JPS58119941A - Cylinder-number-controlled engine - Google Patents

Abstract

PURPOSE:To reduce the oxygen in the new charge introduced into a catalyzer by reducing the supply amount of the new charge in accordance with the temperature. CONSTITUTION:During the partial operation of cylinders, when the temperature of the second catalyzer 8 is under a set value, a control circuit 15 opens the second new charge supply valve 20 on the basis of the signal of a thermal sensor 21 to detect the temperature of the second catalyzer 8, and introduces the new charge into intermission side cylinders #1-#3. Meanwhile, when the temperature of the catalyzer 8 is over the set value, the second new charge supply valve 20 is controlled to be closed in accordance with the temperature for throttling the new charge introduced from an auxiliary passage 19. This construction permits to reduce the supply amount of the new charge, and control the introduction amount to the second catalyzer 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improvement 1cII of a cylinder number control engine that performs partial cylinder operation by deactivating some cylinders in a light engine load range.

In general, when the engine is operated under a high load, the fuel efficiency tends to increase.For this reason, in a multi-cylinder engine, when the engine load is low, the fuel supply to some cylinders is cut and the operation is stopped. The remaining operation time is 4.
The load V of the 111 cylinders is relatively 1.6, and a nine-cylinder number control carrot was considered to improve overall fuel efficiency in the light load range. (See patent Ws53-72849) This type of engine was previously filed by Kltj.

As shown in the 1st rkJK, the exhaust passage 1 is divided halfway into the idle exhaust passage 2 and the active exhaust passage 3 corresponding to cylinders 1 to 3 on the idle side and cylinders 4 to 6 on the active side. ing.

Then, in the light load range of the engine, cylinders 1 to 3 operate.
When stopping the engine, a control device (not shown) controls the intake air in response to cylinders 1 to 3 based on KFi, for example, an intake air amount signal from an intake air amount needle (not shown) or a rotational speed signal from an ignition coil, etc. The fuel injection ff (not shown) installed in the first cylinder is kept fully closed, the fuel supply i is cut, and only the fresh air introduced through the throttle valve 4r of the intake passage 5 is closed. Supply to ~S3. This is from K.
Reduced to 4 pumps in cylinders 1 to 3 on the idle side
At the same time, partial cylinder operation 1 is performed by operating only the active cylinders 4 to 6.

By the way, in this engine, during normal operation (when all cylinders are operated), K discharges the combusted exhaust gas from all cylinders 1 to 6 in the same way, or when operating cylinders 4 to 6 during partial cylinder operation. From 6 onwards, the combustion gas stops @ cylinders 1 to 3.
Fresh air is directly discharged from the

Therefore, when a three-way catalyst i is used as this exhaust treatment device 6, KFi, a! Working side cylinders 4 to 6 as shown in J
A first catalyst 7 that converts only the exhaust gas from the cylinders to +r#, and a second catalyst 8 that mainly purifies the exhaust gas g&r from the idle cylinders 1 to 3 during all-cylinder operation, and downstream of the confluence of both exhaust passages 2 and 3.

[L Oxygen sensors 9 and 10 are installed upstream of these catalysts 7 and 8, respectively, and their air-fuel ratio detection signals are sent to the aforementioned control device.

During zero partial cylinder operation, the injection amount of the corresponding fuel injector is corrected according to the detection signal of the first oxygen sensor 9 so that the air-fuel mixture at the stoichiometric air-fuel ratio is obtained in the active cylinders 4 to 6. During all-cylinder operation, the injection amounts of all fuel injection valves are corrected according to the detection signal of the second oxygen sensor 10, and all cylinders 1 to 6 are controlled to have the stoichiometric air-fuel ratio.

This trap increases the conversion efficiency of the first and second catalysts 7 and 8, and the corresponding cylinders 1 to 3. It promotes the reaction with the exhaust gas from Steps 4 to 6, thereby purifying the exhaust gas.

