JPH02201239A - Gas sampling apparatus in cylinder of engine - Google Patents

Abstract

PURPOSE:To achieve a higher sampling accuracy by branching a gas introduction tube for sampling gas into a first passage communicating with an analyzing section and a second path open to atmospheric air to open or close a solenoid valve for sampling gas and a solenoid valve for purging gas respectively in the first and second paths at a specified timing under control. CONSTITUTION:A solenoid valve 12 for sampling gas of a first path 10a communicating with an analysis section 15 is closed according to a specified sampling timing in the sampling of a gas and a solenoid valve 13 for purging gas in a second path 10b open to atmospheric air is opened to discharge a residual gas in a gas introduction tube 10 and in turn, the introduction tube 10 is filled with a gas to be analyzed. Then, after a specified delay time has passed, the solenoid valve 13 on the side of the second path 10 is closed and the solenoid valve 12 on the side of the first path 10a is opened to extract a gas sampled from a combustion chamber to the analysis section 15.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine cylinder gas sampling device, and more specifically, to an engine cylinder gas sampling device that is capable of accurately analyzing the components and concentration of cylinder gas at a specific crank angle. This invention relates to a gas sampling device.

[Conventional technology]

Generally, in order to control the ignition timing and air-fuel ratio of an engine, the exhaust gas for several cycles at a predetermined crank angle is sampled from the combustion chamber in the cylinder, and the components and concentrations in the exhaust gas are detected. , or Utsukai Showa 60-12
As shown in Japanese Patent No. 7419, prior art techniques such as a method for collecting exhaust gas samples are known.

Here, in a device that collects combustion gas from a combustion chamber in a cylinder, one end of the sampling gas introduction pipe is inserted into the combustion chamber,
It is sucked in by a pump via a sampling solenoid valve and introduced into the analysis section, but since the amount of sampling gas for one cycle at a given crank angle is usually extremely small, several cycles' worth of gas is sampled and analyzed. It is something.

[Problem to be solved by the invention]

However, in the above-mentioned prior art, there is no space for directly mounting a gas sampling solenoid valve on the cylinder head because the valve mechanism is located above the cylinder head, such as in an overhead valve type four-stroke engine. As shown in FIG. 4, a sampling solenoid valve 101 must be placed outside the cylinder head 102 of the engine, and the gas in the combustion chamber 104 must be sampled through a long gas introduction pipe 103.

Therefore, in the conventional device, the solenoid valve 101 is opened and the solenoid valve 101 is closed after completing one cycle of gas sampling at a predetermined crank angle. The gas being used at the crank angle is replaced with a gas other than the crank angle that you want to analyze, and in the next gas sampling, the previous gas inlet pipe 103
The residual gas inside will be collected in the analysis section 105.

Therefore, the gas component and concentration at a specific crank angle cannot be detected, so there is a problem that the precision of the sampling gas is poor.

The present invention was proposed to address the above-mentioned problems, and consists of branching a gas sampling gas introduction pipe at a sampling valve part, installing a solenoid valve and a pump in each of the branched passages, and It is an object of the present invention to provide an in-cylinder gas sampling device for an engine that can improve the detection accuracy of gas sampling by controlling the opening and closing of a valve at a predetermined timing.

[Means to achieve the purpose]

In order to achieve this objective, the present invention inserts one end of the gas introduction pipe for sampling gas into the combustion chamber, and installs a sampling pump at the other end to extract the gas to the analysis section via a gas sampling solenoid valve. In the gas sampling device, the gas inlet pipe for gas sampling is connected to a first passage communicating from the sampling valve part to the analysis part via the sampling pump, and a second passage communicating with the atmosphere via the purge pump. Branched out and the above 1. The gas sampling solenoid valve and the gas purge solenoid valve, which are switched and operated based on a signal from the control device, are installed in the sampling valve section of the second passage, and the gas sampling solenoid valve and the gas purge solenoid valve are connected to each other. It is characterized in that opening and closing are controlled at predetermined timings based on signals from engine crank angle detection means, sampling timing setting means, sampling time setting means, and sampling interval setting means.

[For production]

In such a configuration, the solenoid valve for gas sampling in the first passage communicating with the analysis section is closed according to the sampling timing at a predetermined crank angle set in advance during gas sampling, and the gas purge valve in the second passage on the atmosphere open side is closed. The solenoid valve opens, residual gas in the gas introduction tube is discharged by the purge pump, and the introduction tube is filled with gas at the timing for analysis.

Next, when a predetermined delay time has elapsed, the gas purge solenoid valve on the second passage side closes, and the gas sampling solenoid valve on the first passage side that communicates with the analysis section opens, and the gas sampled from the combustion chamber is sampled. A pump extracts it to the analysis section.

