JPS5841239A - Engine controlled in number of operating cylinders - Google Patents

Abstract

PURPOSE:To prevent previously misfire caused upon switching and engine stall, by a method wherein a means, deciding that the revolution number of an engine is lower than a predetermined revolution number and stopping the switching of the number of operating cylinders is provided, when the number of operating cylinders is switched in accordance with the load of the engine. CONSTITUTION:Even if an operating condition such as the load or the like is deviated from a partial cylinders operation zone, it is limited that the partial cylinders operation is returned to an all cylinders operation only when the revolution number N is higher than a preset revolution number N3, while, in the other cases, the partial cylinders operation is continued and the switching of the number of operating cylinders is not effected even if the output of an AND circuit 31 which is the set input of a flip flop 33, is switched from H to L. On the contrary, when the all cylinders operation is shifted to the partial cylinders operation, if the other conditions for the partial cylinders operation are satisfied, the switching of the cylinder number is never effected since the output of the AND circuit 31 which is the set input of the flip flop 33 is always on the L level in the zone in which the engine revolution number N is lower than the preset revolution number N3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder number control engine that performs partial cylinder rotation by cutting off fuel supply to some cylinders in a light engine load range.

In general, when an engine is operated under a high load condition, fuel efficiency tends to improve (a). Therefore, in a multi-cylinder engine, when the engine load is low, the supply of fuel and fresh air to some cylinders is cut and the operating pipes are stopped. By increasing the load on the remaining operating cylinders by that much, the overall fuel efficiency in the light load range was improved, and nine cylinder number control systems were devised.

hl, the first engine of this type that Honde Honjin applied for first.
11, the intake passage 1 is downstream of the crest valve 2 and connects the cylinders 1 to 1.
It branches midway into an active 11 intake passage 3 for φ3 and a rest 11 intake passage 4 for cylinders φ4 to φ6.

The cylinders φ1 to φ3 are installed on the intake boat, and the fuel injection valves a-C are the active cylinders that are constantly supplied with fuel and continue to operate. The control circuit 15 stops the p-injection in the engine light load range, forming a cylinder on the idle side.

A fresh air cutoff valve 5 is provided upstream of this idle-side intake passage 4, which also blocks the inflow of fresh air O when the operating body is stopped.

On the other hand, the exhaust passages are also an active inertial exhaust passage 7 connected to cylinders φ1 to 3, and an inactive exhaust passage S connected to cylinders φ4 to φ6.
The air-fuel ratio sensor 13 is installed in the merging exhaust passage 6 to detect the oxygen concentration in the exhaust gas, and the three-way catalyst 14 is installed downstream of the air-fuel ratio sensor 13. It is fed back to the circuit 15, and each cylinder φ1
~φ6Kfi is corrected so that the mixture is supplied to the air-fuel ratio at the stoichiometric air-fuel ratio.

An exhaust circulation passage 9 that connects to the idle side intake passage 4 of the shutoff valve SOT flow branches from the middle of the idle side exhaust passage 8.
An exhaust circulation valve 12 is interposed in the I-ring passage 9 and is linked to a diaphragm device 11 that responds to the negative pressure introduced when the three-way solenoid valve 100 is switched.

Based on the intake air amount signal from the air flow meter 16 and the O engine rotation speed signal from the crank angle sensor 17, the control circuit 15 also controls the amount of fuel to be injected from the fuel injection valves a to f based on the feedback signal described above. The air-fuel mixture is controlled to have a stoichiometric air-fuel ratio, and based on this, the air-fuel mixture is maintained at the easternmost point in the purification efficiency.

In the engine light load range, judging from the intake air amount signal, for example, the fuel injection valves df of cylinders φ4 to φ6 are
The control circuit 15 is configured to stop the O operation, simultaneously fully close the fresh air cutoff valve 5, and fully open the #P air circulation valve 12.
outputs a command, and from this point, cylinders φ1 to φ30 are operated by K.

