JP2010007532A - Scavenging controller of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scavenging controller for a vehicle capable of favorably suppressing worsening of the exhaust emission by conducting the scavenging of the exhaust passage efficiently and effectively. <P>SOLUTION: In the vehicle 10 having an engine 200 including an exhaust pipe 215 furnished with an S/C catalyst 216 and an O<SB>2</SB>sensor 218 for controlling the air fuel ratio F/B of the fuel injection amount and arranged at the downstream of the S/C catalyst, an ECU 100 executes the scavenging control. In the scavenging control, a forced motoring is started by supplying a driving force from a starter 400 when ignition is put off. The forced motoring forms a suction flow directed from a suction pipe 207 to the exhaust pipe 215, and scavenging is accomplished. On the other hand, determination of the completion of scavenging is passed on the basis of the output voltage Vox of the O<SB>2</SB>sensor 218. That is, the ECU 100 determines that the area around the O<SB>2</SB>sensor 218 is substituted with atmosphere and the scavenging is completed, in case the sensor output voltage Vox has sunk to the atmospheric equivalent value Voxair or below, and the ECU stops the forced motoring and ends the scavenging control. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of a scavenging control device for a vehicle capable of scavenging an exhaust passage of an internal combustion engine.

  As this type of device, one that performs scavenging when the engine is stopped has been proposed (see, for example, Patent Document 1). According to the engine stop control device disclosed in Patent Document 1, when an engine stop operation is performed, the ISC valve is fully opened, and the engine stop control is performed after increasing the engine rotation speed. It is said that the next engine start can be performed satisfactorily because the number of pumping operations can be increased and the burned gas in the intake pipe, the combustion chamber and the exhaust pipe can be scavenged.

  In addition, based on the oxygen concentration on the upstream side of the catalyst and the oxygen concentration on the downstream side of the catalyst, the presence or absence of backflow of exhaust gas at the time of engine stop is determined. A technique for scavenging has also been proposed (see, for example, Patent Document 2).

  Further, in scavenging control performed when the engine is stopped, a technique is also disclosed in which, when it is detected that excess exhaust gas has passed, a bypass pipe is passed through the exhaust gas by an exhaust gas switching valve (see, for example, Patent Document 3). ).

JP 2002-54469 A JP 2007-239570 A JP 2008-2376 A

  When the internal combustion engine is stopped, burned gas or unburned gas containing unburned fuel remains in the combustion chamber and the exhaust pipe. Residual substances such as HC contained in the residual gas are, for example, at detection terminals and the like in various sensors such as an air-fuel ratio sensor and an oxygen concentration sensor installed in the exhaust passage during the engine stop period of the internal combustion engine. May adhere, adsorb or stick. Thus, in the state where the residual substance is adhered, adsorbed or fixed, the detection accuracy of the air-fuel ratio and oxygen concentration by these various sensors is remarkably lowered, and the air-fuel ratio feedback control at the next start is affected. More specifically, the convergence of the air-fuel ratio to the target air-fuel ratio is delayed because the air-fuel ratio is greatly shifted to the rich side (oxygen-deficient side, that is, fuel-excess side). Such a delay in convergence makes the deterioration of the emission due to the fact that the fuel injection amount is not optimized become obvious, and becomes a serious problem at the start-up when the emission tends to deteriorate relatively.

  Here, as shown in Patent Document 2, if scavenging is performed at the time of start-up, there is a high possibility that unburned fuel or the like is already considerably adhered, adsorbed, or stuck to various sensors. The time required to reduce the shift to the rich side to a level that does not cause a problem in practice becomes longer, and the above-described emission tends to deteriorate during that time.

  Further, in the technique described in Patent Document 3, scavenging is terminated when the crankshaft rotates 10 times from the start of scavenging, but at this stage, even if this kind of termination condition is set due to prior adaptation. It is completely unknown whether or not the unburned fuel in the exhaust pipe has actually been wiped out, and there is no guarantee that adhesion, adsorption or sticking of residual substances to the detection means can be reliably avoided.

  Further, as disclosed in Patent Document 1, when the rotational speed is temporarily increased at the time of stopping to increase the number of pumping operations due to inertia, scavenging can proceed as compared with the case where the rotational speed is not increased, but as expected. Is merely scavenging by inertia due to inertial force, and the rotational speed of pumping gradually attenuates, and scavenging is not always sufficiently performed. Further, when the inertial force is used in this way, the scavenging end timing can be changed each time according to the engine speed when the engine is stopped, the friction of the internal combustion engine, etc., and it is difficult to stably obtain the scavenging effect. . In particular, scavenging using such inertial force, when a catalyst device is provided in the exhaust passage, is easily affected by the pressure loss generated in the catalyst device, and the exhaust flow velocity is attenuated by the pressure loss. It is difficult to proceed downstream of the apparatus. For this reason, it is difficult to avoid adhesion, adsorption or sticking of residual substances in various sensors installed downstream of the catalyst device.

  As described above, the various conventional techniques have a technical problem that it is difficult to avoid deterioration of emission at the time of starting.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine that can efficiently and effectively scavenge an exhaust passage.

  In order to solve the above-described problem, a scavenging control device for a vehicle according to the present invention includes an internal combustion engine having a detecting means capable of detecting an oxygen concentration in an exhaust passage, and a scavenging means capable of scavenging the exhaust passage. A scavenging control device for a vehicle, wherein the scavenging control means controls the scavenging means so that the scavenging is started when the engine of the internal combustion engine is stopped, and whether the scavenging is completed based on the detected oxygen concentration Determining means for determining whether or not the scavenging control means controls the scavenging means so that the scavenging is completed when it is determined that the scavenging is completed.

The “internal combustion engine” according to the present invention includes at least one cylinder, and in each of the cylinders, various fuels such as gasoline, light oil, alcohol, or a mixture of the alcohol and gasoline are combusted (preferably, fuel). An engine configured to be able to take out the power generated when the air-fuel mixture burns) as the driving force of the vehicle through various physical and mechanical transmission paths such as pistons, connecting rods, and crankshafts. It is a concept that encompasses at least a system in which auxiliary machinery including, for example, various sensors, various catalytic devices, and the like according to various applications can be appropriately attached to this type of engine. In particular, the internal combustion engine according to the present invention is provided with detection means such as an oxygen concentration sensor (O ₂ sensor) or an air-fuel ratio sensor that can detect the oxygen concentration in the exhaust passage in the exhaust passage.

