JPS59215933A - Cylinder number control engine - Google Patents

Abstract

PURPOSE:To obtain excellent vibration suppression effects over the whole area of a partial cylinder operation by opening only suction valves of part of resting cylinders near the bottom dead point and opening only exhaust valves of other cylinders at the bottom dead point during the partial cylinder operation. CONSTITUTION:In a cylinder number control engine with #2, #3 cylinders resting during a partial cylinder operation of a 4-cylinder engine, locker arms 11, 12; 11', 12' for driving suction/exhaust valves of #2, #3 cylinders are switched to an operation position or a rest position via the action of individual oil pressure actuators 13, 14; 13', 14'. The oil pressure actuators 13-14' are driven and controlled via the oil pressure fed or discharged through a direction transfer valve 7. Shapes of rest cams 1e, 1f, 1e', 1f' are formed so that suction valves of #2 cylinder side are opened only near the bottom dead point and exhaust valve are fully closed; and suction valves of #3 cylinder side are kept fully closed and exhaust valves are opened only near the bottom dead point during the partial cylinder operation.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is an improvement of a cylinder number control engine in which the operation of some cylinders is suspended in a predetermined operating range such as a light load in a multi-cylinder engine to perform partial cylinder operation. Regarding.

BACKGROUND TECHNOLOGY In general, when an internal combustion engine is operated under a high load, the fuel consumption rate tends to improve. It is considered that the cylinder number control engine is designed to relatively increase the load on the remaining active cylinders by that amount, thereby improving overall fuel efficiency in the light load range (see the patent application previously filed by the applicant). 50-28770 etc.). Here, the most common means of deactivating some cylinders are to stop the supply of fuel and to restrict the opening of the intake and exhaust valves.
According to the latter, while the intake air trapped in the cylinder is repeatedly compressed and expanded, it causes blow piping to the crankcase side, which gradually reduces the pressure inside the cylinder on the idle side, significantly impairing the smoothness of rotation. This causes a problem (see Fig. 2; Fig. 1 shows changes in cylinder pressure in each cylinder during normal four-cylinder operation).

In order to solve this problem, the same applicant has proposed that the intake or exhaust valves be slightly opened near bottom dead center when at rest to constantly replenish intake or exhaust air into the at-rest cylinders (
Patent application No. 57-1.15002.

(Japanese Patent Application No. 57-62124, Japanese Patent Application No. 57-68132).

Among these methods, in the method of fully closing the exhaust valve of the inactive cylinder and slightly closing the intake valve near bottom dead center, as shown in Figure 2, the torque changes due to the overlap of the pressure peaks of the two inactive cylinders. The contribution to this is doubled, and it changes in response to and counteracts changes in the intake pressure of the active cylinder, so it has good characteristics: it is small at low loads, and the peak pressure increases as the load increases. This is as already stated in each application specification 1 above.

However, according to the results of subsequent studies, in order to compete with the operating cylinders, the peak pressure of the idle cylinders should be set to a higher value than the state in which combustion is not performed at the same filling rate as the operating cylinders (peak pressure during motoring). It is clear that there are points. That is, although the above method has good characteristics, the peak pressure is always insufficient (Fig. 7 (B)). On the other hand, in a system in which only the exhaust valve of the idle cylinder is opened and the intake valve is fully closed, the pressure introduced is always the exhaust pressure, which is close to atmospheric pressure (but when the two cylinders are combined, the load is relatively low). It is good when it is large, but when the load is low such as during idle link, the composite peak pressure of the idle cylinder becomes too large relative to the combustion pressure of the operating cylinder, and the imaging increases on the contrary. A method has also been proposed in which exhaust gas is introduced into only one cylinder, and the intake and exhaust valves of the other cylinder are fully closed (Japanese Patent Application No. 1983-68132).

In this case, the pressure in each cylinder has the characteristics shown in Figure 3,
Although it is relatively good under low load, the resultant peak pressure of the idle cylinders is still slightly insufficient, and as the load increases, the deficiency of the composite peak pressure of the idle cylinders increases, and the vibration suppression effect is no longer sufficient (No. 7 (See figure (B)).

