JPH0267446A - Internal combustion engine torque fluctuation detection device - Google Patents

Abstract

PURPOSE:To obtain proper torque fluctuation quantity even in the transient state of an engine to control the engine according to torque fluctuation quantity by considering the lowering quantity of torque in relation to a specified torque, the torque of one cycle before, for example as the quantity of torque fluctuation. CONSTITUTION:A torque detecting means (a) is to detect the torque TRQ of an engine, and a torque memory means (b) is to store the torque TRQ detected by the torque detecting means (a). A torque lowering quantity operating means (c) is to operate the torque lowering quantity TRQ of detected torque TRQ0 in relation to the specified cycle of an engine, i. e., the torque TRQ of one cycle before, for example, to consider this torque lowering quantity DELTATRQ as the torque fluctuation quantity. That is, since torque fluctuation quantity is considered to be the specified frequency of the engine, i.e., the torque lowering quantity in relation to the torque of one cycle before, for example, proper torque fluctuation quantity can be obtained instantly in the case where the engine is in a transient state.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a torque fluctuation amount detection device for an internal combustion engine.

[Conventional technology]

Detects the torque fluctuation amount of the internal combustion engine and adjusts engine control factors such as fuel injection amount, ignition timing, exhaust gas recirculation (EGR)
It is already known to control the amount etc. (Reference: JP-A-60-122234, JP-A-60-104754)
For example, lean burn controls the fuel injection amount so that the amount of torque fluctuation becomes a predetermined value (lean limit value), thereby preventing exhaust pollution and improving fuel efficiency without using a lean mixture sensor. system has been established (Reference: Japanese Patent Laid-Open No. 60-12
2234), as a method for detecting the amount of torque fluctuation described above, there is a method of detecting the torque of each cycle of the engine, calculating the variance of the torque over a predetermined number of cycles, for example, 50 cycles, and using it as the amount of torque fluctuation (see : JP-A-60-1
50446), but as mentioned above, 5
If the amount of torque fluctuation is obtained by distributed calculation every 0 cycles, the acquisition of the amount of torque fluctuation will be delayed, and as a result, the fuel injection amount of the engine will be changed and controlled every cycle of the engine.
Even if there is a large amount of torque fluctuation in the middle of the 50th cycle, the engine cannot respond instantaneously, resulting in a delay in engine control, resulting in poor emissions, poor drivability, poor fuel efficiency, and the like.

For this reason, the applicant has already proposed calculating a torque annealing value (or average value) and using the amount of decrease in torque from the annealing value as the torque fluctuation amount (see: Japanese Patent Application Laid-Open No. Publication No. 63-140848).

[Problem to be solved by the invention]

However, as mentioned above, when calculating the amount of decrease in torque from the torque annealing value, the annealing value lags behind the ever-changing driving conditions, and as a result, it still remains difficult to calculate the amount of decrease in torque from the torque annealing value. In this case, it is not possible to obtain an accurate torque fluctuation amount, and therefore, when applied to engine control using the above-mentioned torque fluctuation amount, there is still a problem that the engine control is not appropriate.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a torque fluctuation amount detection device for an internal combustion engine that can obtain an appropriate amount of torque fluctuation without delay even in a transient state of the engine.

[Means to solve the problem]

A means for solving the above problem is shown in FIG.

That is, the torque detection means detects the torque TRQ of the engine, and the torque storage means stores the torque TRQ detected by the torque detection means.

As a result, the torque reduction amount calculation means calculates the torque reduction amount ΔTRQ of the torque TRQ detected by the torque detection means from the torque TRQO of a predetermined cycle of the engine stored by the torque storage means, for example, one cycle,
This torque reduction amount ΔTRQ is taken as the engine torque fluctuation amount.

[For production]

According to the above-mentioned means, since the amount of torque fluctuation is the amount of torque decrease from the torque before a predetermined number of engine cycles, for example, one cycle, when the engine is in a transient state, an appropriate amount of torque fluctuation can be obtained instantaneously. .

