JP2004124827A - Power output device and hybrid type power output device, and control method thereof, and hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of the catalyst due to the intermittent operation or deterioration of emission of the exhaust gas discharged outside in the case of intermittently operating an engine in a hybrid type power output device. <P>SOLUTION: This hybrid type power output device including an engine and a motor generator device is provided with a three-dimensional catalytic device for controlling emission of the gas, which is discharged from the engine, with the catalyst and a control unit for determining tolerance of the intermittent operation of the engine in response to emission control ratio of the catalyst as the control for lowering concentration of the harmful material contained in the gas discharged from the engine. The control unit prohibits the intermittent operation of the engine when the emission control ratio of the catalyst is the predetermined value or less. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of a hybrid power output device including an engine, a motor generator device, and the like, and a method of manufacturing the same. The present invention also belongs to the technical field of a hybrid vehicle including the hybrid power output device.
[0002]
[Background Art]
2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Literature 1 and Patent Literature 2, a so-called hybrid type power output device that is preferably mounted on a hybrid vehicle has been developed. In this type of hybrid power output device, the motor generator device is used as a generator (generator) rotated by the driving force of the engine or a dedicated power generator included in the motor generator device, as appropriate, according to the required operating state. The battery is charged using the generator. Further, the drive shaft is rotated alone or together with the engine by using the motor generator device as a motor (electric motor) that rotates by receiving power supply from a battery or by using a dedicated motor included in the motor generator device. This type of operation output device is roughly classified into a parallel hybrid system and a series hybrid system. In the former, the drive shaft is rotated by a part of the output of the engine and rotated by the driving force of the motor generator device. In the latter, the engine output is used exclusively for charging by the motor generator device, and the drive shaft is rotated by the driving force of the motor generator device. In any case, in the device, since the role of the engine is relatively reduced, remarkable effects such as a reduction in fuel consumption or a reduction in the concentration of harmful substances in exhaust gas can be obtained. .
[0003]
In such a hybrid type power output device, intermittent operation of the engine may be performed. This is because in the hybrid power output device, it is not necessary to keep the engine running at all times, as the vehicle can be driven by the cooperation of the engine and the motor generator device as described above. . In this case, during the suspension period, fuel consumption does not occur in the engine and exhaust gas is not discharged from the engine, so that low fuel consumption and low pollution can be realized better. It should be noted that the case where the suspension of the engine is permitted is specifically determined based on, for example, the degree of accelerator opening, the state of charge of the battery, or the catalyst temperature as disclosed in Patent Document 3 or the like. .
[0004]
Further, in such a hybrid type power output device, an exhaust gas purification device such as a three-way catalyst device which is widely used in a normal engine or the like is provided. According to this, NOx, HC, CO and the like present in the gas discharged from the engine are removed before reaching the outside. The existence of such an exhaust gas purification device greatly contributes to realizing a further reduction in pollution in conjunction with the reduction in the role of the engine described above.
[0005]
[Patent Document 1]
JP-A-9-47094
[Patent Document 2]
JP 2000-324615 A
[Patent Document 3]
JP-A-2000-97063
[0006]
[Problems to be solved by the invention]
However, when the intermittent operation of the engine is performed in the hybrid power output device as described above, the following problems occur with respect to the function or deterioration of the catalyst constituting the three-way catalyst device. .
[0007]
That is, when the engine is operating intermittently, it will typically experience a number of transitions from the operating period to the idle period, or vice versa, from the idle period to the operating period. At first, at the transition point of the former (that is, at the transition point from the operation period to the suspension period), the engine idles for a while after receiving the stop command. As a result, a relatively large amount of gas is sent into the exhaust pipe. Then, the catalyst of the three-way catalyst device, which is usually provided in the middle of the exhaust pipe, results in being placed in an oxygen-excess atmosphere, which causes a problem that its deterioration is accelerated.
[0008]
On the other hand, at the latter transition point (i.e., the transition point from the idle period to the operation period), the engine is usually started through a process in which ignition and combustion are executed after a predetermined idling period. The same problem as described above occurs during the idle period. Furthermore, at the time of the transition, it is difficult to maintain the ideal air-fuel ratio, so that there is a problem that incomplete combustion or the like is easily caused in the combustion chamber of the engine. This is because the flow of air in the intake pipe is indeterminate immediately after the start of the engine, and it is difficult to accurately grasp the flow rate by an air flow meter or the like provided in the intake pipe. Therefore, in this case, the gas sent into the exhaust pipe contains a relatively large amount of harmful substances generated as a result of incomplete combustion or the like. According to this, the influence on the outside (that is, the deterioration of the emission of the exhaust gas discharged to the outside) cannot be ignored.
[0009]
Such a problem is particularly serious when the deterioration of the catalyst has already progressed to a considerable extent. This is because in this case, despite the fact that a relatively large amount of gas is sent into the exhaust pipe, the insufficient function of the catalyst promotes the deterioration of the emission of exhaust gas discharged to the outside. Because it becomes.
[0010]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and when an engine is intermittently operated in a hybrid power output device, deterioration of a catalyst due to the intermittent operation, prevention of deterioration of emission of exhaust gas, etc. It is an object of the present invention to provide a hybrid-type power output device, a method of manufacturing the same, and a hybrid vehicle that enable the hybrid vehicle.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a power output device of the present invention includes: an engine; an external power supply unit that enables intermittent operation of the engine by transmitting power to the engine; Exhaust purifying means for purifying the exhaust gas by a catalyst, and control for lowering the concentration of harmful substances in the gas exhausted from the engine, according to the purification rate of the catalyst, the permissibility of the intermittent operation of the engine. A determination unit; and a control unit that controls a mode of the intermittent operation of the engine based on the acceptability determined by the determination unit.
[0012]
According to the power output apparatus of the present invention, the external power applying means is provided, which is capable of transmitting power to the engine, thereby enabling intermittent operation of the engine. Here, as a specific example of the external power applying means, a motor generator device constituting a hybrid type power output device described later can be assumed. While the engine is not idling, it is possible to envisage an engine for transmitting power to the engine in order to maintain the rotation of the engine (in this case, the vehicle is , "Eco-run vehicle that performs idle stop.") In any case, by providing such an external power applying means, in the power output device according to the present invention, it is not necessary to keep the engine running all the time. Can be operated intermittently, ie, will not be operated (to be described shortly).
[0013]
Here, in the present invention, in particular, there is provided exhaust purification means for purifying gas exhausted from the engine by a catalyst. Further, according to the present invention, as control for reducing the concentration of harmful substances in the gas discharged from the engine, determining means for determining the acceptability of the intermittent operation of the engine according to the purification rate of the catalyst, and the determining means Control means for controlling the mode of the intermittent operation of the engine based on the permissibility determined by (1).
[0014]
Here, the "intermittent operation of the engine" means that the engine is operated such that after a certain operation period, there is a pause period for a while, and then the operation period is started again. Such an operation is possible because the power output device is provided with the external power applying means as described above, and thus it is not necessary to keep the engine running at all times. In this case, during the suspension period, fuel consumption does not occur in the engine and exhaust gas is not discharged from the engine, so that low fuel consumption and low pollution can be realized better. It should be noted that the case where the suspension of the engine is permitted is specifically determined based on, for example, the degree of accelerator opening, the state of charge of the battery, and the like. The operation state in which the engine is actually stopped is taken, for example, when the vehicle starts or when the vehicle runs at a low speed.
