JPH03185263A - Fuel supply device equipped with unit injector for use in multiplecylinder diesel engine - Google Patents

Abstract

PURPOSE:To make it easier to stop supplying fuel to some cylinders by connecting unit injectors to a common fuel pump through their respective fuel passages, and providing one part of the fuel passages with directional control valves for switching to the upstream side of the fuel pump the fuel forcibly fed from the fuel pump. CONSTITUTION:In a 6-cylinder diesel engine 10 wherein a unit injector 14 is provided at the top of each cylinder 12, a fuel pump 16 is provided which is driven by rotation of the crank shaft of the engine 10 through lines 18, 20 of gears Fuel 24 pumped from a fuel tank 22 by actuation of the fuel pump 16 is forcibly transmitted to each injector 14 through fuel passages 28. In this case, a common directional control valve device 30 is provided in the fuel passages 28 leading fuel from the tank 22 to the separate injectors 14 of first, second and third cylinders which are not next to each other in the order of fuel injection. At the time of light load during the warm-up of the engine, the directional control valve device 30 is switched so that fuel injection is stopped from the first to third cylinders.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel supply system for a multi-cylinder diesel engine that injects fuel into each cylinder by a unit injector, and more specifically relates to a partial shutdown of such a fuel supply system. (Hereinafter, rp.

S, D, J).

[Conventional technology]

In order to reduce the amount of NOx (nitrogen oxides) in the exhaust gas of a diesel engine, it is effective to increase the injection pressure of fuel injected into the cylinder, and fuel O with a unit injector is suitable for this purpose. (Feeding devices are becoming more effective.

On the other hand, in order to suppress white smoke and odor in the exhaust gas during light load during warm-up of the diesel engine, fuel supply to some cylinders is stopped.

S, D, are being carried out.

In a conventional fuel supply system with a unit injector, P
, S, and D, none of them had the functions.

On the other hand, in a row-type injection pump, P, S, and D are used.

In order to equip this function, a groove for increasing/decreasing the amount of fuel pumped is formed around the plunger in the injection pump that pumps fuel to the unit injector, and an injection fish effect part is added to this groove to increase the temperature. During light loads in the aircraft, the rack is displaced to allow fuel to return via the injection contact part of the plunger.

[Problem to be solved by the invention]

In the fuel co-supply system with a unit injector, the plunger is rotated by a rack to increase or decrease the fuel injection rate, so there is no structural part that increases or decreases the fuel injection rate. ).

When adding functions to single-row injection pumps,
', s, D, it is difficult to apply Yokodori as is.

The object of the invention is to provide a fuel supply system with a unit injector for diesel engine cylinders (l), S, L) with added functions.

[F-stage to solve the problem] The fuel supply device with a unit injector for a multi-cylinder diesel engine, which is the premise of this invention, has a unit injector installed in each cylinder to inject fuel into the cylinder, and a unit injector installed in each unit injector. The unit is equipped with a fuel passage that guides pressurized fuel from a common fuel pump to each unit injector. In such a device, in the fuel supply device with a unit injector for a multi-cylinder diesel engine of the present invention, a switching valve is provided in some of the fuel passages, and at the time of partial shutdown, by switching the switching valve, the fuel O( Directs the pressurized fuel from the supply pump to a location other than the unit injector.

[Effect]

At the time of fuel simulation in the passageway (non-1', S, D, time), the switching valve allows the fuel pumped from the fuel supply pump to flow to the unit injector. Due to this.

All unit injectors receive pressurized fuel from the fuel supply pump and inject the fuel, and all cylinders become operational and generate output.

On the other hand, when performing P, S, I), the switching valve is
Switched to direct pumped fuel from the fuel supply pump to a location other than the unit injector.

As a result, some of the unit injectors are not supplied with pressurized fuel from the fuel supply pump and stop injecting fuel into the cylinders. In this way, only some cylinders are operated, and the fuel is (1 (the cylinders supplied are non-I to maintain the same output).
, S, and D, and more fuel is injected than during , S, and D, and the exhaust gas temperature rises. This reduces white smoke during cold start.

