JP2009113665A - Vehicle control apparatus and method - Google Patents

Abstract

In a vehicle such as an automobile, heat deterioration of components related to exhaust gas is prevented, and deterioration of vehicle drivability and fuel consumption are avoided.
A vehicle control device (300) includes an internal combustion engine (21), fuel supply means (27) for supplying fuel to the internal combustion engine, and at least a part of exhaust gas discharged from the internal combustion engine. An exhaust gas recirculation means (60) capable of returning to the engine, a speed change mode capable of continuously changing the speed ratio at the output of the internal combustion engine, and a fixed mode where the speed ratio cannot be changed continuously can be switched between each other. It is a control apparatus of a vehicle (1) provided with a transmission (10). The vehicle control device controls the transmission to switch to the fixed mode on the condition that the detected temperature is higher than the temperature threshold, and the temperature detection means (33) for detecting the temperature related to the exhaust gas, Control means (31) for controlling the exhaust gas recirculation means so as to recirculate at least part of the exhaust gas to the internal combustion engine.
[Selection] Figure 1

Description

  The present invention relates to a vehicle control apparatus and method for controlling a transmission having a plurality of modes, such as a continuously variable transmission mode and a fixed mode, including, for example, a motor generator (MG), a continuously variable transmission (CVT), and the like.

  With this type of device, it is possible to avoid problems caused by switching the mode of a transmission having a plurality of modes. For example, Patent Document 1 describes a hybrid vehicle drive apparatus in which a power source, an output member, and a first motor / generator are connected to a power distribution mechanism including a plurality of sets of differential mechanisms. Here, in particular, in a state in which the first motor / generator continuously changes the rotation speed ratio between the power source and the output member by inputting and outputting torque (that is, continuously variable transmission state), There is described a technique for reducing power loss in a continuously variable transmission state by configuring so that a plurality of differential mechanisms do not contribute to torque transmission between one motor / generator and an output member.

  Further, Patent Document 2 includes a first transmission mode in which power of an internal combustion engine is transmitted, a transmission having an input element and an output element, and the speed ratio between the internal combustion engine and the output element cannot be changed, A vehicle control device capable of selectively switching between a second shift mode in which the ratio can be changed is described. Here, in particular, by selecting either the first speed change mode or the second speed change mode based on the state of vibration or booming noise caused by fluctuations in the rotational speed of the internal combustion engine, the drive train associated with the change of the speed change mode is selected. A technique for suppressing vibration and noise is described.

  In general, when the catalyst is in a predetermined high temperature state, the throttle valve opening is controlled in the closing direction, the gear ratio of the automatic transmission is reduced, or the amount of fuel supplied to the internal combustion engine is increased. Therefore, a technique for preventing an increase in harmful exhaust gas and a deterioration in fuel efficiency while preventing deterioration of the catalyst due to heat has been proposed (see Patent Document 3). Further, the air-fuel ratio is recirculated by performing EGR (Exhaust Gas Recirculation) gas prior to the timing of switching the air-fuel ratio from the rich air-fuel ratio to the lean air-fuel ratio, or prior to the timing of switching from the lean air-fuel ratio to the rich air-fuel ratio. There has been proposed a technique for suppressing the temperature rise of exhaust gas accompanying the switching of the gas (see Patent Document 4).

JP 2005-24071 A JP 2004-345527 A JP-A-8-165941 Japanese Patent Laid-Open No. 5-187327

  However, according to the techniques described in Patent Documents 1 and 2, the temperature related to the exhaust gas is not considered. As described in Patent Document 3, there is a technical problem that the drivability of the vehicle may deteriorate even if the opening degree of the throttle valve is controlled in the closing direction and the gear ratio is reduced. is there. Alternatively, the fuel supplied to the internal combustion engine is increased as described in Patent Document 3, or the EGR gas is recirculated before the fuel is increased as described in Patent Document 4. However, there is a technical problem that fuel consumption may deteriorate.

  The present invention has been made in view of the above problems, for example, and controls a vehicle that can prevent thermal deterioration of components related to exhaust gas and avoid deterioration of vehicle drivability and fuel consumption. It is an object to provide an apparatus and a method.

  In order to solve the above-described problems, a vehicle control apparatus according to the present invention includes an internal combustion engine, fuel supply means for supplying fuel to the internal combustion engine, and at least part of exhaust gas discharged from the internal combustion engine. Exhaust gas recirculation means capable of returning to the engine, a transmission capable of continuously changing the speed ratio at the output of the internal combustion engine, and a transmission capable of switching between the fixed mode where the speed ratio cannot be changed continuously A temperature detecting means for detecting a temperature related to the exhaust gas, and the transmission so as to switch to the fixed mode on condition that the detected temperature is higher than a temperature threshold. And control means for controlling the exhaust gas recirculation means so as to recirculate at least part of the exhaust gas to the internal combustion engine.

  According to the vehicle control apparatus of the present invention, the vehicle control apparatus includes, for example, an internal combustion engine that is an engine, fuel supply means that supplies fuel such as gasoline or alcohol mixed fuel to the internal combustion engine, and exhaust from the internal combustion engine. The exhaust gas recirculation means that can recirculate at least part of the exhaust gas to the internal combustion engine, for example, EGR, and the speed change mode and the speed change ratio that can continuously change the speed ratio at the output of the internal combustion engine. It is mounted on a vehicle such as an automobile including a transmission capable of switching between impossible fixed modes.

  For example, the fuel supply means that is a fuel injection valve may be provided in an intake passage connected to the internal combustion engine, or may be provided in a cylinder of the internal combustion engine (so-called direct injection type internal combustion engine). May be).

