JPS60187737A - Diesel engine with auxiliary injection means - Google Patents

Abstract

PURPOSE:To reduce emission of black smoke and to facilitate control of fuel injection, by advancing the ignition timing by keeping the fuel pressure of an auxiliary injection valve at a constant level, and controlling the auxiliary fuel injection valve according to the operational conditions of an engine. CONSTITUTION:A pulse signal having a frequency proportional to the engine speed and the engine load detected respectively by an engine-speed sensor D1 and a throttle lever opening sensor D2 is applied to a control unit 46, and a control signal S is applied to an electromagnetic injection valve 20 on the basis of said pulse signal. When the opening of a throttle lever becomes greater than a predetermined angle with increasing of the engine load, the injection period is so controlled that fuel is injected from the injection valve 20 at a predetermined rate (10-20%) to the total injection quantity of fuel according to the engine speed. Thus, since pre-flaming reaction is caused before main fuel ejected from a main injection valve 14 is ignited and the ignition of fuel is advanced, emission of black smoke is reduced. Further, since injection of fuel into an intake pipe is effected only at the time of high-load operation of an engine, increasing of HC contained in the exhaust gas is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an improvement in a diesel engine equipped with an IC auxiliary injection device in which an auxiliary fuel injection valve is provided in an intake pipe.

[Prior Art] In order to reduce black smoke from diesel engine exhaust, a fuel migration system has been proposed in which an auxiliary injection nozzle is installed in the intake pipe of a diesel engine to eject a portion of the fuel. There is.

However, according to the above system, it is necessary to additionally provide the fuel injection pump with a plunger for supplying high-pressure fuel to the auxiliary injection nozzle, and since the plunger for auxiliary injection has a different fuel injection distance of 1 m, it is necessary to add a plunger to the fuel injection pump. There was a problem in that it was very difficult to control the amount. On the other hand, if the plansite is provided separately and independently, the fuel injection pump,
There were problems in that the fuel injection system, including piping, etc. needed to be significantly changed, raising production costs and making it difficult to adopt a fumigation system.

Also, when the fuel pressure to the auxiliary injection valve fluctuates,
There was a problem in that the injection timing had to be changed accordingly, making injection control very difficult.

[Object of the Invention] The present invention has been made against the background of the above, and an object of the present invention is to easily control the injection amount to the auxiliary injection nozzle, and to significantly modify the fuel injection system. The object of the present invention is to provide a diesel engine with an auxiliary injection device that does not require.

[Structure of the Invention] The gist of the present invention, which has been made to achieve such an object, is to provide a fuel injection pump for pressure-feeding fuel to a main injection valve that injects fuel into a combustion chamber. In a diesel engine with an auxiliary injection device, in which an auxiliary fuel injection valve is provided in an intake pipe for supplying air into a combustion chamber, the injection pump maintains fuel pressure at a predetermined constant pressure lower than the fuel pressure setting pressure of the main injection valve. a constant fuel pressure control section that can supply fuel to the auxiliary fuel injection valve via the constant fuel pressure control section, and receiving commands from a control unit that determines the operating state of the diesel engine itself. This is because the auxiliary fuel injection valve is configured to be controllable.

[Example] Embodiments of the present invention will be described in detail below based on the drawings.

In FIG. 1, 10 is an engine body, and the engine body 10 includes a main injection valve 1 that injects fuel into a combustion chamber 12.
4 is installed, and an intake pipe 16 for feeding air into the combustion chamber 12 is installed, and an electromagnetic injection valve 20 as an auxiliary fuel injection valve is installed in a surge tank 18 provided in the intake pipe 16. There is. The surge tank 18 forms a branch point of a plurality of intake pipes that communicate with each cylinder 22 (only one cylinder is shown in FIG. 1, the others are omitted).
The electromagnetic injection valve 20 is located on the upstream side of the branch of each intake pipe.

High-pressure fuel discharged from the delivery pulp 26 of the fuel injection pump 24 can be supplied to the main injection valve 14, and the electromagnetic injection valve 20 is supplied from the upstream side of the pressure control valve 28 as a constant fuel pressure control section. Fuel at a predetermined pressure can be supplied through a pipe 30. The fuel injection pump 24 is a well-known distribution type injection pump commonly referred to as a VE pump with a pressure control valve 28 and a conduit 30 added, and a detailed explanation of the well-known parts will be omitted. The upper feed pump 32 in FIG. 1 is shown extending 90 degrees from the axis of the drive shaft 34. The fuel at the discharge pressure P1 of the feed pump 32 can be delivered to the delivery pulp 26 through the inside of the injection pump 24, and the flow path communicating with the discharge port of the feed pump 32 is set at a predetermined fuel supply pressure. A pressure control valve 36 is provided to control the pressure to a pressure of
The fuel is then returned to the fuel intake flow path 40.

