JPH01130057A - Ignition timing controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To control ignition timing in a highly accurate manner by determining an ignition timing compensation value from each deviation value of two crank angles when the same cylinder internal pressure is generated by holding maximum cylinder internal pressure at each cylinder in between and a specified target crank angle deviation value. CONSTITUTION:A deviation value theta between respective crank angles thetai, thetae when a cylinder internal pressure peak position is held in between at each cylinder and the same cylinder internal pressure is generated in front and in the rear is calculated by a crank angle deviation value calculating means 21. In addition, a target crank angle deviation value theta' is read by a target crank angle deviation value setting means 22. Then, when theta is larger than theta', a timing advance value alpha deg. is set, and conversely, when theta is smaller than theta', a timing delay value beta deg. is set by an ignition timing compensating means 23. At an ignition timing setting means 24, fundamental ignition timing is retrieved, and the ignition timing compensation value alpha deg. or beta deg. is added, setting the actual ignition timing, and it is independently outputted to an ignition coil 21 at each cylinder. According to this constitution, since reliability in the cylinder internal pressure measured is high, the ignition timing is controllable in a highly accurate manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition timing control device for an internal combustion engine that measures in-cylinder pressure for each cylinder and determines optimal ignition timing for each cylinder accordingly.

[Prior art and problems to be solved by the invention] Conventionally, the ignition timing has been controlled in each operating range so as to be close to the minimum ignition advance angle (MBT) at which the maximum torque can be obtained within the knock limit. It is known that if you do so, you can maximize the engine's fluidity.

This type of ignition timing control device d has been devised and adopted in various ways in the past. For example, Japanese Patent Laid-Open No. 62-554.61 discloses a method for controlling the cylinder pressure (combustion pressure) that can produce the maximum torque.
A technology has been disclosed that controls the ignition timing by measuring the in-cylinder pressure values at two symmetrical crank angle positions with an in-cylinder pressure sensor centered around the crank angle position where the peak occurs, and by adjusting the difference between them to be "O". has been done.

This means that the cylinder pressure is symmetrical to the left in a small angular range around its peak position, that is, in the range of crank angle positions -8° to +8°, and therefore, the ignition timing is
We focused on the fact that when the peak position of the cylinder pressure is controlled to be at the optimum crank angle position, the difference in the cylinder pressure between the crank angle positions that are symmetrical with the peak position becomes ``0''. It is something.

By the way, when knocking occurs due to air-fuel ratio changes, disturbances, or other influences, the in-cylinder pressure waveform of the in-cylinder pressure measured by the above-mentioned in-cylinder pressure sensor is disturbed, which becomes a source of erroneous measurements. In other words, knocking tends to occur after the compression top dead center (ΔTDC), as shown in the cylinder pressure waveform B in FIG.

Therefore, as in the prior art described above, the in-cylinder pressure is measured at crank angle positions that are slightly angularly biased from the peak position of the in-cylinder pressure to the left, right, left, and first positions, and the ignition timing is controlled based on this. In this case, the in-cylinder pressure value fluctuates due to the influence of knocking, making it impossible to obtain the true pressure value associated with combustion.

As a result, there is a problem that not only does pressure measurement become unreliable, but also interferes with accurate ignition timing i1i+ control.

[Object of the Invention] The present invention has been made in view of the above circumstances, and provides an internal combustion engine that can measure the in-cylinder pressure value without being affected by knocking and can accurately control the ignition timing. The company's 11th standard is to provide ignition timing control devices.

[Means and effects for solving the problem] The ignition timing control device for an internal combustion engine according to the present invention includes a control means for updating the ignition timing according to an output signal from a cylinder pressure sensor provided in each cylinder. a crank angle deviation calculation means for calculating the deviation between two crank angles at which equal cylinder pressures occur before and after the internal pressure; and a target crank for setting a target value of the crank angle deviation predetermined according to the operating state. an angular deviation amount setting means, an ignition timing correction means for comparing the crank angle deviation m and the target crank angle deviation amount, and setting an ignition timing correction amount in accordance with the comparison value; An ignition timing setting means is provided for calculating the actual ignition timing from the set basic ignition timing and the correction amount of the ignition timing correction means.

In other words, the cylinder pressure angle of 11 nicles is monitored for each cylinder, and in each cylinder, the cylinder pressure at a preset crank angle is detected, and then the maximum cylinder pressure is narrowed down to the same level. Detects the crank angle when cylinder pressure occurs. Therefore, calculate the deviation of the above two crank angles,
This amount of deviation is compared with a target value of the amount of deviation previously set according to the operating state, and the correction ω of the ignition timing is determined based on the comparison result.

[Embodiments of the invention] Hereinafter, the present invention will be described in detail with reference to the drawings.

The drawings show one embodiment of the present invention; FIG. 1 is a schematic plan view of the main parts of the engine, FIG. 2 is a schematic side view of the engine, FIG. 3 is a block diagram of the control means, and FIG. 4 is a diagram of the control means. The flowchart, FIG. 5, is a cylinder pressure waveform diagram in which the vertical axis represents the cylinder pressure (P) and the horizontal axis represents the crank angle (θ).

