JP3966141B2 - POWER OUTPUT DEVICE, HYBRID TYPE POWER OUTPUT DEVICE, CONTROL METHOD THEREOF, AND HYBRID VEHICLE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the quantity of the harmful material such as NOx contained in the exhaust gas or in the gas immediately after being discharged from an engine, independently of a possibility of realizing catalyzer warm-up in a short time. <P>SOLUTION: In a hybrid type power output device including a motor generator device, control is performed to start an increase in the quantity of the air to be fed to a combustion chamber (figure (b)) after a certain period passed after starting a processing for delaying ignition timing in an ignition plug in comparison with the ignition timing in the latest condition (figure (a)). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a power output device including an engine including a combustion chamber and a spark plug, and a hybrid power output device including a motor generator device in addition to the engine. The present invention also belongs to a technical field of an engine control method and a hybrid power output device control method, and also belongs to a technical field of a hybrid vehicle including the hybrid power output device.
[0002]
[Prior art]
In this type of engine typified by a traditional reciprocating engine, a piston connected to a crankshaft via a connecting rod (connecting rod) reciprocates throughout the entire intake, compression, expansion and exhaust processes. Such a reciprocating motion of the piston or an output mode of the engine may be appropriately adjusted for the purpose of preventing knocking or the like. Specifically, this is performed through adjustment of the ignition timing of the plug. The ignition timing is adjusted with reference to the basic ignition timing determined based on the engine intake air amount (abbreviated as “intake amount” in this specification) and the engine speed, etc. It is performed by adjusting the advance amount and the retard amount obtained by an appropriate method based on other driving conditions.
[0003]
A specific example in which such adjustment of the ignition timing is performed is disclosed, for example, in Patent Document 1. This publication discloses a technique of retarding the ignition timing in accordance with the vehicle traveling speed while idling rotation is increasing in order to promote warming up of the engine. According to this, while maintaining the engine warm-up promoting effect, it is possible to obtain an effect of preventing excessive vehicle speed and a decrease in the feeling of deceleration during low-speed traveling.
[0004]
And especially in patent document 1, since the warming-up promotion effect of an engine is maintained, the point that the warming-up promotion of the catalyst in an exhaust purification apparatus can be aimed at simultaneously is pointed out. In addition, the catalyst provided in the middle of the exhaust pipe is not activated unless the temperature is higher than a predetermined temperature, and sufficient purification performance cannot be exhibited. That is, according to the technique for retarding the ignition timing described above, the catalyst can be activated relatively early by maintaining the warm-up promoting effect.
[0005]
On the other hand, as disclosed in, for example, Patent Document 2, Patent Document 3, and the like, so-called hybrid power output apparatuses that are suitably mounted on hybrid vehicles have been developed. In this type of hybrid power output device, for example, the motor generator device is used as a generator (generator) rotated by the driving force of the engine or included in the motor generator device as appropriate according to the required operating state. Use a dedicated generator to charge the battery. 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 the battery or by using a dedicated motor included in the motor generator device. This type of operation output device is roughly divided 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 exclusively used for charging by the motor generator device, and the drive shaft is rotated by the driving force of the motor generator device.
[0006]
Even in such a hybrid type power output apparatus, as long as a normal engine is mounted, it is possible to apply the technology related to the warming-up effect mentioned above.
[0007]
[Patent Document 1]
JP-A-5-26138
[Patent Document 2]
JP-A-9-47094
[Patent Document 3]
JP 2000-324615 A
[0008]
[Problems to be solved by the invention]
However, conventional engine warm-up or catalyst warm-up has the following problems. That is, according to Patent Document 1, although it is possible to realize catalyst warm-up relatively early, there is a limit to means for retarding the ignition timing. First, it is not possible to simply take the means of retarding the ignition timing. This is because the engine speed decreases. Therefore, if the ignition timing is retarded, at the same time, usually, a method of increasing the intake air amount according to the retard amount is employed. Even if the intake amount is increased in this way, in the case of a normal engine, if the retard amount is increased too much, an engine stall may occur, and thus the amount that can be retarded is naturally limited. . In Patent Document 1, the ignition timing is retarded while the engine is cold and the idling speed is being increased, that is, while the intake air amount is increasing. There is no problem.
[0009]
However, the above-described normal method raises a new problem. That is, in the aspect in which the intake amount starts increasing simultaneously with the start of the ignition retard, first, there is a relationship between the retard amount and the intake amount that the increase in the former causes the increase in the latter. This causes a problem that the concentration of harmful substances in the gas increases. Secondly, if the amount of intake air increases, naturally a relatively large amount of exhaust gas is exhausted. At this point, however, the catalyst is not yet in an active state, so that a gas with a high concentration of harmful substances remains as it is. As a result, the amount of external emissions such as NOx increases temporarily. If attention is paid to this point, it is considered that Patent Document 1 has a further problem due to the fact that the intake amount is originally increased.
[0010]
In the above description, only NOx is mentioned, but the same problem occurs with HC contained in the exhaust gas.
[0011]
The present invention has been made in view of the above problems, and reduces the amount of harmful substances such as NOx in the exhaust gas or in the gas immediately after engine exhaust, despite the fact that catalyst warm-up can be realized at an early stage. It is an object of the present invention to provide a power output device and a hybrid power output device that can be operated, a control method for an engine and a hybrid power output device, and a hybrid vehicle.
[0012]
[Means for Solving the Problems]
  In order to solve the above problems, a power output apparatus of the present invention includes an engine including a combustion chamber and an ignition plug provided in the combustion chamber, ignition means for igniting an air-fuel mixture formed in the combustion chamber, As an intake means for sending air into the combustion chamber, an exhaust purification means for purifying the gas discharged from the combustion chamber with a catalyst, and a control for warming up the catalyst, the ignition timing of the ignition plug by the ignition means is previously set. After starting the ignition delay processing to delay the state, When the concentration of harmful substances in the gas falls below a predetermined concentration threshold,And control means for controlling the ignition means and the intake means so as to start an intake air amount increasing process for increasing the amount of air fed into the combustion chamber.
[0013]
  According to the power output apparatus of the present invention, the combustion chamber constituting the engine and the ignition plug provided in the combustion chamber, the ignition means for igniting the air-fuel mixture formed in the combustion chamber, and the intake air for feeding air into the combustion chamber Means. Furthermore, in the present invention, a control means for controlling these is provided, and the control means starts an ignition retarding process for delaying the ignition timing in the spark plug from the previous state as a control for warming up the catalyst. rear, When the concentration of harmful substances in the gas falls below a predetermined concentration threshold,It is possible to control the ignition means and the intake means so as to start an intake air amount increasing process for increasing the amount of air fed into the combustion chamber.
[0014]
According to this, first, the temperature of the gas discharged from the engine can be raised by the retard of the ignition timing. This is because so-called “afterburn” occurs in the combustion chamber due to the retard of the ignition timing. Thereby, first, warming up of the engine itself can be promoted. In particular, secondly, it is possible to promote warming up of the catalyst constituting the exhaust gas purification means for purifying the gas discharged from the combustion chamber. According to this action, for example, after the power output device is started, there is an advantage that catalyst warm-up can be completed early and the catalyst can be activated in a state where the engine is not yet warmed.
