JPH022907Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a drive device for a distributor and an engine rotation sensor used to control an engine. The present invention relates to a drive device for a distributor and an engine rotation sensor in an engine.

(Prior Art) In recent years, in order to meet the demand for higher output of automobile engines, fuel injection internal combustion engines have been widely adopted as such engines.
In such a fuel-injected internal combustion engine, the amount and timing of fuel injection are controlled by the engine rotational speed and the position of the piston, that is, the crank angle. In order to detect the crank angle, an engine rotation sensor that is rotationally driven in synchronization with the rotation of the engine is usually used.

On the other hand, even in such a fuel-injected internal combustion engine, a distributor is used to control ignition timing, etc.
It is designed to rotate in synchronization with the rotation of the engine.

Since both the distributor and the engine rotation sensor are driven to rotate in synchronization with the rotation of the engine, conventionally they were integrated into one component and were driven by a single camshaft or the like. They were supposed to be driven at the same time.

(Problems to be Solved by the Invention) However, these distributors and engine rotation sensors each have different functions and purposes. Moreover, they require particularly high precision among engine control auxiliary machines. Therefore, the distributor and engine rotation sensor are often required to be adjusted individually according to their respective functions, but if they are integrated, such adjustment becomes difficult. . Then, the rotation error on one side will appear as it is on the other side. Furthermore, if a problem occurs with only one component, the entire component must be replaced.

Furthermore, such an integrated distributor and engine rotation sensor has a long axial length. Therefore, if an attempt is made to connect them directly to a camshaft or the like, the overall length of the engine becomes longer, making it difficult to mount them in a car. Therefore, they are driven via transmission members such as gears, which causes problems such as a complicated structure and increased rotational errors.

By the way, double overhead cam mechanisms are increasingly being used in automobile engines in order to improve high-speed performance. In such a double overhead cam mechanism, the intake valve and the exhaust valve are opened and closed by separate camshafts, so two camshafts are provided on the cylinder head. There is.

The present invention was developed by focusing on the structure of such a double overhead cam mechanism, and its purpose is to individually adjust or adjust the distributor and engine rotation sensor, which require particularly high rotational accuracy. To enable replacement, to have a simple structure, and to be able to rotate and drive accurately in synchronization with the rotation of the engine without increasing the overall length of the engine.

(Means for Solving the Problems) In order to achieve this object, in the present invention, in an engine equipped with a double overhead cam mechanism, a distributor and an engine rotation sensor are configured as separate units, and are connected to the ends of the two camshafts on the opposite side from the cam drive pulley attachment side through joints. Each camshaft is rotatably driven by a timing belt wrapped around the cam drive pulley and a crank pulley fixed to one end of the crankshaft. The distributor and the engine rotation sensor, whichever has a smaller allowable rotational error, is connected to the camshaft disposed on the pulling side of the timing belt.

(Function) With this configuration, the distributor and the engine rotation sensor are each driven separately by the two camshafts. Therefore, the load is not concentrated on one camshaft. Further, by making the distributor and the engine rotation sensor separate, it becomes possible to adjust them for each function. Therefore, their rotation accuracy can be improved.

Furthermore, by making the distributor and engine rotation sensor separate, even if they are placed at the end of the camshaft, an increase in the overall length of the engine can be suppressed. Therefore, they can be directly connected to the camshaft by a simple joint, and rotational errors caused by the transmission member can be prevented.

By connecting the distributor and the engine rotation sensor to the camshaft disposed on the pull side of the timing belt, the one with the smaller allowable rotation error is connected to the camshaft located on the pull side of the timing belt.
The uneven rotation is reduced. Therefore, the accuracy can be further improved.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

The figure shows one embodiment of the present invention; Fig. 1 is a cutaway front view of an engine to which the present invention is applied;
FIG. 2 is a plan view of the engine, and FIG. 3 is a front view of the engine showing the timing belt portion.

As is clear from FIGS. 1 and 2, this engine 1 is a fuel injection type internal combustion engine, and a fuel injection nozzle 3 and an intake manifold 4 are connected to an intake port 2a of a cylinder head 2.
Fuel is supplied from this fuel injection nozzle 3 under control by an appropriate control device. Further, outside air purified by an air cleaner 5 is metered and supplied from the intake manifold 4 by a throttle valve.