As described above, in both of these two systems, the peak pressure level was insufficient over the entire operating range in which partial operation was performed, and a sufficient vibration suppressing effect was not obtained.

〈Purpose of the Invention〉The present invention has been made in view of the above-mentioned conventional problems, and it is possible to combine the deactivated cylinders in the entire operating range by performing different intake/exhaust valve opening/closing control for a plurality of deactivated cylinders during single-cylinder operation. It is an object of the present invention to provide a cylinder number control engine that can control peak pressure to a value close to a required value that counteracts the combustion pressure of operating cylinders, thereby achieving a high vibration suppression effect.

<Configuration of the Invention> For this reason, the present invention maintains the exhaust valves of some dormant cylinders closed and opens the intake valves near bottom dead center during partial cylinder operation, and closes the intake valves of other dormant cylinders. The structure is provided with means for controlling the intake and exhaust valves so as to maintain the intake and exhaust valves at the same time as opening the exhaust valves near the first dead center.

Embodiment FIG. 4 shows an example in which the present invention is applied to a cylinder number control engine in which the #2 cylinder and the #3 cylinder can be switched to operation or deactivation according to operating conditions in a four-cylinder engine. In the figure,
An oil pump 2 that is driven up and down by a cam 1a formed on a camshaft 1 draws oil from an oil gear through a check valve 3, and the oil is passed through a check valve 4 to a hydraulic chamber 5a of an accumulator 5 and to a pilot valve 60 input side boat. P. , are supplied to the input boat P1 of the directional control valve 7 and the hydraulic chamber 8a of the timing lifter 8, respectively. now,
Intake valve9. 4#2 cylinder with exhaust valve 10 and intake valve 9'
When the #3 cylinder equipped with the exhaust valve 10' is in operation, the directional control valve 7 is set to the position shown in the figure, and the intake and Hydraulic actuators 13.14 and hydraulic actuators 13' and 14' that respectively hold the exhaust valve driving rocker arms 11.12 and the intake/exhaust valve driving rocker arms 11' and 12' of the J13 cylinder from both sides. Hydraulic chamber 13a of actuator 13, 13'
, 13a', the oil in the hydraulic chambers 14a, 14a' of the other hydraulic actuator 14. 15 and is returned to the oil tank 16. Therefore, the hydraulic actuator 13
, 13' move to the left in the figure and to the right in the figure, respectively, and the rocker arm 11 for the intake/loss valve is moved.
．． 12, 11', and 12' are respectively set at the positions shown. In this state, these rocker arms 11
．． 12, 11', and 12' are operating cams 1c formed on the camshaft 1.

1d, 1c', 1d' and driven;
#2゜#3 cylinder, that is, all cylinders should be operated.

Here, the pilot valve 6 is connected to the chamber a via the output boat A1 of the directional control valve 7 and the orifice 17.

Similarly, the hydraulic pressure guided to the output side boat B1 and the orifice 18 enter the chamber. Since the hydraulic pressure is larger than the hydraulic pressure applied to vc4, the pilot valve 6 is set to a position where the valve body moves to the right as shown in the figure, and in order to apply hydraulic pressure to the chamber b1 of the directional control valve 7 accordingly, the directional control valve 7 It tries to move to the left in the figure, but in this state, the left groove 7 of the pair of grooves 7a and 7b formed in the directional control valve 7
This is prevented by a stopper 19 that engages with a. The stopper 19 is rotatably supported by a support shaft 20, and one end is supported by a spring (not shown) in a direction to engage the grooves 7a and 7b.
The other end is engaged with a transmission lever 23, which will be described later.

Changes in operating conditions from this state 1. For example, when a decrease in load is detected, a control circuit (not shown) moves the electromagnetic directional control valve 21 to the left in the figure. As a result, the chambers a2 on both sides of the hydraulic clutch 220. The hydraulic pressure guided to b2 is switched, the high pressure side hydraulic pressure is guided to chamber b2, and the piston 22a and the transmission lever 23 pivotally supported by the piston 22a move to the left in the figure, and the output lot of the transmission lever 23 and timing lifter 8 is changed. 8
c becomes engageable.

