JP3783431B2 - Failure diagnosis device for hybrid vehicles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a failure diagnostic device for a hybrid vehicle, which can accurately and easily judge the diagnosis of the failure of an evaporated fuel recovering system and an exhaust gas purifying catalyst while improving performance of fuel consumption. SOLUTION: In a hybrid vehicle, an evaporated fuel recovering system is arranged which is equipped with a fuel tank 31 and a purge passage 37 communicating the fuel tank 31 with a surge tank 25, negative pressure in the inside of the surge tank 25 is introduced to the evaporated fuel recovering system, and the failure of the evaporated fuel recovering system is diagnosed based on pressure change caused by the introduction of the negative pressure. The deterioration of a three-way catalyst is judged based on a reverse ratio A/B being a ratio of rich reverse frequency A to lean reverse frequency B of upstream and downstream side O2 sensors 28, 29. An engine 1 is basically operated at high efficiency, therefore performance of fuel consumption can be improved, and also the failure of the evaporative fuel recovering system and exhaust gas purifying catalyst can be accurately and easily diagnosed.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a failure diagnosis apparatus for a hybrid vehicle.
[0002]
[Prior art]
In general, in an automobile equipped with an engine (for example, a gasoline engine), part of the fuel in the fuel tank evaporates to become fuel vapor (evaporated fuel). When this fuel vapor is discharged into the atmosphere as it is, Contamination and loss of fuel resources. Therefore, normally, an automobile is provided with an evaporative fuel recovery system in order to recover (introduce) fuel vapor generated in the fuel tank into the intake passage and use it as fuel.
[0003]
In such an evaporative fuel recovery system, a purge passage (evaporative fuel recovery passage) that normally connects the upper space in the fuel tank and the intake passage is provided, and a canister that adsorbs fuel vapor is interposed in the purge passage. Has been. The canister is provided with an air release passage whose tip is open to the atmosphere. A purge valve that opens and closes the purge passage is interposed in the purge passage closer to the intake passage than the canister. Thus, the fuel vapor generated in the fuel tank is first adsorbed by the canister, and the fuel vapor adsorbed by the canister passes through the purge passage by the air introduced from the atmosphere release passage to the canister when the purge valve is opened. Through the intake passage.
[0004]
However, in such an evaporative fuel recovery system, abnormalities or failures such as malfunction of the purge valve or breakage of the purge passage may occur. Therefore, a failure diagnosis device for diagnosing the presence or absence of such an abnormality or failure is generally provided in the evaporated fuel recovery system. As such a failure diagnosis device, there are widely used devices that introduce intake negative pressure in the intake passage into the evaporated fuel recovery system and determine whether there is an abnormality or failure in the evaporated fuel recovery system based on the pressure change. (For example, refer to Japanese Patent Laid-Open No. 5-256214).
[0005]
In general, in an engine, air pollutants such as HC (hydrocarbon), CO (carbon monoxide), and NOx (nitrogen oxide) are purified by an exhaust gas purification catalyst such as a three-way catalyst. However, the exhaust gas purification catalyst may be deteriorated due to high temperature, poisoning due to catalyst poisoning, or the like, and the catalytic activity may be lowered. Therefore, in recent years, failure diagnosis devices that determine (diagnose) the presence or absence of deterioration of an exhaust gas purification catalyst, for example, upstream and downstream of a catalytic converter, respectively. ₂ A sensor (oxygen sensor) is provided. ₂ 2. Description of the Related Art A failure diagnosis device is used that determines the presence or absence of deterioration of an exhaust gas purification catalyst based on an inversion ratio obtained from a detection value of a sensor. Here, “reversal ratio” means upstream O within a certain time. ₂ Sensor rich / lean reversal count A and downstream O ₂ This is a numerical value defined by the ratio A / B with the number of inversions B of the rich / lean sensor.
[0006]
[Problems to be solved by the invention]
By the way, in recent years, from the viewpoint of prevention of global warming, etc. ₂ There is a need to reduce emissions. Therefore, a hybrid vehicle that uses an engine (for example, a gasoline engine) and an electric motor as a power source to improve fuel efficiency attracts attention. In such a hybrid vehicle, the engine operates in a relatively high efficiency state, so that the fuel efficiency is greatly improved, and as a result, the CO ₂ Emissions are greatly reduced.
[0007]
In such a hybrid vehicle, an evaporative fuel recovery system and its failure diagnosis device are usually provided in the same manner as an ordinary gasoline engine vehicle in order to prevent the fuel vapor from being released into the atmosphere. However, in a hybrid vehicle, the engine is often stopped and the vehicle is driven only by an electric motor. Therefore, when a failure diagnosis is performed by introducing intake negative pressure into an evaporative fuel recovery system, the time or period when the failure diagnosis should be performed There is a problem that it is difficult to set the timing. Further, in the hybrid vehicle, since the engine is operated at a relatively high efficiency as described above, the intake negative pressure is hardly generated, so that there is a problem that the failure diagnosis of the evaporated fuel recovery system becomes more difficult.
[0008]
In addition, an exhaust gas purification catalyst is also provided in a hybrid vehicle. In this case, the engine is mostly operated in a low rotation / high load region, and therefore, an operating state suitable for determining the deterioration of the exhaust gas purification catalyst due to the inversion ratio. That is, there is a problem that the amount of exhaust gas is very low and failure diagnosis cannot be performed easily.
[0009]
The present invention has been made to solve the above-described conventional problems, and is a hybrid vehicle capable of accurately and easily diagnosing a failure or abnormality of an evaporative fuel recovery system and further deterioration of an exhaust gas purification catalyst. Providing a failure diagnosis apparatus is a problem to be solved.
[0010]
[Means for Solving the Problems]
The failure diagnosis apparatus for a hybrid vehicle according to the first aspect of the present invention, which has been made to solve the above problems, includes (a) an engine (for example, a gasoline engine) that can drive a drive wheel, and an electric type A failure diagnosis device for a hybrid vehicle provided with a drive motor and configured to travel while changing the drive mode (drive source) of the drive wheels according to the vehicle operation state (including the battery charge state), (B) an evaporative fuel recovery system comprising a fuel tank, and an evaporative fuel recovery passage (purge passage) communicating the fuel tank and the engine intake passage; (c) evaporative fuel recovery of the negative pressure in the intake passage; An abnormality determination means for introducing an abnormality in the evaporated fuel recovery system (fault diagnosis) based on a pressure change in the evaporated fuel recovery system due to the introduction of the negative pressure; and (d) after starting the vehicle operation. Engine is Less fuel evaporation in the fuel tank Appropriate for determining the abnormality of the engine so that the abnormality determination means can execute the abnormality determination of the evaporated fuel recovery system during the initial engine operation (so that negative pressure can be introduced into the evaporated fuel recovery system) Large intake negative pressure An abnormality determination control means for operating in a predetermined abnormality determination operation state is provided.
[0011]
According to this hybrid vehicle failure diagnosis apparatus, high-load operation is basically performed from the viewpoint of improving fuel efficiency, and even in a hybrid vehicle in which an operation state suitable for failure diagnosis of the evaporated fuel recovery system is difficult to obtain, Since the operation duration is relatively short and the temperature of the fuel in the fuel tank is not high, the failure diagnosis is performed in an operating state suitable for failure diagnosis of the evaporated fuel recovery system with a small amount of fuel evaporation and a large intake negative pressure. It can be performed. Therefore, it is possible to accurately and easily determine the failure or abnormality of the evaporated fuel recovery system while improving the fuel efficiency.
[0012]
In the hybrid vehicle failure diagnosis apparatus, the abnormality determination operation state includes, for example, a state where the engine is operated in a middle rotation / medium load region (region where intake negative pressure is large and the engine is stable). Further, the amount of fuel supplied to the engine is feedback-controlled (O ₂ When air-fuel ratio control means for feedback control is provided, the abnormality determination operation state includes a state in which feedback control by the air-fuel ratio control means can be executed. In this case, the failure diagnosis of the evaporated fuel recovery system can be more accurately executed while suppressing the fluctuation of the actual air-fuel ratio due to the purge even under operating conditions with many restrictions such as a hybrid vehicle.