  The “scavenging” according to the present invention means that the internal combustion engine is physically supplied (that is, supplied from the outside) without fuel injection and combustion for the purpose of purifying the site to be scavenged (that is, the exhaust passage here). To generate a gas flow from the intake passage to the exhaust passage. Therefore, the “scavenging means” according to the present invention refers to rotating the engine output shaft, whether directly or indirectly, with respect to the engine output shaft of the internal combustion engine (a crankshaft as a preferred embodiment). It is a concept encompassing physical, mechanical, electrical, or magnetic means capable of supplying a driving force to be obtained, and as a preferred form, for example, an electric motor such as a motor mainly installed for scavenging, or mainly A starting device or the like installed for cranking at the time of starting. Alternatively, in the case of a hybrid vehicle provided with various electric motors such as a motor or a motor generator in addition to the internal combustion engine as a driving force source, the scavenging means may be an electric motor that can function as these power sources.

  According to the scavenging control device for a vehicle according to the present invention, during operation, scavenging that can take the form of various processing units such as an ECU (Electronic Control Unit), various controllers, various computer systems such as a microcomputer device, or the like. The scavenging means is controlled by the control means so that scavenging is performed when the engine of the internal combustion engine is stopped.

  Here, in the exhaust passage, as described above, various physical quantities and index values correlated with the oxygen concentration, such as an air-fuel ratio sensor and an oxygen concentration sensor, directly or indirectly (for example, voltage value, current value, etc.). Detection means that can detect the oxygen concentration, the detection result is the so-called fuel air-fuel ratio feedback control (hereinafter referred to as fuel air-fuel ratio feedback control) for following or converging the air-fuel ratio to the target air-fuel ratio. This is used for various operation control of the internal combustion engine including “air-fuel ratio F / B” as appropriate. At this time, at least a part of the detection terminal for detecting the oxygen concentration in this detecting means is exposed to at least the atmosphere in the exhaust passage, whether or not it is exposed in the exhaust passage.

  Therefore, when the exhaust passage is scavenged when the internal combustion engine is started, the unburned gas or the unburned fuel (for example, HC) is included in the elapsed time from the time when the internal combustion engine was last stopped until the start time. As a result of exposure to gas, residual substances such as HC may adhere, adsorb or adhere to the detection terminal. In particular, HC is somewhat sticky due to SOF and the like in the fuel, and this type of problem is likely to occur.

  In this way, when the residual substance in the exhaust passage adheres, adsorbs or adheres to the detection terminal, the oxygen concentration detected by the detection means tends to be lower than the actual oxygen concentration, and is detected or detected. The air-fuel ratio specified based on the oxygen concentration is likely to shift to a richer side than the actual air-fuel ratio. Alternatively, the feedback control term calculated based on the detected oxygen concentration tends to be inappropriate. For this reason, when the exhaust passage is scavenged at the time of starting, the fuel injection amount is controlled based on the air-fuel ratio shifted to the rich side in this way, or the feedback control of the fuel injection amount based on an inappropriate feedback control term is performed. As a result, the time until the air-fuel ratio converges to the target air-fuel ratio becomes longer, and the emission is likely to deteriorate. Such worsening of emissions due to scavenging at start-up is not reduced at least so that they are offset, for example, when attempting to eliminate the effects of this type of residual material on the software.

  On the other hand, when the exhaust passage is scavenged when the engine is stopped, the residual material in the exhaust passage decreases somewhat before the start-up in view of the concept of scavenging. Adhesion, adsorption or sticking can be suppressed. For this reason, it is possible to shorten the time until the air-fuel ratio converges to the target air-fuel ratio as much as possible compared with the case where scavenging is performed at the time of starting, and the air-fuel ratio F / B control at the time of starting is made more efficient. It is possible to execute well, and it is possible to suitably suppress the deterioration of emission.

  On the other hand, the scavenging means does not change in that any energy resource is used regardless of any physical, mechanical, electrical, or magnetic configuration, and in particular, the power stored in the vehicle battery, etc. When energy resources with a high request frequency and an insufficient amount of storage are used, at least from the viewpoint of effective use of energy resources, the scavenging time (the time for scavenging is the length of the scavenging period) (Some) is shorter. On the other hand, if the scavenging time is inadequate, the emission may deteriorate at the start as described above. From a practical point of view, as a consideration on the safety side arising from a request to avoid the emission deterioration. The scavenging time tends to become unnecessarily long.

  Here, in particular, when the scavenging time is set in advance regardless of whether the options are singular or plural, a new problem such as wasteful consumption of energy resources due to scavenging becomes apparent as something to be avoided or suppressed.

  At this time, if the scavenging time is set so that the scavenging time can be shortened as much as possible after ensuring that scavenging is completed in advance, the physical state or chemical state inside the exhaust passage However, without any guidance on how the internal combustion engine has changed over time, no solution can be obtained.

  Therefore, according to the scavenging control device for a vehicle according to the present invention, the operation is detected by a discriminating means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. It is determined whether scavenging has been completed based on the oxygen concentration. In addition, when it is determined by the determining means that scavenging has been completed, scavenging is terminated through drive control of the scavenging means by the scavenging control means.

  The deterioration of the emission at the time of starting is remarkably caused by the fact that residual substances (especially unburned fuel) in the exhaust passage adhere to, adsorb, or adhere to the detection means during the engine stop period (period from the engine stop time to the start time). Generated by sticking. Therefore, if there is no residual substance in the exhaust passage, it is possible to avoid this type of emission deterioration regardless of the length of the engine stop period.

  Here, when external air is sucked in by scavenging and a flow of intake air from the intake passage to the exhaust passage is generated, residual substances in the exhaust are gradually expelled from the exhaust passage by the intake air. Therefore, the oxygen concentration in the exhaust passage corresponds one-to-one, one-to-many, many-to-one, or many-to-many with the degree of residual substances remaining in the exhaust passage when the engine is stopped. That is, it is possible to accurately determine whether scavenging has been completed based on the specified oxygen concentration. In qualitative terms, scavenging is more advanced as the oxygen concentration is higher.

  Note that “the scavenging has been completed” means that the detection result is provided in the exhaust passage as the detection result can be used for air-fuel ratio F / B control when the internal combustion engine is started after an engine stop period within a range that can be assumed in advance. It means that the state of the exhaust passage, which is estimated or determined to have no residual substance attached, adsorbed or adhered to the means, at least not practically overlooked, is obtained. Such a criterion for determining the completion of scavenging (that is, a criterion for determining whether or not the exhaust passage state has been obtained) is appropriately set according to, for example, the environmental performance required for the internal combustion engine. It may be set regardless of this type of required performance.