〔Example〕

FIG. 2 is an overall schematic diagram showing an embodiment of an air-fuel ratio control device for an internal combustion engine according to the present invention. In FIG. 2, a pressure sensor 3 is provided in an intake passage 2 of an engine body 1. As shown in FIG.

The pressure sensor 3 directly measures the absolute pressure PM of the intake air pressure, and is, for example, a semiconductor type sensor, and generates an analog voltage output signal corresponding to the intake air pressure. This output signal is supplied to an A/D converter 101 with a built-in multiplexer of the control circuit 10. The distributor 4 includes a crank angle sensor 5 whose axis generates a reference position detection pulse signal every 720 degrees in terms of crank angle, and a crank angle sensor 5 which generates a reference position detection pulse signal every 30 degrees in terms of crank angle. A crank angle sensor 6 is provided which generates a signal. The pulse signals of these crank angle sensors 5 and 6 are supplied to the input/output interface 102 of the control circuit 10, and the output of the crank angle sensor 6 is sent to the CPU.
103 interrupt terminal.

Further, the intake passage 2 is provided with a fuel injection valve 7 for supplying pressurized fuel from a fuel supply system to the intake port for each cylinder.

Further, a water temperature sensor 9 for detecting the temperature of cooling water is provided in the water jacket 8 of the cylinder block of the engine body 1. Water temperature sensor 9 indicates cooling water temperature TH
Generates an analog voltage electrical signal according to W. This output is also supplied to the A/D converter 101 of the control circuit 10.

Reference numeral 11 denotes a heat-resistant piezoelectric combustion pressure sensor that directly measures the cylinder pressure in the cylinder of the engine, for example, the first cylinder, and generates an analog voltage electrical signal corresponding to the cylinder pressure. This output is also supplied to the A/D converter 101 of the control circuit 10.

The exhaust system downstream of the exhaust manifold 12 is provided with a catalytic converter 13 that accommodates a lean NOx catalyst that purifies the harmful component NO8 in the exhaust gas. The reason why a three-way catalyst for simultaneously purifying harmful components 11c, CO, and NO is not used is because the engine is a lean burn system, so there is little need to purify IC and CO acid components.

The control circuit 10 is configured as a microcomputer, for example, and includes an A/D converter 101, an input/output interface 102, a CPII 103, and an RO) 1104.
A RAM 105, a backup RAM 106, a clock generation circuit 107, and the like are provided.

In addition, in the control circuit IO, a down counter 108,
Flip-flop 109 and drive circuit 110 are for controlling fuel injection valve 7. That is, in the routine described later, when the fuel injection amount TAU is calculated, the fuel injection amount TAU is preset in the down counter 108 and the flip-flop 109 is also set. As a result, the drive circuit 110 starts energizing the fuel injection valve 7. On the other hand, the down counter 108 receives the clock signal (
(not shown), and finally the carrier terminal is “
1" level, the flip-flop 109 is set and the drive circuit 110 stops energizing the fuel injection valve 7. In other words, the fuel injection valve 7 is energized by the above-mentioned fuel injection amount TAU, and therefore , an amount of fuel corresponding to the fuel injection amount TAU is sent into the combustion chamber of the engine body 1.

Note that the interrupt generation of the CPU 103 is caused by the A/D converter 1.
When the A/D conversion of 01 is completed, the input/output interface 10
2 receives a pulse signal from the crank angle sensor 6, receives an interrupt signal from the clock generation circuit 107, etc.

The intake air pressure data PM of the pressure sensor 3 and the cooling water temperature data T)IW of the water temperature sensor 9 are taken in by an A/D conversion routine executed at predetermined time intervals and stored in the RAM 105.
is stored in a predetermined area. That is, data Q and THW in RAM 105 are updated at predetermined intervals. Further, the rotational speed data Ne is calculated by interrupt every 30° CA of the crank angle sensor 6 and stored in the RAM 10.
5 is stored in a predetermined area.

