JPS58150052A - Cylinder quantity controlled engine - Google Patents

Abstract

PURPOSE:To prevent deterioration of a catalytic function, by setting a catalyst in the downstream of the junction part of each exhaust passage in idle and operative sides while another catalyst in the exhaust passage in the operative side and performing full cylinder operation when temperature of the former catalyst is at least a preset value. CONSTITUTION:Exhaust passages 2, 3 are connected respectively corresponding to idle side cylinders #1-#3 and operative side cylinders #4-#6, and the first catalyst 7 consisting of a ternary catalyst in the operative side exhaust passage while the second catalyst 8 similarly in the downstream of the junction part of the both passages 2, 3 are respectively set. Temperature of this catalyst 8 is detected by a temperature sensor 13, and its detected signal is applied to a controller 14. Then in case of entering a light load range after full cylinder operation of a relatively high load is continued, when the catalyst 8 is heated by exhaust heat and reaction heat to considerably high temperature exceeding a preset value, supply of fuel to the idle side cylinders #1-#3 is not cut even in the light load range to control an engine to perform full cylinder operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a cylinder number control engine that performs a partial cylinder operation by deactivating the operating pipes of some cylinders in a light engine load range.

In general, fuel efficiency tends to improve when the engine is operated under a high load. Therefore, in a multi-cylinder engine, when the engine load is low, the fuel supply to the -s cylinder is cut and the operating pipe is stopped. In this type of engine, which the present applicant previously applied, the load on the remaining working cylinders is relatively increased by that amount, and the furnace cost in the light load range is improved as a whole.

As shown in Fig. 1, the exhaust passage 1 is connected halfway to the idle side exhaust passage 2 and the working side exhaust passage 3 corresponding to the cylinders 1 to 3 on the resting side and the cylinders 4 to 6 on the operating side. When the operating pipes of cylinders 1 to 3 are stopped in the light load range of the engine, control is performed based on the intake air amount signal from the air flow meter 11, the rotation speed signal from the ignition coil, etc. The device (not shown) is connected to cylinder #4.
The fuel injection tank (not shown) installed in the suction boat at equal pressure corresponding to 1 to 3 is kept fully closed to cut off the fuel supply, and introduced via the throttle valve 4 of @ mad passage 5. Only fresh air is supplied to the cylinders 1 to 4#3 on the inactive side. As a result, while reducing the pumping noise in the cylinders 1 to 3 on the idle side,
Partial cylinder operation is performed by operating only active cylinders 4 to 6.

By the way, in this engine, during normal operation (when all cylinders are operated), the combusted exhaust gas is emitted from each cylinder (1 to 6), but when the engine is in partial cylinder operation, the combustion gas is discharged (11) J@
Similarly, combustion gas flows from cylinders 4 to 6 to cylinder 1 on the idle side.
Fresh air is directly discharged from ~S3.

Therefore, when a three-way catalyst pipe is used as the exhaust treatment device &6, the first catalyst 7 is used to purify only the exhaust gas from the operating cylinders 4 to 6, as shown in FIG.

Mainly exhaust gas from cylinders 1 to 3 on the idle side when all cylinders are operated.
A second catalyst 8 for t-purification is separately installed downstream of the working side exhaust passage 3 and downstream of the confluence of the single-car exhaust passages 2 and 3.

Furthermore, oxygen sensors 9. l
O is installed, and its air-to-furnace ratio signal is sent to the aforementioned control device.

Then, in the active cylinders #4 to #6, the second oxygen sensor is activated during full cylinder operation and partial cylinder operation, and in the idle cylinders #4 to #3, the second oxygen sensor is activated during full cylinder operation. The injection amount of each corresponding fuel injection valve is corrected in accordance with the detection signal of the oxygen sensor 10, and each cylinder 1 to 6 is controlled to obtain a mixture at a stoichiometric air-fuel ratio.

This increases the conversion efficiency of the first and second catalysts 7.8 and the corresponding cylinders 1 to 3. The reaction tube promotes the cleaning of the exhaust gas with the exhaust gas from Steps 4 to 6.

However, in this conventional example, fresh air from the idle cylinders 1 to 3 flows into the second catalyst 8 during the S partial cylinder operation. When the temperature of the catalyst 8 is high immediately after the transition to , the function of the catalyst 8 will deteriorate significantly due to the large amount of oxygen contained in the fresh air, and if this is repeated for a long time.

There was a problem in that the durability of the catalyst 8 itself deteriorated.

This means that the fresh air supplied to the idle cylinders 1 to 3 during partial cylinder operation is transferred to the enaflow meter 1 as shown in Fig. 2.
The engine is directly led from the upstream side through the bypass passage 12, and the first catalyst 7 and the second catalyst 8 are installed in the active exhaust passage 3 and the idle exhaust passage 2 as shown in The same can be said for the nine cases.

This invention has been made by focusing on the conventional problems, and detects the temperature of a second catalyst installed downstream of the confluence of the exhaust passages on the idle side and the active side or in the exhaust passage on the idle side. Equipped with a temperature sensor.

When the temperature of this second catalyst is higher than the set value.

To provide an engine with cylinder number control aimed at solving the above problems by preventing partial cylinder operation even in a light engine load range.

The present invention will be described below with reference to the drawings. FIG. 4 is a plan configuration diagram showing an embodiment of the present invention, and FIG. 5 is a circuit diagram showing an example of a control device thereof.

In Figure 4, for cylinders ψ1 to ≠3ti, as will be described later, the simultaneous fuel supply is interrupted mainly in the light load range of the engine, and the throttle *41+-
In contrast, cylinders 4 to 6 are inactive, to which only fresh air is supplied through the cylinders, and active cylinders are continuously supplied with solvent and fresh air.

One exhaust passage connects to these cylinders 1 to 3 on the idle side and cylinders 4 #4 to 6 in operation, and is divided halfway into an exhaust passage 2 on the idle side and an exhaust passage 3 on the active side corresponding to these. Ori,
A first catalyst 7 consisting of a three-way catalyst is installed in the working side exhaust passage 3.
Similarly, a second catalyst 8 is installed downstream of the confluence of both exhaust passages 2 and 3 (or at the idle side exhaust passage 2).

The first catalyst 7 purifies the exhaust gas from the active cylinders 4 to 6, and the second catalyst 8 mainly purifies the exhaust gas from the idle cylinders 1 to 3. Next, when the second catalyst 8 is installed in the idle side exhaust passage 2, it purifies only the exhaust gas from the idle side cylinders 1 to 3.

A temperature sensor 13 is attached to the second catalyst 8 to detect the temperature of the catalyst 8, and the detection signal is sent to the control device f! Sent to 1t14.

Further, in the operating-exhaust passage 3 and the idle-side exhaust passage 2 upstream of these catalysts 7 and 8, there is a first exhaust passage that detects the oxygen concentration sound in the exhaust gas and feeds back an air-fuel ratio signal to the control device 14, respectively. A second oxygen sensor 9°10 is installed. The air-fuel ratio control of the operating expansion cylinders 4 to 6 and the stop expansion cylinders 1 to 3 is performed by the control device flj14 as described above, and the explanation thereof will be omitted.

Then, in the control device 14, first, the air flow meter 11
The intake air amount signal from the ignition coil 15 and the rotational speed signal from the ignition coil 15 are input to the fuel injection control circuit 16.

The fuel injection control circuit 16 basically calculates the fuel injection t based on these signals and outputs a fuel pulse signal.

This fuel pulse signal is sent to the fuel injection units 9Pd to 9F corresponding to the working wJ side cylinders 4 to 6 via the output amplifier 17'i-, and is also input to the AND circuit of the cylinder number determination circuits 18 and 19. .

The cylinder number determination circuit 18 determines the nozzle width of the fuel pulse signal by 1.
Due to cycle, etc., a low level signal ``0'' is output in the light 9 load area where the amount of intake air is small compared to the engine speed, and a low level signal ``1'' is output in other areas. The output signal ti20 is sent to the OR circuit.

The detection signal of the temperature sensor 13 mentioned above is sent to the comparator 21.
is input. The comparator 21 compares the detection signal tone with a reference signal of the set value generation circuit 22.

If the temperature of the second catalyst 8 is above the set value, a high level signal is "1", and if it is lower than that, a low level signal.
It outputs a "0" sound and sends it to the Mayuki OR circuit 20.

Therefore, the output Fi of the OR circuit 20 becomes a high level °1" when the temperature of the second catalyst 8 is above the set value except in the engine light load range, and when the temperature is lower than the set value in the light load range. becomes low level “0”.

Then, this signal is input to the AND circuit 19, and A
The ND circuit 19 is configured so that the output of the OR circuit 20 is at a high level “l”.
When #, the fuel pulse signal from the fuel injection control circuit 16 is output amplified! 231 to the fuel injections 9f-a-c corresponding to the deactivated cylinders 1 to 3.

This controls the opening/closing of the fuel injections 9Pa-c and d-f. In other words, the operating elevation cylinders 4-6 are constantly supplied with fuel, and the operating lift cylinders 1-3 are light. The fuel supply is cut off in the load range and when the temperature of the second catalyst 8 is lower than the set value.

An example of the configuration of the cylinder number determining circuit 18 is shown in FIG. If the width of the fuel pulse signal from the fuel injection control circuit 16 is narrower than the set pulse width of the reference value generator 25, the 24Vi comparator outputs a signal "l" at the no-i level. The comparator 26 outputs a high level signal ``1'' when the pulse period of the fuel pulse signal is shorter than the set period of the reference value generator 27.
Output.

These signals are sent to an OR circuit 29 via an AND circuit 28.
The signal is input to the inverter 30 and then commanded after being inverted.

