JPH042783B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an injection amount correction device attached to a fuel injection pump in which the maximum injection amount is regulated by a bellows that expands and contracts with changes in atmospheric pressure.

[Conventional technology]

When a vehicle travels in a place with low atmospheric pressure, such as at a high altitude, the amount of air (amount of oxygen per same volume) supplied to the engine decreases, so the amount of fuel that is set under the standard atmospheric pressure (1 atm) on flat ground decreases. Regarding the injection amount, the injection amount becomes excessive relative to the air amount, causing problems such as an increase in the amount of black smoke and an increase in exhaust temperature.

Therefore, some vehicles have a high altitude correction device (aneroid compensator) attached to the fuel injection pump in order to correct the injection amount relative to the air amount at low pressure. This high altitude correction device generally uses a bellows that expands and contracts with changes in atmospheric pressure to restrict the maximum injection position of the control rack of the fuel injection pump, thereby reducing the maximum injection amount at high altitudes.

However, when the above correction device is used, the maximum injection amount decreases equally over the entire engine speed range at high altitudes, so as shown in FIG. 2, the torque relative to the engine speed also decreases as the altitude increases. As a result, in a vehicle equipped with a high altitude correction device in the fuel injection pump of the engine, starting performance at high altitudes becomes poor, and the starting torque at the time of starting is insufficient, resulting in extremely poor starting performance on flat ground.

For this reason, a device for improving engine startability at high altitudes for vehicles equipped with engines equipped with fuel injection pumps equipped with high altitude correction devices (Utility Model No. 57-
No. 49528) has been proposed, but no device has hitherto existed to improve the starting performance at high altitudes in vehicles equipped with engines equipped with fuel injection pumps with high altitude correction devices.

[Purpose of the invention]

An object of the present invention is to enable a high altitude correction device to increase the maximum injection amount of a fuel injection pump regardless of atmospheric pressure, thereby improving the starting performance of an engine at high altitudes (under low pressure) and the starting performance of a vehicle at high altitudes. An object of the present invention is to provide an excellent injection amount correction device for a fuel injection pump that can perform the following steps.

[Structure of the invention]

The injection amount correction device for a fuel injection pump according to the present invention that achieves the above object comprises: a solenoid valve capable of communicating an atmospheric communication passage of a case housing a bellows for regulating the maximum injection amount of the fuel injection pump with an air tank; Consisting of a displacement detector, a gear position detector of a transmission, an engine rotation speed detector, and a control device that controls the solenoid valve when the detector detects a starting state of the vehicle under low pressure. It is characterized by what it did.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the configuration of an injection amount correction device 10 for a fuel injection pump according to the present invention.

The high altitude correction device 2 attached to the governor 1 of the fuel injection pump includes a bellows 3 in which a constant pressure gas (air or gas body) sealed inside expands and contracts according to changes in atmospheric pressure, and a bellows 3. It is composed of a spring 5 that can be expanded and contracted via an adapter 4, and a case 6 that houses them. A push rod 7 is attached to the adapter 4, and this push rod 7 regulates the maximum injection amount position of a control rack 8 within the governor 1 that controls the injection amount of the fuel injection pump.

That is, at high altitudes where the atmospheric pressure decreases, the expansion of the bellows 3 increases the amount of immersion of the push rod 7 into the governor 1, and the maximum injection amount position of the control rack 8 at high altitudes is different from the control rack 8 at high altitudes. It is designed to be smaller than the maximum injection amount position of rack 8.
Reference numeral 9 is an adjustment screw for adjusting the degree of expansion of the bellows 3.

In the present invention, the atmospheric communication hole 11 provided in the case 6 of the high altitude correction device 2 configured as described above is connected to the high pressure air tank 13 using the conduit 12,
A three-way solenoid valve 14 is installed in the middle of this conduit 12, and the remaining connection ports are opened to the atmosphere. The three-way solenoid valve 14 is connected to the atmosphere communication hole 11 in the energized state.
is connected to the air tank 13, and the atmosphere communication hole 11 is configured to be opened to the atmosphere in an emergency state.

The high altitude correction device 2 also includes a bellows displacement switch 15 for detecting the amount of movement of the bellows 3.
is installed, and the atmospheric pressure applied to the bellows 3 is detected by the output voltage value from the displacement switch 15. The displacement switch 15 in this embodiment is a movable element 1 that moves together with the bellows 3.
5A, and a stator 15 that slides this mover 15A.
B, and the amount of movement of the bellows 3, that is, the atmospheric pressure, is detected by the change in resistance value between the two. Both the mover 15A and the stator 15B are connected to the control device 20.

