JP2835672B2 - Surge and torque detector for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a surge torque generation level in an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, during warm-up operation of an internal combustion engine, the engine temperature is low, so that the flow rate of the fuel flowing on the inner wall of the intake passage increases due to the low temperature. Since the fuel sometimes adheres and is difficult to mix with the air, the water temperature is increased according to the engine cooling water temperature in order to secure the amount of fuel in the air-fuel mixture.

Incidentally, the conventional water temperature increase correction K _TW is set in consideration of the above points, and is basically set to an amount necessary for not deteriorating the combustion. Of the total water temperature increase correction for the minimum required amount (specifically, approximately 25% of the correction for the former) + 5%
(The latter correction) = A rich mixture of about 30% is supplied.

[0004]

Therefore, when a high-quality fuel having good vaporizability is used and the variation in the parts of the fuel system is at a normal level, an rich mixture is supplied.
This resulted in worse fuel efficiency and emissions. The present invention has been made in view of the fact that such a conventional problem can be solved by setting the fuel increase so as to suppress the generation level of the surge torque to a predetermined level or less. It is an object of the present invention to provide a surge torque detecting device that can be used.

[0005]

Accordingly, a surge torque detecting device for an internal combustion engine according to the present invention, as shown in FIG. 1, detects a fluctuation state of a combustion pressure during a combustion stroke for a predetermined cylinder. Pressure fluctuation detection means, combustion pressure fluctuation detection means for detecting fluctuations in combustion pressure among a plurality of cylinders , and a low engine speed range based on the detection results of the combustion pressure fluctuation detection means and combustion pressure fluctuation detection means. Then,
Increase the weight of the detection result of the combustion pressure variation detection means.
In the high rotation range, the detection result of the combustion pressure
Surge torque detecting means for detecting the generation level of the surge torque by increasing the weight .

[0006]

In a high-speed region of the engine which is detected by the operating state detecting means , the surge torque is greatly affected by fluctuations in each rotation of the same cylinder, and is also detected by the operating state detecting means. In the low engine speed region, the generation of surge torque is more affected by the variation in combustion pressure among a plurality of cylinders. Therefore,
The surge torque detecting means is provided in the low engine speed range of the engine based on the combustion pressure fluctuation state of the same cylinder detected by the combustion pressure fluctuation detecting means and the combustion fluctuation between the cylinders detected by the combustion pressure fluctuation detecting means. Combustion pressure variation
Increase the weight of the detection result of the detection
The combustion pressure level is detected at high engine speeds.
Increase the weight of the detection result of the
Detects the generation level of battery torque.

Therefore, the surge torque detecting means converts at least one of the combustion pressure fluctuation state of the same cylinder detected by the combustion pressure fluctuation detecting means and the combustion fluctuation between the cylinders detected by the combustion pressure fluctuation detecting means. Based on this, the occurrence of surge torque is detected satisfactorily over the entire operation range.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2 showing the configuration of the first embodiment, air is sucked into the internal combustion engine 1 through an air cleaner 2, an intake duct 3, a throttle chamber 4, and an intake manifold 5.

The intake duct 3 is provided with an air flow meter 6 for detecting an intake air flow rate Q. The throttle chamber 4 is provided with a throttle valve 7 interlocked with an accelerator pedal (not shown) to control the intake air flow rate Q. The intake manifold 5 is provided with an electromagnetic fuel injection valve 8 as a fuel injection means for each cylinder, and injects and supplies fuel which is fed from a fuel pump (not shown) and controlled to a predetermined pressure by a pressure regulator.

Also, the crank angle phase difference of each cylinder of the engine (
For example, in the case of a four-cylinder engine, a crank angle sensor 9 that outputs a reference signal REF every 180 °, a water temperature sensor 11 that detects the temperature of cooling water of the engine, and a combustion engine of each cylinder that is fastened together with, for example, an ignition plug. A combustion pressure sensor 10 for detecting pressure (in-cylinder pressure) is provided, and a detection signal from these is output to a control unit 12 built in the microcomputer, and the control unit 12 generates a surge based on these detection signals as follows.・ Detect the torque and set the fuel water temperature increase correction coefficient K _TW .

