JPH03271530A - Variable mechanism of compression ratio in internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the starting characteristic by providing constitution such that compression ratio is variably controlled by using an oil hydraulic motor to move a crankshaft and a bearing. CONSTITUTION:A stroke position of a piston 1 is also moved by the equal amount by moving a crank 4 in a vertical direction without fixation. In this way, compression ratio is variably controlled by changing the clearance volume (combustion chamber volume). That is, in order to lower a crankshaft section 5 (lower compression ratio) in a vertically variable device of a crankshaft, a movable bearing is lowered by increasing a pressure of oil in hydraulic pistons 7a, higher than hydraulic pistons 7c, d with the hydraulic pistons 7a to 7d being made to be independent. A pressure of oil in the hydraulic pistons 7c, d is increased higher than the pressure of oil in the hydraulic pistons 7a, b reversely in the case of raising the crankshaft.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a measure for varying the compression ratio of a reciprocating engine when the engine is stopped and in operation.

(Prior Art) Conventionally, the compression ratio was constant. Therefore, if the compression ratio is set high, horsepower and torque will increase to a certain extent. However, overload or high boost pressure from a supercharger can increase the occurrence of knock, so knocking can be suppressed by delaying the ignition timing. As a result, the explosion stroke occurred after the top dead center, resulting in a drop in output.

(Problems to be Solved by the Invention) Therefore, the compression ratio was lowered or, in the case of a gasoline engine, a gasoline engine with a high octane number was used to improve knock resistance. These factors led to deterioration in fuel efficiency and were not economical. Therefore, even when the engine is in operation, by varying the compression ratio and adjusting it to the optimum compression ratio under the circumstances, low fuel consumption and high output are possible. It also improves the ability to increase the capacity of the cell starter by setting a high compression ratio. Further, by setting a high compression ratio at the time of starting, the starting characteristics can also be improved.

(Means for Solving the Problems) In order to solve the above problems, in claim (1), the crankshaft is not fixed, but is moved up and down via a bearing using a hydraulic motor. This bearing is
Provide a slider so that it only moves in the up and down direction, so that it does not vibrate. The crankshaft is then moved by sandwiching the bearing between the hydraulic pistons. and,
The cylinder liner is made long enough to allow the above movement. This mechanism is installed in each crank journal and fixed to the cylinder block.

In claim (2), gears are provided on the crankshaft and the output shaft, respectively, and power is transmitted using an intermediate gear. This intermediate gear is fixed using two arms, each arm having an intermediate gear shaft at one end, a crankshaft at the other end, and an output shaft via a bearing.

(Operation) Therefore, in the present invention, with the above configuration, the stroke and bore of the engine remain unchanged, and only the clearance volume is changed.

This results in a change in the compression ratio. the result,
The compression ratio can be varied even while the engine is in operation. Thereby, the capacity of the cell scooter can be reduced by adjusting the compression ratio to a low value at the time of starting. Furthermore, by setting a high compression ratio, starting characteristics can be improved. Therefore, by setting a high compression ratio after inertia has been established, the starting characteristics can be further improved. Furthermore, during operation, excellent thermal efficiency can be achieved by increasing the compression ratio to the point where knocking occurs. In particular, in a supercharged engine, high output can be generated by supplementing low-speed torque and adjusting the compression ratio to a low value in a high-speed range where supercharging pressure increases. Alternatively, engine braking can also be increased. Furthermore, since the bearing is supported by hydraulic pressure, vibration can also be reduced.

(Example) Hereinafter, the present invention will be explained based on examples.

FIG. 1 shows a principle diagram of the present invention. 1 is a piston, 2 is a cylinder, 3 is a connecting rod, and 4 is a crank. By moving the crank 4 vertically without fixing it, the stroke position of the piston 1 also moves by the same distance. As a result, the clearance volume (combustion chamber volume) changes. As a result, the compression ratio is varied.

To give an example of calculation, bore is 60mm, stroke is 70mm
, when the clearance volume is 12cc (maximum compression ratio is 12), in order to vary the compression ratio from 7 to 12, crank 1
The variable amount (direction to increase the gap volume) is 5.3 m.
m is fine.

FIG. 2 shows a sectional view of an embodiment of the crankshaft vertically variable device according to claim (1) of the present invention.

5 is the cross section of the crankshaft, 6 is the movable bearing, 78-7
d is a hydraulic piston, and 8a to 8d are oil passages.

9 is a movable bearing, a fixing device, 10 is a fixing bolt, 11 is a cylinder block, and in order to lower the crankshaft cross section 5 (lower the compression ratio), hydraulic pistons 7a to 7d are used.
By making the hydraulic pistons 7a and 7b independent and raising the oil pressure of the hydraulic pistons 7a and 7b more than the hydraulic pistons 7c and d, the movable bearing can be lowered.

