JPS60190636A - Fuel injection timing control device in internal- combustion engine - Google Patents

Abstract

PURPOSE:To reduce the amount of fuel stuck to the inner wall of an intake-air passage, by providing a fuel injection time computing means for computing the time of the fuel injection for an auxiliary injection valve and a fuel injection timing setting means for setting the time of fuel injection at a time when the flow rate of intake-air is high. CONSTITUTION:There is provided an auxiliary fuel injection valve in the upstream section of an intake-air passage in addition to main fuel injection valves for engine cylinders. A fuel injection time computing means computes the tine of fuel injection for the auxiliary fuel injection valve in accordance with the operating parameters of the engine. A fuel injection timing setting means sets the time of fuel injection at a time when the flow rate of intake-air in the vicinity of the jet port of the auxiliary fuel injection valve is fast. With this arrangement it is possible to aim at atomizing fuel so that the amount of fuel stuck to the inner wall of the intake-air passage may be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a solvent injection timing control device for an internal combustion engine which is provided with a sub-injection valve for cooling intake air.

BACKGROUND OF THE INVENTION Internal combustion engines are already known in which, in addition to a main injection valve provided for each cylinder, a sub-injection valve is provided upstream of an intake passage, for example, in a surge tank or near a throttle body. The fuel injection from this sub-injector cools the intake air and improves the filling efficiency.

Output performance can be improved. In other words, as shown in Fig. 1, when the scandal TH^ of the intake air becomes low, the intake air amount 08 (quality - t) becomes gluttony.

Therefore, the 1 old Katorku Ti also improves. By the way, → If the intake width T HA is lowered to 50 C% 0 ℃.

Both intake air amount Ga and output torque T'l are 50-20/2
Improve by 73+50+9 crabs.

Figure 2 I-1 shows air-fuel ratio Δ/F vs. output torque 'l'H#J characteristics. As shown in FIG. 2, the total torque Ti for the air-fuel ratio A/F reaches a peak at a certain point (referred to as al: output air-fuel ratio), and the output torque T becomes lower than this peak whether rich or lean.

Further, as the intake width becomes lower, the output torque T, ) becomes higher as explained in FIG. 1. For example, the intake width is 'l'1
(When the output air-fuel ratio decreases from AH to 'f' HA L, 1'i at the output air-fuel ratio improves from 1 to b2, increasing by ΔT1. However, if the distribution deteriorates, Tanae will assume that in a 4-cylinder engine, the average air-fuel ratio is the output air-fuel ratio a1 ((combined), but in this case, the air-fuel ratio A/F of the 2 cylinders becomes a2,
The air-fuel ratio A//F of the deaf 2 cylinder is a5 and the 1 distribution is ΔA
Suppose that only /F' worsens.

The torque at that time is the average of the torque for air-fuel ratio A2 and the torque for 33 (l) Only 5 will be produced. In the end, even if you aim to improve output performance by ΔT1 by lowering the intake width THA, if the distribution deteriorates by 1, Δ
It only improves by T2. If the distribution deteriorates further, b
In some cases, the output torque Ti becomes lower than l, and the output torque Ill becomes higher if fuel is not injected from the sub-injector.

When the distribution deteriorates as shown in Fig. 3, there is a problem that the output torque Ti cannot be sufficiently improved even if the intake air amount Ga is increased by cooling the intake air by fuel injection from the sub-injector.

Purpose of the Invention The purpose of the invention is to inject fuel when the intake flow velocity near the nozzle of the sub-injector is as high as possible and to atomize the injected fuel by air friction, in view of the problems with the conventional type described by Dojo. The purpose is to atomize the fuel so that it is inhaled together with the intake air, thus improving distribution by reducing fuel adhesion.

Structure of the Invention The structure of the present invention for achieving the stated objectives is shown in FIG. That is, in an internal combustion engine equipped with a main injection valve provided for each cylinder and a sub-injection valve provided in common for each cylinder in the upstream portion of the intake passage, the opening time calculation means for fuel injection The fuel #4 injection timing setting means (I
'J: The fuel injection time is set at a time when the intake air flow velocity near the injection port of the sub-injector is early.

Actual example The present invention will be explained in detail below with reference to one drawing.

First, the present invention will be explained in detail using FIG. 4(A), FIG. 4(B), and FIG. 5.

FIG. 4(A) and FIG. 4(P,) show the behavior of fuel particles when the intake flow rate is fast and slow, respectively. Fourth
As shown in Figure 19(A), when the intake flow rate is high, atomization due to air friction is actively carried out, and as a result, fC, the kinetic energy given during injection, increases.

- When considered per grain, it gradually becomes smaller, and the downward force (this is called the penetration crab F) gradually becomes smaller compared to the force that is pushed by the nine ki (called Fx).

Then, the flight direction of the fuel particles (the direction of the resultant force of the trenches Fx and F) gradually approaches the direction of the intake air flow.

