JPH02185671A - Starter device of diesel engine - Google Patents

Abstract

PURPOSE:To have easy and quick starting operation of an engine by throttling the amount of suction air with a throttle valve when the engine is to be started, and thereby reducing the starting torque. CONSTITUTION:A throttle valve 6 is closed in No.1 suction stroke, so that air passes through a hole 6a in the throttle valve 6 to be supplied to a combustion chamber 3. Accordingly the amount of suction air is throttled, and no large force is required to lift a piston 2 in No.2 compression stroke. In the suction strokes after the 2nd, ignition is made already, and the throttle valve 6 is opened already, so that the amount of suction air is not throttled, and the engine revolving speed rises in the same manner as a conventional engine to cause attainment of a specified value of revolving speed. As the amount of suction air is throttled at No.1 suction stroke in this manner the torque required to lift the piston in No.2 compression stroke can be decreased effectively. Accordingly the force of pulling a rope 11 can be reduced effectively to allow even a person with minor power to perform starting operation easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a starting device for a diesel engine.

(Prior Art) In conventional diesel engines, pulp is generally not provided in the intake passage, and the amount of intake air is not throttled.

Although it has been proposed to reduce the intake air volume to reduce noise during idling or to improve ignition performance during engine startup, it has not been possible to reduce the intake air volume to an extent that effectively reduces the starting torque when starting the engine. This has never been done before.

(Problem to be Solved by the Invention) Conventionally, the amount of intake air is not throttled at the time of starting, so the starting torque is large, and manual starting, in which the engine starting rope is pulled by hand, requires strong force.

That is, conventionally, it has been thought that if the intake air amount is reduced to an extent that can effectively reduce the starting torque, the maximum temperature of the air in the combustion chamber during the compression stroke will decrease and ignition will not occur. Therefore, in the conventional method of restricting the intake air volume to improve ignition performance at startup, the engine's charging efficiency is reduced by several percent in order to give work to the intake air and increase the maximum temperature during compression by restricting the intake air volume. The intake air amount is restricted to such an extent that the starting torque can be effectively reduced, and there is no idea of reducing the intake air amount to an extent that can effectively reduce the starting torque. In addition, in conventional proposals to reduce intake air volume to reduce noise during idling, the intake air volume is considerably reduced to ensure continuous idling operation, but this conventional method is only applicable during idling. However, it does not reduce the starting torque at the time of starting. However, according to experiments conducted by the inventors of the present invention, even if the intake air volume is throttled to the extent that the starting torque can be effectively reduced, the maximum temperature during compression does not drop compared to when the intake air volume is not throttled at all. found. The present invention has been made by paying attention to this fact.

(Means for Solving the Problems) In order to solve the above problems, the diesel engine starting device of the present invention includes a throttle valve that is arranged in the intake passage of the diesel engine to limit the amount of intake air, and a throttle valve that controls the air pressure in the diaphragm chamber. a diaphragm type actuator that opens and closes the throttle valve according to changes; and an air pressure that is driven by the rope when an engine starting rope is pulled to change the air pressure in a diaphragm chamber of the diaphragm actuator so that the throttle valve closes. A changing device is provided, and a throttle flow path that communicates the diaphragm chamber of the diaphragm type actuator with the atmosphere to gradually open the throttle valve is provided, and when the engine is started, the intake air amount is throttled by the throttle valve to increase the engine starting torque. The structure is designed to reduce the

(Function) When the rope for starting the engine is pulled, the air pressure changing device is driven by the rope, the air pressure in the diaphragm chamber of the diaphragm actuator changes, the diaphragm actuator operates, and the throttle valve is closed. Since the air pressure in the diaphragm chamber of the diaphragm actuator gradually approaches atmospheric pressure via the throttle channel, the throttle valve gradually opens. When the intake air volume is reduced during the first intake stroke using the throttle valve, the amount of air in the combustion chamber is small, so
The force required to move the piston up for the next compression stroke is small. Moreover, even in this case, the maximum temperature during compression does not decrease compared to the case where the intake air amount is not throttled. (Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

FIG. 1 is a schematic diagram of a diesel engine starting device according to an embodiment of the present invention. Reference numeral 1 indicates a cylinder block, and a piston 2 is disposed inside the cylinder block 1 so as to be movable up and down.