  Here, “at least a part of the exhaust gas can be recirculated to the internal combustion engine” according to the present invention means that at least a part of the exhaust gas is taken out from the exhaust passage connected to the internal combustion engine, and This means that it is possible to return at least a part of the air to the intake passage connected to the internal combustion engine and allow the internal combustion engine to take air again.

  The exhaust gas recirculation means is typically provided with a control valve that controls the amount of exhaust gas that is returned to the intake passage, and cooling means that cools the exhaust gas that is returned. The exhaust gas recirculation means opens the control valve and returns at least a part of the exhaust gas in the exhaust passage to the intake passage using the negative pressure in the intake passage. For this reason, the amount of exhaust gas that is returned varies depending on the opening and opening time of the control valve and the negative pressure in the intake passage. The exhaust gas returned to the intake passage is cooled by the cooling means.

  The transmission has an input shaft connected to the internal combustion engine and an output shaft connected to the axle. The transmission continuously changes the speed ratio and speed ratio that can continuously change the speed ratio (that is, the speed ratio) between the input speed that is the speed of the input shaft and the output speed that is the speed of the output shaft. It is possible to switch between fixed modes that cannot be changed. The “fixed mode” according to the present invention typically means a mode in which the gear ratio is smaller than that in the gear shift mode on the equal power line, that is, the gear ratio is fixed on the high speed side. . Therefore, in the fixed mode, the load on the internal combustion engine is reduced and the rotational speed is increased as compared with the shift mode.

  The temperature detecting means detects the temperature related to the exhaust gas discharged from the internal combustion engine. Here, the “temperature related to the exhaust gas” according to the present invention is not limited to the temperature of the exhaust gas itself, but, for example, the temperature of the material constituting the exhaust passage, the temperature of the catalyst provided in the exhaust passage, etc. It may mean the temperature of a part where heat transfer occurs as the gas passes through.

  Further, “detecting the temperature related to the exhaust gas” may mean, for example, directly detecting the temperature by a temperature sensor or the like. For example, the amount of intake air sucked into the internal combustion engine or the internal combustion engine This may mean indirectly detecting, calculating, or estimating the temperature based on some physical quantity or parameter such as the number of rotations.

  The control means controls the transmission to switch the transmission mode to the fixed mode on the condition that the detected temperature is higher than the temperature threshold, and recirculates at least a part of the exhaust gas to the internal combustion engine. Control the exhaust gas recirculation means.

  Here, the “temperature threshold” according to the present invention is a value that determines whether or not to switch the transmission mode to the fixed mode, or whether or not to maintain the fixed mode. This is a value set as a variable value according to the parameter. This temperature threshold is set, for example, as a temperature at which the thermal strain generated in the material exceeds an allowable range, a temperature at which the performance of the material deteriorates or becomes remarkable, or a temperature lower than the temperature by a predetermined value.

  Such a temperature threshold is obtained by empirically or experimentally or by simulation to determine the relationship between temperature and thermal strain generated in the material, or to determine the relationship between temperature and the degree of performance degradation of the material. What is necessary is just to set based on established relationship. A plurality of temperature thresholds corresponding to a plurality of exhaust gases, such as the temperature of the material constituting the exhaust passage and the temperature of the catalyst, may be set. In this case, on the condition that at least one of the temperatures related to the plurality of exhaust gases is higher than the temperature threshold value, the control means may control the transmission so as to switch the transmission mode to the fixed mode. .

  According to the inventor's research, when the transmission mode in the vehicle is the shift mode and the detected exhaust gas temperature is higher than the temperature threshold, the temperature of the exhaust gas is decreased. In addition, even if at least part of the exhaust gas is recirculated to the internal combustion engine without switching the transmission mode (that is, while maintaining the transmission mode), there is a possibility that the effect cannot be obtained sufficiently. Specifically, for example, if the load applied to the internal combustion engine is high, the difference between the pressure of the intake passage and the pressure of the exhaust passage is small, or the pressure of the intake passage is larger than the pressure of the exhaust passage, It is difficult to recirculate exhaust gas simply by opening the valve.

  In addition, even if the amount of fuel supplied to the internal combustion engine is increased (that is, even if the air-fuel ratio is made rich), the fuel efficiency may deteriorate, and the throttle valve opening is controlled in the closing direction and the gear ratio is changed. It has been found that the drivability of the vehicle may be deteriorated even if the value is reduced.

  However, in the present invention, when the detected temperature becomes higher than the temperature threshold, the transmission is controlled by the control means so as to switch the transmission mode to the fixed mode, and at least a part of the exhaust gas is supplied to the internal combustion engine. The exhaust gas recirculation means is controlled so as to recirculate. When the transmission mode is switched to the fixed mode, typically, the load on the internal combustion engine is reduced and the rotational speed is increased as compared with the transmission mode, so that the negative pressure in the intake passage increases. At this time, when the exhaust gas recirculation means is controlled by the control means so as to recirculate at least part of the exhaust gas to the internal combustion engine, that is, when the control valve is opened, the negative pressure in the intake passage increases. Therefore, the amount of exhaust gas returned to the intake passage increases.

  In other words, when the detected temperature is higher than the temperature threshold, switching the transmission mode to the fixed mode and opening the control valve automatically increases the negative pressure in the intake passage, which is efficient. In addition, at least part of the exhaust gas can be recirculated to the internal combustion engine. Thereby, the temperature of the exhaust gas discharged | emitted from an internal combustion engine can be reduced.