[0013]
In the above hybrid vehicle failure diagnosis apparatus, it is preferable that the engine is operated when the vehicle is operating at a high load (for example, during rapid acceleration or high speed driving) or when the battery charge is reduced. It is sometimes more preferable that the engine is controlled so as to have high efficiency (for example, low rotation and high load). In this way, the failure diagnosis of the evaporative fuel recovery system is surely performed despite the fact that the engine is a hybrid vehicle with few opportunities for operation.
[0014]
In the hybrid vehicle failure diagnosis apparatus, it is preferable that the abnormality determination operation state that increases the intake negative pressure is maintained (prioritized) when the vehicle high load operation is detected when the engine is in the abnormality determination operation state. . In this way, sufficient engine output can be secured, and the failure diagnosis of the evaporated fuel recovery system can be reliably performed despite the fact that there are few negative pressure generation modes.
[0015]
In the hybrid vehicle failure diagnosis apparatus, the abnormality determination control means performs the abnormality determination by forcibly starting the engine operation within a predetermined period (for example, while the fuel evaporation amount is small) after the vehicle operation is started. It is preferable that The predetermined period is preferably set according to the outside air temperature, the vehicle speed, and the like. In this way, failure diagnosis of the evaporated fuel recovery system can be performed when the fuel evaporation amount is small, and the accuracy of the failure diagnosis is improved.
[0016]
In the hybrid vehicle failure diagnosis apparatus, the abnormality determination control means causes the engine to start high-efficiency operation when vehicle high-load operation is detected during vehicle operation, while the engine even when vehicle high-load operation ends. It is preferable that the engine is continuously operated until the temperature reaches the predetermined reference temperature to perform abnormality determination. In this way, the failure diagnosis of the evaporated fuel recovery system can be performed using the warm-up operation of the engine.
[0017]
In the hybrid vehicle failure diagnosis apparatus, when the exhaust gas purification catalyst for purifying the exhaust gas of the engine and the catalyst deterioration determination means for determining the deterioration of the exhaust gas purification catalyst are provided, the catalyst deterioration determination means The engine continues to operate even after the introduction of the negative pressure to the evaporated fuel recovery system by the abnormality determination control means is completed, and the deterioration determination is performed after the temperature of the exhaust gas purification catalyst exceeds a predetermined temperature. It is preferable. In this way, the deterioration diagnosis of the exhaust gas purification catalyst can be accurately and easily performed using the failure diagnosis of the evaporated fuel recovery system.
[0018]
In the hybrid vehicle failure diagnosis apparatus, an engine motor and a battery that can convert engine output into electric power are provided, and when the engine motor is determined to be abnormal by the abnormality determination control means, the engine output It is preferable that the battery is charged by converting the power into power. In this way, charging of the battery is promoted.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described. First, a schematic configuration of a hybrid vehicle including a failure diagnosis apparatus according to the present invention will be described.
As shown in FIG. 1, the hybrid vehicle W is provided with an engine 1 and a drive motor 2 as power sources. Here, the engine 1 generates driving force (torque) using gasoline as fuel. The drive motor 2 generates driving force (torque) using electric power supplied from the battery 3 as an energy source. Here, the battery 3 is appropriately charged by the engine motor 4 that is rotationally driven by the engine 1. The engine motor 4 is energized from the battery 3 when the engine 1 is started to start (crank) the engine 1.
[0021]
Here, the drive motor 2 and the engine motor 4 are both DC motors that rotate and output torque when energized, and that generate electric power when they are mechanically driven to rotate, and therefore they are essentially the same. It has the function of However, the drive motor 2 is mainly used for outputting the drive torque of the hybrid vehicle W by energization from the battery 3, and is also used for charging the battery 3 by generating power (regeneration) during deceleration. On the other hand, the other engine motor 4 is mainly used to rotate and drive the engine 1 to generate electric power and charge the battery 3, while the secondary engine motor 4 is also used to output engine driving torque when energized from the battery 3. Not too much.
[0022]
In this hybrid vehicle W, the driving force of the engine 1 is, in order, the torque converter 5 (T / C), the clutch 6, the automatic transmission 7 (A / T), and the differential mechanism 8 (differential device). ) To the left and right drive wheels 9 and 10. The driving force is transmitted from the automatic transmission 7 to the differential mechanism 8 through a part of the gear train 11.
[0023]
On the other hand, the driving force of the drive motor 2 is transmitted to the drive wheels 9 and 10 via the gear train 11 and the differential mechanism 8. Here, as will be described later, the battery 3 is charged by the engine motor 4 or the drive motor 2 (at the time of regeneration), while being discharged to the drive motor 2 (in some cases, the engine motor 4). However, the power control (including switching between charging and discharging) is performed by a power controller 15 controlled by a system controller 14 (computer).
[0024]
Here, the exhaust gas of the engine 1 is discharged into the atmosphere via the exhaust passage 12. A catalytic converter 13 using a three-way catalyst is interposed in the exhaust passage 12 to purify air pollutants (for example, HC, CO, NOx, etc.) in the exhaust gas.
The system controller 14 performs various controls of the hybrid vehicle W. The system controller 14 includes a depression amount α (accelerator opening α) of the accelerator pedal 16 and whether or not the brake pedal 17 is depressed. , Vehicle speed V, engine water temperature Tw, battery charge state or battery voltage, intake air amount Qa, engine speed Ne, throttle opening Tv, O in exhaust gas ₂ Various control information such as concentration (actual air-fuel ratio) is input.
[0025]
Next, a specific configuration of the engine 1 or its accessory device will be described.
As shown in FIG. 2, an intake passage 20 (intake system) is provided to supply air for fuel combustion to the engine 1, and a common intake passage 21 is provided in the intake passage 20 to take in air from the atmosphere. Is provided. The common intake passage 21 includes an air cleaner 22 for removing dust and the like in the intake air in order from the upstream side in the flow direction (leftward in FIG. 2) of the intake air (air introduced into the intake passage 20). An air flow sensor 23 for detecting the intake air amount and a throttle valve 24 for restricting the intake air are provided. The downstream end of the common intake passage 21 is connected to a surge tank 25 (volume part) that stabilizes the flow of intake air.
[0026]
The surge tank 25 is connected to a plurality of (only one is shown) independent intake passages 26 for supplying intake air to each cylinder (not shown) of the engine 1, and each independent intake passage 26 is connected to intake air. A fuel injection valve 27 for injecting (supplying) fuel is provided therein. An exhaust passage 12 for exhausting the exhaust gas of the engine 1 has an upstream side O disposed at a slightly upstream side of the catalytic converter 13. ₂ The downstream side O which is arranged slightly downstream of the sensor 28 (oxygen sensor) and the catalytic converter 13 ₂ A sensor 29 (oxygen sensor) is provided.
[0027]
Upstream O ₂ Sensor 28 and downstream O ₂ Each sensor 29 has a large output (voltage) depending on whether the actual air-fuel ratio (actual air-fuel ratio) is richer or leaner than the theoretical air-fuel ratio (A / F = 14.7, λ = 1). For example, in an output range of 0 to 1 V, a threshold voltage VB (approximately 0 _. 4V), the output voltage changes greatly. A higher output voltage is richer and a lower output voltage is leaner.
[0028]
Where upstream O ₂ The sensor 28 mainly feedback-controls the fuel injection amount from the fuel injection valve 27 so that the actual air-fuel ratio becomes the stoichiometric air-fuel ratio (O ₂ Feedback control). Both O ₂ The sensors 28 and 29 are used for determining the deterioration of the three-way catalyst (exhaust gas purification catalyst) based on the inversion ratio, as will be described in detail later. Each O ₂ Each of the sensors 28 and 29 incorporates an electric heater for ensuring an activation temperature.
[0029]
Hereinafter, the configuration of a fuel supply system for supplying fuel (gasoline) to the fuel injection valve 27 of the engine 1 will be described. The fuel supply system is provided with a fuel tank 31 for storing fuel, and the fuel in the fuel tank 31 is supplied to the fuel injection valve 27 by the fuel pump 32 via the fuel supply passage 33. ing. Excess fuel that has not been injected by the fuel injection valve 27 is returned to the fuel tank 31 via the fuel recirculation passage 34. The fuel supply passage 33 is provided with a fuel filter 35 for removing foreign matters in the fuel, and the fuel recirculation passage 34 is provided with a pressure regulator 36 for adjusting the fuel supply pressure in accordance with the intake pressure. ing.