However, in this conventional example, during one partial cylinder operation, fresh air flows into the second catalyst 8 from the idle cylinders 1 to 3. When the temperature WIL of the catalyst 8 is high, K is set to 1 so that the function of the catalyst 80 deteriorates severely due to the large amount of oxygen contained in the fresh air! >, this has been going on for a long time 9
If the catalyst 8 is returned, there is a problem in that the durability itself of the catalyst 8 deteriorates.

This invention was made by focusing on such conventional problems, and includes a temperature sensor i for detecting the temperature V of the second catalyst installed downstream of the confluence of the exhaust passages on the idle side and the operating side. A valve i is provided to throttle fresh air supplied to the side cylinders, and when the catalyst temperature FjIi exceeds a set value during partial cylinder operation, ff? By closing and reducing the supply amount of fresh air, the oxygen V in the fresh air flowing into the catalyst is reduced.
Reduce it.

The purpose and purpose of providing a KLI cylinder number control engine is to solve the above problems.

One of the following inventions? The explanation will be based on the drawings. FIG. 2 is a diagram showing an embodiment of the present invention. In this additional example, cylinders 1 to 3 are stopped (combustion V is stopped) in the light load range of the engine, and cylinders 4 to 6 are continuously operated.
lIj is replaced with FIG. 1.

Then, these cylinders on the idle side 1 to 3 and the cylinders on the operating side 4 to
The intake passage 5 is divided downstream of the throttle valve 4 into an inactive intake passage 11 and an operating 1 m@shift passage 12 corresponding to the intake passage 6.

Among these, the upstream of the idle side intake passage 11 *[a.

A fresh air cutoff valve 13 is installed, and when the actuating bodies of the cylinders 1 to 3 are stopped, that is, when the partial cylinder operation is performed, Kf! When negative pressure (for example, engine suction negative pressure) is transmitted to the diaphragm device 14 by a command from the I control circuit 15, the passage 111 is closed.

At this time, fresh air is connected to the intake passage 5 upstream of the throttle 9P4 (and the intake air amount needle 16) so that the fresh air on the upstream side of the throttle valve 4 is directly introduced into the cylinders 1 to 3 on the idle side. Shutoff valve 13
A fresh air supply passage 17 connects to the downstream idle air passage 11 .

A fresh air supply valve 18 is interposed in the middle of the fresh air supply passage 17, and the passage 17' is opened in response to a command from the control circuit 15 during one-part cylinder operation.

Next, an auxiliary passage 19 is formed in this fresh air supply passage 17, and this auxiliary passage 19 passes through the fresh air supply valve 18t.
9VcFi, and a second fresh air supply 9P20 that is opened and closed according to commands from the control circuit 15 is interposed as will be described later.

On the other hand, the exhaust passage 1 is also divided halfway into a resting side exhaust passage 2 and an operating side exhaust passage 3 corresponding to the resting side cylinders 1 to 3 and the working side cylinders 4 to 6.

Of these, the working side cylinder 4 is located downstream of the working side exhaust passage 3.
The first catalyst (three-way catalyst) 7 that purifies the exhaust pipe from ~6
downstream of the confluence of the exhaust passages 3 and 20 on both the operating side and the idle side.
Exhaust from Step 3 II - Second catalyst that converts into salt (three-way catalyst)
8 is installed.

This second catalyst 8 is provided with a temperature sensor 21 that detects the temperature of the catalyst 8D@, and its detection signal is input to the control circuit 15.

Furthermore, oxygen sensors 9 and 10 are installed upstream of the first and second catalysts 7 and 8, respectively, and their detection signals are also sent to the control circuit 15.

