Control system for hybrid vehicles

Abstract

The present invention provides a control device for hybrid vehicles that can prevent excessive restriction of engine output. [Solution] A control device for a hybrid vehicle comprising an engine driven by the supply of alcohol-containing fuel, a generator that generates electricity corresponding to the reaction torque and rotational speed by outputting a reaction torque, a differential mechanism that connects the engine, generator, and output members connected to the drive wheels so as to be differentially rotatable, and a power storage device that is charged by the electricity generated by the generator, wherein the control device is configured to perform fuel cut control that stops the supply of fuel to the engine when the power generated by the generator exceeds a determination threshold, and the determination threshold is set to a smaller value the higher the alcohol concentration detected by the concentration detection unit.

Description

Technical Field

[0001] This invention relates to a control device for a hybrid vehicle configured such that an engine, a generator, and drive wheels are connected via a differential mechanism, and the engine speed is controlled by the reaction torque of the generator.

Background Art

[0002] Patent Document 1 describes a control device for a hybrid vehicle in which an engine, a first motor, and an output gear are connected to a planetary gear mechanism, and a second motor is connected to a gear train unit that transmits torque from the output gear to drive wheels. This control device is configured to control the engine and the first motor so that when the engine is rapidly decelerated from a state of rotating at a high speed, the first motor and the pinion gear constituting the planetary gear mechanism do not exceed the upper limit rotational speed. Specifically, when rapid deceleration is detected, fuel cut control is executed, the upper limit rotational speeds of the first motor and the pinion gear are decreased, and further, the gain of the feedback control of the first motor is increased. The fuel cut control is configured to be executed when the actual charging power exceeds a value obtained by adding a predetermined power to the charging power limit value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The control device described in Patent Document 1 is configured so that the engine, the first motor, and the output gear rotate differentially. Therefore, in the event of rapid deceleration, the rotational speed of the first motor increases, and consequently, the power generated by the first motor increases. The power generated by the first motor is equal to the product of the rotational speed of the first motor and the output torque in the direction that reduces the rotational speed. Therefore, by executing fuel cut control when the actual charging power of the first motor exceeds a value obtained by adding a predetermined power to the charging power limit, the output torque of the first motor can be reduced, and the actual charging power can be reduced. Since there is an unavoidable delay between the execution of this fuel cut control and the cessation of fuel supply to the engine, it is considered that the predetermined power is set taking this delay into account.

[0005] On the other hand, in the case of engines that use fuels containing alcohol such as ethanol, the engine's output torque changes depending on the alcohol content (percentage). Therefore, when using fuel with a high alcohol content, the torque output by the engine is large during the process from when the fuel cut control is executed until the fuel supply to the engine stops. This can lead to a relatively large amount of power generated by the first motor, potentially causing the energy storage device to overcharge. Furthermore, if the engine output is limited in advance, assuming a high alcohol content, in order to prevent such overcharging of the energy storage device, the maximum torque of the engine will also be limited even when the alcohol content is relatively low, potentially excessively limiting the maximum driving force of the vehicle.

[0006] This invention was made in view of the above-mentioned technical problems, and aims to provide a control device for a hybrid vehicle that can suppress excessive restriction of engine output. [Means for solving the problem]

[0007] To achieve the above objective, this invention provides a control device for a hybrid vehicle comprising: an engine driven by being supplied with an alcohol-containing fuel; a generator that outputs a reaction torque to generate electricity corresponding to the reaction torque and rotational speed; a differential mechanism that connects the engine, the generator, and an output member connected to the drive wheels so as to be differentially rotatable; and a power storage device that is charged by being supplied with electricity generated by the generator, the control device further comprising: a controller for controlling the engine; and a concentration detection unit for detecting the alcohol concentration, which is the amount of alcohol relative to the amount of fuel supplied to the engine, wherein the controller is configured to perform fuel cut control to stop the supply of fuel to the engine when the power generated by the generator exceeds a predetermined determination threshold, and the determination threshold is set to a smaller value the higher the alcohol concentration detected by the concentration detection unit. [Effects of the Invention]

