JPS6111468Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a starting advance angle device.

BACKGROUND ART In diesel engines, methods for improving low-temperature startability include increasing the fuel injection amount at startup and advancing the fuel injection timing.

For example, a distribution type fuel injection pump has a start lever and a start spring inside the governor, and while the former increases the amount of fuel at startup, it is also equipped with a cold start device to increase the spring force at startup. Therefore, the differential plunger is pushed out to forcibly move the timer piston, which controls the fuel injection timing, to the advance side, thereby making it possible to achieve the latter advancement.

However, the cold start device is configured to stop its advance function when the feed pump oil pressure acting on the differential plunger becomes high and is returned by the feed oil pressure. After the engine starts, the cold start device will not be released unless the engine speed is increased from 2000rpm to 2500rpm.

Therefore, until the advance function of the cold start device is released, the engine will rotate in a state where the angle is advanced more than necessary, which is a problem in terms of exhaust emissions or noise countermeasures. When the number increases, the function is suddenly lost and the advance angle is returned to normal (retarded), which has an unfavorable feel. But, on the other hand,
When starting an engine at an outside temperature of -20℃, the engine cannot maintain stable idling speed due to the high viscosity of the engine oil, and sometimes the engine stalls. In such a situation, the cold device continues to advance the fuel injection timing, which has the advantage of stabilizing the idling rotation.

The present invention was developed in view of these points, and the advance function of the cold start device is controlled by a temperature switch that can determine the warm-up state of the engine and a key switch for starting the starter motor. It is an object of the present invention to provide a starting advance angle device that can perform the following steps.

An embodiment of the present invention shown in the drawings will be described below. In the figure, 10 is a timer, 50 is the cold start device, and these are organically combined by a control valve 57, which will be described later, and a key switch 58 and a temperature switch 61 that control it. The device is configured.

The timer 10 includes a cylinder 11, a timer piston 12 housed within the cylinder, a lever 14 connected to the cylinder via a pin 13, a roller holder 15 to which the lever is fixed, and the piston attached to the injection timing retard side. It is made up of a timer spring 16 etc. that exerts pressure on the back surface 1 of the piston 12 through an oil feed hole 17.
The timer piston can slide to a position where the force due to the hydraulic pressure of the fuel flowing from the feed pump flowing into the control chamber 19 formed at 8 is balanced with the force of the timer spring, and the lever is accordingly moved. The roller holder rotates through the roller holder, changing the rotational phase with the drive shaft 20, and rotating the roller 2.
1 and the cam disk (not shown),
Fuel injection timing can be adjusted.

Further, the cold start device 50 includes:
The housing 51 , the differential plunger 52 housed therein, the pressure chamber 53 formed by both, and the plunger tip 54 extend through the control chamber 19 and come into contact with the back surface 18 of the timer piston 12 . In addition to an actuating section including a plunger spring 55 that urges the control chamber 19 and the pressure chamber 53 into contact with each other, there is also an oil supply path 5 that communicates the control chamber 19 with the pressure chamber 53.
6, a control valve 57 disposed in the middle thereof, a key switch 58 for controlling the opening and closing of the valve, a temperature switch 61, a battery 59, and the like. The key switch 5
8 and a temperature switch 61 are connected in parallel between the battery 59 and the control valve 57. When the key switch is turned on, the starter motor 60 rotates and the engine is started, and the temperature switch When the cooling water temperature is below the set value
It turns on and turns off when it exceeds that point.
Further, the control valve is of a normally open type and closes the oil feed passage 56 only when energized. Therefore, communication between the control chamber 19 and the pressure chamber 53, which can be communicated via the oil feed path 56, is cut off only while any of the above switches is on.

In the starting angle device of the present invention configured as described above, when starting the engine, the starter motor 60
When the key switch 58 is turned on to rotate the control valve 57, the control valve 57 is also energized and the control room 19 of the timer 10 and the cold start device 5 are turned on.
Communication with the pressure chamber 53 of 0 is cut off. Therefore, no hydraulic pressure acts on the pressure chamber. Therefore, the differential plunger 52 is pushed out to the left in the figure by the plunger spring 55, and its tip 54 contacts the back surface 18 of the timer piston 12, pushing it against the timer spring 16 to set the fuel injection timing. Slide it in the direction of advancement (to the left in the figure).