[0015]
Next, the determination of “permissiveness” includes an alternative determination as to whether or not intermittent operation is permitted in the engine, and the content of the engine even when intermittent operation is permitted. Includes judgment on how to measure. Here, the content / degree of the intermittent operation means, for example, an operation period only after the engine stop request has been passed several times counting from the transition from the suspension period to the operation period (that is, the engine is currently in the operation state). It is possible to consider a case in which a transition process (ie, an engine stop process) from the to the suspension period is performed. In this case, it can be considered that intermittent operation of the engine is not allowed, at least only during the above-mentioned several overtakings.
[0016]
According to this, even if the intermittent operation is originally permitted, the intermittent operation is inhibited or suppressed depending on the catalyst purification rate even if the intermittent operation is permitted. Operation can be performed. In any case, in view of the above, in the present invention, during the operation period of the power output device as a whole, the transition point from the engine operation period to the suspension period, or the reverse transition point (hereinafter, both events) At the same time, the number of times of “transition point” may be represented by zero) or can be reduced. Further, according to this, a situation in which a relatively large amount of air flows into the exhaust pipe due to engine idling does not occur according to the number of reductions at the time of the transition.
[0017]
In this case, “according to the purification rate of the catalyst” specifically refers to, for example, a case where the purification rate of the catalyst has dropped considerably from the initial level, or that the purification rate of the catalyst has a predetermined value. It can be considered that the value falls below the predetermined value, or that the rate of decrease in the purification rate matches a certain level. Here, the “catalyst purification rate” is an index indicating the degree of the ability of the catalyst constituting the exhaust gas purification means to remove harmful substances contained in the exhaust gas.
[0018]
Then, the control means according to the present invention controls the mode of the intermittent operation of the engine based on the above-mentioned determination or determination of “permissibility”. Here, “controlling the mode” specifically refers to the case where the engine or the like is controlled so as to permit or prohibit the intermittent operation of the engine, or the case where the intermittent operation is permitted. This includes the case where the engine or the like is controlled so that the intermittent operation having such contents and degrees is realized. More specifically, the control target in this case includes the presence / absence or timing of ignition in a spark plug included in the engine, the fuel injection amount, the intake air amount, and the operation mode of the external power applying means (for example, , If the means is an engine, the number of revolutions thereof can also be mentioned. The “aspect” is appropriately controlled through these comprehensive processes.
[0019]
As described above, according to the present invention, it is possible to suppress the progress of catalyst deterioration depending on the catalyst purification rate. In addition, even when the deterioration of the catalyst has already progressed to a considerable extent, the intermittent operation of the engine is prohibited or suppressed, so that it is possible to prevent deterioration of the emission of exhaust gas discharged to the outside. .
[0020]
Note that, in the present invention, since the determination is not limited to “determining the acceptability of intermittent operation”, if the catalyst purification rate falls below a predetermined value, the case where “according to the catalyst purification rate” is embodied In addition, even if the actual purification rate of the catalyst falls below the predetermined value, the intermittent operation of the engine is not necessarily prohibited or suppressed. That is, if the necessity / permission of continuing the intermittent operation of the engine is still recognized depending on other conditions, it is not necessary to prohibit or suppress this. For example, when the power output device is a hybrid power output device to be described later, the power storage device such as a battery is charged by the motor generator device. If the engine is in a state of storing electric energy equal to or more than the amount of power that can be stored and the engine output cannot be transferred to the driving force, the engine should be stopped, that is, intermittent operation of the engine should still be allowed Can be considered. In addition, when there is a mode selection function that allows the driver to select a state in which the vehicle is forcibly driven only by the power of the motor, and when the state is selected, the engine should also be stopped. That is, it can be considered that intermittent operation of the engine should still be allowed.
[0021]
In one aspect of the hybrid-type power output device of the present invention, the determination unit determines the intermittent operation of the engine when the purification rate of the catalyst is equal to or less than a predetermined purification rate threshold.
[0022]
According to this aspect, when the function of the catalyst has been relatively deteriorated due to long-term use or the like, the intermittent operation of the engine can be prohibited or can be suppressed. Will be played.
[0023]
Note that, specifically, the purification rate threshold value in the present embodiment can be, for example, “the initial 95%”. That is, in this case, the prohibition of the intermittent operation of the engine or the like can be implemented when "the purification rate of the catalyst becomes 95% or less of the initial value".
[0024]
Incidentally, the specific value of such a purification rate threshold is determined in consideration of various circumstances such as the progress speed of deterioration of the catalyst itself, the use environment of the power output device, or the degree of law and regulation in the place where the power output device is used. Will be determined.
[0025]
Further, the higher the specific value of the catalyst purification rate is set, the more the above-described disadvantage at the transition point, that is, the more the emission gas emitted to the outside can be prevented from being deteriorated. If the value is set too high, the engine will almost always operate, and the essential appeal of the power output device with external power supply means that there is no need to do so is considerable. It could be reduced to some degree. In other words, it can be regarded as a matter of whether to focus on preventing emission of exhaust gas at the time of transition, or to focus on achieving low fuel consumption by stopping the engine. .
[0026]
As described above, the specific value of the catalyst purification rate is actually determined based on the above-described various situations or the difference in weight between the two facts that are in a trade-off relationship as described above.
[0027]
In this aspect, the determination means may be configured to determine that intermittent operation of the engine is prohibited when the purification rate of the catalyst is equal to or less than a predetermined purification rate threshold.
[0028]
According to such a configuration, when the purification rate of the catalyst is equal to or less than the purification rate threshold, the intermittent operation of the engine is absolutely prohibited. Therefore, in this case, since the engine does not experience the transition point after reaching this state, the situation where the exhaust gas emission is deteriorated due to the transition point does not occur. This makes it possible to provide a power output device that is less likely to cause environmental pollution.
[0029]
In addition, "prohibiting intermittent operation of the engine" means that the engine that was in the suspension period is shifted to the operation state, and then maintained in the operation state, and the engine that was in the operation period is kept in the same state. Means to maintain.
[0030]
In another aspect of the hybrid power output device of the present invention, the purification rate of the catalyst is estimated based on the degree of deterioration of the catalyst.
[0031]
According to this aspect, the catalyst purification rate is estimated based on the degree of deterioration of the catalyst. Here, the degree of deterioration of the catalyst can be, for example, a trajectory length ratio provided from an oxygen sensor provided on the upstream or downstream side of the exhaust gas purification means, and the degree of deterioration can be estimated from the trajectory length ratio. Can be. The degree of deterioration is in a certain functional relationship (generally inversely proportional) with the purification rate of the catalyst. That is, qualitatively, as the degree of deterioration increases, the purification rate of the catalyst decreases, and as the degree of deterioration decreases, the purification rate of the catalyst increases. Therefore, the purification rate of the catalyst can be estimated based on this degree of deterioration.
[0032]
In another aspect of the hybrid power output apparatus of the present invention, the purification rate of the catalyst is estimated based on the temperature of the catalyst.
[0033]
According to this aspect, the catalyst purification rate is estimated based on the temperature of the catalyst. Here, the temperature of the catalyst can be known, for example, based on the measurement result of a temperature sensor attached to the catalyst purifying means, or a parameter closely related to the temperature of the catalyst, for example, an engine speed, an intake air amount. And it can be known by estimating from rotation speed and the like. The temperature of the catalyst has a certain functional relationship with the purification rate of the catalyst. That is, qualitatively, the purification rate of the catalyst increases as the temperature increases, and the purification rate of the catalyst decreases as the temperature decreases. Therefore, the purification rate of the catalyst can be estimated based on the temperature of the catalyst.