Reference numeral 1 in the figure is a four-cylinder horizontally opposed engine body, which is an example of a multi-cylinder internal combustion engine, and the cylinder block 2
is on both sides (LH, RH
) is divided into two banks.

Each piston 4 fitted into the 8-air fFi 12a, 2b, 2C, and 2d provided in the L+-1 bank and the RH bank of the cylinder block 2 is connected to the crankshaft 3 via a connecting rod (not shown). connected. Further, a combustion chamber 6 is provided in a portion surrounded by the piston 4 and cylinder heads 5a and 5b of each of the cylinders 2a to 2d.
a, 6b, 5c, and 6d are formed, respectively.

Further, an in-cylinder pressure sensor 7 is attached and fixed to each of the cylinder heads 5a, 5b via an adapter 8, and a tip detection portion of this in-cylinder pressure sensor 7 faces each of the combustion chambers 6a to 6d. Furthermore, each of the above cylinder heads 5a
, 5b are equipped with spark plugs 9 corresponding to the respective cylinders 2a to 2d. Note that the cylinder pressure sensor 7 may be directly fixed to the cylinder heads 5a, 5b.

Further, an injector 1 is installed near the intake valve (not shown) of the intake manifold 11 that communicates with the combustion chambers 6a to 6d.
0 is coming. Furthermore, this intake manifold 11
A throttle chamber 14 in which a throttle valve 13 is interposed is communicated with the upstream side of the throttle valve 13 . Further, the upstream side of this vacuum chamber 14 is communicated with an air cleaner 17 via an intake pipe 15 and a main passage 16a of a hot wire air flow meter 16, which is an example of an intake air amount sensor (see FIG. 2).

The air flow meter 16 also includes the main passage 16.
A sub-passage 16b is provided which bypasses the wire a, and a part of the bridge circuit provided in the controller 16c is connected to the sub-passage 16b through which a hot wire 16d and a temperature compensation wire 16e are connected. This air flow meter 16 measures the quality of the intake air flowing through the sub passage 16b, that is, the intake air htQ, and the controller 1
The measurement signal is output from 6G.

In addition, the crankshaft 3 has an engine speed N
and a crank angle sensor 1 that detects the crank angle Crθ.
8 are arranged in a row. Note that reference numeral 19 is a throttle sensor that detects the throttle opening.

On the other hand, reference numeral 20 is a control means, and this control means 2.O
The above-mentioned sensors 7, 16, 18 are connected to the input side of the engine, and the above-mentioned injectors 10 are connected to the output side of the engine, and the ignition plugs 9 are connected to each other via independent ignition coils 21. There is.

Further, the control means 20 is provided with a crank angle deviation amount calculation means 21, a target crank angle deviation amount setting means 22, an ignition timing correction means 23, an ignition timing setting means 24, and a driving means 25.

The crank color width difference fl output means 21 uses the engine rotational speed signal N of the crank angle sensor 18 and the crank angle signal Crθ to determine a preset crank angle θi before the in-cylinder pressure peak position for each cylinder 6a to 6d. The cylinder pressure Pi at this time is detected from the output signal of the cylinder pressure sensor 7.

Then, after the cylinder pressure peak position n, the same pressure value as the cylinder pressure Pi detected at the crank angle O1 is detected again at a crank angle of 1σθe, and both of these rank angles θi, 0
Sign out the crank color width ZOΔ0 between 0 and η.

In addition, in the target crank color width difference setting stage 1 stage 22, the corresponding area of the map is searched from the engine rotation speed signal N and the intake air M signal Q of the air flow meter 16, and the target crank color width set there is searched. Read the angular deviation amount Δ08. This [] mark crank angle color width difference Δθ1 has been determined in advance through experiments for each operating range, and is based on a three-dimensional map (crank angle deviation amount map) composed of engine speed N and intake air IQ. ) is written in.

By the way, there is a correlation between the crank angle deviation amount AO and the ignition timing, and when the crank color deviation hΔθ becomes larger than the optimum V1 (target value), the ignition timing becomes the value at which the output torque is maximum (MBT
) will shift toward the advanced side, and conversely, if it becomes smaller, it will shift toward the even angle side.

A in FIG. 5 is the target crank angle deviation amount Δθ” (=θeA−θi
), which was determined based on the minimum ignition advance angle (MBT) that provides a maximum of 1 to 1.

Further, B is the in-cylinder pressure waveform when the angle is advanced from the above-mentioned MBT, and knocking is likely to occur after the in-cylinder pressure peak (P peak). Furthermore, C is the in-cylinder pressure waveform when the angle is retarded from the above-mentioned MBT.

As you can see from this diagram, the crank angle deviation! i'+, 4
1jθ increases as the amount of retardation increases. Therefore, the crank angle θi needs to be set at a position that avoids fluctuations in the cylinder pressure due to the knot V-ring.

Further, the ignition timing correction means 23 calculates the crank angle deviation amount -〇 calculated by the crank angle deviation amount calculation means 21,
The target crank angle deviation determined by the target crank angle deviation amount setting means 22'C is also compared with 1Δθ9 to calculate the ignition timing correction amount.

