust recirculation control method characterized by reducing the