JPS608434A - Cylinder number controlled internal-combustion engine - Google Patents

Abstract

PURPOSE:To switch to a whole-cylinder-operation without delay at the time of an acceleration by providing a changing ratio detecting means of an engine load on a cylinder number controlled engine for judging cylinder numbers driven based on the changing ratio. CONSTITUTION:An acceleration start detecting circuit 19 and an acceleration end detecting circuit 20 are provided on a cylinder number controlled engine. Both detecting circuits 19 and 20 detect a differential value against a crank angle (or time) of a suction air volume Q to compare with a set value and output a signal. At the time of sudden acceleration, a throttle valve is opened suddenly to increase the suction air volume, so that the differential value of the suction air volume becomes bigger to exceed the set value almost without any delay from the accelerating operation and to be switched to a whole-cylinder- operation by a signal '1' outputted from the acceleration start detecting circuit 19.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an improvement in a cylinder number controlled internal combustion engine that suspends operation of some cylinders depending on engine operating conditions.

<Prior art> In general, when an internal combustion engine is operated under a high load condition, fuel efficiency tends to improve. A cylinder number control internal combustion engine has been proposed in which the fuel efficiency in the remaining operating range is improved by relatively increasing the load on the remaining operating cylinders.

A conventional engine of this type is one shown in FIG. 1, which is controlled to switch between partial cylinder operation and full cylinder operation based on signals from various sensors and switches depending on the operating state. In the figure, the control unit 1 includes a vacuum switch that detects the intake pipe pressure downstream of the throttle valve.
y-2h, 2B.

Thermopulp 3 for EGR control that detects the cooling water temperature and opens at low temperature, select switch 4 that detects the 1st and 2nd gear positions of the transmission, solenoid pulp 5 for throttle adjuster control, backup lamp switch T1 ignition switch 8. Signals from the ignition coil 9 are input, and switching control is performed between partial cylinder operation and full cylinder operation according to the operating state detected based on these signals.

Figure 2 shows the relationship between the operating status and the number of operating cylinders and its purpose. For operating cylinders, ○ indicates operation, × indicates off,
Regarding each sensor type, ○ indicates that the signal is used to detect the operating state, × indicates that it is not used, and specifically, partial cylinder operation is performed during idle link, deceleration, and low speed driving. Otherwise, all cylinders are operated.

By the way, in such a cylinder number controlled internal combustion engine, when the intake pipe negative pressure decreases during normal operation, partial cylinder control is performed until the intake pipe negative pressure reaches the first set value pOA detected by two vacuum switches. Driving is not canceled, and
Once switched to all cylinder operation, vacuum switch 2
The second set value PoB (<PoA
(comparison in absolute value)) The configuration is such that the switch to partial cylinder operation does not occur until the number of cylinders decreases below (see Fig. 3). For this reason, even if you want to cancel partial cylinder operation and switch to full cylinder operation, it will not be canceled until the intake pipe negative pressure becomes smaller than a predetermined value. Depending on the volume of the intake manifold and engine speed, there may be a momentary delay, and since the load is already high when the switch is switched, the difference in torque caused by the switch is large, causing problems such as sudden shock. was there.

<Object of the Invention> The present invention has been made in view of the above-mentioned conventional problems. By detecting the start of acceleration in a short time, it is possible to smoothly switch between partial cylinder operation and full cylinder operation during acceleration. An object of the present invention is to provide an internal combustion engine with cylinder number control that allows the control of the number of cylinders.

<Structure of the Invention> Therefore, the present invention provides a means for detecting the rate of change in load of an engine, a means for determining the rate of change in load detected by the means, and a means for determining whether to switch between partial cylinder operation and full cylinder operation. The configuration includes the following.