The operation of the tiIIIWJ circuit 10 shown in FIG. 2 will be described below.

FIG. 3 shows an average effective torque calculation routine, which is executed at predetermined intervals. That is, the routine in FIG.
Multiple crank angle positions shown in the figure ATDC5°C^ (5° after top dead center), ATDC20°CA, ATDC
Calculate the combustion pressures Pl+P, , P, , P at four points: 35° CA, ATDC 50° CA, and use the average effective combustion pressure obtained by adding these instantaneous combustion pressures as the torque substitute value PTRQ. It is. This calculation method has already been disclosed by the applicant in Japanese Patent Application Laid-Open No. 63-61.
This is proposed in Publication No. 129.

That is, in steps 301 to 305, the crank angle position is BTDC 160°C^ (160° before top dead center), A
TDC5°C^, ATDC20°CA, ATDC
Determine whether it is 35° CA or ATDC 50° CA. If not at any crank angle position, step 3
Proceed directly to step 17.

If the crank angle position BTDC is 160°C^, the process proceeds to step 306, where the combustion pressure of the combustion pressure sensor 11 is A/D converted and taken in. and stores it in the RAM 105.

Note that the value V near the intake bottom dead center is used as a reference value for combustion pressure at other crank positions in order to absorb output drift due to temperature of the combustion pressure sensor 11, variations in offset voltage, etc. .

If the crank angle position is ATDC5°C^, step 3
07, the combustion pressure of the combustion pressure sensor 11 is A/D converted and taken in as V. Next, in step 308, the value P + (= V r V.) obtained by subtracting the reference value V is obtained. RAM 1 calculated as combustion pressure at ATDC 5°CA
Store in 05.

If the crank angle position is ATDC20°CA, the process proceeds to step 309, where the combustion pressure of the combustion pressure sensor 11 is A/D converted and taken in as v2.Next, in step 310, the reference value V is subtracted from the value Pg. (=Vt Vo) as ATD
RAM 105 calculated as combustion pressure at C20°CA
Store in.

If the crank angle position is ATDC 35° CA, the process proceeds to step 311, where the combustion pressure of the combustion pressure sensor 11 is A/D converted and taken in as V.Next, at step 312, the reference value ■ is obtained. The value Ps (=V: + VO) obtained by subtracting
Calculated as combustion pressure at DC 35°C^ RAM 10
Store in 5.

If the crank angle position is ATDC 50° C^, the process proceeds to step 313, where the combustion pressure of the combustion pressure sensor 11 is A/D converted and taken in as v4.Next, at step 314, the reference value ■ is obtained. The value obtained by subtracting P4 (=V4 VO) is ATD
RAM 105 calculated as combustion pressure at C50°CA
Store in. Next, in step 315, the average effective torque value TRQ is calculated as follows: TRQ ←0.5・p, + 2.0−pz+ 3.0・P3+
4.0-p4, and then, in step 316, the torque fluctuation amount ΔTRQ is calculated. Note that step 31
6 will be described later.

The routine then ends in step 317.

Although the routine shown in FIG. 3 is configured to be executed at predetermined intervals, in reality, three of the crank angle sensors 6
This is done by the 30° CA interrupt routine which is executed by the interrupt of the 0'' CA signal.

In this case, as shown in Fig. 4, an angle counter NA is provided which is cleared in response to the 720° CA signal and counts up every 30° CA interrupt, and the combustion pressure is adjusted to A/A according to the value of the angle counter NA. However, the positions of ATDC5°CA and ATDC35°CA do not match the 30''C^ interrupt time. Therefore, the ATD
C5°CA, ATDC35" A/D conversion at CA is performed at the immediately preceding 30" CA dino inclusion point (NA-"0""
This is done by calculating the 15° CA time in step B), setting it in a timer, and causing the CPU 103 to interrupt the timer.

Further, although combustion pressure is used as the average effective torque value, it can also be directly obtained by providing a torque sensor.

