JPS62118027A - Supercharger for engine - Google Patents

Abstract

PURPOSE:To improve an inertial effect in particular at the time of engine low speed, by selecting pipe length between an exciter and a suction valve so as to be conformable to a time when engine speed is low, in case of a device which installs the exciter, generating a pressure vibration of frequency commensurate to the engine speed, in a suction system. CONSTITUTION:A piston 23, which is driven by a crankshaft 24 for the exciter 20 connected to an engine crankshaft 17, is installed in a suction passage 15 of an engine 1. This piston 23 reciprocates synchronously with rotation of the engine, making a suction pipe generate a pressure wave, and performs its inertial supercharging. Length of a suction pipe 15 between a suction outlet end of the exciter 20 and a suction valve 5 is selected to that conformable to an exciting wavelength at the time of engine low speed when a vibration generating effect of the exciter 20 is little.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a supercharging vR system for an engine in which intake air is supercharged using a vibrator that generates pressure vibrations in an intake passage. be.

(Prior Art) Conventionally, a supercharging device in which a vibrator is provided in the intake system to forcibly generate pressure vibration, and the intake air is supercharged by this pressure vibration, is disclosed in, for example, Japanese Utility Model Application No. 58-14425. It is known from publications etc. The device disclosed in this publication consists of a diaphragm that forms part of the wall of a resonance chamber formed in the intake passage, and an electromagnetic vibration 2A (actuator and coil) connected to this diaphragm. The diaphragm is forced to vibrate by passing an alternating current through the coil of the W1 motor. In order to provide a supercharging effect over a wide range of engine speeds, the frequency of the alternating current applied to the coil of the vibrator is controlled according to the engine speed detection signal, thereby increasing the frequency according to the engine speed. It is designed to generate pressure vibrations.

By the way, when using a vibrator to generate pressure vibrations with a frequency that corresponds to the engine speed, in the low speed range of the engine, pressure fluctuations occur as the driving speed of the vibrator decreases. Since the pressure amplitude becomes gradual, it is difficult to provide a large pressure amplitude, and the supercharging effect tends to decrease.

(Purpose of the Invention) In view of the above circumstances, the present invention is designed to solve the problem that when supercharging intake air by forcibly generating pressure vibrations using a vibration exciter itself, the vibration exciter itself does not cause large pressure vibrations. The objective is to provide a one-engine supercharging device that can enhance the supercharging effect and improve output in the difficult low-speed drive range.

(Structure of the Invention) The present invention provides an engine intake system with a vibrator that generates pressure vibrations at a frequency corresponding to the engine rotation speed, and causes the intake system to resonate in a low-speed drive range of the vibrator. It is set so that the following occurs.

In other words, in order to achieve a supercharging effect, the above-mentioned vibrator generates pressure sensing in accordance with the engine's intake timing, and in the low-speed drive range where the amplitude of pressure is small, the technique of the intake system is used. This is designed to assist and increase low force vibration.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention. In these figures, 1 is an engine, 2 is each cylinder of the engine 1, and 3 is formed above a piston 4 in the cylinder 2. This combustion chamber 3 has an intake boat 6 opened and closed by an intake valve 5, and an exhaust boat 8 opened and closed by an exhaust valve 7. Further, reference numeral 10 denotes an intake passage that constitutes the intake system of the engine 1, and this intake passage 10
An air cleaner 11, an air flow meter 12, and a throttle valve 13 are disposed in the throttle valve 1.
A surge tank 14 is formed downstream of the pump 3, and a passage 15 formed for each cylinder communicates with the intake boat 6 from the surge tank 14. 16 is a fuel injection valve disposed in the passage 15.

The above-mentioned intake system is provided with a vibrator 20 that is driven by the output shaft 17 of the engine 1 and generates yt force vibration by operating in conjunction with the rotation of the engine. is connected. In this embodiment, the vibrator 20 includes a vibrating cylinder 22 that communicates with the surge tank 14 through a communication hole 21, and a vibrating piston 23 provided within the vibrating cylinder 22. This vibration piston 23 moves back 11 times in response to the rotation of a crank-shaped input shaft 24, and the resulting change in volume within the vibration exciter cylinder 22 causes pressure sensing. The input shaft 24 is connected to a transmission mechanism 2 consisting of a timing belt 26, pulleys 27, 28, etc.
The output shaft 17 of the engine 1 is interlocked with the output shaft 17 of the engine 1 via the shaft 5.

In the transmission mechanism 25, the vibrator piston 23
The output shaft 17 of the engine 1 and the input shaft 24 of the exciter 20 are adjusted according to the number of cylinders of the engine 1, etc. so that the period of pressure vibration caused by the reciprocating motion of the engine 1 corresponds to the intake period of the engine 1.
The rotation speed ratio is set. For example, in the case of a 4-cylinder 4-cycle engine, two cylinders perform an intake stroke during one rotation of the output shaft 17, so the output @17 and the The rotational speed ratio of the vibrator 20 to the input wa24 is set to 1:2. The timing of the reciprocating motion of the excitation piston 23 is adjusted in advance for each cylinder 2 so that the positive force 11 acts on the intake boat 6 at the end of the intake stroke. Additionally, if necessary, a clutch mechanism (not shown) may be provided between the transmission mechanism 25 and the input shaft 24 of the vibrator 20.
The clutch mechanism should be turned OFF at high speeds above a predetermined rotation speed, when the mechanical energy loss due to the operation of the vibrator 20 becomes large, at light loads that do not require supercharging, at startup, etc. The driving of the vibrator 20 may be stopped.