<Example> Examples of the present invention will be described below based on the drawings. 1st
In FIG. 4 showing the embodiment, the cranking detection circuit 11 sets the output level to 11 when the starter switch S is in the ON state 5TOO. The water temperature detection circuit 12 whispers an output level of 1 when the engine cooling water temperature Tc is at the set temperature Tco.
〃. The vehicle speed detection circuit 13 determines that the vehicle speed Sp is the set value Spo.
At low speeds such as starting, the output level is set to 1.

The gear position detection circuit 14 sets the output level to whisper 1 when the gear position of the transmission is set Go, for example, first speed and reverse. The rotational speed detection circuit A15 sets the output level to 11 when the engine rotational speed NE is greater than the set value □NE+. The rotation speed detection circuit B16 detects the engine rotation speed N.
When is smaller than the set value NE2 (<NEt), the output level is set to 1. The output terminals of each of the above detection circuits are all connected to the first
The input terminal of the OR element 21 is connected to the input terminal of the OR element 21. The intake pipe pressure detection circuit A17 detects that the intake pipe pressure (absolute pressure) P is the set value po.
When it is greater than A, the output level is set to 1. The intake pipe pressure detection circuit B18 detects that the intake pipe pressure (absolute pressure) is the set value po.
When B is smaller than PG A, the output level is set to “1”.
〃.

Output terminal of intake pipe pressure detection circuit A17 and intake tube 22
It is input to set terminal S and set terminal R of.

The acceleration start detection circuit 19 sets the output level to 61 when the differential value aQla (::) of the intake air amount Q with respect to the crank angle is greater than the set value KA.

The output terminal of the output circuit 19 and the output terminal of the acceleration end detection circuit 20 are connected to the set terminal S of the second 7-lip 70-tube 23, respectively.
and the reset terminal R.

The output terminal of the first 7-lip flop μ-tub 22 and the output terminal of the second flip-flop 23 are connected to a second OR gate.
connected to the input terminal of the element 24 and connected to the input terminal of the first OR element 2
1 and the output terminal of the second OR element 24 are connected to the third
The output terminal of the third OR element 25 is connected to the input terminal of the drive circuit 260.

When the output level from the third OR element 25 is (S 1 //), the drive circuit 26 operates all the cylinders to perform all-cylinder operation, and when the output level is 5077, some cylinders are stopped and the drive circuit 26 operates as shown in FIG. A switching operation is performed to perform cylinder operation.

Next, a series of operations of this embodiment will be explained.

At least one output level of the detection circuits 11 to 16 is '1'
〃, the output level of the first OR element 21 is SS
1//, and the output level of the third OR element 25 also becomes &1, so that the drive circuit 26 performs all-cylinder operation. Specifically, cranking detection times wr
During cranking, the water temperature detection circuit 1 is detected by 11.
2, during first speed and reverse operation, detected by the rotation speed detection circuit Ai5, at high speed rotation above a predetermined speed, and rotation speed below a predetermined speed detected by the rotation speed detection circuit B16. All cylinders are operated during low speed rotation (idling).

On the other hand, the output level of the intake pipe pressure detection circuit A17 is 1.
When , that is, the intake pipe pressure P rises to the set value PO.
When the load exceeds A, the first flip-flop 22 is set and its output level becomes 11, so the output level of the second OR element 24 and third OR element 25 becomes \1 in sequence. //The drive circuit 26 performs all-cylinder operation. After that, when the intake pipe pressure decreases below the set value poB and a low load condition occurs, the first flip-flop 22 is reset and the level becomes (j Q l
/, so the output level of the second OR element 24 is SS
O//, the output level of the first OR element 21 is 1
During operations other than the above-mentioned operations in which the output level becomes 0, the output level of the third OR element 25 becomes O, and the drive circuit 26 performs partial cylinder operation.

The above-described switching of the number of operating cylinders during steady operation is performed in the same manner as in the conventional example shown in FIG. However, in the past, acceleration was detected when the intake pipe pressure detected by the intake pipe pressure 1T exceeded the set value pOA, so as mentioned above, there was a delay in switching from partial cylinder operation to full cylinder operation. This resulted in poor acceleration/velocity performance and increased friction during switching.