  In addition, the predetermined or optimal ignition timing in the fixed mode is earlier than the predetermined or optimal ignition timing in the shift mode. In other words, by switching the transmission mode from the shift mode to the fixed mode, the ignition timing is relatively advanced (that is, the ignition timing is advanced). Therefore, the temperature of the exhaust gas discharged from the internal combustion engine can also be lowered by advancing the ignition timing.

  Note that the ignition timing is relatively advanced by switching the transmission mode to the fixed mode, but a predetermined or optimal ignition timing is intentionally advanced in an operating state of a certain internal combustion engine. Therefore, the possibility of damaging the internal combustion engine such as, for example, knocking can be eliminated or reduced.

  Furthermore, as described above, the transmission mode is typically switched between the shift mode and the fixed mode on the equal power line, so that the drivability of the vehicle deteriorates due to the mode switching. There is nothing. Further, since the amount of fuel supplied to the internal combustion engine is not increased, that is, typically, the fuel is supplied so that the stoichiometric air-fuel ratio is obtained, it is possible to avoid deterioration of the fuel efficiency of the vehicle.

As a result, according to the vehicle control apparatus of the present invention, it is possible to prevent thermal deterioration of components related to exhaust gas and to avoid deterioration of vehicle drivability and fuel consumption. In one aspect of the apparatus, the control unit includes a determination unit that determines whether or not the detected temperature is higher than the temperature threshold, and switches to the fixed mode when it is determined that the detected temperature is higher than the temperature threshold. Controlling the transmission as described above and controlling the exhaust gas recirculation means to recirculate at least a part of the exhaust gas to the internal combustion engine. The transmission is controlled so as not to be switched to.

  According to this aspect, it can be determined relatively easily whether or not the detected temperature is higher than the temperature threshold.

  When it is determined that the detected temperature is higher than the temperature threshold, the control unit controls the transmission to switch the transmission mode to the fixed mode and recirculates at least a part of the exhaust gas to the internal combustion engine. The exhaust gas recirculation means is controlled. On the other hand, if it is determined that the detected temperature is lower than the temperature threshold value, the speed change is typically performed on condition that the control means does not satisfy other switching conditions for controlling the transmission to switch to the fixed mode. The transmission is controlled so that the mode of the machine does not switch to the fixed mode. That is, “controlling the transmission so as not to switch to the fixed mode” according to the present invention means that the transmission mode is fixed depending on the condition that “the temperature of the detected exhaust gas is higher than the temperature threshold”. This means that the transmission is controlled so as not to switch to the mode. Therefore, even if it is determined that the temperature is lower than the temperature threshold value, the transmission is typically controlled so that at least the transmission mode is switched to the fixed mode when other switching conditions are satisfied. The “other switching condition” is, for example, vehicle vibration or a booming noise or a fuel consumption rate.

  The control means is not limited to the case where it is determined that the detected temperature is higher than the temperature threshold value, and at least a part of the exhaust gas is recirculated to the internal combustion engine periodically, irregularly, or continuously. Thus, the exhaust gas recirculation means may be controlled.

  In another aspect of the vehicle control device of the present invention, the speed ratio in the fixed mode is smaller than the speed ratio in the speed change mode.

  According to this aspect, on the equal power line, the speed ratio in the fixed mode is smaller than the speed ratio in the speed change mode. This makes it relatively easy to increase the negative pressure in the intake passage, which is very advantageous in practice.

  In another aspect of the vehicle control apparatus of the present invention, the vehicle control device further includes a rotation speed detection means for detecting the rotation speed of the internal combustion engine, and an intake air detection means for detecting an intake air amount sucked into the internal combustion engine, The temperature detection means detects the temperature based on the detected rotation speed and the detected intake air amount.

  According to this aspect, for example, the rotation speed detection means that is a rotation speed sensor detects the rotation speed of the internal combustion engine. The intake air detection means detects the amount of intake air taken into the internal combustion engine. The intake air amount may be detected directly by, for example, an air flow meter or the like, or based on the pressure in the intake passage connected to the internal combustion engine and the rotational speed detected by the rotational speed detection means. You may detect indirectly.

  Based on the detected number of revolutions and the detected amount of intake air, the temperature detecting means, for example, uses an arithmetic expression that uses the detected number of revolutions and the detected amount of intake air as a coefficient or a variable. Calculate the temperature. Or the temperature which concerns on exhaust gas is estimated or specified using the map which shows the relationship between the detected rotation speed, the detected amount of intake air, and the temperature which concerns on exhaust gas.

  Note that such a map shows the exhaust passage temperature, catalyst temperature, etc. when the rotational speed of the internal combustion engine and the amount of intake air taken into the internal combustion engine are variously changed, for example, experimentally or by simulation. The temperature relating to the exhaust gas may be detected, measured or calculated, and the relationship between the detected temperature, rotation speed, and intake air amount may be specified.

  In another aspect of the vehicle control apparatus of the present invention, the control means supplies the internal combustion engine with the condition that the detected temperature is higher than a temperature threshold when the transmission is in the fixed mode. The fuel supply means is controlled so that the amount of the supplied fuel increases.

  According to this aspect, when the transmission mode is the fixed mode and the detected exhaust gas temperature is higher than the temperature threshold, or the detected exhaust gas temperature is the temperature. When the temperature relating to the newly detected exhaust gas becomes higher than the temperature threshold after the transmission mode is switched to the fixed mode, the control means supplies fuel to be supplied to the internal combustion engine. The fuel supply means is controlled so that the amount increases, that is, the air-fuel ratio becomes rich.

  As a result, the temperature of the exhaust gas can be lowered, and at least thermal degradation of components related to the exhaust gas can be prevented.