[0030]
Hereinafter, an evaporative fuel recovery system (evaporated fuel supply path) for recovering (introducing) fuel vapor (evaporated fuel) generated in the fuel tank 31 into the intake passage 20 and using it as fuel will be described. This evaporative fuel recovery system (including the fuel tank 31) is provided with a purge passage 37 (evaporated fuel recovery passage) that communicates the upper space of the fuel tank 31 and the surge tank 25 (intake passage 20). A canister 38 that adsorbs fuel vapor is interposed in the passage 37. Here, as viewed in the flow direction of the fuel vapor (generally rightward in FIG. 2), the purge passage 37 upstream of the canister 38 (hereinafter referred to as “upstream purge passage 37”) is provided in the fuel tank 31. A pressure sensor 39 for detecting pressure (hereinafter referred to as “tank internal pressure”) and a control valve 40 (PCTV valve) for opening and closing the upstream purge passage 37 are provided. A rollover valve 41 is provided in the fuel tank 31 in the vicinity of the upstream end of the upstream purge passage 37 to prevent the liquid fuel from flowing into the upstream purge passage 37 when it falls. On the other hand, a purge valve 43 (purge valve) for opening and closing the downstream purge passage 37 is provided in the purge passage 37 downstream of the canister 38 (hereinafter referred to as “downstream purge passage 37”).
[0031]
The canister 38 is provided with an air release passage 44 whose tip is open to the atmosphere. The air release passage 44 is introduced into the canister 38 via the air release passage 44 and the air release valve 45 (CDCV valve) for opening and closing the air release passage 44 in order from the canister side to the tip side. And an air filter 46 for removing dust contained in the air.
[0032]
By the way, as described above, the hybrid vehicle W is provided with the engine 1 and the drive motor 2 as drive sources, and these drive modes (operation modes) are preferably changed according to the operating state of the hybrid vehicle W. Hereinafter, a specific drive mode in the hybrid vehicle W will be described with reference to FIGS. 3 to 8 as appropriate. Note that the drive modes described below are merely examples, and the present invention is of course not limited to such drive modes.
[0033]
(1) When starting
As shown in FIG. 3, in principle, when starting, the clutch 6 is released and the engine 1 is stopped, while electric power is supplied from the battery 3 to the drive motor 2, and the drive motor 2 is powered. At this time, the drive wheels 9 and 10 are driven only by the drive motor 2. The engine motor 4 does not operate (stops) because the engine 1 is stopped and no power is supplied from the battery 3.
[0034]
However, as shown in FIG. 4, at the time of sudden start, electric power is supplied from the battery 3 to the drive motor 2 and the drive motor 2 is powered, and the clutch 6 is engaged and the engine 1 is started to perform high output operation. . Further, electric power is supplied from the battery 3 to the engine motor 4, and the engine motor 4 also powers. Thus, the drive wheels 9 and 10 are strongly driven by the engine 1, the drive motor 2, and the engine motor 4.
[0035]
(2) When the engine starts
As shown in FIG. 5, when the engine is started, the clutch 6 is released, power is supplied from the battery 3 to the engine motor 4, and the engine motor 4 is powered. At this time, the engine 1 is started (cranked) by the engine motor 4. The drive motor 2 is stopped (however, it is not stopped when the engine 1 is started during traveling).
[0036]
(3) During deceleration
As shown in FIG. 6, at the time of deceleration, the engine 1 stops and the clutch 6 is released. At this time, the drive motor 2 is reversely driven by the drive wheels 9 and 10, and the drive force of the drive wheels 9 and 10 is regenerated to the drive motor 2. Thus, the drive motor 2 generates electric power, and the battery 3 is charged with this electric power.
[0037]
(4) During sudden acceleration
At the time of rapid acceleration, as shown in FIG. 4, electric power is supplied from the battery 3 to the drive motor 2, and the drive motor 2 is powered, and the engine 1 performs a high output operation. At this time, electric power is also supplied from the battery 3 to the engine motor 4, and the engine motor 4 also powers. Thus, the drive wheels 9 and 10 are strongly driven by the engine 1, the drive motor 2, and the engine motor 4.
[0038]
(5) During steady running
During steady running at a low load, as shown in FIG. 3, in principle, the clutch 6 is released and the engine 1 is stopped, while power is supplied from the battery 3 to the drive motor 2, and the drive motor 2. Powers. At this time, the drive wheels 9 and 10 are driven only by the drive motor 2. Note that the engine motor 4 does not act at all.
However, when the engine is cold or when the battery charge is low, the clutch 6 is engaged and the engine 1 is operated. At this time, the engine motor 4 is rotationally driven by the engine 1 to generate electric power, and the battery 3 is charged by this electric power. .
[0039]
As shown in FIG. 7, during steady running at a medium load, the engine 1 performs high-efficiency operation, and no power is supplied from the battery 3 to the drive motor 2. At this time, the drive wheels 9 and 10 are driven only by the engine 1, and the drive motor 2 is in a non-output state. The engine motor 4 is rotationally driven by the engine 1 to generate electric power, and the battery 3 is charged by this electric power.
[0040]
At the time of steady running under a high load, as shown in FIG. 4 described above, electric power is supplied from the battery 3 to the drive motor 2 and the drive motor 2 is powered, and the engine 1 performs a high output operation. At this time, electric power is also supplied from the battery 3 to the engine motor 4, and the engine motor 4 also powers (however, it may generate electricity depending on the operating state). Thus, the drive wheels 9 and 10 are strongly driven by the engine 1, the drive motor 2, and the engine motor 4.
[0041]
(6) When stopped
When the vehicle stops, in principle, the clutch 6 is released, the engine 1 stops, and the drive motor 2 also stops (no power is supplied from the battery 3 to the drive motor 2). The engine motor 4 does not operate (stops) because the engine 1 is stopped and no power is supplied from the battery 3.
However, as shown in FIG. 8, when the engine is cold or when the battery charge is low, the engine 1 is operated, and at this time, the engine motor 4 is rotationally driven by the engine 1 to generate electric power, and the battery 3 is charged by this electric power. The
[0042]
As described above, the engine 1 is provided with an evaporative fuel recovery system for recovering the fuel vapor generated in the fuel tank 31 to the intake passage 20. Hereinafter, a procedure for recovering the fuel vapor in this evaporative fuel recovery system is provided. An example will be described.
In this evaporative fuel recovery system, the control valve 40 and the air release valve 45 are normally opened while the purge valve 43 is closed. At this time, the upper space portion of the fuel tank 31 (hereinafter referred to as “tank space portion”) basically communicates with the atmosphere via the upstream purge passage 37, the canister 38, and the air release passage 44. . Thus, when the internal pressure of the tank increases due to evaporation (vaporization) of the fuel in the fuel tank 31, the air including the fuel vapor in the tank space is sequentially released from the upstream purge passage 37, the canister 38, and the atmosphere. It is discharged into the atmosphere via the passage 44. At that time, since the fuel vapor is adsorbed (collected) by the canister 38, only air is eventually released into the atmosphere.
[0043]
Then, when an appropriate amount (for example, about 70% of the saturated adsorption amount) of fuel vapor is adsorbed to the canister 38 or is estimated to be adsorbed, and the engine 1 is operating (the fuel cut operation is performed). The control valve 40 is closed, while the purge valve 43 and the air release valve 45 are opened. At this time, the surge tank 25 communicates with the atmosphere via the downstream purge passage 37, the canister 38, and the atmosphere release passage 44. Thus, due to the negative pressure in the surge tank 25, air in the atmosphere is sequentially sucked into the surge tank 25 via the atmosphere release passage 44, the canister 38, and the downstream purge passage 37. At this time, the fuel vapor adsorbed on the canister 38 is released from the canister 38 and purged to the surge tank 25. The fuel vapor purged in the surge tank 25 is then utilized (burns) as fuel in the engine 1.
[0044]
By the way, in this evaporated fuel recovery system, sometimes malfunctions or abnormalities such as malfunction of various valves 40, 43, 45, damage to the purge passage 37, etc. may occur. Therefore, in this hybrid vehicle W, failure diagnosis is appropriately performed in order to determine (diagnose) a failure or abnormality of the evaporated fuel recovery system. Hereinafter, this failure diagnosis method will be specifically described.