[Length example]

In the following, the present invention will be described with reference to embodiments shown in the drawings.

11m is a configuration diagram of a fuel supply system for a six-cylinder diesel engine 10 equipped with a unit injector 14. This six-cylinder low-cylinder diesel engine 10 is a four-stroke engine mounted on a large-scale automobile such as a truck, and has six cylinders 12 arranged in a row in the axial direction of a crankshaft. A unit injector 14 is attached to the top of each cylinder 12 and injects fuel into the cylinder 12. The fuel supply pump 16 has a gear 20 that meshes with a gear 18 attached to the crankshaft of the six-cylinder diesel engine 10.
It receives 111 rolling force from and is driven. When the fuel supply pump 16 is driven, the fuel 24 in the fuel tank 22 is sucked into the fuel supply pump 16 through the suction passage 26, and from the fuel supply pump 16 further through the individual fuel passages 28 to each unit injector 14. be pumped.

If we number the cylinders 1, 2, 3, ..., 6 in order from the front to the cylinders 12 of a 6-cylinder diesel engine lO, then
The order of fuel injection and shaving is cylinder number 1.4.2.6.3.5, and in the cylinder 12 numbered 1.2.3, the fuel injection interval is 120' in crank angle. Switching valve device 30
is provided in the fuel passage 28 that leads fuel to the cylinders 12 numbered 1, 2, and 3, and returns the fuel 24 to the fuel tank 22 via the return passage 32 at a predetermined switching time. The return passage 32 is 3 on the switching valve system ry130 side.
Each fuel passage 28 is branched into two in the switching valve device 30.
connected to the vicinity of The computer 34 detects the battery based on input signals from a water temperature sensor 36 that measures the temperature of the cooling water of the six-cylinder diesel engine 10, and a feeding sensor 37 that detects the addition of the six-cylinder diesel engine 10 from the throttle opening and the like. Switching valve system V1 by 38
Controls the energization of 30.

FIG. 2 is a structural diagram of the switching valve device 30. In Figure 2, 5
Although only the connection of the cylinder 12 with the number cylinder 'J□1 (No. 1 cylinder) to the unit injector 14 is shown, the connection of the cylinder 12 with the number 2.
The connection to 4 is the same. The cylinder 40 extends horizontally, and has an upstream portion (fuel supply pump 16 side), a downstream portion (unit injector 14 side), and a downstream portion (unit injector 14 side) of the fuel passage 28 on the outer peripheral side.
and a branch portion of the return passage 32 are connected to each other. Cylindrical body 4
0, the connection cylindrical part of the suction passage 26 to the part on the fuel supply pump 16 side and the connection cylindrical part to the part 6 of the suction passage 26 on the unit injector 14 side are calculated with respect to the axial direction of the joint body 40, and the return passage The connection point to 32 is the suction passage 26
It is shifted in the axial direction of the cylindrical body 40 with respect to the connection point to the portion on the fuel supply pump 16 side and the connection point to the portion 6 on the unit injector 14 side of the suction passage 26. The rod-shaped valve body 42 is fitted into the cylindrical body 40 so as to be slidable in the axial direction, and has an annular groove 44 formed in its circumference. Annular: i't 44
The width changes in the circumferential direction of the rod-shaped foot body 42 and connects the fuel passage 28 on the fuel supply pump 16 side to the fuel passage 28 on the unit injector 14 side or the return passage 3z in relation to the axial position of the rod-shaped valve body 42. It is designed to connect selectively. The rod-shaped valve body 42 is made of a magnetic material at least at its end, and the solenoid 46 magnetically attracts the end of the rod-shaped valve body 42 depending on whether it is energized or de-energized, thereby displacing the rod-shaped valve body 42.

The operation of the embodiment will be explained.