  As described above, according to the scavenging control device for a vehicle according to the present invention, the scavenging at the time of stopping the engine suppresses the deterioration of the emission that may occur at the next start at least within an allowable value (as a preferred form, at least this kind (Including not causing deterioration of emissions) in as short a time as possible. For this reason, the energy resource for driving the scavenging means can be utilized as efficiently as possible. That is, scavenging can be realized efficiently and effectively.

  Supplementally, the control device for an internal combustion engine according to the present invention is extremely effective in determining whether or not scavenging can be terminated by considering the state of the exhaust passage or the state of the detection means provided in the exhaust passage at that time. For example, based on the execution time or the number of execution cycles as a fixed value or variable value, which has been adapted in advance, the exhaust passage or detection at that point in time is made. Unlike the technical idea of scavenging without considering the state of the means at all, the essence is different. Compared with such a technical idea, the deterioration of emissions at the next start-up is reliably suppressed, and at the same time It has a significant advantage in that it can reliably suppress wasteful consumption of resources.

  In one aspect of the scavenging control apparatus for a vehicle according to the present invention, the determining means determines that the scavenging is completed when the detected oxygen concentration corresponds to an oxygen concentration in the atmosphere.

  When the detected oxygen concentration corresponds to the oxygen concentration in the atmosphere, it can be determined that the exhaust passage is substantially filled with the atmosphere, assuming that the gas distribution in the exhaust passage is uniform or substantially uniform. Therefore, in this case, it is easy to make a determination that the possibility that the residual substance adheres, adsorbs or adheres to the detection means is extremely low, and it is possible to accurately determine the scavenging completion.

  At this time, the oxygen concentration in the atmosphere is fixed or variable in accordance with the ambient temperature and humidity around the vehicle, the altitude and the absolute position of the vehicle, etc. in advance experimentally, empirically, theoretically, or based on simulation. For example, it may be stored as an oxygen concentration in fuel cut control (hereinafter referred to as “F / C control” or the like as appropriate) performed during deceleration.

  In another aspect of the vehicle scavenging control apparatus according to the present invention, the internal combustion engine includes a catalyst device capable of purifying exhaust gas upstream of the detection means in the exhaust passage.

  According to this aspect, the upstream side of the detection means in the exhaust passage of the internal combustion engine (note that “upstream” is a directional concept based on the gas flow direction. In the exhaust passage, that is, on the exhaust valve side. For example, a three-way catalyst, an NSR (NOx storage reduction catalyst), or an oxidation catalyst (including capture and regeneration means such as DPF carrying an oxidation catalyst) is provided.

  At this time, as long as at least a part of the detection means is arranged on the downstream side of the catalyst device, a part of the detection means may be arranged on the upstream side of the catalyst device. That is, for example, an aspect in which an air-fuel ratio sensor is disposed on the upstream side and an oxygen concentration sensor is disposed on the downstream side across the catalyst device is also included in this aspect.

  In such a configuration, an increase in exhaust resistance (that is, an increase in pressure loss) in the catalyst device tends to hinder the progress of scavenging of the detection means on the downstream side of the catalyst device. Therefore, it is more difficult to determine whether or not scavenging has been completed, and the practical advantage of the determination unit according to the present invention is significantly increased.

  In view of the fact that the pressure loss can be somewhat increased by the catalyst device and the scavenging can be inhibited, even if other detection means (for example, an air-fuel ratio sensor) is disposed upstream of the catalyst device, The peripheral part of the detection means is purified earlier than the peripheral part of the detection means on the downstream side of the catalyst device. Therefore, as long as the scavenging completion determination is made based on the oxygen concentration detected by the detection means on the downstream side of the catalyst device, it is necessary to consider the attachment, adsorption or sticking of the residual substance on the detection means on the upstream side of the catalyst device. Does not occur.

  In one aspect of the vehicle scavenging control apparatus according to the present invention, in which the internal combustion engine includes a catalyst device and a detection unit, the internal combustion engine includes a section corresponding to the upstream side of the catalyst device in the exhaust passage, and the exhaust passage. A first communication passage that communicates a section corresponding to the downstream side of the catalyst device and the upstream side of the detection means without passing through the catalyst device; and the first communication passage is installed in the first communication passage, And a scavenging control device for the vehicle, wherein the scavenging control device of the vehicle is configured so that the gas is guided to the first communication passage during a scavenging period in which the scavenging is performed. First flow rate control means for controlling the first flow rate adjustment means is further provided.

  According to this aspect, the section corresponding to the upstream side of the catalyst device and the section corresponding to the downstream side of the catalyst device and the upstream side of the detection means are communicated by the first communication path without passing through the catalyst device. That is, the first communication passage is configured as a kind of bypass passage. In the first communication path, for example, a first flow rate adjusting unit that can take the form of various valve devices (including a valve body driving unit) such as an electromagnetic on-off valve and a butterfly valve is disposed, For example, by the drive control by the first flow rate control means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device, for example, the opening / closing state of the valve body is binary, stepwise or By being controlled continuously, the flow rate of the gas in the first communication path (a gas including at least intake air and preferably the intake air itself) is binary, stepwise, or continuous. It is configured to be adjustable.

  Here, the first flow rate control means controls the first flow rate adjustment means so that the gas is guided to the exhaust passage through the first communication path and bypasses the catalyst device during the scavenging period. At this time, the flow rate of the gas in the first communication path is not particularly limited as long as it is not zero. However, as a preferred embodiment, the first flow rate adjusting means is a valve device, and its valve body is position-controlled fully open. The gas corresponding to the maximum flow rate that can be realized at that time may bypass the catalyst device and be led to the exhaust passage. In addition, assuming that the gas is guided to the first communication path in this way, it is not necessary to close the normal scavenging path (that is, the path reaching the exhaust passage around the detection means via the catalyst device), and the scavenging process In this case, the gas discharged from the combustion chamber may be divided into a path through the catalyst device and the first communication path.

  According to this aspect, at least a part of the gas used for scavenging is led to the section where the detection means is installed in a form that bypasses the catalyst device. For this reason, it becomes possible to remove residual substances as quickly as possible from the periphery of the detection means, and it is possible to finish scavenging earlier (that is, to determine scavenging completion at an earlier time point). As a result, the energy resources can be used more effectively.

  In another aspect of the vehicle scavenging control apparatus according to the present invention, in which the internal combustion engine includes a catalyst device and detection means, the internal combustion engine is located downstream of the catalyst device and upstream of the detection means in the intake passage and the exhaust passage. A second communication passage that communicates a section corresponding to the second communication passage without passing through the combustion chamber, and a second flow rate adjustment that is installed in the second communication passage and that can adjust the gas flow rate in the second communication passage. And a scavenging control device for controlling the second flow rate adjusting means to control the second flow rate adjusting means so that the gas is guided to the second communication path during the scavenging period in which the scavenging is performed. Means are further provided.