FIG. 5 is a detailed flowchart of the torque fluctuation amount calculation step 316 in FIG. That is, step 501
Then, the value P of the average effective torque value PTRQ one cycle before
Calculate the amount of decrease ΔTRQ from TR port 0.

In other words, ΔTRQ −TRQO−TRQ. In step 502, in preparation for the next execution, TRQ
Let be TRQO.

In step 503, it is determined whether the torque reduction amount ΔTRQ is positive or negative. That is, when the torque decrease amount ΔTRQ is negative, in other words, when the torque increases, the torque value TRQ is assumed to be changing along the ideal torque, and in step 505, the torque value TRQ is set as the torque fluctuation amount. Let the value ΔTRQ be 0.

On the other hand, when the torque decrease amount TRQ is positive, in other words, only when the torque decreases, it is considered that a torque fluctuation has occurred, and the value ΔTRQ is regarded as the torque fluctuation amount. Since the torque also decreases, deceleration processing is performed in step 504. In other words, during deceleration, it is impossible to distinguish between a decrease in torque due to a decrease in the amount of intake air and a decrease in torque due to deterioration of combustion. This is what I did.

In step 506, an air-fuel ratio correction coefficient FAF is calculated based on the torque fluctuation amount ΔTRQ. Note that step 506 will be described later.

This routine then ends in step 507.

FIG. 6 is a detailed flowchart of the deceleration process step 504 in FIG. That is, in step 601, it is determined whether the torque fluctuation it (amount of decrease) ΔTRQ is larger than a predetermined value X1, and in step 602, ΔTRQ>X,
The number of times CNT that the state appears consecutively is counted. As a result, only if the state of ΔTRQ>X continues for X2 or more times, the flow of step 603 proceeds to step 604,
Set the deceleration flag FD (FD="l"), on the other hand,
If ΔTl2O≦X, the flow at step 601 proceeds to step 605, where the counter CNT is cleared and
Further, in step 606, the deceleration flag FD is reset (FD=1101'').

This routine then ends in step 607.

Note that the value X2 at step 603 is, for example, 3.

FIG. 7 is a detailed flowchart of the FAF calculation step 506 of FIG. That is, in step 701,
It is determined whether or not it is in a deceleration state (FD="B"). If it is not in a deceleration state, the process proceeds to step 702, and if it is in a deceleration state, it directly proceeds to step 705.

Next, in step 702, it is determined whether the torque fluctuation amount ΔTRQ is larger than the set value X. As a result, if it is larger than the set value
Make TRQ approach the set value X. On the other hand, if it is smaller than the set value
RQ is set to X.

Try to get closer to.

The routine then ends at step 705.

Note that the torque fluctuation amount ΔTRQ in step 702 may be an average value of several cycles or 10 cycles to the extent that the delay does not become large. Further, the set value X may be variable depending on the operating state of the engine, the environmental state, etc.

FIG. 8 shows an injection amount calculation routine, which is executed at every predetermined crank angle, for example, every 360" CA. Step 8
01, the intake air pressure data PM is stored in the RAM 105.
and the rotational speed data Ne to read out the basic injection amount TAU.
Calculate P. In step 802, the final injection amount TAU
, TAU -TA [IP -FAF ・α +
Calculate by β. Note that α and β are correction amounts determined by other operating state parameters, such as a signal from a throttle position sensor (not shown), a signal from an intake air temperature sensor, battery voltage, etc. These are also correction amounts determined by RAM. 105. Next, in step 803, the injection 11TAU is set in the down counter 108 and the flip-flop 10 is set.
Set 9 to start fuel injection. The routine then ends at step 804. As described above, when the time corresponding to 11 TAU of injection has elapsed, the flip-flop 109 is reset by the carrier signal of the down counter 108, and the fuel injection ends.