A routine for setting the water temperature increase correction coefficient K _TW by detecting surge torque will be described below with reference to FIG. Step (S in the figure; the same applies hereinafter) In step 1, an analog value of the combustion pressure detected by the combustion pressure sensor 11 mounted on the cylinder in the combustion stroke every predetermined minute unit time (for example, 12.8 μs) To a digital value.

In step 2, based on the detection signal from the crank angle sensor 9, it is determined whether or not the cylinder is within a predetermined crank angle range in the combustion stroke. And
If it is determined that the predetermined crank angle range, the converted sample values in step 1 proceeds to step 3, is stored as M _i in the memory M. In step 4,
Sum of the difference between the M _i and the previous _{M 1-i Σ (M i} -M
_1-i ) = ΔM is calculated.

In step 5, the ΔM obtained in step 4 is Fourier-transformed. As a result, the level of each frequency component whose sampling cycle is a unit cycle and each cycle is 1 to i times the cycle is obtained. In step 6, and stored in the memory A by selecting the level [Delta] P ₁ of predetermined frequency component f _n involved in the surge torque from the result of the Fourier transform. In this case, only one frequency component that is most involved in surge torque may be selected, or a plurality of frequency components may be selected and stored simply or weighted and averaged. .

The steps 1 to 6 correspond to combustion pressure fluctuation detecting means for detecting a combustion pressure fluctuation for each rotation of a predetermined cylinder. Next, in step 7, reads the detection values M _i1 ~M _in the combustion pressure at the same crank angle timing of the same stroke each for each cylinder 1 to n. In step 8, obtained for between all cylinders difference (variation) .DELTA.M _i of the combustion pressure M _i1 ~M _in between the cylinders, and adds all these. As a result, the maximum variation in the combustion pressure between the cylinders is detected.

In step 9, Fourier transform ΔM _i for all i in the predetermined crank angle range. In step 10, the level of a predetermined frequency component related to the surge torque is selected and stored in the memory B. In step 11, it is stored in the memory B to select the level [Delta] P ₂ of a predetermined frequency component f _m involved in the surge torque from the result of the Fourier transform. Also in this case, a value obtained by averaging the values of a plurality of frequency components simply or by adding weights may be stored.

Steps 7 to 11 described above correspond to combustion pressure variation detecting means for detecting variation in combustion pressure between cylinders. In this manner, after detecting the variation in the combustion pressure in the same cylinder and the variation in the combustion pressure between the cylinders, the water temperature increase correction coefficient K corresponding to the surge torque generation level is comprehensively taken into account. _{Make TW} correction settings.

In this embodiment, since the generation level of the surge torque is unknown at the start of the warm-up, the water temperature increase correction coefficient K _TW is set to a high value as in the conventional case, and the surge torque While detecting the occurrence level, the water temperature increase correction coefficient K _TW is gradually reduced, and the reduction amount Δ
K _TW is set based on the detection of the variation in combustion pressure in the same cylinder and the variation in combustion pressure between cylinders.

That is, based on the combustion pressure fluctuation ΔP ₁ in the same cylinder stored in the memory A and the combustion pressure variation ΔP ₂ between the cylinders stored in the memory B, a decrease corresponding to the surge torque generation level. The amount ΔK _TW is stored in the ROM in advance Δ
Reduction amount Δ stored with P ₁ and ΔP ₂ as parameters
_Calculated from K _TW . Here, in the low engine speed region, ΔP ₁ is more involved in the generation of surge torque,
In the high rotation region, ΔP ₂ is more involved in the generation of surge torque, so if one of them is large, or if the total value of both is more than a certain level, the generation level of surge torque is assumed to be large and ΔK _TW Is set small. Therefore, this step 11 is configured to include the surge torque detecting means.

In step 12, the water temperature correction increase coefficient K _TW is corrected and updated by subtracting the decrease amount ΔK _TW obtained as described above from the current water temperature correction increase coefficient K _TW . With this configuration, the generation level of the surge torque can be detected satisfactorily over the entire region of the engine, and the fuel water temperature increase correction can be appropriately performed in accordance with the detected level. It is possible to prevent deterioration of fuel efficiency and exhaust emission due to the increase correction.