After the sampling time has elapsed, the gas sampling electromagnetic valve on the first passage side is closed, and sampling of the sampling gas for one cycle is completed.

As described above, according to the present invention, the necessary sampling gas can be sampled from the combustion chamber at a specific crank angle, making it possible to analyze the components and concentration of exhaust gas, allowing highly accurate exhaust gas analysis. I can do it.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing a gas sampling device in a cylinder of an engine according to an embodiment of the present invention. In the figure, the symbol l is the engine body, 2 is the crankshaft,
8 is a piston, and 4 is a cylinder head. The combustion chamber 5 of the cylinder head 4 has an intake boat 6 and an exhaust boat 7.
are in communication with the intake boat 8. An intake valve 8 is provided at the open end of the exhaust boat 7 on the combustion chamber 5 side. An exhaust valve 9 is provided.

Further, one end of a gas introduction pipe IO is communicated with the combustion chamber 5 through the cylinder head 4, and the other end of the gas introduction pipe IO is communicated with a gas sampling valve portion 1''.

The gas introduction pipe 10 in the gas sampling valve section 11 is
The first passage 10a and the second passage 10b are bifurcated, and the first passage 10a and the second passage 10b each have a gas sampling electromagnetic valve 12, which is controlled to open and close at a predetermined timing. A solenoid valve 13 for gas purge is installed.

The first passage 10a is connected to the analysis section 15 via the sampling pump 14 from the gas sampling solenoid valve 12.
The second passage 10b is open to the outside via the gas purge solenoid valve 13 and the purge pump 1B.

On the other hand, a crank angle detection sensor 17 for detecting a crank angle is installed near the crank rotor 2a of the crankshaft 2, and a crank angle signal detected by the crank angle detection sensor 17 is sent to a crank angle detection means 18.
The signal is output to the control device 20 via the .

The control device 20 includes a solenoid valve actuation timing determination section 20
a and a delay time determination section 20b, and includes a signal from the crank angle detection means 1B as well as a sampling timing setting means 21.a. Sampling time setting means 22. and reads the signal from the sampling interval setting means 23,
Gas sampling solenoid valve opening/closing means 24. Gas sampling solenoid valve 12 via gas purge solenoid valve opening/closing means 25. A signal is output to open and close the gas purge solenoid valve 13 at predetermined timing.

Here, the sampling timing setting means 21, the sampling time setting means 22. The sampling interval setting means 23 can be set to an appropriate value by manual operation, and each of the above-mentioned setting means 21.2
The output signal from 2.28 is inputted to the solenoid valve actuation timing determination section 20a of the control device 20 together with the output signal from the crank angle detection means 18.

The solenoid valve operation signal processed by the solenoid valve operation timing determining section 20a is transmitted to the gas sampling solenoid valve opening/closing means 24. The gas purge electromagnetic valve opening/closing means 25 is operated manually and is also input to the delay time determination section 20b.

The output signal from the delay time determining section 20b is inputted to the gas sampling solenoid valve opening/closing means 24 and the gas purge solenoid valve opening/closing means 25 together with the output signal from the solenoid valve operation timing determining section 20a, and the respective output signals are Gas sampling solenoid valve 12° Gas purge solenoid valve 18
and the gas sampling solenoid valve 12. The gas purge solenoid valve 13 is controlled to open and close at a predetermined timing set in accordance with a specific crank angle.

Below, the above gas sampling solenoid valve 12. The operation of the control device 20 that controls opening and closing of the gas purge electromagnetic valve 13 will be explained based on the timing chart of FIG. 2.

First, the engine body l is in an operating state, and the sampling timing setting means 2 sets the exhaust gas sampling time.
1, when the sampling time is manually set by the sampling time setting means 22 and the sampling interval is manually set by the sampling interval setting means 23, the signal detected by the crank angle detection sensor 17 at a specific crank angle The output is output from the angle detection means 18, and the sampling timing setting means 21. Sampling time setting means 22. and the output signal from the sampling interval setting means 23 as well as the solenoid valve actuation timing determining section 20a and the delay time determining section 20b of the control device 20.
is input.

Output signals of the solenoid valve operation timing determined and determined by the solenoid valve operation timing determining section 20a (for example, by a map, etc.) and the solenoid valve opening/closing time determined and determined by the delay time determining section 20b (for example, by a map, etc.) The gas sampling solenoid valve 12 . It is input to the gas purge solenoid valve 13. When the gas purge electromagnetic valve 13 opens, the gas remaining in the gas introduction pipe 10 is discharged to the outside via the purge pump 1B, and the gas remaining in the gas introduction pipe 10 is released from the combustion chamber 5 to be analyzed. Gas is introduced.