On the other hand, in the timing lifter 8, the piston 8b and the output iron 8C reciprocate in response to the discharge pressure of the oil pump 2. Specifically, the timing at which the normal lift of the intake valve 90 of the #2 cylinder ends (or the timing at which the normal lift of the intake valve 9' of the #3 cylinder ends), which is switched between operation and rest by setting the phase of the cam 1a. ), output lot 8C stands out.

Therefore, at this timing after the transmission lever 23 completes its movement, the output rod 8C of the timing lifter 8 rotates the stopper 19 via the transmission lever 23, thereby releasing the engagement between the stopper 19 and the groove 7a. Stopper 1
9 is released, the directional control valve 7 is switched and moved to the left in the figure by the signal hydraulic pressure from the pilot valve 6. When the directional control valve 7 is switched, the inlet Ill boat Pl and the output 11j baud) Bl are switched so that the return side baud) Rt and the output side boat Al are communicated with each other, so that the hydraulic pressure on the normal pressure side or the hydraulic clutch 220 chamber is switched. Be guided by a2. As a result, the transmission lever 23 is moved to the right in the figure together with the piston 22a and returned, and the timing lifter 8 is disengaged from the output rond 8c. It is locked in the state where it is engaged with the groove 7b on the right side in the figure.

When the directional control valve 7 is switched, the hydraulic pressure from the hydraulic pressure amount 5a of the accumulator 5 is applied to the hydraulic actuators 14, 14 at a predetermined timing via the output side port Bx of the directional control valve 7 and the oil front 1b (9). '
is supplied to the hydraulic chambers 14a, 14a' of the hydraulic actuators 13, 13'.
The oil inside is sent to the oil tank 16 via the return boat R+.
will be returned to. Here, both the intake valves 9, 9' and the exhaust valves 10, 10' are connected to the rocker arms 11.12 and 11.
', 12' and operating cams 1c, 1d and 1c'.

1 d', the plungers of the hydraulic actuators 14 and 14' move to the right in the figure and to the left in the figure, respectively, due to the hydraulic pressure supplied to the hydraulic chambers 14a and 14a', and the rocker arm 11.1
2, 11' and 12' are moved in the same direction to engage with the deactivation cams 1e, 1f and 1e', 1f', thereby deactivating the operation of these cylinders #2 and #3. Due to the reversal of the oil pressure, the high pressure side oil pressure flows through the orifice 18 to the pilot valve 60 chamber. After the switching of the directional control valve 7 is completed, the valve body moves to the left in the figure, so that the signal hydraulic pressure from the pilot valve 6 urges the directional control valve 7 in the next switching direction. It acts on

(lO) Here, as shown in FIG. 5, the intake valve suspension cam 1e in one of the idle cylinders, for example #2 cylinder, is formed in a perfect circular shape so as to keep the intake valve 9 fully closed. The stop cam 18 for the exhaust valve is formed in the shape of a handle so as to open the exhaust valve 10 in the vicinity of the bottom dead center of the 4#2 cylinder for a period substantially symmetrical to the bottom dead center. Father, the #3 cylinder of another power? The intake valve stop cam 1e/ is formed into an elliptical shape to open the intake valve 9' near the bottom dead center of the #3 cylinder for a period approximately symmetrical to the bottom dead center. The stop cam 1f' of the exhaust valve 10' is formed in a perfect circular shape so as to keep the exhaust valve 1q fully closed. FIG. 6 shows the opening/closing characteristics of the intake and exhaust valves of the active cylinder and the idle cylinder during partial cylinder operation.

With such a configuration, the in-cylinder pressure in the idle cylinder is kept approximately constant in the #2 cylinder, as shown in FIG. 7 (q), and in the #3 cylinder.
The cylinder has a characteristic that increases with the intake pipe pressure, and the pressure characteristic obtained by combining these characteristics becomes a characteristic close to the pressure characteristic required corresponding to the combustion pressure of the operating cylinder in the engine operating range. Therefore, a good vibration suppressor section can be obtained over the entire range of partial cylinder operation, and smooth rotation can be achieved.The change in cylinder pressure of each cylinder with respect to the crank angle is shown in Fig. 8. It becomes as shown in .