Fuel is drawn in together with the intake air. On the other hand, as shown in FIG. 4 CB), when the intake flow rate is small.

As a result, atomization due to air friction is not promoted and the flight distance is short because Fy is larger than Fx.

Fuel particles will stick to the intake pipe wall button. For these reasons, it is better to inject when the intake flow velocity is higher.

As shown in Figure 5, the amount of adhesion in each furnace is reduced, and therefore,
distribution will be better.

Next, with reference to FIG. 6, we will briefly explain the time required for the FC fuel injected from the sub-injector to atomize and be inhaled into the combustion chamber (fuel arrival time). The atomized fuel that is injected from the engine forms a mixture with the intake air and is inhaled into the combustion chamber, but it takes a certain amount of time from the time it is injected until it is inhaled.This is called the fuel arrival time.

This fuel sting arrival time 1 (ke" f = 4/V, where 5, t = distance from sub-injection valve to intake valve ■ = given by intake flow velocity, ru. More realistically, Q; 1 and ■ are constant It is not a function of the crank angle θB), so it is 1, tinJ = sub-injector sub-injector At the start of injection
It depends. In other words, 'inj becomes 11 (11) when the intake flow velocity V is small near the straight curve where the valve begins to open or closes, and becomes 73 when the valve begins to open or closes.
When the flow velocity ■ is large, 1 ( becomes small. In Fig. 6, the horizontal axis shows the crank angle (CΔ) and time, and the vertical axis shows the intake speed V and injection signal S, and the numbers 1, 3, and 4 .2
represent the intake line cape of the first cylinder, the intake line of the third cylinder, the intake line culm of the fourth cylinder, and the intake stroke of the second cylinder, respectively. At this time, when the intake valve closes and V=O, ' ``end
The fuel and intake air (shaded area in the figure) are as follows.

Instead of being inhaled into the targeted cylinder, it is inhaled during the next intake stroke or into the next cylinder. Therefore, fuel #4 injection is at 11
If the process does not end with a difference of 15 tend -tf, the air-fuel ratio cannot be controlled to the requested air-fuel ratio. in this way.

In addition to simply injecting when the intake flow rate is high, it is also necessary to consider the time it takes for the fuel to arrive.

FIG. 7 is an embodiment of the fuel injection timing control device for an internal combustion engine according to the present invention. FIG. In Figure 7,
A main injection valve 4 is provided in the vicinity of the intake valve 3 in the intake passage 2 of the engine body 1 . There are as many main injection valves 4 as there are cylinders. Further, a sub-injection valve 6 is provided on the upstream side of the intake passage 2, for example, in the surge tank 5. Note that this sub-injection valve 6 is common to each cylinder. Furthermore, the intake passage 2 is provided with an intake pressure sensor 7 that generates an analog voltage according to the intake pressure (i).
]'''CΔ Crank angle LW sensors 9 and 10 are installed to generate an automatic position signal every time the engine rotates.

The control circuit 17 uses signals from the intake pressure sensor 7 and crank angle sensors 9 and 10 to control the main and sub-injection valves 4 and B. There is.

It! of FIG. 7 with reference to 70-Booyat of FIG. The operation 1'E of the control circuit will be explained. First, the intake flow velocity V is
V = aθ2+1)θ+c ,, -(1) However, a
= ka, Q2 + ka2Q 10 to 35・, -(2)I
)”” b+Q2+kb2Q +kb3...(3)
c = kc, Q,' -4-kC2Q -1-kc5
-...(4) Assume that it can be approximated by θ 2 ink angle ("CA). In addition, the constant kall ka2
'... is determined by the intake pipe length, diameter, etc., and can be determined experimentally. Step 8 in Figure 8
011d predetermined 2 ink angle, fr:, for example 1'80'C
The process starts every Δ, and in step 802, Q corresponding to the intake groove data calculated by another routine (not shown) and stored in [4A Ll in the control circuit 11 is read out.

Next, in step 803, the above formulas (2) and (3)
, r4) to calculate a, l), and C. In step 804, the integral value of the flow velocity V is cleared and initialized.

Steps 805 to 8]1 are for setting the injection end stage θC. In step 805, θ is set to θend, Δθ
shall be. Here, θ. . d1 Figure 9 (A), Figure 9 (
As shown in 1')), this is the crank angle at which the flow velocity V becomes 0, and is determined by the valve timing and the like. Stage, Phantom 1 at 806. In step 807, the flow velocity ■ is calculated using equation (1).

Δ84−V XΔθ, and further, step 808
Calculate the integral value S of the flow velocity V. And step 80
At step 9, the integral value S is transferred from the sub-injection valve 6 to the intake valve 3.
As a result of comparing the distance mt to , if s<1, then
At step 810, Δθ is subtracted from θ, and step 8
06~B[]? fe repeat.

If S>t, the injection end θC is determined in step 811.

Next, in step 812, the injection start time θ is determined. of.

