WORK VEHICLE

• US 20150267380A1
• Filed: 11/06/2013
• Published: 09/24/2015
• Est. Priority Date: 11/07/2012
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Kaneko, Satoru, Ikimi, Takashi, Itou, Noritaka, Moriki, Hidekazu, Takeuchi, Ken
• Granted Patent: US 9,598,838 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 2260/28 Four wheel or all wheel drive
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 20/00 : Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2510/305 : Power absorbed by auxiliaries
• CPC Class Codes: B60W 2710/244 : Charge state
• CPC Class Codes: E02F 9/2079 : Control of mechanical transmission for hydrostatic transmission or hydraulic torque converter E02F9/2253
• CPC Class Codes: E02F 9/2091 : Control of energy storage means for electrical energy, e.g. battery or capacitors energy recovery arrangements in hydraulic or pneumatic drives E02F9/2217
• CPC Class Codes: E02F 9/2221 : Control of flow rate; Load sensing arrangements E02F9/2203 take precedence over E02F9/2221
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 10/92 : Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements

Abstract

There are provided a work vehicle comprising a motor generator (6) driven by an engine, a hydraulic pump (4) driven by at least either of the motor generator and the engine, a work device (50) driven by hydraulic fluid from the hydraulic pump, a electric traction motor (9) driving wheels (61), an electrical storage device (11) connected to the motor generator and to the electric traction motor and charged electrically on the basis of a target SOC; and a control device (200) varying the target SOC for the electrical storage device (11) on the basis of total demanded power (Pf+Prun) of the hydraulic pump and the electric traction motor.

Claims

1. A work vehicle comprising:

a motor generator driven by an engine;

a hydraulic pump driven by at least either of the motor generator and the engine;

a work device driven by hydraulic fluid from the hydraulic pump;

a electric traction motor for driving wheels;

an electrical storage device connected to the motor generator and to the electric traction motor and charged electrically on the basis of a target SOC; and

a control device that varies the target SOC for the electrical storage device on the basis of total demanded power of the hydraulic pump and the electric traction motor.

2. The work vehicle according to claim 1,

wherein the smaller the total demanded power, the higher the target SOC for the electrical storage device is set by the control device.

3. The work vehicle according to claim 1,

wherein, if the total demanded power is smaller than a set value, the control device sets the target SOC for the electrical storage device to be higher than in other cases.

4. The work vehicle according to claim 3,

wherein the control device determines the load condition of the work vehicle to be heavy load, intermediate load, or light load in accordance with the magnitude of the total demanded power, the control device further setting the target SOC for the electrical storage device to be higher if the result of the determination is light load than if the result of the determination is the intermediate load.

5. The work vehicle according to claim 4,

wherein, if the result of the determination is intermediate load, the control device either sets the target SOC for the electrical storage device to be lower than if the result of the determination is the light load or the heavy load, or sets the current SOC of the electrical storage device to the target SOC for the electrical storage device.

6. The work vehicle according to claim 4,

wherein, if the result of the determination is heavy load and if the SOC of the electrical storage device is higher than a lower limit of the range of use of the electrical storage device, the control device sets the target SOC for the electrical storage device to be higher than if the result of the determination is the intermediate load.

7. The work vehicle according to claim 4,

wherein, if the result of the determination is light load, the control device sets the target SOC for the electrical storage device to an upper limit of the range of use of the electrical storage device.

8. The work vehicle according to claim 4, further comprising

a first switching device switching a threshold limit value of the total output of the hydraulic pump and of the electric traction motor either to a first value or to a second value higher than the first value;

wherein, if the result of the determination is intermediate load and if the threshold limit value is switched to the first value by the first switching device, the control device either sets the target SOC for the electrical storage device to be lower than if the result of determination is the light load or the heavy load, or sets the current SOC of the electrical storage device to the target SOC for the electrical storage device; and

wherein, if the result of the determination is intermediate load and if the threshold limit value is switched to the second value by the first switching device, the control device sets the target SOC for the electrical storage device to be higher than if the threshold limit value is switched to the first value.

9. The work vehicle according to claim 4, further comprising

a second switching device having a first position and a second position, the first position being selected to give preference to charging the electrical storage device, the second position being selected not to give preference to the charging;

wherein, if the result of the determination is intermediate load and if the second switching device is set to the first position, the control device either sets the target SOC for the electrical storage device to be lower than if the result of the determination is the light load or the heavy load, or sets the current SOC of the electrical storage device to the target SOC for the electrical storage device; and

wherein, if the result of the determination is intermediate load and if the second switching device is set to the second position, the control device sets the target SOC for the electrical storage device to be higher than if the second switching device is set to the first position.