Although this example was applied to a 4-cylinder engine, when applied to a 6-cylinder engine or an 8-cylinder engine, only the intake valves of some cylinders among the plurality of cylinders at rest are opened near the bottom dead center, and the other cylinders are opened at the bottom dead center. By opening only the exhaust valve near the dead center, the combined cylinder pressure can be brought as close to the required pressure value as possible.

<Effects of the Invention> As explained above, according to the present invention, in a cylinder number control engine, only the intake valves of some of the cylinders inactive during partial cylinder operation are opened near the first dead center, and other cylinders are opened near the bottom dead center. Since only the exhaust valve is opened in the vicinity, the composite cylinder pressure of these fully shut off cylinders has good characteristics that correspond to the combustion pressure of the operating cylinders, and a good photographic suppression function can be obtained over the entire range of partial cylinder operation. It has various excellent characteristics such as smooth rotation and improved durability of the engine.

(1st

[Brief explanation of the drawing]

Figure 1 is a diagram showing the change in cylinder pressure versus crank angle of each cylinder during full cylinder operation of a conventional cylinder number control engine, and Figure 2 is a graph showing the cylinder pressure change versus crank angle of each cylinder during partial cylinder operation of the same engine. Figure 3 is a diagram showing changes in internal pressure, and Figure 3 is a diagram showing changes in cylinder pressure with respect to the crank angle of each cylinder during partial cylinder operation of another type of conventional engine with number of cylinders controlled. A configuration diagram showing an example, FIG. 5 (5) is # of the same example.
FIG. 6 is a front view showing the shape of the cam for stopping the 2-cylinder cylinder; FIG. Figures (B) and (C) are diagrams showing the opening and closing characteristics of the intake and exhaust valves of the #2 and #3 cylinders during partial cylinder operation, respectively. Figure 7 (5) is a diagram showing the in-cylinder pressure characteristics when only the intake valve is opened near bottom dead center, and Figure 7 (B) is a diagram showing the cylinder pressure characteristics of the entire cylinder at rest during partial cylinder operation in the two conventional systems. A diagram showing the internal pressure characteristics (q is a diagram showing the cylinder pressure characteristics of the entire idle cylinder in the embodiment of the present invention,
FIG. 8 is a diagram showing the change in cylinder pressure with respect to the crank angle of each cylinder during partial cylinder operation in Example (13). 1...Cam shirt) 1d...Stopping cam for the intake valve of #2 cylinder 1 d'...Stopping cam for the #3 cylinder intake valve 1e...Stopping cam for the #2 cylinder intake valve Stop cam 1 e'...Stop cam for exhaust valve of #3 cylinder ・2...Oil pump 5...Accumulator 6...Pilot valve 7...Direction switching valve 8...Timing Lifter 9...Intake valve of #2 cylinder 9'...Intake valve of #3 cylinder 10...4
#2 cylinder exhaust valve 10'...#3 cylinder exhaust valve 11.11', 12, 12'...rocker arm 13
, 13', 14, 14'...Hydraulic actuator patent applicant Representative of Nichima Motors Co., Ltd. Patent attorney Fujio Sasashima

Claims (1)

[Claims] In a cylinder number control engine that performs partial cylinder operation in which operation of some and a plurality of cylinders is suspended by restricting the opening operations of intake valves and exhaust valves in a predetermined operating range, the engine is suspended during partial cylinder operation. Some of the cylinders that are inactive have their intake valves open only near bottom dead center and the exhaust valves are kept fully closed, while other cylinders that are inactive have their intake valves kept fully closed and their exhaust valves closed near bottom dead center. An engine for controlling the number of cylinders, characterized in that it is provided with an intake/exhaust valve operation control means that opens only when the cylinders are opened.