The computer 34 has a water temperature sensor 36 and i'14! i
Based on the input signal from the sensor 37, it is determined whether the 6-cylinder diesel engine 10 is in the light i'i mode during warming up or other times, and the energization of the solenoid 46 of the switching device 30 is controlled according to the conditions. do. As a result, the rod-shaped valve body 4
2 is switched, and the fuel supply from the fuel supply pump 16 to the unit injector 14 of the cylinder 12 numbered 1.2°3 is controlled.

After warming up the 6-cylinder diesel engine 10 or under high load, the switching valve device! At 30, the rod-shaped valve body 42 is.

The fuel passage 28 on the fuel supply pump 16 side is connected to the fuel passage 28 on the unit injector 14 side in the axial direction, so that the unit injector 14 of the front three cylinders 12 of the six-cylinder diesel engine 10 is connected to the rear side fuel passage 28. The unit injectors 14 and J( of the three cylinders 12 receive the fuel 24 from the fuel supply pump 16 through the fuel passage 28, all the unit injectors 14 inject the fuel 24, and all the cylinders 12 are in the operating state. and generates the output.

On the other hand, when the 6-cylinder diesel engine 10 is warmed up and in the light 4.1 mode, the rod-shaped valve body 42 in the switching valve device 30 connects the fuel passage 28 on the fuel supply pump 16 side to the return passage 32. axial position, whereby for the front three cylinders 12 of the six-cylinder diesel engine IO, the fuel 24 from the fuel supply pump 16 is returned to the fuel tank 22 via the return passage 32 and the unit of these cylinders 12 is Injector 14 is not delivered fuel 24 and stops injecting fuel into cylinder 12. In this way, the operation of the front three cylinders 12 is stopped (p, S,
D, ), only the rear three cylinders 12 are operated, and the cylinders 12 numbered 4 to 6 to which fuel is supplied are non-P to maintain the same output.

More fuel is injected than during S and D, and the exhaust gas temperature increases.
As a result, white smoke during cold start is reduced.

In the illustrated embodiment, six cylinders are used as a multi-cylinder diesel engine.
I will explain about cylinder diesel engine lO,
It goes without saying that the present invention is applicable to multi-cylinder diesel engines having a number of cylinders other than six. In addition, P, S, and D in the illustrated embodiment are performed for the three front cylinders, but the number and number of cylinders for which fuel injection is stopped at P, S, and D are the same as in the embodiment. Without limitation, other numbers and combinations are also possible.

Further, in the illustrated embodiment, the fuel 24 from P, S, D, and sometimes the switching valve device 30 is returned to the fuel tank 22, but it is also possible to return it to the inlet of the fuel supply pump 16. It is.

〔Effect of the invention〕

In this invention, each unit injector is connected to a common fuel supply pump through its respective fuel passage, and some of the fuel passages are provided with a switching valve that switches the pressure-fed fuel from the fuel supply pump to the upstream side of the fuel supply pump. provided. Therefore, by switching the switching valve and stopping the supply of fuel to some unit injectors, P.

S, D, can be implemented.

[Brief explanation of drawings]

The present invention relates to an embodiment of the present invention; FIG. 1 is a configuration diagram of a fuel supply system for a six-cylinder diesel engine equipped with a unit injector, and FIG. - A structural diagram of the packaging. 10... 6-cylinder diesel engine (multi-cylinder diesel engine), 12... cylinder, 14... unit injector, 16... fuel imitation pump, 24...
・Fuel, 28... Fuel passage, 30... Encouragement valve device (
32...Return passage, 34...Computer. Diagram

Claims (1)

[Claims] (1) A multi-cylinder diesel engine equipped with a unit injector provided in each cylinder to inject fuel into the cylinder, and a fuel passage provided in each unit injector to guide pressure-fed fuel from a common fuel supply pump to each unit injector. In the fuel supply device with a unit injector for use in the fuel supply system, a switching valve is provided in some of the fuel passages, and at the time of partial shutdown, the switching valve is switched to transfer the pressurized fuel from the fuel supply pump to a location other than the unit injector. A fuel supply device with a unit injector for a multi-cylinder diesel engine.