[0008] According to this invention, since the engine, generator, and output member connected to the drive wheels are differentially rotatable, the engine's torque can be transmitted to the drive wheels by outputting a reaction torque from the generator corresponding to the engine's output torque. The generator also generates electricity according to the reaction torque and its rotational speed. Therefore, when the rotational speed of the drive wheels decreases rapidly due to sudden deceleration, etc., and the rotational speed of the generator increases at a relatively large predetermined rate of change, the power generated by the generator increases in proportion to the increase in rotational speed. When the power generated by the generator increases in this way, the reaction torque of the generator can be reduced by stopping the fuel supply to the engine, thereby preventing an excessive increase in the power generated by the generator.

[0009] Furthermore, since the engine is supplied with fuel containing alcohol, the higher the amount of alcohol in the fuel, the higher the engine's output torque and the greater the generator's reaction torque. Therefore, the system is equipped with a concentration detection unit that detects the alcohol concentration of the fuel supplied to the engine, and the higher the alcohol concentration detected by the concentration detection unit, the smaller the threshold value for executing fuel cut control is set. Consequently, when the rotational speed of the generator increases at a relatively large predetermined rate due to a rapid decrease in the rotational speed of the drive wheels, such as during sudden deceleration, the power generated by the generator can be reduced early. As a result, it is possible to prevent the power generated from exceeding the upper limit of the energy storage device's charging power during the process in which the generator's rotational speed reaches a rotational speed corresponding to the rotational speed of the drive wheels and the engine. In other words, it is not necessary to limit the engine's output torque in advance by assuming a high alcohol concentration, and it is possible to prevent the maximum driving force of the vehicle from being excessively limited. [Brief explanation of the drawing]

[0010] [Figure 1] This is a skeleton diagram illustrating an example of a hybrid vehicle according to an embodiment of this invention. [Figure 2] This is a diagram illustrating the change in the engine's maximum torque depending on the alcohol concentration. [Figure 3] This is a collinear diagram illustrating the changes in rotational speed of each rotating element that constitutes the power split mechanism. [Figure 4] This is a block diagram illustrating a control example that sets the fuel cut-off control initiation power according to the alcohol concentration. [Figure 5] This is a map for setting correction factors according to alcohol concentration. [Figure 6] This is a time chart showing the changes in engine speed, the rotational speed of the first motor, the voltage applied to the energy storage device, the power input to the energy storage device, and the changes in the fuel cut control execution flag when the fuel cut control initiation power is set. [Modes for carrying out the invention]

[0011] This invention will be described based on the embodiments shown in the figures. Note that the embodiments described below are merely examples of how the present invention can be implemented and do not limit the invention.

[0012] Figure 1 shows a skeleton diagram illustrating an example of a hybrid vehicle according to an embodiment of the present invention. The hybrid vehicle Ve shown in Figure 1 (hereinafter simply referred to as "vehicle") is equipped with an engine (ENG) 1, a first motor (MG) 2, and a second motor (not shown) as power sources.

[0013] This engine 1 is configured to generate power by burning a mixture of air and fuel, similar to engines used as a power source in conventional engine vehicles and hybrid vehicles. As this fuel, an alcohol-containing fuel, such as ethanol mixed with gasoline, can be used.

[0014] Because alcohol-containing fuels have a higher octane rating compared to regular gasoline or diesel, they produce a higher maximum torque. Figure 2 shows the maximum torque of engine 1 for each alcohol concentration, which is the alcohol content relative to the amount of fuel supplied to engine 1. In Figure 2, the horizontal axis represents engine speed, and the vertical axis represents engine torque.