  According to this aspect, the intake passage and the section corresponding to the downstream side of the catalytic device and the upstream side of the detecting means are communicated by the second communication passage without going through the combustion chamber (necessarily without going through the catalytic device). It is done. That is, the second communication passage is configured as a kind of bypass passage. In the second communication path, for example, a second flow rate adjusting unit that can take the form of various valve devices (including a valve body driving unit) such as an electromagnetic on-off valve and a butterfly valve is disposed. For example, by the drive control by the second flow rate control means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device, for example, the open / close state of the valve body is binary, stepwise or By being controlled continuously, the flow rate of the gas in the first communication path (a gas including at least intake air and preferably the intake air itself) is binary, stepwise, or continuous. It is configured to be adjustable.

  Here, the second flow rate control means controls the second flow rate adjustment means so that the gas is guided to the exhaust passage through the second communication path and bypasses the combustion chamber and the catalyst device during the scavenging period. To do. At this time, the flow rate of the gas in the second communication path is not particularly limited as long as it is not zero. However, as a preferred form, the second flow rate adjusting means is a valve device, and its valve body is position-controlled fully open. The gas corresponding to the maximum flow rate that can be realized at that time may be guided to the exhaust passage bypassing the combustion chamber and the catalyst device. It should be noted that the normal scavenging path (that is, the path reaching the exhaust passage around the detection means via the combustion chamber and the catalyst device) does not need to be closed as the gas is guided to the second communication path in this way. The gas guided to the intake passage during the scavenging process may be divided into a path through the combustion chamber and the second communication path.

  According to this aspect, at least a part of the gas used for scavenging is led to the section where the detection means is installed in a form bypassing the combustion chamber and the catalyst device. For this reason, it becomes possible to remove residual substances as quickly as possible from the periphery of the detection means, and it is possible to finish scavenging earlier (that is, to determine scavenging completion at an earlier time point). As a result, the energy resources can be used more effectively.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment of the Invention>
Various preferred embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the vehicle 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram conceptually showing a configuration of a portion related to the “vehicle scavenging control device” according to the present invention in the vehicle 10.

  In FIG. 1, a vehicle 10 is an example of a “vehicle” according to the present invention that includes an ECU 100, an engine 200, an ignition key (hereinafter simply referred to as “IG key”) 300, a starter 400, and a battery 500.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM, and the like and is configured to be able to control the entire operation of the hybrid vehicle 10. Is an example of a “scavenging control device”. The ECU 100 is configured to execute scavenging control to be described later according to a control program stored in the ROM.

  The ECU 100 is an integrated electronic control unit that functions as an example of each of the “scavenging control means” and the “discriminating means” according to the present invention. The configuration is not limited to this, and may be configured as various computer systems such as a plurality of ECUs, various processing units, various controllers, or a microcomputer device.

  The engine 200 is a gasoline engine as an example of the “internal combustion engine” according to the present invention.

  Here, the configuration of the engine 200 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram conceptually showing the configuration of the engine 200.

  In FIG. 2, an engine 200 burns an air-fuel mixture through an ignition operation by an ignition device 202 in which a part of a spark plug (not shown) is exposed in a combustion chamber in a cylinder 201, and an explosive force due to such combustion. The reciprocating motion of the piston 203 that occurs in response to the above is converted into the rotational motion of the crankshaft 205 via the connecting rod 204. A crank position sensor 206 that detects the rotational position (ie, crank angle) of the crankshaft 205 is installed in the vicinity of the crankshaft 205. The engine 200 is an in-line four-cylinder engine in which four cylinders 201 are arranged in series in a direction perpendicular to the paper surface. However, since the configurations of the individual cylinders 201 are equal to each other, in FIG. Only the cylinder 201 will be described.

  In the engine 200, the air sucked from the outside passes through the intake pipe 207 and is mixed with the fuel injected from the injector 212 in the intake port 210 to become the above-mentioned air-fuel mixture. The fuel is stored in a fuel tank (not shown), and is pumped and supplied to the injector 212 via a delivery pipe (not shown) by the action of a feed pump (not shown). The form of the injection means for injecting the fuel does not have to adopt a so-called intake port injector configuration as shown in the figure. For example, the pressure of fuel pumped by a feed pump or other low-pressure pump is further increased by a high-pressure pump. It may have a form such as a so-called direct injection injector configured to be able to directly inject fuel into the high-temperature and high-pressure cylinder 201. In this embodiment, the fuel stored in the fuel tank and injected from the injector 212 is gasoline. However, the “internal combustion engine” according to the present invention is, for example, a compression self-ignition diesel that can use light oil as fuel. It may be an engine, or a bi-fuel engine that can use alcohol such as ethanol or a mixed fuel of the alcohol and gasoline as fuel.

  The communication state between the inside of the cylinder 201 and the intake pipe 207 is controlled by opening and closing the intake valve 211. The air-fuel mixture combusted inside the cylinder 201 becomes exhaust, and when the exhaust valve 213 that opens and closes in conjunction with opening and closing of the intake valve 211 is opened, an exhaust pipe 215 (exhaust port) is connected via an exhaust port (not shown) and an exhaust manifold 214. The exhaust manifold and the exhaust pipe 215 are all examples of the “exhaust passage” according to the present invention).

  On the other hand, on the upstream side of the intake port 210 in the intake pipe 207, a throttle valve 208 for adjusting the amount of intake air related to the intake air guided through a cleaner (not shown) is disposed. The throttle valve 208 is configured such that its drive state is controlled by a throttle valve motor 209 electrically connected to the ECU 100. The ECU 100 basically controls the throttle valve motor 209 so as to obtain a throttle opening corresponding to an accelerator opening detected by an unillustrated accelerator position sensor, but controls the operation of the throttle valve motor 209. It is also possible to adjust the throttle opening without intervening the driver's intention. That is, the throttle valve 209 is configured as a kind of electronically controlled throttle valve.

  An S / C (Start Converter) catalyst 216 is installed in the exhaust pipe 215. The S / C catalyst 216 is a so-called three-way catalyst capable of purifying CO (carbon monoxide), HC (hydrocarbon), and NOx (nitrogen oxide) exhausted from the engine 200, respectively. It is an example of the "catalyst device" concerning.