An intake passage 4 communicates with the combustion chamber 3 within the cylinder block 1, and an intake valve 5 is disposed at the downstream end of the intake passage 4. A throttle valve 6 is arranged in the intake passage 4, and the throttle valve 6 is fixed to a rotatable shaft 7. The throttle valve 6 is formed with a hole 6a through which air passes when the valve is closed. Reference numeral 9 denotes a recoil case. A reel 10 is rotatably disposed inside the recoil case 9, and a rope 11 for starting the engine is wound around the reel 10. A handle 12 is attached to one end of the rope 11, and although not shown in the drawing, the reel 10 is biased in the direction in which the rope 11 is wound by the biasing force of a return spring. Near the exit of the rope 11 in the recoil case 9, a bellows 13, which is an example of a pneumatic pressure changing device, is arranged that is vertically expandable and retractable. The lower end of the bellows 13 is in contact with one end of a lever 14 which is curved in an arc shape and has one end projecting downward, and the rope 11 is in contact with the lower surface of one end of this lever 14 . The lever 14 is biased counterclockwise in FIG. 1 by a spring 15, and presses the rope 11 downward to form an arcuate bend. Bellows 13 is piping 16
The diaphragm 18 is in communication with the diaphragm chamber 17a of the diaphragm actuator 17 through the diaphragm actuator 17, and the diaphragm 18 is urged toward the diaphragm chamber 17a by a coil spring 19. A rod 20 is connected to the diaphragm 18. One end of a lever 22 is rotatably connected to the tip of the rod 20 by a pin 21, and the other end of the lever 22 is fixed to the shaft 7 of the throttle valve 6. A branch pipe 23 that communicates with the atmosphere branches off from the pipe 16, and a throttle channel 24 is interposed in this branch pipe 23. The other end of the lever 14 is rotatably supported by a pin 26, and the spring 15 is also supported by a pin 26. Further, on the outer surface of the recoil case 9, a substantially conical handle receiver 27 for receiving the handle 12 and a substantially conical bellows receiver 28 for preventing the bellows 13 from flying out from the recoil case 9 are attached.

Next, the operation will be explained. By holding the handle 12 and pulling the engine starting rope 11 to the left in FIG. 1, the piston 2 moves up and down, and the lever 14 rotates clockwise against the biasing force of the spring 15, causing the bellows 13 is pushed up and compressed. This allows the diaphragm actuator 1
The pressure in the diaphragm chamber 17a of No. 7 increases, and the diaphragm 18 deforms in a direction opposite to the diaphragm chamber 17a against the biasing force of the coil spring 19, pushing the rod 20 to the right. Therefore, the lever 22 rotates counterclockwise, the throttle valve 6 moves together with the lever 22, and the throttle valve 6 is fully opened as shown by the imaginary line by the start of the first intake stroke. Since the air in the pipe 16 gradually escapes to the atmosphere via the branch pipe 23 and the throttle channel 24, the pressure in the diaphragm chamber 17a gradually decreases, and after a predetermined period of time, the diaphragm 18
returns to its original state. Therefore, the throttle valve 6 also returns to its original open state by the second intake stroke. That is, the pressure in the diaphragm chamber 17a changes as shown in FIG. 2(a), and the valve opening degree of the throttle valve 6 changes as shown in FIG. 2(b).

Due to the above operation, the throttle valve 6 is closed in the first intake stroke, so air is supplied to the combustion chamber 3 through the hole 6a of the throttle valve 6. Therefore, the amount of intake air is restricted, and no large force is required to raise the piston 2 in the second compression stroke. In the second and subsequent intake strokes, the ignition has already occurred and the throttle valve 6 has already opened, so the amount of intake air is not throttled, and the engine speed increases like a conventional engine and reaches the specified rotation speed. reach a number.

Here, the intake throttling ratio (the ratio of the intake air flow passage cross-sectional area when the throttle valve 6 is fully opened and the intake air volume is not throttled to the intake air flow passage cross-sectional area when the intake air volume is throttled) and the engine The relationship between filling efficiency, maximum temperature during compression, and maximum pressure during compression is as shown in Figure 3. In other words, if the amount of intake air is throttled so that the charging efficiency is about 70% in the first intake stroke, the maximum temperature during compression will be almost the same as when the throttle valve 6 is fully open, as shown in Figure 3 (b). It can be seen that the second fuel injection reliably ignites the fuel. Further, it can be seen that the maximum pressure during compression is about 30 kg/c- as shown in FIG. 3(C), which is about 10 kg/c- lower than when the throttle valve 6 is fully open. Therefore, the first
If the intake air amount is not throttled in the second intake stroke, the rope 11 must be pulled with a very large force in the second compression stroke just before the end of pulling the starting rope 11, whereas in this embodiment If the amount of intake air is reduced so that the filling efficiency is about 70% in the first intake stroke, the force of pulling the rope 11 can be effectively reduced. Of course, ignition 111
The force for pulling the rope 11 may be further reduced by further reducing the amount of intake air to the extent possible.