Conversely, when lowering the pressure, the oil pressure of the hydraulic pistons 7c, d may be raised higher than the oil pressure of the hydraulic pistons 7a, b. This is a hydraulic piston 7 a = d across a movable bearing 6
This is a hydraulic motor.

The hydraulic pressure of the hydraulic pistons 78 to 7d is independent of the engine! Since the load on the crankshaft is not constant during the operation, it is desirable to use a potentiometer to control the movable bearing 6 and independently control the oil pressure.

Furthermore, even when this mechanism is provided in each crank jar, it is desirable to control the oil pressure independently in view of the load.

Furthermore, in order to reduce vibrations and move the movable bearing 6 smoothly in a multi-cylinder engine, a bearing beam can be used to connect the movable bearings. A movable bearing 6 is integrated with other movable bearings. Furthermore, in order to provide an oil hole in the crank bottle for lubrication, an oil passage may be provided in the bearing beam and lubricant oil may be supplied to each crank journal in the conventional manner. Then, lubricating oil may be supplied to the oil passage of the bearing beam using a flexible pipe.

FIG. 3 shows a front view of an embodiment according to claim (2) of the present invention.

12 is an output shaft, 13 is an output shaft side gear, 14 is a crankshaft side gear, 15 is an intermediate gear, and 16a is an arm a0. FIG. 4 shows a front view of an embodiment according to claim (2) of the present invention.

16b is the arm b, and 17 is the crankshaft.

FIG. 5 shows a side view of an embodiment according to claim (2) of the present invention.

The third section is a front view seen from the output shaft 12 side, and the intermediate gear 1
5 is installed on the output shaft 12 via a bearing using an arm 16a.

Similarly to FIG. 3, FIG. 4 shows the crankshaft 17 replaced with the crankshaft 17, and is seen from the opposite side of FIG. 3. intermediate gear 15
always moves in contact with the crankshaft side gear 14 and the output shaft side gear 13 by the arms a and b, and the crankshaft side gear 14
transmits power in response to the movement of the

Figure 5 shows them viewed from the side, with the crankshaft 17
When the intermediate gear 15 moves upward, the intermediate gear 15 also moves while rotating on the crankshaft side gear 14 and the output shaft side gear 13.

As described above, eccentric movement of the output shaft 12 and the crankshaft 17 can be accommodated.

Furthermore, an arm can be added to increase the rigidity of the intermediate gear 15. When the intermediate gear 15 is formed by two gears and a shaft (the part between the shafts C) and the output shaft 12 and the crankshaft 17 (the part that passes through the gears)
and two arms are installed via bearings. Alternatively, there may be a plurality of pairs of intermediate gear 15 and arms 16a, b.

Furthermore, since these structures do not allow a cam drive or the like as in the past, this can be addressed by using a bevel gear from the crankshaft to bend the rotational force in the movable direction, and by providing a spline connection between them. Then, by using the bevel gear again to drive the camshaft, it can also be used to drive cooling fans, dynamos, power steering pumps, etc.

(Effects of the Invention) As described above, the compression ratio can be varied even when the engine is stopped and running. This allows the capacity of the cell starter to be lowered by setting a low compression ratio at the time of starting. Furthermore, by increasing the compression ratio, starting characteristics can be improved. This allows it to be applied to engines with poor startability, such as alcohol and hydrogen engines.

During operation, thermal efficiency can be improved by setting the compression ratio to be optimal under the circumstances. In particular, in a supercharged engine, it is possible to improve torque at low speeds, increase output at high speeds, and increase engine braking.

In terms of vibration, the crank bearing is floating between the hydraulic motors, which can reduce vibrations.

[Brief explanation of drawings]

FIG. 1 shows a principle diagram of the present invention. FIG. 2 shows a sectional view of an embodiment according to claim (1) of the present invention. FIG. 3 shows a front view of an embodiment according to claim (2) of the present invention as seen from the output shaft side. FIG. 4 shows a front view of an embodiment according to claim (2) of the present invention as seen from the crankshaft side. FIG. 5 shows a side view according to claim (2) of the present invention. 1 is a piston 2 is a syringe 3 is a connecting rod 4 is a crank 5 is a crankshaft cross section 6 is a movable bearing 7a is a hydraulic piston a 7b is a hydraulic piston b 7c is a hydraulic piston C 7d is a hydraulic piston d 8a is an oil passage a 8 b is an oil passage b 8c
is the oil passage C8d is the oil passage d; 9 is the movable bearing; the fixing device IO is the fixing bolt 11; the block 12 is the output shaft; Arm b 17 is the crankshaft cylinder diagram

Claims (2)

[Claims] (1) In a reciprocating engine, a mechanism that varies the compression ratio by moving the crankshaft and bearings using a hydraulic motor. (2) In claim (1), in order to connect the crankshaft side gear and the output shaft side gear with the intermediate gear, an arm is used to connect the intermediate gear shaft and the crankshaft, and the intermediate gear shaft and the output shaft on the other side. A mechanism that connects the two via bearings and transmits power.