[0015]
  Further, in the present invention, after the start of the ignition delay process described above,, When the concentration of harmful substances in the gas falls below a predetermined concentration threshold,An intake air amount increasing process is performed. As a result, the following effects can be obtained. That is, when the ignition retard is executed, in order to prevent the engine speed from decreasing, it is usual to increase the intake air amount at the same time. However, if the ignition retardation and the intake air amount are increased at the same time, the concentration of harmful substances in the gas discharged from the engine alone is increased. Further, immediately after execution of the ignition retardation, the catalyst warm-up described above has not been sufficiently performed, so that removal of harmful substances such as NOx or HC cannot be performed completely. Then, the gas discharged from the combustion chamber will be discharged to the outside while containing harmful substances.
[0016]
  Therefore, in the present invention, after the ignition delay is executed,For the first time when the concentration of harmful substances in the gas discharged from the combustion chamber falls below a predetermined concentration threshold,By increasing the intake air amount, the above-described problems can be avoided. First, this is because, after the ignition retardation has sufficiently progressed, the concentration of harmful substances in the gas discharged from the combustion chamber is generally reduced regardless of the amount of intake air.Furthermore, in the case of lowering the predetermined concentration threshold value, the concentration of harmful substances in the gas exhausted from the combustion chamber is originally reduced even if the amount of exhaust gas increases as the intake air amount increases. In addition, the concentration of harmful substances in the gas finally discharged to the outside can also be reduced accordingly.
[0017]
Secondly, there is a certain elapsed time between the start point of this ignition retard and the start point of the increase in the intake air amount, so that at least catalyst warm-up during that time is promoted more than before. By. Therefore, if the elapsed time is suitably set, it is not impossible to create a state in which the catalyst is already activated when the intake air amount increases. According to this, it is possible to suppress the concentration of harmful substances in the exhaust gas finally discharged to the outside.
[0018]
As described above, according to the present invention, it is possible to reduce the concentration of harmful substances such as NOx or HC in the gas exhausted from the engine while effectively performing catalyst warm-up, thereby causing more environmental pollution. It is possible to provide a difficult hybrid type power output apparatus.
[0019]
The “engine” referred to in the present invention includes both an aspect in which spark ignition combustion is performed and an aspect in which compression self-ignition combustion is performed. However, an “engine” that performs compression auto-ignition combustion usually does not have a spark plug, and the intake air amount is normally kept constant. In the case of application to an engine to be performed, the above-described “ignition means”, “intake means” and the like may be appropriately changed. In other words, in this case, the present invention relates to an engine including a combustion chamber, ignition means for igniting an air-fuel mixture formed in the combustion chamber, fuel supply means for supplying fuel into the combustion chamber, and the combustion chamber. After starting the fuel injection retarding process for delaying the timing of the fuel supply by the fuel supply means from the previous state as the exhaust gas purification means for purifying the exhausted gas by the catalyst and the control for warming up the catalyst, And a control means for controlling the fuel supply means so as to start a fuel amount increasing process for increasing the amount of the fuel fed into the combustion chamber. It is possible to enjoy the above-described operational effects of the present invention in substantially the same manner. In such an engine that performs compression auto-ignition combustion, the ignition starts combustion at the timing when fuel is injected from the fuel injection valve to the air compressed by the piston. Therefore, the “ignition means” mentioned above can be said to be substantially synonymous with the means for injecting fuel (that is, the “fuel supply means” mentioned above).
[0022]
  BookinventionAs a means for knowing the hazardous substance concentration, it is assumed that a hazardous substance concentration detection means is specially provided as will be described later, and the harmful substance concentration is estimated using various other parameters. You may use the method of.
[0023]
  Also bookinventionExamples of the “hazardous substance” include NOx and HC. In the present specification, the term “hazardous substance” is used consistently with the above-mentioned substances as specific examples.
[0024]
  The power output device of the present inventiononeIn the aspect, after the ignition delay process is started, the control unit performs the intake air amount increasing process when the concentration of the harmful substance in the gas becomes 1/5 to 1/10 than before. The ignition means and the intake means are controlled to start the operation.
[0025]
According to this aspect, the start point of the increase in the intake amount is determined when the concentration of the harmful substance is considerably low (that is, 1/5 to 1/10) in comparison with the previous state. become. Therefore, according to this aspect, the harmful substance concentration in the exhaust gas can be more reliably suppressed.
[0026]
As described above, in the aspect of measuring the intake air amount increase timing based on the concentration of harmful substances, it is preferable to further include a harmful substance concentration detection means for detecting the concentration of harmful substances in the gas.
[0027]
According to such a configuration, it is possible to know the harmful substance concentration more directly. Therefore, in various aspects using the harmful substance concentration as described above, the determination of the start point of the increase in the intake amount is performed more effectively and appropriately. can do.
[0028]
In another aspect of the power output apparatus of the present invention, the control means starts the intake air amount increasing process when the retardation amount exceeds a predetermined retardation threshold value after starting the ignition retardation processing. And controlling the ignition means and the intake means.
[0029]
According to this aspect, the intake air amount increase is started only when the retard amount exceeds a predetermined retard threshold value, that is, when the retard has progressed to a considerable extent from the start of ignition retard processing. . In this case, the retard amount (more generally speaking, the ignition timing) and the harmful substance concentration in the gas discharged from the combustion chamber are increased if the former increases (that is, if the ignition timing is retarded more). Since the latter is known to have a certain relationship of decreasing, if the above-mentioned “retarding threshold value” is appropriately determined, the amount of harmful substances in the gas can be measured only by monitoring the retarding amount. Reduction can be estimated. For this reason, according to this aspect, it is possible to considerably reduce the concentration of harmful substances in the exhaust gas.
[0030]
In another aspect of the power output apparatus of the present invention, the control means starts the intake air amount increasing process when 1 to 3 seconds have elapsed from the start time after starting the ignition delay processing. And controlling the ignition means and the intake means.
[0031]
According to this aspect, the intake amount increase is started when a predetermined time (that is, 1 to 3 seconds) has elapsed from the start of the ignition delay processing. According to this, since it is possible to start the intake amount increase with a more reliable index, it is possible to more effectively enjoy the above-described operational effects according to the present invention.
[0032]
In the ignition delay processing, for example, the initial ignition timing is 10 to 20 ° BTDC (Before Top Dead Center) and the target ignition timing is 10 ° ATDC (After Top Dead Center) (that is, the delay is delayed). Assuming that the angular amount is 20 to 30 °, typically, for example, the processing of the retardation is performed over about 10 seconds. Assuming such a typical case, the process of starting the intake amount increase after the elapse of 1 to 3 seconds according to the present aspect provides one of extremely preferable aspects.
[0033]
In another aspect of the power output apparatus of the present invention, the control means determines whether or not to execute the ignition delay processing according to the state of the catalyst.
[0034]
According to this aspect, since the retarding process of the ignition timing for activating the catalyst is determined according to the state of the catalyst, the warming process of the catalyst can be performed effectively and appropriately. .
[0035]
In this aspect, the state of the catalyst may be estimated based on the temperature of the catalyst.
[0036]
According to such a configuration, the state of the catalyst described above is estimated based on the temperature of the catalyst. That is, if the temperature is considerably low, it can be inferred that the catalyst is in an inactive state, and if the temperature is considerably high, it can be inferred that the catalyst is already in an active state. In the former case, it can be determined that the ignition retard process is performed, and in the latter case, it is not necessary to perform the ignition retard process.
[0037]
In this configuration, in order to know the temperature of the catalyst, for example, a temperature sensor may be attached to the exhaust gas purification means, and the measurement result of the temperature sensor may be observed. Moreover, the catalyst temperature has a certain functional relationship with various parameters closely related to the temperature, even if such direct means are not used. Can be estimated indirectly. Specific examples of the various parameters include an engine speed and an intake air amount.