Then, the control circuit 15 determines the basic fuel injection amount for each cylinder 1 to 6 based on the intake air jli signal from the intake air indicator 16 and the rotational speed signal from the ignition coil 22. Temporarily calculate this t
The fuel injection amount of the fuel injections 5Pa-f is corrected according to the detection signal of the second oxygen sensor 10 and is provided corresponding to each cylinder 1 to 6 so as to obtain a mixture at the stoichiometric air-fuel ratio. r Feedback control.

On the other hand, the control circuit 15 1 determines, for example, from the intake air amount signal, that in the light engine load range, the fresh air connection 913'jr
Close, fresh air supply 5P18r opens and introduces fresh air r from the fresh air supply passage 17 upstream of the throttle 94 and intake air position needle 16 into the cylinders 1 to 3 on the contact side and fuel injection 9Pa to e
Control is performed to keep the cylinders fully closed, and the fuel supply V to the cylinders 1 to 3 on the inactive side is cut to stop their operation and perform partial cylinder operation.

In this case, the engine output r just before that (when operating all cylinders)
In order to maintain the same value, the injection constant is switched by the KIIJ control circuit 15FPg so that the basic injection amount from the fuel injection valves df is doubled in the operating cylinders 4 to 6. At the same time, the injection amount is corrected according to the detection signal from the first oxygen sensor 9.

The operating cylinders 4 to 6 are controlled to have the stoichiometric air-fuel ratio.

In this way, optimum combustion is achieved in each cylinder 1 to 3 degrees 4 to 6 during full-cylinder operation and partial cylinder operation, and the conversion efficiency is maintained at its best with one catalyst 7 degrees 8. However, in this embodiment, during this partial cylinder operation, the temperature of the second catalyst 8! If [ exceeds the set value i,
The amount of fresh air supplied to the cylinders 1 to 3 on the idle side is decreased. In addition, when the catalyst 8 is at high temperature, 1
It prevents the function of the catalyst 80 from deteriorating due to oxygen in the fresh air discharged from the idle cylinders 1 to 3, and improves its durability. It increases it.

That is, during partial cylinder operation, a signal from the temperature sensor 21 that detects the temperature of the second catalyst 8 indicates that the temperature of the second catalyst 8 is below a set value (for example, 500° C.)! , the control circuit 15 opens the second fresh air supply valve 20 interposed in the auxiliary passage 19#F, and supplies air to the idle cylinders 1 to 3 from the auxiliary passage 19 as well as from the fresh air supply passage 17. Introduce fresh air. On the other hand, when the temperature of the catalyst 8 exceeds the set value r, the second fresh air supply 9F20 is commanded and controlled to close according to the temperature, and the fresh air introduced from the auxiliary passage 19 is throttled. That's what I do. This reduces the supply of fresh air,
The amount i flowing into the second catalyst 8 is suppressed.

In this case, the second fresh air supply valve 20 is controlled to open and close in a range from fully open to fully closed depending on the temperature of the catalyst 8. However, during all-cylinder operation, the fresh air supply valve 18 of the fresh air supply passage 17 is maintained in a fully closed state.

Next, an example of the control circuit 15 which controls opening and closing of this second fresh air supply ff2 (l) is shown in FIG.

In the figure, reference numeral 21 denotes a t@degree sensor provided in the second catalyst 8, and its detection signal is input to the comparator 23. Comparator 23Fi,
The detection signal is compared with the signal from the set value signal generation port wI24, and if the detection signal is small, a high level signal "m1" is outputted and input to the AND circuit 25.

On the other hand, 26 is a cylinder number control circuit which outputs a high level signal @l''i during one partial cylinder operation, and inputs this i into the AND circuit 25.

Therefore, the AND circuit 25 outputs a high level signal ""1" when the S cylinder is operating and the temperature of the second catalyst 8 is below the set value.

Then, this high level signal -1'' is sent to the second fresh air supply valve 20 through the amplifier 27, and the ff2(l) is opened.

On the other hand, when the temperature of the second catalyst 8 is higher than the set value even during full cylinder operation or partial cylinder operation, K is
The output of the AND circuit 25 becomes a-level (@0'), thereby closing the second fresh air supply valve 20.