[0015] As shown in Figure 2, similar to conventional gasoline and diesel fuels, regardless of the alcohol concentration, the maximum torque of engine 1 increases with increasing engine speed until the engine speed reaches a predetermined speed. Once the engine speed exceeds the predetermined speed, the maximum torque of engine 1 decreases with increasing engine speed. Furthermore, regardless of the engine speed of engine 1, the higher the alcohol concentration, the greater the maximum torque.

[0016] As described above, since the maximum torque of the engine 1 changes depending on the alcohol concentration, a concentration sensor 3 for detecting the alcohol concentration of the fuel is provided, for example, in a fuel tank or a fuel delivery pipe (not shown). This concentration sensor 3 corresponds to the "concentration detection unit" in the embodiment of this invention. In addition, the engine 1 is provided with a crank angle sensor 4 for detecting its rotational speed (or rotational angle).

[0017] The first motor 2 and the second motor can be configured in the same manner as the motors provided as driving power sources in conventional hybrid vehicles and electric vehicles. That is, in addition to the function as a motor that outputs driving torque when power is supplied, it has a function as a generator that converts the power of its output shaft into electric power when the output shaft is rotated. Specifically, it can be configured by a permanent magnet type synchronous motor or an induction motor. This first motor 2 corresponds to the "generator" in the embodiment of this invention. In addition, each motor 2 is provided with a resolver 5 for detecting its rotational angle.

[0018] In addition, the first motor 2 and the second motor are connected to a power control unit (hereinafter referred to as PCU) 6 composed of electronic components such as an inverter (not shown) to a power storage device 7. This power storage device 7 is a power source that outputs a DC voltage, similar to the power sources provided in conventional electric vehicles and hybrid vehicles, and can be configured by a secondary battery such as a lithium ion battery or a nickel hydrogen battery, or an electric double layer capacitor. This power storage device 7 may be configured by a battery pack in which a plurality of batteries are arranged in series.

[0019] Therefore, by controlling the PCU 6 to supply power from the power storage device 7 to the first motor 2 and the second motor, the first motor 2 and the second motor function as motors that output driving torque (torque that increases the rotational speed). Also, when the first motor 2 and the second motor function as generators that generate electric power when they are rotated, the electric power can be charged to the power storage device 7.

[0020] Since the internal resistance of the above-described power storage device 7 varies according to its temperature, when the temperature of the power storage device 7 is low, a large current flows through the power storage device 7. Therefore, the allowable discharge power output from the power storage device 7 and the allowable charge power for charging the power storage device 7 are configured to be limited according to the temperature of the power storage device 7. For this reason, as shown in FIG. 1, the power storage device 7 is provided with a temperature sensor 8 for detecting its temperature, and an ammeter 9 for detecting the current value supplied to each motor 2 is provided between each motor 2 and the PCU 6. Note that a voltmeter 10 for detecting the voltage output from the power storage device 7 or the voltage applied to the power storage device 7 is provided between the power storage device 7 and the PCU 6.

[0021] Also, as shown in FIG. 1, the vehicle Ve is provided with a power split mechanism 11 that splits the output torque of the engine 1 between the first motor 2 and the drive wheels (not shown). This power split mechanism 11 is a differential mechanism in which the engine 1, the first motor 2, and the drive wheels are connected so as to be differentially rotatable. In the example shown in FIG. 1, it is constituted by a single pinion type planetary gear mechanism. That is, it is constituted by a sun gear S, a ring gear R arranged concentrically with the sun gear S, and a carrier C that holds a pinion gear P that meshes with the sun gear S and the ring gear R so as to be rotatable and revolvable. The first motor 2 is connected to the sun gear S, the engine 1 is connected to the carrier C, and an output gear 12 for transmitting torque to the drive wheels is connected to the ring gear R. This output gear 12 corresponds to the "output member" in the embodiment of this invention.

[0022] Note that a gear train portion (not shown) for transmitting torque from the ring gear R to the drive wheels is provided, and a second motor is connected to the gear train portion so as to be torque-transmittable. That is, it is configured such that the torque output from the second motor can be added to the torque transmitted from the engine l to the gear train portion via the power split mechanism 11. The second motor is configured to be supplied with the power charged in the power storage device 7 and the power generated by the first motor 2.

[0023] A controller 13 is provided for controlling the engine 1 and each motor 2 (specifically, each PCU 6) as described above. Similar to controllers installed in conventional vehicles, this controller 13 is mainly composed of a microcomputer and is configured to generate and output command signals for controlling the engine 1 and each motor 2 based on input signals and pre-stored calculation formulas and maps.

[0024] The signals input to the controller 13 include those from the concentration sensor 3, crank angle sensor 4, resolver 5, temperature sensor 8, ammeter 9, voltmeter 10, accelerator opening sensor 14 for detecting the amount of accelerator operation by the driver, wheel speed sensor 15 for detecting the rotational speed of the drive wheels, and SOC sensor 16 for detecting the remaining charge of the energy storage device 7.

[0025] The controller 13 determines the required driving power for the vehicle Ve based on the signal detected by the accelerator opening sensor 14 and the signal detected by the wheel speed sensor 15. It also determines the required charging power (hereinafter referred to as charging power) to charge the energy storage device 7 based on the signal detected by the SOC sensor 16. If the remaining charge of the energy storage device 7 is above the upper limit, the charging power is calculated as a negative value. The power required for the engine 1 (hereinafter referred to as required engine power) is then determined by adding the driving power and the charging power.

[0026] The operating point of engine 1 that provides good fuel efficiency when outputting the above-mentioned required engine power is determined. This operating point of engine 1 is determined by the output torque and rotational speed of engine 1, and an optimal fuel efficiency curve map, which has been constructed by determining the operating point that provides good fuel efficiency for each engine power through experiments and simulations, is stored in the controller 13. Therefore, the operating point of engine 1 is determined based on the required engine power and the optimal fuel efficiency curve map.

[0027] Figure 3 shows a collinear diagram illustrating the change in rotational speed of each rotating element constituting the power split mechanism 11. The state in which the vehicle Ve is driven at a predetermined speed is shown by a dashed line, and the state in which it is being suddenly braked is shown by a solid line.

[0028] In the power split mechanism 11, the sun gear S is connected to the first motor 2, so the rotational speed of the sun gear S is the same as the rotational speed of the first motor 2. Similarly, the carrier C is connected to the engine 1, so the rotational speed of the carrier C is the same as the rotational speed of the engine 1. Furthermore, the ring gear R is connected to the drive wheels via the output gear 12 and the gear train, so the rotational speed of the ring gear R is obtained by dividing the rotational speed of the drive wheels by the gear ratio of the gear train. For convenience, Figure 3 shows the gear ratio of the gear train as "1," so the rotational speed of the ring gear R and the rotational speed of the drive wheels are shown as being the same.

[0029] As shown in Figure 3, when the vehicle is driving at a predetermined speed, engine 1 is controlled to achieve the rotational speed and torque determined based on the required engine power and optimal fuel efficiency curve map described above. The direction of engine torque is indicated by a dashed arrow.

[0030] Furthermore, the reaction torque of the first motor 2 is determined so that engine torque is output via the power split mechanism 11. This reaction torque is set to be the same magnitude as the torque transmitted from the engine 1 to the first motor 2 according to the gear ratio of the power split mechanism 11. Note that by outputting a torque greater than the torque transmitted from the engine 1 to the first motor 2, the engine speed decreases, and conversely, by outputting a torque smaller than the torque transmitted from the engine 1 to the first motor 2, the engine speed increases and the torque transmitted to the output gear 12 decreases. In other words, the target torque of the first motor 2 is determined by adding a feedback torque to reduce the difference between the rotational speed of the first motor 2 required to achieve the target engine speed and the actual rotational speed of the first motor 2 to the reference reaction torque obtained by multiplying the required torque of the engine 1 by the gear ratio of the power split mechanism 11. The direction of the reaction torque of the first motor 2 is indicated by a dashed arrow.

[0031] As described above, when the vehicle is traveling at a predetermined speed, if the rotational speed of the drive wheels suddenly decreases due to the brake pedal being pressed or other reasons, the rotational speed of the first motor 2 increases rapidly while maintaining or almost completely changing the rotational speed of the engine 1, as shown by the solid line in Figure 3. This is because the engine 1 is outputting drive torque due to factors such as an unavoidable delay between the decrease in the torque required by the engine 1 and the decrease in the output of the engine 1.

[0032] When the rotational speed of the first motor 2 increases in this manner, the engine 1 continues to output driving torque, causing the first motor 2 to output a torque that is the sum of a reference reaction torque corresponding to the driving torque and a feedback torque associated with the increase in rotational speed. As a result, the first motor 2 generates power calculated by multiplying its reaction torque by the rotational speed. The reference reaction torque may be an estimated value of the driving torque of the engine 1.

[0033] The control device in this embodiment of the invention is configured to prevent the power generated by the first motor 2 from exceeding the power (Win) that can be supplied to the energy storage device 7 when the rotational speed of the first motor 2 increases rapidly as described above.

[0034] Figure 4 shows a block diagram illustrating the functional configuration of the control example. The example shown in Figure 4 includes an actual power acquisition unit 17, a charge allowable power acquisition unit 18, an over-determination threshold acquisition unit 19, a correction coefficient calculation unit 20, a multiplier 21, a subtractor 22, a comparison unit 23, and an output unit 24.

[0035] The actual power acquisition unit 17 is configured to acquire the power generated by the first motor 2 by detecting the current value between the first motor 2 and the PCU 6 using the ammeter 10. This actual power acquisition unit 17 acquires the power generated by the first motor 2 as a negative value.

[0036] The charge-permitted power acquisition unit 18 is configured to acquire the power that can be charged to the energy storage device 7. This power that can be charged to the energy storage device 7 (hereinafter referred to as charge-permitted power) is the power that can be continuously input to the energy storage device 7 and is predetermined by the rating, etc. Here, the charge-permitted power is calculated as a negative value. As mentioned above, the internal resistance of the energy storage device 7 fluctuates according to the temperature of the energy storage device 7, and the charge-permitted power fluctuates accordingly. Therefore, the charge-permitted power acquisition unit 18 may obtain the charge-permitted power by multiplying the charge-permitted power, which is stored in advance in the controller 13, by a coefficient corresponding to the temperature detected by the temperature sensor 8.

[0037] The over-determination threshold acquisition unit 19 acquires a reference determination threshold for initiating fuel cut control when the power generated by the first motor 2 does not exceed a predetermined upper limit of power that can be temporarily exceeded, based on the rating of the energy storage device 7, etc. This reference determination threshold is defined as the power exceeding the allowable charging power. Here, the reference determination threshold is acquired as a positive value.

[0038] The correction coefficient calculation unit 20 is configured to calculate a coefficient corresponding to the alcohol concentration of the fuel based on the map shown in Figure 5. This map shown in Figure 5 is pre-constructed through experiments and simulations and stored in the controller 13. When the alcohol concentration is below a predetermined concentration, the coefficient is set to "1," and when the alcohol concentration is above the predetermined concentration, the coefficient gradually decreases in value according to the alcohol concentration.

[0039] The multiplier 21 multiplies the reference judgment threshold obtained by the over-judgment threshold acquisition unit 19 by the coefficient calculated by the correction coefficient calculation unit 20. In other words, it corrects the judgment threshold for initiating fuel cut control according to the alcohol concentration. Therefore, the higher the alcohol concentration, the smaller the judgment threshold obtained by the multiplier 21 becomes.

