JPS59110829A - Direct injection type diesel engine - Google Patents

Abstract

PURPOSE:To intensify swirl yielded in a combustion chamber and to improve combustion efficiency, by a method wherein a timing detecting means for detecting the terminal of fuel injection is mounted, and an air flow is created in a combustion chamber through actuation of means for creating an air flow according to the output thereof. CONSTITUTION:When an engine is shifted to high-rotation high-load operation, a first valve 36 is opened by means of the output of a circuit for detecting said operation, forced oil from an oil pump 30 flows in a flow-in chamber 27 of an actuator 15, and flows in a reservoir chamber 28 through a one-way valve 22. In which case, with a second valve 36 simultaneously closed, the forced oil is confined to the interior of the reservoir chamber 28, and an engaging cylinder 19 and a spherical fulcrum 14 are locked to rise position. In this case, when a drive arm 12 is pushed down by a timing cam 13 in response to timing of fuel injection terminal, swing of the arm 12 pushes down a plunger 11a of an air injection pump 11 to inject the air through an injection nozzle 16, resulting in intensification of swirl yielded in a combustion chamber 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a combustion chamber at the top of the piston, a fuel injection nozzle having a plurality of nozzle holes adjacent to the combustion chamber, and an intake air generated in the combustion chamber from the fuel injection nozzle. This invention relates to a direct injection diesel engine that injects fuel directly into a swirl and generates an air-fuel mixture through collision between the swirl and the injected fuel.

This type of direct injection diesel engine is conventionally known (see Japanese Utility Model Application No. 56-133924).

In such a direct injection engine, it is necessary to efficiently generate an air-fuel mixture in a very short period of time, and it is no exaggeration to say that the efficiency of air-fuel mixture generation governs various performances such as engine combustibility.

The efficiency of generating such a mixture is basically controlled by the strength of the swirl generated within the combustion chamber.

For this reason, in the past, the boat shape, directivity, etc. of the intake boat were set to achieve the optimal swirl strength, but in reality, it is difficult to ensure the optimal 7-whirl strength. It is difficult to

That is, the swirl is basically generated during the absorption stroke, but as the piston moves upward, the lettuce swirl generated is gradually but gradually attenuated.

For this reason, the swirl strength changes between the beginning and end of fuel blowing, and at the end of blowing, the swirl attenuates and the mixture generation efficiency decreases, slowing combustion and causing after-effects. There are problems that lead to this.

Therefore, if we set the boat shape of the intake boat so that a sufficiently strong swirl remains even when the fuel finishes blowing, the swirl becomes too strong at the beginning of the fuel blow, and if the swirl is too strong at this point. Since a large amount of mixture and air gas is generated at once, most of the combustion takes place in a short period of time, resulting in a rapid rise in combustion temperature and pressure, resulting in NOx.

A problem arises in that combustion noise is generated. This problem becomes particularly noticeable when the engine is under high load.

The present invention has been made in view of the above-mentioned conventional problem.The present invention has been made in view of the above-mentioned problems in the prior art. Its basic purpose is to improve the combustibility of the engine by generating air-fuel mixture in the combustion chamber to promote the generation of air-fuel mixture after the fuel has finished blowing.

That is, the present invention provides a surface-injection diesel engine that includes timing detection means for detecting the end of fuel injection, and air flow generation means that is activated by the timing detection means and generates air flow within the combustion chamber. After the end of fuel injection.

By using the generated air flow to create a strong swirl,
It is designed to promote the generation of air-fuel mixture.

Therefore, the air flow generation means according to the present invention can control the combustibility after the end of fuel blowing, and in particular,
If the swirl is strengthened and used to improve combustibility when the engine is under high load and requires high output, it becomes possible to achieve optimal combustion according to the engine load condition.

Hereinafter, the invention will be explained in more detail based on illustrated embodiments.

In the direct injection diesel engine 1 shown in FIG. 1, 2 is a pinuton that reciprocates in the vertical direction within the cylinder bore 4 of the cylinder body 3, 5 is a combustion chamber formed by a recess provided at the top of the pinuton 2, and 6 is a This fuel injection nozzle is attached to the cylinder head 8 so that the nozzle tip 7 (3) is located above the center of the combustion chamber 5.