[0038]
Alternatively, in the aspect in which the ignition retard is executed according to the state of the catalyst, the state of the catalyst may be estimated based on the degree of deterioration of the catalyst.
[0039]
According to such a configuration, the state of the catalyst is estimated based on the degree of deterioration of the catalyst. That is, if the degree of deterioration is considerably low, it can be inferred that the catalyst is in a sufficiently functioning state, and if the degree of deterioration is considerably high, it can be inferred that the catalyst is in a state where it cannot function sufficiently. In the former case, it is possible to determine that it is not necessary to perform the ignition retard process, and in the latter case, it is necessary to perform the ignition retard process.
[0040]
In this configuration, in order to know the degree of deterioration of the catalyst, for example, a trajectory length ratio provided from an oxygen sensor provided upstream or downstream of the exhaust purification means can be used, and the degree of deterioration is , And can be estimated from the locus length ratio. Further, a hazardous substance concentration detection means is provided downstream of the exhaust purification means, and the detection result can be used. The deterioration degree is judged to be large when the harmful substance concentration is high. If it is low, it can be judged as small.
[0041]
Furthermore, in order to know the state of the catalyst, it is needless to say that both the degree of deterioration of the present configuration and the temperature of the catalyst described above are used. According to this, it goes without saying that the "catalyst state" can be determined with higher accuracy.
[0042]
In order to solve the above problems, a hybrid power output device of the present invention uses at least a part of the output of the engine in the power output device of the present invention described above (however, including various aspects thereof). A motor generator device capable of generating electric power and outputting a driving force via a drive shaft is further provided.
[0043]
In another aspect of the hybrid type power output apparatus of the present invention, a motor generator apparatus that generates electric power by the output of the engine or outputs a driving force via a driving shaft is provided. Among these, according to the latter property, the rotation of the drive shaft can be realized by the engine as well as by the engine (parallel hybrid system). For example, even if the output of the engine is low, the motor Sufficient driving force can be obtained with the assistance of the motor constituting the generator device. In addition, 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 drive shaft by the motor constituting the motor generator device is special. This makes it possible to achieve this over a relatively long period of time without requiring a long charging period (series hybrid method).
[0044]
In any case, by relatively reducing the role of the engine that discharges exhaust gas, it is possible to provide a power output device that suppresses fuel consumption and does not cause so-called environmental pollution.
[0045]
In one aspect of the hybrid type power output apparatus of the present invention, the control means at least at a point in time from the start of the ignition retard process to the start of the intake air amount increase process. The number of revolutions of the engine is controlled by the device.
[0046]
According to this aspect, the engine speed is adjusted by the motor generator device at least at a temporary point after the ignition delay processing is started and before the intake air amount increase processing is started. Here, according to the present invention, in general, the advance of the delay angle is performed first and the increase in the intake air amount is delayed, so there is a predetermined elapsed time between the two. In this case, the engine speed may decrease during the elapsed time. According to this, there is a possibility of adversely affecting the operation of the hybrid power output device and the operation of a vehicle or the like equipped with the hybrid power output device.
[0047]
However, according to this aspect, at least during the above-described elapsed time, the control means controls the engine speed by using the motor generator device. That is, when the engine speed decreases as described above, the motor generator device can perform an assist to compensate for this.
[0048]
Therefore, according to this aspect, it is possible to extremely reduce the possibility that the operation of the hybrid type power output apparatus and the operation of the vehicle or the like on which the hybrid power output apparatus is operated will be irregular during the elapsed time.
[0049]
In this aspect, the control means controls the rotational speed of the engine by the motor generator device until the ignition delay processing is completely completed.
[0050]
According to such a configuration, the assist to the engine by the motor generator device described above is performed while the retard processing is being executed. Therefore, according to this configuration, it is possible to more reliably enjoy the above-described operational effects.
[0051]
In another aspect of the power output apparatus of the present invention, the control means starts the intake air amount reduction process for returning the amount of air fed into the combustion chamber from the increased state to the previous state, and then in the spark plug. The ignition means and the intake means are controlled so as to start an ignition advance processing for advancing the ignition timing from a retarded state.
[0052]
According to this aspect, in order to control the catalyst warm-up, the ignition timing is retarded and the intake timing is advanced and the intake air amount is decreased as viewed from the state in which the intake amount is increased. Become. In short, according to this aspect, the state in which the catalyst is warmed up by the execution of the ignition delay described above is returned to the previous state.
[0053]
Here, in this embodiment, in particular, the ignition timing advance processing is performed before the intake amount reduction processing.
[0054]
Here, it is known that there is a certain relationship between the amount of intake air and the concentration of harmful substances in the gas discharged from the combustion chamber. If it is reduced, the concentration of harmful substances in the gas can be sufficiently reduced. On the other hand, as described above, the retard amount and the harmful substance concentration have a certain relationship that the latter decreases as the former increases, that is, the latter increases as the former decreases. If you proceed, the concentration of harmful substances will increase. In other words, according to this aspect, the increase in the harmful substance concentration is caused by the execution of the ignition advance, but before that, by reducing the harmful substance concentration by sufficiently reducing the intake air amount, If the effect is made to exceed the former effect, it will be possible to achieve a net reduction in the concentration of harmful substances.
[0055]
In this regard, if the reduction of the intake air amount and the ignition advance angle are performed simultaneously, there are the following disadvantages. That is, in this case, since the intake air amount has just started to decrease at the start stage of the ignition advance angle, a state where a relatively large amount of air is still sent into the combustion chamber is created. From the relationship between the amount of intake air and the concentration of harmful substances, there is a greater risk that exhaust gas with a high concentration of harmful substances will be exhausted.
[0056]
However, in this aspect, the intake air amount is reduced first, and then the ignition advance is executed. Therefore, the above-described problem does not occur.
[0057]
In this aspect, the control means controls the ignition means and the intake means so as to start the ignition advance processing when the amount of air falls below a predetermined threshold after starting the intake air amount reduction process. To do.
[0058]
According to such a configuration, the above-described ignition advance is started when the intake air amount falls below a predetermined threshold value. Therefore, if the predetermined threshold value is appropriately determined, the above-described effects can be more reliably achieved. It is possible to enjoy it.
[0059]
In addition, the actual detection of the state “the amount of air falls below a predetermined threshold” in this aspect can be realized by, for example, observing the amount of air itself, It can also be realized by estimating from various other parameters closely related to. Furthermore, for at least one of these various parameters, a threshold value unique to the parameter is set in advance, and when the parameter falls below or exceeds the threshold value, the state itself that “the amount of air falls below the predetermined threshold value” May be estimated.
[0060]
In addition, the above-described two aspects including the intake air amount reduction process and the ignition advance process can naturally be applied to the above-described hybrid power output apparatus of the present invention.
[0061]
In order to solve the above-described problems, a hybrid vehicle of the present invention includes the above-described hybrid power output device of the present invention (including various aspects thereof), a vehicle body body on which the power output device is mounted, And a wheel that is attached to the vehicle body and driven by the driving force output through the drive shaft.
[0062]
According to the hybrid vehicle of the present invention, the hybrid type power output apparatus of the present invention described above is provided, so that it is possible to reduce the concentration of harmful substances while promoting catalyst warm-up.
[0063]
  In order to solve the above-described problems, an engine control method of the present invention is a control method for controlling an engine including a combustion chamber and a spark plug provided in the combustion chamber. A first step of delaying from the state of the second step, and a second step of increasing the amount of air sent into the combustion chamberAnd a third step of returning the amount of air sent into the combustion chamber to a previous state, and a fourth step of advancing the ignition timing in the spark plug from a retarded state.And the start time of the second step is later than the start time of the first step.In addition, the fourth step is performed after the start of the third step.