The advance angle continues as long as the starter motor 60 is rotating, but when the key switch 58 is operated after the engine is started to stop the motor, the starting system 62 simultaneously controls the advance angle. Power to the valve 57 is also cut off. At this time, if the engine coolant temperature is low and temperature switch 61 is ON, this key switch
Even after turning off, the control valve continues to be energized from the temperature system 63, and the same advance angle as at startup is maintained until warm-up is completed and the temperature switch is turned off or the engine speed increases. .

Of course, if the temperature switch is also OFF when the key switch is OFF, the control valve is opened at this point, and the hydraulic pressure from the feed pump acting on the control chamber 19 is transferred to the pressure chamber 53 via the oil passage 56. , and the differential plunger 52 is pushed back to the right in the figure by the pressure against the plunger spring 53. As a result, its tip 54 no longer comes into contact with the timer piston 12, and the piston absorbs the force of the hydraulic pressure acting on the control chamber 19 and the timer spring 1.
It can freely slide to a position balanced with the force of 6, cancel the advance function of the cold start device 50, and perform the timer's original advance function.

Further, when the engine speed is increased to, for example, 2000 rpm while the temperature switch 61 is on, the oil pressure sent to the control chamber 19 increases, and this oil pressure is transferred to the differential plunger 5.
2, the plunger is pushed back against its spring 55. As a result, the seal 64, which was acting to cut off the communication between the control chamber 19 and the pressure chamber 53, also moves together with the plunger, and the two chambers are brought into communication. Therefore, from this point on, the sending oil pressure will also act on the pressure chamber with a large pressure-receiving area, and it will be possible to continue pushing back the plunger even when the engine speed drops to idling, and the function of the cold start device 50 will be canceled. As a result, only the advance angle function of the timer 10 is exerted.

Or, even if the engine speed is not high,
Cooling water temperature rises and temperature switch 61 turns OFF
Then, the power to the control valve 57 is cut off, the oil passage 56 is opened, the control chamber 19 and the pressure chamber 53 are communicated, and the oil pressure is introduced therein, so that the cold start device 50 is activated as described above.
function is canceled.

As described above, according to the starting angle device of the present invention, when the engine cooling water temperature is higher than the set value, the fuel injection timing is forcibly advanced only while the starter motor 62 is rotating, and the fuel injection timing is forcibly advanced only while the starter motor 62 is rotating. If is below the set value, the engine speed will be increased or
Alternatively, it is possible to continue advancing the same period until the temperature exceeds the set value, which eliminates the problems with the conventionally known cold start devices as described above, and makes effective use of its advantages. be.

In the figure, 65 is a diode which prevents the starter motor from rotating when the key switch is OFF and the temperature switch is ON.

[Brief explanation of the drawing]

The figure is a longitudinal cross-sectional view of a main part of a distribution pump showing an embodiment of the present invention. 10; timer, 12; timer piston, 16;
Timer spring, 19; Control room, 50; Cold start device, 52; Differential plunger, 53; Pressure chamber, 55; Plunger spring, 56; Oil passage, 57; Control valve, 58; Key switch, 60; Starter motor , 61; temperature switch, 62; starting system, 63;
Temperature system, 64; seal.

Claims (1)

[Scope of utility model registration request] It has a timer piston that slides to a position where the oil pressure of the fuel from the feed pump flowing into the control room and the tension of the timer spring are balanced, and a roller holder connected to the piston via a lever. Accordingly, there is provided a timer for controlling fuel injection timing, and a differential which is housed in a housing and has a tip that extends through the control chamber and can come into contact with the timer piston, and which cooperates with the housing to form a pressure chamber. A cold start device including an allencial plunger and a plunger spring that presses the plunger in the direction of the timer piston, a control valve disposed in an oil passage communicating the control chamber and the pressure chamber, a battery, and the like. The control valve is equipped with a key switch, a temperature switch, etc., which are connected in parallel with each other, and the control valve is set when the key switch is turned on to start the engine and the starter motor is rotating, and the engine temperature is set. The starting advance angle device is characterized in that the oil feed passage is closed only while the temperature is below the temperature value and the temperature switch is ON.