JPS61201863A - Method for fuel injection quantity control of diesel engine - Google Patents

Abstract

PURPOSE:To always optimum dush pot control by correcting dush pot volume in accordance with the state of load from engine accessory. CONSTITUTION:When engine rotation speed Ne is judged to have become smaller than judgement rotation speed Nj at step 100, counter CQR is reduced by one count at step 104, and when counter CQR is judged to be zero at step 106, initial value 1.0 is set to load coefficient KQR of engine accessory at step 110. When load no power steering and alternator is judged to be big at steps 112 and 116, load coefficient KQR is added to by 0.1 at steps 114 and 118. Decline volume ND is calculated by deducting engine rotation speed Ne from judgement rotation speed Nj at step 120. Dush pot volume QREC adjusted in consideration of load coefficient KQR is obtaindd from decline volume ND at step 122 and then reflected in injection quantity as pseudo accelerator divergence.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fuel injection amount control method for a diesel engine, and in particular, to prevent engine stall or significant irregular rotation when the engine rotational performance falls below a predetermined determined rotational performance. This invention relates to an improvement in the method of fuel injection 1)IilIII11 for a diesel engine, in which the amount of fuel injection in a diesel engine is increased by an amount of dashpot corresponding to the rate of decline by electronic control, and then gradually attenuated to zero.

[Conventional technology]

When the engine suddenly shifts from a steady or accelerating state to a decelerating state, ignition errors are likely to occur due to sudden changes in the combustion state, resulting in markedly irregular rotation, or in extreme cases, the engine may stop. In order to prevent these situations, conventionally, for example, as shown in FIG.
1) When the rotation speed decreases below NJ, the fuel injection 1) J I
Instead of immediately reducing t to zero, the so-called dashpot i! Q
A fuel injection amount control method is known in which the fuel injection amount is increased by REc. In diesel engines that control the dashpot amount electronically without using a mechanical mechanism, the dashpot amount QREC is generally calculated using the following formula, and this is used as a pseudo accelerator opening to control the injection ill. I'm trying to reflect that. QqEc = 8
This is the amount that is lower than j during the determination time Tj. In addition, this dashpot IQREC is suppressed to within 8% at maximum, and after being reflected in the song as a pseudo accelerator opening, it is attenuated at a rate of, for example, 8%/2.5sec. . Also, if the judgment rotational movement Nj is set to a too large value, f[, which makes the dashpot ineffective, will increase, so it is normally set to 12
It is said that it is preferable to set it to about 00≦Nj≦1600 (ROM). Problem to be Solved by the Invention 1 However, the conventional dashpot IQREC obtained in this way does not depend on the load state caused by the power steering or the supplementary examples of the engine such as the alternator. This calculation There was a problem that the dashpot IQRic that was created may not be appropriate. That is, as shown in FIG. 3, for example, if the power steering is a rotation speed sensitive type, the dash photo
After 7300 rDmtJ when I:c is calculated, the hydraulic load is not so high compared to 700 ram, which is the lowest idle speed, and the higher the engine speed, the higher the electromotive capacity for the alternator and ternator loads. Therefore, it doesn't get that big. t, t are the dashpot IQqEc calculated when calculating the dashbot IQqEc, even if the load from engine auxiliary equipment such as power steering and alternator is heavy, the drop in rotation is not that significant.
It doesn't get that big either. However, when the engine rotational speed decreases, the load from these auxiliary machines is added to the engine as a heavier load than when the engine was running at high speed, so the calculated dashpot IQF2EC is too small and may cause the engine to stop, etc. This may lead to an accident. [Objective of the Invention 1] The present invention has been made in view of the above-mentioned conventional problems, and is aimed at providing optimal dashpot control at all times, regardless of the load state of engine auxiliary equipment such as power steering and alternator. An object of the present invention is to provide a fuel injection amount control method for a diesel engine that can perform the following steps. (Means for Solving the Problem 1) The present invention lowers the fuel injection tJUI in order to prevent engine stall or significant irregular rotation when the engine rotational performance falls below a predetermined judgment rotational performance. The dashpot amount is increased by electronic control according to the speed, and
The above object is achieved by correcting the dashpot amount according to the engine load condition in mm in a diesel engine fuel 111 station control method in which the fuel is gradually attenuated to zero thereafter. Further, in an embodiment of the present invention, the load state of the auxiliary equipment is detected by at least one of the detection of oil pressure of the power steering and the detection of the field current of the alternator. The load state can be detected easily and accurately. Further, in another embodiment of the present invention, when there is a variation in the load condition while the dashpot amount is being attenuated, this variation is reflected in the damping characteristic.
For example, consideration must be given to prevent situations such as engine auxiliary equipment load from being calculated when the dashpot amount has not been increased, or engine stoppage even if these loads become large while the dashpot is damping. This is what I did. (Function) In the present invention, in view of the fact that the load condition by engine auxiliary equipment is not necessarily faithfully reflected in the amount of decrease in engine rotational performance, the dashpot amount calculated based on the amount of decrease is Since the correction is made directly according to the load condition of the auxiliary equipment, it is possible to increase the optimal dashpot amount of fuel regardless of these load conditions. [Example 1 The following is based on the drawings. An embodiment of the present invention will be described in detail. Fig. 1 shows a 10IS routine of an embodiment of the present invention. First, in step 100, it is determined whether the engine rotational performance Ne is smaller than the determined rotational performance Nj. If the engine rotational performance N,e is larger than the judgment rotational performance Nj, the process proceeds to step 102, where 1/10 of the judgment time T'' is set in the counter CQl?.This embodiment Since the judgment time Tj is set to 100 m5, the counter CQR is set to 10. Eventually, at step 100, the engine rotational speed N is calculated by 1.
When it is determined that e has become smaller than the determined rotational movement Nj, the process proceeds to step 104 and the empty 2900 days are
Then, the process proceeds to step 106. In step 106, it is determined whether the counter CQR has become zero. If it is determined that the amount has not reached zero, proceed to step 108 and set the dashpot amount QRE.
It is determined whether C has already been calculated and has risen,
If it has not risen, the flow is immediately terminated. When this flow is repeated 10 times every 1013, it is determined in step 106 that the counter CQ Rh<0, so the process proceeds to step 110, where initial mi and os are set to the load coefficient KQR of the engine auxiliary equipment. Next, in step 112, it is determined whether the load on the power steering P/S is large. This determination is made by detecting the oil pressure of the power steering P/S and determining whether or not the oil pressure exceeds a specific threshold value. If it is determined that the load on the power steering p, -'s is large, a load coefficient KQR of 0.1 is added in step 114. Similarly, in step 116 it is determined whether the load on alternator ALT is large, and if it is large, then in step 118 the load coefficient KQR is similarly set to 0.
Add only 1. Note that the determination as to whether the load on the alternator ALT is large is made by detecting the field 'R current of the alternator and determining whether or not the field current exceeds a specific threshold value. After the load coefficient KQR due to the engine auxiliary equipment is determined, in step 120, the determination rotational performance N
