JPS63255543A - Two-cycle engine - Google Patents

Abstract

PURPOSE:To allow the fuel injection function of a two-cycle engine to operate at optimum efficiency by furnishing a control means to control the injection timing and amount of fuel injection valves arranged on a main and an aux. suction passage. CONSTITUTION:Besides a main suction passage 22 to introduce new air into a crank chamber 21, the two-cycle engine 10 is equipped with an aux. suction passage 30 to introduce new air directly into the crank chamber 21. In this engine 10, No.1 injector 34 and No.2 injector 36 are arranged on these suction passages 22 and 30, respectively. A crank chamber pressure signal from a pressure sensor 50 and signals from a crank sensor 52 and pulser coil 56 are fed into a central processing unit 54, which judges cylinder on the basis of these signals and determines optimum fuel injection timing and injection amount about the injectors 34, 36, and applicable signal is sent. Because the injectors 34, 36 can thus work with optimum injection timing and injection amount through electronical control, effective output can be drawn out of the engine 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a two-stroke engine, and more particularly to a two-stroke engine having two different paths of main intake passage and auxiliary intake passage.

[Prior Art] Generally, in a two-stroke engine, fresh air is introduced into the crank chamber, compressed by a piston, and introduced into the cylinder from a scavenging boat. Here, in order to improve intake efficiency, it has been considered to make the intake passage the main intake passage, and to provide a separate sub-intake passage for introducing fresh air directly into the cylinder.

On the other hand, conventionally, two-stroke engines equipped with a fuel injection device as a fuel supply system have been developed.

[Problems to be solved by the invention] Here, as described above, in a two-stroke engine in which a main intake passage and a sub-intake passage are provided, when each intake system is a fuel injection system, various problems arise. . In other words, if fuel is injected from only one side of the auxiliary intake passage, air and fuel will not be mixed efficiently in the auxiliary intake passage, and therefore an appropriate mixture (fresh air) may not be formed. .

In addition, if the injection timing of the fuel injection valve is inappropriate, the injected fuel may not be sucked into the cylinder during one intake stroke and remain in the intake passage, and the fuel may blow back and flow out of the intake passage. Sometimes I get blown away. This leads to deterioration of fuel consumption rate and reduction of engine output.

The present invention has been made to solve the problems of the prior art, and its purpose is to change the fuel injection method to a two-stroke engine equipped with two intake passages. The object of the present invention is to provide a two-stroke engine that exhibits an optimally efficient fuel injection function.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides, in addition to a main intake passage that introduces fresh air into the crank chamber, a sub intake passage that introduces fresh air directly into the crank chamber. In this two-stroke engine, a fuel injection valve is arranged in each intake passage, and a control means for controlling the injection timing and injection amount of each fuel injection valve is provided.

[Effect J] With this configuration, a sub-intake passage is provided in addition to the main intake passage, improving intake efficiency, and the fuel injection valves placed in each intake passage are electronically controlled to optimize injection timing and injection. It has a large capacity and can solve the problems encountered in the past.

[Example code] The present invention will be explained below based on embodiments shown in the drawings.

FIG. 1 shows an overall configuration diagram of a two-stroke engine according to the present invention. Here, reference numeral 10 is a two-stroke engine, 12 is a cylinder, 14 is a piston, 16 is a connecting rod, 18 is a crankshaft, and 20 is a crankcase, which forms a crank chamber 21. Crank chamber 21
A main intake passage 22 is connected to the main intake passage 2.
By providing a reed valve 24 in the main intake passage 22, the main intake passage 22 adopts a so-called reed valve type fresh air intake system. Fresh air introduced from the main intake passage 22 is introduced into the cylinder 12 from a scavenging port 28 via a scavenging passage 26 that opens into the crank chamber 21.

Additionally, a sub-intake passage 30 is connected within the cylinder 12, and as will be described later, fresh air is introduced from this sub-intake passage 30 in response to the reciprocating movement of the piston 14. The passage 30 employs a so-called piston valve type fresh air intake system. 32 is an exhaust passage.

The main intake passage 22 and the sub-intake passage 30 each have a first
An injector 34 and a second injector 36 are provided, and these injectors 34 and 36 are provided with a fuel tank 40.
Fuel from the area is now being introduced. That is,
The fuel in the fuel tank 40 is pumped through a filter 42 by a fuel pump 44, the pressure is regulated by a regulator 46, and then distributed to the first injector 34 and the second injector 36, and the fuel is delivered to each intake passage at a predetermined pressure. It is designed to be sprayed.

43.45 is a vibrator for pumping fuel, 48
is a pipe that allows part of the fuel to flow back into the fuel tank 40 when the fuel pressure in the regulator 46 is higher than a predetermined pressure.

The first injector 34 and the second injector 36 are each electronically controlled by a central processing unit 54, or the central processing unit 54 receives a pressure signal of the crank chamber 21 from a pressure sensor 50 attached to the crankcase 20 and a crankshaft. The signal of the crank angle sensor 52 attached to the pulser coil 5 is taken in, and the pulser coil 5
The signal No. 6 is also taken into the central processing unit 54. The central processing unit 54 determines the cylinder based on these signals, determines appropriate fuel injection timing and injection amount for each injector 34, 36, and sends the signals to the first injector 34 and the second injector 36, respectively.

