JP5966847B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device, and more particularly to a technique for controlling an engine that drives a pump that supplies oil to an electric motor mounted on a vehicle as a drive source.

  Generally, oil for lubrication, operation, cooling, and the like is supplied from an oil pump to a transmission mounted on a vehicle. As an example, the oil pump is driven by an engine.

  However, in a hybrid vehicle capable of intermittently stopping the engine, when the engine is stopped, the oil pump is not driven, so that the oil supply to the electric motor can be interrupted. Accordingly, if the engine is stopped for a long time, the temperature of the electric motor can be increased because the electric motor cannot be cooled with oil.

  In order to prevent an increase in the temperature of the electric motor, a technique for limiting the intermittent stop of the engine according to the temperature of the electric motor or the gradient of the road surface has been proposed as disclosed in JP 2011-245886 (Patent Document 1). Japanese Patent Application Laid-Open No. 2011-245886 describes that in FIG. 3 and FIG. 4, the lower the engine speed is increased as the temperature of the electric motor is higher or the road surface gradient is larger. Yes.

JP 2011-245886 A

  However, even if the lower limit value of the engine speed is increased, the amount of oil supplied increases and the cooling capacity of the electric motor improves, but the amount of heat generated by the electric motor itself cannot be reduced. Therefore, if the heat generation amount exceeds the cooling amount, the temperature of the electric motor continues to rise. Moreover, since the engine speed is determined by the vehicle speed and the transmission gear ratio, it is not easy to change the engine speed alone without any restrictions.

  This invention is made | formed in view of the above-mentioned subject, The objective is to suppress the temperature rise of the electric motor as a drive source.

  In the vehicle, an engine and an electric motor are mounted as drive sources. The pump that supplies oil to the electric motor is driven by the engine. The vehicle control device includes means for detecting the temperature of the electric motor, and control means for increasing the output torque of the engine as the temperature of the electric motor increases during driving of the engine.

  By increasing the output torque of the engine, the contribution rate of the electric motor to the driving force for traveling can be reduced. Therefore, it is possible to reduce the load of the electric motor and reduce the heat generation amount of the electric motor. As a result, the temperature rise of the electric motor can be suppressed.

  The engine output shaft rotational speed may be increased in synchronization with the engine output torque. Thereby, the amount of oil supplied to the electric motor can be increased to cool the electric motor. Further, since the output shaft rotational speed is increased in synchronization with the output torque, the increased driving sound of the pump can be drowned out by the operating noise of the engine increased as the output torque increases.

  The engine output shaft rotational speed may be increased as the temperature of the electric motor is higher, and the engine output shaft rotational speed may be increased as the slope of the uphill road is larger. Thereby, the amount of oil supplied to the electric motor can be increased to cool the electric motor.

  The engine may be operated when the running power of the vehicle is equal to or higher than a predetermined threshold value, and the threshold value may be lowered as the temperature of the electric motor is higher. Alternatively, the threshold may be lowered as the slope of the uphill road increases. Thereby, the area | region which an engine drives can be expanded and the load of an electric motor can be reduced.

It is a figure which shows the outline of a hybrid vehicle. It is a figure which shows a power transmission device. It is a figure which shows the area | region which an engine drives. It is a figure which shows the engine starting threshold value for every coil temperature. It is a figure which shows the area | region where EV mode is canceled or rejected. It is a figure which shows the operating line of an engine. It is a figure which shows the operating line for every coil temperature. It is a figure which shows the engine speed for every coil temperature.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  Referring to FIG. 1, an engine 100, a power transmission device 102 connected to engine 100, and a battery 104 are mounted on the vehicle. The power transmission device 102 includes a first motor generator 110, a second motor generator 120, a power split mechanism 130, a speed reducer 140, and a cover module 300 described later. In the following description, a hybrid vehicle will be described as an example. However, an electric vehicle that is mainly equipped with an engine for generating power and has an cruising range extension function (range extender) or an electric vehicle called a range extended electric vehicle is used. Also good.

  This vehicle travels by driving force from at least one of engine 100 and second motor generator 120. That is, either one or both of engine 100 and second motor generator 120 is automatically selected as a drive source according to the operating state.

  For example, engine 100 and second motor generator 120 are controlled according to the result of the driver operating an accelerator pedal (not shown). The operation amount (accelerator opening) of the accelerator pedal is detected by an accelerator opening sensor (not shown).

