JPS62288349A - Engine control system - Google Patents

Abstract

PURPOSE:To control an engine with a high degree of accuracy, by providing a combustion condition control means for controlling the combustion condition of the engine and a changing means for changing the period during which outputs of sensors are averaged in accordance with the operating condition of the engine. CONSTITUTION:A pressure sensor 13 detects the pressure of a combustion chamber 3. A control unit 20 has an input section 23 and a drive circuit 24 for a fuel injection valve 24, and receives detection signals from sensors 1 through 17 including an air flowmeter 7, while delivers a drive signal to a fuel injection valve 9. A control unit 20 has a comparing means for comparing an averaged value of outputs from a sensor 13 during steady-state operation with an actual output value of the sensor 13, and a changing means for changing the period during which the above-mentioned averaged value is obtained, in accordance with the operating condition of the engine. Thus, the time for judging whether the operating condition of the engine is stable or not may be restrained to a minimum value, thereby it is possible to control the engine with a high degree of accuracy.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention has a sensor that directly detects the combustion state, and the combustion state is controlled according to the sensor output. ,
1ltll device.

(Prior art) Recently, in order to stably operate the engine, information on the combustion state in the cylinder is obtained directly using finger scraping, optical sensors, ion gaps, etc. Attempts have been made to change the parameters (for example, ignition B\11, air-fuel ratio, exhaust yA flow, etc.) (see, for example, Japanese Patent Laid-Open No. 147631/1983). By the way, in order to judge whether the engine operating state is stable or not, it is necessary to compare the current operating information during steady state with the previous operating information. When making such comparisons, the more past operating information you have, the more accurate judgments of engine operating conditions can be made;
When the operating condition is stable, the operating information l is lower than when the operating condition is unstable.
There is no need to get a lot of Ji. However, conventionally: Regardless of whether engine operation is stable or unstable,
The sampled driving information is constant, and the driving information end is at the minimum required predetermined 11JrM in an unstable state.
Therefore, it takes a lot of time overall to determine whether the engine operating state is stable, and it tends to be difficult to perform accurate engine control.

(Objective of the Invention) The present invention aims to minimize the time required to determine whether or not the engine operating state is stable by sampling operating information in a minimum period for each operating state, and to control the engine with good viscosity. An object of the present invention is to provide an engine control device that can perform the following operations.

(Structure of the Invention) The present invention provides an engine control device that has a sensor that directly detects the combustion state and controls the combustion state according to the output of the engine. a comparison means for comparing the value with the sensor output value during actual operation; a combustion state control means for controlling the combustion state of the engine based on the output of the comparison means; and a changing means for changing the information.

With this configuration, the combustion state is controlled based on a comparison between the average value of sensor output during steady operation and the sensor output value during operation, and the period 1g1 for calculating the above average value is changed depending on the operating state. Therefore, for each operating state, a minimum period of C operating information) is J-sibling.

(Embodiment) FIG. 1 shows an embodiment of the apparatus of the present invention. In this figure, an engine 1 shown at J3 has a cylinder 2, a combustion chamber 3 within the cylinder 2, and the like. An intake passage 4 and an exhaust passage 5 are connected to the upper engine 1. In the intake passage 4,
From the upstream side: 1 Acleaner 6, Airf [1-Meter 7]
, a throttle valve 8a3, and a fuel injection valve 9 are provided. An air-fuel ratio sensor 11 is provided in the exhaust passage 5 in the L direction of the exhaust purification device 10 . In addition to this, fuel injection! 8f
As a detection sensor necessary for controlling fl, there are a rotation speed sensor 12 that detects the engine speed based on changes in the crank angle of the engine 1, a pressure sensor 13 that detects the pressure inside the combustion chamber as a sensor that directly detects the combustion state, and a suction sensor 13 that detects the pressure inside the combustion chamber. An intake air temperature sensor 14 that detects the air temperature, a water temperature sensor 15 that detects the engine cooling water temperature, and a boost sensor 16 that detects the booth 1 to (intake negative pressure) are provided.

The control unit 20 includes a CI) tJ 21, a memory 22, an input section 23, a drive circuit 24 for the fuel injection valve 9, etc.
Detection signals from the air flow meter 7 and each sensor 11 to 15 are manually input to output a drive signal to the fuel injection valve 9. This drive signal is given by an injection pulse, and the pulse width of this injection pulse is The fuel injection fi (ffiFl supply at>) is controlled by.