A gear position detector 16 of the transmission and an engine rotation speed detector 17 are connected to this control device 20 in order to detect the starting state of the vehicle. To determine that a vehicle is in a starting state when the vehicle is in a starting state and the engine speed is below a predetermined speed.

Further, the aforementioned three-way solenoid valve 14 is connected to the starter position ST of the key switch 18 of the vehicle, so that it is connected to the battery 19 when the key switch 18 is turned to the starter position ST and the engine is cranked. Also, this three-way solenoid valve 1
4 is connected to the battery 19 via the relay 21, and the coil 21 of the relay 21
A is connected to the control device 20. and,
The control device 20 is configured to energize the relay coil 21A when the starting state of the vehicle is detected.

In the fuel injection pump injection amount correction device 10 configured as described above, at high altitudes where atmospheric pressure is low,
Key switch 18 when trying to start the engine
When set to the starter position ST, the three-way solenoid valve 14 is connected to the battery 19 via the key switch 18. Then, the three-way solenoid valve 14 communicates the atmosphere communication hole 11 of the high altitude correction device 2 with the air tank 13, so that the air pressure inside the case 6 increases and the bellows 3 contracts. This allows pushrods 7
The amount of injection into the governor 1 becomes smaller, and the maximum injection amount position of the control rack 8 is no longer regulated. Therefore, since the injection amount increases, the engine starts easily.

When the key switch 18 is returned to the ON position after startup, the three-way solenoid valve 14 is disconnected from the battery 19 and becomes de-energized, so that the high altitude correction device 2
The atmosphere communication hole 11 is communicated with the atmosphere through a three-way solenoid valve 14, and the high altitude correction device 2 regulates the maximum injection amount position of the control rack 8 according to the atmospheric pressure.

Further, when the driver subsequently tries to start the vehicle at a high altitude and sets the gear to the starting gear position (1st or 2nd gear) and depresses the accelerator, the bellows displacement occurs until the engine speed reaches a predetermined speed. Based on the signals from the switch 15, gear position detector 16, and engine speed detector 17, the control device 20 determines that the vehicle is in the starting state, and energizes the relay coil 21A. As a result, the relay 21 is turned on, and the three-way solenoid valve 14 is connected to the battery 19 via the relay 21.

Then, similarly to the above, the atmosphere communication hole 11 of the high altitude correction device 2 communicates with the air tank 13, the pressure inside the case 6 increases, and the bellows 3 contracts. As a result, similarly to the above, the maximum injection amount position of the control rack 8 is no longer restricted, the fuel injection amount increases, and the low-speed torque at the time of starting at a high altitude increases, thereby improving the starting performance of the vehicle.

Note that when the gear is shifted to 3rd speed or higher after the vehicle starts, or the engine speed increases beyond the predetermined speed, the maximum injection amount is reduced again by the action of the high altitude correction device 2.

As described above, according to the fuel injection pump injection amount correction device of the present invention, engine startability and vehicle starting performance at high altitudes are greatly improved.

〔Effect of the invention〕

As described above, the fuel injection pump injection amount correction device of the present invention includes a solenoid valve that can connect an air tank to an atmospheric communication passage of a case that houses a bellows for regulating the maximum injection amount of the fuel injection pump, and It consists of a displacement detector, a gear position detector of the transmission, an engine rotation speed detector, and a control device connected to these, and this control device uses the detector to detect the starting state of the vehicle under low pressure. By configuring the atmosphere communication path to communicate with the air tank via the solenoid valve when
This has the effect of increasing the torque in a region where the engine speed is low at high altitudes, and improving the starting performance of the vehicle at high altitudes.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the injection amount correction device for a fuel injection pump of the present invention, and FIG. 2 is an engine speed-torque characteristic according to altitude of an engine equipped with an injection pump with a high altitude correction device. FIG. 1... Governor, 2... High altitude correction device, 3... Bellows, 4... Adapter, 6... Case, 7...
Push rod, 8... Control rack, 1
0...Injection amount correction device, 11...Atmospheric communication hole, 1
3...Air tank, 14...Three-way solenoid valve, 15...
... bellows displacement switch, 16 ... gear position detector, 17 ... rotation speed detector, 20 ... control device,
21...Relay.

Claims (1)

[Claims] 1. A solenoid valve that can connect the air communication path of the case housing the bellows for regulating the maximum injection amount of the fuel injection pump to the air tank, a displacement detector of the bellows, a gear position detector of the transmission, and an engine rotation 1. An injection amount correction device for a fuel injection pump, which comprises a number detector, and a control device that controls the electromagnetic valve when the detector detects a starting state of a vehicle under low pressure.