[0034]
The purification rate of the catalyst may be estimated by using both the temperature of the catalyst and the degree of deterioration of the catalyst according to the present embodiment. In this case, there is a predetermined correlation between the degree of deterioration of the catalyst and the temperature. That is, the degree of deterioration of the catalyst generally refers to the case where the activated catalyst, in other words, the temperature is equal to or higher than a predetermined temperature and the toxic substance removing ability is stably exhibited (hereinafter, simply referred to as “stable state”). In this case, the difference in the degree of deterioration between the deteriorated catalyst and the non-degraded catalyst and the difference in the catalyst purification rate between the two are considered to be constant.
[0035]
On the other hand, for an inactive catalyst, in other words, for a catalyst that is not in a stable state at a predetermined temperature or lower, the difference in catalyst purification rate between a deteriorated catalyst and a catalyst that is not so is determined by both the catalyst temperature and the catalyst deterioration degree. Will be observed as a function of In general, among the catalysts that are not in a stable state, the catalyst purification rate of a deteriorated catalyst gradually increases with increasing temperature until the catalyst reaches the stable state, whereas a catalyst that is not so, especially a new catalyst, With this catalyst, it can be said that the stable state is immediately reached as the temperature rises, that is, the original catalyst purification rate of the catalyst is immediately achieved. Then, after the deteriorated catalyst reaches a stable state, the difference in the purification rates of the two catalysts is observed as a fixed value based on the difference in the degree of deterioration described above.
[0036]
In short, it can be said that the catalyst purification rate is preferably described as a function of both the catalyst temperature and the catalyst deterioration degree, particularly in the catalyst before activation.
[0037]
From such a fact, based on the above properties, by estimating the actual purification rate of the catalyst based on both the catalyst temperature and the catalyst deterioration degree, it is possible to know this more accurately. It goes without saying that it becomes possible. Therefore, according to such an aspect, it is possible to more reliably receive the above-described effects.
[0038]
In order to solve the above-mentioned problems, a hybrid power output device according to the present invention includes, in the power output device according to the above-described present invention (including its various aspects), an engine and an external power supply unit as the external power applying means. There is provided a motor generator device capable of generating power using at least a part of the output of the engine and capable of outputting a driving force via a drive shaft.
[0039]
According to the hybrid-type power output device of the present invention, first, a motor generator device that generates electric power by an output of an engine or outputs a driving force via a drive shaft is provided. According to the latter property, the rotation of the drive shaft can be realized not only by the motor generator device but also by the engine (parallel hybrid system). A sufficient driving force can be obtained by the assistance of the motor constituting the generator device. According to the former property (power generation), it is possible to charge the battery by borrowing the output of the engine. Therefore, the application of the driving force to the driving shaft by the motor constituting the motor generator device is special. It can be realized for a relatively long time without the need to provide a long charging period (series hybrid method).
[0040]
In any case, by relatively reducing the role of the engine that emits exhaust gas, it is possible to provide a power output device that suppresses fuel consumption and does not cause so-called environmental pollution.
[0041]
And especially in this invention, the above-mentioned motor generator apparatus is provided as said external power supply means. According to this, the intermittent operation of the engine may be performed relatively frequently as compared with the eco-run vehicle, so that a relatively large amount of air flows into the exhaust pipe due to the above-described transition point. Things can be said to be more likely. In view of this point and the point that the intermittent operation of the engine is appropriately prohibited or suppressed in the present invention, according to the present invention, the operation and effect obtained by the above-described power output device of the present invention can be more effectively enjoyed. Can be done.
[0042]
In order to solve the above-mentioned problems, a control method of a power output device of the present invention includes: an engine; an external power applying unit that enables intermittent operation of the engine by transmitting power to the engine; A method for controlling a power output device, comprising: a power output device provided with exhaust purification means for purifying gas exhausted from an engine by means of a catalyst, wherein the engine has an intermittent operation tolerance according to a purification rate of the catalyst. Judge.
[0043]
According to the power output device control method of the present invention, the above-described power output device of the present invention can be suitably operated.
[0044]
In order to solve the above-mentioned problems, a method for controlling a hybrid power output device according to the present invention can generate power using at least a part of an engine and an output of the engine and can output driving force via a drive shaft. A method for controlling a hybrid power output device for controlling a hybrid power output device including a motor generator device and exhaust gas purifying means for purifying gas exhausted from the engine by a catalyst, comprising: And determining the acceptability of the intermittent operation of the engine.
[0045]
According to the method for controlling a hybrid power output device of the present invention, the above-described hybrid power output device of the present invention can be suitably operated.
[0046]
In order to solve the above-mentioned problems, a hybrid vehicle according to the present invention includes a hybrid power output device according to the present invention, a vehicle body on which the power output device is mounted, and a drive shaft attached to the vehicle body. And a wheel driven by the driving force output through the control unit.
[0047]
According to the hybrid vehicle of the present invention, intermittent operation of the engine is inhibited or suppressed in accordance with the purification rate of the catalyst, more specifically, for example, when the purification rate of the catalyst is equal to or less than a predetermined purification rate threshold. This makes it possible to prevent the emission of the exhaust gas discharged to the outside from deteriorating.
[0048]
The operation and other advantages of the present invention will become more apparent from the embodiments explained below.
[0049]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the hybrid power output device according to the present invention is applied to a hybrid vehicle of a parallel hybrid system, and the control method of the power output device according to the present invention is executed in the hybrid vehicle. Is what is done.
[0050]
(Basic configuration and operation of hybrid vehicle)
First, the configuration of the hybrid vehicle according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram of a power system in the hybrid vehicle according to the present embodiment.
[0051]
In FIG. 1, the power system of the hybrid vehicle according to the present embodiment includes an engine 150, motor generators MG1 and MG2 constituting an example of a motor generator device, drive circuits 191 and 192 for driving these motor generators MG1 and MG2, respectively. And an EFIECU (Electrical Fuel Injection Control Unit) 170 for controlling the engine 150.
[0052]
In the present embodiment, engine 150 is a gasoline engine. Engine 150 rotates crankshaft 156. The operation of the engine 150 is controlled by the EFIECU 170. The EFIECU 170 is a one-chip microcomputer having a CPU, a ROM, a RAM, and the like therein. The CPU executes a fuel injection amount, a rotation speed, and other controls of the engine 150 according to a program recorded in the ROM. Although not shown, various sensors indicating the operating state of the engine 150 are connected to the EFIECU 170 in order to enable these controls.
[0053]
Motor generators MG1 and MG2 are configured as synchronous motor generators, and include rotors 132 and 142 having a plurality of permanent magnets on the outer peripheral surface, and stators 133 and 143 on which three-phase coils forming a rotating magnetic field are wound. Prepare. Stators 133 and 143 are fixed to case 119. The three-phase coils wound around stators 133 and 143 of motor generators MG1 and MG2 are connected to battery 194 via drive circuits 191 and 192, respectively.
[0054]
The drive circuits 191 and 192 are transistor inverters each including a pair of transistors as switching elements for each phase. The drive circuits 191 and 192 are connected to the control unit 190, respectively. When the transistors of drive circuits 191 and 192 are switched by a control signal from control unit 190, current flows between battery 194 and motor generators MG1 and MG2.