In the case of ζO, by closing the shutoff valve 5, the entire amount of fresh air that has passed through the throttle valve 2 will be sucked into the working cylinders 1 to 3, and the intake air amount of each cylinder will be lower than immediately before ζO. Since the amount of fuel is doubled, the control circuit 15 switches the injection constant so that the amount of injection from the fuel injection valves 1 to C also doubles. By relatively increasing (doubling)], the cylinders φ1 to φ”3 are operated in an operating range with excellent fuel efficiency.

On the other hand, for the cylinders φ4P-φ6 on the idle side, the inflow of fresh air as well as fuel is cut off, but since the exhaust circulation passage 9 is opened, the exhaust gas discharged into the exhaust passage 8 on the idle side is almost 7. The intake air is drawn into the intake passage 4 on the idle side 11, and from this K, the intake negative pressure of the idle cylinders φ4 to φ6 is maintained at approximately atmospheric pressure.

Therefore, during the idle stroke of the cylinders φ4 to 60 on the idle side, the so-called pumping loss, which sucks circulating gas at almost atmospheric pressure, is kept extremely small, and the cylinders on the idle side φ4~φ6
In order to further improve fuel efficiency by eliminating the work spent on driving the engine, it also prevents unburned air from flowing into the combined exhaust passage 6KR from the idle cylinders φ4 to 6, thereby increasing the air-fuel ratio. 1
B's detection function ostta is avoided and the three-way catalyst 140 purification efficiency decreases.

By the way, in this device, partial cylinder operation is specifically performed by a control circuit shown in Figure 2.

20 is a comparator that compares the pulse width PL of the fuel injection signal with the pulse width P corresponding to a preset groove load; 21;
is the engine rotation speed Nt, which is also obtained from the pulse frequency
This is a comparator that compares with a preset low rotation speed N.]
, when the pulse width at which both comparators 20 and 21 are turned on is less than or equal to P and the engine speed is greater than or equal to approximately The enclosure 26, the fresh air cutoff valve, and the exhaust gas circulation valve O drive circuit 27 are operated at the same time.

It should be noted that the 24ti idle switch outputs an output to the % off circuit 23 during full engine idle switching to perform partial cylinder operation in the same manner as above.

As a result, all cylinders (
A 6 cylinder) operating range and a partial cylinder operating range (3 cylinders) are set.

Nine, simultaneous Kll! Based on the output of the engine/cooling water temperature sensor (not shown), when the engine cooling water temperature is low, partial cylinder operation at the idle plate is stopped.

However, when changing the control between partial cylinders and all cylinders in this way, especially when changing the number of cylinders to 0 in the low engine speed range, the air-fuel-ground ignition timing or the exhaust gas recirculation rate may momentarily become inappropriate. In this case, the operating cylinders would misfire, resulting in engine stall, especially in the low-load, low-speed range, partly because the inertia of the engine was small.

In order to solve this problem, it is an object of the present invention to provide an engine that controls the number of cylinders by detecting the engine load and rotation speed and stopping switching control of the number of cylinders in the low speed and low load range. .

Hereinafter, embodiments of the present invention will be described based on the drawings.

Fig. 4 is a block diagram showing the main parts of the present invention, and compared to Fig. 2, there is a new setting value Nt for the number of revolutions per engine.
, a comparator 30 that outputs a HI level signal when the value is higher than that, and two AND circuits 31 and 3.
2, a slip-flop 33 that is set and reset by signals from the AND circuits 31 and 32, and an inverter 34 that inverts the output of the AND circuit 23.
Based on the output of the 0 knob 33, the fuel injection layer disconnection circuit 25;
The fuel injection constant switching circuit 26, the fresh air cutoff valve, and the exhaust circulation valve drive circuit 27 are switched and controlled.

The AND circuit 31 outputs a signal at the %HI level when both the outputs of the comparator 30 and the outputs of the OVER circuit 230 are VC'HI, which sets the shift flip-flop 33 and switches its output to the %HI level.