As shown in FIG. 1, the intake port 2a
The fuel and air supplied to the combustion chamber 7 are introduced into the combustion chamber 7 in accordance with the opening/closing operation of the intake valve 6. Further, exhaust gas is discharged from the combustion chamber 7 to the outside through the exhaust port 2b in accordance with the opening/closing operation of the exhaust valve 8. In order to operate these intake valves 6 and exhaust valves 8, two camshafts 9 and 10 are provided on the cylinder head 2 in parallel with the longitudinal direction of the engine 1. These camshafts 9 and 10 have cams 9 at positions corresponding to the intake valve 6 and the exhaust valve 8, respectively.
cams 9a, 10a are provided, and the cams 9a, 1
The rocker arms 11 and 12 are swung by the rotation of 0a, and the intake valve 6 and the exhaust valve 8 are opened and closed. The top surface of the cylinder head 2 is
It is sealed by a cylinder head cover 13.

As shown in FIG. 2, cam drive pulleys 14 and 15 are attached to one end of these camshafts 9 and 10, that is, the lower end in the figure, respectively. These cam drive pulleys 1
4 and 15, a timing belt 16 is wound around a crank pulley 17 fixed to one end of the crankshaft as shown in FIG.
It is designed to be driven in the direction of the arrow in the figure by the rotation of the crankshaft. That is, the intake valve 6
The cam drive pulley 14 of the camshaft 9 for the intake system that opens and closes the exhaust valve 8 is arranged on the side from which the timing belt 16 is sent out by the crank pulley 17, and the cam drive pulley 15 of the camshaft 10 for the exhaust system that opens and closes the exhaust valve 8. is arranged on the side where the timing belt 16 is pulled by the crank pulley 17. The diameter of the drive pulleys 14 and 15 is twice the diameter of the crank pulley 17.
This allows each camshaft 9, 10 to rotate at one-half the speed of the crankshaft.

Returning to FIG. 2, on the end surface of the cylinder head 2 opposite to the side where the cam drive pulleys 14 and 15 are provided, a distributor 18 and an engine rotation sensor 19 are separately formed. installed. In this embodiment, the engine rotation sensor 19 is required to have a smaller allowable rotational error than the distributor 18, that is, higher accuracy is required. The distributor 18 is installed at the tip side of the intake system camshaft 9 so that their rotation axes coincide with each other, and between the drive shaft 18a and the end of the camshaft 9, an Oldham They are connected by a joint 20. Further, the engine rotation sensor 19 is installed on the tip side of the exhaust system camshaft 10 so that their rotational axes coincide with each other, and the drive shaft 19
A and the camshaft 10 are similarly connected by an Oldham joint 21. Mounting plate 18b of distributor 18, mounting plate 19b of engine rotation sensor 19, and cylinder head 2
There are O-rings 22 and 23 between the end faces of the
are provided, and their drive shafts 18a, 19
The shaft hole of a is sealed from the outside.

In such an engine 1, when the crankshaft rotates and the crank pulley 17 rotates in the direction of the arrow in FIG. 3, the timing belt 16 also rotates in the direction of the arrow in FIG.
4 and 15 counterclockwise at half the speed of the crankshaft. As a result, the camshafts 9, 10 are rotationally driven, and the cams 9a, 10a
The intake valve 6 and the exhaust valve 8 are opened and closed, and the distributor 18 and the engine rotation sensor 19 are rotationally driven via the Oldham joints 20 and 21. In this way, the distributor 18 and the engine rotation sensor 19 both rotate at half the rotation speed of the engine 1, and the ignition timing of each cylinder is controlled by the distributor 18. Thus, the engine speed is detected. The detection signal of the engine rotation sensor 19 is guided to a microcomputer, and the top dead center position of each piston is measured based on the signal, and a fuel injection signal is generated at a position 10 degrees before the top dead center, respectively. An optimum amount of fuel is injected from the fuel injection nozzle 3 of the fuel injection nozzle 3.

At this time, the distributor 18 and the engine rotation sensor 19 are driven to rotate while being directly connected to the camshafts 9 and 10, which rotate in precise synchronization with the crankshaft, so that their rotation accuracy is maintained at a high level. Moreover, the engine rotation sensor 19, which requires higher accuracy, is driven by the exhaust system camshaft 10, which is arranged on the pulling side of the timing belt 16. timing belt 16
On the pull side, rotational unevenness is suppressed to be smaller than on the feed side. Therefore, the engine rotation sensor 1
9 will be driven with extremely high precision.

In this way, the distributor 18 and the engine rotation sensor 19 are configured as separate bodies, and each is driven independently by the camshafts 9 and 10, which have the same rotation speed but rotate independently. Therefore, even if one of them breaks down, only that one can be replaced, and adjustments can be made easily to suit each function. In this case, since both the distributor 18 and the engine rotation sensor 19 are mounted on the cylinder head 2 at the upper part of the engine 1, which is easy to work with, such adjustment or replacement work becomes easy.