[0064]
  According to the engine control method of the present invention, similar to the power output device of the present invention described above, early activation of the catalyst can be realized by executing the ignition retard. Also, since the intake air amount increase (second step) starts after the ignition retard processing (first step) starts, the concentration of harmful substances in the gas discharged from the combustion chamber is reduced. can do.Further, similarly to the above-described aspect of the hybrid type power output apparatus of the present invention, the above-described ignition retarded state and large intake air amount state are returned to the previous state. Is executed after the intake air amount reducing step (third step), it is possible to reduce the concentration of harmful substances in the gas discharged from the combustion chamber. .
[0067]
In order to solve the above-described problem, the hybrid power output apparatus control method of the present invention is the same as the above-described engine control method of the present invention (including various aspects thereof). A motor generator device capable of generating electric power using at least a part of the motor generator and outputting a driving force via a drive shaft, and connected to the engine by the motor generator device at least at one point of the first step. A step of controlling the number of rotations.
[0068]
According to the control method of the hybrid type power output device of the present invention, the motor generator controls the engine speed at least at a temporary point during the ignition delay processing (first step). Done. According to this, since it is possible to assist the motor generator device so as to compensate for the decrease in the engine speed accompanying the ignition delay processing, the hybrid type power that can occur during the execution of the ignition retardation processing. It is possible to suppress irregular operations of the output device and irregular operations of a vehicle or the like on which the output device is mounted.
[0069]
Such an operation and other advantages of the present invention will become apparent from the embodiments described below.
[0070]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the hybrid power output apparatus according to the present invention is applied to a parallel hybrid hybrid vehicle, and the control method for the power output apparatus according to the present invention is executed in the hybrid vehicle. It is what is done.
[0071]
(Basic configuration and operation of hybrid vehicle)
First, the structure of the hybrid vehicle of this embodiment is demonstrated using FIG. FIG. 1 is a block diagram of a power system in the hybrid vehicle of this embodiment.
[0072]
In FIG. 1, the power system of the hybrid vehicle of 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 a control unit 190 for controlling the drive circuits 191 and 192, and an EFIECU (Electrical Fuel Injection Engine Control Unit) 170 for controlling the engine 150.
[0073]
In the present embodiment, the engine 150 is a gasoline engine.
[0074]
Engine 150 rotates crankshaft 156. The operation of engine 150 is controlled by EFIECU 170. The EFIECU 170 is a one-chip microcomputer having a CPU, ROM, RAM, etc. therein, and the CPU executes control of the fuel injection amount, the rotational speed, and the like of the engine 150 in accordance with a program recorded in the ROM. Although not shown, various sensors that indicate the operation state of the engine 150 are connected to the EFIECU 170 in order to enable these controls.
[0075]
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 wound with a three-phase coil that forms a rotating magnetic field. Prepare. The stators 133 and 143 are fixed to the case 119. 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.
[0076]
The drive circuits 191 and 192 are transistor inverters each including two 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, a current flows between battery 194 and motor generators MG1 and MG2.
[0077]
Each of motor generators MG1 and MG2 can also operate as a motor (electric motor) that rotates by receiving power supplied from battery 194 (hereinafter, this operating state is referred to as “powering” as appropriate). Alternatively, when the rotors 132 and 142 are rotated by an external force, the battery 194 can be charged by functioning as a generator (generator) that generates electromotive force at both ends of the three-phase coil (hereinafter, this operation is appropriately performed). The state is called “regeneration”).
[0078]
Engine 150 and motor generators MG1 and MG2 are mechanically coupled via planetary gear 120, respectively. Planetary gear 120 is also called a planetary gear, and has three rotating shafts coupled to the gears shown below. The gears constituting the planetary gear 120 are a sun gear 121 that rotates at the center, a planetary pinion gear 123 that revolves while rotating around the periphery of the sun gear, and a ring gear 122 that rotates at the outer periphery thereof. The planetary pinion gear 123 is pivotally supported by the planetary carrier 124. In the hybrid vehicle of this embodiment, the crankshaft 156 of the engine 150 is coupled to the planetary carrier shaft 127 via the damper 130. The damper 130 is provided to absorb torsional vibration generated in the crankshaft 156. Rotor 132 of motor generator MG1 is coupled to sun gear shaft 125. Rotor 142 of motor generator MG2 is coupled to ring gear shaft 126. The rotation of the ring gear 122 is transmitted to the drive shaft 112 and further to the wheels 116R and 116L via the chain belt 129.
[0079]
Next, the operation in the power system of the hybrid vehicle of the present embodiment configured as described above will be described.
[0080]
First, the operation of the planetary gear 120 will be described with reference to FIGS.
[0081]
In the planetary gear 120, when the rotation speed and torque of the two rotation shafts among the three rotation shafts described above are determined (hereinafter appropriately referred to as “rotation state”), the rotation state of the remaining rotation shafts is determined. It has the property of being determined. The relationship between the rotational 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 a collinear diagram.
[0082]
FIG. 2 shows an example of an 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. The sun gear shaft 125 (S in the figure) and the ring gear shaft 126 (R in the figure) are taken at both ends, and the position C that internally divides the position S and the position R into 1: ρ is the 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. The rotation speeds Ns, Nc and Nr of the rotation shafts of the respective gears are plotted at the positions S, C and R thus defined. The planetary gear 120 has the property that the three points plotted in this way are always aligned. This straight line is called an operation collinear line. The movement collinear line is uniquely determined if two points are determined. Therefore, by using the operation collinear line, the rotation speed of the remaining rotation shafts can be obtained from the rotation speeds of the two rotation shafts among the three rotation shafts.
[0083]
The planetary gear 120 has the property that when the torque of each rotating 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, a torque acting on the planetary carrier shaft 127 is assumed to be Te. At this time, as shown in FIG. 2, a force having a magnitude corresponding to the torque Te is applied to the operation collinear line from the vertical bottom to the top at the position C. The direction to be applied 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 operation collinear line at the position R from vertically above to below. Tes and Ter in the figure are obtained by distributing the torque Te into 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 operation nomogram is balanced as a rigid body in the state where the above forces are applied, a torque Tm1 to be applied to the sun gear shaft 125 and a torque Tm2 to be applied to the ring gear shaft are obtained. be able to. The torque Tm1 is equal to the torque Tes, and the torque Tm2 is equal to the difference between the torque Tr and the torque Ter.
[0084]
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 rotational conditions under the conditions that satisfy the above-described conditions regarding the operation collinearity. When the sun gear 121 is rotating, electric power can be generated by the 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 the 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 driving the motor generator MG2 to assist the power, the vehicle can travel while outputting desired power. Such an operating state is a state that can be taken during normal traveling of the hybrid vehicle. When the load is high, such as during full-open acceleration, electric power is also supplied from the battery 194 to the motor generator MG2 to increase the power transmitted to the drive shaft 112.
[0085]
In the hybrid vehicle described above, since the power of motor generator MG1 or MG2 can be output from drive shaft 112, it is possible to travel using only the power output by these motors. Therefore, even when the vehicle is traveling, the engine 150 may be stopped or may be in a so-called idle operation. This operation state is a state that can be taken when starting or running at a low speed.