θ. ←θ0−τ′/ζ, where τ1 is a value obtained by converting the required injection time τ of the sub-injection valve 6 calculated by another routine (not shown) into a crank angle.

However, T180 is the time required for i80'cA rotation,
It can be calculated by In addition, at step 811,
The crank angle θ corresponding to h corresponds to time tend-1 (in FIG. 6).

Next, steps 813 to 817 are performed in step 81 described above.
The end of injection θ was stopped at 1,812.

and onset θ. This is to set V to a region where the intake flow velocity V is faster. In other words, Ste, Bu 813, L length,
End of injection θ. Based on the intake flow velocity V1 at step 814, 11f injection start period θ. In step 815, the two are compared. That is, it is determined whether the state is in FIG. 9(A) or in the state in FIG. 9(T3). In the state shown in FIG. 9A, that is, ■1≧■2, even if the injection timing is advanced further, the region where the intake flow velocity V is high will decrease. Therefore, in this case, flow proceeds directly to step 818 without doing anything. Further, in the state shown in FIG. 9 CB), that is, Vl<2, the region where the intake flow velocity V is high becomes larger by advancing the injection timing. Follow/Step!
Injection end θ at 316,817. , and injection start time θ.

is advanced by Δθ and steps 813 to 815 are repeated. As a result, if ■1≧v2, that is, in this case, Vl and v2 are approximately equal, the flow proceeds from step 815 to step 818. As a result, Figure 9 (
I3] and the end of injection θ. is θ. This means that the injection start time θ0 has progressed to 00'.

In step 81B, the end of injection θ posted as described above. , the injection start point θ0 is determined by the time “C” using the rotational speed data.
%L in terms of o'O, and time t in step 819. , to
Vice 11. ] The two timer counters for driving the injection valve 6 are set, and the routine ends at step 820.

In this way, all the atomized and vaporized smoke in the area where the intake flow rate is high is inhaled into the targeted cylinder.

Improved controllability of over-tightness. Improved drivability, emitter, and vibration.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, as described above, the injection timing of the sub-injector is set as described above, so that injection can be performed at a location where the air flow velocity is as high as possible.

The amount of fine smoke particles can be measured, reducing the fP rate adhering to the inner wall of the intake pipe, resulting in improved distribution.

e, the air cooling effect is no longer offset by poor distribution.

[Brief explanation of the drawing]

Figure 1 is a graph showing the intake air temperature vs. output torque and intake air amount characteristics, Figure 2 is a graph showing the air-fuel ratio vs. output torque characteristics, and Figure 3 is a graph showing the air-fuel ratio vs. output torque characteristics.
The figure is a block diagram showing the configuration of the present invention.
11 (A), 4th rglJ (B,) Ha MIJl
Figure 5 is a graph to explain the behavior of fuel particles near the f-injector, Figure 5 is a graph showing the intake flow velocity vs. fuel deposition rate characteristics, and Figure 6 is the fuel arrival time? 11-Timing diagram to illustrate, F
Jj 717J is an overall block diagram showing an embodiment of the fuel #4 injection timing control device for an internal combustion engine according to the present invention, FIG. 8 is a flowchart for explaining the operation of the control circuit in FIG. 7, and FIG. FIG. 9(A) and FIG. 9(B) are timing charts for supplementary explanation of the flowchart of the eighth drop. 1...Engine body 4...Main injection valve 6...Sub-injection valve t,,, tc'...Injection path It'O 'C) Figure 2 ((53 Figure 4 (A) Figure 5 Figure 4 (B) Figure 6 Figure 9 (A) tO'Ctend (B) 10tOLCLC[end

Claims (1)

[Scope of Claims] 1. In an internal combustion engine equipped with a main injection valve provided for each cylinder and a sub-injection valve provided commonly in the upper part of the intake passage, the operation of the engine is controlled. a fuel injection time calculation means for calculating a fuel injection time of the sub-injection valve according to a state parameter; and a fuel injection timing setting for setting the fuel injection time to a time when the intake flow velocity near the injection port of the sub-injection valve is early. 1 υ per injection] control device for an internal combustion engine which is characterized by having a means. 2. The smoker injection timing setting means sets the fuel injection timing (
τ) ([6) is the end of the intake stroke T of each cylinder of the engine.
From the sub-injector to the intake valve sequence, the time (te+1d-1(
), and an injection start time setting means for setting the start time (1o) of the disclaimer time (1) to the set end time. The intake flow velocity (■,) at the final stage (tc) near the nozzle port of the sub-injector and the intake flow velocity at the beginning stage (1o) (
v2), and when the intake flow rate (v2) at the start period (1o) is greater than the intake flow rate [vl] at the end period (1o), the start period and the end period are set at the same time. Claim 1, further comprising an injection timing adjusting means that advances the injection timing by an amount of 1° to make the intake flow rate at the advanced start period (1o) approximately equal to the intake flow speed at the advanced end period (t,'). Fuel injection timing control device for internal combustion engines.