In particular, the control-L unit 20 is a comparison means for comparing the average value of the output of the pressure sensor 13 during steady operation of the engine 1 and the output value of the pressure sensor 13 during actual operation, which is a feature of the present invention. and combustion state control means for controlling the combustion state of the engine based on the output of the comparison means, and changing means for changing the period for determining the average value according to the operating state. Flowchart 1 to 1 shown in FIG. 3 or 3 are controlled.

Next, referring to FIG. 2 /TX1)O-CH 11-,
1.a, II The initial characteristics of the control unit 20 will be explained.

In step S1, the ignition switch is turned on, and in step S2, the number N of samples of information regarding the combustion state (rotational speed, boost which is intake negative pressure, etc.) is counted.
The content j of the counter in the PU 21 is initially set to rOJ. Note that this number N is proportional to the air-fuel ratio. In step S3, the engine rotation speed rp+++ from the rotation speed sensor +J12 and the boost P b from the boost sensor 16 are received, and in step S4, the fuel injection amount Qf is determined based on the engine rotation speed rpm and the boost 1]b.
Calculate. In this case, the ripple number N is the rotational speed rpn+
, boost Pb1 fuel injection; is set in advance according to +tQf, stored in the memory 22 as a map, and the rotation speed r
In the relationship between pl and boost l) b, the rotation speed rpn+
The smaller a3 and boost Pb are, the larger they are set. That is, the number of samples N becomes large when the load is low and the rotation is low, and becomes small when the PJM is high and the rotation is high. Further, the number of samples N is set to increase as the air-fuel ratio increases. In step S5, the number N stored in the memory 22 in advance is read out. The processing of step S4 and step Sb serves as a changing means.

Step 88'C determines whether or not the rotational speed rpl is greater than the predetermined rotational speed 01 in order to determine whether the engine 1 is started.31 When the rotational speed rpm is less than or equal to the predetermined rotational speed C1, the engine 1 is in the starting state. It is determined that step S;+
1. : The transitional fuel injection amount Q" is increased by the fuel injection amount ΔQf3 corresponding to the starting increase hl. In step S8, fuel injection is performed with the increased fuel injection IQ+', thereby causing the engine 1 to change from the starting operating state to a steady state. Move to operating state or transient operating state.

- When the engine 1 enters a steady operating state or a transient operating state, the rotational speed rpm in step S6 becomes larger than the predetermined rotational speed C1, and the process moves from step S6 to step S9. In step S9, in order to determine whether the engine 1 is in a steady operating state or a transient operating state, it is determined whether the rotational speed change amount Δrpi is smaller than a predetermined value ε1, and the rotational speed change amount Δrp+m is determined. When the predetermined value is 81 or more, it is determined that there is a transient operation state, and the transition is made to step S+o9. Also, when the amount of change in the rotation speed p+n is smaller than the predetermined value ε1, the step is changed to step S9. Tsubu 5-
11, it is determined whether the boost change amount Δ[)b is smaller than a predetermined value 1nε2, and when the boost change amount ΔPb is equal to or greater than the predetermined value 82, it is determined that the engine 1 is in a transient operating state, and the process moves to step S10. 1. Step S +oct
1. The counter contents are initialized to IO, and in step Sη, the fuel injection amount Qf is increased by the maximum fuel injection change ΔQf2 corresponding to the acceleration increase 1i. At step $8, fuel injection is performed with this increased fuel injection PfiQI', and the engine 1 shifts from the transient operating state to the steady operating state.

When the engine 1 enters the steady operating state, the process moves from step S8, step S3, step S4, step S8, step Ss, and step S11 to step S. In step St1, the counter content j is incremented. In step S14, it is determined whether the incremented counter content jffi is greater than or equal to the number number N.
Step S1 when counter content j is greater than or equal to the number of samples N
5, the number of variances n of the degree of dispersion Aj, which will be described later, is set to the number of samples N denoted by t, - h, and when the counter content j is smaller than the number of samples N, the process moves to step S16, and the number of variances n is set to Set the counter content j at .

In step S17, the indicated mean effective pressure P1j, which is the average value of the pressure within the combustion chamber 3 during one cycle, is determined based on the output of the pressure sensor 13. In step S18, processing is performed to perform the function of a comparison means for comparing the average value of the sensor output value and the sensor output at that time, and 1. Then, the degree of dispersion Aj corresponding to the comparison value is calculated using the following first equation.