  In another aspect of the vehicle control apparatus of the present invention, the control means is configured to set the internal combustion engine on the condition that the detected temperature is higher than a temperature threshold when the transmission cannot be controlled to switch to the fixed mode. The fuel supply means is controlled so that the supply amount of the fuel supplied to the engine increases.

  According to this aspect, it is possible to prevent at least thermal degradation of components related to exhaust gas.

  Note that “when the transmission cannot be controlled to switch to the fixed mode” means, for example, by switching the mode of the transmission to the fixed mode, the vibration of the power transmission system (for example, the power train) in the vehicle or the room A material that constitutes a power transmission system, etc., when the booming sound is in a driving state that causes a feeling of discomfort or anxiety to the operator, etc., or the frequency of vibration generated in the power transmission system becomes a resonance band For example, a strain exceeding the allowable range occurs.

  In such a case where “the transmission cannot be controlled to switch to the fixed mode”, for example, vibration generated in the power transmission system or the like is directly detected by a vibration sensor or the like, or the rotational speed of the internal combustion engine, Based on one or more physical quantities or parameters such as temperature, torque or load, indirectly detect vibrations etc. generated in the power transmission system etc., and whether the detected vibrations etc. are larger than a predetermined value, or It is determined whether or not the detected vibration or the like is within a predetermined range, and when it is determined that the detected vibration or the like is greater than a predetermined value, or the detected vibration or the like is determined to be within the predetermined range. May be detected as “when the transmission cannot be controlled to switch to the fixed mode”.

  In any case, when the transmission cannot be controlled to switch to the fixed mode (in other words, when conditions for prohibiting switching to the fixed mode are met), the control means is supplied to the internal combustion engine as described above. The fuel supply means is controlled so that the fuel supply amount increases. In particular, whether or not this is the case is constantly monitored, and in such a case, for example, a “fixed mode prohibition flag” is set to indicate that the conditions for prohibiting the fixed mode are met. Alternatively, the control means may control the fuel supply means so that the amount of fuel supplied to the internal combustion engine increases as described above when the fixed mode prohibition flag is set.

  Note that either the determination as to whether or not the transmission cannot be controlled to switch to the fixed mode and the determination as to whether or not the detected temperature is higher than the temperature threshold may be performed first or in parallel. (Ie, simultaneously).

  In addition, when indirectly detecting vibration or the like, for example, vibration or the like may be detected according to a predetermined arithmetic expression using one or more physical quantities or parameters as variables or coefficients, A map indicating a relationship with a physical quantity or a parameter may be stored in advance in storage means such as a flash memory, and vibration or the like may be detected or specified from the stored map. Such a map is obtained by detecting, measuring or calculating one or a plurality of physical quantities or parameters including vibrations or the like in an arbitrary driving state of the vehicle, for example, by an experiment, and the one or a plurality of physical quantities thus detected. Alternatively, the relationship between the vibration and the one or more physical quantities or parameters may be specified from the parameters.

  In order to solve the above problems, the vehicle control means of the present invention includes an internal combustion engine, fuel supply means for supplying fuel to the internal combustion engine, and at least part of exhaust gas discharged from the internal combustion engine. Exhaust gas recirculation means capable of returning to the engine, a transmission capable of continuously changing the speed ratio at the output of the internal combustion engine, and a transmission capable of switching between the fixed mode where the speed ratio cannot be changed continuously A temperature detection step of detecting a temperature related to the exhaust gas, and the transmission so as to switch to the fixed mode on condition that the detected temperature is higher than a temperature threshold. And a control step of controlling the exhaust gas recirculation means so as to recirculate at least part of the exhaust gas to the internal combustion engine.

  According to the vehicle control method of the present invention, in the same manner as the vehicle control apparatus of the present invention described above, thermal deterioration of components related to exhaust gas is prevented, and deterioration of vehicle drivability and fuel consumption are avoided. be able to.

  In the vehicle control method of the present invention, it is possible to adopt various aspects similar to the various aspects of the vehicle control apparatus of the present invention described above.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, an embodiment according to a vehicle equipped with a control device of the present invention will be described with reference to FIGS. 1 to 3.

  First, the configuration of the vehicle according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram of a vehicle according to the present embodiment. Here, the vehicle according to the present embodiment is an FF (Front-engine, Front-wheel drive) type vehicle. The vehicle on which the control device of the present invention is mounted is not limited to the FF type vehicle, and for example, the FR (Front-engine, Rear-wheel drive) type or the RR (Rear-engine, Rear-- Vehicles of various types such as a “wheel drive” type may be used.

  In FIG. 1, a vehicle 1 includes a transmission 10, an internal combustion engine 21, and an ECU 30. The internal combustion engine 21 includes an air cleaner 24, an air flow meter 25, a throttle valve 26, a fuel injection valve 27 that supplies fuel stored in the fuel container 26 to the internal combustion engine 21, and the like, and An exhaust passage 23 in which an air-fuel ratio sensor 42, an oxygen sensor 43, and catalysts 51 and 52 are provided is connected. Further, the internal combustion engine 21 is provided with a rotation speed sensor 31 that detects the rotation speed of the internal combustion engine, and an ignition plug (not shown) that ignites the fuel supplied by the fuel injection valve 27.

  Here, the “air flow meter 25”, “fuel injection valve 27”, and “rotational speed sensor 41” according to the present embodiment are respectively referred to as “intake air detection means”, “fuel supply means”, and “rotation speed” according to the present invention. It is an example of “number detection means”.

  The intake passage 22 and the exhaust passage 23 are connected via an EGR device 60 as an example of “exhaust gas recirculation means” according to the present invention, which can recirculate at least part of the exhaust gas in the exhaust passage 23 to the internal combustion engine 21. It is connected.