The return flow path 38 is provided with a three-pressure control well 28 in which a ball valve can be seated on the seat portion by a compression coil spring, and the pressure on the upstream side of the pressure control valve 28 is maintained at a constant pressure P2. , fuel can be supplied to the electromagnetic injection valve 20 through the conduit 30 at a constant pressure. The fuel pressure P2 is lower than Pl and is a constant fixed pressure. In this example, Pl is approximately 2 to 3k(]/cn'
It is set to t. Pl varies depending on the engine speed, but is approximately 150k (1/ci (maximum)). Fig. 2 shows the relationship between fuel pressure of P+ and Pl with respect to the engine speed.

In place of the pressure control valve 28 of the embodiment described above, a constant pressure chamber 44 with a pressure control valve 42 having the same structure as described above is provided in a chamber communicating with the discharge side of the feed pump 32, as shown in FIG. Fuel may be supplied to the electromagnetic injection valve 20 from the constant pressure saw chamber 44.

The electromagnetic injection valve 20 is configured similarly to a well-known electromagnetic fuel injection valve used in an electronically controlled fuel injection system (EFI) of a gasoline engine, and when a signal from the control unit 46 is input, a signal is generated. l1ll depending on
It has been possible to control the sword time.

The diesel engine 1 is equipped with an engine rotation sensor D1 and a throttle lever opening sensor D2, and a pulse signal with a frequency proportional to the engine rotation speed and engine load is sent to the engine 1 to roll unit 46. added as input to . The control unit 46 is
Based on this input, combustion speed, injection amount, etc. are calculated, and a control signal S is outputted and input to the electromagnetic injection valve 20. When the engine load increases and the throttle lever reaches a predetermined level or more, the electromagnetic injection valve 20 sends a signal to the total injected fuel (6) at a fixed ratio (10 to 20 The injection time is controlled so that about 30% of the fuel is injected.

In the embodiment configured as described above, when the engine load increases, the electromagnetic injection valve 20 is adjusted so that the injection amount of the electromagnetic injection valve 20 becomes a predetermined ratio to the total injection amount according to the engine speed. The nozzle opening/closing time is controlled and fuel is injected at a constant pressure. The injected fuel mixes sufficiently with the intake air and is compressed in the fuel chamber, causing a so-called pre-flame reaction before the main fuel is injected from the main injection valve 14 and ignited, which has the effect of hastening ignition. Also, since mixing with air is promoted, exhaust black smoke is reduced.

Therefore, when looking at the same exhaust heat fi 11 degrees, the output improves. Additionally, noise is reduced due to faster ignition.

Furthermore, in fucomigation systems, there is a tendency for 1'C (hydrocarbons) to increase under light loads, but in this example, l-('C) is injected into the intake pipe only at high loads. The problem of C increasing does not occur.Also,
Since the fuel pressure injected into the intake pipe is constant, it has the advantage of being easy to control. Since the above-mentioned embodiment does not require any major changes to the fuel injection system, it can be easily applied to diesel engines that are currently mass-produced, and can prevent high production costs due to the adoption of a fumigation system. .

FIG. 4 shows another embodiment of the present invention, in which a so-called Air Assist 1 complete injection nozzle is used as the electromagnetic injection valve 50. A compressor (not shown) driven by the engine pressurizes the Assis 1 to about 21 (g/-) and leads it by a conduit 52 to the nozzle.

Since the spray injected by the injection valve 50 is fine, the distribution between the cylinders is particularly good in a multi-cylinder engine, and since the spray is fine, the foreflame reaction mentioned above becomes active, and it also interacts with the air. Since the mixing is also better, there is an advantage that the effect of reducing exhaust black smoke and shortening ignition is significant.

FIG. 5 shows another embodiment of the present invention, which is a case of an engine with a turbocharger 56. The intake duct 58 from the turbocharger V56 to the intake pipe 16 is formed (the electromagnetic injection valve 20 is installed on the upstream side).
There is.

In this way, it takes a long time to reach the combustion chamber, and when supercharging, the intake temperature increases, promoting vaporization of the fuel, resulting in better mixing with air.
Therefore, as described above, the foreflame reaction is promoted and the effect of fuel auxiliary injection is increased.