As shown in FIG. 2, the direct injection diesel engine 1 takes in air through an intake port 9 that directs intake and exhaust in the circumferential direction of the combustion chamber 5 to generate a swirl S, and the pinuton 2 is at the top dead center. Immediately before reaching the combustion chamber 5, fuel is injected radially into the combustion chamber 5 from a nozzle tip 7 equipped with a plurality of nozzle holes (not shown), and a mixture is generated by a swirl S in the combustion chamber 5.
The generated air-fuel mixture undergoes self-ignition combustion through monodiabatic compression.
The basic structure is that the exhaust gas after combustion is discharged from the exhaust port IO.

The direct injection diesel engine J having the above basic structure further includes an air injection pump 1 as an air flow generating means, a drive arm J2 for driving the air injection pump 11, and a drive arm J2 for driving the drive arm 12. A timing cam 13 and a hydraulically actuated actuator 15 that supports a spherical fulcrum [4] forming a swinging skin of the drive arm [2] are provided.

(4) The air injection pump 11 is preferably a -m plunger pump with its injection hole 16 facing toward the combustion chamber 51 at the top of the piston 2, as shown in FIG.
It is inserted and fixed into a hole τ1 provided in the cylinder head 8 so as to be oriented in a direction to strengthen the swirl S inside.

The timing cam 13 is attached to a camshaft 17 that rotates once every two revolutions of the output shaft of the engine, and its cam crest is connected to the drive arm 17 at the end of injection from the fuel injection nozzle 6.
is set to a phase that allows it to swing around the hour hand in the figure with the spherical fulcrum 14 as a swing fulcrum, and after the end of fuel injection, the drive arm J2 moves the brassiere 11a against the spring force of the coil spring llb. Press down, injection hole 16
More pressurized air is injected into the combustion chamber 5. That is, the timing cam 3 constitutes a timing detecting means for driving and controlling the air injection pump J1 at an appropriate timing after the end of fuel injection.

Next, the structure and operation of the hydraulic actuator 5 supporting the spherical fulcrum 4 will be explained with reference to FIG. 3G.

Hydraulically actuated actuator 5 locks and holds the spherical fulcrum 14 in its raised position when the engine is operating at high speed and under high load, and lowers and hangs the spherical fulcrum 14 during other operations. Release the lock and prevent the drive arm 12 from operating the air injection pump]1.
This is provided to disable the spherical fulcrum of the drive arm 12.

That is, the hydraulic actuator] 5 has a bottomed cylindrical fitting tube J9 that is slidably fitted downward into a bottomed cylindrical casing 18 that is fixed to the cylinder head 8, The lower half of 19 has an inner cylinder 21 with a valve seat 20 on the upper part.
It has a basic structure in which a one-way valve 22 is biased and supported by a coil spring 23 and attached to the valve seat 20 of the inner cylinder 21, and a spherical fulcrum is provided above the fitting cylinder 19 as shown in the figure. 14 is supported.

The one-way valve 22 has a ball 25 inside a cover member 24 whose lower edge is biased and supported downward by a coil spring 23, and a ball 25 biased downward by a coil spring 26. It is partitioned into an oil inflow chamber 27 containing the inside of the inner cylinder 21 communicating with the kneading cylinder through a small hole, and an oil storage chamber 28 at the upper part of the fitting cylinder 19.

The oil inflow chamber 27 is communicated with an oil supply passage 3J connected to an oil pump 30 that pressurizes and supplies oil in the oil pan 29. A first pulp 32 is interposed therebetween. The oil storage chamber 28 is connected to an oil discharge passage 35 through a ring groove 34 provided on the outer periphery of the fitting cylinder 9 so as to communicate with the oil storage chamber 28 through a communication hole 33.
A normally open second valve 36 is interposed in the middle of the 2-year-old oil discharge passage 35 that communicates with the 2-year-old oil discharge passage 35.

Above 1st. The second valves 32, 36 are, for example, electromagnetic valves, respectively. Opening/closing driving is performed by second driver circuits 37 and 38. These first and second driver circuits 3
7.38 receives the output of the detection circuit 39 that detects when the engine is running at high engine speed (7) and is operating under high load. Activate the second valve 32,36.

The detection circuit 39 has a first threshold value e1 preset in response to the output of the accelerator opening sensor 40 and the high load of the engine.
The first comparator 4J outputs 'High' when the output exceeds the first threshold value e1, and the first comparator 4J outputs 'High' when the output exceeds the first threshold value e1. The second threshold value e2 is compared, and the output is the second threshold value e2.
a second comparator 43 that outputs "High" when the threshold value e2 is exceeded; When the second comparators 41 and 43 simultaneously output "High", the first and second comparators 41 and 43 simultaneously output "High". It consists of an AND circuit 44 that outputs 'High' to the second driver circuits 37 and 38.

Now, the engine is the first one above. Second threshold el.

When the operating state is other than the high-speed, high-load operation set by e2, that is, the normal operating state, the first pulp 32 is closed, the second valve 36 is open, and the hydraulic actuator 15 ( 8) No oil is supplied to the oil inlet chamber 27, and the oil reservoir chamber 28 is open and communicated with the oil pan 29 side.

Therefore, the fitting cylinder 19 is not locked by oil,
It is merely supported by the spring force of the coil spring 26, and as the timing cam 13 rotates, the drive arm]2
When is pushed downward, this downward force causes the spherical fulcrum 14 to
As a result, the drive arm [2] is unable to operate the air injection pump J], and the air flow that strengthens the air flow inside the combustion chamber 5 is substantially prevented. Not generated. In addition, in Figure 3, 4
Reference numeral 5 designates a check valve that prevents the oil that has once flowed out of the oil storage chamber 28 from flowing back into the oil storage chamber 28.

However, the engine is the first. Second threshold value et.

Shifts to high-speed, high-load operation higher than that set by e22.
, the AND circuit 44 of the detection circuit 39
igh” is output, the first driver circuit 37 operates to open the first pulp 32, and the second driver circuit 38 operates to close the second valve 36.

Therefore, the oil pressurized by the oil pump 30 flows into the oil inflow chamber 27 through the oil supply passage 31, and as the pressure in the oil inflow chamber 27 increases, the one-way valve 22 is opened and the oil reservoir chamber 28 is opened. Oil flows inside. The oil that has flowed into the oil storage chamber 28 is confined within the oil storage chamber 28 by the one-way valve 22 and the closed second valve 36, and as a result, the i-junction 1
9 and the spherical fulcrum 14 are locked in their raised positions.

Therefore, as shown by diagonal lines in FIG. 4, when one fuel injection is performed by the fuel injection nozzle 6, the timing cam 13 moves the drive arm at the timing of the end of fuel injection corresponding to the top dead center TDC. ] 2 is pressed down, and the drive arm J2 is a locked spherical fulcrum] With 4 as a swinging fulcrum, it swings around the hour hand in the figure and pushes the plunger lla of the air injection pump 11. The pinuton IIC is lowered, and pressurized air is injected toward the combustion chamber 5 from the injection hole 6 (see the dotted line in Figure 4). As mentioned above, this injected air generates a flow within the combustion chamber 5 that strengthens the swirl S in the combustion chamber 5, and by strengthening the swirl S that has been attenuating due to this special feature, the air-fuel mixture is generated. promote.

By strengthening the swirl S, the combustion of the fuel that has already started can be completed early without any additional combustion.

In the embodiments described above, the air injection pump 11 is operated only when the engine shifts to high-speed, high-load operation, but the present invention is not limited to this. That is, the operating state in which the air injection pump 1 is operated should be determined in relation to the setting of the intake port 9, which actually controls the intensity of the swirl S.

Further, it goes without saying that the timing detection means and the air flow generation means are not limited to the above embodiments.

As is clear from the above explanation, according to the present invention, it is possible to strengthen the swirl after the end of fuel injection [11], so if the timing is set appropriately, initial combustion can be performed relatively slowly. In addition, NOx and combustion noise can be suppressed, and after ignition, swirl can be strengthened to achieve efficient combustion with less after-effects.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view of the main parts of a direct injection diesel engine showing an embodiment of the invention, Figure 2 is a plan view of the pinneton shown in Figure 1, and Figure 3 is the hydraulic pressure shown in Figure 1. FIG. 4 is a graph showing the timing of fuel injection and the timing of the operation of the air flow generating means based on the crank angle. 2... PinuFun, 5... Combustion chamber, 6...
Fuel injection nozzle, 11... Air injection pump, ]2...
・Drive arm, 13...timing cam. Patent applicant: Toyo Kogyo Co., Ltd. Agent
Person Masu Rishi Aohaku 2 people (12)

Claims (1)

[Claims] (1) In a direct injection diesel engine that has a combustion chamber at the top of the piston and a fuel injection nozzle having a plurality of injection holes attached to the combustion chamber, a timing detection means for detecting the end of fuel injection is provided, and , a direct injection type % type, characterized in that it is actuated by a timing detection means and is provided with an air flow generation means for generating an air flow within the combustion chamber.