Note that the signal from the cylinder number control circuit 26 is also given to the fresh air supply valve 18 of the fresh air supply passage 17 via the amplifier 28, and the throttle valve 18 is opened and closed in accordance with the signal.

In this example, the second fresh air supply valve 20r is turned on and off depending on the temperature of the catalyst 8, but of course, as described above, the opening degree r of the supply valve 20 is controlled depending on the temperature of the catalyst 8. It is possible to control linearly.

Alternatively, the fresh air supply valve 18Q installed in the fresh air supply passage 17 may be controlled to open and close according to the temperature of the catalyst 8 without providing such a trap, the second fresh air supply 5P20, and the auxiliary passage 19Q. Good, but in this case, the fresh air supply 9P18 is VcFi fully closed during all-cylinder operation, but the minimum opening degree is selected during S-minute cylinder operation.

In this embodiment, Fi, KFi when the temperature of the second catalyst 8 is high during one partial cylinder operation, and stop @ cylinders 1 to 3.
Since the fresh air introduced into the second catalyst 8 is busy with V wave packets flowing into the second catalyst 8, the function of the catalyst 8 is prevented from deteriorating due to the oxygen in the incoming fresh air, and the durability is increased. You can improve your sexual performance. Therefore, it is always the first. It is possible to maintain the conversion efficiency of the second catalyst 7.8 to the best level and obtain a good exhaust gas composition.

As explained above, according to the present invention, the first catalyst and the second catalyst are installed separately from the three-way catalyst corresponding to the active cylinder and the idle cylinder, while the second catalyst During partial cylinder operation, when only fresh air is supplied to the cylinder on the idle side, if the detected temperature is higher than the set value, the supply of fresh air is reduced by 31, and the second catalyst is Since the fresh air flowing into the trap was prevented from dying, deterioration of the catalyst was prevented,
This has the effect of always providing clean exhaust gas and improving the durability of one catalyst.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a conventional example, J21V is a cross-sectional view showing an embodiment i of the present invention, and FIG. W3 is a partial circuit diagram showing an example i of the control circuit of the present invention. 2... Pause side exhaust passage, 3... Rhythm side exhaust passage, 4
... Throttle valve, 7... First catalyst, 8... Second catalyst, 9... First oxygen sensor % 10... Second oxygen sensor. 11... Inactive side intake passage, 12... Operating side port and air passage. 13... Fresh air cutoff 9P, 15... Control circuit, 17.
... Fresh air supply passage, 18... Fresh air supply valve, 19...
Auxiliary passage. 20...Second fresh air supply valve %21...Temperature sensor. Patent applicant Nissan Automatic Summer Co., Ltd.

Claims (1)

[Claims] In a multi-cylinder engine, the intake passage The exhaust passage V is divided downstream of the throttle valve corresponding to the idle side and operating side cylinders, and the exhaust passage V is also divided halfway corresponding to the idle side and operating cylinders, and a ternary pipe is installed downstream of the operating side exhaust passage. A first catalyst consisting of a catalyst and a second catalyst downstream of the confluence with the idle side exhaust passage are respectively installed;
A temperature sensor r for detecting the temperature r of this second catalyst is provided, and a fresh air cutoff 5Pi that closes when the fuel is cut off is provided at the upstream portion of the intake passage on the idle side, and an intake passage II downstream of this cutoff valve and an intake passage II upstream of the throttle valve are provided. Fresh air supply passage hairstyle kite! This fresh air supply passage r is provided with a fresh air supply valve i that opens and closes, and this fresh air supply 9
Pk The number of cylinders is controlled by rfF, which is equipped with a control circuit that opens only when the fuel is cut off, and reduces the opening degree V of the supply valve in accordance with the temperature when the temperature detected by the temperature sensor exceeds a set value. engine.