Furthermore, since the distributor 18 and the engine rotation sensor 19 are separate, the axial length of each is shorter than when they are integrated, and the width of the engine installation space is limited. If there is a camshaft 9,
It can be arranged concentrically with the rotation axis of 10. Therefore, those drive shafts 18a, 19a
Since the rotation of the camshafts 9 and 10 can be transmitted through simple joints such as the Oldham joints 20 and 21, there is no need to use complex power transmission members such as gears, reducing costs and Weight can be reduced.

Furthermore, the distributor 18 is connected by one camshaft 9, and the other camshaft 1
Since the engine rotation sensor 19 is driven by each of the camshafts 9 and 10, the load for driving them is distributed to both the camshafts 9 and 10, and smooth operation of the camshafts 9 and 10 is ensured. The precision of the distributor 18 and engine rotation sensor 19 is also further improved.

In the above embodiment, the distributor 18 is connected to the camshaft 9 for the intake system, and the engine rotation sensor 1 is connected to the camshaft 10 for the exhaust system.
9 are connected, but whether high precision is required due to the relationship between the size of the distributor 18 and engine rotation sensor 19 and the engine installation space, or whether high accuracy is required for either of these distributor 18 or engine rotation sensor 19. They can also be concatenated in reverse, for example.

Furthermore, it is obvious that various types of joints can be used in addition to the Oldham joints 20 and 21 to connect the camshafts 9 and 10 to the distributor 18 and the engine rotation sensor 19. In any case, this joint only needs to be able to transmit rotation in one direction, so it can have a simple structure.

Further, in the above description, it is assumed that the engine 1 is a fuel injection type internal combustion engine, but the present invention is not limited to this, and as long as it is equipped with a double overhead cam mechanism, it can be used as a carburetor type internal combustion engine. It can also be applied to In a carburetor type internal combustion engine, a distributor is of course necessary, but it is also necessary to detect the engine speed for fuel control during deceleration, etc. In such a case, the above embodiment is used. If configured in the same way, similar effects can be obtained.

(Effects of the invention) As is clear from the above explanation, according to the invention, the two camshafts of the double overhead cam mechanism drive the separately formed distributor and engine rotation sensor. Therefore, if a problem occurs with any of these parts, it can be replaced independently, and the replacement parts can be made inexpensive, and each can be adjusted independently. can be made to operate in accordance with each function. In addition, since each is driven to rotate independently, rotational errors in one do not affect the other, and either the distributor or the engine rotation sensor is connected to the camshaft located on the pull side of the timing belt. By concatenating or selecting accordingly,
Overall accuracy can be improved.

Furthermore, since these distributors and engine rotation sensors are connected to the end of each camshaft opposite to the side where the cam drive pulley is attached, they can be driven using simple joints. In addition, the end portions can be easily sealed using mounting plates for the distributor and engine rotation sensor. Moreover, the increase in the overall length of the engine can also be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a cutaway front view showing an embodiment of an engine equipped with a double overhead cam mechanism to which a drive device for a distributor and engine rotation sensor according to the present invention is attached, and FIG. 2 is a front view of the engine. FIG. 3 is a front view showing the timing belt portion of the engine. 1...Engine, 2...Cylinder head, 6...
...Intake valve, 8...Exhaust valve, 9...Camshaft for intake system, 10...Camshaft for exhaust system, 13...
...Cylinder head cover, 14, 15...Cam drive pulley, 16...Timing belt, 17...
Crank pulley, 18... Day distributor,
19...Engine rotation sensor, 20, 21...Oldham joint (joint).

Claims (1)

[Scope of Claim for Utility Model Registration] A cam that has an intake system camshaft that opens and closes intake valves and an exhaust system camshaft that opens and closes exhaust valves, and that these camshafts are fixed to one end of each camshaft. In an engine equipped with a double overhead cam mechanism that is rotatably driven by a timing belt wrapped around a drive pulley and a crank pulley fixed to one end of the crankshaft; A distributor and an engine rotation sensor are connected via a joint to an end of a camshaft disposed before the timing belt is pulled by a pulley, opposite to the side where the cam drive pulley is attached. Connecting the one with a smaller rotational error, and connecting the other of the distributor and engine rotation sensor to the other end of the camshaft on the opposite side to the attachment side of the cam drive pulley via a joint. A drive device for a distributor and an engine rotation sensor in an engine equipped with a double overhead cam mechanism.