JPS6270660A - Ignition timing control method for engine - Google Patents

Abstract

PURPOSE:To improve the output of an engine in an engine speed range higher than one for the maximum torque by controlling the ignition timing to be delayed in angle from a specified value for increasing the exhaust gas temperature when the exhaust gas temperature in an exhaust pipe is dropped. CONSTITUTION:While an engine runs, an exhaust gas temperature signal from a temperature sensor 10, and an engine speed signal from an engine speed detector 13 are inputted into an ignition timing control device 12 through amplifiers 11 and 14. In this control device 12, the optimum exhaust gas temperature for the engine speed is read out from a memory means so as to allow the outputted optimum exhaust gas temperature to be compared with the inputted actual exhaust gas temperature. And an ignition device 15 is controlled in such a way that the ignition timing is set so as to allow the exhaust gas temperature to come close to the optimum exhaust gas temperature. That is, when the actual exhaust gas temperature is below the optimum exhaust gas temperature, the ignition timing is controlled to be delayed in angle from a specified value for increasing the exhaust gas temperature so as to increase the output of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ignition timing control method for an engine, and particularly to ignition timing control for improving output in a high speed range of 1-lux rotation speed or more. It is.

(Prior Art) In order to improve the output of an engine, it is known that the dynamic effect of the exhaust pipe, so-called inertia effect, and pulsation effect are used to increase the pressure in the combustion chamber before and after ignition.

By the way, in the high rotation range above the maximum output engine rotation speed that outputs the maximum torque, the exhaust pipe is cooled by high speed running, and the exhaust temperature decreases, so the pressure wave from the end of the exhaust pipe etc. The timing to return to is slightly delayed from the best timing that occurs at maximum torque,
Output tends to decrease.

By the way, with respect to gas exchange within the cylinder, dynamic effects, that is, inertial effects and pulsation effects in the exhaust system greatly contribute. The major factor behind the J3G-J v1 effect on this exhaust system is that the temperature of the exhaust gas in the exhaust system is high, and as a result, the speed of sound is high, and when exhaust is blown out, the pressure inside the combustion chamber is is larger than the pressure in the exhaust pipe, easily reaches the critical pressure, and the excited @v energy increases, and the maximum value of the blown pressure becomes less severe as the engine speed increases, and the exhaust gas flows out. The time is shortened.

In order to obtain such a dynamic effect, in the case of a 4-stroke engine, the IJ + air system must be closed near the top dead center of the piston, where the exhaust valve and intake valve overlap between the end of the exhaust stroke and the beginning of the intake stroke. It is only necessary that the reflected wave of the negative pressure from the exhaust valve reaches the exhaust valve, and at this time, sufficient gas exchange with fresh air in the cylinder is performed due to the dynamic effect.

On the other hand, in a 2-cycle engine, if the cylinder has an exhaust hole or a negative air hole, the negative pressure reflected wave is υ1 during the period when the air hole is open.
Upon reaching the air pores, this negative pressure wave travels through the combustion chamber and IJI air passage to the crankcase and intake holes. This negative pressure that has reached the inside of the crankcase causes more fresh air to be sucked into the crankcase, so more fresh air will be sent into the combustion chamber during the next recycle. After negative pressure, the reflected wave of positive pressure reaches the exhaust hole or cotton pore, preventing fresh air from flowing out.
Ru.

The exhaust system specifications that satisfy the tuning conditions for obtaining preferable exhaust pulsation and the like as described above are generally set at the maximum torque rotation speed. On the other hand, in an engine that uses a wide range of rotational speeds, it is difficult to obtain a tuning line f[ that utilizes dynamic effects at all rotational speeds. The reason is that
Exhaust valves and intake valves are opened and closed in response to the rotation of the engine, that is, the rotation of the crankshaft. This is because the opening point cannot be changed so that dynamic effects can be utilized depending on the rotation speed. be.

Here, if the engine speed is N, the number of exhaust pulsations is n1, the exhaust pipe length is subtracted, and the speed of sound is a, then the time required per number of pulsations is t, t=1/ (n-N/60) - (1 ). Moreover, this time t is the time for reciprocating the length L of the exhaust pipe at the speed of sound, and is t = 21/a (2). Therefore, from the above formulas (1) and (2), the pulsation number n is
n= (60/N>・<a/2L>−・・(3). Since the above sound speed a is proportional to the square root of the absolute temperature T of the gas, n■(60/N)−(JT/2 [)...(4)
This relationship exists. Now, under the exhaust pulsation tuning condition, the absolute temperature of the exhaust is Tm, the engine speed is Nm,
If the length of the exhaust pipe is 1-m, the line f[, which is the same as the synchronized pulsation number, is (ETl, 1. l - (J]i
High i-L+n) ・(51 or T = (N
-L/Nm ・Lm) ・1m-= (G).

