JPH0210273Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a braking device for an internal combustion engine.

Conventionally, diesel engines installed in large vehicles such as trucks and buses, as well as ships, have been equipped with a butterfly valve in the exhaust passage as a braking device for the engine, and by closing the butterfly valve, gas emissions from the passage are restricted. However, there are those that increase the pumping loss of the engine and the braking force of the engine, and those that release gas from the combustion chamber of the cylinder whose engine stroke phase is near the top dead center of the compression stroke to dissipate the energy stored as pressure. There was something that could increase the braking force of the engine.

The present invention attempts to increase the pumping loss of the engine by closing the exhaust valve during the 4-cycle exhaust. , an exhaust valve provided in an exhaust passage communicating with the combustion chamber, an exhaust valve stop device that stops the normal opening/closing operation of the exhaust valve and maintains it in a normally closed position, and an exhaust valve stop device that constitutes the exhaust valve stop device and the exhaust valve. A solenoid that opens the valve, a manual switch, an accelerator pedal interlocking switch, and a clutch pedal interlocking switch that are arranged in series between the solenoid and a power source to control the energization of the solenoid, and a solenoid that operates when the accelerator pedal is released. The gist of the present invention is to provide a braking device for an internal combustion engine, comprising a delay device that energizes the solenoid after a predetermined time delay after the accelerator pedal interlocking switch is turned on.

According to the present invention, when braking an internal combustion engine, the exhaust valve actuation control device closes the exhaust valve during the exhaust stroke, increases pumping loss in the engine, and provides a strong braking force to the engine. It has the effect of being

Furthermore, according to the present invention, a delay device is provided to activate the switch with a time delay after the accelerator pedal interlocking switch is turned on, so the exhaust valve is closed after the fuel has completely stopped, so that the fuel flows to the intake passage side. It has the effect of preventing backflow.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

Reference numeral 1 denotes a combustion chamber of a four-stroke diesel engine, which is formed by a cylinder head 3, a piston 5, and a cylinder block 7. Reference numeral 9 denotes an intake passage, which is formed in the cylinder head 3 and communicates with the combustion chamber 1. Reference numeral 11 denotes an intake valve, which is a valve body that partitions the intake passage 9 and the combustion chamber 1. The intake valve shaft 13 is omitted, and is biased into a closed state by an intake valve coil spring 14. An exhaust passage 15 is formed in the cylinder head 3 and communicates with the combustion chamber 1. An exhaust valve 17 is a valve body that partitions the exhaust passage 15 and the combustion chamber 1, has an exhaust valve shaft 19, and is biased into a closed state by an exhaust valve coil spring 16. 21 is a camshaft, which is disposed at the top of the cylinder head 3 and rotates at 1/2 the engine speed.
It has a cam part 23 that rotates together with the cam part 23. 25
is an intake side rocker arm, which is rotatably supported by an intake side rocker arm shaft (not shown) on the upper part of the cylinder head 3, and presses the intake valve shaft 13 of the intake valve 11 along the rotation of the cam portion 23 to open the intake valve. The valve 11 is opened and closed. Reference numeral 27 denotes an exhaust side rocker arm body constituting the exhaust valve stop device, which is rotatably supported by the exhaust side rocker arm shaft 29, one end abutting the cam portion 23, and the other end a plunger spring compressed. The plunger 33 pushed by the plunger 31 is slidably supported.
35 is a cylinder, inside which is a valve stop piston 3.
7 is slidably biased toward the left in FIG. 1 by a compressed piston spring 39. Reference numeral 41 denotes a stopper plate, which is connected to the valve stop piston 37 and is disposed so as to be movable in both left and right directions in FIG. It is a flat plate having a hole 37 with a diameter larger than that of the plunger 33. Reference numeral 40 denotes an oil passage, which is formed inside the exhaust side rocker arm main body 27 and in the internal axial direction of the exhaust side rocker arm shaft 29, communicates with the cylinder 35, and allows engine oil for operating the valve stop piston 37 to flow therethrough. Reference numeral 44 designates a solenoid that constitutes an exhaust valve operation control device, and is activated when a manual switch 43 for operating the engine brake, an accelerator pedal interlocking switch 45, and a clutch pedal interlocking switch 46 installed in the driver's seat are all ON, and the solenoid piston is activated. 4
2 in the upward direction in FIG. The accelerator pedal interlocking switch 45 and the clutch pedal interlocking switch 46 are turned ON when the foot is released from the pedal and the pedal is returned. Further, a delay device is provided which activates the energization after a predetermined time delay after the accelerator pedal interlocking switch 45 is turned on. Reference numeral 47 denotes an accumulator that stores compressed engine oil from an oil pump (not shown) at a constant pressure. 48 is a battery for power supply.