Next, after a predetermined delay time has elapsed, the gas purge solenoid valve 13 is closed and the gas sampling solenoid valve 12 is opened, and the exhaust gas just sampled from the combustion chamber 5 is passed through the sampling pump 14. The liquid is sucked and extracted into the analysis section 15.

After the sampling time set by the sampling time setting means 22 has elapsed, the gas sampling solenoid valve 12 closes to complete one cycle of gas sampling.

Here, the above delay time is such that the total flow rate Qb (hatched area χ) flowing through the second passage fob in FIG.
(Qb > Q) is determined to be larger than the volume Q (shaded area) inside.

In addition, in normal gas sampling, the amount of sampling gas for one cycle is extremely small, so it is necessary to sample the number of heart cycles, but it is possible to extract exhaust gas from the combustion chamber 5 of the cylinder for each gas sampling. This makes the operating condition of the engine unstable, so gas sampling is not performed in continuous cycles, but rather every few cycles. That is, the gas sampling interval is manually set by the sampling interval setting means 23, and the engine rotation speed is counted based on the crank angle signal, and in the case of a 4-cycle engine, two rotations of the crankshaft 2 are considered as one cycle. Gas sampling is performed at each determined sampling interval.

FIG. 3 is an explanatory diagram showing another embodiment according to the present invention,
The configuration is such that the delay time can be manually set as appropriate.

Here, the delay time setting section 20b is separated from the control device 2o, and the sampling timing setting means 21.degree. sampling time setting means 22. Sampling interval setting means 2
3, it is arranged so that it can be set manually.

Therefore, by making it possible to manually set the delay time as appropriate, it becomes possible to easily adapt to changes in the length and inner diameter of the gas introduction pipe 1o depending on the engine.

〔Effect of the invention〕

As explained above, according to the present invention, one end of the gas introduction pipe for collecting sampling gas is inserted into the combustion chamber,
In a gas sampling device, in which a sampling pump is installed at the other end to extract gas to an analysis section via a gas sampling solenoid valve, the gas sampling gas introduction pipe is connected from the sampling valve section to the analysis section via the sampling pump. The first passage is branched into a first passage that communicates with
゜In the sampling valve section of the second passage, the gas sampling solenoid valve and the gas purge solenoid valve, which are switched and operated based on a signal from the control device, are installed, and the gas sampling solenoid valve and the gas purge solenoid valve are connected to each other. , engine crank angle detection means, sampling timing setting means,
Since the configuration is configured to open and close at predetermined timings based on signals from the sampling time setting means and sampling interval setting means, gas remaining in the gas introduction pipe from the combustion chamber to the solenoid valve can be sufficiently exhausted during gas sampling. After that, the sampling gas is collected, which improves sample accuracy.

In addition, by appropriately setting the sampling timing, sampling time, and sampling interval, it is possible to sample exhaust gas at a desired crank angle and collect sampling gas for several cycles at each set sampling interval. - It is possible to improve layer sampling accuracy.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a gas sampling device showing one embodiment of the present invention, FIG. 2 is a timing chart diagram explaining the operation of the control device according to the present invention, and FIG. 3 is a gas sampling device showing another embodiment. A schematic configuration diagram of the apparatus, and FIG. 4 is a sectional view of the main parts showing a conventional embodiment. l...Engine body, 4...Cylinder head, 5.
... Combustion chamber, 11... Gas sampling valve section, 12.
... Solenoid valve for gas sampling, 13... Solenoid valve for gas purge, 14... Sampling pump, 15...
Analysis section, 1B... Purge pump, 17... Crank angle detection sensor, 18... Crank angle detection means, 20.
...Control device, 21...Sampling timing setting means, 22...Sampling time setting means, 23...
- Sampling interval setting means, 24... Solenoid valve opening/closing means for gas sampling, 25... Solenoid valve opening/closing means for gas purge.

Claims (1)

[Claims] A gas sampling system in which one end of a gas introduction tube for sampling gas sampling is inserted into a combustion chamber, and a sampling pump is installed at the other end for extracting gas to an analysis section via a gas sampling solenoid valve. In the apparatus, the gas sampling gas introduction pipe is branched into a first passage communicating from the sampling valve part to the analysis part via the sampling pump, and a second passage communicating with the atmosphere via the purge pump, 1. The gas sampling solenoid valve and gas purge solenoid valve, which are switched and operated based on a signal from the control device, are installed in the sampling valve section of the second passage, and the gas sampling solenoid valve and gas purge solenoid valve are An in-cylinder gas sampling device for an engine, characterized in that opening and closing are controlled at predetermined timings by signals from engine crank angle detection means, sampling timing setting means, sampling time setting means, and sampling interval setting means.