[0045]
First, the basic concept of failure diagnosis of this evaporated fuel recovery system will be described. In this failure diagnosis, basically, a negative pressure in the intake passage 20 (surge tank 25) is introduced into the evaporative fuel recovery system, and evaporation is performed based on a pressure change in the evaporative fuel recovery system due to the introduction of the negative pressure. A failure or abnormality of the fuel recovery system is determined. Hereinafter, a more specific failure diagnosis method will be described.
As shown in FIG. 9, this failure diagnosis is performed when the purge valve 43 and the atmosphere release valve 45 are opened while the control valve 40 is closed and the fuel vapor is purged. That is, first, during the purge, an appropriate time t ₁ Then, while closing the atmosphere release valve 45, the control valve 40 is opened and the failure diagnosis is started. The purge valve 43 is left open.
[0046]
Thereby, the negative pressure in the surge tank 25 is introduced into the evaporated fuel recovery system, and the tank internal pressure gradually decreases (the negative pressure increases). Then, the tank internal pressure decreases to a predetermined reference pressure (for example, −200 mmAq gauge (water column)) (time t ₂ ) Further, when the tank internal pressure slightly decreases t _Three To close the purge valve 43. As a result, the fuel vapor recovery system closer to the fuel tank than the purge valve 43 is shut off from the atmosphere and sealed. Thereafter, the tank internal pressure detected by the pressure sensor 39 slightly increases (returns) due to a delay in the propagation of the negative pressure into the tank space.
[0047]
Here, the time t when the increase in the tank internal pressure is almost finished _Four Is stored as a first tank internal pressure value TP1. And the time t which detected the 1st tank internal pressure value TP1 _Four T when a predetermined measurement time (for example, 30 seconds) has elapsed since _Five Is stored as the second tank internal pressure value TP2. At this time t _Five Then, the control valve 40 is closed, and then the atmosphere release valve 45 is opened. The purge valve 43 is kept closed. After this time t ₆ Then, the purge valve 43 is opened, and the purge of the fuel vapor adsorbed on the canister 38 is resumed.
[0048]
In such a process, first, the time required for the tank internal pressure to substantially drop to the reference pressure (for example, −200 mmAq gauge) after the start of failure diagnosis, that is, the time point t. ₁ To time t _Four Elapsed time until (t _Four -T ₁ ), It is determined whether or not there is a serious leak failure (large leak) due to poor connection of the purge passage 37, open adhesion of the air release valve 45 (no opening), or the like. That is, time (t _Four -T ₁ ) Is longer than a preset reference time (for example, 30 seconds), it is determined that there is a large leak. In addition, time t ₁ Thereafter, when the tank internal pressure does not drop to the reference pressure, it is determined that there is a large leak. The time (t _Four -T ₁ ), (T _Three -T ₁ ) Or (t ₂ -T ₁ ).
[0049]
Next, a differential pressure (TP2−TP1) between the second tank internal pressure value TP2 and the first tank internal pressure value TP1, that is, a time point t. _Four To time t _Five On the basis of the degree of increase in the tank internal pressure during the period up to (measurement time), it is determined whether or not there is a minor leak failure (small leak) due to minor damage or the like of the purge passage 37. That is, when the differential pressure (TP2-TP1) is larger than a preset threshold value, for example, when the second tank internal pressure value TP2 is higher than SP2, the negative pressure in the purge passage 37 is properly maintained. It is determined that there is a small leak that cannot be performed.
Note that time t _Five To time t ₆ When the degree of increase in the tank internal pressure is greater than a predetermined reference value during the period up to this time, it is determined that the control valve 40 is stuck open (open).
[0050]
By the way, as described above, the three-way catalyst (exhaust gas purification catalyst) in the catalytic converter 13 may deteriorate due to high temperature (thermal deterioration), poisoning due to catalyst poisoning, and the like, and the catalytic activity may decrease. Therefore, in this hybrid vehicle W, deterioration diagnosis (that is, failure diagnosis) for determining the presence or degree of deterioration of the three-way catalyst is performed, and a diagnosis method for this deterioration diagnosis will be described below.
[0051]
In the deterioration diagnosis of the three-way catalyst, when the engine 1 is in a predetermined operation state suitable for the deterioration diagnosis, for example, the engine 1 is operated so as to have a medium exhaust gas amount (medium exhaust gas amount) (that is, Low rotation / medium load or medium rotation / medium load state), the temperature of the three-way catalyst is equal to or higher than its activation temperature, and the air-fuel ratio (fuel injection amount) is O ₂ When feedback control is being performed, both upstream and downstream O ₂ The actual air-fuel ratio (O in exhaust gas) detected by the sensors 28 and 29 ₂ The presence / absence or degree of deterioration of the three-way catalyst is determined based on the inversion ratio of the concentration) within a certain period. Note that the inversion ratio is the upstream O in the predetermined period (hereinafter referred to as “inversion ratio detection period”). ₂ Rich lean lean inversion number A of sensor 28 and downstream O ₂ The ratio A / B with the number of inversions B of the sensor 29.
[0052]
As shown in FIG. 10, the air-fuel ratio (fuel injection amount) O ₂ When feedback control is being performed, both O ₂ The outputs of the sensors 28 and 29 repeat rich-lean reversal within the reversal ratio detection period, respectively, but if the three-way catalyst is normal, the upstream O ₂ Since the number of inversions A of the sensor 28 is considerably large, the inversion ratio (A / B) is a very large value. On the other hand, as the three-way catalyst deteriorates, the downstream O ₂ Since the number of inversions B of the sensor 29 increases, the inversion ratio (A / B) gradually decreases. Therefore, in this embodiment, the reversal ratio corresponding to the case where the exhaust gas purification rate of the three-way catalyst is reduced to 60% of the normal state (not limited to this) is set to a threshold value (hereinafter referred to as this). Is called “degradation threshold value”), the actual three-way catalyst is determined to be in a normal state if the actual reversal ratio is larger than the deterioration determination threshold value. It is determined that there is.
[0053]
As shown in FIG. 11, the relationship between the reversal ratio and the exhaust gas purification rate of the three-way catalyst was considerably different depending on the flow rate (exhaust gas amount) of the exhaust gas passing through the three-way catalyst (catalytic converter 13). It will be a thing. In FIG. 11, the exhaust gas amount increases in the order of Z 1 → Z 2 → Z 3 → Z 4. Therefore, even if the exhaust gas purification rate is the same, the inversion ratio (A / B) decreases as the exhaust gas amount increases. Thus, as shown by the curve Z3 or the curve Z4, when the exhaust gas amount is relatively large, in the vicinity of the exhaust gas purification rate (for example, 60%) where the normal state and the deteriorated state of the three-way catalyst should be distinguished, The change of the exhaust gas purification rate with respect to the change of the inversion ratio is extremely large, and it is very difficult to set the deterioration determination threshold value. Further, as shown by the curve Z1, even when the amount of exhaust gas is relatively small, the reversal ratio is in the vicinity of the exhaust gas purification rate (for example, 60%) where the three-way catalyst should be distinguished from the normal state and the deteriorated state. The change of the purification rate with respect to the change is extremely large, and it is very difficult to set the deterioration determination threshold value.
[0054]
On the other hand, as shown by the curve Z2, when the exhaust gas amount is medium, in the vicinity of the exhaust gas purification rate (for example, 60%) in which the normal state and the deteriorated state of the three-way catalyst should be distinguished, The change of the exhaust gas purification rate with respect to the change of the inversion ratio is linear and gentle, and it becomes extremely easy to set the deterioration determination threshold value. For this reason, in this embodiment, the deterioration determination threshold value THB is set in correspondence with a state where the amount of exhaust gas is medium. Therefore, it is difficult to accurately determine the deterioration of the three-way catalyst unless the amount of exhaust gas is medium, that is, when the engine 1 is at medium speed and medium load.
