JPS5857040A - Variable compression ratio mechanism of internal- combustion engine - Google Patents

Abstract

PURPOSE:To form compression ratio of an engine changeable in an analog state, by rotatably supporting a rotary connection part and the like of a connecting rod through eccentric bearings rotatable themselves and rotatively displacing said eccentric bearings in accordance with an operational condition of the engine. CONSTITUTION:A connecting rod 2 is connected to a piston 1 and rotatably connected to a crank pin part 3a of a crankshaft 3, and journal parts 3b of the crankshaft 3 are supported to bearing parts 5 in a cylinder block through eccentric bearings 4. The eccentric bearings 4 are formed rotatable for the bearing part 5, and a tooth 4a is notched to the peripheral surface of the bearing. While a worm gear 6 is mounted through ball bearings 7 in the bearing part 5, then said gear 6 is both meshed to the above described tooth 4a and connected to a pulse motor 8. Then the pulse motor 8 is driven and controlled through a pulse generator 9, controlled by a CPU10 in accordance with outputs of each sensor 11-13 of intake negative pressure, water temperature and speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides alO1! This invention relates to a type 0 internal pressure engine mechanism of a type 11 internal combustion engine.

In internal combustion engines such as gasoline engines and diesel engines that have reciprocating pistons, mixed gas Various variable compression ratio mechanisms have been proposed that change the compression ratio according to engine operating conditions. Conventional variable compression ratio mechanisms can be classified into two types: those in which the top of the piston is variable, and those in which the volume of the combustion chamber on the head side is varied as i=J. Here, the piston top that is variable is one that changes the compression ratio by moving the piston top up and down by weighing the piston and using hydraulic pressure to move oil in and out of the oil chamber formed inside the piston. Say, t.

What makes the volume of the combustion chamber on the head side variable?

A second piston, rotary pulp, etc. is provided in the combustion chamber on the cylinder head side and driven in synchronization with the main piston, thereby changing the volume of the combustion chamber and making the compression ratio variable.

However, in the nine conventional variable compression ratio mechanisms mentioned above, one mechanism is complicated, so it can only be applied to relatively large engines, the manufacturing cost is high, and once the mechanism specifications are determined, high compression ratio and low compression The disadvantage is that the compression ratio can only be changed in two steps, and the compression ratio cannot be changed in detail.

Purpose of the Invention: An internal combustion engine that is simple in construction, easy to apply to small engines, and capable of changing the compression ratio between a high compression ratio and a low compression ratio in an analog manner. The object of the present invention is to provide a variable compression ratio mechanism.

In the structure of the present invention, the eccentric bearing itself is installed between the crankshaft of the reciprocating internal combustion engine and the bearing part of the cylinder block, or between the small end of the connecting rod and the piston pin. Interposed so that it can rotate freely.

A co-rotating drive device is connected to this eccentric bearing, and this rotary drive device moves the eccentric bearing forward or reverse by an appropriate amount according to the operating condition of the internal combustion engine, thereby making the compression ratio of the internal combustion engine variable. It is in the ratio mechanism. and,
This variable compression ratio mechanism allows gasoline engines to:
The compression ratio is lowered during high loads to prevent knocking and reduce nitrogen oxides in exhaust gas, and the compression ratio is increased during low loads to improve thermal efficiency and improve fuel efficiency. It is possible to achieve this goal. In addition, in a diesel engine, the compression ratio can be lowered, and the pressure-to-dynamic ratio can be lowered at low speeds to increase thermal efficiency and improve fuel efficiency.

In any of these engines, by increasing the #i compression ratio at the time of starting, compression thermal insulation can be increased and startability can be improved.

An embodiment of the present invention will be described below with reference to the drawings.

First, the #1 embodiment of a pigeon loft to which the present invention is applied to a gasoline engine will be described based on Figures 1 to 4. A connecting rod (hereinafter referred to as a connecting rod) has a piston 1 attached to its small end via a piston pin (not shown), and its large end is rotatable in the crankshaft 3 (b). is connected to. Crankshaft 7) 3t; t Its journal a'b t-
, - supported by a bearing part 55.5 of the cylinder block via a center bearing 4.4.4', 5a, 5
m, 5a is eccentric bearing 4.4.4 bearing part 5.5J
Indicates @receiver cap for attaching K. The eccentric bearing 4.4.4 supports the crankshaft 3 rotatably, and the eccentric bearing 4.4.4
Fi itself.