Also, in step 2, outside the predetermined crank angle range
Is determined, ΔP_1,ΔP _TwoUpdate
No, step 11_,Proceed to 12. Next, the combustion pressure between cylinders
Another embodiment for detecting the variation will be described. Same
Regarding the detection of the combustion pressure fluctuation of the cylinder, the step shown in FIG.
Steps 1 to 6 are the same as steps 7 to
Step 10 replaces steps 21 to 23 in FIG.
Can be

That is, it is actually difficult to directly detect the variation in the combustion pressure between the cylinders that occurs in the high-speed region as in the above-described embodiment, and it is easy to generate a large calculation error. Further, it is necessary to provide the combustion pressure sensor 11 for each cylinder, which increases the cost. Although it is possible to provide only one and sample during a predetermined crank period of each cylinder, since the levels of cylinders far from the sensor are different,
Poor in accuracy. Therefore, the combustion pressure sensor 11 is provided only for one specific cylinder, and the variation of the combustion pressure between the cylinders is detected by the fluctuation of the rotation speed having the cycle of the crank angle phase difference of each cylinder. Here, since a reference signal is generated by the crank angle sensor 9 for each crank angle phase difference of each cylinder, the fluctuation of the rotation speed is obtained every time the reference signal REF is input.

Referring to FIG. 4, at step 21
Is the reciprocal of the input cycle of the reference signal REF for each input
Rotation speed N as a value proportional to_iAsk for. Step 22
Then, the rotation speed N obtained in the same way_i-1And the difference
Sum Σ (N _i-N_1-i) = ΔN is calculated. Step 23
Then, Fourier transform the ΔN obtained in step 4 above.
You. Thereby, the cycle of the reference signal REF is defined as a unit cycle.
Then, for each frequency component whose period is 1 to i times the period,
Level is required.

In step 24, the level ΔP ₂ of a predetermined frequency component (a plurality of frequency components may be averaged) related to the surge torque is selected from the result of the Fourier transform and stored in the memory B.

[0024]

As described above, according to the present invention, the generation level of surge torque can be detected with high accuracy over the entire operation range, and the fuel level can be determined based on the detected surge torque value. By setting the water temperature increase correction coefficient appropriately, it is possible to improve fuel efficiency _, exhaust emission and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration and functions of the present invention.

FIG. 2 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 3 is a flowchart showing a routine for detecting surge torque and correcting a water temperature increase correction coefficient based on the detection according to the embodiment;

FIG. 4 is a flowchart showing a routine for obtaining a combustion pressure variation between cylinders according to a second embodiment of the present invention;

[Explanation of symbols]

 1 internal combustion engine 9 crank angle sensor 10 combustion pressure sensor 12 control unit

Continuation of the front page (56) References JP-A-59-46352 (JP, A) JP-A-2-78749 (JP, A) JP-A-59-52726 (JP, A) JP-A-60-337 (JP) , A) JP-A-60-1356 (JP, A) JP-A-60-187739 (JP, A) JP-A-63-140848 (JP, A) JP-A-63-246440 (JP, A) JP-A-2-290946 (JP, A) JP-A-2-75742 (JP, A) JP-A-2-75743 (JP, A) JP-A-3-18652 (JP, A) JP-A-4-101044 (JP, A A) JP-A-4-214946 (JP, A) JP-A-4-214947 (JP, A) JP-A-4-299084 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) ) F02D 41/00-45/00

Claims (1)

(57) [Claims] 1. A combustion pressure fluctuation detecting means for detecting a fluctuation state of a combustion pressure during a combustion stroke for a predetermined cylinder; a combustion pressure fluctuation detecting means for detecting a fluctuation of a combustion pressure among a plurality of cylinders; Based on the detection results of the fluctuation detecting means and the combustion pressure variation detecting means , and in a low engine speed range of the engine.
Now, weighting of the detection result of the combustion pressure variation detection means
And the detection result of the combustion pressure detecting means in a high rotation range.
A surge torque detecting device for an internal combustion engine, comprising: surge torque detecting means for detecting the level of occurrence of surge torque by increasing the weight of .