Therefore, in the present invention, the start of acceleration is detected by detecting the rate of change in the load, and as a means to prevent this, an acceleration start detection circuit 19 is provided in this embodiment. Specifically, the acceleration start detection circuit 19 determines the amount of change in the intake air amount within a unit crank as a differential value θQ/QC based on detection means such as an air flow meter, crank angle sensor, etc. and signals from the detection means. and a determination avoidance unit that sets the output level to whisper 1 when the value exceeds the set value KA.

Now, when driving where the load suddenly increases, specifically when driving with sudden acceleration, the throttle valve should be suddenly opened by depressing the accelerator pedal from a low-load driving state, as shown in Figure 5. However, due to the capacity of the intake pipe and the inertia of the air, there is inevitably a delay in the rise of the intake pipe pressure itself, so in the intake pipe pressure detection circuit, a time delay is required to set the 7 lip-flop 22 when P>PoA. arise.

However, the intake air amount rises relatively rapidly, and therefore the slope of the rise, that is, aQlaC, is large, and the output level of the acceleration start detection circuit 19 exceeds the set value with almost no delay in response to the acceleration operation. becomes ts 1 tt. As a result, the second flip-flop 22 is set and its output level becomes XXIN, and the output levels of the second OR element 24 and the third OR element 25 are sequentially set to XXIN.
//, the drive circuit 26 can quickly switch from partial cylinder operation to all cylinder operation, and good acceleration performance can be obtained, and the switching can be performed at a stage where the difference in torque due to the change in the number of operating cylinders is still small. The shock at the time of switching is also almost eliminated. In this way, after switching to all-cylinder operation and performing acceleration operation, when the throttle opening degree is reduced and the transition is made to steady operation, the aQlaC
<When it becomes 0, the output level of the acceleration end detection circuit 20 becomes SS 1 // and the second flip-flop 23
is reset and its output level is 5 (SS □ //
becomes. Next, the intake pipe pressure also decreases rapidly, and when P<PQB, the output level i of the intake pipe pressure detection circuit B1fi
i% 1 #, the first flip-flop 22 is also reset, and its output level becomes (S Q /I).
The output level of the second OR element 24 becomes 10. In this state, the output levels of normal detection circuits 11 to 16 are all %
If Q is /1, the output level of the first OR element 21 is also '
110//, the output level of the third OR element 25 becomes XXQ/l, and the drive 26 switches from the multi-cylinder operation to the partial cylinder operation.

FIG. 6 shows a second embodiment of the present invention, in which the acceleration detection circuit 3
1, when the differential value of the throttle valve opening θ with respect to the crank angle C is greater than the set value KB, the output level is XX1.
// is provided, and its output terminal is connected to the set terminal of the 7 lip-flop 22 together with the output terminal of the intake pipe pressure detection circuit A17. The output terminal of the intake pipe detection circuit B18 is connected to the reset terminal of the flip-flop 22, as in the first embodiment.
The output terminal of 2 is directly connected to the input terminal of OR element 25.

In this device, when an acceleration operation is performed, aθ/aC rises rapidly as shown in FIG. 7 and immediately exceeds the set value KB, which causes the output level of the acceleration start detection circuit 31 to reach 1. Then, the flip-flop 22 is set, the output level of the OR element 25 is set to 1, and the drive circuit 26 switches to all-cylinder operation.

In this way, as in the first embodiment, it is possible to switch to all-cylinder operation with almost no delay after the start of acceleration. still,
As a means of knowing the opening degree of the throttle valve, in addition to direct detection, detection of an accelerator pedal, throttle linkage, throttle wire, etc. can be used instead. When the acceleration is finished, as in the first embodiment, p (p o B) is reached, thereby switching to partial cylinder operation.