[0086]
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 the two paths. This is an operational state that can be taken during high-speed steady traveling, where the motor generator MG2 is driven by inertia due to high-speed traveling, and travels only with the power output from the engine 150 without assistance from the motor generator MG2.
[0087]
FIG. 3 shows a nomographic chart at the time of this high-speed steady running. In the alignment chart shown in FIG. 2, the rotational speed Ns of the sun gear shaft 125 is positive. However, the rotational speed Ns of the engine 150 and the rotational speed Nr of the ring gear shaft 126 are negative as shown in 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 motor generator MG1 operates as an electric motor and consumes electrical energy represented by the product of torque Tm1 and rotation speed Ns. (Reverse power running state). On the other hand, in motor generator MG2, the direction of rotation and the direction in which torque acts are reversed, so that motor generator MG2 operates as a generator, and the electric energy represented by the product of torque Tm2 and rotation speed Nr is transferred to the ring gear shaft. It will regenerate from 126.
[0088]
Thus, the hybrid vehicle of this embodiment can travel in various driving states based on the action of the planetary gear 120.
[0089]
Subsequently, the control operation by the control unit 190 will be described with reference to FIG. 1 again.
[0090]
In FIG. 1, the entire operation of the power output apparatus of this 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 in the same manner as 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 able to indirectly control the operation of the engine 150 by transmitting information such as a torque command value and a rotation speed command value necessary for controlling the engine 150 to the EFIECU 170. The control unit 190 thus controls the operation of the entire power output apparatus. 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 ring gear shaft 126 and drive shaft 112 are mechanically coupled, in this embodiment, sensor 144 for determining the rotational speed of drive shaft 112 is provided on ring gear shaft 126 to control the rotation of motor generator MG2. It is common with the sensor for.
[0091]
(Electric circuit in power system of hybrid vehicle)
Next, with reference to FIG. 4, the electric circuit provided in the power system of the hybrid vehicle of this embodiment will be described in more detail. 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.
[0092]
As shown in FIG. 4, inverter capacitor 196, drive circuit 191 connected to motor generator MG1, and drive circuit 192 connected to motor generator MG2 are connected in parallel to battery 194, respectively.
[0093]
Specifically, the battery 194 includes a battery module unit 194a, an SMR (system main relay) 194b, a voltage detection circuit 194c, a current sensor 194d, and the like. The SMR 194b connects / cuts off the power supply of the high voltage circuit according to a command from the control unit 190, and is composed of two relays R1 and R2 arranged at the + and-both poles of the battery module unit 194a. The battery 194 is provided with two relays R1 and R2. When the power is connected, the relay R2 is first turned on, then the relay R1 is turned on. When the power is shut off, the relay R1 is first turned off, This is because a reliable operation can be performed by turning off the relay R2. The voltage detection circuit 194c detects the total voltage value of the battery module unit 194a. The current sensor 194d detects an output current value from the battery module unit 194a. Output signals of the voltage detection circuit 194c and the current sensor 194d are transmitted to the control unit 190.
[0094]
The drive circuits 191 and 192 are power converters that convert the high voltage direct current of the battery and the alternating current for the motor generators MG1 and MG2, and more specifically, a three-phase bridge circuit composed of six power transistors. 191a and 192a are provided, respectively, and conversion between a direct current and a three-phase alternating current is performed by the three-phase bridge circuits 191a and 192a.
[0095]
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 driving of the power transistors of the three-phase bridge circuits 191a and 192a is controlled by the control unit 190, and the voltage values detected by the voltage detection circuits 191b and 192b from the driving circuits 191 and 192 to the control unit 190 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 is transmitted.
[0096]
(Direct injection gasoline engine)
Next, with reference to FIG. 5, the direct injection engine provided in the hybrid vehicle of the present embodiment will be described in more detail. That is, the details of the engine 150 shown in FIG. 1 will be described here.
[0097]
As shown in FIG. 5, the engine 150 is a so-called direct injection gasoline engine that directly injects fuel into the fuel chamber. Engine 150 is controlled by EFIECU 170. The engine 150 includes a cylinder block 14. A cylinder 16 is formed inside the cylinder block 14. Although the engine 150 includes a plurality of cylinders, for convenience of explanation, FIG. 5 shows one cylinder 16 among the plurality of cylinders.
[0098]
A piston 18 is disposed inside the cylinder 16. The piston 18 can slide in the vertical direction in FIG. 5 inside the cylinder 16. 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 side in accordance with a control signal supplied from the EFIECU 170. The fuel injection valve 22 injects fuel into the combustion chamber 20 in accordance with a control signal supplied from the EFIECU 170.
[0099]
Further, the tip of the spark plug 26 is exposed in the combustion chamber 20. The spark plug 26 ignites the 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 the surge tank 36 on the upstream side. An intake pipe 38 communicates further upstream of the surge tank 36.
[0100]
A throttle valve 40 is disposed in the intake pipe 38. 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 degree of the throttle valve 40 in accordance with a control signal supplied from the EFIECU 170. A throttle opening sensor 44 is disposed in the vicinity of the throttle valve 40. The throttle opening sensor 44 outputs an electrical signal corresponding to the opening of the throttle valve 40 (hereinafter referred to as the throttle opening SC as appropriate) to the EFIECU 170. The EFIECU 170 detects the throttle opening SC based on the output signal of the throttle opening sensor 44.
[0101]
An ignition switch 76 (hereinafter referred to as IG switch 76) is also 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 changed from the on state to the off state, the fuel injection by the fuel injection valve 22, the ignition of the fuel by the ignition plug 26, and the fuel pumping by the fuel pump 24 are stopped, and the operation of the engine 150 is stopped. The
[0102]
In the vicinity of the accelerator pedal 78, an accelerator opening sensor 80 is disposed. The accelerator opening sensor 80 outputs an electric signal corresponding to the depression amount of the accelerator pedal 78 (hereinafter referred to as accelerator opening AC as appropriate) to the EFIECU 170. The EFIECU 170 detects the accelerator opening AC based on the output signal of the accelerator opening sensor.
[0103]
In the present embodiment, the intake pipe 38 is provided with a turbocharger 39. For example, the compressed air is turbocharged into the intake pipe 38 by a turbine linked to the turbine provided on the exhaust pipe 30 side. It is configured as follows. Further, the rotation shaft of the turbocharger 39 is driven by a dedicated motor generator different from the motor generators MG1 and MG2, and the boost pressure due to turbocharging is increased by increasing the number of rotations. That is, “turbo assist” is configured to be executable. The dedicated motor generator is configured such that the exhaust energy of the engine 150 on the exhaust pipe 30 side can be regenerated 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.
[0104]
In the present embodiment, the exhaust pipe 30 is provided with a three-way catalyst device 31, thereby improving the exhaust gas purification performance. Note that 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 catalyst temperature TCA may be estimated indirectly based on other detection information such as the engine speed in engine 150. The catalyst temperature TCA detected or estimated in this way is used for engine control so that the catalyst temperature TCA does not drop below a certain temperature.
[0105]
(Catalyst warm-up control-Start of catalyst warm-up control-)
Hereinafter, a method of suitably warming the three-way catalyst device 31 by the control unit 190 and the EFIECU 170 constituting the control means according to the present invention will be described with reference to FIGS. FIG. 6 is a flowchart showing the flow of processing of the method for performing the catalyst warm-up and the ignition / intake amount control method executed in association therewith. FIG. 7 shows the catalyst warm-up process according to the present embodiment through changes in various parameters. (A) shows the change in the retard amount of the ignition timing according to the time progress, and (b) shows the time progress. (C) is a characteristic diagram showing the change in the NOx concentration in the exhaust gas with the progress of time, respectively.