In each of the embodiments described above, it is possible to provide an auxiliary injection valve for each intake pipe, and it is also possible to use a morning type injection pump as the fuel injection pump.

Although several embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way, and can be implemented in a wide variety of ways without departing from the gist of the present invention. Of course.

[Effects of the Invention] As detailed above, according to the present invention, since the fuel is injected by the auxiliary fuel injection valve in the intake pipe, the injected fuel is sufficiently mixed with the intake air. The fuel is compressed in the combustion chamber, and before it is injected from the main injection valve and ignited, a so-called pre-flame reaction occurs, which hastens ignition. Furthermore, since mixing with air is promoted, combustion is carried out more efficiently and the generation of exhaust black coal is reduced. With this, 1. The output is improved in terms of exhaust black flame depth.

Furthermore, noise is reduced due to improved ignitability.

Furthermore, since the pressure of the fuel injected into the intake pipe is constant, the injection can be easily controlled. In addition, since the conventional fuel injection system is equipped with a constant fuel pressure control section that keeps the fuel pressure of the auxiliary injection valve constant, there is no need for major modification of the fuel injection system itself, resulting in improved fuel injection. Prevent the rise in production costs associated with the adoption of the system. Furthermore, since the auxiliary fuel injection valve can be controlled in response to a command from the control unit that determines the operating state of the engine, it is possible to suitably control the auxiliary fuel injection valve according to the operating state.

[Brief explanation of the drawing]

Fig. 1 is an explanatory cross-sectional view of the main part showing one embodiment of the present invention, Fig. 2 is a graph showing the pressure change characteristics of the injection pump used in the same embodiment, and Fig. 3 is used in the same embodiment. FIG. 2 is a main part explanatory diagram showing another constant fuel pressure control section that can be used in place of the pressure control valve. FIG. 4 is a partially cross-sectional explanatory view of the main part showing another embodiment of the present invention, and FIG. 5 is a partially cross-sectional explanatory view of the main part showing still another embodiment of the present invention. 12... Combustion chamber 14... Main injection valve 16... Intake pipe 2.0,5'O... Electromagnetic injection valve (auxiliary fuel injection valve) 2
4... Fuel @ Sword Pump 28... Pressure control valve (constant fuel pressure control section) 44... Constant pressure chamber (constant fuel pressure control section) Agent Patent attorney Seitatsu Kenka 1 person Figure 1 Figure 2 Figure 3 ↑ Figure 4 Figure 5 Commissioner of the Japan Patent Office Kazuo Wakasugi Representative of diesel engine with auxiliary injection 04 device Masatoshi Todorota

Claims (1)

[Claims] 1. A fuel injection pump is provided to forcefully feed fuel to the main injection valve that injects fuel into the combustion chamber, and auxiliary fuel is provided to the intake pipe to supply air into the combustion chamber. In a diesel engine equipped with an auxiliary injection device equipped with an auxiliary injection valve, the injection pump is equipped with a constant fuel pressure control unit that maintains the fuel pressure at a predetermined constant pressure that is lower than the fuel pressure setting pressure of the main IIJ1 control valve. (The auxiliary fuel @ side is capable of supplying fuel to the auxiliary fuel injection valve via the constant combustion 1-pressure control unit, and receives a command from the control unit that judges the operating state of the diesel type itself.) A diesel engine with an auxiliary injection device characterized in that the valve is configured to be controllable. 2. The auxiliary fuel injection valve is provided upstream of a branch part of an intake pipe communicating with each cylinder, and is connected to a control unit. A diesel engine with an auxiliary injection device according to claim 1, which is an electromagnetic injection valve capable of controlling injection based on a signal.3. The return circuit is provided in a return passage for returning the fuel relieved from the pressure control valve No. 1 to the fuel suction pipe of the fuel injection pump, and maintains the upstream side of the return circuit in which it is provided at a predetermined constant pressure)j. 3. A diesel engine with an auxiliary injection device according to claim 1 or 2, wherein the second pressure control valve is a second pressure control valve. 4. The auxiliary 11111J valve has a nozzle to guide the linear to the compressor driven by the diesel engine itself. Claims 1 to 3 above. Diesel engine with auxiliary injection device as described in . 5. The diesel engine itself is a diesel engine equipped with a turbocharger, and the nozzle of the auxiliary injection valve is provided on the upstream side of the intake pipe from the turbocharger to the intake pipe. The diesel engine with an auxiliary injection device according to any one of paragraph 4.