JPS5835242A - Cylinder quantity controlled engine - Google Patents

Abstract

PURPOSE:To decrease current consumption of a battery and save fuel consumption, by disconnecting an ignition circuit for idle side cylinders at partial cylinder operation and cutting off a feed of energy to spark plugs. CONSTITUTION:Ignition coils 20A, 20B and distributor units 21A, 21B are provided respectively for spark plugs a1-a3 of normally operated cylinders 1-3 and spark plugs a4-a6 of idle cylinders 4-6, while a contact 24a is interposed in a relay switch 24 provided between a battery 22 and the ignition coil 20B. At partial cylinder operation when an engine load is decreased to stop operation of the cylinders 4-6, fuel injection for the cylinders 4-6 is cut off, simultaneously the contact 24a of the relay switch 24 is opened to cut out a primary current for the ignition coil 20B, and spark ignition of the spark plugs a4-a6 is stopped. Accordingly, a consumed current of the battery 22 is decreased to half, thus fuel consumption can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder number control engine that suspends operation of some cylinders when the engine is under light load.

In general, when an engine is operated under a high load condition, fuel efficiency tends to improve. Therefore, in a multi-cylinder engine, when the engine load is low, the supply of fuel and fresh air to some cylinders is cut to stop operation. An engine with a controlled number of cylinders was devised in which the load on the remaining active cylinders was relatively increased, thereby improving overall fuel efficiency in the light load range.

Now, the applicant has made the first application for this type of engine.
As shown in the figure, the intake passage 1 is located downstream of the throttle valve 2 for cylinders #1 to ##.
It branches from the middle into an operating side intake passage 3 for cylinders #3 and a rest side intake passage 4 for cylinders #4 to #6.

Cylinders #1 to #3 are operating cylinders that are constantly supplied with fuel from the fuel injection valve 3-C attached to their intake ports, and continue to operate. Injection is stopped by the control circuit 15 in the engine light load range, and cylinders d to f are configured as idle cylinders.

A fresh air cut-off valve 5 is provided upstream of this idle-side intake passage 4 to block the inflow of fresh air when the operating body is stopped.

On the other hand, the exhaust passages also include an active side exhaust passage 7 that connects to cylinders #1 to #3, and a rest side exhaust passage 8 that connects to cylinders #4 to #6.
An air-fuel ratio sensor 13 for detecting the oxygen concentration in the exhaust gas is installed in the converging exhaust passage 6, and a three-way catalyst 14 is installed downstream of the air-fuel ratio sensor 13. 15, each cylinder well 1
- #6 is corrected so that the air-fuel mixture at approximately the stoichiometric air-fuel ratio is supplied.

An exhaust circulation passage 9 that connects to the idle side intake passage 4 downstream of the cutoff valve 5 branches from the middle of the idle side exhaust passage 8, and the exhaust gas circulation passage 9 that is connected to the idle side intake passage 4 downstream of the cutoff valve 5 branches into this circulation passage 9. An exhaust circulation valve 12 interlocked with a pressure-responsive diaphragm device 11 is interposed.

The control circuit 15 controls the amount of fuel injected from the fuel injection valves a to f based on the feedback signal described above, based on the intake air amount signal from the air flow meter 16 and the engine rotation speed signal from the crank angle sensor 17. is controlled to obtain a mixture with a stoichiometric air-fuel ratio, and based on this, the engine output fuel consumption is improved and the three-way catalyst 14
maintain the best exhaust purification efficiency.

In the engine light load range, for example, judging from the intake air amount signal, the fuel injection valves d to f of cylinder wells 4 to #6 are
The control circuit 15 outputs a command to stop the operation of the cylinder wells, simultaneously fully close the fresh air cutoff valve 5, and fully open the exhaust circulation valve 12, thereby shifting to operation using only the cylinder wells 1 to #3.

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

On the other hand, for cylinders #4 to #6 i+c on the idle side, the inflow of fresh air as well as fuel is blocked, but since the exhaust circulation passage 9 is open and communicated with, almost the entire exhaust gas discharged into the exhaust passage 8 on the idle side remains suspended. The air is drawn into the side intake passage 4, thereby maintaining the negative intake pressure of the idle cylinders #4 to #6 at approximately atmospheric pressure.