Therefore, the O/O circuit 23 becomes %HfK during idle or during partial cylinder operation when the rotation speed N>Nl, and the comparator 30 becomes %HfK when the rotation speed N becomes N>Ns. In addition, from these K, the fuel injection layer disconnection circuit 25, the fuel injection constant switching circuit 26, the fresh air cutoff valve, and the exhaust recirculation valve drive circuit 27 operate simultaneously,
Perform partial cylinder operation.

Then, this partial cylinder operation is performed as follows:
However, since the AND circuit 32 connected to the reset input terminal sees the output of the comparator 30 and the inverted output via the inverter 34 of the O/R circuit 23, the rotation aN is Ns. Yoshi is also big,
And when the output of the output circuit 23 reaches %L level, the reset input changes to %HIK p1 All cylinders rotate Kp:bC
).

Here, the output of the output circuit 23 becomes %LI when the rotational speed N is N (N) or when the pulse width P is P > P.

This is a non-idling time when the idle switch 24 is turned off. Therefore, even if the operating condition deviates from the partial cylinder operation region (3 cylinder region in Figure 5) due to busy conditions, the engine returns to full cylinder operation. It is @ when the displacement rotation speed N is larger than N, and in other cases, even if the output of the AND circuit 31, which is the set input of the 7-lip flop 33, switches from 'Hl to QL1, the t″
! ! Partial cylinder operation continues and the number of cylinders is not switched.

Conversely, when transitioning from full cylinder operation to partial cylinder operation,
In the region where the carrot rotational speed N is lower than N, the output of the AND circuit 31, which is the 7-rip, 70-tug, 380-set input, is always at the Ll level, so even if all other partial cylinder operation conditions are met, , the number of cylinders O is not changed.

As described above, in the present invention, switching from partial cylinder to all cylinders or from all cylinders to partial cylinder operation is stopped in the low engine speed range (N < Ns in the above embodiment), so that low ( 9) It is effective in preventing engine stalls by preventing misfires due to fluctuations in air-fuel ratio and ignition timing that occur when changing the number of cylinders during reloading.

In the above embodiment, the limit rotation speed Ns in the low rotation range is set uniformly, but there may be a difference t between when switching from all cylinders to partial cylinders and when switching from partial cylinders to all cylinders. However, in addition to the 1st mK engine, there are also engines with cylinder number control that suck fresh air into the body stop air W during partial cylinder operation, and suck the discharged air into the active cylinders. The good news is that this is clearly a good thing.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the conventional device O, Figure 2 is a control circuit block diagram, and Figure #lE3 is its operating characteristic theory Jj11W.
J, No. 4111 is a block diagram of the control circuit of the misfire, and FIG. 5 is a diagram explaining its operating characteristics. 2... Throttle valve, 3... Working side intake passage, 4... Inactive side intake passage, 6... Fresh air cutoff valve, 9... Exhaust circulation passage, 12... Exhaust circulation valve, 15 ...Control enclosure, 24.
... Sputtleswiss f-120, 21, 80... Combaret/. 22.31.32...AND circuit, 25...Fuel injection amount cutoff circuit, 26...Fuel injection constant switching circuit, 27
...Drive circuit, 33...Flip-flop patent applicant Nissan Motor Co., Ltd. 1st issue Fig. 2 2) 4 Fig. 3 1ゝ41 d) Nso circuit (missing r1 Fig. 4 0 4) Figure 5 En','yrrnself (N 210-

Claims (1)

[Claims] means for determining that the engine is under a predetermined light load and the engine speed is at or above a predetermined low rotation speed; and means for determining that the engine is under no load; means for stopping the operation of the engine by cutting off the supply of fuel to the partial cylinders, and means for determining that the engine rotation speed is lower than the predetermined low rotation speed in the nine-cylinder control engine. and means for stopping switching of the number of cylinders p based on the discrimination signal.