  On the upstream side of the S / C catalyst 216 in the exhaust pipe 215, an air-fuel ratio sensor 217, which is a so-called limiting current type oxygen concentration sensor, configured to detect the exhaust air-fuel ratio of the engine 200 is installed. . The air-fuel ratio sensor 217 is installed in a state where a part of its detection terminal is exposed to the exhaust pipe 215 so as to be exposed to the gas flowing through the exhaust pipe 215, and the air-fuel ratio of the exhaust gas flowing into the S / C catalyst 216 The exhaust air-fuel ratio can be detected by outputting a current corresponding to the output and outputting an output voltage corresponding to the output current from the sensor. The air-fuel ratio sensor 217 is electrically connected to the ECU 100, and the detected sensor output voltage corresponding to the air-fuel ratio is grasped by the ECU 100 at a constant or indefinite period.

On the downstream side of the S / C catalyst 216 in the exhaust pipe 215, an O ₂ sensor 218 capable of detecting the downstream oxygen concentration is installed. The O ₂ sensor 218 is a so-called electromotive force type oxygen concentration sensor, and is an example of the “detecting means” according to the present invention. The O ₂ sensor 218 is installed in a state where a part of the detection terminal is exposed to the exhaust pipe 215 so as to be exposed to the gas flowing through the exhaust pipe 215, and the oxygen concentration of the gas discharged from the S / C catalyst 216. A voltage corresponding to the sensor output voltage Vox can be output. More specifically, the O ₂ sensor 218 sets the reference voltage Voxst (for example, about 0.5 V) to the stoichiometric air-fuel ratio when the air-fuel ratio of the gas discharged from the S / C catalyst 216 is the stoichiometric air-fuel ratio. Is higher than the reference voltage when it is rich (assuming that the maximum voltage is Vmax (for example, about 0.9 V)), and is lower than the reference voltage when it is lean with respect to the theoretical air-fuel ratio (minimum) The voltage Vmin (for example, about 0.1 V) can be output as the sensor output voltage. The O ₂ sensor 218 is electrically connected to the ECU 100, and the detected sensor output voltage Vox corresponding to the oxygen concentration is grasped by the ECU 100 at a constant or indefinite period.

  In addition, a water jacket installed in a cylinder block that accommodates the cylinder 201 is provided with a water temperature sensor 219 for detecting a cooling water temperature related to cooling water (LLC) that is circulated and supplied to cool the engine 200. ing. The water temperature sensor 219 is electrically connected to the ECU 100, and the detected cooling water temperature Tw is referred to by the ECU 100 at a constant or indefinite period.

A U / F (Under Floor) catalyst configured as a three-way catalyst (however, the addition mode of the noble metal is different) is provided on the exhaust pipe 215 downstream of the O ₂ sensor 218 in the same manner as the S / C catalyst 216. Although it is installed, the illustration is omitted.

  Returning to FIG. 1, the IG key 300 is a start input means that is installed inside the vehicle 10 so that it can be operated by a driver. When a predetermined start operation (for example, an operation such as turning the IG key to a predetermined position) is performed on the IG key 300, the IG key 300 outputs an IG signal indicating that the engine 200 should be started. ing. Hereinafter, the output of the IG signal is appropriately expressed as “ignition on” or the like. On the contrary, the fact that the IG signal is not output is appropriately expressed as “ignition off” or the like.

  The starter 400 is a starting device for the engine 200, which is an example of the “scavenging means” according to the present invention. The starter 400 includes a flywheel that can rotate synchronously with the crankshaft of the engine 200, a pinion gear that meshes with the flywheel, a starter motor having a rotation shaft to which the pinion gear is fixed, and a drive device that drives the starter motor (whichever Is also a known starting device provided with a symbol omitted. This drive device is in a state of being electrically connected to the ECU 100, and the drive state is controlled by the ECU 100. Therefore, the rotation state of the starter motor is controlled by the ECU 100.

  Supplementally, when the starter motor rotates, the rotation is transmitted to the pinion gear, and is transmitted to the crankshaft 205 via the flywheel, whereby the engine 200 is physically driven and cranked. That is, the starter motor is a cranking motor that can perform cranking to start the engine 200 when the engine 200 is stopped.

  Further, supplementing the cranking, when the engine is started, the fuel is injected through the injector 212 and the fuel is ignited through the ignition device 202 during the cranking period in which the cranking is performed. 200 reaches the first explosion. After the first explosion, when the engine speed NE of the engine 200 reaches a predetermined value, a one-way clutch (also not shown) provided in the starter 400 to prevent power transmission in the reverse direction from the flywheel to the pinion gear. ), The starter motor idles, and the idling is detected (ie, detected as a change in load torque), whereby the starter motor is stopped and the cranking is finished.

  The battery 500 is configured to function as a power source for various electric drive devices and starters 400 in the engine 200, various electric auxiliary devices provided in the vehicle 10, or various electric drive type safety devices (ABS, VSC, etc.). This is an in-vehicle DC battery.

<Operation of Embodiment>
<Outline of air-fuel ratio F / B control>
In the vehicle 10, air-fuel ratio F / B control is employed for fuel injection control via the injector 212. In the air-fuel ratio F / B control, the oxygen concentration (output value is voltage) detected by the O ₂ sensor 218 downstream of the S / C catalyst 216 is referred to.

More specifically, first, based on the deviation between the sensor output voltage Vox of the O ₂ sensor 218 and the sensor output voltage Voxst corresponding to the target air-fuel ratio (that is, corresponding to the deviation between the target air-fuel ratio and the actual air-fuel ratio). Thus, proportional processing and integration processing (which may be performed by an algorithm according to known PI control) are performed, and a feedback correction value is calculated. Subsequently, the sensor output of the air-fuel ratio sensor 217 upstream of the S / C catalyst 216 (that is, the voltage corresponding to the air-fuel ratio) is corrected by this feedback correction value, so that the air-fuel ratio converges to the target air-fuel ratio. Therefore, the fuel injection amount is corrected.

On the other hand, when the engine 200 is placed in an engine stop state (so-called soak state) for a long time, for example, residual substances such as HC contained in the burned gas or unburned gas remaining in the exhaust pipe 215 are discharged from the O ₂ sensor 218 and the empty air. There may be cases where it adheres, adsorbs or adheres to the detection terminal of the fuel ratio sensor 217. As described above, in the state where the residual substance is adhered, adsorbed or fixed to the detection terminal, erroneous detection to the oxygen-deficient side (air-fuel ratio rich side) is likely to occur in each sensor, and the actual air-fuel ratio in air-fuel ratio F / B control Tends to shift to the lean side (that is, as a result of the feedback being made to reduce the fuel injection amount on the assumption that the air-fuel ratio is rich, the actual air-fuel ratio shifts to the lean side due to fuel shortage or excess air). For this reason, especially at the time of start-up that is significantly affected by this type of residual material, combustion becomes unstable and emission tends to deteriorate. Such deterioration of emission due to sensor rich deviation at the start is difficult to suppress even if the engine 200 is scavenged at the start. On the other hand, in the present embodiment, the deterioration of emissions at the time of start-up is efficiently and effectively suppressed by the scavenging control executed by the ECU 100.