[0055]
In this hybrid vehicle W, the abnormality diagnosis of the evaporated fuel recovery system and the deterioration diagnosis of the three-way catalyst (hereinafter collectively referred to as “failure diagnosis”) are performed by the system controller 14. A specific failure diagnosis by the system controller 14 and control procedures of various controls accompanying this will be described according to the flowcharts shown in FIGS. The system controller 14 includes “abnormality determination means”, “abnormality determination control means”, “air-fuel ratio control means”, and “catalyst deterioration determination means” recited in the claims. And It is a comprehensive control device of the hybrid vehicle W including.
[0056]
First, the processing procedure of the operation mode setting routine which is the main routine in the failure diagnosis will be described with reference to FIGS.
As shown in FIGS. 12 to 14, in this operation mode setting routine, first, in step S1, it is determined whether or not the start switch for starting the hybrid vehicle control system is turned on, and if the start switch is not turned on ( NO), this step S1 is repeatedly executed. That is, it waits until the start switch is turned on. On the other hand, when it is determined in step S1 that the start switch is turned on (YES), in step S2, various control information such as the accelerator opening α, the battery charge state or battery voltage, the vehicle speed V, the engine water temperature, the intake air amount, and the like. Is entered.
[0057]
Next, in step S3, the basic operation mode of the hybrid vehicle W is set using, for example, a basic operation mode map as shown in FIG.
As shown in FIG. 19, in this basic operation mode map, the region R ₁ In the low output range (generally 20 to 30 km / h or less), the clutch 6 is released and the engine 1 is stopped, and the drive wheels 9 and 10 are driven only by the drive motor 2. However, when the charge amount of the battery 3 becomes equal to or less than a predetermined reference value, the engine 1 is operated. And region R ₂ In the middle output range indicated by, the clutch 6 is engaged, the engine 1 is operated in a high efficiency mode (for example, low rotation / high load), the drive motor 2 is energized, and the drive wheels 9, 10 are driven by the engine 1 and the drive. It is driven by the motor 2. Region R _Three In the high output range indicated by, the clutch 6 is engaged, the engine 1 is operated in a high output mode (for example, high rotation / high load), the drive motor 2 is energized, and the drive wheels 9, 10 are driven by the engine 1 and the drive. It is driven strongly by the motor 2.
[0058]
Here, the engine 1 is operated in a low rotation and high load range by controlling the throttle opening, the fuel injection amount, and the gear stage of the automatic transmission 7 so as to be highly efficient. . When the start switch is turned on, the engine 1 may be always operated for a predetermined period to improve the startability of the engine 1.
[0059]
Next, in step S4, it is determined whether or not the failure monitor (evaporated fuel recovery system and three-way catalyst failure diagnosis process) has ended, that is, whether or not a monitor end flag Fmf described later is 1. The If the failure monitoring is finished (YES), the hybrid vehicle W is operated in the currently set operation mode in step S5, and then returns to step S2 to continue the operation mode setting routine. Is done.
[0060]
On the other hand, if it is determined in step S4 that the failure monitoring has not ended (NO), it is determined in step S6 whether or not the engine is in the on mode, that is, the mode in which the engine 1 should be operated according to the basic operation map. It is determined whether or not there is. Here, if the engine is on (YES), in steps S7 to S9, whether or not the purge monitor flag Fparm is 1, whether or not the catalyst temperature increase flag Fcatup is 1, and the catalyst monitor flag Fcatm. Whether or not is 1 is determined.
[0061]
Here, the purge monitor flag Fparm is set to 1 when the purge monitor (evaporative fuel recovery system failure diagnosis process) is started, and is reset to 0 when the large leak determination is completed during the purge monitor. Flag. The catalyst temperature increase flag Fcatup is a flag that is set to 1 when the engine 1 is operated in the catalyst temperature increase mode. The catalyst monitor flag Fcatm is a flag that is set to 1 when the catalyst monitor (three-way catalyst deterioration diagnosis process) is being executed.
[0062]
If it is determined in steps S7 to S9 that Fparm ≠ 1, Fcatup ≠ 1, and Fcatm ≠ 1 (steps S7 to S9 are all NO), that is, if failure monitoring should be started from this time, first step In S10, a water temperature increase mode (engine temperature increase mode) is set for the engine 1, and then in step S11, a water temperature increase flag Ftwup is set to 1. The water temperature increase flag Ftwup is a flag that is set to 1 when the water temperature increase mode is set for the engine 1. In this water temperature increase mode, the engine 1 is operated in a low rotation / high load region.
[0063]
Thus, even when the engine 1 is operated in the water temperature increasing mode, the operating state of the hybrid vehicle W is in the region R in FIG. ₁ Therefore, when the engine 1 does not need to drive the drive wheels 9 and 10 in nature (when this step S10 is executed via step S15 described later), the clutch 6 is released (off). ) So that the driving force of the engine 1 is not transmitted to the drive wheels 9 and 10.
[0064]
If it is determined in step S7 that Fparm = 1 (YES), since the purge monitor mode has already been set, the process skips to step S13 described later and continues the purge monitor mode. If it is determined in step S8 that Fcatup = 1 (YES), since the catalyst temperature increase mode has already been set, the process skips to step S22 described later and the catalyst temperature increase mode is continued. . Further, if it is determined in step S9 that Fcatm = 1 (YES), the catalyst monitor mode has already been set, so the process skips to step S26 described later and the catalyst monitor mode is continued.
[0065]
Next, in step S12, it is determined whether or not the engine water temperature (engine temperature) is equal to or higher than a reference temperature (predetermined value). In this operation mode setting routine, it is difficult to perform accurate failure monitoring when the engine water temperature is lower than the reference temperature, so failure monitoring is not executed. If it is determined in step S12 that the engine water temperature is lower than the reference temperature (NO), it is not in a state in which failure monitoring can be performed, so in step S5, the hybrid vehicle W is operated in the currently set operation mode. Thereafter, the process returns to step S2, and the operation mode setting routine is continued.
[0066]
On the other hand, if it is determined in step S12 that the engine water temperature is equal to or higher than the reference temperature (YES), a failure monitor is executed. That is, first, in step S13, it is determined whether or not the hybrid vehicle W is in the vehicle high load operation mode. If it is in the vehicle high load operation mode (YES), the battery charge amount is changed to the reference charge amount (predetermined value) in step S14. ) Is determined. Here, if the battery charge amount is lower than the reference charge amount (YES), that is, when the vehicle is in a high load operation and the battery charge amount is reduced (decreased), it is not preferable to execute the failure monitor. The fault monitor is canceled. In this case, in step S5, the hybrid vehicle W is operated in the currently set operation mode, and thereafter, the operation returns to step S2 to continue the operation mode setting routine.
[0067]
If it is determined in step S13 and step S14 that the vehicle is not operating at a high load and the battery charge is not low (at least one of steps S13 to S14 is NO), a failure monitor is executed. First, in step S19, the purge monitor / large leak mode is set in the engine 1. In the purge monitor / large leak mode, the engine 1 is operated in a low rotation / medium load region suitable for purge monitoring, and sufficient intake negative pressure is generated. Even when the engine 1 is operated in the purge monitor / large leak mode in this way, the basic operation state of the hybrid vehicle W is the region R in FIG. ₁ Therefore, when the engine 1 does not essentially need to drive the drive wheels 9 and 10, the clutch 6 is released (off) so that the driving force of the engine 1 is not transmitted to the drive wheels 9 and 10. . When the hybrid vehicle W is traveling at a low speed (for example, 10 km / h or less), the clutch 6 is engaged (turned on), and the automatic transmission 7 is preferably controlled while the engine 1 and the drive motor 2 are Thus, the drive wheels 9 and 10 may be driven.
[0068]
Next, in step S20, it is determined whether or not the large leak determination has ended. If not (NO), in order to continue the large leak determination, the hybrid vehicle W is currently set in step S5. The operation mode is set, and thereafter, the process returns to step S2, and the operation mode setting routine is continued.
On the other hand, if it is determined in step S20 that the large leak determination has been completed (YES), after the purge monitor flag Fparm is reset to 0 in step S21, the deterioration diagnosis of the three-way catalyst is started in step S22 and thereafter. The The procedure or method for determining the large leak is as described above.