  When the accelerator opening is small and the vehicle speed is low, the hybrid vehicle runs using only the second motor generator 120 as a drive source. In this case, engine 100 is stopped. However, the engine 100 may be driven for power generation or the like.

  Further, when the accelerator opening is large, the vehicle speed is high, or the remaining capacity (SOC: State Of Charge) of battery 150 is small, engine 100 is driven. In this case, the hybrid vehicle runs using only engine 100 or both engine 100 and second motor generator 120 as drive sources.

  Engine 100, first motor generator 110, and second motor generator 120 are controlled by an ECU (Electronic Control Unit) 400. ECU 400 may be divided into a plurality of ECUs. For example, ECU 400 is divided into an ECU for controlling engine 100, an ECU for controlling first motor generator 110 and second motor generator 120, and an ECU that generally manages these ECUs. May be.

  In the present embodiment, ECU 400 controls engine 100 based on the temperature of second motor generator 120 and the gradient of the road surface. A method for controlling the engine 100 will be described later in detail. The temperature of second motor generator 120 is detected by temperature sensor 401 and input to ECU 400. The slope of the road surface, more specifically, the slope of the uphill road is calculated based on the acceleration detected by the acceleration sensor 402 or the like. Since a known technique may be used for the method of calculating the gradient, the description thereof will not be repeated here.

  The engine 100 is an internal combustion engine. As the fuel / air mixture burns in the combustion chamber, the crankshaft as the output shaft rotates.

  The battery 104 is an assembled battery configured by connecting a plurality of battery modules in which a plurality of battery cells are integrated in series. The voltage of the battery 104 is about 200V, for example. A capacitor may be used instead of or in addition to the battery 104.

  Engine 100, first motor generator 110, and second motor generator 120 are connected via power split mechanism 130. The power generated by the engine 100 is divided into two paths by the power split mechanism 130. One is a path for driving the front wheels 160 via the speed reducer 140. The other is a path for driving the first motor generator 110 to generate power.

  The power generated by engine 100 is transmitted to mechanical oil pump 170. Mechanical oil pump 170 is driven by engine 100 and supplies oil for cooling and lubrication to first motor generator 110, second motor generator 120, and power split mechanism 130. As an example, the mechanical oil pump 170 is a trochoid oil pump having an external gear and an internal gear, but other types of oil pumps may be used.

  First motor generator 110 is a three-phase AC rotating electric machine including a U-phase coil, a V-phase coil, and a W-phase coil. First motor generator 110 generates power using the power of engine 100 divided by power split mechanism 130. The electric power generated by the first motor generator 110 is selectively used according to the running state of the vehicle and the remaining capacity of the battery 104. For example, during normal traveling, the electric power generated by first motor generator 110 becomes electric power for driving second motor generator 120 as it is. On the other hand, when the SOC of battery 104 is lower than a predetermined value, the electric power generated by first motor generator 110 is stored in battery 104.

  When first motor generator 110 is acting as a generator, first motor generator 110 generates negative torque. Here, the negative torque means a torque that becomes a load on engine 100. When first motor generator 110 is supplied with electric power and acts as a motor, first motor generator 110 generates positive torque. Here, the positive torque means a torque that does not become a load on the engine 100, that is, a torque that assists the rotation of the engine 100. The same applies to the second motor generator 120.

  Second motor generator 120 is a three-phase AC rotating electric machine including a U-phase coil, a V-phase coil, and a W-phase coil. As described above, the temperature sensor 401 detects the temperature of the second motor generator 120, more specifically, the temperature of the coil of the second motor generator 120.

  Second motor generator 120 is driven by at least one of the electric power stored in battery 104 and the electric power generated by first motor generator 110.

  The driving force of the second motor generator 120 is transmitted to the front wheels 160 via the speed reducer 140. As a result, the second motor generator 120 assists the engine 100 or causes the vehicle to travel by the driving force from the second motor generator 120. The rear wheels may be driven instead of or in addition to the front wheels 160.

  During regenerative braking of the hybrid vehicle, the second motor generator 120 is driven by the front wheels 160 via the speed reducer 140, and the second motor generator 120 operates as a generator. Accordingly, second motor generator 120 operates as a regenerative brake that converts braking energy into electric power. The electric power generated by second motor generator 120 is stored in battery 104.