  Here, with reference to FIG. 3, the detail of the scavenging control performed by ECU100 is demonstrated as operation | movement of this embodiment. FIG. 3 is a flowchart of the scavenging control.

  In FIG. 3, the ECU 100 determines whether or not the IG key 300 is in a state corresponding to the ignition off described above (step S101). When the IG key 300 is in a state corresponding to the ignition on (step S101: NO), the ECU 100 repeatedly executes step S101 and waits for processing, and when the IG key 300 is in a state along the ignition off ( Step S101: YES), the fuel supply via the injector 212 is stopped (Step S102).

  When the fuel supply is stopped, the engine 200 stops the self-sustaining rotation and enters the engine stop state. In this engine stop state, ECU 100 drives and controls starter 400 to start forced motoring of engine 200 (step S103). At this time, the rotation speed of the starter motor of the starter 400 is controlled so that the engine rotation speed NE of the engine 200 becomes a predetermined motoring rotation speed NE1 (for example, about several hundred rotations per minute). However, the value of the motoring rotational speed NE1 is not substantially limited as long as it does not exceed the operation limit of the starter 400.

  In this embodiment, “when the engine is stopped” according to the present invention refers to a period from when the fuel supply is stopped to when the engine 200 is restarted. May be started after the engine rotational speed NE becomes zero in the process of stopping the fuel supply, or may be started before it becomes zero. When forced motoring is started, the crankshaft 205 physically rotates with the rotation of the starter motor. Therefore, the piston 203 also physically rotates, and the intake valve 211 and the exhaust valve interlocked with the rotation of the crankshaft 205. By the opening / closing drive of 213, a flow of intake air from the intake pipe 207 to the exhaust pipe 215 through the combustion chamber is formed. This flow of intake air promotes purification of the exhaust pipe 215 and realizes scavenging.

When forced motoring is started, the ECU 100 determines whether or not the sensor output voltage Vox of the O ₂ sensor 218 corresponding to the oxygen concentration in the exhaust pipe 215 is equal to or lower than the voltage value Voxair corresponding to the oxygen concentration in the atmosphere. It discriminate | determines (step S104). Here, the voltage value Voxair corresponding to the oxygen concentration in the atmosphere is stored in the process of F / C control during deceleration.

  More specifically, in engine 200, fuel supply is stopped when the vehicle is in a predetermined deceleration condition (that is, F / C control is performed). The driving state of the engine 200 during the execution period of the F / C control is equivalent to forced motoring as long as it is limited to the operation of the intake / exhaust system (that is, whether the driving body that drives the crankshaft 205 is an inertial force, In the engine 200, a flow of intake air from the intake pipe 207 to the exhaust pipe 215 is formed.

Therefore, during the F / C period, the inside of the exhaust pipe 215 is gradually replaced with intake air (that is, the atmosphere), and the sensor output voltage Vox of the O ₂ sensor 218 gradually decreases. The minimum value of the sensor output voltage Vox in the process of the decrease is the voltage value Voxair corresponding to the oxygen concentration in the atmosphere. The ECU 100 stores this Voxair in the RAM in preparation for the coming scavenging control, and updates it whenever the F / C period comes. In the present embodiment, the voltage value Voxair corresponding to the oxygen concentration in the atmosphere is updated during the F / C period as described above. The value of Voxair is a preset fixed value or a plurality of fixed values. There may be.

When the sensor output voltage Vox is higher than the voltage value Voxair corresponding to the oxygen concentration in the atmosphere (step S104: NO), the ECU 100 continues forced motoring. On the other hand, when the sensor output voltage Vox is less than or equal to Voxair (step S104: YES), that is, when it is considered that the exhaust pipe 215 has been replaced with air at least at the installation location of the O ₂ sensor 218, the ECU 100 performs forced motoring. Stop (step S105).

Here, because of the structure of the O ₂ sensor 218, the detection terminal needs to be maintained in a predetermined active state when detecting the oxygen concentration. Therefore, the engine 200 is continuously warmed up by a predetermined sensor heater not only during the operation period of the engine 200 but also during the execution period of the forced motoring. Therefore, when the forced motoring is stopped in step S105 and the detection terminal does not need to be warmed up, the ECU 100 stops driving the sensor heater (step S106). When the driving of the sensor heater is stopped, the scavenging control ends.

  Next, the operation state of the engine 200 in the process of executing the scavenging control according to the present embodiment will be described visually with reference to FIG. FIG. 4 is a timing chart illustrating the transition of the operating state of the engine 200 during the scavenging control execution process.

  In FIG. 4, the IG signal, the sensor output voltage Vox, the engine rotational speed NE, and the time characteristics of the execution state of forced motoring are shown sequentially from the upper stage.

  When the IG signal is turned off, that is, the ignition is turned off at time T1, forced motoring is started, the oxygen concentration in the exhaust pipe 215 increases due to the inflow of intake air, and the sensor output voltage Vox starts to decrease. The sensor output voltage Vox continues to decrease during a period from time T1 to T2 when the engine rotation speed NE is maintained at the motoring rotation speed NE1. Here, at time T2 when the oxygen concentration in the exhaust pipe 215 becomes equal to or higher than the oxygen concentration in the atmosphere and the sensor output voltage Vox becomes equal to or lower than Voxair, the forced motoring is stopped, and the engine speed NE is zero after inertial driving. To fall.

Thus, according to the scavenging control according to the present embodiment, scavenging is performed by forced motoring after the engine 200 is stopped. At this time, whether or not scavenging is completed is determined based on the sensor output voltage Vox of the O ₂ sensor 218 installed in the exhaust pipe 215, and the sensor output voltage Vox is a voltage corresponding to the oxygen concentration in the atmosphere. When the value Voxair or less is reached, forced motoring ends (ie, scavenging) ends.

For this reason, at the end of scavenging by forced motoring, the amount of residual gas such as burned gas and unburned gas remaining around the detection terminal of the O ₂ sensor 218 is at least small enough to be practically treated as zero. Thus, during the soak period until the engine 200 is restarted, the possibility that various residual substances such as HC in the exhaust pipe adhere to, adsorb or adhere to the detection terminal of the O ₂ sensor 218 becomes substantially equal to zero.

Therefore, at the time of such restart, it is avoided that the sensor output voltage Vox of the O ₂ sensor 218 becomes higher (that is, shifts to the rich side) than the reference value (that is, the voltage value corresponding to the theoretical air-fuel ratio). The deterioration of the emission caused by the decrease in the air-fuel ratio convergence accuracy in the air-fuel ratio F / B control is suppressed.

Here, in particular, in the present embodiment, the state of the residual gas in the exhaust pipe at that time cannot always be accurately represented regardless of any adaptation made in advance such as the forced motoring time and the number of engine cycles during the forced motoring. (In other words, the state of the residual gas in the exhaust pipe can be changed in any way depending on the engine operation history, operation history, environmental conditions, etc.) Unlike the technical idea of determining the end of scavenging based on various judgment reference values, Based on the oxygen concentration around the O ₂ sensor 218 (that is, the state of the residual gas that can be changed variously depending on the operating condition or operating history of the engine 200 or the driving condition or operating history of the vehicle). Since the end of scavenging is determined (as a criterion), the start-up emission deterioration caused by insufficient scavenging is also conversely scavenging. The waste of energy resources (here, the power resources stored in the battery 500) due to the unnecessarily continuing for a long time is also avoided. That is, according to the scavenging control according to this embodiment, scavenging can be performed efficiently and effectively.

Note that the engine 200 is provided with an air-fuel ratio sensor 217 as a sensor that is concerned about a decrease in detection accuracy of a detection target due to residual gas, like the O ₂ sensor 218. However, the air-fuel ratio sensor 217 is disposed on the upstream side of the S / C catalyst 216, and when it is determined that the surroundings of the O ₂ sensor 218 on the downstream side of the S / C catalyst 216 are filled with air, It can be determined that the periphery of the fuel ratio sensor 217 is also filled with air. Considering the pressure loss in the S / C catalyst 216, the flow rate of the gas flowing into the air-fuel ratio sensor 217 upstream of the S / C catalyst 216 during scavenging is higher than the flow rate of the gas flowing into the O ₂ sensor 218. Therefore, the air-fuel ratio sensor 217 is in an environment where scavenging is more likely to proceed than the O ₂ sensor 218. Therefore, it is possible to suitably determine the end of scavenging based on the sensor output voltage Vox of the O ₂ sensor 218.

In FIG. 5, the branch position of the bypass pipe 610 is on the upstream side of the air-fuel ratio sensor 217, but from the viewpoint of efficient scavenging around the air-fuel ratio sensor 217, the bypass pipe 610 is It may branch from the exhaust pipe 215 in a section downstream of the air-fuel ratio sensor 217 and upstream of the S / C catalyst 216.
Second Embodiment
Next, the configuration of the engine 600 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic configuration diagram conceptually showing the configuration of the engine 600. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof is omitted as appropriate. The configuration of the vehicle according to the second embodiment is the same as that of the vehicle 10 according to the first embodiment except for the configuration of the engine.

In FIG. 5, one end portion of a bypass pipe 610 is connected to a branch portion set upstream of the S / C catalyst 216 in the exhaust pipe 215. The other end portion of the bypass pipe 610 is connected to a joining portion of the exhaust pipe 215 on the downstream side of the S / C catalyst 216 and the upstream side of the O ₂ sensor 218. That is, the bypass pipe 610 is an example of the “first communication path” according to the present invention that bypasses the S / C catalyst 216.

  The bypass pipe 610 is provided with a flow rate adjustment valve 620. The flow rate adjustment valve 620 includes a valve body whose communication area between the upstream section and the downstream space is variable according to the open / closed state and a drive device (for example, a solenoid) that drives the valve body. An electromagnetic on-off valve device as an example of the “first flow rate adjusting means” according to the present invention configured to be capable of continuously adjusting the gas amount of the bypass pipe 610, and a drive device that drives the valve body includes: The ECU 100 is controlled by an electrically connected ECU 100. That is, in the present embodiment, the ECU 100 also functions as an example of the “first flow rate control unit” according to the present invention.

  Here, scavenging control according to the present embodiment will be described with reference to FIG. FIG. 6 is a flowchart of the scavenging control according to this embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 3, and the description thereof will be omitted as appropriate.

  In FIG. 6, when forced motoring is started, the ECU 100 controls the flow rate via the drive device so that the valve body of the flow rate adjustment valve 620 is fully opened (that is, the state where the communication area is maximized). The adjustment valve 620 is driven and controlled (step S201). In addition, hereinafter, the fact that the valve body is fully open and fully closed is appropriately expressed as “the bypass valve is fully open and fully closed” or the like. When the flow rate adjustment valve 620 is fully opened, scavenging is continued until the sensor output voltage Vox becomes equivalent to the atmosphere as in the first embodiment, and when the sensor heater is stopped, the flow rate adjustment valve 620 is fully closed. Then, the scavenging control is finished (step S202).

  Next, the operation state of the engine 200 in the process of executing the scavenging control according to the present embodiment will be described visually with reference to FIG. FIG. 7 is a timing chart for explaining the transition of the operating state of the engine 200 in the execution process of the scavenging control. In the figure, the same reference numerals are given to the same parts as those in FIG. 4, and the description thereof will be omitted as appropriate.

  In FIG. 7, the time characteristics of the IG signal, sensor output voltage Vox, engine speed NE, flow rate adjustment valve 620 open / closed state and forced motoring execution state are shown in order from the top.

When the IG signal is turned off, that is, the ignition is turned off at time T3, forced motoring is started, the oxygen concentration in the exhaust pipe 215 increases due to the inflow of intake air, and the sensor output voltage Vox starts to decrease. At this time, since the flow rate adjustment valve 620 is fully opened, scavenging around the O ₂ sensor 218 is further promoted. As a result, the sensor output voltage Vox continues to decrease during a period from time T3 to T4 when the engine rotation speed NE is maintained at the motoring rotation speed NE1. Here, at time T4 when the oxygen concentration in the exhaust pipe 215 becomes equal to or higher than the oxygen concentration in the atmosphere and the sensor output voltage Vox becomes equal to or lower than Voxair, the forced motoring is stopped, and the engine speed NE is zeroed through inertial driving. To fall.

  Thus, according to the present embodiment, during the scavenging period by forced motoring, a part of the intake air used for scavenging is diverted at the branch portion of the exhaust pipe 215 and bypasses the S / C catalyst 216. Then, the air is guided to the merging portion of the exhaust pipe 215.