  The EGR device 60 is provided with an EGR cooler 61 that cools the exhaust gas returned to the intake passage 22 and an EGR control valve 62 that controls the amount of exhaust gas returned. When the EGR control valve 62 is opened, a part of the exhaust gas in the exhaust passage 23 passes through the EGR cooler 61 and is returned to the intake passage 22 due to the negative pressure in the intake passage 22. When the exhaust gas passes through the EGR cooler 61, its temperature is lowered.

  The ECU 30 configured to perform various electronic controls in the vehicle 1 includes a control unit 31, a determination unit 32, a temperature estimation unit 33, a storage unit 34, and an input / output unit 35. In the present embodiment, a part of the ECU 30 for various electronic controls is used as a part of the control device 300. Here, the “control unit 31”, “determination unit 32”, and “temperature estimation unit 33” according to the present embodiment are respectively the “control unit”, “determination unit”, and “temperature detection unit” according to the present invention. It is an example.

  The transmission 10 includes a power distribution mechanism 101, a motor / generator (MG) 102, a generator 103, and a speed reducer 104.

  The power distribution mechanism 101 includes a planetary gear mechanism. A planetary carrier rotation shaft 101 a of the planetary gear mechanism is connected to the internal combustion engine 21, and an outer ring gear rotation shaft 101 b is connected to the motor / generator 102. The sun gear rotating shaft 101 c is connected to the generator 103. The planetary carrier rotation shaft 101a and the sun gear rotation shaft 101c are arranged on the same axis. For convenience of explanation, in FIG. 1, the rotation shafts 101a and 101c are arranged on different axes.

  The generator 103 generates electric power by being driven by the rotating shaft 101c, and charges the storage battery 12 or drives the motor / generator 102 via a PCU (Power Control Unit) 11 including an inverter and the like. To do.

  The motor / generator 102 is supplied with electric power from the generator 103 or the storage battery 12 or the generator 103 and the storage battery 12 and is driven. On the other hand, when the vehicle 1 decelerates or brakes, it acts as a regenerative brake to charge the storage battery 12.

  During operation, the internal combustion engine 21 drives the rotating shaft 101 a to transmit power to the power distribution mechanism 101. The planet carrier in the power distribution mechanism 101 transmits a part of the transmitted power to the internal sun gear via the planetary gear, and transmits the other part of the transmitted power to the external outer gear.

  The power transmitted to the sun gear drives the generator 103 through the rotating shaft 101c. On the other hand, the power transmitted to the outer ring gear drives the wheel 14 via the rotary shaft 101b, the speed reducer 104, and the drive shaft 13. Note that the rotational speed of the motor / generator 102 matches the rotational speed of the rotating shaft 101b.

  Therefore, by controlling the rotation speed and rotation direction of the rotation shaft 101c (that is, the rotation speed and rotation direction of the generator 102), the rotation speed ratio between the rotation shaft 101a and the rotation shaft 101b (that is, the rotation shaft 101a The speed ratio between the rotation speed and the rotation speed of the rotation shaft 101b) is controlled continuously (that is, steplessly) (hereinafter also referred to as “shift mode”).

  The generator 103 includes a mechanism for fixing the rotating shaft 101c. When the rotating shaft 101c is fixed by the mechanism (that is, the sun gear is fixed), the generator 103 is interposed between the rotating shaft 101a and the rotating shaft 101b. The rotation speed ratio is constant (hereinafter also referred to as “fixed mode”).

  Here, the operation of the internal combustion engine 21 will be described with reference to FIG. FIG. 2 is a characteristic diagram showing an example of an operation line showing the operation of the internal combustion engine 21 according to the present embodiment. In FIG. 2 (a), a solid line a, a broken line b, and an alternate long and short dash line c are a power operation line, a fuel consumption operation line in the shift mode, and a fuel consumption operation line in the fixed mode, respectively. p3 is an equal power line.

  The “power operation line a” indicates the operation of the internal combustion engine 21 when power is required such as when the vehicle 1 is suddenly accelerated. In this case, the transmission 10 is in the speed change mode, and the vehicle 1 typically travels by the driving force of the internal combustion engine 21 and the driving force of the motor / generator 102 supplied with power from the generator 103 and the storage battery 12. To do.

  Further, the “fuel consumption operation line b in the speed change mode” indicates the operation of the internal combustion engine 21 at the normal time. In this case, the vehicle 1 typically travels by the driving force of the internal combustion engine 21 and the driving force of the motor / generator 102 supplied with electric power from the generator 103. “Fuel consumption operation line c in the fixed mode” indicates the operation of the internal combustion engine 21 when the transmission 10 is in the fixed mode. In this case, the vehicle 1 typically travels by the driving force of the internal combustion engine 21 and the driving force of the motor / generator 102 supplied with electric power from the storage battery 12.

  For example, when the internal combustion engine 21 is operating in the state of point A in FIG. 2A, when the mode of the transmission 10 is switched from the shift mode to the fixed mode, the internal combustion engine 21 is fixed to the equal power line p2. It operates in the state of the point B that is the intersection with the fuel consumption operation line c in the mode. As a result, the engine shifts to the high speed side, the rotation speed of the internal combustion engine 21 increases (that is, the rotation speed increases), and the torque decreases (that is, the load is reduced).

  Next, the fuel consumption rate will be described with reference to FIG. FIG. 2B is a characteristic diagram obtained by adding equal fuel consumption rate curves f1 to f5 of the internal combustion engine 21 to FIG. In addition, the fuel consumption rate of the equal fuel consumption rate curve f1 is good, and the fuel consumption rate becomes worse as the distance from the constant fuel consumption rate curve f1 increases.