The operation of this embodiment with the above configuration will be explained below. When the engine brake is activated, by taking your foot off the accelerator pedal and clutch pedal,
By deactivating the accelerator and connecting the clutch, turning on the accelerator pedal interlocking switch 45, clutch pedal interlocking switch 46, and turning on the manual switch 43, a time delay is caused by the delay device. The solenoid 44 is activated, the solenoid piston 42 is moved upward in FIG. It is fed under pressure into the cylinder 35 inside the rocker arm body 27. The valve stop piston 37 is moved rightward in FIG. 1 against the piston spring 39 by the pumped engine oil, and the stopper plate 41 connected to the valve stop piston 37 is also moved rightward. When the stopper plate 41 is moved to the right, the head of the plunger 33 enters the hole 37 of the stopper plate 41, and the plunger 33 is slid into the other end of the exhaust-side rocker arm body 27, causing the exhaust The exhaust valve shaft 19 of the valve 17 cannot be pressed, and the exhaust valve 17 is maintained in a normally closed state by the exhaust valve coil spring 16.

To release the engine brake, release the accelerator pedal or clutch pedal and turn off the accelerator pedal interlock switch 45 or clutch pedal interlock switch 46, or turn off the manual switch 43 and deactivate the solenoid 44. The solenoid piston 42 returns to the position shown by the solid line in FIG. 3, and the engine oil in the cylinder 35 flows in the direction of the broken line arrow in FIG. 3 and is discharged. When the engine oil is discharged, the internal pressure of the cylinder 35 decreases, and the valve stop piston 37 moves to the left in FIG.
The exhaust valve 17 can be opened by contacting the narrow parallel portion 35 of the exhaust valve 1 .

As is clear from the above operation description, the exhaust valve 17
is maintained in a normally closed state when the engine brake is applied, and the relationship between the pressure P within the combustion chamber 1 and the volume V within the combustion chamber 1 changes as shown by the arrow in FIG. 4 during the motoring state. As shown in FIG. 4, since the exhaust valve 17 is closed during the exhaust stroke, the pump loss of the engine (the shaded area in FIG. 4) increases and a strong braking force acts on the engine.

As is clear from the above, it is possible to obtain an internal combustion engine that can obtain strong braking force at low cost without significantly modifying the conventional engine structure, since the exhaust-side Locker arm can be replaced with a Locker arm with a valve stop device. It produces the effect that can be achieved.

In the above embodiment, since the accelerator pedal interlocking switch 45 is provided, the exhaust valve is closed after the fuel has completely stopped when the engine brake of the present invention is activated, so that the fuel does not flow back into the intake passage. In addition, a delay device is provided so that the operation is performed with a time delay after the accelerator pedal interlocking switch 45 is turned on, thereby further preventing backflow.

[Brief explanation of the drawing]

Fig. 1 is an explanatory partial cross-sectional view showing an embodiment of the present invention, Fig. 2 is an explanatory plan view of a stopper plate showing an embodiment of the invention, and Fig. 3 is an explanatory diagram of an exhaust gas according to an embodiment of the invention. A partial cross-sectional explanatory diagram showing a valve operation control device,
FIG. 4 is a characteristic diagram showing the relationship between combustion chamber pressure P and combustion chamber volume V of an internal combustion engine according to an embodiment of the present invention. 11... Combustion chamber, 9... Intake passage, 11... Intake valve, 15... Exhaust passage, 17... Exhaust valve, 27
...Exhaust side rocker arm body, 44...Solenoid.

Claims (1)

[Scope of utility model registration request] In a four-stroke internal combustion engine, an intake valve provided in an intake passage communicating with the combustion chamber, an exhaust valve provided in an exhaust passage communicating with the combustion chamber, and a normally closed position by stopping the normal opening and closing operation of the exhaust valve. an exhaust valve stop device that holds the exhaust valve, a solenoid that constitutes the exhaust valve stop device and opens the exhaust valve;
A manual switch, an accelerator pedal interlocking switch, and a clutch pedal interlocking switch are arranged in series between the solenoid and the power supply to control the energization of the solenoid, and the accelerator pedal interlocking switch is turned ON when the foot is removed from the accelerator pedal. A braking device for an internal combustion engine, comprising a delay device that energizes the solenoid with a delay of a predetermined time after the state is reached.