JP3436766B2 - Intake device for internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] Field of the Invention The present invention is provided with a resonance intake system de
It relates to diesel engines . 2. Description of the Related Art An intake system of an internal combustion engine is mainly composed of an intake manifold connected to an intake port of each cylinder, and an intake pipe connected upstream of the intake manifold. It is set so that a high intake pressure can be obtained and the volume efficiency (filling efficiency) can be improved. [0003] Further, there has been proposed an intake system configured to exhibit a known resonance effect to improve the engine output (for example, "Engine Intake System", Japanese Patent Application Laid-Open No. 1-280631). . [0004] In recent years, there has been a strong demand for improvement of exhaust gas, in particular, reduction of black smoke (smoke) emitted from a diesel engine as much as possible. [0005] However, in a high-speed engine or the like,
It has been difficult to match the combustion system so that the smoke is low over the entire range from the extremely low speed range at the start to the maximum speed at the rated point. As shown in FIG. 5, the smoke becomes better as the volumetric efficiency (filling efficiency) is higher, but the volumetric efficiency tends to decrease as the engine speed increases. For this reason, there is a problem that smoke in the high-speed rotation region is deteriorated. [0006] In view of the above circumstances, the present invention provides a diesel engine capable of preventing deterioration of smoke in a high-speed rotation region.
It was conceived to provide a down. [0007] Diesel according to the present invention
In the engine, cylinders whose intake order is not continuous
And grouping them into groups
Provide an inlet cover connected to the port, and
Connect the resonance supercharging pipes to the
The resonance supercharging pipe at the pressure reversal part for resonance
Constructs a resonance intake system, and the resonance tuning speed of this resonance intake system
To the rated speed at which the maximum output of the engine can be obtained.
Matched for low smoke in the speed range
Vertical section of the combustion chamber, recessed in the crown of the piston
Mainly defined by a circular toroidal cavity
Diaphragm that is narrowed to around 50% of the maximum diameter of the cavity
It has an opening, and the top surface is frustoconical in the center of the cavity.
A combustion chamber having a convex portion is provided.
A fuel injection nozzle for injecting fuel is provided.
The fuel injection timing and spray direction from the
The fuel spray is fixed at the piston rise speed
At the top dead center of the cavity
So that in the low-speed range,
Smoke is reduced by the system.
The smoke is reduced by the resonance supercharging action of the resonance intake system.
It is configured as follows. With the above arrangement, the resonance intake system performs resonance supercharging on the high-speed side of the engine to prevent a reduction in volume efficiency. Also above
Depending on the combustion chamber and the injection mode,
Reduce the risk of damage. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a diesel engine according to the present invention.
FIG. 2 shows an intake device of an in-line type, which is applied to an in-line six-cylinder diesel engine. In this intake device, the cylinders whose intake order is not continuous are appropriately connected to each other to form a resonance intake system 1, and the resonance tuning speed N _{r of the} resonance intake system 1 is formed. But rated speed maximum output of the engine is obtained N _p Is configured to match. The intake order (explosion order) of the six cylinders is # 1 →
# 4 → # 2 → # 5 → # 3 → # 6 → # 1 → ..., and non-consecutive cylinders are grouped as the same group
The front side (# 1, # 2)
, # 3 cylinders 2, 3, 4) and rear side (# 4, # 5
, # 6 cylinders 5, 6, 7). Inlet groups 9 and 10 connected to the intake ports 8 are provided for each of these groups, so that the intake air is equally distributed. Resonance supercharging pipes 11 and 12 are connected to the inlet covers 9 and 10 at positions near the center of the engine, and extend in a direction substantially orthogonal to the cylinder rows. These resonance supercharging pipes 1
The units 1 and 12 are combined at a resonance pressure reversing unit 13 provided on the upstream side and connected to one intake pipe 14. That is, the intake port 8, the inlet covers 9, 10, the resonance supercharging pipes 11, 12, the resonance pressure reversing section 13, and the like constitute the resonance intake system 1. In the resonance intake system 1, in each group, a pressure wave generated by the operation of each of the cylinders 2... 7 propagates between the intake port 8 and the pressure reversing section 13 to generate pressure vibration. Then, the cycle of the natural vibration of the resonance intake system 1 matches the suction cycle of each group (the natural frequency ν _r).
7 coincides with the number of inhalations for each group), the pressure waves generated in the cylinders 2... 7 of the same group resonate, and the pressure vibration is maximized. Engine speed becomes this state, a resonance tuning rotational speed N _r. [0013] Therefore resonance tuning rotational speed N _r are those related to the natural frequency [nu _r of the resonant intake system 1, the natural frequency [nu _r, the volume of the resonant intake system 1, the cross-sectional area, at length, etc. It is determined. In other words, the dimensions of such resonance supercharging pipe 11 and 12 are formed such that the rated speed N _p of the resonant tuning rotational speed N _r = engine. In this embodiment, the combustion chambers of the engine are matched so that the smoke is low in the low-speed region. As shown in FIG. 2, the combustion chamber 15
It is mainly formed by an annular cavity 17 having a circular vertical cross section depressed in the crown of the piston 16 and has a throttle opening 18 narrowed to about 50% of its maximum diameter. A projection 19 having a frustoconical shape is formed. Therefore, the intake air flows along the side wall of the cavity from the opening 18 as shown by the arrow a in the figure, and turns in the vertical direction as a moderately strong flow.
It is well mixed with the fuel spray 21 injected from zero. At this time, the fuel injection timing and the spray direction are adjusted according to the piston rising speed, which is a low speed region.
Is adjusted to be relatively shallow so that at the top dead center of the piston, it reaches the vicinity of the bending start point 22 on the side wall of the cavity 17. [0015] Thus, since by suitably form a resonant supercharging pipe 11 and 12, etc. constitute a resonance intake system 1 having equal resonance tuning rotational speed N _r a rated rotational speed N _p, the maximum output of the engine resonance effect is exhibited at the rated rotational speed N _p and the high speed range in the vicinity thereof, it is possible to perform good supercharging. That is, as shown in FIG. 3, it is possible to increase the volumetric efficiency which has conventionally been reduced on the high speed side, and it is possible to prevent the deterioration of smoke. In this embodiment, as shown in FIG. 4, the combustion chamber 15 having a function of preventing smoke deterioration on the low-speed side alone (broken line in the figure) alone is combined, so that it can be operated from a low speed to a high speed. An engine with low smoke over the entire area is achieved. In addition, there is a conventional intake device in which resonance supercharging matching is performed so as to resonate at a low rotation speed, and a resonance effect canceling valve is controlled to prevent a reduction in volumetric efficiency at a high rotation speed. The apparatus of the embodiment does not require such control, and realizes reduction of smoke in the entire rotation range with a simple mechanism. FIG. 2 shows a low-speed matching combustion chamber.
Is not limited to the configuration shown in
162925 (“Air-compression valve-controlled internal combustion engine”)
Can be employed. In this embodiment, the present invention is applied to a row type six-cylinder engine. However, the present invention is naturally applicable to other multi-cylinder engines and V-type engines. In summary, according to the present invention, the following excellent effects are exhibited. Decrease in volumetric efficiency at high engine speed
To reduce smoke and reduce engine speed
Smoke can be reduced and the entire range from low to high
Low smoke.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an intake device for a diesel engine according to the present invention. FIG. 2 is a side sectional view showing a combustion chamber used together with the intake device of FIG. 1; FIG. 3 is a diagram illustrating the relationship between volumetric efficiency and engine speed for explaining the operation and effect of the present invention. FIG. 4 is a diagram illustrating the relationship between smoke and engine speed for explaining the operation and effect of the present invention. FIG. 5 is a diagram illustrating a relationship between smoke and volume efficiency for explaining a problem of the related art. [Description of Signs] 1 Resonance intake system 2 # 1 cylinder 3 # 2 cylinder 4 # 3 cylinder 5 # 4 cylinder 6 # 5 cylinder 7 # 6 cylinder 8 intake port 9,10 inlet cover 11,12 resonance supercharging pipe 13 resonance use the pressure reversing part 15 combustion chamber 16 the piston 17 cavity 18 iris opening 19 protrusions 20 a fuel injection nozzle 22 curved starting point N _r resonance tuning rotational speed N _p rated speed

   ────────────────────────────────────────────────── ─── Continuation of front page       (56) References JP-A-4-1415 (JP, A)                 JP-A-4-94414 (JP, A)                 Shokai Sho 56-120316 (JP, U)                 Real opening 58-1425 (JP, U)                 63-132834 (JP, U)                 Shokai Sho 56-85023 (JP, U)                 Hikaru Hei 3-73642 (JP, U)

Claims (1)

(57) [Claims] [Claim 1] Cylinders whose intake order is not continuous are the same group.
Loops are grouped, and for each of these groups
Provide an inlet cover connected to the air port
Connect the resonance supercharging pipes to the
Summarize these resonance supercharging pipes in the resonance pressure reversal section
To form a resonance intake system, and adjust the resonance tuning speed of the resonance intake system to obtain the maximum output of the engine.
Matching with the rated rotation speed, and low smoke in the low-speed region.
Longitudinal section of a closed combustion chamber, recessed in the crown of the piston
Primarily defined by a circular toroidal cavity
And a diaphragm narrowed to about 50% of the maximum diameter of the cavity.
With a frusto-conical opening at the center of the cavity
A combustion chamber provided with a convex portion exhibiting
A fuel injection nozzle for injecting fuel, and a fuel injection timing and a spray method from the fuel injection nozzle.
Direction in accordance with the piston rise speed, which is the low-speed region.
Spray starts to bend the side wall of cavity at top dead center of piston
Point, and smoke is mainly generated by the combustion system of the engine in the low-speed range.
In the high-speed range, the resonance intake system
It is configured to reduce smoke by the sound supercharging effect
A diesel engine characterized by that: