JP2015079006A - Exhaust gas analysis system and exhaust gas analysis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analysis system that solves problems due to stop of an engine, in exhaust gas analysis of a vehicle where the engine rotation stops while the vehicle is driven.SOLUTION: An exhaust gas analysis system includes: exhaust gas introduction piping 3 where one end of the piping is opened to an exhaust gas flow path 300 and the other end of the piping is connected to an exhaust gas analyzing device 2; and a switching mechanism 4 for selectively switching between a sampling path for sampling exhaust gas and guiding the exhaust gas to the analyzing device 2 by the exhaust gas introduction piping 3, and an atmospheric air introduction path for introducing atmospheric air and guiding the atmospheric air to the analyzing device 2, on an upstream side of the analyzing device 2. When an engine is in operation, a path to the analyzing device 2 is made to be the sampling path by the switching mechanism 4, and when the engine is stopped, the path to the analyzing device 2 is made to be the atmospheric air introduction path by the switching mechanism 4.

Description

  The present invention relates to an exhaust gas analysis system and an exhaust gas analysis method for sampling and analyzing exhaust gas from an engine (internal combustion engine).

  In recent years, with the increase of hybrid vehicles and idling stop vehicles, exhaust gas measurement of vehicles in which the engine stops during operation has been performed.

  Here, as a conventional exhaust gas analyzer, as disclosed in Patent Document 1, there is one that directly samples exhaust gas from a tail pipe through which engine exhaust gas flows and introduces the exhaust gas into the exhaust gas analyzer.

  However, when exhaust gas measurement is performed on the above-described hybrid vehicle using this exhaust gas analyzer, suction is performed by the pump of the exhaust gas analyzer even when the engine is stopped. Then, a gas flow different from the original flow occurs in the tail pipe including the engine, for example, the temperature of the catalyst provided in the tail pipe changes, or the pressure of the exhaust port of the engine decreases. There is a risk of problems such as this.

  At this time, it is conceivable to stop the measurement by stopping the pump of the exhaust gas analyzer simultaneously with the stop of the engine, but when the pump is stopped, the gas suction does not stop instantaneously due to the inertia of the pump, There is a problem that the inside of the pipe such as the tail pipe becomes negative pressure, the engine conditions change, the load of the pump of the analyzer itself is applied, or the gas flows carelessly. Further, if the pump is started at the same time as starting the engine after the pump of the exhaust gas analyzer measurement is stopped, there is a concern that the start-up delay of the pump or the like may occur.

JP 2010-139340 A

  Therefore, the main object of the present invention is to solve all the problems caused by stopping the engine at once in the exhaust gas analysis of a vehicle in which the engine rotation stops while the vehicle is operating.

  That is, in the exhaust gas analysis system according to the present invention, the exhaust gas is sampled by the exhaust gas introduction pipe having one end opened in the exhaust gas flow path through which the exhaust gas from the engine flows and the other end connected to the analytical instrument, and the exhaust gas introduction pipe. A sampling path that leads to the analysis instrument and a switching mechanism that selectively switches the atmosphere introduction path that introduces the atmosphere and leads to the analysis instrument, upstream of the analysis instrument, and the engine is stopped when the path to the analysis instrument is When the engine is switched from the operating state to the operating state, the switching mechanism is used as the sampling path, and when the engine is switched from the operating state to the stopped state, the switching mechanism is used as the air introduction path.

  In such a case, the sampling mechanism is used when the engine is operating (rotating) by the switching mechanism, and the air introduction path is used when the engine is stopped. Gas is not sucked into the exhaust gas introduction pipe from the road. Thereby, problems such as an unexpected gas flow in the exhaust gas flow path when the engine is stopped, a temperature change of the catalyst, and a pressure drop in the exhaust port can be solved. Further, since it is not necessary to stop the pump of the analytical instrument even when the engine is stopped, it is possible to solve the problems caused by the start-up when the pump is started or the inertia when the pump is stopped.

  In order to simplify and simplify the configuration of the exhaust gas analysis system and reduce the cost, the exhaust gas introduction pipe has an upstream pipe with one end opened to the exhaust gas passage. And the downstream pipe connected to the analytical instrument at the other end, the switching mechanism is connected to the upstream pipe to the first port, and the downstream pipe is connected to the second port. The third port is preferably a three-way valve opened to the atmosphere.

  In addition, in order to be able to automatically control the switching mechanism in accordance with the operation or stop of the engine, a control device that receives an engine operation related signal indicating whether or not the engine is in an operating state (rotating). However, it is desirable to control the switching mechanism.

  The exhaust gas analysis method according to the present invention also includes an exhaust gas introduction pipe having one end opened in an exhaust gas flow path through which exhaust gas from an engine flows, and the other end connected to an analytical instrument, and the exhaust gas is sampled by the exhaust gas introduction pipe. A sampling path leading to the analytical instrument and a switching mechanism for selectively switching the atmospheric introduction path leading to the analytical instrument by introducing the atmosphere are provided upstream of the analytical instrument, and the path to the analytical instrument is provided when the engine is stopped. The switching mechanism is used as the sampling path when switching to an operating state, and the atmosphere introduction path is configured using the switching mechanism when the engine is switched from an operating state to a stopped state.

  According to the present invention configured as described above, problems such as an unexpected gas flow in the exhaust gas passage when the engine is stopped, a temperature change of the catalyst, and a pressure drop in the exhaust port can be solved. In addition, since it is not necessary to stop the pump of the analytical instrument, it is possible to eliminate problems caused by rising at the time of starting the pump or inertia at the time of stopping the pump.

The figure which shows schematically the structure of the exhaust gas analysis system of this embodiment. The figure which shows the sampling path | route and atmosphere introduction path | route of the embodiment. The figure which shows the switching mechanism which concerns on deformation | transformation embodiment. The figure which shows the structure of another exhaust gas analysis system roughly.

  An embodiment of an exhaust gas analysis system according to the present invention will be described below with reference to the drawings.

  The exhaust gas analysis system 100 according to the present embodiment analyzes exhaust gas from an engine mounted on the engine dynamo 200.

  Specifically, as shown in FIG. 1, this is one end in an exhaust gas analyzer 2 which is an analytical instrument for analyzing exhaust gas of the engine E, and an exhaust gas flow path 300 through which exhaust gas of the engine E mounted on the engine dynamo 200 flows. Is opened, and the other end of the exhaust gas analyzer 3 is connected to the exhaust gas introduction pipe 3, and the exhaust gas introduction pipe 3 is provided with a sampling path L1 for sampling the exhaust gas and the air introduction for introducing the atmosphere. A switching mechanism 4 that selectively switches the path L2 and a control device 5 that controls the switching mechanism 4 are provided. The exhaust gas sampling pipe 3, the switching mechanism 4 and the control device 5 constitute an exhaust gas sampling device.

The exhaust gas analyzer 2 measures the concentration of the measurement component contained in the exhaust gas. For example, the exhaust gas analyzer 2 measures the concentration of CO, CO ₂ by the NDIR method, THC by the FID method, and NO _X by the CLD method.

  Further, in the exhaust gas passage 300, exhaust gas purification catalysts for purifying exhaust gas are provided on the upstream side and the downstream side with respect to one end opening (sampling point) of the exhaust gas introduction pipe 3, respectively.

  The switching mechanism 4 of the present embodiment is configured by a three-way solenoid valve provided in the exhaust gas introduction pipe 3. The three-way solenoid valve 4 has an upstream port (first port) P1 to which an upstream pipe 31 constituting the exhaust gas introduction pipe 3 is connected and a downstream side to which a downstream pipe 32 constituting the exhaust gas introduction pipe 3 is connected. It has a side port (second port) P2 and an air release port (third port) P3 that is open to the atmosphere. Note that the upstream opening of the upstream pipe 31 opens into the exhaust gas passage 300. Further, the downstream side of the downstream side pipe 32 is connected to the gas introduction port of the exhaust gas analyzer 2. In addition, a pipe opened to the atmosphere may be connected to the atmosphere opening port P3.

  The three-way solenoid valve 4 is controlled by a control device 5 to be described later, and as shown in FIG. 2, a sampling path L1 (see FIG. 2A) in which the upstream port P1 and the downstream port P2 communicate with each other, and the atmosphere The air introduction path L2 (see FIG. 2B) through which the open port P3 and the downstream port P2 communicate is selectively switched. The three-way solenoid valve 4 is desirably closer to the sampling point in order to improve switching responsiveness. In the present embodiment, the three-way solenoid valve 4 is provided near the outside of the pipe forming the exhaust gas passage 300 in the exhaust gas introduction pipe 3.