In addition, in the intake system equipped with the vibrator 20, the length, cross-sectional area, capacity, etc. of the 16 passages are set in relation to the resonant frequency, which will be described later, so as to avoid resonance in the low-speed drive range of the vibrator 20. Specifically, it is set to cause resonance in a low-speed driving range corresponding to a rotation speed that is one-third or less of the rotation speed at which the engine generates its maximum horsepower.

In other words, in a 4-stroke engine, if the number of cylinders is m1 and the resonance frequency is Vr (/sec), then the engine rotational speed Nr (rr) m) at which resonance occurs is Nr = 120-vr/m.
Therefore, the engine rotation speed Nma that generates the maximum horsepower is
In order to generate resonance at a rotation speed of x(rDm) of 173 or less, 120 ・V r/m< 1 /3 ・Nmax --
----- (1). In this case, the resonant frequency vr is determined by the intake passage length ρ of the flow F from the intake passage gathering part, the cross-sectional area of the intake passage, the total capacity of the downstream portion of the exciter 20, etc. For example, the resonance frequency vr is determined by the intake passage FieQ and the resonance frequency Vr. The relationship is that the longer the intake passage length Ω, the lower the resonance frequency vr. In the conventional intake system of a typical automobile engine, the above-mentioned intake passage length Q is relatively short, so the resonant frequency is high, and the above-mentioned formula (1) is not satisfied.

Therefore, for example, the intake passage length Q in E is made longer than before,
In other words, by properly forming the intake passage 10 from the air cleaner 11 to the surge tank 14, the intake system is configured to satisfy the above equation (1).

Note that the resonant frequency can also be lowered by adding volume upstream of the gathering part, so as shown in FIG. 31, or connect the tank 31 around the intake passage 10 as shown in FIG.
The intake system can also be constructed so as to satisfy the above formula (1) by forming a section 1 and communicating with the intake passage 10. Further, by increasing the volume of the surge tank 14, the resonance frequency can be lowered.

According to the supercharging device configured as described above, the engine 1
The vibration piston 23 of the vibrator 20 is driven via the transmission mechanism 25 by the operation of The vibration acts on the intake boat 6 of each cylinder 2 at a predetermined timing from the surge tank 14 via the passage 15, thereby supercharging the intake air and increasing the intake air filling efficiency. The frequency of the pressure vibrations generated by the vibrator 20 changes according to the engine speed, and pressure vibrations with a period matching the engine intake period are always applied, so that the supercharging effect is maintained over a wide range of engine speeds. can be made to last.

In this case, especially in the above embodiment, the vibrator 20 is driven by the output shaft 17 of the engine 1 and operates in conjunction with the rotation of the engine, so there is no need for electrical frequency control means. The frequency of pressure vibration can be adjusted. In addition, since the vibrator 20 is structured to generate pressure vibrations due to volume changes in the vibration cylinder 22 caused by the reciprocating motion of the vibrator piston 23, the conventional device vibrates the diaphragm with the above-mentioned alternating current. Compared to this, large pressure vibrations can be avoided and the supercharging effect can be enhanced.

By the way, even when such a vibrator 20 is used, in a low speed range, the vibration width tends to become smaller as the movement speed of the vibrator piston 23 becomes slower and the pressure fluctuation becomes gentler. . However, since the intake system is configured to generate resonance in such a low speed range, when the resonance frequency and the frequency given by the vibrator 20 almost match, as shown in FIG. Shaker 20
By combining the pressure vibration IJJ A due to the resonance and the vibration B due to the resonance, the amplitude of the composite wave C increases. Therefore, the supercharging effect is enhanced even in the low speed range.

Note that the specific structure of the vibrator 20 and the driving means for the vibrator 20 are not limited to the above embodiments, and a vibration generating member such as a diaphragm may be actuated by, for example, an electric driving means.

(Effects of the Invention) As described above, the present invention generates pressure vibrations with a frequency corresponding to the engine rotation speed using a vibrator installed in the intake system,
This supercharges the intake air, and the intake system is set so that resonance occurs in the low-speed drive range of the above-mentioned vibrator, so the pressure amplitude may be too large depending on the vibrator itself. In the low-speed drive range (L-reengine low-speed range) where it is difficult to operate, resonance can assist and increase pressure oscillations to enhance the supercharging effect and improve engine output in the low-speed range.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of a device according to an embodiment of the present invention, FIG. 2 is a schematic plan view of the same device,
3 and 4 are schematic diagrams showing different embodiments, respectively, and FIG. 5 is an explanatory diagram showing the pressure vibration increasing effect in a low speed driving range. 1... Engine, 10... Intake passage, 20... Vibrator. Patent Applicant Mazda Co., Ltd. Representative Patent Attorney Etsushi Kotani Patent Attorney Long J″l Masaaki Patent Attorney
Kuroo Itaya Figure 1 Figure 2 Figure 4 Figure 5

Claims (1)

[Claims] 1. The intake system of the engine is equipped with a vibrator that generates pressure vibrations at a frequency corresponding to the engine rotation speed, and the intake system is set to generate resonance in the low-speed drive range of the vibrator. An engine supercharging device characterized by: