Hybrid vehicles

Abstract

To suppress deterioration of fuel consumption on a low land.SOLUTION: A hybrid vehicle includes an engine, a motor capable of outputting power for traveling, and a control device that controls the engine and the motor so as to travel with intermittent operation of the engine. The control device inhibits intermittent stop of the engine when an atmospheric pressure condition that atmospheric pressure is equal to or higher than a predetermined pressure is satisfied. When the atmospheric pressure is equal to or higher than the predetermined pressure, the air density becomes high, the compression reaction force at the start of the engine becomes large, and a large cranking torque is required as compared with a case where the atmospheric pressure is approximately normal, so that fuel efficiency deteriorates. However, inhibiting the intermittent stop of the engine makes it possible to suppress the deterioration of the fuel efficiency.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle in which an engine and a motor are controlled so as to run with intermittent operation of the engine. [Background technology]

[0002] Conventionally, as this type of hybrid vehicle, a hybrid vehicle has been proposed in which the output shaft of the engine and the input shaft of an automatic transmission are connected via a clutch and a motor is attached to the input shaft of the automatic transmission (see, for example, Patent Document 1). This hybrid vehicle performs motor running, where the vehicle runs only on the power of the motor with the clutch disengaged and the engine stopped, and hybrid running, where the vehicle runs on the power from both the engine and the motor with the clutch engaged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-111276 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned hybrid vehicle, when the engine is operated intermittently at low altitudes such as mining sites, the startability of the engine may be reduced. At low altitudes, the atmospheric pressure is higher and the air density is higher than on flat ground, so the compression reaction force at the time of starting the engine is large. For this reason, if an attempt is made to start the engine with the same cranking torque as on flat ground, the engine may not start due to insufficient cranking torque. To address this issue, it is possible to carry out control to increase the cranking torque, but in this case, the motor would become larger and power consumption would increase, resulting in poor fuel efficiency.

[0005] The main object of the hybrid vehicle of the present invention is to suppress deterioration of fuel efficiency at low altitudes. [Means for solving the problem]

[0006] The hybrid vehicle of the present invention employs the following means to achieve the above-mentioned main object.

[0007] The hybrid vehicle of the present invention is A hybrid vehicle including an engine, a motor capable of outputting power for driving, and a control device that controls the engine and the motor so as to drive with intermittent operation of the engine, The control device prohibits intermittent stopping of the engine when an atmospheric pressure condition is established in which the atmospheric pressure is equal to or higher than a predetermined pressure. It is characterized by:

[0008] In the hybrid vehicle of the present invention, when the atmospheric pressure condition is satisfied, that is, the atmospheric pressure is equal to or higher than the predetermined pressure, the intermittent stopping of the engine is prohibited. This makes it possible to suppress the deterioration of fuel efficiency caused by the deterioration of engine startability due to intermittent operation when the atmospheric pressure is equal to or higher than the predetermined pressure. In addition, since there is no need to increase the cranking torque to start the engine, there is no need to increase the size of the motor.

[0009] In such a hybrid vehicle of the present invention, the control device may prohibit intermittent stopping of the engine when an oil temperature condition is satisfied, in which the temperature of hydraulic oil lubricating the engine is equal to or lower than a predetermined temperature, in addition to the atmospheric pressure condition being satisfied. When the temperature of the hydraulic oil is low, the viscosity of the hydraulic oil increases, and the startability of the engine decreases. Therefore, by prohibiting intermittent stopping of the engine when the oil temperature condition is satisfied, the deterioration of fuel efficiency due to the deterioration of engine startability caused by intermittent operation can be more appropriately suppressed. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. [Diagram 2] 10 is a flowchart showing an example of an intermittent stop permission / denial routine executed by the HVECU 70. [Diagram 3] FIG. 11 is a diagram showing an outline of the configuration of a hybrid vehicle 120 according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, a mode for carrying out the present invention will be described using examples. EXAMPLES

[0012] 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a motor 30, an inverter 32, a clutch K0, an automatic transmission 40, a high-voltage battery 60, a low-voltage battery 62, a DC / DC converter 64, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0013] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel from a fuel tank. A crankshaft 23 of the engine 22 is connected to a rotating shaft 31 (rotor) of a motor 30 via a clutch K0. The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0014] The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, not shown. Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 via an input port. Examples of signals input to the engine ECU 24 include a crank angle θcr from a crank position sensor 23a that detects the rotational position of the crankshaft 23 of the engine 22, a coolant temperature Tw from a water temperature sensor (not shown) that detects the temperature of the coolant for the engine 22, and an oil temperature Toil from an oil temperature sensor 47 attached to an oil pan 46 that stores hydraulic oil that lubricates the engine 22 and the automatic transmission 40. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via an output port. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the crankshaft 23 from the crank position sensor 23a.

[0015] A starter motor 25 for cranking the engine 22 and an alternator 26 for generating electricity using power from the engine 22 are connected to the crankshaft 23 of the engine 22. The starter 25 and the alternator 26 are connected to a low-voltage side power line 63 together with a low-voltage battery 62, and are controlled by the HVECU 70.

[0016] The motor 30 is configured as a synchronous generator motor, and has a rotor in which a permanent magnet is embedded in a rotor core, and a stator in which a three-phase coil is wound around a stator core. A rotating shaft 31 to which the rotor of the motor 30 is fixed is connected to the crankshaft 23 of the engine 22 via a clutch K0, and is also connected to an input shaft 41 of an automatic transmission 45. The inverter 32 is used to drive the motor 30, and is connected to a high-voltage power line 61. The motor 30 is rotationally driven by a motor electronic control unit (hereinafter referred to as "motor ECU") 34 controlling the switching of multiple switching elements of the inverter 32.

[0017] The motor ECU 34 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, not shown. Signals from various sensors are input to the motor ECU 34 via the input ports. Examples of signals input to the motor ECU 34 include a rotational position θm from a rotational position sensor 30a that detects the rotational position of the rotor (rotating shaft 31) of the motor 30, and phase currents Iu and Iv from current sensors that detect the phase currents of the respective phases of the motor 30. A control signal to the inverter 32 and the like are output from the motor ECU 34 via the output port. The motor ECU 34 is connected to the HVECU 70 via a communication port. The motor ECU 34 calculates the rotational speed Nm of the motor 30 based on the rotational position θm of the rotor (rotating shaft 31) of the motor 30 from the rotational position sensor 30a.

[0018] The clutch K0 is configured as, for example, a hydraulically driven friction clutch, and is controlled by the HVECU 70 to connect and disconnect the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30.

[0019] The automatic transmission 40 has a torque converter 43 and a six-speed automatic transmission 45. The torque converter 43 is configured as a general fluid transmission device, and transmits the power of an input shaft 41 connected to a rotating shaft 31 of the motor 30 to a transmission input shaft 44 which is an input shaft of the automatic transmission 45 with amplified torque, or transmits the torque as is without amplifying it. The automatic transmission 45 has the transmission input shaft 44, an output shaft 42 connected to driving wheels 49 via a differential gear 48, a plurality of planetary gears, and a plurality of hydraulically driven friction engagement elements (clutches, brakes). Each of the plurality of friction engagement elements has a hydraulic servo composed of a piston, a plurality of friction engagement plates (friction plates and separator plates), an oil chamber to which hydraulic oil is supplied, and the like. The automatic transmission 45 forms forward gears from 1st gear to 6th gear and reverse gears by engaging and disengaging a plurality of friction engagement elements, and transmits power between the transmission input shaft 44 and the output shaft 42. The hydraulic pressure of hydraulic oil from a mechanical oil pump or an electric oil pump is adjusted and supplied to the clutch K0 and the automatic transmission 45 by a hydraulic control device (not shown). The hydraulic control device has a valve body with a plurality of oil passages formed therein, a plurality of regulator valves, a plurality of linear solenoid valves, etc. This hydraulic control device is controlled by the HVECU 70.

[0020] High-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery with a rated voltage of several hundred volts, and is connected to high-voltage power line 61 together with inverter 32. Low-voltage battery 62 is configured as, for example, a lead-acid battery with a rated voltage of about 12 V or 14 V, and is connected to low-voltage power line 63 together with starter motor 25 and alternator 26. DC / DC converter 64 is connected to high-voltage power line 61 and low-voltage power line 63. This DC / DC converter 64 supplies power from high-voltage power line 61 to low-voltage power line 63 with a voltage step-down.

[0021] Although not shown, the HVECU 70 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. Signals from various sensors are input to the HVECU 70 via the input port. Examples of signals input to the HVECU 70 include the rotation speed Nin from the rotation speed sensor 41a attached to the input shaft 41 of the automatic transmission 40, the rotation speed Nmi from the rotation speed sensor 44a attached to the transmission input shaft 44 of the automatic transmission 40, and the rotation speed Nout from the rotation speed sensor 42a attached to the output shaft 42 of the automatic transmission 40. Examples of signals input to the HVECU 70 include the voltage Vbh of the high-voltage battery 60 from a voltage sensor attached between the terminals of the high-voltage battery 60, the current Ibh of the high-voltage battery 60 from a current sensor attached to the output terminal of the high-voltage battery 60, and the voltage Vbl from a voltage sensor attached between the terminals of the low-voltage battery 62. Examples of such inputs include an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, a vehicle speed V from a vehicle speed sensor 87, and an atmospheric pressure Pa from an atmospheric pressure sensor 88.

[0022] Various control signals are output from the HVECU 70 via an output port. Examples of signals output from the HVECU 70 include a control signal to the starter motor 25 and a control signal to the alternator 26. Examples of signals output from the HVECU 70 include a control signal to the clutch K0 and the automatic transmission 40 (hydraulic control device), and a control signal to the DC / DC converter 64. The HVECU 70 is connected to the engine ECU 24 and the motor ECU 34 via a communication port. The HVECU 70 calculates a rotation speed ratio Gt of the automatic transmission 40 by dividing the rotation speed Nin of the input shaft 41 of the automatic transmission 40 from the rotation speed sensor 41a by the rotation speed Nout of the output shaft 42 of the automatic transmission 40 from the rotation speed sensor 42a.

[0023] In the hybrid vehicle 20 of the embodiment thus configured, the engine 22, the clutch K0, the motor 30, and the automatic transmission 40 are controlled by cooperative control between the HVECU 70, the engine ECU 24, and the motor ECU 34 so as to travel in a hybrid travel mode (HV travel mode) or an electric travel mode (EV travel mode). Here, the HV travel mode is a mode in which the clutch K0 is engaged and the vehicle travels using the power of the engine 22, and the EV travel mode is a mode in which the clutch K0 is released and the operation of the engine 22 is stopped and the vehicle travels. When switching from the EV travel mode to the HV travel mode, the engine 22 is started. At this time, the engine 22 is started by switching the clutch K0 from a half-engaged state to an engaged state while outputting a cranking torque from the motor 30. Therefore, the motor 30 outputs a torque equal to the sum of the torque for travel and the cranking torque.

[0024] In controlling the automatic transmission 40 in the HV driving mode or the EV driving mode, the HVECU 70 first sets a target gear M* of the automatic transmission 45 based on the accelerator opening Acc and the vehicle speed V. Then, when the gear M of the automatic transmission 45 matches the target gear M*, the HVECU 70 controls the automatic transmission 45 so that the gear M is maintained. On the other hand, when the gear M and the target gear M* differ, the HVECU 70 controls the automatic transmission 45 so that the gear M matches the target gear M*.

[0025] Next, a description will be given of the operation of the hybrid vehicle 20 of the embodiment thus configured, in particular, the operation when prohibiting or permitting intermittent stopping of the engine 22. Fig. 2 is a flowchart showing an example of an intermittent stop permission / prohibition routine executed by the HVECU 70. This routine is repeatedly executed at predetermined time intervals after the engine 22 is started.

[0026] When the intermittent stop permission routine is executed, the HVECU 70 first executes a process of inputting data required for determining whether intermittent stop of the engine 22 is permitted, such as the atmospheric pressure Pa and the oil temperature Toil from the atmospheric pressure sensor 88 (step S100). Here, the oil temperature Toil is detected by the oil temperature sensor 47 and input from the engine ECU 24 via communication in this embodiment.

[0027] Next, it is determined whether the atmospheric pressure Pa is equal to or higher than a predetermined pressure Pref (step S110), and whether the oil temperature Toil is lower than a predetermined temperature Tref (step S120). The predetermined pressure Pref can be a value higher than the atmospheric pressure under normal conditions on flat ground (e.g., 106 kPa, 107 kPa, 108 kPa, etc.). The predetermined temperature Tref can be a temperature near the upper limit at which the viscosity of the hydraulic oil becomes relatively high (e.g., 15°C, 20°C, 25°C, etc.).

[0028] When it is determined in step S110 that the atmospheric pressure Pa is less than the predetermined pressure Pref, or when it is determined in step S110 that the atmospheric pressure Pa is equal to or greater than the predetermined pressure Pref but it is determined in step S120 that the oil temperature Toil is equal to or greater than the predetermined temperature Tref, it is determined that there is no need to prohibit intermittent stopping of the engine 22 based on the atmospheric pressure Pa, and intermittent stopping of the engine 22 is permitted (step S130), and this routine is terminated.

[0029] On the other hand, when it is determined in step S110 that the atmospheric pressure Pa is equal to or higher than the predetermined pressure Pref and when it is determined in step S120 that the oil temperature Toil is lower than the predetermined temperature Tref, the intermittent stopping of the engine 22 is prohibited (step S140), and this routine is terminated. When the atmospheric pressure Pa is equal to or higher than the predetermined pressure Pref, the air density increases, the compression reaction force at the start of the engine 22 increases, and the startability of the engine 22 decreases compared to when the atmospheric pressure Pa is at a normal level. Also, when the oil temperature Toil is lower than the predetermined temperature Tref, the viscosity of the hydraulic oil increases, and the startability of the engine 22 decreases. Therefore, when both the atmospheric pressure condition in which the atmospheric pressure Pa is equal to or higher than the predetermined pressure Pref and the oil temperature condition in which the oil temperature Toil is lower than the predetermined temperature Tref are satisfied, the startability of the engine 22 decreases, and a large cranking torque is required to start the engine 22. This causes a decrease in fuel efficiency and a need to increase the size of the motor 30. In this embodiment, when both the atmospheric pressure condition and the oil temperature condition are satisfied, the intermittent stopping of the engine 22 is prohibited, thereby preventing deterioration of fuel economy and preventing the size of the motor 30 from increasing.

[0030] In the hybrid vehicle 20 of the embodiment described above, when both an atmospheric pressure condition where the atmospheric pressure Pa is equal to or higher than a predetermined pressure Pref and an oil temperature condition where the oil temperature Toil is lower than a predetermined temperature Tref are satisfied, intermittent stopping of the engine 22 is prohibited. This makes it possible to suppress inconveniences (such as worsening fuel economy and enlarging the size of the motor 30) that arise from increasing the cranking torque when starting the engine 22 in order to avoid deterioration of the startability of the engine 22.

[0031] In the hybrid vehicle 20 of the embodiment, when both an atmospheric pressure condition where the atmospheric pressure Pa is equal to or higher than the predetermined pressure Pref and an oil temperature condition where the oil temperature Toil is lower than the predetermined temperature Tref are satisfied, the intermittent stopping of the engine 22 is prohibited. However, when the atmospheric pressure condition where the atmospheric pressure Pa is equal to or higher than the predetermined pressure Pref is satisfied, the intermittent stopping of the engine 22 may be prohibited regardless of the oil temperature Toil.