  The control device 5 is a dedicated or general-purpose computer including a CPU, a memory, an I / O channel, an A / D converter, etc., and the CPU and its peripheral devices cooperate in accordance with a control program stored in the memory. Thus, the three-way solenoid valve 4 as the switching mechanism is switched in accordance with the operation / stop of the engine E.

  Specifically, the control device 5 sets the sampling path L1 by controlling the three-way solenoid valve 4 when the engine E is in an operating state, and controls the three-way solenoid valve 4 when the engine E is stopped to control the atmosphere introduction path L2. And Thereby, the sample is introduced into the exhaust gas analyzer 2 when the engine E is operated (rotated), and the air is introduced into the exhaust gas analyzer 2 when the engine E is stopped.

  The control device 5 switches and controls the three-way electromagnetic valve 4 based on an engine operation related signal obtained from the engine E or a peripheral device of the engine E. The engine operation related signal is a signal indicating whether the internal combustion engine is in an operating state, that is, whether the engine E is rotating (operation (ON) / stop (OFF) of the engine E). Detection signal obtained from a pickup sensor for detecting the number of revolutions, ignition signal of engine E, engine revolution number signal obtained by analyzing vibration or noise of engine E, engine revolution number signal obtained from engine dynamo 200 as a peripheral device These are an exhaust gas flow rate signal obtained from a flow rate sensor that detects an exhaust gas flow rate flowing through the exhaust gas flow path 300, an intake flow rate signal obtained from a flow rate sensor that detects an intake air flow rate of the engine E, and the like.

  Then, the control device 5 acquires the above-mentioned engine operation related signal, determines whether or not the engine E is rotating (ON / OFF of the engine E), and when determining that the engine E is OFF. Switches the three-way solenoid valve 4 to the atmosphere introduction path L2. On the other hand, when the control device 5 determines that the engine E is ON, the control device 5 switches the three-way electromagnetic valve 4 to the sampling path L1.

  When the above signal is used as the engine operation related signal, the switching timing may be delayed with respect to the actual engine operation. In this case, a separate engine start signal may be used as the engine operation related signal. In addition, for example, when the engine E is clearly ON / OFF in the test mode section, such as an idling stop vehicle, the analysis signal obtained by analyzing the test mode is used as an engine operation related signal. It is also possible to switch the sampling path L1 / atmosphere introduction path L2 by switching the switching mechanism 4 at the timing when the engine E should be turned on / off.

  According to the exhaust gas analyzer 100 according to the present embodiment configured as described above, the three-way solenoid valve 4 is used as the sampling path L1 when the engine is operating and the air introduction path L2 when the engine is stopped. Even if it is left as it is, no gas is sucked from the exhaust gas passage 300 into the exhaust gas introduction pipe 3. Thereby, problems such as an unexpected gas flow in the exhaust gas passage 300 when the engine is stopped, a temperature change of the catalyst, and a pressure drop in the exhaust port can be solved.

  Further, since it is not necessary to stop the pump of the exhaust gas analyzer 2 even when the engine is stopped, it is possible to solve the problems caused by the start-up when the pump is started or the inertia when the pump is stopped.

  Furthermore, since the three-way solenoid valve 4 is used, not only can the configuration of the exhaust gas analyzer 100 be simplified, the cost can be reduced and the operation can be simplified.

  In addition, by providing the three-way solenoid valve 4, the exhaust gas introduction pipe 3 can be purged by causing the gas to flow backward from the exhaust gas analyzer 2 side in a warm-up mode in which the exhaust gas is not sampled. Moreover, even when the purge is required in the middle of the measurement for a long time, the purge can be performed without affecting the engine E side.

  The present invention is not limited to the above embodiment.

  The timing is important when the measurement is stopped or started when the engine is stopped or operated. In the case of the exhaust gas analysis system 100 that performs exhaust gas sampling, the delay time in which the exhaust gas flows from the sampling point to the analysis device 2 is also important for improving the accuracy of the emission calculation. Since the delay time varies depending on the type of the analytical instrument 2 and the pipe length, it is desirable to measure the delay time for each component and correct the delay time when calculating the discharge amount.