[0040] The subtractor 22 subtracts the determination threshold obtained by the multiplier 21 from the charge-permitted power acquired by the charge-permitted power acquisition unit 18. In other words, it determines the fuel cut control start power at which fuel cut control is initiated. This fuel cut control start power corresponds to the "determination threshold" in this embodiment of the invention.

[0041] Then, the power generated by the first motor 2, acquired by the actual power acquisition unit 17, is compared with the fuel cut control start power determined by the subtractor to determine whether the power generated exceeds the fuel cut control start power. Based on this determination, the output unit 24 outputs a command signal to the injector of the engine 1.

[0042] Figure 6 shows a time chart illustrating the changes in engine speed, the rotational speed of the first motor 2 (MG rotational speed), the voltage applied to the energy storage device 7, the power input to the energy storage device 7, and the fuel cut control execution flag when the vehicle suddenly decelerates and stops from a state of traveling at a predetermined vehicle speed. The changes in behavior when the fuel cut control initiation power is determined according to the alcohol concentration are shown by a solid line, and the changes in behavior when the fuel cut control initiation power is not changed are shown by a dashed line.

[0043] At time t0 shown in Figure 6, the vehicle is driven at a predetermined speed, so the wheel speed, engine speed, and the rotational speed of the first motor 2 are kept constant. At the same time, the engine 1 outputs a driving torque, and the first motor 2 outputs a reaction torque corresponding to the torque transmitted from the engine 1. The rotational speed of the engine 1 matches the target rotational speed, and therefore the feedback torque of the first motor 2 is effectively zero. As a result, the first motor 2 generates a predetermined amount of power, and a predetermined voltage is applied to the energy storage device 7 accordingly. In Figure 6, the generated power is shown as a negative value.

[0044] At time t1, braking torque is applied to the drive wheels due to braking by the driver, and as a result, the wheel speed begins to decrease. As mentioned above, there is an unavoidable delay between the decrease in the required torque of engine 1 and the decrease in the output of engine 1. Because driving torque is output from engine 1, the engine speed is maintained, and the rotational speed of the first motor 2 increases. The amount of increase in the rotational speed of the first motor 2 is determined according to the engine speed and the gear ratio of the power split mechanism 11.

[0045] Furthermore, even while the rotational speed of the first motor 2 is increasing, torque is output from the engine 1, causing the first motor 2 to output a reference reaction torque corresponding to the output torque of the engine 1. In addition, as the rotational speed of the first motor 2 increases, the target rotational speed and the actual rotational speed diverge, and a feedback torque corresponding to this difference is output from the first motor 2. As a result, the generation of electricity by the first motor 2 increases the generated power and the voltage applied to the energy storage device 7 in proportion to the rotational speed of the first motor 2.

[0046] As the power generated by the first motor 2 increases in this way, at time t2, it exceeds the power required to initiate fuel cut control, which is determined according to the alcohol concentration. Consequently, fuel cut control is initiated, and the output torque of engine 1 gradually decreases. As a result, the reference reaction torque in the first motor 2 decreases, causing the torque of the first motor 2 to decrease. Consequently, although the rotational speed of the first motor 2 continues to increase after time t2, the power generated by the first motor 2 gradually decreases.

[0047] On the other hand, as shown by the dashed line in Figure 6, if the fuel cut control initiation power is not determined according to the alcohol concentration, that is, if fuel cut control is performed based on the reference judgment threshold acquired by the excess judgment threshold acquisition unit 19 described above, fuel cut control is started at time t3. Therefore, the power generated by the first motor 2 is increased due to the delay in the timing of starting fuel cut control. Even if fuel cut control is started, there is an unavoidable delay after the start is determined, so the power generated by the first motor 2 increases for a predetermined period from time t2 or t3, and then decreases thereafter.