FIG. 9 is a timing diagram for explaining the present invention in detail. That is, the intake air pressure PM changes as shown in FIG. 9(A), and as a result, the ideal torque ITR, the torque TRQ for each cycle, and the average torque value TRQ (
For example, assume that the number of cycles (for example, 50 cycles) changes as shown in FIG. 9(B). In this case, the actual torque fluctuation amount will be as shown in FIG. 9(C). On the other hand, according to the present invention, since the torque fluctuation amount is the amount of decrease in the current torque detection value from the torque detection value one cycle before,
The result is as shown in FIG. 9(D), which is close to the actual torque fluctuation amount shown in FIG. 9(C). Note that during deceleration, the amount of torque fluctuation according to the present invention is larger than the actual amount of torque fluctuation, but in this case, the deceleration flag FD is set by the deceleration process.
is set to "1" and engine control is stopped.

As in the past (Japanese Unexamined Patent Application Publication No. 63-140848), if the amount of torque decrease from the average torque value (smoothed value) is the amount of torque fluctuation, as shown in Figure 9 (E), during acceleration, the average Due to the delay in value calculation, the amount of torque fluctuation is hardly detected, and moreover, the amount of torque fluctuation during deceleration becomes excessive.

In addition, in the above-mentioned embodiment, the torque fluctuation amount detection device for one cylinder is shown, but when controlling multiple cylinders independently, it is easy to detect the torque fluctuation amount for each cylinder. be.

Further, in the above embodiment, the fuel injection amount is controlled based on the amount of torque fluctuation, but the ignition timing, the EGR amount, etc. may also be controlled.

Furthermore, in the above embodiment, the fuel injection amount is calculated according to the intake air pressure and the engine rotation speed, but the fuel injection amount is calculated according to the intake air amount and the engine rotation speed, or the throttle valve opening and the engine rotation speed. The fuel injection amount may also be calculated.

Further, in the above embodiment, an internal combustion engine is shown in which the amount of fuel injected into the intake system is controlled by a fuel injection valve, but the present invention can also be applied to a carburetor type internal combustion engine. For example, an electric air control pulp (EACV) is used to control the air-fuel ratio by adjusting the intake air amount of the engine, and an electric bleed air control pulp is used to adjust the amount of air bleed from the carburetor to control the main system passage and slow. The present invention can be applied to devices that control the air-fuel ratio by introducing atmospheric air into system passages, devices that adjust the amount of secondary air sent to the exhaust system of an engine, and the like. In this case, the basic fuel injection amount corresponding to the basic injection flTAUP in step 801 is determined by the carburetor itself, that is, it is determined according to the intake pipe negative pressure according to the intake air amount and the engine rotation speed, and the basic fuel injection amount corresponding to the basic injection flTAUP in step 802 is determined. The amount of supplied air corresponding to the final fuel injection ITAU is calculated.

〔Effect of the invention〕

As explained above, according to the present invention, since the amount of torque variation is the amount of torque decrease from the torque before a predetermined cycle, for example, one cycle, an appropriate amount of torque variation can be obtained even in a transient state of the engine. Appropriate control can be obtained when applied to engine control based on quantity.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram for explaining the present invention in detail; FIG. 2 is an overall schematic diagram showing an embodiment of an air-fuel ratio control device for an internal combustion engine according to the present invention; FIGS. 3 and 5; 6, 7, and 8 are flowcharts for explaining the operation of the control circuit in FIG. 2; FIG. 4 is a timing diagram for supplementary explanation of flowchart 1 in FIG. 3; The figure is a timing diagram illustrating the invention in detail. l... Engine body, 3... Pressure sensor, 4... Distributor, 5.6... Crank angle sensor, 10... Control circuit, 11... Combustion pressure sensor, 12... Catalyst converter.

Claims (1)

[Scope of Claims] 1. Torque detection means for detecting the torque of an internal combustion engine; Torque storage means for storing the torque detected by the torque detection means; and a predetermined cycle of the engine stored by the torque storage means. a torque reduction amount calculation means for calculating an amount of torque reduction of the torque detected by the torque detection means from the previous torque; Quantity detection device.