  Power split device 130 includes a planetary gear including a sun gear, a pinion gear, a carrier, and a ring gear. The pinion gear engages with the sun gear and the ring gear. The carrier supports the pinion gear so that it can rotate. The sun gear is connected to the rotation shaft of first motor generator 110. The carrier is connected to the crankshaft of engine 100. Ring gear is connected to the rotation shaft of second motor generator 120 via a planetary gear different from power split mechanism 130. The ring gear is further connected to the speed reducer 140.

  In the present embodiment, first motor generator 110, second motor generator 120, power split mechanism 130, and reduction gear 140 are housed in case 200. In a vehicle in which only the engine 100 is mounted as a drive source, a gear or the like constituting the transmission may be accommodated in the case 200.

  Case 200 defines a part of the outer shape of power transmission device 102, and one side is attached to engine 100. A cover module 300 is further attached to the other side of the case 200. More specifically, a cover 310 that is one of the components constituting the cover module 300 is attached to the other side of the case 200.

  The cover module 300 includes a cover 310 and the mechanical oil pump 170 described above. An oil path is formed inside the cover 310. The mechanical oil pump 170 described above is housed inside the cover 310 and supplies oil to the oil passage in the cover 310. Oil is supplied from an oil passage in the cover 310 toward a lubrication passage in the case 200.

  The cover 310 includes an oil pump cover 311 attached to the case 200 and a rear cover 312 attached to the oil pump cover 311 on the side opposite to the side attached to the case 200.

  As an example, the external gear and the internal gear of the mechanical oil pump 170 described above are accommodated in the oil pump cover 311. In addition, the oil pump cover 311 further accommodates a hydraulic pressure adjustment component 314 that adjusts the hydraulic pressure supplied toward the case 200. As an example, the hydraulic pressure adjustment component 314 is a relief valve that limits the hydraulic pressure below a predetermined hydraulic pressure. The relief valve as the hydraulic pressure adjusting component 314 opens when the pressure of the oil passage in the cover module 300 becomes a predetermined value or more, and returns the oil into the case 200, for example. The returned oil stays in the lower part of case 200 as an example, and is used for stirring lubrication of gears and the like. You may make it return oil to an oil pan.

  As an example, the external gear and the internal gear of the mechanical oil pump 170 and the hydraulic pressure adjustment component 314 are oil pumps from the joint surface side between the oil pump cover 311 and the rear cover 312 with the rear cover 312 removed from the oil pump cover 311. The cover 311 is assembled. After the external gear and the internal gear of the mechanical oil pump 170 and the hydraulic adjustment component 314 are assembled to the oil pump cover 311, the rear cover 312 is attached to the oil pump cover 311 using bolts or the like.

  With reference to FIG. 2, the oil path provided in the cover module 300 and the lubrication path in the case 200 will be further described.

  The cover module 300 is provided with at least oil passages 321, 322 and 323. A part of the oil passage provided in the cover module 300 is an elongated cavity provided in each of the oil pump cover 311 and the rear cover 312, and a part is constituted by the oil pump cover 311 and the rear cover 312. For example, the oil path 323 is configured by the groove provided in the rear cover 312 and the plane of the oil pump cover 311.

  The oil passage 321 is sucked up from an oil pan (not shown) below the case 200 and guides the oil that has passed through the strainer 215 to the mechanical oil pump 170.

  The oil passage 322 guides the oil discharged from the mechanical oil pump 170 to the oil passage 201 provided in the case 200. The oil supplied to the oil passage 201 is finally supplied to the power split mechanism 130.

  The oil passage 323 guides the oil discharged from the mechanical oil pump 170 to a tube 330 that connects the cover module 300 and the case 200. One end of the tube 330 is connected to the oil passage 323 of the cover module 300, and the other end is connected to the oil passage 202 of the case 200. The oil supplied to the oil passage 202 is finally supplied to the first motor generator 110 and the second motor generator 120 via the oil cooler 210. The pressure in the oil passage 323 is limited by a relief valve as the hydraulic pressure adjustment component 314.

  With reference to FIG. 3, the control mode of engine 100 will be further described. As shown in FIG. 3, when the required power required to be output to the hybrid vehicle is smaller than the engine start threshold value, the hybrid vehicle travels using only the driving force of second motor generator 120.