The signal of the pulser coil 56 is also transmitted to the CDI unit 6
0, this CDI unit 60 controls an ignition coil 62 together with the signal from the charge coil 58, and the ignition coil 62 controls the spark plug 38.

A block diagram of a circuit for controlling the first injector 34 and the second injector 36 is shown in FIG. Here, the analog signal from the pressure sensor 50 is converted into a digital signal by the A/D converter 63 of the control unit 66 and sent to the central processing unit 54.
Signals from the crank angle sensor 52 and the pulser coil 56 are waveform-shaped by an input interface 64 and sent to the central processing unit 54. Processing signals from the central processing unit 54 are sent to an injector drive circuit 65, which controls the first injector 34 and the second injector 36. The central processing unit 54 includes an RO (not shown).
A program having a predetermined control routine is stored in this ROM.

The outline of the program will be explained based on FIG. First, in step Sl, the pressure signal in the crank chamber from the pressure sensor is taken in, and based on this, in step S2, the intake air amount is calculated, and based on this, the fuel injection amount is determined, and the optimum fuel injection time T is determined. Calculate. Next, in step S3, the injection time T4 of the first injector and the injection time T2 of the second injector are respectively calculated based on the predetermined distribution ratio k of the first and second injectors. Next, in step S4, the outputs of the crank angle sensor and the pulser coil are taken in, and based on these, the cylinder to be controlled is determined in step S5.

Next, in step s6, it is determined whether or not it is the injection start timing of the first injector, and if so, in step S7, the first injector is adjusted to the calculated injection time T.
Only □ opens. If it is determined in step S6 that it is not the injection start timing of the first injector, it is determined in step s8 whether or not it is the injection start timing of the second injector, and if so, in step S9 the second injector is The valve is only open for 12 hours. Through such a control routine, the first injector and the second injector inject fuel into each intake passage at an optimal timing and with an optimal injection amount.

FIG. 4 shows a timing chart of the intake stroke in the case of a two-stroke six-cylinder engine. Here, each number in Fig. 4 indicates the cylinder number, and the pulsar output is BTDC5~10°.
(Fixed) Progress is being made. For example, to explain the first cylinder #1 among the six cylinders, the injector on the reed valve side starts injection after identifying cylinder #4 using the pulsar output, and after the pulsar output gives a signal to identify cylinder material 2. Finish injection. On the other hand, the injector on the piston valve side of cylinder #l starts injection slightly before the injection end time of the injector on the Riet valve side, and ends the injection after the discrimination signal of cylinder #1 is received by the pulsar output. As a result, as shown in the upper part of FIG. 4, during the intake stroke for cylinder #1, injection starts from the top dead center of cylinder #4, and after the injections on the reed valve side and piston valve side overlap in the middle, Injection ends at the top dead center of cylinder #1. Note that in this upper timing chart of the intake stroke, the shaded portion indicates the injection period by the injector on the piston valve side.

Note that this timing chart is an example for a certain rotation speed; if the rotation speed and throttle opening change, the injector injection timing and injection time will also change, and the distribution ratio between the piston valve side and the Riet valve side will also change. It is possible.

[Effects] As explained above, according to the present invention, a fuel injection valve is provided for each of the main intake passage and the auxiliary intake passage,
By electronically controlling each of these fuel injection valves, optimum injection timing and injection amount can be obtained, which has the excellent effect of making it possible to obtain efficient output.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of a two-stroke engine according to the present invention, FIG. 2 is a block diagram of a control circuit in the same embodiment, FIG. 3 is a flowchart of a control routine of the control circuit, and FIG. The figure is a timing chart showing injection timing and injection time when the present invention is applied to a six-cylinder two-stroke engine. 10...Engine, 22...Main intake passage 30...
- Sub-intake passage, 34-...first injector 36...
Second injector 54...Central processing unit representative Patent attorney Yoshiyuki Inaba Procedural amendment 1. Indication of the case 1988 Patent application No. 90402 2 Name of the invention 2-stroke engine 3 Person making the amendment Relationship to the case Patent applicant Address 1400 Shinbashi-cho, Hamamatsu City, Shizuoka Prefecture Name Sanshin Kogyo Co., Ltd. 4, Agent Address 2-20-1 Yoyogi, Shibuya-ku, Tokyo 151
No. 2, No. 2 Onogi Building, 3rd floor, ``Inside the cylinder'' in the 2nd line of page 2 of the specification was changed to ``Inside the crank chamber.''

Claims (1)

[Claims] (1) In a 2-cycle engine that has a main intake passage that introduces fresh air into the crank chamber and a sub intake passage that introduces fresh air directly into the crank chamber, a fuel injection valve is arranged in each intake passage, and each A two-stroke engine equipped with a control means for controlling the injection timing and injection amount of a fuel injection valve.