[0048] At time t4, when the vehicle stops, the rotational speed of the first motor 2 reaches its maximum speed, and thereafter, the first motor 2 outputs torque to reduce the engine speed to an idle speed. In other words, the torque output from the first motor 2 is only feedback torque, and it outputs torque corresponding to the idle speed of the engine 1 and the first motor 2. As a result, the engine speed and the rotational speed of the first motor 2 begin to decrease. Along with the decrease in the rotational speed of the first motor 2, the power generated by the first motor 2 and the voltage applied to the energy storage device 7 begin to decrease. In the example shown in Figure 6, at time t5, the flag for executing fuel cut control is switched off because the engine speed has decreased to an idle speed. Note that the flag for executing fuel cut control may also be switched off based on other parameters such as the power generated by the first motor 2.

[0049] As described above, since the engine 1, the first motor 2, and the drive wheels are connected to the power split mechanism 11, a sudden decrease in the rotational speed of the drive wheels due to rapid deceleration, etc., causes the rotational speed of the first motor 2 to increase, and the generated power increases with the increase in rotational speed. The torque of the first motor 2 is determined by a reference reaction torque corresponding to the output torque of the engine 1 and a feedback torque corresponding to the difference between the target rotational speed and the actual rotational speed of the first motor 2. Therefore, when the generated power of the first motor 2 increases, fuel cut control is performed to stop the supply of fuel to the engine 1, thereby reducing the reaction torque of the first motor 2 and preventing an excessive increase in the generated power of the first motor 2.

[0050] Furthermore, since the engine 1 is supplied with fuel containing alcohol, the higher the amount of alcohol contained in the fuel, the higher the output torque of the engine 1 and the greater the reaction torque of the first motor 2. For this reason, the engine 1 is equipped with a concentration sensor 3 that detects the alcohol concentration of the fuel supplied to it, and the higher the alcohol concentration detected by the concentration sensor 3, the smaller the fuel cut control initiation power set to start the fuel cut control. Therefore, when the rotational speed of the first motor 2 increases at a relatively large rate of change due to a rapid decrease in the rotational speed of the drive wheels, such as during sudden deceleration, the power generated by the first motor 2 can be reduced early. As a result, it is possible to prevent the power generated from exceeding the upper limit of the charging power of the energy storage device 7 during the process in which the rotational speed of the first motor 2 reaches a rotational speed corresponding to the rotational speed of the drive wheels and the engine rotational speed. In other words, it is not necessary to limit the output torque of the engine 1 in advance assuming a high alcohol concentration, and it is possible to prevent the maximum driving force of the vehicle Ve from being excessively limited. [Explanation of symbols]

[0051] 1 Engine 2 motors 3. Diffusion Sensor 7. Energy storage device 8. Temperature sensor 11 Power split mechanism 12 Output gears 13 Controllers 15 Wheel speed sensor 17. Actual Power Acquisition Unit 18. Unit for obtaining charge allowable power 19. Unit for obtaining the threshold for exceeding the threshold 20 Correction coefficient calculation unit 21 Multiplier 22 Subtractors 23 Comparison Section 24 Output section C Carrier P pinion gear R Ring Gear S Sangiya Vehicle

Claims

[Claim 1] A control device for a hybrid vehicle comprising: an engine driven by the supply of alcohol-containing fuel; a generator that outputs a reaction torque to generate electricity corresponding to the reaction torque and rotational speed; a differential mechanism that connects the engine, the generator, and an output member connected to the drive wheels so as to be differentially rotatable; and a power storage device that is charged by the electricity generated by the generator, A controller that controls the engine, The system further includes a concentration detection unit that detects the alcohol concentration, which is the amount of alcohol in relation to the amount of fuel supplied to the engine. The aforementioned controller, The system is configured to perform fuel cut control, which stops the supply of fuel to the engine, when the power generated by the generator exceeds a predetermined threshold. The higher the alcohol concentration detected by the concentration detection unit, the smaller the judgment threshold value is set. A control device for a hybrid vehicle characterized by the following features.

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