JPS6088869A - Ignition timing control method for spark ignition engine employing optical fiber - Google Patents

Abstract

PURPOSE:To operate an engine under good combustion state by detecting the ignition timing through an optical fiber to control the ignition timing with correspondence to the time difference against the optimal ignition timing thereby matching the ignition timing with the optimal timing. CONSTITUTION:An ignition timing detector 2 will receive an engine rotation information N from a tachograph TG to calculate the optimal ignition timing while an ignition commander 5 will drive an igniter 6 with correspondence to a signal from a crank angle detector CAD to discharge through an ignition plug P. The condition of flare is detected by a light receiving section OD at the end of optical fiber OF and a firing detector 1 will detect the start-of-firing information through an inflared timing difference detector OE. A firing timing difference detector 4 will calculate the time difference from the start-of-firing information and the optimal firing timing, then said time difference is corrected at the ignition timing corrector 3 and provided to a ignition commander 5. In such a manner, the engine can be operated continuously with the optimal firing timing.

Description

[Detailed Description of the Invention] It is widely known that in order to achieve proper combustion in a spark-ignition engine, it is necessary to ignite the spark so that the timing of starting the ignition of the fuel matches the optimum position in terms of the crank angle. ing. However, since it is difficult to directly detect the actual timing of ignition in a high-temperature, high-pressure combustion chamber, in many cases the timing of fuel ignition is assumed to be the same as the ignition timing, or the delay until ignition is assumed to be constant. The ignition timing is controlled by an advance device or the like so that the ignition start timing is at an appropriate value. However, the ignition delay, which is assumed to be zero or constant here, actually changes in a variety of ways depending on the environment inside the fuel chamber and injection conditions, so with this type of control, the ignition start timing may not necessarily be set to the appropriate value in all modes. It doesn't necessarily have to be set.

The applicant has recently succeeded in detecting the ignition start timing and combustion status in the combustion chamber by inserting a heat-resistant optical fiber through the partition wall of the combustion chamber of a high-temperature, high-pressure reciprocating internal combustion engine. The high-temperature gas generated as a result of combustion in the combustion chamber is a flame image with brightness, and it also emits high-level infrared rays. This is because the timing of starting ignition can be easily detected by propagating the flame image or infrared rays to the outside, providing a known element for detecting the flame image or infrared rays at the other end of the optical fiber, and converting the flame image or infrared rays electrically.

The optical fiber used here is a well-known so-called S-type fiber, in which the outer periphery of the core is coated with a cladding, or a G-type fiber.
Generally, it is considered to use an optical fiber, but if the length of the optical fiber is short and the fiber is not used with bending or lateral loads, the light The cross section of the fiber is approximately /~3m
A known rod lens made of a known elongated heat-resistant glass bale of about mfl, or a elongated heat-resistant glass bale that also has a light-concentrating function with the light receiving end as the tip of the glass or the light receiving element connection end being a curved surface. Alternatively, a drum lens or the like may be used.

The spectrum of infrared rays emitted by combustion gas changes depending on the temperature of the combustion gas, so select the type of infrared receiving element C (hereinafter referred to as "element") or install the required infrared filter in front of the element. By doing so, it is also possible to set the main wavelength of infrared rays to be detected, that is, the temperature of the combustion gas. Therefore, for example, it is possible to select whether to detect the period when the combustion gas temperature is relatively low immediately after the start of combustion, or whether to detect the period when combustion has expanded and high-temperature gas is generated by selecting the above-mentioned means. It is.

On the other hand, the position at which the ignition start timing of the fuel should match in terms of crank angle in order to obtain a good combustion condition depends on the state of combustion at the ignition start timing to be matched. For example, if the above-mentioned means detects the time when the combustion gas is low immediately after the start of combustion as the ignition start time, and this detection time is matched to the optimum position by looking at the crank angle, then the ignition start time may be just before the end of the combustion or when the combustion has ended. (detection at this time is when the flame image disappears,
Alternatively, the moment when the level of infrared rays of a specific wavelength decreases can be regarded as such. ] If we match that timing to the optimal position, that position will be far behind top dead center.

In this way, by detecting the actual ignition start timing and changing the ignition timing, this timing is matched to the optimum position in terms of crank angle, thereby matching the control position to obtain the best combustion condition. The desired position will vary depending on the content of the combustion to be detected.

However, immediately after the fuel ignites, the combustion gas is in a low temperature state, and it is not only the time when the ignition starts in the true sense.
JP-A-Sho GO-8886 ignites when combustion has progressed considerably.
9 (3) Even if the detection is performed with the timing considered as the start time, if control is implemented to change the start time of the spark salvo so that it matches the optimal position according to the detected time, it is still possible to achieve the best result. Combustion control can be performed in this state.

The feature of the present invention is that, in a broad sense, the ignition start timing C
The purpose of this is to detect the ignition timing (hereinafter referred to as ignition timing) using an optical fiber, and to operate the engine in a state where the ignition timing thus detected and the ignition timing are the ideal ignition timing.

Next, one embodiment of the present invention will be described based on the block diagram shown in FIG. In the figure, the light receiving part OD at the tip of the heat-resistant optical fiber OF installed through the partition wall of the combustion chamber OO, where fuel supplied for each stroke from the fuel supply device (not shown) of the engine IN is combusted, is connected to the combustion chamber aO. They are installed at locations where it is easy to detect flame outbreaks inside the building.

