HYBRID WHEEL LOADER

• US 20130151055A1
• Filed: 08/19/2011
• Published: 06/13/2013
• Est. Priority Date: 09/17/2010
• 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, Moriki, Hidekazu, Ito, Noritaka, Yanagimoto, Hiroaki
• Granted Patent: US 8,914,177 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• 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 2300/17 Construction vehicles, e.g. graders, excavators
• CPC Class Codes: B60Y 2200/415 Wheel loaders
• CPC Class Codes: B60Y 2400/114 Super-capacities
• CPC Class Codes: E02F 9/20 Drives; Control devices gearings in general F16H; controlling in general G05; electric multi-motor drives H02K, H02P
• CPC Class Codes: E02F 9/2075 of the hybrid type for vehicles in general B60W20/00
• 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: Y10S 903/907 Electricity storage, e.g. battery, capacitor

Abstract

[Problem] To provide a hybrid wheel loader capable of highly efficient and stable supply of motive power.

[Solution] A hybrid wheel loader including: a front work machine (5) provided at the front of a vehicle; power sources including an engine (1) and an electric storage device; and a hybrid control device (20) which controls output of these power sources; characterized in that: a capacitor (11) is provided as the electric storage device; and the hybrid control device makes control to decrease a voltage of the capacitor in accordance with increase of energy held by the vehicle.

Claims

1. A hybrid wheel loader comprising:

a front work machine provided at the front of a vehicle;

power sources including an engine, a motor/generator and an electric storage device; and

a hybrid control device which controls outputs of the power sources;

characterized in that;

a capacitor is provided as the electric storage device; and

the hybrid control device makes control to decrease a voltage of the capacitor in accordance with increase of energy held by the vehicle.

2. A hybrid wheel loader according to claim 1, characterized in that:

the energy held by the vehicle consists of kinetic energy based on a traveling speed of a vehicle body, or energy obtained by adding at least one of potential energy based on height of a bucket of the front work machine and rotational energy based on rotation speeds of the engine and the motor/generator to the kinetic energy.

3. A hybrid wheel loader according to claim 1, characterized in that:

the hybrid control device makes control to obtain different characteristics in the voltage of the capacitor relative to the energy held by the vehicle between a normal operation mode in which normal work operation is carried out and a vehicle standby mode in which the vehicle is kept standby, while making control to set the voltage of the capacitor at a first specific voltage value which is lower than a maximum service voltage value and higher than a minimum service voltage value when the energy held by the vehicle takes a predetermined low output value in the normal operation mode; and

when the state in which the energy held by the vehicle takes the predetermined low output value is continued for a predetermined period of time, the hybrid control device makes control to rise the voltage of the capacitor from the first specific voltage value to the maximum service voltage value, and to then decrease the rotation speed of the engine to a rotation speed in an idle state to thereby bring the vehicle into the vehicle standby mode.

4. A hybrid wheel loader according to claim 3, characterized in that:

the hybrid control device makes control in the normal operation mode to decrease the voltage of the capacitor from the first specific voltage value to a second specific voltage value, which is higher than the minimum service voltage value and lower than the first specific voltage value, in accordance with increase in the energy held by the vehicle, and makes control in the vehicle standby mode to decrease the voltage of the capacitor from the maximum service voltage value to the minimum service voltage value in accordance with increase in the energy held by the vehicle.

5. A hybrid wheel loader according to claim 1, characterized in that:

the hybrid control device makes control to obtain different characteristics in the voltage of the capacitor relative to the energy held by the vehicle between a normal operation mode in which normal work operation is carried out and a vehicle standby mode in which the vehicle is kept standby, while making control to set the voltage of the capacitor at a first specific voltage value which is lower than a maximum service voltage value and higher than a minimum service voltage value when the energy held by the vehicle takes a predetermined low output value in the normal operation mode; and

when the state in which the energy held by the vehicle takes the predetermined low output value is continued for a predetermined period of time, the hybrid control device makes control to rise the voltage of the capacitor from the first specific voltage value to the maximum service voltage value, and to then decrease the rotation speed of the engine to a rotation speed in an idle state to thereby bring the vehicle into the vehicle standby mode.

6. A hybrid wheel loader according to claim 5, characterized in that:

the hybrid control device makes control in the normal operation mode to decrease the voltage of the capacitor from the first specific voltage value to a second specific voltage value, which is higher than the minimum service voltage value and lower than the first specific voltage value, in accordance with increase in the energy held by the vehicle, and makes control in the vehicle standby mode to decrease the voltage of the capacitor from the maximum service voltage value to the minimum service voltage value in accordance with increase in the energy held by the vehicle.