JPH0637136B2 - Power unit mounting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mounting device for supporting an engine, which is a power unit, on a base such as a vehicle body of a vehicle.

(Prior Art) Conventionally, fuel efficiency tends to be good under high load operation, so in a multi-cylinder engine, when the engine load is small, fuel supply to some cylinders is cut off and operation is suspended. A cylinder number control engine is known which performs a reduced-cylinder operation so as to relatively increase the load of the remaining operating cylinders by this amount and improve the fuel consumption in the light load region as a whole.

However, when idling, the engine vibration is greater than in other operating conditions even when operating in all cylinders.However, in the cylinder number control engine as described above, when the cylinder is cut off during idling, the engine vibration causes the number of operating cylinders to increase. It becomes even larger due to the decrease of the number of the lights, and it gives the driver discomfort. This is because, for example, in the case of a four-cylinder engine, the peak number of torque fluctuations of the engine is halved in two-cylinder operation as compared with that in four-cylinder operation, but the amplitude of the torque fluctuation becomes significantly large.

By the way, conventionally, as a mounting device of a power unit such as an engine, for example, Tokikai 58-161617
As described in Japanese Patent Publication No. JP-A-2003-187, there are upper and lower chambers that are arranged on both the left and right sides of the rotary shaft of the power unit and in which incompressible fluid is enclosed, and the legs of the power unit are connected to the partition walls of the upper and lower chambers. By providing a pair of mounts that elastically support the power unit with respect to the base, by connecting the upper chamber of the left mount and the lower chamber of the right mount, and the lower chamber of the left mount and the upper chamber of the right mount by independent conduits, respectively. It is known that a large displacement of the power unit is suppressed during sudden acceleration.

(Problems to be Solved by the Invention) However, in this conventional one, since the purpose is essentially to increase the spring constant (roll rigidity), the transmissibility of the fluctuation torque of the power unit to the base becomes large, and It is difficult to reduce noise and noise.

The present invention has an object to resist a mounting device of a power unit that can effectively reduce vibration in a specific operation range (for example, an idling range).

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a fluid chamber which is arranged on both sides of the rotating shaft of an engine and in which an incompressible fluid is sealed, and the fluid chambers. A mount that forms a part of the wall of the engine and that deforms in response to changes in the internal pressure of the fluid chamber, and that mounts the engine elastically to the base and the fluid chambers of the two mounts communicate with each other. A conduit that allows movement and associates pressure changes in both fluid chambers, elastic membrane deformation restraint means that selectively inhibits deformation of the elastic membrane of the mount, variable combustion control means that changes the combustion state of the engine, and variable A control means for receiving the combustion control signal and the engine speed signal and operating the elastic film deformation restraining means only in a specific operation range is provided.

(Operation) Therefore, for example, when the elastic membrane deformation restraining means prohibits the deformation of the elastic membrane at the time of idling where the vibration becomes large, the volume change of the fluid chamber of each mount is absorbed by the fluid moving through the conduit. , The overall spring constant is reduced and vibration is reduced.

(Example) Hereinafter, the Example of this invention is described based on drawing.

In FIG. 1, reference numeral 1 denotes a cylinder number control engine, which controls the number of cylinders to which fuel is supplied according to an operating state, and is a group of first cylinders (second and third cylinders) that are inactive during a specific operation. 1B, 1C) and a second cylinder group (first
And fourth cylinders 1A, 1D). 2 is an intake passage, a main intake passage 4 in which a throttle valve 3 is arranged,
Each cylinder 1A, 1B, 1C, 1 is branched from the main intake passage 4
It is composed of four branch intake passages 5, 6, 7, and 8 communicating with the combustion chamber D.

Branch intake passage 6, for the second and third cylinders 1B, 1C
7, shutter valves 9 and 10 are provided,
Then, the negative pressure signal S1 corresponding to the intake negative pressure from the negative pressure sensor 11 and the rotation speed signal S2 corresponding to the engine rotation speed from the rotation speed sensor 12 are used to set the intake negative pressure Pm or less and set the engine rotation speed. When it is determined by the cylinder number control circuit 13 that it is Nm or less, the actuator 14 (for example, an electromagnetic solenoid) is actuated, and the shutter valve 9,
10 is closed and the reduced cylinder operation is performed in which only the first and fourth cylinders 1A and 1D are operated. Therefore, the cylinder number control circuit 13 functions as a variable combustion control unit that changes the combustion state of the engine.

An exhaust passage 15 is branched into four branch exhaust passages communicating with the combustion chambers of the cylinders 1A, 1B, 1C and 1D.

A water temperature sensor 16 outputs a temperature signal S3 corresponding to the engine cooling water temperature to the cylinder number control circuit 13, and when the temperature signal S4 determines that the engine is cold, another signal S1, All cylinders are operated regardless of S2.

Reference numeral 17 denotes a throttle opening sensor which is linked to the throttle valve 3 and inputs a throttle opening signal S4 to the cylinder number control circuit 13 so that all cylinders are operated during acceleration.

On the other hand, the engine 1 is supported on the bottom of the engine room of the vehicle body 21 as a base. Brackets 23, 23 extending in a substantially horizontal direction are integrally provided on both right and left sides of the rotary shaft of the engine 1, i.e., the crankshaft 1a, so as to project integrally.
A pair of mounts 2 for elastically supporting the engine 1 with respect to the vehicle body 21 is provided between the brackets 23, 23 and the vehicle body 21, that is, on both sides with the crankshaft 1a of the engine 1 interposed therebetween.
4, 24 are arranged.

Each of the mounts 24 is a cylindrical member 25 fixed to the vehicle body 21 and having upper and lower surfaces opened, and rubber or the like that seals the upper opening of the cylindrical member 25 and is connected to each bracket 23 via a connecting bolt 29. And an elastic wall 26.

The lower opening of the cylindrical member 25 is closed by an elastic film 27 composed of a movable plate 27a and a thin rubber 27b joined to the outer periphery of the movable plate 27a, whereby the cylindrical member 25 and the elastic wall 26 are sealed. A closed fluid chamber 28 is formed by the elastic film 27, and an incompressible fluid (liquid) is enclosed in the fluid chamber 28. Each elastic film 27 is in the fluid chamber 2
A part of the wall of the fluid chamber 8 is formed, and is deformed according to the change of the internal pressure of the fluid chamber 28.

In addition, the cylindrical members 25, 25 of the mounts 24, 24
Each end of a conduit 30 is connected to the
By setting 0, the fluid chambers 28, 28 of both mounts 24, 24 are communicated with each other to allow the movement of fluid, and the pressure changes of both fluid chambers 28, 28 are associated.

Further, in the fluid chamber 28, the stopper plate 3 that restricts upward deformation of each elastic film 27 by a predetermined amount or more.
1 is provided in a part thereof, and communication holes 32, 32, ... Allowing the movement of the fluid are opened in a part thereof.

On the other hand, on the lower side of the elastic film 27, the outer edge portion is the mount 2
A substantially cup-shaped support plate 34 fixed to the lower end of the cylindrical member 5 of No. 4 is provided. A support hole 37 is opened in the support plate 34, and a push rod 36 is inserted into the support hole 37 so as to be vertically movable, and the movable plate 27a of the elastic film 27 can be abutted on the upper end of the push rod 36. An abutting portion 36a is formed. Push rod 36
Is in the lowered position, the distance between the contact portion 36a and the elastic film 27 is such that the stopper plate 31 and the elastic film 27 are spaced apart from each other.
It is provided so as to be equal to the distance between and.

Further, an electromagnet 38 for moving the push rod 36 upward by energization is attached to the support plate 34, and when the electromagnet 38 is not energized, the push rod 36 is in a descending position allowing deformation of the elastic film 27. On the other hand, when the electromagnet 38 is energized, the push rod 36 moves upward and pushes the elastic film 27 against the stopper plate 31 at its abutting portion 36a to reach the raised position where its deformation is prohibited. In this way, the elastic film deformation restraining means 39 for selectively inhibiting the deformation of the elastic film 27 is configured.

Further, a controller 40 is connected to each of the electromagnets 38, and the controller 40 is connected to the engine speed signal S1 from the engine speed sensor 12, the cylinder number determination signal S2 from the cylinder number control circuit 13, and the water temperature sensor 16. Temperature signal S3 and throttle opening signal S4 from the throttle opening sensor 17 are input, and when the controller 40 determines that it is idling due to the reduced cylinder operation, the electromagnet 38 is energized. Then, the push-in rod 36 is moved upward to a raised position to prohibit the deformation of the elastic film 27.

The vibration frequency characteristic of the absolute spring constant (roll rigidity) of the mounting device is as shown in FIG. That is, when the elastic membrane is constrained, in the low frequency range, the conduit 30
Since the fluid moves inside, it is approximately equal to the static spring constant K when communicating with the fluid chamber 28, and decreases as the frequency increases and reaches the minimum value at the frequency fa. When the frequency increases beyond the minimum frequency fa, the conduit 3 proportional to the square of the acceleration
Since the fluid becomes difficult to flow in the conduit 30 due to the increase of the inertial force of the fluid in 0, it increases relatively rapidly, and the non-communication spring constant (1 + N) K (N is a mount when the fluid chamber 28 is non-communication at the frequency fe. (Expansion / moving spring constant ratio of the elastic wall 26 in 24). It further increases beyond the above-mentioned frequency fe and reaches the maximum value at the natural frequency fn of the fluid in the conduit 30. In a frequency range higher than the natural frequency fn, the frequency decreases with an increase in the frequency, and gradually approaches the specific communication spring constant (1 + N) K in a state where the fluid does not flow in the conduit 30. The diameter of the conduit 30, the fluid viscosity, etc. are established in advance so that the vibration frequency fa corresponding to the minimum spring constant of the mounting device becomes substantially equal to the idle rotation speed due to the reduced cylinder operation. As a result, the maximum effective range in the vibration frequency characteristic of the absolute spring constant of the mounting device is generated in the frequency range during idling due to the reduced cylinder operation.

With the above configuration, when idling due to the reduced cylinder operation, the electromagnet 38 is energized by the controller 40, the push rod 36 moves upward to a raised position, and the elastic film 27 is pressed against the stopper plate 31 to deform it. Is prohibited. Therefore, as the engine 2 vibrates, the fluid in both fluid chambers 28, 28 moves through the conduit 30, and the change in volume of the fluid chamber 28 is absorbed by the fluid movement, which is shown in FIG. The absolute spring constant can be kept extremely small by effectively utilizing the maximum effect range in the vibration frequency characteristic of the spring constant. Therefore, the transmission rate of the vibration of the engine 1 to the vehicle body 21 is reduced, and the vehicle body 21
Vibration and noise can be mitigated.

During other operations, the electromagnets 38 are kept in a non-energized state by the control of the controller, the push rod 36 of the engine 1 is held at a lowered position slightly apart from the elastic film 27, and the elastic film 27 can be freely deformed. Become. Therefore, due to the vibration, the fluid does not move through the conduit 30 between the fluid chambers 28, 28, and instead each elastic film 17 is deformed to absorb the volume change of the fluid chamber 28.
As a result, the absolute spring constant of the mounting device is K + ΔK, which is the static spring constant K plus the film rigidity ΔK of the elastic film 27, even though the fluid chambers 28, 28 of both mounts 24, 24 are communicated by the conduit 30. Therefore, it is kept small regardless of the change of the vibration frequency, and the increase of the spring constant due to the communication effect of the conduit 30 is prevented.

(Advantages of the Invention) As described above, the present invention has mounts arranged on both sides of a rotary shaft of an engine, which is a power unit, so that fluid chambers of the mounts are communicated with each other by conduits, and a wall of each fluid chamber is connected. Part of the elastic film is formed by elastic film, and the elastic film deformation is selectively prohibited by the elastic film deformation restraint means, and the elastic film is deformed only in a specific operating range according to the variable combustion control signal and the engine speed signal. Since the restraint means is activated, the elastic membrane deformation restraint means inhibits the deformation of the elastic membrane to reduce the spring constant, for example, at the time of idling when the vibration becomes large, thereby transmitting the vibration to the base. It is possible to reduce the rate and effectively reduce the vibration and noise of the base. In particular, since the control is performed not only according to the engine rotation signal but also according to the variable combustion control signal, it is possible to reduce the vibration in accordance with the change in the vibration state accompanying the change in the combustion state.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of a mounting device for a power unit, and FIG. 2 is an explanatory diagram showing vibration frequency characteristics of an absolute spring constant of the mounting device for a power unit. 1 ... Cylinder number control engine, 1a ... Crank shaft, 24
...... Mount, 27 …… Elastic membrane, 28 …… Fluid chamber, 30
...... Conduit, 39 …… Elastic membrane deformation restraint means, 40 …… Controller

Claims (1)

[Claims] 1. A fluid chamber, which is disposed on both sides of a rotary shaft of an engine and in which incompressible fluid is sealed, and a part of a wall of each fluid chamber, which are deformed according to a change in internal pressure of the fluid chamber. A mount having an elastic membrane that elastically supports the engine with respect to the base, a conduit that connects the fluid chambers of both mounts to allow the movement of fluid and associates the pressure change of both fluid chambers, Elastic membrane deformation restraint means for selectively inhibiting deformation of the elastic membrane, variable combustion control means for changing the combustion state of the engine, and variable combustion control signal and engine speed signal are input to the elastic membrane deformation restraint means. A mounting device for a power unit, comprising: a control unit that operates only in a specific operation range.