In this way, to make the exhaust pulsation rate the same as the tuning condition,
The quality of the exhaust system, that is, the length of the exhaust pipe, can be made variable and tuned to a higher or lower rotational speed than the tuning setting rotational speed. As such, JP-A-55-11
There is a variable length exhaust pipe for a two-stroke engine as shown in Japanese Patent No. 2823, but since the length of the exhaust system is made variable, the configuration of the exhaust system is complicated.

In addition, d3 is applied to the rotation speed region lower than the tuning setting rotation speed.
For example, in JP-A No. 5, the exhaust gas temperature is lowered, the sound speed of the exhaust is lowered, and the torque in the middle speed range is improved.
There is an antagonism silencer for a two-stroke engine as shown in Japanese Patent No. 8-74826. However, this device has a medium rotation speed ff1hi! The aim is only to improve the torque in the high speed range, but not in the high speed range. By the way, theoretically, in the rotation range above the maximum torque rotation speed of the engine, the exhaust temperature in the exhaust pipe should be -L '74
It is known that by doing so, the speed of pressure transmission to the combustion chamber increases, the charging efficiency increases, and the output can be adjusted.

On the other hand, it is also known that when the ignition timing is retarded, the exhaust gas temperature decreases accordingly.

(Object of the Invention) The present invention has been made with an eye on the above-mentioned problem, and in a high rotation range, when the exhaust gas temperature in the exhaust pipe decreases, the ignition timing is retarded from a predetermined value to lower the exhaust gas temperature in the exhaust pipe. By controlling the engine to increase the ignition speed, the dynamic effect of the exhaust gas can be used efficiently. The purpose is to provide a timing control method.

(Structure of the Invention) The present invention creates and stores in advance optimum exhaust temperature data that can output the maximum torque for the engine rotation speed using a dynamic effect, reads out the optimum exhaust temperature for the engine rotation speed from the above data, and reads out the optimum exhaust temperature data for the engine rotation speed. The optimum exhaust temperature detected by the engine is compared with the exhaust temperature detected under the actual engine operating conditions, and the ignition is controlled in the rotational speed range equal to or higher than the high-torque rotational speed so that the detected exhaust temperature approaches the optimum exhaust temperature. U
) phase is retarded.

With this configuration, the exhaust gas temperature in the engine operating state is controlled so as to approach the optimum exhaust gas temperature, and the engine is operated at a maximum output of 1 to 1 lux in the above-mentioned rotational speed range.

(Example) In the drawings, 1 is a two-stroke engine, 2 is a cylinder, 3 is a screw, 4 is a crank chamber, 5 is a combustion chamber, and 6 is an exhaust pipe. The cylinder 2 has an exhaust hole 7 and an intake hole 8.
, ■ A hole 9 is provided, and the exhaust hole 7 is provided with the above-mentioned exhaust pipe 6.
is connected. This exhaust pipe 6 contains the actual engine 1.
A temperature sensor 10 is provided as a temperature detection means for detecting the exhaust temperature in the operating state of the engine. The output of this temperature sensor 1G is given to an ignition timing control device 12 via an amplifier 11.

Further, the ignition timing control device 12 is supplied with the engine rotation speed from an engine rotation speed detection unit 13 as an engine rotation speed detection means for detecting the engine rotation speed in the actual operating state of the engine 1 via an amplifier 14. . Further, the ignition timing control device 12 is equipped with a storage means for storing an optimal exhaust temperature for the engine rotation speed created in advance. The output of the ignition timing control device 12 is the output of the ignition timing control device 1
5 is given.

Here, before going into the explanation of the operation of this embodiment, the principle of this 01 work will be explained. For example, if the ignition operation of the engine 1 is performed later than a preset ignition timing, the flame kernel in the combustion air 5 will be generated later than the predetermined timing. The ignition delay 191 due to this becomes slightly shorter as the piston 3 approaches the top dead center by y7 J above the temperature in the combustion chamber 5 due to adiabatic compression of the unburned air-fuel mixture, but the combustion period becomes closer to the top dead center. From then on, it increases due to an increase in the area for cooling the gas in the combustion chamber 5 and a decrease in the rate of change in volume within the combustion chamber 5. As a result, the exhaust temperature rises above the exhaust temperature at the set rotation speed, and the sound speed increases. For this purpose, the pulsation is synchronized at a crank angle that is approximately the same as the maximum i-lux or maximum torque rotation speed of engine 1. / Therefore, the volumetric efficiency or filling efficiency can be increased, and the output can be increased.

Next, the operation of this embodiment will be explained.