  The required power is set as a traveling power (output power) used for traveling the hybrid vehicle. The required power is calculated by ECU 170 according to a map having, for example, the accelerator opening and the vehicle speed as parameters. The method for calculating the required power is not limited to this. Note that torque, acceleration, driving force, accelerator opening, and the like may be used instead of power.

  When the required power of the hybrid vehicle exceeds the engine start threshold value, engine 100 is driven. Thus, the hybrid vehicle travels using the driving force of engine 100 in addition to or instead of the driving force of second motor generator 120. Further, the electric power generated by first motor generator 110 using the driving force of engine 100 is directly supplied to second motor generator 120.

  As shown in FIG. 4, in the present embodiment, ECU 400 is changed so that the engine start threshold value decreases as the temperature of second motor generator 120 increases. Further, the engine starting threshold value is set to be smaller as the road surface, more specifically, the slope of the uphill road is larger.

  In addition to the engine 100 being automatically started or stopped, the engine 100 can also be stopped when the driver requests an EV mode in which the vehicle travels using only the second motor generator 120 by operating a switch. However, when the temperature of second motor generator 120 is equal to or higher than the threshold value shown in FIG. 5, engine 100 is operated without being stopped. That is, the EV mode is rejected (rejected). Further, when the temperature of second motor generator 120 rises to a threshold value while engine 100 is stopped, engine 100 is started. That is, the EV mode is cancelled. As shown in FIG. 5, the threshold value for the temperature of the second motor generator 120 is determined so as to decrease as the gradient of the road surface (uphill road) increases.

  As shown in FIG. 6, the operating point of engine 100, that is, engine speed NE and output torque TE are determined by the intersection of the output power of engine 100 and the operating line.

  The output power of engine 100 is indicated by an isopower line. The operating line is predetermined by the developer based on the results of experiments and simulations. The operation line is set so that the engine 100 can be driven so that the fuel consumption becomes optimum (minimum). That is, when the engine 100 is driven along the operation line, optimal fuel consumption is realized.

  In the present embodiment, as shown in FIG. 7, the operating line is changed so that the output torque increases as the temperature of second motor generator 120 increases while engine 100 is driven. That is, the output torque of engine 100 is increased by changing the operation line.

  Further, as shown in FIG. 8, engine 100 is driven such that the engine speed increases as the temperature of second motor generator 120 increases. The engine speed is increased as the slope of the road surface (uphill road) is larger. The engine speed may be increased in synchronization with the output torque of engine 100.

  Note that in a vehicle provided with an electric oil pump in addition to the mechanical oil pump 170, the higher the temperature of the second motor generator 120, the higher the rotational speed of the electric oil pump and the slope of the road surface (uphill road). You may make it enlarge the rotation speed of an electric oil pump, so that it is large. The rotational speed of the electric oil pump may be increased in synchronization with the output torque of engine 100.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 100 Engine, 102 Power transmission device, 104 Battery, 110 1st motor generator, 120 2nd motor generator, 130 Power split mechanism, 140 Reduction gear, 160 Front wheel, 170 Mechanical oil pump, 200 Case, 201, 202 Oil path, 210 oil cooler, 215 strainer, 300 cover module, 310 cover, 311 oil pump cover, 312 rear cover, 314 oil pressure adjustment part, 321, 322, 323 oil passage, 330 tube, 341 check valve, 400 ECU, 401 temperature sensor, 402 Acceleration sensor.

Claims (4)

An engine and an electric motor are mounted as drive sources, and the vehicle control apparatus drives a pump for supplying oil to the electric motor by the engine,
Means for detecting the temperature of the electric motor;
Control means for increasing the output torque of the engine as the temperature of the electric motor is higher during driving of the engine;
Means for driving the engine if the running power of the vehicle is greater than or equal to a predetermined threshold;
And a means for lowering the threshold value as the slope of the uphill road is larger . The vehicle control device according to claim 1, further comprising means for increasing an output shaft rotational speed of the engine as the output torque of the engine increases. Means for increasing the output shaft speed of the engine as the temperature of the electric motor is higher;
The vehicle control device according to claim 1, further comprising means for increasing the output shaft rotational speed of the engine as the slope of the uphill road increases. And means for temperature before Symbol electric motor to lower the higher the threshold, the control apparatus for a vehicle according to claim 1.

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