[0069]
In this three-way catalyst deterioration diagnosis, first, in step S22, the engine 1 is set in the catalyst temperature increase mode. At this time, small leak determination is performed in the purge monitor. Note that the procedure or method for determining the small leak is as described above. In this hybrid vehicle W, the amount of exhaust gas is medium, the temperature of the three-way catalyst (catalyst temperature) is equal to or higher than its activation temperature, and the air-fuel ratio O ₂ When the feedback control is being performed, the deterioration of the three-way catalyst is determined. Therefore, when the deterioration diagnosis is started in this way, first, in step S22, the engine 1 is set in a catalyst temperature increasing mode in which the engine 1 is operated at a low rotation and a high load so as to increase the catalyst temperature.
[0070]
Even when the engine 1 is operated in the catalyst temperature increase mode in this way, the operating state of the hybrid vehicle W is in the region R in FIG. ₁ Therefore, when the engine 1 does not essentially need to drive the drive wheels 9 and 10 (when this step S22 is executed via step S17 described later), the clutch 6 is released (off). ) So that the driving force of the engine 1 is not transmitted to the drive wheels 9 and 10.
[0071]
Next, in step S23, 1 is set to the catalyst temperature increase flag Fcatup. Subsequently, the catalyst temperature is estimated in step S24. Here, the catalyst temperature is estimated based on, for example, the engine water temperature when the engine 1 is first started after the start switch is turned on, and the integrated value of the subsequent engine operating time or the integrated value of the intake air amount. Based on the well-known method. Specifically, for example, the sum (a + b) of a value a which is a linear function (positive correlation) of the engine water temperature and a value b which is a linear function (positive correlation) of an integrated value of engine operating time or intake air amount. ) Etc., the catalyst temperature can be estimated. The catalyst temperature may be measured using a temperature sensor.
[0072]
In step S25, it is determined whether or not the catalyst temperature estimated in step S24 is equal to or higher than a predetermined value. This predetermined value is set near the activation temperature of the three-way catalyst. If it is determined in step S25 that the catalyst temperature is lower than the predetermined value (NO), the determination of deterioration of the three-way catalyst has not yet been performed. The operation is performed in the set operation mode, and then the process returns to step S2 to continue the operation mode setting routine.
[0073]
On the other hand, if it is determined in step S25 that the catalyst temperature is equal to or higher than the predetermined value (YES), the catalyst monitor mode is set in the engine 1 in step S26, and then in step S27, 1 is set in the catalyst monitor flag Fcatm. Set. In this catalyst monitor mode, the engine 1 is operated in a low rotation / medium load region (or medium rotation / medium load region) in which the amount of exhaust gas is medium suitable for determining deterioration of the three-way catalyst. Even when the engine 1 is thus operated in the catalyst monitor mode, the basic operation state of the hybrid vehicle W is the region R in FIG. ₁ Therefore, when the engine 1 does not need to drive the drive wheels 9 and 10 in nature (when this step S26 is executed via step S18 described later), the clutch 6 is released. (Off) so that the driving force of the engine 1 is not transmitted to the driving wheels 9 and 10. When the hybrid vehicle W is traveling at a low speed (for example, 10 km / h or less), the clutch 6 is engaged (turned on), and the automatic transmission 7 is preferably controlled while the engine 1 and the drive motor 2 are Thus, the drive wheels 9 and 10 may be driven. Thereafter, in step S5, the hybrid vehicle W is operated in the currently set operation mode. Thereafter, the operation returns to step S2, and the operation mode setting routine is continued.
[0074]
If it is determined in step S6 that the engine is not in the on-mode (NO), whether or not the water temperature rise flag Ftwup is 1 and the purge monitor flag Fparm is 1 in steps S15 to S18. Whether the catalyst temperature increase flag Fcatup is 1 or not and whether the catalyst monitor flag Fcatm is 1 or not are determined.
[0075]
If it is determined in steps S15 to S18 that Ftwup ≠ 1, Fparm ≠ 1, Fcatup ≠ 1, and Fcatm ≠ 1 (steps S15 to S18 are all NO), that is, the fault monitor has not ended. If the failure monitor cannot be executed, the hybrid vehicle W is operated in the currently set operation mode in step S5, and then returns to step S2 to continue the operation mode setting routine. The
[0076]
If it is determined in step S15 that Ftwup = 1 (YES), the engine 1 is already in the water temperature increase mode, so the process skips to step S10 and the water temperature increase mode is continued.
If it is determined in step S16 that Fparm = 1 (YES), the engine 1 is already in the purge monitor mode, so the process skips to step S13 and the purge monitor mode is continued.
If it is determined in step S17 that Fcatup = 1 (YES), the engine 1 is already in the catalyst temperature increase mode, so the process skips to step S22 and the catalyst temperature increase mode is continued.
If it is determined in step S18 that Fcatm = 1 (YES), the engine 1 is already in the catalyst monitor mode, so the process skips to step S26 and the catalyst monitor mode is continued.
[0077]
That is, if YES is obtained in any of steps S15 to S18, the monitor corresponding to that step is continued even though the operation of the engine 1 should be stopped in the basic operation map. (Don't give up halfway), skipping to each of the above steps, the operation of the engine 1 is continued. This increases the accuracy of each monitor.
[0078]
FIG. 20 shows an example of a change characteristic with respect to time of the vehicle speed (vehicle load) and the engine load when the operation mode setting routine is executed. In this example, the negative pressure introduction time to the evaporative fuel recovery system is approximately 20 to 30 seconds, and the time required for catalyst monitoring is approximately 2 to 3 minutes.
In FIG. 20, graph H ₁ Indicates vehicle speed, graph H ₂ Is the time t _Ten Shows the engine load when the fault monitoring is started at _Three Indicates the engine load when failure monitoring is not performed
[0079]
Hereinafter, the processing procedure of the engine control routine for controlling the fuel injection of the engine 1 and the failure diagnosis of the evaporated fuel recovery system and the three-way catalyst will be described with reference to FIGS. This engine control routine is executed every time a predetermined crank angle is reached.
As shown in FIGS. 15 to 18, in this engine control routine, first, in step S31, various data (control information) such as the intake air amount Qa, the engine water temperature Tw, the actual air-fuel ratio A / F, and the like are input.
[0080]
Next, in step S32, the operation mode to be set this time is read, and then in step S33, it is determined whether or not the engine 1 is in operation. Note that when the engine 1 is started, the control valve 40 and the purge valve 43 are closed, and the air release valve 45 is opened. If it is determined in step S33 that the engine 1 is not in operation (NO), it is not necessary to control the engine 1, and thus the current routine ends.
[0081]
If it is determined in step S33 that the engine 1 is in operation or an engine operation command is being input (YES), in steps S34 and S35, respectively, a high efficiency mode (for example, a low rotation / high load mode). Is set, and whether or not the catalyst temperature increase mode is set is determined.
If the high efficiency mode is not set (NO in step S34), steps S41 to S53 (hereinafter referred to as “purge monitor routine” for convenience) are executed. When it is determined in step S45 of this purge monitor routine that the purge monitor large leak mode is not set, steps S68 to S77 (hereinafter referred to as “catalyst monitor routine” for convenience) are executed. If the high efficiency mode is set and the catalyst temperature increase mode is set (YES in both step S34 and step S35), steps S54 to S67 (hereinafter referred to as “catalyst temperature increase routine” for the sake of convenience) are required. Executed. If none of these (YES in step S34, NO in step S35), steps S36 to S40 (hereinafter referred to as “basic operation routine” for convenience) are executed.
[0082]
Hereinafter, the basic operation routine (steps S36 to S40) will be described. In this basic operation routine, first, the high efficiency mode is set for the engine 1 in step S36. That is, the throttle opening and the fuel injection amount are set so as to achieve low rotation and high load. In this case, the throttle opening is a predetermined opening TV. ₁ Set to The fuel injection amount is set so that the actual air-fuel ratio A / F becomes the stoichiometric air-fuel ratio (A / F = 14.7) based on the intake air amount Qa and the engine speed Ne. Specifically, for example, it is proportional to the basic injection amount (k · Qa / Ne) calculated based on the intake air amount Qa and the engine speed Ne and the air-fuel ratio deviation (actual air-fuel ratio-target air-fuel ratio). The final fuel injection amount (actual fuel injection amount) is set by adding the feedback correction amount.
[0083]
Then, in step S37, the throttle valve 24 is driven, and then in step S38, it is determined whether or not it is the injection timing. If the injection timing is not reached (NO), step S38 is repeatedly executed until the injection timing is reached (wait until the injection timing is reached). When the injection timing is reached (YES), fuel injection is performed in step S39. Fuel is injected from the valve 27.