  As can be seen from FIG. 2 (b), the fuel consumption rate of the internal combustion engine 21 itself deteriorates as the operating state of the internal combustion engine 21 shifts from point A to point B, but the power transmission efficiency is increased by setting the fixed mode. (That is, power is not transmitted to the generator 103), the fuel efficiency of the vehicle 1 as a whole is improved. An internal combustion engine in which the state of point C that is the intersection of the fuel consumption operation line b in the shift mode and the fuel consumption operation line c in the fixed mode is the best in improving the fuel consumption rate by switching the mode of the transmission 10 to the fixed mode. 21 operating states.

  When the fuel efficiency of the vehicle 1 as a whole deteriorates even when power transmission efficiency is taken into account (for example, below the dotted line th in FIG. 2B), the control unit 31 typically includes a transmission. The transmission 10 is controlled so as not to switch the 10 mode to the fixed mode.

  Returning to FIG. 1 again, the temperature estimation unit 33 detects the temperature related to the exhaust gas discharged from the internal combustion engine 21. Specifically, the temperature estimation unit 33 is typically stored in the storage unit 34 based on the intake air amount detected by the air flow meter 25 and the rotational speed of the internal combustion engine 21 detected by the rotational speed sensor 41. The temperature of the exhaust passage 23 material, the temperatures of the catalysts 51 and 52, the temperature of an exhaust valve seat (not shown), etc. are estimated from the temperature map showing the relationship between the intake air amount, the rotational speed and the temperature related to the exhaust gas. .

  The storage unit 34 typically stores a plurality of temperature maps corresponding to the exhaust passage 23 material, the catalysts 51 and 52, the exhaust valve seat, and the like.

  The determination unit 32 determines whether the estimated temperature is higher than the temperature threshold. The temperature threshold is typically set for each of the exhaust passage 23 material, the catalysts 51 and 52, the exhaust valve seat, and the like. For example, the temperature threshold for the exhaust passage 23 material and the catalysts 51 and 52 is Each is 900 degrees Celsius, and the temperature threshold for the exhaust valve seat is 850 degrees Celsius.

  The control unit 31 determines that the mode of the transmission 10 is the shift mode and at least one of the temperatures of the exhaust passage 23 material, the catalysts 51 and 52, the exhaust valve seat, and the like is higher than the corresponding temperature threshold. In this case, the EGR device controls the transmission 10 so as to switch the mode of the transmission 10 to the fixed mode and opens the EGR control valve 62 in order to return a part of the exhaust gas to the internal combustion engine 21. 60 is controlled. Then, as described above, since the load on the internal combustion engine 21 is reduced and the rotational speed is increased, the negative pressure in the intake passage 22 is increased, and the amount of exhaust gas returned to the intake passage 22 is increased. Thereby, the temperature of the exhaust gas can be lowered, and the temperatures of the exhaust passage 23 material, the catalysts 51 and 52, the exhaust valve seat, and the like can be lowered.

  In addition, when the mode of the transmission 10 is switched from the shift mode to the fixed mode, the timing at which the control unit 31 controls the spark plug so as to ignite the fuel supplied to the internal combustion engine 21 in the shift mode (that is, The ignition timing is earlier than the ignition timing. In other words, the predetermined or optimal ignition timing in the fixed mode is earlier than the predetermined or optimal ignition timing in the shift mode.

  Therefore, if it is determined that the temperature is higher than the temperature threshold value, the control unit 31 controls the transmission 10 so as to switch the mode of the transmission 10 to the fixed mode. The temperature can be lowered. In addition, although the ignition timing is relatively advanced by switching the mode of the transmission 10 to the fixed mode, the predetermined ignition timing or the optimal ignition timing is intentionally advanced in an operating state of a certain internal combustion engine 21. Therefore, the possibility of damaging the internal combustion engine 21 such as occurrence of knocking can be eliminated or reduced.

  Furthermore, since the mode of the transmission 10 is switched between the shift mode and the fixed mode on the equal power line, the drivability of the vehicle 1 is not deteriorated by switching the mode. Further, since the internal combustion engine 21 is typically operated while maintaining the theoretical air-fuel ratio, it is possible to avoid the deterioration of the fuel consumption of the entire vehicle 1.

  On the other hand, if the determination unit 32 determines that all of the temperatures of the exhaust passage 23 material, the catalysts 51 and 52, the exhaust valve seat, and the like are lower than the corresponding temperature threshold, the control unit 31 switches to the fixed mode. On the condition that other switching conditions for controlling the transmission 10 are not satisfied, the control unit 31 typically controls the transmission 10 to maintain the transmission mode.

  The control unit 31 is not limited to the case where it is determined that the estimated temperature is higher than the temperature threshold value, and a part of the exhaust gas is returned to the internal combustion engine 21 periodically, irregularly, or continuously. The EGR device 60 may be controlled to do so.

  Here, an example of another switching condition for controlling the transmission 10 so that the control unit 31 switches the mode of the transmission 10 to the fixed mode will be described.

  For example, the control unit 31 detects the rotational speed of the internal combustion engine 21 with the rotational speed sensor 41, or from the signal indicating the vehicle speed of the vehicle 1 from a vehicle speed sensor (not shown) and the gear ratio of the transmission 10. The speed of the transmission 10 is switched to the fixed mode on the condition that the detected or determined speed is greater than a predetermined threshold value. This is because when the rotational speed of the internal combustion engine 21 is less than or equal to a predetermined threshold value, the combustion state of the internal combustion engine 21 becomes unstable, so the fluctuation of the rotational speed increases, and the power distribution mechanism 101, the speed reducer 104, and the like This is for reducing or avoiding the possibility of the vibration of the transmission system and the interior noise of the vehicle 1.