[0055]
Each of motor generators MG1 and MG2 can also operate as a motor (electric motor) that receives the supply of power from battery 194 and rotates and drives (hereinafter, this operation state is appropriately referred to as “powering”). Alternatively, when the rotors 132 and 142 are rotated by external force, the battery 194 can be charged by functioning as a generator (generator) that generates an electromotive force at both ends of the three-phase coil (hereinafter, this operation is appropriately performed). The state is called "regeneration").
[0056]
Engine 150 and motor generators MG1 and MG2 are mechanically connected via planetary gears 120, respectively. The planetary gear 120 is also called a planetary gear, and has three rotation shafts connected to respective gears described below. The gears that constitute the planetary gear 120 are a sun gear 121 that rotates at the center, a planetary pinion gear 123 that revolves around the sun gear while rotating around itself, and a ring gear 122 that rotates around the outer periphery thereof. The planetary pinion gear 123 is supported by a planetary carrier 124. In the hybrid vehicle of the present embodiment, the crankshaft 156 of the engine 150 is connected to the planetary carrier shaft 127 via the damper 130. The damper 130 is provided to absorb torsional vibration generated in the crankshaft 156. Motor generator MG 1 has rotor 132 coupled to sun gear shaft 125. Motor generator MG2 has rotor 142 coupled to ring gear shaft 126. The rotation of the ring gear 122 is transmitted to the drive shaft 112 via the chain belt 129, and further to the wheels 116R and 116L.
[0057]
Next, the operation of the power system of the hybrid vehicle according to the present embodiment configured as described above will be described.
[0058]
First, the operation of the planetary gear 120 will be described with reference to FIGS.
[0059]
The planetary gear 120 changes the rotation state of the remaining rotation shafts when the rotation speed and torque of the two rotation shafts of the three rotation shafts described above (hereinafter, both are collectively referred to as “rotation state”) are determined. It has the property of being determined. The relationship between the rotation states of the respective rotating shafts can be obtained by a calculation formula well-known in mechanics, but can also be obtained geometrically by a diagram called an alignment chart.
[0060]
FIG. 2 shows an example of the alignment chart. The vertical axis indicates the number of rotations of each rotation axis. The horizontal axis shows the gear ratio of each gear in a distance relationship. With the sun gear shaft 125 (S in the figure) and the ring gear shaft 126 (R in the figure) at both ends, a position C that internally divides between the position S and the position R into 1: ρ is defined as a position of the planetary carrier shaft 127. ρ is the ratio of the number of teeth of the sun gear 121 to the number of teeth of the ring gear 122. At the positions S, C and R defined in this way, the rotation speeds Ns, Nc and Nr of the rotation shafts of the respective gears are plotted. The planetary gear 120 has such a property that the three points thus plotted are always aligned. This straight line is called an operating collinear line. The motion collinear is uniquely determined if two points are determined. Therefore, by using the operation collinear, the rotation speeds of the remaining rotation shafts can be obtained from the rotation speeds of two rotation shafts among the three rotation shafts.
[0061]
Further, the planetary gear 120 has such a property that when the torque of each rotary shaft is replaced with a force acting on the operating collinear line, the operating collinear line is maintained as a rigid body. As a specific example, the torque acting on the planetary carrier shaft 127 is Te. At this time, as shown in FIG. 2, a force having a magnitude corresponding to the torque Te is applied to the operating collinear line at the position C from vertically downward. The acting direction is determined according to the direction of the torque Te. Further, the torque Tr output from the ring gear shaft 126 is caused to act on the operating collinear line at the position R from vertically upward. Tes and Ter in the figure are obtained by distributing the torque Te to two equivalent forces based on the distribution law of the force acting on the rigid body. There is a relationship of “Tes = ρ / (1 + ρ) × Te” and “Ter = 1 / (1 + ρ) × Te”. In consideration of the condition that the operating collinear diagram is balanced as a rigid body in the state where the above-mentioned force is applied, the torque Tm1 to be applied to the sun gear shaft 125 and the torque Tm2 to be applied to the ring gear shaft are obtained. be able to. The torque Tm1 becomes equal to the torque Tes, and the torque Tm2 becomes equal to the difference between the torque Tr and the torque Ter.
[0062]
When the engine 150 coupled to the planetary carrier shaft 127 is rotating, the sun gear 121 and the ring gear 122 can rotate in various rotation states under conditions that satisfy the above-mentioned conditions regarding the operating collinear. When sun gear 121 is rotating, it is possible to generate electric power by motor generator MG1 using the rotational power. When the ring gear 122 is rotating, the power output from the engine 150 can be transmitted to the drive shaft 112. In the hybrid vehicle having the configuration shown in FIG. 1, the power output from engine 150 is distributed to the power mechanically transmitted to the drive shaft and the power regenerated as electric power, and the regenerated electric power is used. By running the motor generator MG2 to assist the power, the vehicle can travel while outputting the desired power. Such an operation state is a state that can be taken during normal running of the hybrid vehicle. At the time of a high load such as at the time of full-open acceleration, power is also supplied from the battery 194 to the motor generator MG2 to increase the power transmitted to the drive shaft 112.
[0063]
Further, in the above-described hybrid vehicle, since the power of motor generator MG1 or MG2 can be output from drive shaft 112, the vehicle can travel using only the power output by these motors. Therefore, even when the vehicle is running, the engine 150 may be stopped or may be running idle. This operation state is a state that can be taken at the time of starting or running at low speed.
[0064]
Furthermore, in the hybrid vehicle of the present embodiment, the power output from the engine 150 can be transmitted only to the drive shaft 112 side instead of being distributed to two paths. This is an operation state that can be taken during high-speed steady running, in which motor generator MG2 is brought into a state of being rotated by inertia due to high-speed running, and runs only with power output from engine 150 without assistance by motor generator MG2.
[0065]
FIG. 3 shows an alignment chart at the time of this high-speed steady running. In the alignment chart shown in FIG. 2, the rotation speed Ns of the sun gear shaft 125 is positive, but depending on the rotation speed Ne of the engine 150 and the rotation speed Nr of the ring gear shaft 126, as shown in the alignment chart of FIG. It becomes. At this time, in motor generator MG1, the direction of rotation and the direction in which torque acts are the same, so that motor generator MG1 operates as an electric motor and consumes electric energy represented by the product of torque Tm1 and rotational speed Ns. (State of reverse power running). On the other hand, in motor generator MG2, the direction of rotation and the direction in which torque acts are opposite, so that motor generator MG2 operates as a generator and transfers electric energy represented by the product of torque Tm2 and rotational speed Nr to the ring gear shaft. It will regenerate from 126.
[0066]
As described above, the hybrid vehicle of the present embodiment can travel in various driving states based on the operation of the planetary gear 120.
[0067]
Subsequently, the control operation by the control unit 190 will be described again with reference to FIG.
[0068]
In FIG. 1, the entire operation of the power output device of the present embodiment is controlled by a control unit 190. The control unit 190 is a one-chip microcomputer having a CPU, a ROM, a RAM, and the like inside similarly to the EFIECU 170. The control unit 190 is connected to the EFIECU 170, and both can transmit various information. The control unit 190 is configured to be capable of indirectly controlling the operation of the engine 150 by transmitting information such as a torque command value and a rotation speed command value required for controlling the engine 150 to the EFIECU 170. The control unit 190 thus controls the operation of the entire power output device. In order to realize such control, the control unit 190 is provided with various sensors, for example, a sensor 144 for knowing the rotation speed of the drive shaft 112. Since the ring gear shaft 126 and the drive shaft 112 are mechanically connected, in the present embodiment, a sensor 144 for detecting the rotation speed of the drive shaft 112 is provided on the ring gear shaft 126 to control the rotation of the motor generator MG2. For the sensor.