The decrease in I Nolfi is calculated by subtracting the engine rotational performance Ne from j. When a″FINo is calculated, in step 122, dashboards 1 to IQqEc are calculated in consideration of the load aKoR.
is calculated. This calculation is performed by multiplying the conventional and recovery formula of 8×N o / 400 by the load coefficient KQR using the decrease INo obtained in step 120, and this dashpot 1lQqEc is used as the pseudo accelerator opening to calculate the injection amount. reflected. Note that the dashpot amount QREC is set to KQRX8 (%) when No/400 is 1 or more. For the bond whose dashpot IQREc has been calculated, an initial value of zero is entered in the decay stop counter Co of the dashpot hllQqEC in step 124, and the flow ends. This routine is repeated every 10111S even if the flow ends in step 124. However, after the dashpot IQpEc is calculated, step 10
Since it is determined in step 8 that the dashbot acid Qq t: cffi is not zero, the attenuation logic from step 126 onwards is entered. First, in step 126, it is determined whether the load coefficient KQR is the maximum value 1.2. When it is determined that R is 1.2 in the p4 loading coefficient,
It is assumed that the dashpot IQRic has been sufficiently increased, and the dashpot IQREC determined in step 128 is attenuated at a rate of 8%/'2.58. That is, in this step 128, 0.032
% of the dashpot amount QRεC is performed. When it is determined in step 126 that KQR is not 1 or 2, the process proceeds to step 130, where the load coefficient KQ
It is determined whether R is 1.1. Loader @KQR
If it is determined that 1.1, it means that it was determined in step 112 or 116 described above that only one of the power steering P/S or the alternator ALT had a large load. Therefore, in this case, step 13 checks whether the load has increased since then.
If it is determined in step 2 that the amount has not increased, a predetermined attenuation is performed in step 128. If it is determined that the attenuation stop counter Co is increasing, in step 134, the attenuation stop counter Co becomes 30 or less, that is, 30013.
It is determined whether the decay stop counter C
If o is less than 30, the attenuation stop counter Co is incremented by 1 in step 136, and the flow is ended without attenuation. This damping stop continues until it is determined in step 132 that both the power steering P/S and the alternator ALT are not under heavy load, or until the damping stop counter Co exceeds 30 in step 134. On the other hand, in step 130: the load coefficient KQR is 1.
If it is determined that KQR is not 1, then KQR is 1°0, that is, the power steering P/
This means that it was determined that both S and alternator ALT had a small load. Therefore, in step 138, it is determined whether or not the load on either the power steering P/S or the alternator ALT has become large since then, and if the load has become large, the process proceeds to step 134, where the attenuation is stopped and the load has become large. If it is determined not to be the case, attenuation is performed in step 128, respectively. According to this embodiment, when calculating the dashpot amount QREC, the load condition of the engine auxiliary equipment is taken into consideration, so that the Dashbot III can perform its original function regardless of these conditions. can. In addition, when attenuating the calculated dashpot amount, changes in the load condition are monitored from time to time, and the attenuation is stopped accordingly. Even if the state changes, it can be dealt with appropriately. In addition, in the above embodiment, only the power steering P/S and the alternator ALT were considered as auxiliary machines that affect engine rotation, but the auxiliary machines in the present invention are not limited to these two. In short, it includes everything that acts as a resistance element to engine rotation, regardless of the driving condition. Therefore, in principle, this auxiliary equipment includes the compressor load of the air conditioner, but generally when the air conditioner is turned on, fuel injection 111tllll dedicated to idle up etc. is performed. I try to exclude it from Further, in the above embodiment, the dashpot lid QRεC
If the load condition becomes large while performing damping, the damping is stopped for a certain period of time to deal with this, but the control during damping in the present invention is limited to this. Instead, for example, when it is determined in step 126 that the load coefficient KQR is 1°2, and it is determined that both the power steering P/S and alternator ALT loads are light, the attenuation speed of the dashpot amount QREC is increased. Therefore, a means for preventing the engine rotation from rising due to the dashpot being too effective may be provided. Note that, in the present invention, control of the dashpot IQREC during attenuation is not necessarily required. [Effect of the Invention 1] As explained above, according to the present invention, the dashpot amount can be optimally set according to the load condition of the engine auxiliary equipment, so regardless of these conditions,
The excellent effect of being able to perform dashpot control more accurately can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an embodiment of the fuel injection amount control method for a diesel engine according to the present invention, and FIG. 2 is a diagram showing engine rotational operation and dashpot amount for explaining a conventional method for calculating the dashpot amount. FIG. 3 is a miniature diagram similar to FIG. 2 for explaining the problems of the conventional example. Ne...Engine speed, QREC...Dashpot amount, Nj...Judgment speed, Tj...Judgment time, NO...Decrease amount, P/S...Power steering ( engine auxiliary equipment), A
LT...Alternator (engine auxiliary equipment), KQR...
- Load coefficient, Co... damping stop counter.

Claims (3)

[Claims] (1) In order to prevent engine stall or significant irregular rotation when the engine rotational speed drops below a predetermined determined rotational speed, the amount of fuel injection is increased by the amount of the dump pot according to the speed of decline using electronic control. and then gradually attenuating the fuel injection amount to zero, the method comprising: correcting the dumppot amount according to a load condition of an auxiliary machine of the engine. Injection amount control method. (2) The load state of the auxiliary equipment is detected by at least one of detection of oil pressure of a power steering and detection of field current of an alternator. A fuel injection amount control method for a diesel engine. (3) While attenuating the doss pot amount,
Claim 1, characterized in that when there is a variation in the load condition, this variation is reflected in the damping characteristic.
The fuel injection amount control method for a diesel engine according to item 1 or 2.