[0106]
In FIG. 6, it is first determined whether or not catalyst warm-up control is necessary (step S11). Specifically, the current temperature of the three-way catalyst device 31 is confirmed based on the measurement result provided by the temperature sensor 31T shown in FIG. 5, and if this is lower than a predetermined value, warm air is required, and vice versa. Therefore, it is determined that warm air is unnecessary. In the former case, the process proceeds to a new process for realizing catalyst warm-up (from step S11 to step S12). In the latter case, catalyst warm-up control is terminated (from step S11 to step END). . The case where the former process is selected is typically considered immediately after the power output apparatus according to this embodiment is started.
[0107]
In the above, the current temperature of the three-way catalyst device 31 is confirmed based on the direct measurement result by the temperature sensor 31T, but the present invention is not limited to such a form. That is, in order to confirm the current temperature of the three-way catalyst device 31, for example, if another parameter closely related to the temperature is confirmed, the temperature can be estimated from the parameter. Specifically, the temperature of the three-way catalyst device 31 and the cooling water temperature of the engine 150, the intake air amount, the rotational speed, and the like have a certain functional relationship. Therefore, the current temperature of the three-way catalyst device 31 can be estimated by using the various values exemplified above.
[0108]
Further, the present invention is not limited to the “catalyst temperature”. That is, in the present invention, it is possible to determine whether or not to perform catalyst warm-up using the degree of deterioration of the catalyst that can be known by using an oxygen sensor or the like provided in the exhaust pipe 30.
[0109]
In short, in the present invention, it is possible to determine whether or not the catalyst warm-up is performed based on the “catalyst state” more broadly (that is, the process according to step S11 in FIG. 6 is performed).
[0110]
Next, it is determined whether or not the catalyst warm-up control is actually allowed (step S12). This is performed based on how much the accelerator opening degree AC is. Here, the accelerator opening degree AC is used as an indicator of whether or not the catalyst warm-up control is performed. If the accelerator opening degree AC is larger than a predetermined value, the output required for the engine 150 becomes large. This is because, in such a situation, since a large amount of high-temperature exhaust gas is supplied to the catalyst, it can be said that there is no need to carry out catalyst warm-up control. When such a condition is satisfied, the process proceeds to a new process for realizing catalyst warm-up (from step S12 to step S13). Otherwise, the catalyst warm-up control is terminated (step S12). To step END).
[0111]
As described above, when it is recognized that the catalyst needs to be warmed up (step S11) and the situation is acceptable (step S12), the ignition timing is subsequently retarded (step S13). . That is, the EFIECU 170 gradually delays the timing of ignition in the spark plug 26 by adjusting the supply mode of the ignition signal.
[0112]
In practice, this ignition retardation is gradually performed as shown in FIG. 7A (indicated as “gradual change” in step S13 of FIG. 6). Here, “gradually” specifically means, for example, that the ignition timing is 10 to 20 ° BTDC at the start point of the ignition delay indicated by the symbol S in FIG. In the case where the ignition timing at the time of completion of the retardation indicated by the symbol E in (a) is 10 ° ATDC, the retardation processing is executed so that the interval between these SEs is approximately 10 seconds.
[0113]
By retarding the ignition timing in this way, so-called “post-combustion” occurs in the combustion chamber 20, and accordingly, the gas discharged from the combustion chamber 20 to the exhaust pipe 30 has a higher temperature. Will be. As described above, in the present embodiment, first, the temperature increase (that is, activation of the catalyst) of the three-way catalyst device 31 is promoted.
[0114]
Now, when the ignition retard is started in this way, subsequently, in the present embodiment, in particular, as a premise for increasing the intake air amount, it is confirmed how much the retard amount is (step S14). . Hereinafter, the significance of the confirmation of the retardation amount will be described with reference to FIG. FIG. 8 is a graph showing the relationship between the ignition timing (or retard amount) and the NOx concentration in the gas immediately after engine exhaust, using the intake air amount as a parameter.
[0115]
According to FIG. 8, it can be seen that the NOx concentration gradually decreases as the ignition timing is retarded. Further, looking at the relationship with the intake air amount that is a parameter, it can be seen that the NOx concentration is larger when the intake air amount is larger, and the NOx concentration is smaller when the air intake amount is vice versa.
[0116]
The following facts are derived from the relationship between the ignition timing, the NOx concentration, and the intake air amount. That is, first, if the intake air amount is increased before or immediately after the start of the retard, as shown by the symbol NAL in FIG. 8, exhaust gas with a high NOx concentration is discharged in a relatively large amount. It will be done. Secondly, even if the intake air amount is increased in a state where the retard angle is not sufficiently advanced, as shown by the symbol NAM in FIG. The exhaust gas having a high concentration is also discharged in a relatively large amount.
[0117]
Thirdly, if the retardation is sufficiently advanced, as shown by the symbol BTL in FIG. 8, the magnitude of the intake amount no longer has a great influence on the NOx concentration. That is, in this range (BTL), it can be seen that even if the intake air amount is increased, the NOx concentration can be kept low (in the above three cases, “large intake air amount” in FIG. 8 respectively). This is an explanation based on the graph.
[0118]
Therefore, in the present embodiment, in step S14 in FIG. 6, the retardation amount is confirmed as a material for enabling the above determination. Then, the increase in the intake air amount is started only when it is determined that the retard amount is equal to or greater than the predetermined value, or in other words, a predetermined period has elapsed from the ignition timing retard start point. (Step S15. Also, refer to FIGS. 7A and 7B for comparison). That is, the EFIECU 170 increases the flow rate of air flowing into the intake manifold 34 by adjusting the throttle opening SC through the control of the throttle motor 42 and the throttle valve 40 after the lapse of the predetermined period. At this time, fuel is pumped from the fuel pump 24 toward the fuel injection valve 22, and the fuel injection valve 22 sends fuel into the combustion chamber 20 in accordance with an increase in the intake air amount or control of the EFIECU 170. To spray.
[0119]
Here, the “predetermined period” between the start time of the ignition retard process and the start time of the intake air amount increase process is based on only FIG. 8, “the period until the retard amount enters the range BTL. Or more generally “a period until the retardation amount exceeds a predetermined retardation threshold value”. Incidentally, in order to make the above determination, more specifically, for example, the following measures can be adopted.
[0120]
First, it is possible to use the current “retard amount” itself more directly. This can be implemented by the EFIECU 170, which controls the ignition timing retarded, storing and referring to the retarded state being performed at any time. The EFIECU 170 can estimate the starting point of the intake air amount increase by confirming the retardation amount.
[0121]
Second, it is possible to use means for detecting the NOx concentration. For example, as shown in FIG. 5, this can be implemented by providing a NOx concentration detection sensor 30N in the exhaust pipe 30. The EFIECU 170 can estimate the starting point of the increase in the intake air amount by monitoring the NOx concentration sent from the NOx concentration detection sensor 30N as needed. That is, as shown in FIG. 8, the NOx concentration gradually decreases with the progress of the retardation, and when the decrease reaches a predetermined level or more, the increase in the intake air amount is started. Become.
[0122]
Incidentally, in order to start the increase in the intake air amount, how much the NOx concentration should be reduced (that is, the preferable decrease in the NOx concentration) depends on the ignition timing at that time, the intake air amount. It can be determined in consideration of various circumstances under specific circumstances. More specifically, referring to FIG. 8, for example, with reference to the NOx concentration (see symbol “P”) when the intake amount is large at “normal ignition timing”, 1/5 to 1 / When a drop of about 10 is confirmed, an increase in the intake air amount can be started.