It has the function of converting the infrared rays of more than 200 yen to a light level by known means, and converts the infrared rays inputted from the optical fiber O-E into an electrical signal and outputs it to the ignition detector 1. . Ignition detector with built-in known amplifier and comparator/
When the electric signal is output from the element OK, the level reaches a certain value and the operation is stopped.
Ignition start information indicating that combustion in the combustion chamber has reached a certain predetermined level is output to the ignition point detector. In this embodiment, as a means of detecting that combustion has reached a certain level, infrared rays of a specific wavelength emitted from the combustion gas in the combustion chamber aC are used to connect optical fibers with other means to detect when the combustion has progressed to a certain level. It is also possible to use a light receiving element to capture the flame image made up of visible light that is being generated.In short, depending on the combustion level to be detected, the wavelength of the light to be detected and the corresponding specifications of the element as a detection means are determined. It will be determined.

The ignition timing detector consisting of a known bang generator is engine K.
Engine speed information from tachometer TG directly connected to N
is input, the optimum fuel ignition timing is detected based on the rotation speed in terms of the crank angle, and this is output to the ignition command unit 5 via the ignition time difference detector and the ignition time difference corrector 3, which has a function to be described later. do. In addition to the above-mentioned output, output information from a crank angle detector CAD that detects the crank angle of the engine is sequentially input to the ignition command device S having a known comparator.
These two pieces of information are compared by a known means using a built-in comparator, and when the sequentially input crank angle position information matches the optimum ignition timing information, that is, the engine crank angle is at the optimum position according to its rotation speed. When the ignition timing matches the ignition timing of the
Ignite the fuel in the condenser and combustion chamber OO.

Under these circumstances, the ignition time difference detector 1, which inputs the ignition start information indicating that the combustion in the combustion chamber OC has reached a certain level, also receives the optimal ignition timing information from the ignition timing detector 2, which is also input. , and the difference in crank angle between the ignition start information and the optimal ignition information, that is, the difference between the optimal ignition position and the actual ignition timing, based on the crank angle position information sequentially output from the crank angle detector OAD. The publicly known command will be revised accordingly. The command of the ignition controller S is corrected using a method similar to that of a cam, so that the combustion of 4 oa is constantly carried out at the optimum timing, eliminating the influence of many factors that change the combustion start timing. This allows the engine to operate in a good combustion state.

In this embodiment, an example has been described in which the ignition time difference is corrected based on the crank angle, but a method of detecting the time difference and correcting it based on time may also be considered. However, this method also depends on the difference between the actual ignition timing and the optimal timing.
Since the idea of correcting and controlling the spark ignition timing is the same as the method described above, the configuration can be made much simpler. On the contrary, the optimum timing depends not only on the rotation speed but also on other variable factors,
For example, p may vary depending on the combustion supply value, or may also vary depending on other additional factors such as intake air temperature. In such cases, it is possible to take measures such as creating multiple bangs or multiple bang group generators in advance according to those factors, and to take storage means that can detect the optimal timing according to the factor group. good.

FIG. 2 shows an example in which a known multiple bang group generator is used as means for detecting the optimum ignition timing when one factor as described above is added. In the figure, a group of buttons is selected according to temperature information t1 from an intake temperature sensor (not shown) and fuel supply information t from a fuel supply device (also not shown), and the thus selected QI, Q2, Qs...
Depending on the amount of fuel supplied. Among the <tans group, select the only << tongue according to the input fuel supply information Q, and detect the optimum ignition timing using the same method as the collation shown in Fig. 1. and output to the ignition timing corrector 3, eliminating the influence of many factors,
The engine can always be operated in good condition with optimal ignition timing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 1 is a concept of a pattern generator showing an embodiment of an optimum ignition timing detection means when the optimum ignition timing is influenced by many factors. It is a diagram. IN...engine, 00...combustion chamber, P...spark plug, T()...tachometer, OAD...crank angle detector, OF...optical fiber, OD...light receiving Department, OE
···element,! ...Ignition detector, K...Ignition timing detector, 3...Ignition timing corrector, D...Ignition time difference detector, S...Ignition command device, 6...Ignition device designation agent Person Mr. Tatsuzo Honma, Legal Affairs Division, Office of the President of Japanese National Railways

Claims (1)

[Scope of Claims] /) In an ignition control device for a spark ignition engine, in order to optimally maintain the ignition timing of fuel, a flame image received by a light receiving end in the combustion chamber of an optical fiber that has passed through the partition wall of the combustion chamber is used. The ignition timing of the fuel is detected by propagating it to the outside of the combustion chamber, and the ignition timing is optimized by correcting and controlling the spark ignition timing according to the difference between the detected ignition timing and the optimum ignition timing of the spark ignition engine. Match the ignition timing,
A fuel ignition timing control method for a spark ignition engine using an optical fiber, which is characterized by operating the engine in a good combustion state. , 2) Thick silicon as described in the light receiving section at the light receiving end in the combustion chamber of the optical fiber. In the ignition control system of a spark ignition engine, in order to maintain the optimal ignition timing of the fuel, a flame image received by the light receiving end inside the combustion chamber of an optical fiber that penetrates the partition wall of the combustion chamber is propagated to the outside of the combustion chamber. When the ignition timing of combustion is detected by , and the ignition timing of the fuel is made to match the optimum ignition timing by correcting and controlling the 1-spark ignition timing according to the difference between the ignition timing thus detected and the optimum ignition timing of the engine,
When the optimum ignition timing is determined according to the engine rotation speed, the optimum ignition timing information obtained by inputting the engine rotation speed into a storage device that previously stores the optimum ignition timing according to the factor is used. In order to optimally maintain the ignition timing of the operating charge in the best combustion state according to the engine rotation speed, the flame image received at the light receiving end in the combustion chamber of the optical core that penetrates the partition wall of the combustion chamber is burned. -When the ignition timing of the fuel is matched with the optimum ignition timing by passing the fuel outside the combustion chamber, a mechanism is used to set the optimum ignition timing, thereby operating the engine in the best combustion state according to the engine speed +d. The second claim is characterized in that it is a spark ignition engine using an optical fiber.