However, 1) ij in J3 in the above first equation is the indicated mean effective pressure mentioned above. In the performance at step S18, when the counter content j is smaller than the number of samples N, the degree of dispersion n is set to the counter content j, and the one time degree Aj for cumulative calculation is simply calculated. Further, in step 818, when the counter content j is greater than or equal to the number of samples N, the number of variances n is set to the latest number of samples N in step S15, and the degree of variance Aj is 9 according to the first equation. For example, if the number of samples N is 5 and the counter content j is 6, the degree of dispersion Aj from the second to the sixth ripple detection times is calculated.

In step 81g, it is determined whether the degree of dispersion Aj determined by the slap Sm is greater than a predetermined value ε3, and when the degree of dispersion jIfi is greater than the predetermined value ε3, the process moves to step 32G, and if the counter content j is greater than or equal to the number of samples N, Determine whether it exists or not. When the counter content j is greater than or equal to the number of samples N, the process moves to step 821 to control the combustion state by correcting the fuel injection according to (+ri) of the dispersion degree Aj, and calculates the fuel injection change hiΔQf1 as a function of the dispersion degree Δj. This fuel injection changed ΔQf1 is set in step S22.
1) is added to the fuel injection ff1Qf of ifll, and the process moves to the next step S8, where this added fuel injection j
Twisting material injection is performed at i Q f.

On the other hand, in step 32G, when the counter content j is smaller than the number of samples NJ:, the process moves to step 323, and the fuel injection variation amount ΔQf1 is set to a constant value of 1IflC2.

Fuel injection change amount ΔQ'f set to this constant value C2
'1 is the previous fuel injection F in step S22.
It is added to lIQf, and the process moves to step S8, where fuel injection is performed using this added fuel injection ff1Qf.

According to this embodiment, a plurality of pieces of information regarding the combustion state are collected, and the stability of the engine is determined from the degree of dispersion of the information. In other words, the engine operating condition is stable in the high rotation and high load region or in the region where the fuel injection ratio is rich, so even if the number number N is relatively small, a reliable average value can be obtained, and the standard The combustion state of the engine can be determined quickly with a small amount of the above information, and since the engine operating state is unstable in the low rotation and low load region and the lean fuel injection amount region,
Accurate judgment can be made using much of the above information.

FIG. 3 shows lll1II of an engine according to an embodiment of the present invention.
This is a flowchart 1- for explaining the operation of other parts of the Il device.

In step rl 1, the ignition switch is turned on, and in step n2, the content N in the memory area of the learning map that stores the learning value of the counter content for each operating region of the memory 22 is set to "NO", and the content of the counter in the CPU 21 is set to "NO". ” to “0” respectively Jru1, Step n3
Now, the rotation speed is 12. /JS et al. engine speed rp+++ and booth h P from pressure sensor υ13
receive b. In step ``)4, the rotation speed rDII is
The fuel injection amount Ql' is calculated based on J3 and boost Pb, and in step 5, the content N of the storage area corresponding to the current driving state is read from the learning map.

In step n6, in order to detect whether the engine 1 is in a steady operating state or a transient operating state, it is determined whether the rotational speed change Δ "p" is smaller than a predetermined value ε1, and the rotational speed change When Δrpl is greater than or equal to the predetermined value 81, step n
7, the counter content j is set to [01, and further, in step n8, the fuel injection 1) IMQf is adjusted by a predetermined fuel injection change amount ΔQf'. Next, the process moves to step n9, and fuel injection is performed using this increased fuel injection MQf.

When the engine 1 is in a transient operating state as described above, the fuel is clarified in step n8, and the process returns from step n9 to step n3, whereupon the processes of slaps n3, n4, and n6 are performed. Here, in order to again judge whether the operating state of the engine 1 is in a transient operating state or in a steady operating state, step nθ is performed.

Perform niG processing. That is, when it is determined in step n8 that the rotational speed change Δrpl is smaller than the predetermined value ε1, and in step n1o that the intake It change amount ΔPb is smaller than the predetermined value ε2, it is determined that the engine 1 is in a steady operating state. To detect. Further, when the change in intake pressure btΔpb is equal to or greater than the predetermined value 82 at J3 in Stella 7n10, the process moves to Step N7 and the above-described processing is performed.