[0123]
Thirdly, it is possible to use the elapsed time from the start of the ignition timing retardation. This can be implemented by providing a timer (not shown) in the EFIECU 170. That is, for example, after 3 seconds have elapsed from the time at the start point of the ignition timing, the increase of the intake air amount is started. Such a method is possible because the time required for the ignition delay process can be predicted in advance as described above (in the above-mentioned case, “approximately 10 seconds”). This is because the relationship with the concentration can be predicted in advance.
[0124]
In the second or third case described above, the “retard amount” confirmed in step S14 of FIG. 6 can be indirectly estimated through confirmation of the “NOx concentration” or “elapsed time” described above. (A functional relationship exists between them.)
[0125]
According to the above processing, in the present embodiment, the effect that the NOx concentration in the exhaust gas does not increase is obtained although the ignition delay can be started and the catalyst warm-up can be promoted.
[0126]
In this respect, if the ignition timing is retarded and the intake air amount is increased simultaneously as in the prior art, as shown in FIGS. 7 and 8, exhaust gas with a high NOx concentration is discharged. It will be done. That is, according to FIG. 8, since the intake amount increases even though the retardation is hardly progressing, the exhaust gas having the NOx concentration in the range NAL in FIG. 8 is discharged. Further, according to FIG. 7, if the starting points of both the ignition timing retardation and the intake air amount increase are the same (refer to the symbol S and the broken line in FIG. 7B), FIG. ), The exhaust gas having a high NOx concentration is exhausted temporarily or not (reference P in FIGS. 7 and 8 captures the same situation from different viewpoints). Not too much).
[0127]
However, in the present embodiment, as shown by the solid line in FIG. 7B, the intake air amount is increased after the ignition timing is retarded, so in FIG. As indicated by the solid line, the NOx concentration can be kept low.
[0128]
In addition, in this embodiment, the following effects can be obtained in this case. That is, in the hybrid power output apparatus according to the present embodiment, the power generated by motor generators MG1 and MG2 can be transmitted to engine 150. Therefore, according to the present embodiment in which the intake air amount is not increased even though the ignition timing is retarded, the engine speed decreases, which affects the operation of the engine and thus the movement of the vehicle. It might be.
[0129]
However, in the present embodiment, at this time, in order not to affect the engine speed, more specifically, from the motor generators MG1 and MG2 to the engine 150 so as not to decrease the engine speed. Power can be transmitted. In this case, the control unit 190 can control the motor generators MG1 and MG2 so as to meet the above-described meaning based on, for example, the detection result of the rotation speed by the sensor 144.
[0130]
In this regard, the conventional engine 150 (that is, the engine 150 in the case where only the engine 150 and its related elements are present, and the motor generators MG1 and MG2 and their related elements are not present, with reference to FIG. 1). In order to avoid the above-mentioned problems, basically, the process of increasing the intake air amount at the same time when the retard is started, and even if not, It has been done that the amount of retardation that can be executed is limited. Then, in the former case, as described above, the exhaust gas having the NOx concentration in the range NAL in FIG. 8 is exhausted, and in the latter case, the retardation is reached until the range BTL in FIG. 8 is reached. As a result, the exhaust gas having the NOx concentration in the range NAL or NAM is exhausted.
[0131]
However, such an inconvenience does not occur in the present embodiment. In view of the above, it can be said that the power output apparatus and the control method thereof according to the present invention are most effective when applied as a hybrid power control apparatus.
[0132]
In addition, from the above, the application of the present invention to a normal engine is not excluded immediately. As shown in FIG. 8, if the retard amount increases even slightly, the NOx concentration decreases accordingly, and if the retard amount increases to some extent, there is a range in which the NOx concentration drops sharply. (See FIG. 8), it is possible to recognize a corresponding significance in shifting the start point of the retard and the start point of the increase in the intake amount.
[0133]
However, in this case, the retardation amount is limited as described above based on the characteristics shown in FIG. 9, for example. FIG. 9 is a graph showing the relationship between the engine speed and the retard amount with the intake air amount as a parameter.
[0134]
As shown in FIG. 9, when the retard amount increases, the engine speed decreases regardless of the intake air amount. In the above-described embodiment, assist by the motor generators MG1 and MG2 can be made to compensate for the decrease in the rotational speed, but a normal engine is not provided with such a configuration. Therefore, in an ordinary engine, as shown in FIG. 9, the amount that can be retarded in view of the ordinary ignition timing is limited. This is allowed in such a range that the decrease in the rotational speed does not affect the operation of the engine, and hence the operation of the vehicle on which the engine is mounted.
[0135]
In the above description, the explanation is focused on the “NOx concentration”, but the present invention is not limited to this. It is basically possible to perform the control as described above with respect to the “hazardous substance concentration” more broadly. Specific examples of harmful substances include, for example, HC in addition to NOx.
[0136]
(Catalyst warm-up control-end of warm-up control-)
Hereinafter, a method for suitably terminating warm-up of the three-way catalyst device 31 by the control unit 190 and the EFIECU 170 constituting the control means according to the present invention will be described with reference to FIG. FIG. 10 is a flowchart showing the flow of processing of the method for ending the catalyst warm-up and the ignition / intake amount control method executed in association therewith.
[0137]
When the above-described processing of FIG. 6 is completed, the ignition timing is retarded and the intake air amount is increasing for a while. As a result, catalyst warm-up is promoted, but eventually the catalyst is activated and reaches a state where its function can be sufficiently exerted. If such a state is reached, there is no positive reason for maintaining the state of ignition retard and intake amount as described above. Rather, if the state at the time of completion of the process in FIG. 6 is maintained, an adverse effect such as an increase in fuel consumption occurs.
[0138]
Therefore, in FIG. 10, it is first determined whether or not the catalyst is activated (step S21). This determination is nothing but the reverse of the determination in step S11 in FIG. Therefore, this determination can be made based on the detection result of the temperature sensor 31T attached to the three-way catalyst device 31, for example. That is, if the temperature of the catalyst is equal to or higher than a predetermined value, it can be determined that the catalyst has already been activated. Otherwise, it can be determined that the catalyst has not yet been activated. In the former case, the process proceeds to a new process for completing the catalyst warm-up control (from step S21 to step S22). In the latter case, the catalyst warm-up end control is terminated (step S21). To step END).
[0139]
When determining whether or not the catalyst is activated, it is not always necessary to rely on the temperature sensor 31T as in step S11 of FIG. That is, as already described, the current temperature of the catalyst can be estimated from the coolant temperature of the engine 150, the intake air amount, the rotational speed, and the like.
[0140]
Thus, when it is recognized that it is necessary to end the catalyst warm-up, the intake air amount is subsequently decreased (step S22). That is, the EFIECU 170 adjusts the throttle opening SC through the control of the throttle motor 42 and the throttle valve 40, thereby reducing the flow rate of the air flowing into the intake manifold 34.
[0141]
Next, on the premise that the ignition timing that has already been retarded is returned to the normal state (that is, the ignition timing is advanced), it is confirmed how much the intake air amount as a result of the restriction in the above-described step S22 is. (Step S23). The significance of the confirmation of the intake air amount can be explained with reference to FIG. That is, if the ignition timing is advanced when the intake air amount is relatively large, the NOx concentration increases as shown by the solid line in FIG. On the other hand, when the intake air amount is relatively small, the increase in the NOx concentration can be relatively gradual as shown by the broken line in FIG. In step S23 of FIG. 10, in order to avoid a situation in which the NOx concentration suddenly increases, it is confirmed how much the intake air amount is.
