JPH0130589Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an overspeed prevention device for an internal combustion engine.
In particular, the present invention relates to an overspeed prevention device during racing of an internal combustion engine with a carburetor.

In modern high-performance engines, if you race with a large accelerator operation that opens the carburetor's secondary throttle valve, there is a risk that the engine will instantly overrev. One possible countermeasure for this is to cut off the fuel when the allowable engine speed is exceeded, but this method requires cutting off the fuel at the tip of the main nozzle of the carburetor.
This is not practical because the structure of the vaporizer becomes complicated and costs increase.

The purpose of this invention is to provide an internal combustion engine with a carburetor,
The purpose of the present invention is to provide an over-rotation prevention device having a simple structure and low cost.

According to the present invention, a lever is fixed to the valve stem of the secondary throttle valve of the carburetor and rotates together with the secondary throttle valve, so that the rotation of the lever is controlled by a diaphragm device during engine racing. This is achieved by an overspeed prevention device for an internal combustion engine with a carburetor, which prevents the secondary throttle valve from opening by restricting its movement.

Next, embodiments of the present invention will be described in detail based on the drawings. The attached drawing is an overall view of an overspeed prevention device for an internal combustion engine with a carburetor, showing an embodiment of the present invention. In the same figure, the secondary throttle valve 1 of the carburetor
A lever 2 that rotates together with the secondary throttle valve 1 is fixed to the valve stem. The secondary throttle valve is connected to the primary throttle valve (not shown) by a well-known method such as a spring, and the secondary throttle valve starts to open only when the primary throttle valve opens to a predetermined opening degree by operating the accelerator. ing. The diaphragm device 3 has a first diaphragm chamber 5 and a second diaphragm chamber 6 partitioned by a diaphragm 4 . The first diaphragm chamber 5 communicates with the output port 9 of the electromagnetic switching valve 8 through an air passage 7, and the second diaphragm chamber 6 communicates with the atmosphere through an atmosphere communication port 10. The diaphragm 4 has a rod 11 that limits the rotation of the lever 2.
are connected. Further, a spring 12 is arranged in the first diaphragm chamber 5 to press the diaphragm 4 in the direction in which the rod 11 protrudes. The electromagnetic switching valve 8 connects the negative pressure input port 15 and the output port 9 when the electromagnetic coil 14 is energized, and connects the atmospheric input port 13 when the electromagnetic coil 14 is not energized. and the output port 9 are communicated with each other. Here, the atmospheric input port 13 is open to the atmosphere, and the negative pressure input port 15 is connected via an air passage 16 to a negative pressure extraction port 17 provided in the intake manifold. 18 is a neutral switch that opens when the shift lever of a gear type transmission (not shown) is in the neutral position and closes when the shift lever is in any other position; 19,
A clutch switch (not shown) opens when the clutch is disengaged and closes when the clutch is connected, and 20 is an ignition switch. The electromagnetic coil 14 of the electromagnetic switching valve 8, the neutral switch 18, the clutch switch 19, and the ignition switch 20 are connected in series to a battery 21.

The operation of the above embodiment will be explained. When the engine can be raced, that is, when the gear transmission shift lever is in the neutral position or the clutch is disengaged, the neutral switch 18 or clutch switch 19 is open. Even if the ignition switch 20 is closed and the engine is operating, no current flows through the electromagnetic coil 14 of the electromagnetic switching valve 8, and the atmosphere introduction port 13 and the output port 9 are in communication.
Therefore, the atmosphere entering from the atmosphere input port 13 is
It is led via an air passage 7 into a first diaphragm chamber 5 of the diaphragm device 3 . Therefore, the rod 11 protrudes to the right in the figure due to the pressing force of the spring 12. Therefore, even if the driver operates the accelerator in this state and makes the engine race, the lever 2 will come into contact with the rod 11.
Secondary throttle valve 1 is not opened. In this way, the amount of air-fuel mixture supplied to the engine is limited to a small amount, and the engine does not reach overspeed. When the vehicle is running, the shift lever of the gear type transmission is in a position other than neutral and the clutch is connected, so the neutral switch 18 and clutch switch 19 are closed. Therefore, a current flows through the electromagnetic coil 14 of the electromagnetic switching valve 8, the negative pressure introduction port 15 and the output port 9 communicate with each other, and the negative pressure in the intake pipe passes through the air passages 16 and 7 to the diaphragm device 3. 1 to a diaphragm chamber 5. In this way, the intake pipe negative pressure overcomes the pressing force of the spring 12 and pulls the diaphragm 4 toward the left in the figure, so the rod 11 does not restrict the rotation of the lever 2. The secondary throttle valve 1 can be opened.

As described above, according to the overspeed prevention device for an internal combustion engine with a carburetor according to the present invention, during racing,
Since it prevents the secondary throttle valve from opening and limits the amount of air-fuel mixture supplied to the engine, it has the effect of preventing over-speeding of the engine during racing with an inexpensive and relatively simple device. .

[Brief explanation of drawings]

The attached drawing shows an overall view of an overspeed prevention device for an internal combustion engine with a carburetor according to the present invention. 1... Secondary throttle valve, 2... Lever, 3... Diaphragm device, 8... Solenoid switching valve, 18... Neutral switch, 19... Clutch switch, 20... Ignition switch.

Claims (1)

[Scope of utility model registration request] a lever fixed to the valve shaft of the secondary throttle valve of the carburetor and rotating together with the secondary throttle valve; and a first lever defined by a diaphragm.
a diaphragm chamber and a second diaphragm chamber, and the first diaphragm chamber is filled with air or
Negative pressure is introduced into the intake pipe, atmospheric air is constantly introduced into the second diaphragm chamber, and a rod is connected to the diaphragm to limit rotation of the lever;
A spring is disposed in the first diaphragm chamber to press the diaphragm in a direction in which the rod protrudes, and when atmospheric air is introduced into the first diaphragm chamber, the rod protrudes due to the pressing force of the spring. A diaphragm device that limits the rotation of the lever in the direction in which the secondary throttle valve opens, and when electricity is applied to the electromagnetic coil, introduces intake pipe negative pressure into a first diaphragm chamber of the diaphragm device; When the electromagnetic coil is not energized, the electromagnetic switching valve that introduces atmospheric air into the first diaphragm chamber opens when the shift lever of the gear type transmission is in the neutral position, and opens when the shift lever is in the neutral position. a neutral switch that closes when the clutch is disengaged, and a clutch switch that opens when the clutch is disengaged and closes when the clutch is engaged; An overspeed prevention device for an internal combustion engine with a carburetor, characterized in that a switch is connected in series with a battery and an ignition switch.