When the engine 1 enters a steady operating state, the process moves from step nlo to Stella 7n11, and the counter content, j, is incremented. In step 112, it is determined whether the counter content j is greater than or equal to the learning map content N. If the counter content j is greater than or equal to the learning map content N, the process moves to step n13, where the number of variances n is set to the learning map content N. , On the other hand, when the counter content jtfi is smaller than the learning map content N, the process moves to step n%, and the variance number n is set as the counter content j1.:.

In step n15, the indicated mean effective pressure Pij is calculated. In step ntII, when the counter content j is smaller than the school gate map content N, the variance number n is equal to this counter content j
is set, and the degree of dispersion Aj for j times is calculated by the first equation simply for cumulative calculation.

Further, in step n16, when the counter content j is greater than or equal to the learning map content N, the number of variances n is set to the latest learning map content N in step n13, and the degree of variance Aj is calculated by the first equation in #i. .

In step n17, in order to detect whether or not learning has been performed, it is determined whether the learning map content N read out from the learning map in step n5 is the initial value No. That is, when the learning map content N is the initial value N11, step n18. Moving on to n19, the amount of change in dispersion (Δ・−A
・-+), (A, -Aj-2), J J
It is determined whether J is smaller than a predetermined value ε4. In other words, dispersion degree change camellia (Δ3
Since both A j -1) and (A, -+-A-2) are smaller than the predetermined value ε4, which means that the number of zumblings is sufficient, move to Stella/'n2[1. , the counter content j is written as the learning map content N in a predetermined storage area of the learning map, and then the process moves to step n21.

The appropriate number of samples (period for calculating the average) according to the operating condition is determined by learning.

On the other hand, if step nv is a3 and 8N in the learning map is not the initial value No, it means that the learning has already been done, so step n?
Proceed directly to step 1.

In step n21, the degree of dispersion Aj is set to a predetermined value ε3 in order to detect whether or not the combustion state is in a region where the fluctuations in the combustion state are large.
If the degree of dispersion Aj is less than or equal to the predetermined value ε3, the combustion state is in a region where fluctuations in the combustion state are small (steady operating state). Perform fuel injection at step n.
In 21, when the variance is larger than the predetermined value ε3, the fluctuation of the combustion state is large (transient operating state).
Therefore, the process moves to step n22. step n 2
In step 2, it is determined whether the counter content j is greater than or equal to the learning map WN, and if the counter content j is greater than or equal to the learning map content N, fuel injection (71
To set ffiQr, move to step n23,
The fuel injection change amount ΔQf1 is exclusively used as the III number of the degree of dispersion Aj. This calculated fuel injection change MΔQf1 is
In step n24, the fuel injection amount QiJ is added to the previous fuel injection flQf, and then the process moves to step n9, where fuel injection is performed using the added fuel injection amount QiJ flQf.

On the other hand, in step n22, when the counter content j is smaller than the learning map content N, fuel injection is performed with a predetermined increase in fuel injection OA. Moving to n25, the fuel injection change amount ΔQf1 is set to constant 02. The fuel injection MC2 set to this constant C2 is performed at step n 2
4 is added to the fuel injection ff1Qf, and step n
At step 9, the acceleration is increased by the added fuel injection amount Of.

Although the indicated mean effective pressure is calculated in step Sv and step n15 in the above two embodiments, the time integral value of the pressure value may be used to shorten the calculation time.

(Effects of the Invention) As described above, according to the present invention, the combustion state is controlled based on the comparison between the average value of the sensor output during steady operation and the sensor output value during actual operation, and the Since the period for determining the value changes depending on the operating condition, it is possible to sample operating information for a minimum of 11 periods for each operating condition, which reduces the time required to determine whether the engine operating condition is stable. It is possible to control the engine with good viscosity because it is kept to the necessary minimum.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an engine control device according to an embodiment of the present invention, and FIG. 2 is a diagram of a first embodiment of the above-mentioned control device]!
II! Flowchart for explaining eh work, Part 3
The figure is a flowchart for explaining the processing operation of the second embodiment of the above-mentioned 1III all device. 1... Engine, 13... Pressure sensor, 20...
Control unit (including comparison means, combustion state υ control means, and changing means).

Claims (1)

[Claims] 1. In an engine control device that has a sensor that directly detects the combustion state and controls the combustion state according to the sensor output, the average value of the sensor output during steady operation is compared with the sensor output value during actual operation. A combustion state control means for controlling the combustion state of the engine based on the output of the comparison means, and a changing means for changing the period for determining the average value according to the operating state. Engine control device.