[0069]
(Electric circuit in power system of hybrid vehicle)
Next, an electric circuit provided in the power system of the hybrid vehicle according to the present embodiment will be described in more detail with reference to FIG. That is, here, details of the control unit 190, the motor generators MG1 and MG2, the drive circuits 191 and 192, and the battery 194 shown in FIG. 1 will be described.
[0070]
As shown in FIG. 4, an inverter capacitor 196, a drive circuit 191 connected to motor generator MG1, and a drive circuit 192 connected to motor generator MG2 are connected in parallel to battery 194.
[0071]
In detail, the battery 194 includes a battery module 194a, an SMR (system main relay) 194b, a voltage detection circuit 194c, a current sensor 194d, and the like. The SMR 194b connects and disconnects the power supply of the high-voltage circuit in accordance with a command from the control unit 190, and includes two relays R1 and R2 arranged on both the positive and negative sides of the battery module unit 194a. The two relays R1 and R2 are provided on the battery 194 because the relay R2 is first turned on when the power is connected, the relay R1 is turned on subsequently, and the power is cut off, the relay R1 is turned off first. This is because it is possible to perform a reliable operation by turning off the relay R2. The voltage detection circuit 194c detects a total voltage value of the battery module 194a. The current sensor 194d detects an output current value from the battery module 194a. Output signals of the voltage detection circuit 194c and the current sensor 194d are transmitted to the control unit 190.
[0072]
Drive circuits 191 and 192 are power converters for converting high-voltage DC current of a battery and AC current for motor generators MG1 and MG2. Specifically, a three-phase bridge circuit composed of six power transistors 191a and 192a are provided, respectively, and the three-phase bridge circuits 191a and 192a convert between DC current and three-phase AC current.
[0073]
The drive circuits 191 and 192 are provided with voltage detection circuits 191b and 192b, respectively. Voltage detection circuits 191b and 192b detect back electromotive voltages of motor generators MG1 and MG2, respectively. The drive of each power transistor of the three-phase bridge circuits 191a and 192a is controlled by the control unit 190, and the drive circuits 191 and 192 send the voltage values detected by the voltage detection circuits 191b and 192b to the control unit 190. And information necessary for current control such as a current value detected by a current sensor (not shown) provided between the three-phase bridge circuits 191a and 192a and the motor generators MG1 and MG2.
[0074]
(Direct injection gasoline engine)
Next, the direct injection engine provided in the hybrid vehicle of the present embodiment will be described in more detail with reference to FIG. That is, here, the details of the engine 150 shown in FIG. 1 will be described.
[0075]
As shown in FIG. 5, engine 150 is a so-called direct injection gasoline engine that directly injects fuel into a fuel chamber. Engine 150 is controlled by EFIECU 170. The engine 150 includes the cylinder block 14. A cylinder 16 is formed inside the cylinder block 14. Although engine 150 has a plurality of cylinders, FIG. 5 shows one cylinder 16 of the plurality of cylinders for convenience of explanation.
[0076]
A piston 18 is provided inside the cylinder 16. The piston 18 can slide inside the cylinder 16 in the vertical direction in FIG. Inside the cylinder 16, a combustion chamber 20 is formed above the piston 18. In the combustion chamber 20, the injection port of the fuel injection valve 22 is exposed. During operation of the engine 150, fuel is pumped from the fuel pump 24 to the fuel injection valve 22. The fuel injection valve 22 and the fuel pump 24 are connected to the EFIECU 170. The fuel pump 24 pumps fuel to the fuel injection valve 22 according to a control signal supplied from the EFIECU 170. Further, the fuel injection valve 22 injects fuel into the combustion chamber 20 according to a control signal supplied from the EFIECU 170.
[0077]
Further, the tip of the ignition plug 26 is exposed in the combustion chamber 20. The ignition plug 26 ignites fuel in the combustion chamber 20 by receiving an ignition signal from the EFIECU 170. An exhaust pipe 30 communicates with the combustion chamber 20 via an exhaust valve 28. Each branch pipe of an intake manifold 34 communicates with the combustion chamber 20 via an intake valve 32. The intake manifold 34 communicates with a surge tank 36 on the upstream side. An intake pipe 38 communicates further upstream of the surge tank 36.
[0078]
The intake pipe 38 is provided with a throttle valve 40. The throttle valve 40 is connected to a throttle motor 42. The throttle motor 42 is connected to the EFIECU 170. The throttle motor 42 changes the opening of the throttle valve 40 according to a control signal supplied from the EFIECU 170. In the vicinity of the throttle valve 40, a throttle opening sensor 44 is provided. The throttle opening sensor 44 outputs an electric signal corresponding to the opening of the throttle valve 40 (hereinafter, appropriately referred to as throttle opening SC) to the EFIECU 170. The EFIECU 170 detects the throttle opening SC based on the output signal of the throttle opening sensor 44.
[0079]
An ignition switch 76 (hereinafter, referred to as an IG switch 76) is connected to the EFIECU 170. The EFIECU 170 detects the ON / OFF state of the IG switch 76 based on the output signal of the IG switch 76. When the IG switch 76 is turned off from the on state, the fuel injection by the fuel injection valve 22, the ignition of the fuel by the spark plug 26, and the pumping of the fuel by the fuel pump 24 are stopped, and the operation of the engine 150 is stopped. You.
[0080]
An accelerator opening sensor 80 is provided near the accelerator pedal 78. Accelerator opening sensor 80 outputs an electrical signal corresponding to the amount of depression of accelerator pedal 78 (hereinafter, appropriately referred to as accelerator opening AC) to EFIECU 170. EFIECU 170 detects accelerator opening AC based on the output signal of the accelerator opening sensor.
[0081]
In the present embodiment, a turbocharger 39 is provided in the intake pipe 38, and the compressed air is turbocharged into the intake pipe 38 by, for example, a turbine linked to a turbine provided on the exhaust pipe 30 side. It is configured as follows. Further, the rotating shaft of the turbocharger 39 is driven by a dedicated motor generator different from the motor generators MG1 and MG2, and is configured such that the boost pressure due to the turbocharging is increased by increasing the rotation speed. That is, "turbo assist" is configured to be executable. The dedicated motor generator is configured to be able to regenerate the exhaust energy of the engine 150 on the exhaust pipe 30 side by power generation. Further, the turbocharger 39 may be configured to variably increase the in-cylinder pressure at a specific timing under the control of the EFIECU 170.
[0082]
In the present embodiment, a three-way catalyst device 31 is provided in the exhaust pipe 30, and thereby the exhaust gas purification performance is enhanced. In addition, the purification performance of the three-way catalyst device 31 is significantly reduced unless the temperature is higher than a certain temperature. Therefore, a temperature sensor 31T is attached to the three-way catalyst device 31, and the catalyst temperature TCA is detected and input to the EFIECU 170 as catalyst temperature information. Alternatively, such a catalyst temperature TCA may be indirectly estimated based on other detection information such as the engine speed of the engine 150. The catalyst temperature TCA detected or estimated in this way is used for controlling the engine so that the catalyst temperature TCA does not drop below a certain temperature.