That is, the crank angle deviation 3dΔ0 is the target value Δθ*J:
If the value is larger than the target value Δθ1, the ignition timing advance amount α° is set, and conversely, if it is smaller than the target value Δθ1, the retardation amount β° is set.

In addition, the ignition timing setting means 2/'I sets the corresponding Lt main ignition timing from the basic flaming map set for each operating region based on the engine speed N and intake air IQ. IJo is searched.Then, this basic ignition timing Igo is determined by the advance or retard compensation i1- (from 3M at the actual ignition time II
grcal is set, and the corresponding area of the ignition timing map is rewritten with the value of this ignition timing 1greal.

This ignition timing is 1grca+ (1st is the drive circuit 4 above)
5, the spark plug 9 is independently output to the ignition coil 21 provided corresponding to each cylinder, and the spark plug 9 is connected to each cylinder 6a.
- Spark independently depending on the state of 6d.

Here, the crank color width; r suspension Δθ varies with changes in the operating range determined according to the engine speed N and the intake air condition Q, and its target value Δθ1 is determined by experiment etc. to the maximum torque (MBT). (set directly) such that 1q is reduced.

Further, the ignition timing map is provided corresponding to each cylinder, and the ignition timing of each cylinder is independently controlled.

Next, the control procedure of the control means 20 will be explained according to the flowchart shown in FIG.

First, in step 101, the cylinder pressure is measured. Then,
In step 102, the cylinder pressure P1 at a preset crank angle θi before the cylinder pressure peak (P peak) position is detected, and this cylinder pressure Pi is stored.

Then, in step 103, the cylinder pressure peak (Ppeak
) position, the cylinder pressure shows Pi again and J crank angle θe
Detect. The crank angle θi is set at a position where pressure fluctuations due to knocking do not affect the in-cylinder pressure value at the crank angle θC.

Then, in step 104, the crank color width of the crank angles θi and θe of the in-cylinder pressure peak surface; 2 H'r aθ
Calculate. In step 105, it is determined whether the rank color width j', -KL I O is larger than the [1 standard crank angle deviation n11Δθ9] corresponding to the operating region determined based on the engine speed N and the intake air IQ. If it is large, the process moves to step 106 and the ignition timing in the current operating range is advanced by α°CA.

On the other hand, when it is determined that it is not large, it is determined in step 107 whether the crank color width difference Δθ is smaller than the target crank color width difference 40′, and if it is smaller, step 10
Proceed to step 8 and set the ignition timing by β°CΔd.

Also, if it is not small, ・) That is, crank color width; 2
If fljΔθ and the target crank color width difference Δθ1 are equal, the process ends.

Then, in step 109, the value in the corresponding region of the ignition timing map is updated with the value newly set by advancing or retarding the ignition timing in the current operating region in steps 106 and 108.

Note that the present invention is not limited to the above-mentioned embodiments, and for example, the crank angle deviation amount Δθ and the target crank color width difference Δθ9 may be obtained from the crank angle that has been measured based on a preset cylinder pressure. Good too.

[Effects of the Invention] As explained above, according to the present invention, the ignition timing is controlled by measuring the cylinder pressure outside the crank angle range in which knocking does not occur, that is, the cylinder pressure waveform is affected. The reliability of the measured cylinder pressure value is high, and the ignition timing can be adjusted to 11 degrees.

In addition, variations in dimensions for each cylinder due to wA construction, etc.
The ignition timing for each cylinder can be set to the maximum value without being affected by differences in intake air a and fuel supply amount, and superior effects such as improved fuel efficiency and output can be achieved.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a schematic plan view of the main parts of the engine, Fig. 2 is a schematic side view of the engine, Fig. 3 is a block diagram of the control means, and Fig. 4 is a control unit. FIG. 5 is a flowchart of the means; FIG. 5 is a cylinder pressure waveform diagram in which the vertical axis shows the cylinder pressure (P) and the horizontal axis shows the crank angle (θ). 2a to 2d...Cylinder, 7...Cylinder pressure sensor, 20.
... Control means, 21... Crank corner difference suspension calculation means,
Target crank color width difference setting means, 23... Ignition timing correction means, 24... Ignition timing setting means, θi, θe...
・Crank angle, Δθ...Crank angle deviation is Δθ9・
...Target crank angle deviation amount, P...(cylinder pressure sensor output signal, p peak...maximum cylinder pressure. Fig. 4 G6D)

Claims (1)

[Claims] The control means for updating the ignition timing according to the output signal of the cylinder pressure sensor provided in each cylinder calculates the amount of deviation between two crank angles at which equal cylinder pressures occur around the maximum cylinder pressure. a crank angle deviation amount calculation means for calculating a crank angle deviation amount, a target crank angle deviation amount setting means for setting a target value of the crank angle deviation amount that is predetermined according to the operating state, and a crank angle deviation amount calculation means for setting a target value of the crank angle deviation amount that is predetermined according to the operating condition; ignition timing correction means that compares the ignition timing with the ignition timing correction amount and sets the correction amount of the ignition timing according to the comparison value; An ignition timing control device for an internal combustion engine, comprising ignition timing setting means for calculating ignition timing.