It is rotatable relative to the bearing 55.5 of the cylinder block. - The outer peripheral surface of the center pairing 4.4.4 is respectively carved with rough teeth, and these two rotations mesh with the worm gear 6. Worm gear 6 is a ball bearing 7.7
The worm gear 6ti is rotatably supported by the worm gear 6ti, and is attached to the bearing part 5 of the cylinder prot.
It is connected to PulseMofi8. pulse motor 8t
The central control processing unit (hereinafter referred to as
It's called cpty. )10, cpuio
It is connected to the Fi intake negative pressure sensor 11, the water temperature sensor 12, and the rotation sensor 13, respectively. The intake negative pressure sensor 11 is attached to an intake pipe 15 connected to the cylinder 14 and is provided to detect intake negative pressure t.
A water temperature sensor 12 is provided at the ninth position to detect the water temperature in a water jacket 16 formed in the cylinder block, and a rotation sensor 13 is provided at the next position to detect the rotational speed of the crankshaft 3. These sensors 11 and 13 are provided to detect the operating state of the engine and are nothing but fc ton.
is connected to 0N by the ignition switch 17.
-01FF will operate. &Oh, in the picture.

Reference numeral 19 indicates an exhaust pipe, 20 indicates an intake valve, 21 indicates an exhaust valve, 22 indicates a force cover, and 23 indicates a bolt for fixing the bearing cap 5a to the bearing portion 5, respectively.

One effect will be explained below.

In a gasoline engine, first turn on the ignition switch 17 with the engine key, the engine starts cranking and the cptyio
starts operating. Then, sensors 11, 12, 13
The intake negative pressure and water temperature per revolution are continuously detected.
These detected values are input to CPU10 as electrical signals. As shown in the flowchart shown in Fig. 4, CPTJIO calculates the optimum compression ratio from the relationship between the optimum compression ratio, the rotational speed, and the water temperature, which has been studied in advance using bench data and is stored, and obtains this optimum pressure lB11+-. Calculate the rotation speed of the worm gear 6. Then, the number of pulses corresponding to this number of rotations is determined and a command is issued to the pulse generating bag fl19. In this way, according to the number of pulses output by the pulse generator 9, the pulse motor 8 rotates the corresponding number of times, and the worm gear 6 causes the eccentric bearing 4 to rotate.
．． 4.4 will be rotated by an appropriate angle. As a result, the crankshaft 3 rises by the lift r from the state shown in FIG. 1(A) to the state shown in FIG. 1(B), and the top of the piston 1 also rises. If the top of the piston 1 rises, the compression ratio increases, so the temperature of the mixed gas in the compression path rises, and the engine starts earlier. Furthermore, these processes.

Since it is electrically controlled, it is instantaneous.

Then, after the process described above, when the engine starts,
Based on the signals of each sensor 11h12.13, cp
UTO distinguishes the stored optimum compression ratios depending on the water temperature.1 For example, if the water temperature is 906C or higher, knocking is likely to occur, so it calculates to lower the compression ratio and calculates the worm gear 60 rotation speed for that purpose. In addition, when the water temperature is 9 degrees Celsius or lower, the compression ratio is calculated to increase, and the number of revolutions of the ninth worm gear 5oii is calculated. Then, the number of pulses corresponding to these rotational speeds of the worm gear 6 is determined and a command is issued to the Norculus generator 19. Then, according to this command, the pulse generator 9 outputs the appropriate number of pulses to the Norculus motor 9. Then, the worm gear 6 rotates the correct number of times, and the eccentric bearing 444
Rotate the meeting. As a result, the correct compression ratio can be obtained instantaneously, and in this way, the correct compression ratio can always be obtained as the operating conditions change. Note: The above water temperature is not limited to 90°.

Of course, it can be set arbitrarily.

A pinion gear can also be used instead of the worm gear 6.

The above discussion uses a gasoline engine as an example.

The main structure and function of diesel engines are exactly the same. The difference is the intake negative pressure sensor? The only difference is that the fuel pressure in the fuel injection timing timer is detected by a pressure sensor instead of -11.