[0083]
(First Embodiment-Prohibition of Intermittent Operation of Engine Based on Deterioration of Catalyst-)
Hereinafter, a method for preventing deterioration of the emission of exhaust gas discharged to the outside by the control unit 190 and the EFIECU 170 constituting the determination means and the control means according to the present invention will be described as a first embodiment. This will be described with reference to FIG. FIG. 6 is a flowchart showing the flow of processing for preventing intermittent operation of the engine based on the degree of catalyst deterioration, thereby preventing deterioration of emission of exhaust gas discharged to the outside. FIG. 7 is a graph showing the relationship between the degree of deterioration of the catalyst constituting the three-way catalyst device 31 and the catalyst purification rate.
[0084]
In the following description, as described with reference to FIGS. 2 and 3, it is assumed that the engine 150 is operated during an intermittent operation such that the engine 150 is operated at one time and stopped at another time. . That is, in the present embodiment, the engine 150 appropriately experiences two transition points, that is, transition points from the operation period to the suspension period, and vice versa, transition points from the suspension period to the operation period, as time elapses. Is scheduled. This is because in the hybrid power output device (see FIG. 1), the vehicle can be operated by the cooperation of the engine 150 and the motor generators MG1 and MG2, so that the engine 150 does not need to be constantly operated. It depends. Note that the case where the engine 150 may be stopped here is specifically determined based on, for example, the degree of the accelerator opening AC, the state of charge of the battery 194, the catalyst temperature, and the like. The operation state in which the engine 150 is actually stopped is taken, for example, when the vehicle starts or when the vehicle runs at low speed.
[0085]
In FIG. 6, first, it is determined whether or not the catalyst purification rate exceeds a predetermined value, in other words, whether or not the catalyst purification rate is equal to or less than the predetermined value (step S11). Here, the catalyst purification rate is an index representing the degree of the ability of the catalyst constituting the three-way catalyst device 31 to remove harmful substances contained in the exhaust gas. That is, the higher the catalyst purification rate, the higher the ability of the catalyst to remove harmful substances, and the lower the catalyst purification rate, the lower the ability. Therefore, it can be considered that the catalyst purification rate is equal to or less than the predetermined value when the ability of the catalyst to remove harmful substances has reached a predetermined level or less. Here, the "predetermined value" is generally represented by a ratio when the catalyst purification rate of an ideal catalyst or a new catalyst is 100%. That is, the “predetermined value” is, for example, “95% (value corresponding to the purification rate of the new catalyst)”.
[0086]
Here, in the first embodiment, in particular, the catalyst purification rate used for the determination in step S11 is estimated from the degree of deterioration of the catalyst. That is, there is a generally inverse proportional relationship between the degree of deterioration and the catalyst purification rate as shown in FIG. 7, and as the catalyst gradually deteriorates with time (that is, as the degree of deterioration increases, ), The catalyst purification rate will decrease accordingly. As described above, the catalyst purification rate can be estimated based on the degree of deterioration. Incidentally, the degree of deterioration of the catalyst itself can be estimated from a trajectory length ratio provided from, for example, an oxygen sensor (not shown) provided on the upstream or downstream side of the three-way catalyst device 31.
[0087]
In step S11, it is determined whether or not this exceeds a predetermined value based on the catalyst purification rate estimated as described above. If this is denied, intermittent operation of the engine is prohibited. The process proceeds to step S1X, and if affirmative, proceeds to the next process (step S12).
[0088]
Here, the process of prohibiting the intermittent operation of the engine in step S1X means prohibiting the transition of the engine 150 from the operation period to the suspension period or vice versa. Specifically, the engine 150 during the suspension period is shifted to the operation period, and the state is maintained thereafter, and the engine 150 during the operation period is maintained as it is. And so on. Note that it is theoretically possible to do the opposite, that is, to continuously stop the engine 150. However, in order to enable smooth running of the vehicle thereafter, it is preferable that the engine 150 be continuously driven. In any case, the engine 150 will no longer experience a transition point.
[0089]
If it is determined in step S11 that the catalyst purification rate is not equal to or smaller than the predetermined value, the condition of other conditions for determining whether the engine intermittent operation is permitted is as follows. Is determined (step S12). Here, the “state of other conditions” means, for example, a state value or a specific value of a parameter such as an engine temperature and a water temperature, or a low charge amount of the battery 194, and when the engine 150 is stopped, the motor generators MG1 and MG2 This means whether or not there is a state as to whether or not the starting becomes difficult.
[0090]
Here, when the condition of the other condition indicates that the intermittent operation of the engine is permitted, in other words, when it is determined that the other condition for permitting the intermittent operation is satisfied. Proceeds to a process for permitting intermittent operation (step S13), otherwise proceeds to a process for prohibiting intermittent engine operation described above (step S1X). The former case means that the conventional operation assumed in the first embodiment (that is, the intermittent operation of the engine 150) is continued.
[0091]
In the above-described specific example, when the engine temperature and the water temperature are low, it is necessary to continue the warm-up operation of the engine 150. In other words, at this time, the suspension period cannot be reached, Intermittent driving would be prohibited. On the other hand, when the engine temperature and the water temperature are high, there is no particular problem even if the engine 150 is stopped, and the intermittent operation is permitted.
[0092]
According to the above processing, the following operation and effect can be obtained in the first embodiment.
[0093]
That is, when the catalyst purification rate is determined to be equal to or less than the predetermined value, the intermittent operation of the engine 150 is prohibited after the determination is made, so that the engine 150 is switched from the operation period to the suspension period, or You do not experience the transition point from the idle period to the operating period. Thus, a relatively large amount of gas is not sent to the exhaust pipe 30 due to the idling of the engine 150 inevitably occurring at the time of the transition.
[0094]
Therefore, according to the first embodiment, first, since the catalyst is not exposed to the lean atmosphere, the progress of the deterioration can be suppressed. When the catalyst purification rate is equal to or less than a predetermined value, in other words, when the catalyst can no longer be expected to exhibit a sufficient harmful substance removing function, the exhaust pipe 30 due to idling of the engine 150 as described above is connected to the exhaust pipe 30. Since a situation in which a relatively large amount of gas is sent out does not occur, it is possible to prevent the emission of exhaust gas discharged to the outside from being deteriorated.
[0095]
In the above description, the catalyst purification rate is estimated based on the degree of deterioration of the catalyst, but the present invention is not limited to such an embodiment. For example, as shown in FIG. 8, the catalyst purification rate can be estimated based on the vehicle traveling distance. Here, in FIG. 8, the catalyst purification rate decreases as the vehicle travel distance increases, and the two are almost in inverse proportion to each other, almost similarly to the degradation degree and the catalyst purification rate. It can be read. This is natural because the degree of deterioration also increases as time passes or as the vehicle travels. In addition, it goes without saying that the catalyst purification rate can be estimated based on various parameters closely related thereto.
[0096]
Further, in the above-described embodiment, the mode in which the engine intermittent operation is absolutely prohibited when the catalyst purification rate is equal to or lower than the predetermined value (see step S1X) has been described. It is not limited to the form. For example, a mode may be adopted in which intermittent operation of the engine 150 is permitted, while the content and degree of the operation are restricted. Specifically, as shown in FIG. 9, after the engine 150 has passed the engine stop request three times, counting from the transition point G <b> 1 from the most recently experienced suspension period to the operation period (the period TI and the broken arrow in the figure) For the first time, it is possible to consider a case in which a transition process from the operation period to the suspension period is performed (see reference numeral G2 in the figure). Further, following this, the engine 150 that is currently in a halt state starts to change from the halt period to the operation period only after passing the engine start request several times, counting from the transition point to the halt period from the most recently experienced operation period. It is also conceivable to continue receiving the transfer processing.
