JPS60535B2 - variable valve engine - Google Patents

Description

[Detailed description of the invention] The present invention relates to a variable valve engine.

An intake valve that sucks a combustible mixture into the combustion chamber of an internal combustion engine;
An exhaust valve for discharging the exhaust gas generated by combustion of the combustible air-fuel mixture in the combustion chamber, and a third valve provided as appropriate and necessary.
It is an object of the present invention to provide an engine that can optimize the volumetric efficiency, fuel consumption, etc. of the engine according to engine operating characteristics by changing the valve lift and/or valve timing of the valves. The present invention achieves this purpose by fixing a high-speed cam and a low-speed cam having different cam profiles to a camshaft that rotates in synchronization with the crankshaft of an engine, and attaching a high-speed push rod seat corresponding to these cams. and a low speed bush rod seat is formed on the rocker arm, and a high speed push rod and a low speed push rod are formed between the high speed cam and the high speed bush rod seat and between the low speed cam and the low speed push rod seat. The high-speed push rod is engaged and disengaged by an actuating device that is operated depending on whether the engine is running at high or low speed, and the low-speed push rod has a tip and a low-speed push rod receiver. A variable valve engine in which a compression spring is installed between the seats so that when the low-speed pushrod is separated from the low-speed pushrod seat, the pushrod is held by the compression spring.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, a cylinder block 1 having a cylinder bore la and a cylinder head 3 having a combustion chamber wall 3a are fixedly connected, and a piston 5 is slidably and sealed together in a cylinder bore la to form a combustion chamber 7. A piston 5 is connected to a crankshaft 11 via a connecting rod 9, and the crankshaft 11 is rotated by reciprocating movement of the piston 5. The combustion chamber 7 is connected to an intake boat 15 bored in the cylinder head 3 via an intake valve 13, and is connected to an exhaust boat 19 bored in the cylinder head 3 via an exhaust valve 17. The intake valve 13 and the exhaust valve 17 include valve bodies 13a and 17a seated on valve seats 15a and 19a provided in the cylinder head 3, and valve rods connected to the valve bodies 13a and 17a and slidably and sealed in the cylinder head 3. 13b and 17b, the valve rods 13b and 1
Compression springs 21 and 23 are installed between the rear end of cylinder head 7b and cylinder head 3 to press valve bodies 13a and 17a against valve seats 15a and 19a to seal them. Rocker shafts 25, 27
Rocker arms 29, 31 are pivotably mounted on the rocker arms 29, 31, and knockers 37, 39 are screwed onto the rocker arms 29, 31 with lock nuts 33, 36 so that the lengths thereof can be adjusted, so that the intake valves 13 and The rear end of the exhaust valve 17 is pressed to enable valve entry. Push rod seats 29b, 31b are formed at the other ends of the rocker arms 29, 31, and a cam 43 is fixed to the camshaft 41 which rotates at the time of rotation by an appropriate transmission means (not shown) to the crankshaft 11. Push rod seats 29b, 31b and cam 43 are connected to push rod 45.
, 47 and a valve lifter 49. The variable valve mechanism of the intake valve 13 will be explained with reference to FIG.

A cam 43a having two cam profiles with different valve lifts and/or valve timings on the cam 41
, 43b are fixed. Here, the cam 43a is a low-speed cam and has a small valve lift, whereas the cam 43b is a high-speed cam and has a large valve lift. On the other hand, push rod seats 29b, 29Q are formed on the rocker arm 29 corresponding to the cams, and valve lifters 49a, 49b and push rods 45a, 45b are provided between the cams 43a, 43b. Low speed push rod 45a
A projection 46 is formed at the tip of the push rod seat 29b, and a compression spring 48 is mounted between the projection 46 and the push rod seat 29b. As shown in FIG. 2, the high-speed push rod seat 29b2 has an arcuate cross-section in a plane orthogonal to the cam rotation surface, and the intermediate portion of the high-speed push rod 45b is inserted into the push rod bearing section 51 to support the bearing. By connecting the member 51 to an operating member such as an electromagnetic solenoid 53 and a fluid cylinder and activating the electromagnetic solenoid 53, the high-speed push rod 45b swings around the mounting portion of the valve lifter 490, and the high-speed push rod 45b is indicated by a solid line. As shown, it is possible to take a position where it is seated on the push rod seat 29b2 and a position where it is removed from the push rod seat 29b2, as shown by a chain line. The electromagnetic solenoid 53 is connected to a computer 55 and records engine speed a, engine load b, and engine temperature c.
When the engine characteristic exceeds a predetermined value, the high-speed push rod 45b is set to the solid line position, and when it is below the predetermined value, the high-speed push rod 45b is set to the chain line position.

The operation of the device of the present invention will be explained below.

If the engine characteristics are below a predetermined value, the high-speed push rod 45b
is in the chain line position and is removed from the push rod seat 29b2, so the low speed push rod 45a is moved to the low speed cam 43a.
and the low speed push rod seat 29 of the rocker arm 29
b, and thereby the intake valve 13 (FIG. 1) is controlled to open and close by the low-speed cam 43a. When the engine characteristics exceed a predetermined value, the electromagnetic solenoid 53 is activated to press the high-speed push rod 45b against the side surface of the rocker arm 29. When the cams 43a and 43b rotate, the base circles of both cams have the same size, so when the base circles of the cams act, the high-speed push rod 45b becomes the solid line position and the intake valve 1
3 (FIG. 1) is controlled to open and close by a high-speed cam 43b. Note that since the high-speed cam has a large valve lift, a gap is created between the low-speed push rod 45a and the low-speed push rod seat 29b, but the play between the low-speed push rod 45a and the valve lifter 49a is absorbed by the compression spring 45. Ru. As described above, the present invention switches the engine valves in multiple stages according to the engine characteristics.

As a result, the volumetric efficiency and fuel efficiency of the engine can be optimized depending on the special characteristics of the engine operation.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the present invention, and FIG. 2 is a side sectional view of the present invention device.
FIG. 7... Combustion chamber, 11... Crankshaft, 13...
...Intake valve, 17...Exhaust valve, 41.
...Camshaft, 43, 43a, 43b...Cam, 29...
...Rocker arm, 29b, 29b,, 29b2...Push rod catch, 45, 45a, 45b...Push rod. Figure 1 Figure 2

Claims (1)

[Claims] 1 A high-speed cam and a low-speed cam with different cam profiles are fixed to a camshaft that rotates in synchronization with the engine's crankshaft, and a high-speed push rod catch and a low-speed push rod catch are installed corresponding to these cams. a high-speed push rod and a low-speed push rod are provided between the high-speed cam and the high-speed push rod catch, and between the low-speed cam and the low-speed push rod catch, respectively, and the high-speed push rod The low speed push rod is engaged and disengaged by an actuating device that is operated according to high and low speeds of the engine, and a compression spring is installed between the tip of the low speed push rod and the low speed push rod catch, so that the low speed push rod is connected to the low speed push rod. A variable valve engine in which the push rod is held by a compression spring when removed from the catch.