In this way, since the amount of intake air is reduced in the first intake stroke, the torque required to raise the piston in the second compression stroke can be effectively reduced. Therefore, the pulling force on the rope 11 can be effectively reduced, and even a person with weak strength can easily perform the starting operation. Also, by pulling the rope 11, the throttle valve 6 is automatically closed, and the throttle valve 6 is closed.
Since the throttle valve 6 automatically and gradually opens, there is no need to separately open and close the throttle valve 6, so that the engine can be started easily and quickly.

(Another Embodiment) FIG. 4 shows another embodiment, in which the diaphragm device 31 may be used as the air pressure changing device. The diaphragm device 31 attached to the outer surface of the recoil case 9 includes a casing 32, a diaphragm 33 housed in the casing 32, and a coil spring 35 that biases the diaphragm 33 toward the diaphragm chamber 34. A rod 36 is attached to the bottom surface of the diaphragm 33.
One end of is connected. A ring 37 is fixed to the other end of the rod 36, and the rope 11 is slidably inserted through a hole 37g of the ring 37. The diameter of the hole 37a gradually increases from the center in the axial direction toward both ends.
1 and the ring 37 are brought into line contact to reduce the sliding resistance of the rope. In this embodiment, the coil spring 19 of the diaphragm actuator 17 is arranged in the diaphragm chamber 17a.

When the rope 11 is pulled, the diaphragm 33 is pulled downward through the ring 37 and the rod 36 against the biasing force of the coil spring 35, and the diaphragm chamber 34 becomes under negative pressure. As a result, the diaphragm chamber 17a of the diaphragm actuator 17 also becomes negative pressure, the rod 20 is pulled to the left, the lever 22 rotates clockwise, and the throttle valve 6 closes. Since the diaphragm chamber 17a communicates with the atmosphere through the throttle channel 24, air gradually enters the diaphragm chamber 17a through the throttle channel 24, and after the first intake stroke, the throttle valve 6 gradually opens. The valve is fully opened by the time the rope 11 is pulled.

Therefore, the same effect as the first embodiment can be obtained.

In each of the above embodiments, the throttle valve 6 is opened by the start of the second and fourth intake strokes.
The present invention is not limited to such a configuration, but may be configured such that the throttle valve 6 is kept closed for several cycles. In short, it is sufficient that the ignition is completed by the end of pulling the rope 11.

Further, in each of the above embodiments, the throttle valve 6 is provided with the hole 6a in order to supply air to the combustion chamber 3 when the throttle valve 6 is closed, but the present invention is not limited to such a configuration. For example, air may be supplied to the combustion chamber 3 when the throttle valve 6 is closed by using a breather passage that communicates the intake passage 4 and the valve arm chamber.

(Effects of the Invention) As explained above, according to the present invention, a throttle valve is provided in the intake passage of a diesel engine, and when the engine is started, the intake air amount is throttled by the throttle valve to reduce the engine starting torque. The pulling force on the starting rope can be effectively reduced, allowing even those with weak strength to perform starting work easily.

In addition, the throttle valve automatically closes by pulling the engine starting rope, and the closed throttle valve automatically gradually opens, so there is no need to separately open and close the throttle valve. Engine starting operations can be performed easily and quickly.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a diesel engine starting device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the relationship between the opening degree of the throttle valve and the pressure in the diaphragm chamber of the diaphragm actuator when starting the engine. FIG. 3 is an explanatory diagram of the relationship between the charging efficiency, the maximum temperature during compression, and the maximum pressure during compression with respect to the intake throttle ratio, and FIG. 4 is a schematic configuration diagram of a diesel engine starting device in another embodiment of the present invention. It is. 4...Intake passage, 6...Throttle valve, 11...
Rope, 13... Bellows (air pressure changing means), 17
...Diaphragm type actuator, 17a...Diaphragm chamber, 24...Restricted channel, 31...Diaphragm device (air pressure changing means) Patent applicant Yanmar Diesel Co., Ltd. 3 Dari It Fig. 2 Rope pulling overnight Rope pulling 5 peaks Fig. 4

Claims (1)

[Claims] 1. A throttle valve that is placed in the intake passage of a diesel engine to limit the amount of intake air, a diaphragm actuator that opens and closes the throttle valve based on changes in air pressure in the diaphragm chamber, and a rope that opens and closes the throttle valve when the rope for starting the engine is pulled. an air pressure changing device that is driven by the diaphragm actuator to change the air pressure in the diaphragm chamber of the diaphragm actuator so that the throttle valve closes; 1. A starting device for a diesel engine, characterized in that a throttle flow path is provided to open the valve, and when the engine is started, the intake air amount is throttled by the throttle valve to reduce engine starting torque.