The storage means of the ignition timing control device 12 stores the optimum exhaust pipe gas temperature (
Data regarding the optimum exhaust gas temperature (hereinafter referred to as the optimum exhaust temperature) is stored in advance. A curve a2 shows the characteristic of the exhaust pipe gas temperature with respect to the engine speed when the 113,1Jt tracheal cold month 1 condition is constant. Moreover, FIG. 2(b) is a characteristic diagram of torque output with respect to engine speed, and curve b1. b2 are the curves a1.b2 in FIG. 2(a) above, respectively. Characteristics obtained under conditions corresponding to a2 are shown.

Now, when the engine 1 starts and enters the operating state, the exhaust temperature signal J5 from the temperature sensor 10 and the rotational speed signal from the engine rotational speed detector 13 are filtered by amplifiers 11 and 14, and then sent to the ignition timing control device 12. is input. In addition, at the time of ignition, the control device 12 reads the optimum exhaust temperature for the input rotation speed signal from the storage means, compares the read optimum exhaust temperature with the input exhaust temperature, and determines whether this exhaust temperature is the optimum exhaust temperature. The ignition timing is set so as to approach the temperature, and the ignition device 15 is controlled by this ignition IXf period to drive the engine 1.

In other words, the engine rotation speed is the maximum torque rotation speed Nm (engine rotation speed when maximum output is generated) shown in Figure 2.
When the detected exhaust temperature corresponds to the curve (a2) and the detected exhaust temperature is higher than the optimum exhaust temperature (al), the ignition timing is advanced from the predetermined value until the exhaust temperature approaches the optimum exhaust temperature (al). I'm going to U.

This lowers the exhaust temperature, so curve b in Figure 2(b)
The torque output corresponding to 2 approaches the high torque output shown by curve b1, and the engine output increases.

On the other hand, when the engine speed is higher than the maximum torque rotation speed Nm and the detected exhaust temperature is lower than the optimum exhaust temperature (al), the ignition time 1111 is delayed from the predetermined value until the exhaust temperature approaches the optimum exhaust temperature (al). Make it corner. As a result, the exhaust gas temperature increases, approaching the high 1-lux output shown in the 1-silk force curve b], and the engine output increases.

FIG. 3 is a diagram showing the relationship between exhaust temperature and the strength of cooling of the exhaust pipe 6. Curve C1 is the characteristic when ignition timing control is performed based on the exhaust temperature of the present invention, and curve C2 is the characteristic when ignition is performed regardless of the exhaust temperature. The characteristics are shown when 11J is fixed (controlling only the engine speed). As can be seen from the figure, according to the control method of the present invention, the range of change in exhaust temperature (corresponding to curve C1) is greater than the range of change in exhaust temperature (corresponding to curve FII02) when the ignition timing is fixed regardless of the exhaust temperature. This makes it possible to prevent the exhaust pipe 6 from overheating, especially when the cooling of the exhaust pipe 6 is weak, and provides advantages in both output and thermal aspects.

(Advantage 'A' of the invention) As described above, according to the present invention, optimum exhaust temperature data that can output the maximum torque with respect to the engine rotation speed is created and stored in advance using a dynamic effect, and the engine rotation speed detected during operation is stored. At the same time as reading the optimum exhaust temperature for By controlling the R angle of the engine, it is possible to improve the output torque in the high speed range above the maximum torque rotation speed and increase the engine output.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of an ignition device for implementing the engine ignition 1.1 period control method of the present invention, and FIG.
2(b) is a characteristic diagram of torque output versus engine speed for explaining the above control method. The figure is a diagram showing the relationship between the tn air flow rate and the cooling air velocity that cools the exhaust pipe by 7 uJ. DESCRIPTION OF SYMBOLS 1... Engine, 6... Exhaust pipe, 10... Temperature sensor, 12... Ignition timing control device (including memory data), 13... Engine rotation speed detection each, 15... Ignition Device. Patent applicant: Yamaha Motor Co., Ltd. ms Figure 3 Figure 1 L
-''(''-3-j and Pi procedure number 111 official text (method) % formula % 2, Name of the invention When the engine ignites 1! IJ control method 3, Person making the amendment Relationship with the case Patent applicant name ( AO 7) ~ 7 Maha Motor Co., Ltd. 4, Agent Address: March 5, 1-10 Nishiki-cho, Nishi-ku, Osaka City, Date of Amendment Order: 1 tft, January 28, 1961 IT Map

Claims (1)

[Claims] 1. Create and store in advance optimal exhaust temperature data that can output the maximum torque for the engine speed using dynamic effects, read the optimal exhaust temperature for the engine speed from the above data, and compare this read optimal exhaust temperature with the actual The exhaust temperature is compared with the exhaust temperature detected under the engine operating condition, and the ignition timing is retarded in the rotation speed region above the maximum torque rotation speed so that the detected exhaust temperature approaches the optimum exhaust temperature. Features: Engine ignition timing control method.