[0032] The hybrid vehicle 20 of the embodiment is equipped with a six-speed automatic transmission 45. However, it may be equipped with a four-speed, five-speed, eight-speed, or other automatic transmission.

[0033] The hybrid vehicle 20 of the embodiment includes the engine ECU 24, the motor ECU 34, and the HVECU 70. However, at least two of these may be integrated into one unit.

[0034] In the hybrid vehicle 20 of the embodiment, the engine 22, the motor 30, the inverter 32, the clutch K0, the automatic transmission 40 having the torque converter 43 and the automatic transmission 45, and the high-voltage battery 60 are included. However, the present invention is not limited to this, and any hybrid vehicle may be included as long as it includes an engine, a motor, and a transmission whose input shaft is connected to the engine and the motor and whose output shaft is connected to the drive wheels. For example, as shown in a modified hybrid vehicle 120 of FIG. 3, the hybrid vehicle may be included in addition to the engine 22, the motor 30, the inverter 32, the automatic transmission 45, and the high-voltage battery 60, a planetary gear 122, a motor 130, and an inverter 132. Here, the engine 22, the motor 130, the transmission input shaft 44, and the motor 30 are connected to the carrier, the sun gear, and the ring gear of the planetary gear 122, respectively. The inverter 132 is used to drive the motor 130 and is connected to the high-voltage power line 61 together with the inverter 32 and the high-voltage battery 60 .

[0035] The relationship between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be described below. In the embodiment, the engine 22 corresponds to the "engine", the motor 30 corresponds to the "motor", and the HVECU 70, the engine ECU 24, and the motor ECU 34 correspond to the "control device".

[0036] The correspondence between the main elements of the Examples and the main elements of the invention described in the Summary of the Problem column does not limit the elements of the invention described in the Summary of the Problem column, since the Examples are examples for specifically explaining the mode for implementing the invention described in the Summary of the Problem column. In other words, the interpretation of the invention described in the Summary of the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Summary of the Problem column.

[0037] Although the form for carrying out the present invention has been described above using examples, the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the gist of the present invention. [Industrial Applicability]

[0038] The present invention can be used in the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0039] 20 Hybrid vehicle, 22 Engine, 23 Crankshaft, 23a Crank position sensor, 24 Engine ECU, 25 Starter motor, 26 Alternator, 30 Motor, 30a Rotational position sensor, 31 Rotating shaft, 32 Inverter, 34 Motor ECU, 40 Automatic transmission, 41 Input shaft, 41a RPM sensor, 42 Output shaft, 42a RPM sensor, 43 Torque converter, 44 Transmission input shaft, 44a RPM sensor, 45 Automatic transmission, 46 Oil pan, 47 Oil temperature sensor, 48 Differential gear, 49 Drive wheel, 60 High voltage battery, 61 High voltage side power line, 62 Low voltage battery, 63 Low voltage side power line, 64 DC / DC converter, 70 HVECU, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 87 vehicle speed sensor, 88 atmospheric pressure sensor, 120 hybrid vehicle, 122 planetary gear, 130 motor, 132 inverter.

Claims

1. A hybrid vehicle including an engine, a motor capable of outputting power for driving, and a control device that controls the engine and the motor so as to drive with intermittent operation of the engine, the control device controls the engine and the motor so as to crank the engine by the motor at the start of the engine during the intermittent operation of the engine; The control device prohibits intermittent stopping of the engine when an atmospheric pressure condition is established in which the atmospheric pressure is equal to or higher than a predetermined pressure. A hybrid vehicle characterized by

2. 2. The hybrid vehicle according to claim 1, the control device prohibits intermittent stopping of the engine when an oil temperature condition is satisfied in which a temperature of hydraulic oil lubricating the engine is equal to or lower than a predetermined temperature in addition to the atmospheric pressure condition being satisfied. Hybrid car.

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