  In order to measure the delay time, for example, a standard gas having a known component concentration is supplied to the upstream opening of the exhaust gas introduction pipe, and the switching mechanism is switched to the sampling path. By comparing this switching timing with the rise timing of the instruction from the analytical instrument, the delay time at the start of measurement can be found. Similarly, the switching mechanism is switched to the atmosphere introduction path in a state where a standard gas having a known concentration is supplied. By comparing the switching timing with the falling of the instruction from the analytical instrument, the delay time when the measurement is stopped can be found. Note that the same delay time can be measured by providing the engine in a steady state and keeping the exhaust gas concentration constant without separately providing a supply mechanism for supplying a standard gas with a known component concentration.

  In the above embodiment, the switching mechanism 4 is a three-way solenoid valve, and the control device 5 acquires an engine operation-related signal and automatically switches the three-way solenoid valve 4, but the user operates the control device 5. By doing so, the three-way solenoid valve 4 may be switched.

  Further, the switching mechanism 4 may be constituted by a three-way valve so that the user can manually switch the three-way valve.

  Furthermore, although the exhaust gas analyzer of the above embodiment uses the exhaust gas analyzer 2 as an analytical instrument, other exhaust gas analyzers may be used.

  In addition, as shown in FIG. 3, the switching mechanism 4 is provided with an atmosphere opening pipe 41 branched from the exhaust gas introduction pipe 3, and provided with on-off valves 42 and 43 upstream from the branch point P, respectively. Also good.

  In addition, exhaust gas is sampled from the upstream side and the downstream side of the exhaust gas purification catalyst provided on the exhaust gas flow channel 300 using the exhaust gas analyzer 100, and the purification efficiency of the catalyst is analyzed by analyzing the sampled exhaust gas You may make it do. In this case, as shown in FIG. 4, the exhaust gas analyzer 100 includes a first exhaust gas introduction pipe 3 </ b> A that samples exhaust gas from the upstream side of the exhaust gas purification catalyst, and a second exhaust gas introduction that samples exhaust gas from the downstream side of the exhaust gas purification catalyst. A switching mechanism 4A, 4B that selectively switches between the sampling path L1 and the air introduction path L2 is provided in each of the first exhaust gas introduction pipe 3A and the second exhaust gas introduction pipe 3B.

  In addition, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Exhaust gas analysis system 300 ... Exhaust gas flow path 2 ... Exhaust gas analyzer (analytical instrument)
3 ... Exhaust gas introduction pipe L1 ... Sampling path L2 ... Atmospheric introduction path 4 ... Switching mechanism (three-way solenoid valve)
5 ... Control device

Claims (4)

An exhaust gas introduction pipe having one end opened in the exhaust gas flow path through which exhaust gas from the engine flows and the other end connected to the analytical instrument;
A sampling path for sampling the exhaust gas by the exhaust gas introduction pipe and leading to the analytical instrument and a switching mechanism for selectively switching the air introduction path for introducing the atmosphere and leading to the analytical instrument are provided upstream of the analytical instrument,
The path to the analytical instrument is the sampling path by the switching mechanism when the engine is operating, and the air introduction path by the switching mechanism when the engine is stopped.
An exhaust gas analysis system including a delay time measurement unit that measures a delay time in which exhaust gas flows from a sampling point of the exhaust gas introduction pipe to the analytical instrument.   The analysis instrument from the delay time at the start of measurement from the timing when the delay time measurement unit switches to the sampling path by the switching mechanism to the rise of the instruction of the analysis instrument, and from the timing when the switching mechanism switches to the atmosphere introduction path The exhaust gas analysis system according to claim 1, wherein a delay time at the time of measurement stop until the instruction falls is measured. An emission amount calculation unit for calculating the emission amount of the measurement component contained in the exhaust gas;
The exhaust gas analysis system according to claim 1 or 2, wherein the emission amount calculation unit performs delay time correction using the delay time obtained by the delay time measurement unit. An exhaust gas introduction pipe having one end opened in the exhaust gas flow path through which exhaust gas from the engine flows and the other end connected to the analytical instrument, and a sampling path and the atmosphere for sampling the exhaust gas through the exhaust gas introduction pipe and leading to the analytical instrument And a switching mechanism for selectively switching the air introduction path leading to the analytical instrument and upstream of the analytical instrument,
The path to the analytical instrument is the sampling path by the switching mechanism when the engine is operating, and the air introduction path by the switching mechanism when the engine is stopped,
A method for analyzing exhaust gas, comprising measuring a delay time in which exhaust gas flows from a sampling point by the exhaust gas introduction pipe to the analytical instrument.