[0097]
Alternatively, it is also possible to adopt a mode in which the above-described mode is changed and the period TI is set to a certain time. That is, in this case, as described above, the engine stop request (or the engine start request) is not passed by three times as a criterion, but the engine stop request (or the engine stop request) generated during the period TI is used. Regarding the start request, regardless of the presence or absence or the number of times, the request is not responded to, and after another elapse of the period TI, the engine stop request is made within another certain period (for convenience, referred to as “period TIA”). (Or an engine start request) is accepted. In short, in this mode, the period TI and the period TIA are alternately repeated, so that the engine stop request (or the engine start request) is ignored during the period TI, and the control is not performed during the period TIA.
[0098]
In any case, in these cases, it can be said that at least the intermittent operation of the engine 150 is prohibited during the period TI in FIG. In other words, in these aspects, it can be considered that the intermittent operation of the engine is “partially” prohibited or “suppressed”. Then, during the period TI in FIG. 9, the engine 150 does not experience the transition from the operation period to the suspension period or vice versa, so that substantially the same operation and effect as described above can be obtained. Further, according to this aspect, even when viewed as the hybrid power output device as a whole, the number of times of transition in the engine 150 is reduced, so that a corresponding effect can be obtained.
[0099]
As described above, the control unit 190 and the EFIECU 170 as the determination means according to the present invention not only determine whether or not the intermittent operation of the engine 150 is permitted, but also determine how the content and the degree of the intermittent operation are permitted while permitting the intermittent operation. It may be configured to also determine whether to do so. That is, the "determining means" according to the present invention "determines the acceptability of the intermittent operation of the engine".
[0100]
(Second embodiment-prohibition of intermittent operation of engine based on catalyst temperature and catalyst deterioration degree, etc.)
In the following, another method for preventing deterioration of the emission of exhaust gas discharged to the outside by the control unit 190 and the EFIECU 170 constituting the determination means and the control means according to the present invention will be described in a second embodiment. This will be described with reference to FIGS. 10 and 11. Here, FIG. 10 is a graph showing a change in the catalyst purification rate with respect to the catalyst temperature, using the degree of deterioration of the catalyst as a parameter. FIG. 11 shows a change in the catalyst purification rate with respect to the degree of deterioration of the catalyst, using the catalyst temperature as a parameter. It is a graph.
[0101]
Now, in the second embodiment, there is no change in the processing itself shown in FIG. 6 and the method of estimating the catalyst purification rate in step S11 in FIG. 6 is different from the first embodiment. That is, in the second embodiment, the catalyst purification rate is estimated in consideration of the catalyst temperature in addition to the above-described catalyst deterioration degree. Hereinafter, this will be described in detail.
[0102]
First, there is a predetermined correlation between the degree of catalyst deterioration and the catalyst temperature. First, as shown in FIG. 10, the degree of deterioration of the catalyst generally means the activated catalyst, in other words, the ability to stably remove harmful substances at a temperature equal to or higher than a predetermined temperature (see AT in FIG. 10). (Hereinafter, simply referred to as “stable state STS”). In this case, the deteriorated catalyst (see reference symbol C1 in FIG. 10) and the catalyst that is not (refer to FIG. 10). The difference in the degree of deterioration with respect to C2) and the difference in the catalyst purification rate between the two are considered to be constant. In FIG. 10, the difference between the catalyst purification rates is indicated by reference symbol D1. Further, when this is confirmed in FIG. 11, as for any two points on the horizontal axis, that is, catalysts having different degrees of degradation W1 and W2, as long as their temperatures are the same, the difference D1 in the constant catalyst purification rate is It can be seen that it occurs.
[0103]
On the other hand, for an inactive catalyst, in other words, for a catalyst that is below the predetermined temperature AT and is not in a stable state STS, as shown in FIG. 10, the difference between the purification rate of the deteriorated catalyst and that of the catalyst that is not. D2 will be observed as a function of both catalyst temperature and catalyst degradation.
[0104]
In general, as shown in FIG. 10, among the catalysts not in the stable state STS, in the deteriorated catalyst C1, the catalyst purification rate gradually increases with increasing temperature until the stable state STS is reached. On the other hand, in the case of the catalyst C2 which is not so, especially in the case of a new catalyst, it can be said that the stable state STS is immediately reached as the temperature rises, that is, the original catalyst purification rate of the catalyst is immediately achieved. According to this, the difference between the catalyst activity rate of the deteriorated catalyst C1 and that of the non-degraded catalyst C1 from when the catalyst temperature is relatively low to the temperature at which the catalyst is activated is relatively large at first. In comparison, it can be seen that the difference gradually becomes smaller. Then, after the deteriorated catalyst C1 reaches the stable state STS, the difference between the purification rates of the two catalysts C1 and C2 is observed as a fixed one (that is, D1) based on the difference between the degrees of deterioration described above. Will be.
[0105]
In short, especially in a catalyst before activation, it can be said that it is preferable to describe the catalyst purification rate as a function of both the catalyst temperature and the degree of catalyst deterioration. And the degree of catalyst deterioration.
[0106]
Specifically, since it is known that the catalyst purification rate, the catalyst temperature, and the catalyst deterioration degree have a relationship as shown in FIGS. 10 and 11, the estimation can be made relatively easily. For example, FIG. 11 shows the relationship between the degree of deterioration and the catalyst purification rate using the catalyst temperatures T1, T2, and T3 (where T1 <T2 <T3) as a parameter. If the temperature of the catalyst and the degree of deterioration of the catalyst can be known, the catalyst purification rate is determined in principle. If the catalyst purification rate thus obtained is used, it goes without saying that the processing of step S11 in FIG. 6 can be performed in the same manner as described above. Rather, according to the second embodiment, since it is clear that the true value of the catalyst purification rate can be more accurately known, it is possible to more reliably enjoy the above-described effects. it can.
[0107]
In order to actually know the catalyst temperature, the catalyst temperature can be directly known based on the measurement result of the temperature sensor 31T shown in FIG. 5, or a parameter closely related to the catalyst temperature, for example, an engine It can be known by estimating from the number of rotations of 150, the intake air amount, the number of rotations, and the like.
[0108]
In the second embodiment, the catalyst purification rate is estimated using both the catalyst temperature and the catalyst deterioration degree. However, the present invention is not limited to such an embodiment. For example, in some cases, the catalyst purification rate can be estimated to some extent accurately based only on the catalyst temperature (see FIG. 11).
[0109]
In addition, the process regarding the permission / prohibition of the engine intermittent operation based on the catalyst purification rate described in each of the above embodiments can be used after the following modifications.
[0110]
First, the process of step S11 in FIG. 6 described above is performed at regular intervals, and whether or not the intermittent operation of the engine 150 is permitted is set / recognized as a “mode”. Such a mode can be adopted. In this case, if a transition request from the operation period to the suspension period or a reverse transition request is actually issued, the state of the mode is determined before the transition processing is actually performed based on the request. Is determined, and based on the confirmed mode, it is determined whether or not to execute the transition process. When the catalyst purification rate is maintained at a sound level, it is determined that the engine purification mode is always in the "engine intermittent operation permission mode" and the catalyst purification rate is equal to or lower than a predetermined value (step S11 in FIG. 6). After that, the engine is always in the "engine intermittent operation prohibition mode".
