JPS6014906Y2 - cylinder number control engine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in a cylinder number control engine that performs partial cylinder operation by suspending the 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.For this reason, in a multi-cylinder engine, when the engine load is low, the fuel supply to the negative cylinder is cut to stop operation. An engine with controlled number of cylinders was devised that relatively increases the load on the remaining active cylinders by this amount and improves overall fuel efficiency in the light load range.

By the way, in such a conventional engine, all the cylinders are configured in the same way, and the inactive cylinder, which is inactive during partial cylinder operation, and the other active cylinder, which is always activated, are configured symmetrically with each other. Common.

For example, if it is a 6-cylinder engine, everything including the compression ratio will be the same.
Three cylinders out of six cylinders configured as above are designated as inactive cylinders, and the other three cylinders symmetrical to these are designated as active cylinders.

However, in reality, if output efficiency is improved by increasing the compression ratio of the active cylinder, for example, it is possible to further improve fuel efficiency in a light load range.

However, in this case, a new problem arises in that knocking is more likely to occur in the active cylinder in a high load region.

On the other hand, with regard to knocking, it is well known that the later the ignition timing is, the more the occurrence rate of knocking can be reduced.

The present invention was developed in consideration of the conventional situation.The compression ratio of the active cylinder is set higher than that of the idle cylinder, and the ignition timing of the active cylinder is set in the high load range where knocking is more likely to occur. While retarding the ignition timing, the ignition timing of the cylinder on the idle side is also controlled independently to the optimum timing, thereby ensuring stable operation in high load ranges.
The purpose of the present invention is to obtain an engine with controlled number of cylinders that can further improve fuel efficiency in a light load region.

This will be explained below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an embodiment of the present invention.

The intake passage 1 is located downstream of the throttle valve 2, and is connected to the working cylinders A and B.
, the working side intake passage 3 connected to C, and the idle side cylinder,
It branches into a rest-side intake passage 4 that connects to E and F.

A cutoff valve 5 is interposed in the upstream part of the idle side intake passage 4, and during partial cylinder operation, this shutoff valve 5 closes to cut off the supply of fresh air to the idle side cylinders E and F. do.

On the other hand, the exhaust passage 6 also includes an active exhaust passage 7 that connects to the active cylinders A, B, and C, and an inactive cylinder E.

It branches halfway into the idle side exhaust passage 8 which connects to F.

Of these, the idle side exhaust passage 8 is connected to the idle side intake passage 4 downstream of the cutoff valve 5 via an exhaust gas recirculation passage 9.

The exhaust gas recirculation passage 9 is provided with a three-way solenoid valve 10 and an exhaust gas recirculation valve 12 that is opened and closed by a diaphragm device 11 that responds to the valve. When the operating body is inactive, the cylinders E and F on the idle side are made to inhale exhaust gas at approximately atmospheric pressure.

This reduces pumping loss in the idle cylinders, E, and F, and further improves fuel efficiency.

Furthermore, an air-fuel ratio sensor 13 and a three-way catalyst 14 for purifying exhaust gas are arranged downstream of the air-fuel ratio sensor 13 in the exhaust passage 6.

Of these, the air-fuel ratio detection signal from the sensor 13 is sent to the control circuit 1.
Sent to 5.

Then, the control circuit 15 controls the fuel injection valves a''=f corresponding to each cylinder A to F according to this air-fuel ratio signal, and feeds back the fuel injection amount so that a mixture at the stoichiometric air-fuel ratio is obtained. Control.

In addition, the control circuit 15 controls the fuel injection valves d, e, and f to always be closed during partial cylinder operation, and cuts the fuel supply to the cylinders on the inactive side, E, and F to stop their operation. , performs basic operations as a cylinder number control engine.

By the way, the compression ratios of the active cylinders A, B, and C are set to be higher than those of the idle cylinders, E, and F, in order to further improve fuel efficiency in the light load range where only these cylinders are in operation. has been done.

Therefore, the working cylinders A and B are smaller than before.

Since the output efficiency of C is improved, it is possible to further improve fuel efficiency, especially in a light load range where only these cylinders are in operation.

However, when the compression ratio is set high in this way, knocking becomes more likely to occur in the working cylinders A, B, and C as the load increases.

Therefore, in this embodiment, the ignition system is configured as shown in Fig. 2 to retard the ignition timings of the working cylinders A, B, and C as the load increases, thereby preventing the occurrence of knocking.
By independently controlling the ignition timing of the idle cylinders, E, and F at the optimum timing, engine stability is ensured in high load ranges while improving fuel efficiency in light load ranges. That's what I do.

That is, the ignition timing control unit 20 determines the optimum ignition timing for each of the operating cylinders A, B, C and the idle cylinder based on the output signal of the intake air amount sensor 21 according to the load.
Calculate E and F.

Then, after correcting the reference ignition signal obtained from the output signal of the crank angle sensor 22 using these calculated values, the operating side ignition device 2 uses the operating side ignition signal and the resting side ignition signal, respectively.
3A and the idle side ignition device 23D.

The operating side ignition device 23A includes a power transistor 24, an ignition coil 25, a distributor 26, and spark plugs 27A arranged corresponding to cylinders A, B, and C.
, 27B, 27C, etc., and constitute a so-called full transistor ignition device, and the operating side ignition signal causes
The ignition of the operating cylinders A, B, and C is delayed in response to an increase in load to prevent knocking in a high load range.

On the other hand, the idle-side ignition device 23D is configured in the same manner as the active-side ignition device 23A, and is configured to activate the idle-side cylinders A, B, and C independently of the active cylinders A, B, and F by the idle-side ignition signal.
By always igniting the cylinder at the optimum timing, the cylinder on the idle side is
, to ensure good combustion of F.

Therefore, in light load ranges where only active cylinders A, B, and C operate, in addition to improving fuel efficiency as an engine that controls the number of cylinders, the high compression ratio improves output efficiency, further improving fuel efficiency compared to conventional models. can do.

On the other hand, in the medium/high load range, when the idle cylinders A, E, and F resume operation, the active cylinders A and B resume operation.

While the occurrence of knocking is prevented by retarding the ignition timing of C, there is also an independent cylinder control system on the idle side.

By optimally controlling the ignition timing of E and F, stable operation of the entire engine can be ensured.

As explained above, according to the cylinder number control engine of the present invention, it is possible to further improve fuel efficiency in a light load range while ensuring stable operation in a high load range.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention, and FIG. 2 is a block diagram specifically showing the ignition system in the embodiment of FIG. 20...Ignition timing control unit, 21...
... Intake air amount sensor, 22 ... Crank angle sensor, 23A ... Operating side ignition device, 23D ...
...Ignition system on the rest side, A, B, C...
Working cylinder, D. Stopped cylinder. E. F...

Claims (1)

[Scope of utility model registration request] In a multi-cylinder engine that has a dormant cylinder whose fuel supply is cut and stops operating when the engine is lightly loaded, and another working cylinder which is always in operation, the compression ratio of the working cylinder is set to be higher than that of the dormant cylinder. The engine is equipped with an ignition timing control device that retards the ignition timing of the active cylinder in accordance with an increase in load, independently of the idle cylinder.