[0084]
Next, in step S40, the opening degree of the purge valve 43 is set, and the current routine ends. The opening of the purge valve 43 is preferably set based on the feedback correction amount so that the air-fuel ratio becomes the stoichiometric air-fuel ratio, that is, the air-fuel ratio does not fluctuate.
[0085]
Hereinafter, the purge monitor routine (steps S41 to S53) will be described. In this purge monitoring routine, first, in step S41, the engine 1 is set to the low rotation / medium load mode (at least the medium load mode) so as to obtain a sufficient intake negative pressure. That is, the throttle opening and the fuel injection amount are set so that the engine 1 is in a low rotation / medium load state. In this case, the throttle opening is equal to the throttle opening TV in the basic operation routine. ₁ Smaller predetermined opening TV ₂ Set to The method for setting the fuel injection amount is the same as in the basic operation routine.
[0086]
Then, in step S42, the throttle valve 24 is driven, and then in step S43, it is determined whether or not it is the injection timing. If the injection timing is not reached (NO), step S43 is repeatedly executed until the injection timing is reached. When the injection timing is reached (YES), fuel is injected from the fuel injection valve 27 in step S44.
[0087]
Next, in step S45, it is determined whether or not the purge monitor / large leak mode is set. If the purge monitor / large leak mode is not set (NO), that is, if the large leak determination has been completed, it will be described later. A catalyst monitoring routine (steps S68 to S77) is executed. On the other hand, when it is determined in step S45 that the purge monitor / large leak mode is set (YES), large leak determination is performed in steps S46 to S53. First, in step S46, the tank internal pressure P is detected, and in step S47, the control valve 40 (TPCV valve) and the purge valve 43 are opened, while the air release valve 45 is closed. That is, intake negative pressure is introduced into the evaporated fuel recovery system.
[0088]
In step S48, the first timer counter T ₁ Is incremented by one. This first timer counter T ₁ The tank internal pressure P is substantially equal to the reference pressure P from the time when the intake negative pressure is introduced into the evaporated fuel recovery system. _Ten It is a timer counter for counting the elapsed time until it decreases to (for example, -200 mmAq gauge).
[0089]
Next, in step S49, the first timer counter T ₁ Is the reference time T _Ten It is determined whether or not (for example, 30 seconds) or more. Where T ₁ ≧ T _Ten If (YES), that is, if the pressure in the evaporative fuel recovery system does not decrease easily, it is determined in step S53 that there is a large leak (abnormal determination), and a warning (alarm) is output. Thereafter, the large leak determination end flag is set in step S52.
[0090]
In step S49, T ₁ <T _Ten (NO), the tank internal pressure P is set to the reference pressure P in step S50. _Ten It is determined whether or not P ≧ P _Ten If (YES), the tank internal pressure P is still the reference pressure P _Ten Therefore, the current routine ends (engine control is continued). On the other hand, in step S50, P> P _Ten (NO), the tank internal pressure P is the reference time T. _Ten Inside the reference pressure P _Ten Since it is lower, it is determined in step S51 that there is no large leak (normal determination). Thereafter, the large leak determination end flag is set in step S52.
[0091]
Hereinafter, the catalyst temperature increase routine (steps S54 to S67) will be described. In this catalyst temperature increase routine, the small leak determination of the evaporated fuel recovery system is performed. In this catalyst temperature increasing routine, first, in step S54, the high efficiency mode is set for the engine 1. That is, the throttle opening and the fuel injection amount are set so that the engine 1 is in a low rotation / high load state. In this case, the method for setting the throttle opening and the fuel injection amount is the same as in the basic operation routine.
[0092]
Then, in step S55, the throttle valve 24 is driven, and then in step S56, it is determined whether or not it is an injection timing. If the injection timing is not reached (NO), step S56 is repeatedly executed until the injection timing is reached. When the injection timing is reached (YES), fuel is injected from the fuel injection valve 27 in step S57.
[0093]
Next, in step S58, the purge valve 43 is closed. Note that the control valve 40 (TPCV valve) remains open and the air release valve 45 remains closed. That is, the fuel vapor recovery system on the fuel tank side from the purge valve 43 is shut off from the atmosphere and sealed. Subsequently, in step S59, the small leak flag F _{S / L} Whether or not is 1 is determined. This small leak flag F _{S / L} Is a flag that is set to 1 when the small leak determination process is started and reset to 0 when the small leak determination is completed.
[0094]
In step S59, F _{S / L} If it is determined that ≠ 1 (NO), that is, if the small leak determination process is started from this time, the current tank internal pressure P is set to the initial pressure P in step S60. ₂ Is remembered as F _{S / L} If = 1 (YES), step S60 is skipped.
[0095]
Next, in step S61, the small leak flag F _{S / L} Is set to 1, and in step S62, the second timer counter T is set. ₂ Is incremented by one. This second timer counter T ₂ Is a fixed measurement time T for performing the small leak judgment of the evaporated fuel recovery system ₂₀ This is a timer counter for counting (for example, 30 seconds).
[0096]
Next, in step S63, the second timer counter T ₂ Count value is the above measurement time T ₂₀ It is determined whether or not this is the case. Where T ₂ <T ₂₀ If (NO), the measurement time T is still ₂₀ Since this time has not elapsed, the current routine is terminated (engine control is continued). On the other hand, in step S63, T ₂ ≧ T ₂₀ If it is determined (YES), the time point for determining whether or not there is a small leak has been reached, so in step S64, the current tank internal pressure P and the initial pressure P ₂ Differential pressure (PP ₂ ) Is the threshold value ΔP ₂₀ It is determined whether or not this is the case. Where (PP ₂ ) <ΔP ₂₀ If so (NO), since the negative pressure in the evaporated fuel recovery system is maintained, it is determined in step S65 that there is no small leak (normal determination). After this, in step S67, the small leak flag F _{S / L} Is reset to zero.
[0097]
On the other hand, in step S64, (PP ₂ ) ≧ ΔP ₂₀ If it is determined (YES), since air has leaked into the evaporated fuel recovery system, it is determined that there is a small leak (abnormal determination), and a warning (alarm) is output. After this, in step S67, the small leak flag F _{S / L} Is reset to zero.
[0098]
Hereinafter, the catalyst monitoring routine (steps S68 to S77) will be described. In this catalyst monitoring routine, first, in step S68, it is determined whether or not a catalyst monitoring condition is satisfied. Here, as the catalyst monitoring condition, for example, both O ₂ For example, the sensors 28 and 29 are activated, the engine water temperature Tw is equal to or higher than a predetermined value, and there is no failure in the evaporated fuel recovery system. If the catalyst monitoring condition is satisfied (YES), in step S69 the upstream side O ₂ The number of times of rich / lean reversal A within the reversal ratio detection period of the sensor 28 is counted. ₂ The rich / lean inversion number B in the inversion ratio detection period of the sensor 29 is counted.
[0099]
Next, in step S71, the upstream O ₂ The number of inversions A of the sensor 28 is a predetermined reference value A ₀ It is determined whether or not this is the case. Reference value A ₀ For example, the count time is set to a value that matches the inversion ratio detection period. In step S71, A <A ₀ (NO), the inversion ratio cannot be calculated yet, so the process skips to step S77 and the small leak flag F _{S / L} Whether or not is 1 is determined. Where F _{S / L} If ≠ 1 (NO), the current routine is terminated. On the other hand, F _{S / L} If ≠ 1 (YES), the process skips to step S58 of the catalyst temperature increase routine. This is for continuing the small leak determination if the small leak determination process is not completed even when this mode is completed in a short time after the catalyst temperature increase mode is started.
[0100]
On the other hand, in step S71, A ≧ A ₀ If it is determined (YES), since it is possible to calculate the inversion ratio, the inversion ratio HR (= A / B) is calculated in step S72. Subsequently, in step S73, it is determined whether or not the reversal ratio HR is equal to or greater than a predetermined value (degradation determination threshold value). Here, if the reversal ratio HR is greater than or equal to a predetermined value (YES), it is determined in step S74 that the three-way catalyst is normal. On the other hand, if it is determined in step S73 that the reversal ratio HR is less than the predetermined value (NO), it is determined in step S75 that the three-way catalyst is abnormal, and a warning (alarm) is output. Thereafter, in step S76, 1 is set to the determination end flag Fmf, and the current routine is ended. The determination end flag Fmf is a flag that is set to 1 when the catalyst monitoring is ended.
[0101]
In this embodiment, the abnormality determination of the evaporated fuel recovery system can be executed during this operation period when the engine 1 is first operated after the vehicle operation is started. However, instead of doing this, the engine 1 is warmed up after starting the vehicle operation (the engine 1 is operated until the engine water temperature becomes equal to or higher than a predetermined temperature), and the engine 1 is stopped for a predetermined short time. The engine 1 may be forcibly started to execute abnormality determination of the evaporated fuel recovery system.
[0102]
The hybrid vehicle W of this embodiment has the clutch 6 and controls the connection and release (disconnection) of the clutch 6 in accordance with the traveling state of the vehicle. The failure diagnosis apparatus of this embodiment can also be applied to a hybrid vehicle that is configured to be directly connected to 2 or directly connected via a speed change mechanism.
[0103]
As described above, according to this failure diagnosis method, the fuel consumption performance of the hybrid vehicle W or the engine 1 is significantly improved, and the abnormality of the evaporated fuel recovery system and the deterioration of the three-way catalyst (exhaust gas purification catalyst) are accurately and easily determined. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a schematic configuration of a hybrid vehicle according to an embodiment of the present invention.
2 is a system configuration diagram of an engine and a fuel system of the hybrid vehicle shown in FIG. 1; FIG.
FIG. 3 is a schematic diagram showing a drive configuration when the hybrid vehicle shown in FIG.
4 is a schematic diagram showing a driving mode of the hybrid vehicle shown in FIG. 1 during sudden start, sudden acceleration, or high load steady running.
FIG. 5 is a schematic diagram showing a drive mode when the engine of the hybrid vehicle shown in FIG. 1 is started.
6 is a schematic diagram showing a drive mode during deceleration of the hybrid vehicle shown in FIG. 1. FIG.
FIG. 7 is a schematic diagram showing a drive configuration during medium-load steady running of the hybrid vehicle shown in FIG. 1;
FIG. 8 is a schematic diagram showing a driving mode at the time of stopping and charging of the hybrid vehicle shown in FIG. 1;
FIG. 9 is a time chart showing various states at the time of failure diagnosis of the evaporated fuel recovery system.
FIG. 10 O ₂ It is a figure which shows the mode of the output inversion of a sensor.
FIG. 11 is a graph showing the dependency of the relationship between the output inversion ratio and the purification rate on the exhaust gas amount.
FIG. 12 is a part of a flowchart of an operation mode setting routine for failure diagnosis of the evaporated fuel recovery system and the exhaust gas purification catalyst.
FIG. 13 is a part of a flowchart of an operation mode setting routine related to failure diagnosis of the evaporated fuel recovery system and the exhaust gas purification catalyst.
FIG. 14 is a part of a flowchart of an operation mode setting routine for failure diagnosis of the evaporated fuel recovery system and the exhaust gas purification catalyst.
FIG. 15 is a part of a flowchart of an engine control routine.
FIG. 16 is a part of a flowchart of an engine control routine.
FIG. 17 is a part of a flowchart of an engine control routine.
FIG. 18 is a part of a flowchart of an engine control routine.
FIG. 19 is a diagram showing characteristics with respect to vehicle speed and accelerator opening in the basic operation mode.
FIG. 20 is a time chart showing a change characteristic with respect to time of a vehicle speed and an engine load when failure monitoring is performed.
[Explanation of symbols]
W ... hybrid vehicle, 1 ... engine, 2 ... drive motor, 3 ... battery, 4 ... engine motor, 5 ... torque converter, 6 ... clutch, 7 ... automatic transmission, 8 ... differential mechanism, 9 ... left drive wheel DESCRIPTION OF SYMBOLS 10 ... Right drive wheel, 11 ... Gear train, 12 ... Exhaust passage, 13 ... Catalytic converter, 14 ... System controller, 15 ... Electric power controller, 16 ... Accelerator pedal, 17 ... Brake pedal, 20 ... Intake passage, 21 ... Common intake passage, 22 ... air cleaner, 23 ... air flow sensor, 24 ... throttle valve, 25 ... surge tank, 26 ... independent intake passage, 27 ... fuel injection valve, 28 ... upstream O ₂ Sensor, 29 ... downstream O ₂ Sensor 31, Fuel tank 32, Fuel pump 33, Fuel supply passage 34, Fuel return passage 35, Fuel filter 36, Pressure regulator 37, Purge passage 38, Canister 39, Pressure sensor 40 Control valve, 41... Rollover valve, 43... Purge valve, 44 .. Air release passage, 45 .. Air release valve, 46.

Claims (10)

A hybrid vehicle failure diagnosis apparatus provided with an engine capable of driving each drive wheel and an electric drive motor, and traveling while changing the drive mode of the drive wheel according to the vehicle operating state Because
An evaporative fuel recovery system comprising a fuel tank, and an evaporative fuel recovery passage communicating the fuel tank and the intake passage of the engine;
An abnormality determining means for introducing a negative pressure in the intake passage into the evaporated fuel recovery system and determining an abnormality in the evaporated fuel recovery system based on a pressure change in the evaporated fuel recovery system due to the introduction of the negative pressure;
Intake air suitable for determining an abnormality of the engine so that the abnormality determination means can execute an abnormality determination of the evaporated fuel recovery system during the first engine operation in which the fuel evaporation amount in the fuel tank is small after the start of vehicle operation. A failure diagnosis apparatus for a hybrid vehicle, comprising: abnormality determination control means for operating in a predetermined abnormality determination operation state with a large negative pressure .   2. The hybrid vehicle failure diagnosis apparatus according to claim 1, wherein the abnormality determination operation state is a state in which the engine is operated in a middle rotation / medium load region. Air-fuel ratio control means for feedback-controlling the fuel supply amount to the engine is provided so that the actual air-fuel ratio becomes the target air-fuel ratio when the engine temperature is higher than a predetermined reference temperature,
3. The failure diagnosis apparatus for a hybrid vehicle according to claim 1, wherein the abnormality determination operation state is a state in which feedback control by the air-fuel ratio control means can be executed.   The failure diagnosis apparatus for a hybrid vehicle according to any one of claims 1 to 3, wherein the engine is operated during high vehicle load operation or when the battery charge amount is reduced.   The hybrid vehicle failure diagnosis apparatus according to claim 4, wherein the engine is controlled to have high efficiency during the operation.   6. The failure diagnosis apparatus for a hybrid vehicle according to claim 4, wherein the abnormality determination operation state is maintained when a high vehicle load operation is detected when the engine is in the abnormality determination operation state. .   7. The abnormality determination unit according to claim 1, wherein the abnormality determination control means forcibly starts the operation of the engine within a predetermined period after vehicle operation is started to perform abnormality determination. The fault diagnosis device for a hybrid vehicle described in 1.   The abnormality determination control means causes the engine to start high-efficiency operation when vehicle high-load operation is detected during vehicle operation, while the engine temperature remains at the predetermined reference temperature even when the vehicle high-load operation ends. The failure diagnosis device for a hybrid vehicle according to any one of claims 3 to 7, wherein the engine is continuously operated until it is determined to perform abnormality determination. An exhaust gas purification catalyst for purifying the exhaust gas of the engine, and catalyst deterioration determination means for determining deterioration of the exhaust gas purification catalyst;
The catalyst deterioration determination means continues the operation of the engine even after the introduction of the negative pressure to the evaporated fuel recovery system by the abnormality determination control means is completed, and the temperature of the exhaust gas purification catalyst becomes equal to or higher than a predetermined temperature. The failure diagnosis device for a hybrid vehicle according to any one of claims 1 to 8, wherein the deterioration determination is performed after the failure. An engine motor and a battery capable of converting engine output into electric power are provided,
10. The engine according to claim 1, wherein when the abnormality determination is performed by the abnormality determination control means, the engine output is converted into electric power to charge the battery. The failure diagnosis apparatus for a hybrid vehicle according to any one of the above.

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