FIG. 8 shows a third embodiment of the present invention, in which an acceleration start detection circuit 32 is configured to calculate the differential value -θP/θC of the intake pipe negative pressure (-P) with respect to the crank angle C so that the set value is less than the set value Kc. A device is installed so that the output level is 1 when the output is large.
Its output terminal is connected to the flip-flop 220 set terminal.

In this case as well, as shown in FIG. 9, the acceleration is N1, so the operation is immediately switched to all-cylinder operation, and thereafter, in the same way, when p (p o B) is reached, it is switched to partial j! rotation.

FIG. 10 shows a fourth embodiment of the present invention, in which the maximum value of the cylinder pressure is determined by the crank angle C (number of OC cycles) of Pcmax.
The current differential value θP c m a x /θC is the set value K
An acceleration start detection circuit 33 whose output level becomes XX11/ when D is exceeded is provided, and its output terminal is connected to the circuit fA of the flip-flop 22. The rise υ of θPcmax/δC at the start of acceleration of this object rapidly increases in approximately proportion to -δP/δC, and immediately KK
Switch to all-cylinder operation beyond
When turned on, it switches to partial cylinder operation.

The embodiment shown above is configured to detect the start of acceleration by prompting a change in the load of the unit crank angle, but it can be Alternatively, the acceleration detection may be performed by prompting a change in the amount that changes depending on the load per unit time or a change in the load.

For example, as corresponding to the above embodiment, the unit time of the intake air amount Q1, throttle opening θ, intake pipe negative pressure (-P), maximum cylinder pressure Pcmax, etc. is changed by 1taQ/
at, aQ/at, -θP/θt, -δPcmax/a
The configuration may be such that the start of acceleration is detected when t exceeds each set value.

In addition, when a digital computer is used for the control circuit, knowing the load change per unit time means knowing the amount of change for each sampling period. In addition to the methods described above, changes in load can also be determined by checking vehicle acceleration, engine drive torque changes, combustion noise changes, exhaust pressure fluctuations, and the like.

<Effects of the Invention> As explained above, according to the present invention, the start of acceleration is detected by determining the rate of change of the engine load with respect to the crank angle or time, and the change from partial cylinder operation to full cylinder operation is performed based on the change in engine load. Since the configuration is configured to perform switching control, it is possible to switch to all-cylinder operation with almost no delay after the start of acceleration, thereby improving acceleration performance, and
The effect of reducing the shock by reducing the difference in torque at the time of switching is achieved.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an example of a conventional internal combustion engine with cylinder number control; Fig. 2 is a diagram showing the relationship between the operating state and the number of operating cylinders in the same engine, and its purpose; Fig. 3 is a diagram showing acceleration operation in the same engine. FIG. 4 is a block diagram showing the first embodiment of the present invention; FIG. 5 is a diagram showing various state quantities during acceleration operation in the same embodiment; FIG. 6 is a block diagram showing a second embodiment of the present invention, FIG. 7 is a diagram showing changes in various state quantities in the same embodiment, and FIG. 8 is a block diagram showing a third embodiment of the present invention. 9 is a diagram showing changes in various state quantities during acceleration operation of the same embodiment as above, and FIG. 10 is a block diagram showing a fourth embodiment of the present invention. 11...Cranking detection circuit 12...Water temperature detection circuit 13...Vehicle speed detection circuit 14...Gear position detection circuit A 15...Rotation speed detection circuit A16...Rotation speed detection circuit B 17. ...Intake pipe pressure detection circuit A 18
...Intake pipe detection circuit B 19°31.32.33...
・Acceleration start detection circuit 21゜22.25...OR element 26...Drive circuit object Applicant: Nissan Motor Co., Ltd. Representative Patent Attorney Fujio Sasashima

Claims (1)

[Claims] In a cylinder number control internal combustion engine equipped with means for switching the number of operating cylinders that suspends operation of some cylinders according to operating conditions, means for detecting a rate of change in engine load with respect to crank angle or time, and detection by the detecting means. and means for determining the number of operating cylinders to be switched by the operating cylinder number switching means based on the load change rate.