Next, the main points regarding compression ratio control will be explained as follows. 4. Gasoline side-opening, diesel engine. At the time of starting, the compression ratio is increased in consideration of the viscosity of the oil and the consumption of the battery 18, thereby increasing the gas temperature in the cylinder on the compression path to improve ignition. In this case, the value of the compression ratio differs depending on the water temperature and rotation speed. Then, when starting the engine, in a gasoline engine, the compression ratio is lowered on the high load side to prevent knocking and reduce nitrogen oxides in the exhaust gas, and the compression ratio is increased on the low load side. This increases thermal efficiency and improves fuel efficiency.

5 and 6 show a second embodiment of the present invention, and the feature of this embodiment is that an eccentric bearing 4 is interposed between the small end of the connecting rod 2 and the piston pin U. At the point. A worm gear 6 connected to a pulse motor 8 is added to the small end of the connecting rod 2, and meshes with a bidirectional rotation formed on the outer circumferential surface of the 9-ohm gear 6#'i eccentric bearing 4. Of course, the eccentric bearing 4 is itself rotatable relative to the connecting rod 2. 24 indicates an oil inlet, and 25Fi indicates a snap ring for preventing piston pin removal. Other configurations and operations are similar to those of the first embodiment described above, and the rotation of the worm gear 6 rotates the concentric bearing 4, thereby changing the relative position of the piston 1 with respect to the connecting rod 2.

As explained above, one advantage of the compression ratio mechanism of the present invention is that the structure is simple and compact.

It is easy to apply even to small engines.

Since the compression ratio can be changed between a high compression ratio and a low compression ratio in an analog manner, it is possible to change the compression ratio very precisely.

[Brief explanation of drawings]

FIG. 1(a) is a side view of the main part of the first embodiment of the present invention in a low compression state, and FIG. 1(b) is a side view of the main part of the first embodiment of the invention in a high compression state. FIG. 2 is a sectional view schematically showing the overall configuration of the first embodiment of the present invention, FIG. 3 is a block diagram showing the general structure of the present invention, and FIG. 4 is a flow chart showing the operating state m of the present invention. FIG. 5 is a sectional view of a piston portion of a second embodiment of the present invention, and FIG. 6 is a partial sectional view of a connecting rod small end of FIG. 5. l...Fist piston. 2... Connecting rod. 3...Crankshaft. 36111111 @ crank bin section. 3b *...Journal section. 4Φ fist... eccentric bearing. 5. Self--Bearing part of cylinder block. 6. Worm gear. 8...Pulse motor. 9...Pulse generator. 10...Central control processing unit. 11...Fist intake negative pressure sensor. 12. Fist: Water temperature sensor. 13. War/rotation sensor. 17...Ignition switch. 1811...Battery. Patent applicant Toyota Motor Corporation Agent Patent attorney 1) Tsuneo Fuchi 13- Figure 1 (a) (b) Figure 2 Qo 4- Old

Claims (1)

[Scope of Claims] (1) A rotating connecting portion of a connecting rod or a rotating supporting portion of a crankshaft of a reciprocating internal combustion engine is rotatably supported by an eccentric bearing that can rotate itself, and the operating state of the internal combustion engine is A variable compression ratio mechanism for an internal combustion engine, characterized in that a rotary drive device is provided which rotates the eccentric bearing W1 by correcting or reversing the eccentric bearing by an appropriate amount in accordance with the change in the compression ratio. (2. Variable compression ratio machine #4 according to claim 1, in which the eccentric bearing is interposed between the crankshaft and the bearing portion of the cylinder block. (3) Claim 1. 1JJ, in which the eccentric bearing is interposed between the small end of the connecting rod and the piston pin. (4) Any one of claims 1 to 3. In the six-speed compression ratio mechanism described in Item 1, the rotary drive device includes a pulse motor that rotationally drives the eccentric bearing, a pulse generator that supplies pulses to the pulse motor, and a pulse generator that supplies pulses to the internal combustion engine. Central control processing bag c that outputs pulse generation commands according to the operating status of the engine
d, and a sensor that allows the central control processing unit to recognize the operating state of the internal combustion engine.