Therefore, a portion of the intake air, without being affected by the pressure loss due to the S / C catalysts 216, in other words, is guided around the O ₂ sensor 218 in a state in which reduced is suppressed in the flow rate, O ₂ near sensor Scavenging proceeds effectively. As a result, the scavenging period can be shortened, and more effective use of power resources can be achieved. It should be noted that since the determination of the end of the scavenging is made based on the oxygen concentration around the O ₂ sensor when the flow rate of the gas supplied to the scavenging of the O ₂ sensor 218 changes in this way, it is efficient and effective. The same advantage as in the first embodiment that the scavenging can be realized is guaranteed without any change.

  In this embodiment, the open / close state of the flow rate adjustment valve 620 is controlled in a binary manner between the fully open state and the fully closed state, but the open / close state of the bypass valve 620 is variable stepwise or continuously. The gas flow rate of the bypass pipe 610 may be controlled more precisely. For example, in this case, the open / close state may be appropriately determined in view of the progress of scavenging around the air-fuel ratio sensor 217.

<Third Embodiment>
Next, a configuration of an engine 700 according to the third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a schematic configuration diagram conceptually showing the configuration of the engine 700. As shown in FIG. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof is omitted as appropriate. The configuration of the vehicle according to the third embodiment is the same as that of the vehicle 10 according to the first embodiment except for the configuration of the engine.

In FIG. 8, one end portion of a bypass pipe 710 is connected to a branch portion set on the upstream side of the throttle valve 208 in the intake pipe 207. The other end portion of the bypass pipe 710 is connected to a joining portion of the exhaust pipe 215 on the downstream side of the S / C catalyst 216 and the upstream side of the O ₂ sensor 218. That is, the bypass pipe 710 is an example of the “second communication path” according to the present invention that bypasses the combustion chamber and the S / C catalyst 216.

  The bypass pipe 710 is provided with a flow rate adjustment valve 720. The flow rate adjusting valve 720 includes a valve body that changes the communication area between the upstream section and the downstream space according to the open / closed state and a drive device (for example, a solenoid) that drives the valve body. An electromagnetic on-off valve device as an example of the “second flow rate adjusting means” according to the present invention configured to continuously adjust the gas amount of the bypass pipe 710, and a driving device that drives the valve body includes: The ECU 100 is controlled by an electrically connected ECU 100. That is, in the present embodiment, the ECU 100 also functions as an example of the “second flow rate control unit” according to the present invention.

In such a configuration, as in the second embodiment, the valve body of the flow rate adjustment valve 720 is in a fully open state (that is, a state in which the above-described communication area is maximized) during the execution of scavenging by forced motoring. When the flow control valve 720 is driven and controlled via the drive device, a part of the intake air used for scavenging is bypassed from the intake pipe 207 to the combustion chamber and the S / C catalyst 216 in the exhaust pipe 215. Guided to the merging position. For this reason, a part of the intake air is guided to the vicinity of the O ₂ sensor 218 without being affected by the pressure loss by the S / C catalyst 216 and without being contaminated by the residual gas remaining in the combustion chamber. Scavenging around the _two sensors proceeds effectively. As a result, the scavenging period can be shortened, and more effective use of power resources can be achieved.

  In FIG. 8, the bypass pipe 710 is branched from the upstream side of the throttle valve 208 in the intake pipe 207, but the bypass pipe 710 is branched from the downstream side of the throttle valve 208, for example, an intake manifold (not shown). You may do it.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and vehicle scavenging control with such a change is possible. The apparatus is also included in the technical scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram conceptually showing a configuration of a part related to a vehicle scavenging control apparatus according to the present invention in a vehicle according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram conceptually showing a configuration of an engine in the vehicle of FIG. 1. It is a flowchart of the scavenging control performed by ECU. It is a timing chart explaining transition of the operating state of an engine in the execution process of scavenging control. It is a schematic block diagram which represents notionally the structure of the engine which concerns on 2nd Embodiment of this invention. It is a flowchart of the scavenging control which concerns on 2nd Embodiment. FIG. 10 is a timing chart for explaining the transition of the operating state of the engine in the execution process of the scavenging control according to the second embodiment. It is a schematic block diagram which represents notionally the structure of the engine which concerns on 3rd Embodiment of this invention.

Explanation of symbols

10 ... vehicle, 100 ... ECU, 200 ... engine, 201 ... cylinder, 203 ... piston 205 ... Crankshaft, 216 ... S / C catalyst, 217 ... air-fuel ratio sensor, 218 ... _{O 2} sensor, 300 ... IG key 400 ... starter, 500 ... battery.

Claims (5)

A scavenging control device in a vehicle comprising an internal combustion engine having a detecting means capable of detecting an oxygen concentration in an exhaust passage, and a scavenging means capable of scavenging the exhaust passage,
Scavenging control means for controlling the scavenging means so that the scavenging is started when the internal combustion engine is stopped;
Determining means for determining whether or not the scavenging is completed based on the detected oxygen concentration;
The scavenging control means controls the scavenging means so that the scavenging is completed when it is determined that the scavenging is completed. 2. The scavenging control device for a vehicle according to claim 1, wherein the determination unit determines that the scavenging is completed when the detected oxygen concentration corresponds to an oxygen concentration in the atmosphere. The scavenging control device for a vehicle according to claim 1 or 2, wherein the internal combustion engine includes a catalyst device capable of purifying exhaust gas upstream of the detection means in the exhaust passage. The internal combustion engine has a section corresponding to the upstream side of the catalyst device in the exhaust passage and a section corresponding to the downstream side of the catalyst device and the upstream side of the detection means in the exhaust passage through the catalyst device. A first communication path that communicates with the first communication path, and a first flow rate adjusting unit that is installed in the first communication path and that can adjust the flow rate of the gas in the first communication path,
The vehicle scavenging control device comprises:
The apparatus further comprises first flow rate control means for controlling the first flow rate adjustment means so that the gas is guided to the first communication path during the scavenging period in which the scavenging is performed. A scavenging control device for a vehicle according to claim 1. The internal combustion engine includes a second communication passage that communicates an intake passage and a section corresponding to the downstream side of the catalyst device and the upstream side of the detection means in the exhaust passage without passing through a combustion chamber, A second flow rate adjusting means installed in the communication path and capable of adjusting a gas flow rate in the second communication path;
The vehicle scavenging control device comprises:
The apparatus further comprises second flow rate control means for controlling the second flow rate adjustment means so that the gas is guided to the second communication path during the scavenging period in which the scavenging is performed. A scavenging control device for a vehicle according to claim 1.

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