Therefore, during the intake stroke of the cylinder wells 4 to #6 on the idle side, circulating gas at approximately atmospheric pressure is sucked in, so the so-called pumping loss is kept extremely small, and the cylinder wells #4 to #6 on the idle side
While further improving fuel efficiency by reducing the work required to drive the air-fuel ratio sensor 1, it also prevents unburned air from flowing into the combined exhaust passage 6 from the idle side cylinder wells 4 to #6.
This avoids confusion in the detection function of the three-way catalyst 14 and prevents the purification efficiency of the three-way catalyst 14 from decreasing.

However, conventionally, even during partial cylinder operation in which the operation of some cylinders such as 9 is suspended, ignition energy is supplied to the ignition plugs of cylinders #4 to #6 on the idle side in the same way as during full cylinder operation. The spark ignition 1 effect was sustained.

For this reason, the electrical energy required for ignition is completely wasted, and especially when partial cylinder operation continues for a long time, the effect of saving fuel consumption will be greatly lost due to battery charging.

In order to solve this problem, it is an object of the present invention to provide a cylinder number control engine that shuts off the ignition circuit of the cylinder on the idle side during partial cylinder operation, thereby cutting off the supply of energy to the ignition plug.

Embodiments of the present invention will be described below based on the drawings.

In Fig. 2, ・alt aIs al indicates the spark plugs of cylinder wells 1 to #3 that are always activated, and “4t aSo
al are cylinder wells 4 to #6 whose operation is suspended during partial cylinder operation.
Shows a spark plug.

The ignition coils 20A, 20 for the groups 17 of these spark plugs a1 to a3 and a4 to a6 are independently connected to each other.
B, power distribution sections 21A and 21B are configured, and
The low pressure from 2 is boosted and supplied to the spark plugs a, to a6 7 in a predetermined ignition order in synchronization with engine rotation. However, the ignition coils 20B and 22 for the spark plugs a4 to a of the cylinders #4 to #6 on the idle side
A contact 24a of a relay switch 24 that cuts off one circuit during partial cylinder operation is interposed between the two.

The control circuit 15 is connected to the coil 24b of the relay switch 24.
During partial cylinder operation, an excitation current of [ij is supplied, which causes the contact 24a to open.

The other configurations are basically the same as in Figure 1, so
The first explanation will be omitted, and the operation will be explained next.

During all-cylinder operation, the contact 24a of the relay switch 24 is closed by the signal from the control N path 15, so the ignition coil 20
A and 20B are both supplied with current (-secondary current) from the battery 22, and all spark plugs a, to a6 receive high-voltage ignition current for ignition, and all cylinders #1 to #6 ignite as usual. action takes place.

In contrast, the engine load decreased and some cylinders #4 to #
During partial cylinder operation, when cylinder #4 ceases its operation, cylinder #4
- At the same time that the fuel injection to #6 is cut off, the contact 24a of the relay switch 24 opens and the ignition coil 20
Cut off the primary current to B.

For this reason, ignition is performed in the active cylinders #1 to #3 as before, but in the idle cylinders #4 to #6, high voltage ignition current is not generated from the ignition coil 20B, so the ignition plug a
Spark ignition from 4 to a6 stops.

Of course, since the cylinders on the idle side, #4 to #6, are inactive, ignition energy is not necessary, and this causes the battery 22
As described above, according to the present invention, since the supply of ignition energy to the cylinders that are inactive during partial cylinder operation is also cut off, the battery cleansing current can be reduced by half. This has the effect of reducing fuel consumption.

A brief description of the drawing,.

FIG. 1 is a schematic diagram of a conventional device, and FIG. 2 is a circuit diagram showing the main part of the present invention.

2... Throttle valve, 3... Working side intake passage, 4... Dormant side intake passage, 5... Fresh air cutoff valve, 13... Air-fuel ratio sensor, 14... Three-way catalyst, 15... control circuit, 20
A, 20B...Ignition coil, 22...Battery, 2
4...IJ L/-switch, #l to #6... cylinder, a, ~a,... spark plug.

Patent applicant: Nissan Motor Co., Ltd.

Claims (1)

[Claims] In a cylinder number control engine that includes a dormant cylinder whose operation is suspended due to fuel supply being cut off in a light engine load range, and an active cylinder which is constantly supplied with fuel, this corresponds to the dormant cylinder and the operational cylinder. 1. An engine for controlling the number of cylinders, characterized in that mutually independent ignition coils are provided, and a cutoff means is provided for cutting off the supply of primary current to the ignition coils of the cylinders on the idle side during partial cylinder operation.