[0142]
If the intake air amount is sufficiently low, the process proceeds to a process for advancing the ignition timing (from step S23 to step S24 in FIG. 10). Otherwise, the catalyst warm-up end control is terminated ( Step S23 in FIG. 10 to Step END). Here, when the former is selected, the advance is gradually performed as in the case of retarding the ignition timing (“gradual change” in step S24 in FIG. 10). Indicated.). In this case, the meaning of “gradually” is the same as that already described regarding the retard of the ignition timing. Furthermore, the “advance angle” here has the meaning that the ignition delay is substantially returned to the original state as is apparent from the fact that the ignition delay has already been executed (FIG. 10). Step S24).
[0143]
With the above processing, in the present embodiment, it is possible to avoid a situation in which exhaust gas having a high NOx concentration is discharged even when the catalyst warm-up processing is completed.
[0144]
In the above-described embodiment, the motor generator device includes a plurality of motor generators composed of synchronous motors, but instead of or in addition to at least a part thereof, an induction motor, a vernier motor, a DC motor, a superconducting motor, a step It is also possible to use a motor or the like.
[0145]
In the above-described embodiment, a direct-injection type gasoline engine operated by gasoline is used as the engine 150. In addition, various other types such as a traditional port-injection type gasoline engine, a diesel engine, a turbine engine, and a jet engine are used. An internal combustion engine or an external combustion engine can be used.
[0146]
In addition, the hybrid power output apparatus of the present invention may also be applied to various parallel hybrid type and various serial hybrid type vehicles that are already existing, are currently being developed, or will be developed in the future.
[0147]
The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. The hybrid power output apparatus, the control method for the engine and the hybrid power output apparatus, and the hybrid vehicle are also included in the technical scope of the present invention.
[0148]
【The invention's effect】
As described above, according to the hybrid power output apparatus and the like according to the present invention, NOx or HC in the exhaust gas or in the gas immediately after the engine is discharged although the catalyst warm-up can be realized at an early stage. The amount of harmful substances such as can 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 a collinear diagram for explaining a basic operation of the hybrid vehicle according to the present embodiment.
FIG. 3 is a collinear diagram 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 present 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 process flow of a method for performing catalyst warm-up according to the present embodiment and a method for ignition / intake air amount control executed in accordance therewith.
FIGS. 7A and 7B show the catalyst warm-up process according to the present embodiment through changes in various parameters. FIG. 7A shows a change in the retard amount of the ignition timing according to the time progress, and FIG. FIG. 4C is a characteristic diagram showing the change in the intake air amount and the change in the NOx concentration in the exhaust gas as time progresses.
FIG. 8 is a graph showing the relationship between the ignition timing and the NOx concentration in the gas immediately after engine exhaust, using the intake air amount as a parameter.
FIG. 9 is a graph showing the relationship between the engine speed and the retard amount with the intake air amount as a parameter.
FIG. 10 is a flowchart showing a process flow of a method for ending catalyst warm-up according to the present embodiment and a method for ignition / intake air amount control executed in accordance therewith.
[Explanation of symbols]
20 ... Combustion chamber
26 ... Spark plug
30 ... exhaust pipe
30N ... NOx concentration detection sensor
31. Three-way catalyst device
31T ... Temperature sensor
34 ... Intake manifold
40 ... Throttle valve
42 ... Throttle motor
144: Sensor
150 ... Engine
170 ... EFIECU
190 ... Control unit
MG1, MG2 ... Motor generator

Claims (16)

An engine including a combustion chamber and a spark plug provided in the combustion chamber;
Ignition means for igniting the air-fuel mixture formed in the combustion chamber;
Intake means for sending air into the combustion chamber;
Exhaust purification means for purifying gas exhausted from the combustion chamber with a catalyst;
As a control for warming up the catalyst, after the ignition retarding process is started in which the ignition means delays the ignition timing of the spark plug from the previous state , the concentration of the harmful substance in the gas falls below a predetermined concentration threshold. And a control means for controlling the ignition means and the intake means so as to start an intake air amount increasing process for increasing the amount of air fed into the combustion chamber. When the concentration of the harmful substance in the gas becomes 1/5 to 1/10 as compared to before after the ignition delay process is started,
Power output apparatus according to claim 1, wherein the controller controls the ignition means and the inlet means so as to start the intake air amount increasing process. The power output apparatus according to claim 1 or 2 , further comprising a harmful substance concentration detection means for detecting a concentration of the harmful substance in the gas. The control means, after starting the ignition retardation processing, when the amount of retardation exceeds a predetermined retardation threshold,
The power output apparatus according to any one of claims 1 to 3 , wherein the ignition unit and the intake unit are controlled so as to start the intake air amount increasing process. The control means, after starting the ignition delay processing, when 1-3 seconds have elapsed from the start time,
The power output apparatus according to any one of claims 1 to 4, wherein the controller controls the ignition means and the inlet means so as to start the intake air amount increasing process. The control means includes
Whether to perform the ignition retardation processing, the power output apparatus according to any one of claims 1 to 5, characterized in that determined in accordance with the state of the catalyst. State of the catalyst, the power output apparatus according to claim 6, characterized in that the Suichi based on the temperature of the catalyst. The power output apparatus according to claim 6 or 7 , wherein the state of the catalyst is estimated based on a degree of deterioration of the catalyst. In the motive power output device according to any one of claims 1 to 8 ,
A hybrid-type power output device further comprising a motor generator device capable of generating electric power using at least a part of the output of the engine and outputting a driving force via a drive shaft. The control means includes
After starting the ignition delay processing, at least at a point in time until starting the intake air amount increase processing,
The hybrid power output apparatus according to claim 9 , wherein the number of revolutions of the engine is controlled by the motor generator device. 11. The hybrid power output apparatus according to claim 10 , wherein the control means controls the number of revolutions of the engine by the motor generator apparatus until the ignition delay processing is completely completed. . The control means includes
Ignition advance processing for starting the intake air amount reduction processing for returning the amount of air fed into the combustion chamber from the increased state to the previous state, and then causing the ignition timing in the spark plug to advance from the retarded state the power output apparatus according to any one of claims 1 to 8, wherein the controller controls the ignition means and the inlet means to start. The control means includes
After the start of the intake air amount reduction process, when the amount of air falls below a predetermined threshold,
The power output apparatus according to claim 12 , wherein the ignition means and the intake means are controlled to start the ignition advance processing. The hybrid power output device according to any one of claims 9 to 11 ,
A vehicle body on which the power output device is mounted;
A hybrid vehicle comprising: a wheel attached to the vehicle main body and driven by the driving force output via the drive shaft. A control method for controlling an engine including a combustion chamber and a spark plug provided in the combustion chamber,
A first step of delaying the ignition timing in the spark plug from a previous state;
A second step of increasing the amount of air fed into the combustion chamber ;
A third step of returning the amount of air fed into the combustion chamber to a previous state;
A fourth step of advancing the timing of ignition in the spark plug from a retarded state ,
Start time of the second step, rather slow than the starting point of the first step,
The engine control method , wherein the fourth step is performed after the start of the third step . The engine control method according to claim 15 , wherein
The engine is connected to a motor generator device capable of generating power using at least a part of its output and capable of outputting a driving force via a drive shaft,
A method for controlling a hybrid type power output apparatus, comprising the step of controlling the number of revolutions of the engine by the motor generator device at least at one point of the first step.

Images