  Further, the control unit 31 compares the fuel efficiency of the entire vehicle 1 in the shift mode with the fuel efficiency of the entire vehicle 1 in the fixed mode on the equal power line, and the fuel efficiency of the entire vehicle 1 in the fixed mode is good. As a condition, the mode of the transmission 10 is switched to the fixed mode. The fuel consumption rate of the entire vehicle 1 is calculated based on, for example, the driving force and torque to be generated based on the vehicle speed and the accelerator opening, and the internal combustion engine 21 and the motor / generator 102 are calculated based on the calculated torque. The shared torque may be calculated and obtained based on the calculated shared torque of the motor / generator 102.

  Further, when selecting the fixed mode, the control unit 31 switches the mode of the transmission 10 to the fixed mode on condition that the driving force required by the vehicle 1 can be output. In addition, what is necessary is just to obtain | require the driving force which the vehicle 1 requires based on a vehicle speed and an accelerator opening, for example.

  The control unit 31 determines the mode of the transmission 10 when at least one of the switching conditions is satisfied, including the case where the determination unit 32 determines that the temperature estimated by the temperature estimation unit 33 is higher than the temperature threshold. The transmission 10 is controlled to switch to the fixed mode.

  However, even when it is determined that the estimated temperature is higher than the temperature threshold, by controlling the transmission 10 so as to switch to the fixed mode, for example, vibration of the power transmission system and indoor noise in the vehicle 1 Or the frequency of the vibration generated in the power transmission system becomes a resonance band, and distortion exceeding the allowable range occurs in the material constituting the power transmission system. In the case where the driver feels uncomfortable or uneasy (hereinafter, also referred to as “fixed mode prohibition condition”), the control unit 31 controls the transmission 10 so as not to switch to the fixed mode. .

  Specifically, for example, it is generated in the power transmission system detected, calculated or estimated by the determination unit 32 based on the rotational speed of the internal combustion engine 21 detected by the rotational speed sensor 41, the gear ratio of the transmission 10, or the like. When it is determined that the vibration or the like is greater than the predetermined value, or when it is determined that the vibration is within the predetermined range, the control unit 31 determines that the fixed mode prohibition condition is satisfied, so that the transmission 10 does not switch to the fixed mode. To control.

  Or, regardless of whether or not the estimated temperature is higher than the temperature threshold value, vibration or the like generated in the power transmission system or the like is always detected, calculated or estimated, and vibration or the like generated in the detected power transmission system or the like is detected. When it is determined that the value is larger than the predetermined value, or when it is determined that the value is within the predetermined range, the “fixed mode prohibition flag” is set. Then, when it is determined that the estimated temperature is higher than the temperature threshold, the control unit 31 controls the transmission 10 so as not to switch to the fixed mode on condition that the fixed mode prohibition flag is set.

  In this case, the control unit 31 controls the fuel injection valve 27 so as to increase the amount of fuel supplied from the fuel injection valve 27, that is, to increase the fuel injection amount. As a result, the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 21 becomes rich, the temperature of the exhaust gas is lowered, and the temperatures of the exhaust passage 23 material, the catalysts 51 and 52, the exhaust valve seat, etc. are lowered. Can do.

  In addition, the control unit 31 determines that the mode of the transmission 10 is the fixed mode and at least one of the temperatures of the exhaust passage 23 material, the catalysts 51 and 52, the exhaust valve seat, and the like is higher than the corresponding temperature threshold. In such a case, typically, the fuel injection valve 27 is controlled so as to increase the fuel injection amount. As a result, the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 21 becomes rich, the temperature of the exhaust gas is lowered, and the temperatures of the exhaust passage 23 material, the catalysts 51 and 52, the exhaust valve seat, etc. are lowered. Can do.

  Next, transmission control processing executed by the ECU 30 in the vehicle 1 on which the control device 300 configured as described above is mounted will be described with reference to the flowchart of FIG. This transmission control process is periodically executed every several milliseconds to several tens of milliseconds, for example, regularly or irregularly while the vehicle is running.

  In FIG. 3, first, the temperature estimation unit 33 determines the temperature of the exhaust passage 23 material, the catalyst based on the intake air amount detected by the air flow meter 25 and the rotational speed of the internal combustion engine 21 detected by the rotational speed sensor 41. The temperature of 51 and 52, the temperature of an exhaust valve seat, etc. are estimated (step S101). Next, the determination part 32 determines whether the mode of the transmission 10 is a shift mode (step S102).

  When it is determined that the mode is not the speed change mode (that is, the fixed mode) (step S102: No), subsequently, the process of step S107 described later is performed. On the other hand, when it is determined that the speed change mode is set (step S102: Yes), the determination unit 32 subsequently determines whether or not the estimated temperature is higher than the temperature threshold (step S103). When it is determined that the temperature is lower than the temperature threshold (step S103: No), the process is temporarily terminated. After this determination, the determination unit 32 determines whether or not the other switching conditions are satisfied. If it is determined that the other switching conditions are satisfied, the control unit 31 determines whether the transmission 10 The step of controlling the transmission 10 to switch the mode to the fixed mode, and if it is determined that the mode is not satisfied, the control unit 31 does not switch the mode of the transmission 10 to the fixed mode (that is, the transmission mode is changed). There may be a step of controlling the transmission 10 (to maintain).

  When it is determined that the temperature is higher than the temperature threshold (step S103: Yes), the determination unit 32 subsequently determines whether or not the fixed mode prohibition condition is satisfied by switching the mode of the transmission 10 to the fixed mode ( Step S104). That is, it is determined whether or not the vibration generated in the detected power transmission system or the like is larger than a predetermined value or within a predetermined range. Alternatively, it is determined whether or not the fixed mode prohibition flag is set.

  When it is determined that the fixed mode prohibition condition is satisfied (step S104: Yes), the control unit 31 controls the fuel injection valve 27 so as to increase the fuel injection amount (step S108), and the process is temporarily terminated. .

  When it is determined that the fixed mode prohibition condition is not satisfied (step S104: No), the control unit 31 controls the transmission 10 so as to switch the mode of the transmission 10 to the fixed mode, and discharges the exhaust gas to the internal combustion engine 21. Therefore, the EGR device 60 is controlled to open the EGR control valve 62 (step S105). Next, the temperature estimation unit 33 estimates the temperature of the exhaust passage 23 material, the temperatures of the catalysts 51 and 52, the temperature of the exhaust valve seat, and the like based on the newly detected intake air amount and the rotational speed of the internal combustion engine 21. (Step S106).

  Next, the determination unit 32 determines whether or not the estimated temperature is higher than the temperature threshold (step S107). When it is determined that the temperature is lower than the temperature threshold (step S107: No), the process is temporarily terminated. On the other hand, when it determines with it being higher than a temperature threshold value (step S107: Yes), the control part 31 controls the fuel injection valve 27 so that the amount of fuel injections may be increased (step S108), and once complete | finishes a process. .

  It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed within a scope not departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a vehicle with such a change. These control devices and methods are also included in the technical scope of the present invention.

1 is a block diagram of a vehicle according to an embodiment of the present invention. It is a characteristic view showing an example of an operation line showing the operation of the internal combustion engine according to the embodiment of the present invention. It is a flowchart which shows the transmission control process in ECU which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 10 ... Transmission, 11 ... Power control unit, 12 ... Storage battery, 13 ... Drive shaft, 14 ... Front wheel, 21 ... Internal combustion engine, 22 ... Intake passage, 23 ... Exhaust passage, 24 ... Air cleaner, 25 ... Air flow Meter, 26 ... Throttle valve, 27 ... Fuel injection valve, 28 ... Fuel container, 30 ... ECU, 31 ... Control unit, 32 ... Determination unit, 33 ... Temperature estimation unit, 34 ... Storage unit, 35 ... Input / output unit, 41 Rotational speed sensor, 42 Air-fuel ratio sensor, 43 Oxygen sensor, 51, 52 Catalyst, 60 EGR device, 61 EGR cooler, 62 EGR control valve, 101 Power distribution mechanism, 102 Motor generator 103 ... Generator, 104 ... Speed reducer, 300 ... Control device

Claims (7)

An internal combustion engine, fuel supply means for supplying fuel to the internal combustion engine, exhaust gas recirculation means capable of recirculating at least part of exhaust gas discharged from the internal combustion engine to the internal combustion engine, and output of the internal combustion engine A vehicle control device comprising: a transmission mode capable of continuously changing a transmission ratio; and a transmission capable of mutually switching between a fixed mode in which the transmission ratio cannot be changed continuously,
Temperature detecting means for detecting the temperature of the exhaust gas;
The exhaust gas recirculation is performed so that the transmission is controlled to switch to the fixed mode on the condition that the detected temperature is higher than a temperature threshold, and at least a part of the exhaust gas is recirculated to the internal combustion engine. And a control means for controlling the means. The control means includes
Determining means for determining whether the detected temperature is higher than the temperature threshold;
When it is determined that the temperature is higher than the temperature threshold, the transmission is controlled to switch to the fixed mode, and the exhaust gas recirculation means is controlled to recirculate at least a part of the exhaust gas to the internal combustion engine. The vehicle control device according to claim 1, wherein when it is determined that the temperature is lower than the temperature threshold, the transmission is controlled so as not to switch to the fixed mode.   The vehicle control device according to claim 1, wherein a speed ratio in the fixed mode is smaller than a speed ratio in the speed change mode. A rotational speed detection means for detecting the rotational speed of the internal combustion engine;
Intake air detection means for detecting the amount of intake air sucked into the internal combustion engine,
4. The vehicle control according to claim 1, wherein the temperature detection unit detects the temperature based on the detected rotation speed and the detected intake air amount. 5. apparatus.   The control means is configured to increase the supply amount of the fuel supplied to the internal combustion engine on the condition that the detected temperature is higher than a temperature threshold when the transmission is in the fixed mode. The vehicle control device according to any one of claims 1 to 4, wherein the fuel supply means is controlled.   If the transmission cannot be controlled to switch to the fixed mode, the control means increases the supply amount of the fuel supplied to the internal combustion engine on the condition that the detected temperature is higher than a temperature threshold. The vehicle control apparatus according to claim 1, wherein the fuel supply unit is controlled as described above. An internal combustion engine, fuel supply means for supplying fuel to the internal combustion engine, exhaust gas recirculation means capable of recirculating at least part of exhaust gas discharged from the internal combustion engine to the internal combustion engine, and output of the internal combustion engine A vehicle control method comprising: a speed change mode capable of continuously changing a speed change ratio; and a transmission capable of switching between a fixed mode where the speed change ratio cannot be changed continuously.
A temperature detection step of detecting a temperature related to the exhaust gas;
The exhaust gas recirculation is performed so that the transmission is controlled to switch to the fixed mode on the condition that the detected temperature is higher than a temperature threshold, and at least a part of the exhaust gas is recirculated to the internal combustion engine. And a control step for controlling the means.

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