# US 10,245,958 B2 · Hybrid vehicle and control method therefor

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- Number: US 10,245,958 B2
- Document ID: US10245958B2
- Status: Granted
- Kind: B2
- Application number: 15/922,319
- Filed: 2018-03-15
- Published: 2018-09-20
- Granted: 2019-04-02
- Earliest claimed: 2017-03-17
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Daiki Takayama
- Web page: https://patentgrep.com/patent/US10245958B2

## CPC

- B60L 50/16: with provision for separate direct mechanical propulsion
- B60K 6/445: Differential gearing distribution type
- B60L 3/003: {relating to inverters}
- B60L 3/0046: {relating to electric energy storage systems, e.g. batteries or capacitors}
- B60L 7/14: for vehicles propelled by AC motors
- B60L 15/007: {Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles}
- B60W 10/06: including control of combustion engines
- B60W 10/08: including control of electric propulsion units, e.g. motors or generators
- B60W 10/30: including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
- B60W 20/15: Control strategies specially adapted for achieving a particular effect
- B60L 2210/42: Voltage source inverters
- B60L 2220/14: Synchronous machines
- B60L 2240/423: Torque
- B60L 2240/547: Voltage
- B60L 2240/549: Current
- B60W 2510/081: Speed
- B60W 2520/10: Longitudinal speed
- B60W 2710/0644: Engine speed
- Y02T 10/62: Hybrid vehicles
- Y02T 10/64: Electric machine technologies in electromobility
- Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
- Y02T 10/72: Electric energy management in electromobility
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An engine and a step up-down converter are controlled such that a counter-electromotive voltage of a first motor becomes higher than direct current-side voltages of a first inverter and a second inverter and thereby torque for forward travel is output from the first motor to a driving shaft through a planetary gear set, when an accelerator is on during specified travelling with gates of the first inverter and the second inverter being cut off and the engine being operated. The engine and the step up-down converter are controlled such that the rotational speed of the first motor becomes smaller and the voltage of the high voltage-side electric power line becomes lower when the accelerator is off than when the accelerator is on during the specified traveling.

## Claims

### Claim 1

A hybrid vehicle, comprising:
an engine;
a first motor configured to generate a counter-electromotive voltage with rotation of the first motor;
a second motor connected to a driving shaft coupled with driving wheels of the hybrid vehicle, the second motor being configured to generate a counter-electromotive voltage with rotation of the second motor;
a planetary gear set including three rotation elements connected to three shafts, the shafts including a shaft of the first motor, a shaft of the engine, and the driving shaft, the three rotation elements being connected such that the first motor, the engine, and the driving shaft are arrayed in the order of the first motor, the engine, and the driving shaft in an alignment chart;
a first inverter configured to drive the first motor;
a second inverter configured to drive the second motor;
an electric storage device;
a step up-down converter connected to a low voltage-side electric power line and a high voltage-side electric power line, the low voltage-side electric power line being connected to the electric storage device, the high voltage-side electric power line being connected to the first inverter and the second inverter, the step up-down converter being configured to transfer electric power between the low voltage-side electric power line and the high voltage-side electric power line while changing voltage of the electric power; and
an electronic control unit configured to:
(i) control the engine and the step up-down converter such that the counter-electromotive voltage of the first motor becomes higher than a direct current-side voltage of the first inverter and a direct current-side voltage of the second inverter and that torque is output from the first motor to the driving shaft through the planetary gear set, when an accelerator is on during specified traveling of the hybrid vehicle with gates of the first inverter and the second inverter being cut off and the engine being operated, and
(ii) control the engine and the step up-down converter such that rotational speed of the first motor becomes smaller and voltage of the high voltage-side electric power line becomes lower when the accelerator is off than when the accelerator is on during the specified traveling.

### Claim 2 (depends on 1)

The hybrid vehicle according to claim 1, wherein
the electronic control unit is configured to:
(i) set a target voltage of the high voltage-side electric power line such that a total torque of the driving shaft is maximized as braking torque when the accelerator is off during the specified traveling, and
(ii) control the step up-down converter such that the voltage of the high voltage-side electric power line becomes the target voltage.

### Claim 3 (depends on 1)

The hybrid vehicle according to claim 1, wherein
the electronic control unit is configured to:
(i) control the step up-down converter such that the voltage of the high voltage-side electric power line becomes lower than the voltage when the accelerator is on, when the accelerator is off during the specified traveling and when vehicle speed is in a specified range, and
(ii) control the step up-down converter such that the voltage of the high voltage-side electric power line becomes identical to the voltage when the accelerator is on, when the vehicle speed is out of the specified range.

### Claim 4 (depends on 3)

The hybrid vehicle according to claim 3, wherein
the specified range of the vehicle speed has a lower limit that is a threshold used for determining whether or not the hybrid vehicle is required to secure a braking force of a specified magnitude.

### Claim 5 (depends on 3)

The hybrid vehicle according to claim 3, wherein
the specified range of the vehicle speed has an upper limit that is a threshold used for determining whether or not electric current of a specified value or more possibly flow to the second inverter, the step up-down converter, and the electric storage device, when the voltage of the high voltage-side electric power line is made lower than the voltage when the accelerator is on.

### Claim 6 (depends on 1)

The hybrid vehicle according to claim 1, wherein
the electronic control unit is configured to control the engine such that the engine rotates at an allowable lower limit rotational speed, when the accelerator is off during the specified traveling.

### Claim 7

A control method for a hybrid vehicle, the hybrid vehicle including: an engine, a first motor configured to generate a counter-electromotive voltage with rotation of the first motor; a second motor connected to a driving shaft coupled with driving wheels of the hybrid vehicle, the second motor being configured to generate a counter-electromotive voltage with rotation of the second motor; a planetary gear set including three rotation elements connected to three shafts, the shafts including a shaft of the first motor, a shaft of the engine, and the driving shaft, the three rotation elements being connected such that the first motor, the engine, and the driving shaft are arrayed in the order of the first motor (MG1), the engine, and the driving shaft in an alignment chart; a first inverter configured to drive the first motor; a second inverter configured to drive the second motor; an electric storage device; and a step up-down converter connected to a low voltage-side electric power line and a high voltage-side electric power line, the low voltage-side electric power line being connected to the electric storage device, the high voltage-side electric power line being connected to the first inverter and the second inverter, the step up-down converter being configured to transfer electric power between the low voltage-side electric power line and the high voltage-side electric power line while changing voltage of the electric power, the control method comprising:
(i) controlling the engine and the step up-down converter such that the counter-electromotive voltage of the first motor becomes higher than a direct current-side voltage of the first inverter and a direct current-side voltage of the second inverter and that torque is output from the first motor to the driving shaft through the planetary gear set, when an accelerator is on during specified traveling of the hybrid vehicle with gates of the first inverter and the second inverter being cut off and the engine being operated, and
(ii) controlling the engine and the step up-down converter such that rotational speed of the first motor becomes smaller and voltage of the high voltage-side electric power line becomes lower when the accelerator is off than when the accelerator is on during the specified traveling.