In this example, the OR circuit 29 also includes the % solvent injection control circuit 1.
When the throttle is fully closed, a signal 11'' is input from 6. In other words, as in the light engine load range, the output of the cylinder number judgment circuit 18 is set to low level @ 1 during idle link.
”, it is possible to perform the above-mentioned solvent control.

With this configuration, the heat injection valves a-e.

During all-cylinder operation in which fuel is supplied from cylinders df to cylinders 1 to 6, the furnace exhaust gas from each cylinder 1 to 6 and the 1st.
The reaction with the second catalyst 7.8 becomes active, and clean exhaust gas can be obtained.

After that, the state shifts to a light load region, and at this time, the second catalyst 8
If the temperature is lower than the set value, the fuel supply to the idle cylinders 1 to 3 is cut off, and partial cylinder operation is performed by operating only the active expansion cylinders 4 to 6.

Therefore, the fuel efficiency is improved, and the exhaust gas from the working side extension cylinders 4 to 6 is well reacted and purified by the first catalyst 7, and the fresh air discharged from the idle side cylinders 1 to 3. There is no possibility that the purification function of the second catalyst 8 will deteriorate due to the oxygen.

In contrast, all-cylinder operation with a relatively high angle load continues,
After that, when the vehicle enters the light load range, the temperature of the second catalyst 8 becomes considerably wet due to exhaust heat and reaction heat, and exceeds the set value. Therefore, in the light load range, the fuel supply to the idle cylinders 3 to 3 is not refreshed, and they operate in the same way as the active cylinders 4 to 6. .

As a result, the heated second catalyst 8 is exposed to the idle cylinder 1.
It is possible to prevent fresh air from flowing in from the catalyst 8 to the catalyst 8, so that the function of the catalyst 8 can be maintained well and its durability can be improved.

When the operation of all cylinders continues to some extent in the light load range, the temperature of the second catalyst 8 gradually decreases, and when it becomes lower than the set value, the fuel supply to the stop expansion cylinders 1 to 3 is interrupted. After that, the engine stops for one operation and shifts to partial cylinder operation.

In this embodiment, during the trap 1 partial cylinder operation, the entire temperature of the second catalyst 8 into which fresh air flows from cylinders 1 to 3 is detected, and if the temperature of this catalyst 8 is equal to or higher than the set value, , in the light load range, all cylinders are operated without entering partial cylinder operation.

The catalyst 8 is not deteriorated by a large amount of oxygen contained in fresh air, and the purifier can always perform well, improving durability and reliability as an exhaust treatment device.

It should be noted that it is easy to apply the present invention to the engines shown in Figs. 12 and 3 of this embodiment, and similar effects can be obtained.

As explained above, according to the present invention, S minute? In a multi-cylinder engine in which only fresh air is supplied to the stop cylinder during cylinder operation, the exhaust passage is divided halfway into the idle cylinder and the working cylinder, and a three-way catalyst is connected to the working exhaust passage. At the same time, a second catalyst is installed downstream of the body stop-exhaust passage or the confluence of both exhaust passages, and a temperature sensor that detects the temperature of this second catalyst is also installed. What is the means (control device) for operating all cylinders when the temperature is above the set value? Therefore, when the second catalyst is at high temperature, there is no possibility that fresh air from the expansion cylinder will flow in and deteriorate the catalyst function, and the durability is the same and the purification efficiency is the same as the first catalyst. This has the effect that it is possible to maintain the best exhaust gas composition and always obtain a good exhaust composition.

[Brief explanation of the drawing]

Figures 1 to 3 are plan configuration diagrams of conventional devices, respectively.
5 is a plan view showing an embodiment of the present invention, FIG. 5 is a circuit diagram showing an example of the joint control device, and FIG. 6 is a partial circuit diagram showing an example of the control device. 1... Exhaust passage, 2... Pause-exhaust passage, 3...
Operation - 1 exhaust passage, 4...throttle valve, 5...@ air passage,
7... First catalyst, 8... Second catalyst, 9... First oxygen sensor. DESCRIPTION OF SYMBOLS 10... Second oxygen sensor, 11... Air flow meter, 13... Temperature sensor, 14... Control device, 1
5...Ignition coil. Patent applicant: Nissan Auto East Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A multi-cylinder system with a dormant cylinder whose fuel supply is cut off and only fresh air is supplied depending on the engine operating conditions, and a working cylinder which is constantly supplied with fuel and fresh air and continues to operate. In an engine, the exhaust passage pipe is divided halfway corresponding to the cylinder on the idle side and the cylinder on the active side, and the first catalyst consisting of a three-way catalyst is placed in the active exhaust passage in the exhaust passage on the idle side or downstream of the confluence of both exhaust passages. In addition to installing a second catalyst pipe, a temperature sensor is provided to detect the temperature of the second catalyst, and means and means are provided for operating all cylinders when the temperature detected by the sensor is higher than a set value. Features a cylinder number control engine.