[0111]
Secondly, when an engine stop request or a start request actually exists, a process for permitting or rejecting intermittent operation of the engine based on the catalyst purification rate can be performed. That is, in this case, the engine 150 is being operated intermittently, and the request for transition from the operation period to the suspension period, or the reverse transition request, is as described in step S12 of FIG. 6 described above. The process is first issued based on the state of all or part of various other conditions, and based on the catalyst purification rate at the transition point whether the engine 150 is actually stopped or started. (I.e., it is close to performing the processing of step S12 in FIG. 6 first and then performing the processing of step S11 later). In this case, the process is performed every time the engine 150 actually reaches the transition point.
[0112]
Such a process can be made into a flowchart in FIG. 6 by making the following changes, for example. First, step S12 and step S11 in FIG. 6 are interchanged. Secondly, depending on the result of the exchanged step S12, the process does not immediately proceed to the engine intermittent operation prohibition process (step S1X). When all of the other conditions are satisfied, the above-described engine stop request is issued. Alternatively, a change is made in which a start request is issued, and if not, the process proceeds to the engine intermittent operation permission process (step S13 in FIG. 6). In this case, all of the "other conditions" in the replaced step S12 are given a position to receive a higher priority for the determination of permission or rejection of the engine intermittent operation than the condition related to the catalyst purification rate (step S11). Would mean.
[0113]
In the example just described, the condition in which the status to receive the priority determination is given is “all” of the other condition, but this is set as “part” of the other condition. Is also possible. In this case, the process of FIG. 6 is basically maintained, and a step of determining whether or not some of the other conditions are satisfied before step S11 is added (note that this is the case). Accordingly, the "other conditions" in step S13 include a group of conditions with some of them removed.) Then, if a positive determination is made in the newly added step, the process proceeds to step S11, and if negative, the process proceeds to step S13.
[0114]
In any case, according to these aspects, when the catalyst purification rate is no longer sufficient, the engine 150 will not experience the transition point, and it goes without saying that the above-described effects can be enjoyed in the same manner.
[0115]
In the above-described embodiment, the motor generator device includes a plurality of motor generators including synchronous motors. However, instead of or in addition to at least a part thereof, an induction motor, a vernier motor, a DC motor, a superconducting motor, It is also possible to use a motor or the like.
[0116]
In the above-described embodiment, a direct injection type gasoline engine driven by gasoline is used as the engine 150. In addition, various types of gasoline engines such as a traditional port injection type gasoline engine, a diesel engine, a turbine engine, and a jet engine are used. Of the internal combustion or external combustion engine can be used.
[0117]
In addition, the hybrid-type power output device of the present invention may be applied to vehicles of various parallel hybrid systems or various serial hybrid systems that are existing, currently being developed, or will be developed in the future.
[0118]
The present invention is not limited to the above-described embodiment, but can be appropriately modified within the scope not departing from the gist of the invention or the idea read from the entire claims and the specification. A power output device, a control method thereof, and a hybrid vehicle are also included in the technical scope of the present invention.
[0119]
【The invention's effect】
As described above, according to the hybrid power output device of the present invention, the mode of the intermittent operation of the engine is appropriately controlled in accordance with the purification rate of the catalyst, so that the exhaust gas discharged to the outside is , The risk of emission deterioration may be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of a power system in a hybrid vehicle according to an embodiment of the present invention.
FIG. 2 is an alignment chart for explaining a basic operation of the hybrid vehicle according to the embodiment.
FIG. 3 is an alignment chart when the hybrid vehicle according to the present embodiment is traveling at a high speed in a steady state.
FIG. 4 is a circuit diagram showing a configuration of a battery and a motor drive circuit of the hybrid vehicle according to the embodiment.
FIG. 5 is a schematic configuration diagram of a structure of an engine according to the present embodiment.
FIG. 6 is a flowchart showing a flow of processing for preventing intermittent operation of the engine based on the degree of catalyst deterioration, thereby preventing deterioration of emission of exhaust gas discharged to the outside.
FIG. 7 is a graph showing the relationship between the degree of deterioration of the catalyst constituting the three-way catalyst device and the catalyst purification rate.
FIG. 8 is a graph showing a relationship between a vehicle traveling distance and a catalyst purification rate.
FIG. 9 is an explanatory diagram for explaining an example of “suppressing” intermittent operation of the engine.
FIG. 10 is a graph showing a change in a catalyst purification rate with respect to a catalyst temperature, using a degree of catalyst deterioration as a parameter.
FIG. 11 is a graph showing a change in a catalyst purification rate with respect to a degree of deterioration of a catalyst, using a catalyst temperature as a parameter.
[Explanation of symbols]
20 ... Combustion chamber
26 ... Spark plug
30 ... exhaust pipe
31 ... Three-way catalyst device
31T… Temperature sensor
34… Intake manifold
150 ... Engine
170 ... EFIECU
190 ... Control unit
MG1, MG2 ... Motor generator

Claims (9)

Engine and
External power applying means for enabling intermittent operation of the engine by being capable of transmitting power to the engine;
Exhaust purification means for purifying gas exhausted from the engine by a catalyst,
Determining means for determining the acceptability of the intermittent operation of the engine according to a purification rate of the catalyst, as control for reducing the concentration of harmful substances in gas discharged from the engine;
Control means for controlling the mode of intermittent operation of the engine based on the acceptability determined by the determination means;
A power output device comprising: The power output device according to claim 1, wherein the determination unit determines the acceptability of the intermittent operation of the engine when the purification rate of the catalyst is equal to or less than a predetermined purification rate threshold. The power output device according to claim 2, wherein the determination unit determines that intermittent operation of the engine is prohibited when a purification rate of the catalyst is equal to or less than a predetermined purification rate threshold. The power output device according to any one of claims 1 to 3, wherein the purification rate of the catalyst is estimated based on a degree of deterioration of the catalyst. The power output device according to claim 1, wherein the purification rate of the catalyst is estimated based on a temperature of the catalyst. The power output device according to any one of claims 1 to 5,
As the external power applying means,
A hybrid power output device comprising: a motor generator device capable of generating power using at least a part of the output of the engine and capable of outputting a driving force via a drive shaft. A power output including an engine, external power applying means capable of intermittent operation of the engine by being capable of transmitting power to the engine, and exhaust purifying means purifying a gas discharged from the engine by a catalyst. A method for controlling a power output device for controlling a device, comprising:
A method for controlling a hybrid power output device, comprising a step of determining an allowance of an intermittent operation of the engine according to a purification rate of the catalyst. An engine, a motor generator device capable of generating power using at least a part of the output of the engine and capable of outputting a driving force via a drive shaft, and an exhaust gas purifying means for purifying gas exhausted from the engine by a catalyst. A hybrid power output device control method for controlling the hybrid power output device,
A method for controlling a hybrid power output device, comprising a step of determining an allowance of an intermittent operation of the engine according to a purification rate of the catalyst. A hybrid power output device according to claim 6,
A vehicle body on which the power output device is mounted,
A hybrid vehicle having a wheel attached to the vehicle body and driven by the driving force output via the driving shaft.

Images