Working Machine

• US 20130213020A1
• Filed: 08/24/2011
• Published: 08/22/2013
• Est. Priority Date: 08/31/2010
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Ishikawa, Kouji, Satake, Hidetoshi, Nishikawa, Shinji, Ooki, Takatoshi
• Granted Patent: US 9,010,088 B2
• Time in Patent Office: Days
• US Class Current: 60/311
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 20/16 for reducing engine exhaust emissions
• CPC Class Codes: B60W 2300/17 Construction vehicles, e.g. graders, excavators
• CPC Class Codes: B60W 2710/0694 Engine exhaust temperature
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/1088 pressure of working fluid
• CPC Class Codes: B60Y 2300/476 Regeneration of particle filters
• CPC Class Codes: E02F 9/2066 of the type combustion engines
• CPC Class Codes: E02F 9/2095 Control of electric, electro-mechanical or mechanical equipment not otherwise provided for, e.g. ventilators, electro-driven fans control of hydraulic driven equipment E02F9/22
• CPC Class Codes: E02F 9/2235 including an electronic controller
• CPC Class Codes: F01N 2900/10 said parameters being related to the vehicle or its components
• CPC Class Codes: F01N 2900/1606 Particle filter loading or soot amount
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: F02D 2041/026 using an external load, e.g. by increasing generator load or by changing the gear ratio
• CPC Class Codes: F02D 2200/0812 Particle filter loading
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18
• CPC Class Codes: F02D 41/029 : the exhaust gas treating apparatus being a particulate filter
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor

Abstract

A load application means, which applies a load to an engine such that a temperature of exhaust gas is raised to a temperature required to burn particulate matter, is comprised of an electric load application means for applying the load to the engine to raise the temperature of the exhaust gas by operating an electric assist motor to generate electric power and a hydraulic load application means for applying the load to the engine to raise the temperature of the exhaust gas by increasing a delivery pressure of a variable displacement hydraulic pump, and a selection control unit is provided for performing control processing to selectively actuate the electric load application means and/or the hydraulic load application means.

Claims

1. A working machine, comprising:

an engine, a variable displacement hydraulic pump drivable by the engine, an electric assist motor for assisting the engine in driving the variable displacement hydraulic pump or generating electric power, an exhaust gas purification system for trapping, by a filter, particulate matter in exhaust gas produced from the engine, an actuator control valve interposed between the variable displacement hydraulic pump and the hydraulic actuator and switchable to one of a feed state in which hydraulic oil from the variable displacement hydraulic pump is to be fed to the hydraulic actuator and a non-feed state in which the hydraulic oil is returned to a hydraulic oil reservoir without feeding the hydraulic oil to the hydraulic actuator, an electrical storage device connected to the electrical assist motor, and a load application means for applying a load to the engine such that a temperature of the exhaust gas is raised to a temperature required to burn the particulate matter, wherein;

the load application means comprises an electric load application means for applying the load to the engine to raise the temperature of the exhaust gas by operating the electric assist motor to generate electric power and a hydraulic load application means for applying the load to the engine to raise the temperature of the exhaust gas by increasing a delivery pressure of the variable displacement hydraulic pump, and

the working machine is further provided with a selection control unit for performing control processing to selectively actuate the electric load application means and/or the hydraulic load application means.

2. The working machine according to claim 1, wherein the selection control unit comprises an abnormality monitoring unit for monitoring an abnormality of the electrical drive control system including the electric assist motor and electrical storage device, and, when the abnormality is monitored by the abnormality monitoring unit, performs control processing to actuate the hydraulic load application means.

3. The working machine according to claim 2, wherein the selection control unit comprises a storage state monitoring unit for monitoring a storage state of the electrical storage device, and according to the storage state monitored by the storage state monitoring unit, performs one of control processing that actuates the hydraulic load application means alone, control processing that actuates the electric load application means alone, and control processing that actuates both of the hydraulic load application means and electric load application means.

4. The working machine according to claim 3, wherein upon application of the load to the engine, the selection control unit performs the control processing, in which the hydraulic load application means alone is actuated, when a remaining storage level of the electrical storage device as monitored by the storage state monitoring unit is lower than a preset lower limit threshold value, the control processing, in which the electric load application means alone is actuated, when the remaining storage level of the electrical storage device is higher than a preset higher limit threshold value, or the control processing, in which both of the hydraulic load application means and electric load application means are actuated, when the remaining storage level of the electrical storage device is between the higher limit threshold value and the lower limit threshold value.

5. The working machine according to claim 4, wherein, upon the control processing in which both of the hydraulic load application means and electric load application means are actuated, the selection control unit performs, according to a storage voltage of the electrical storage device, control processing that changes actuation rates of the hydraulic load application means and electric load application means.

6. The working machine according to claim 5, wherein, upon the control processing in which both of the hydraulic load application means and electric load application means are actuated, the selection control unit performs control processing that increases the application rate of the electric load application means when the storage voltage of the electrical storage device is around the lower limit threshold value but increases the application rate of the hydraulic load application means when the storage voltage of the electrical storage device is around the higher limit threshold value.

7. The working machine according to claim 1, further comprising:

a temperature sensor for detecting the temperature of the exhaust gas,

an exhaust gas temperature determination unit for determining whether or not the temperature of the exhaust gas as detected by the temperature sensor is a temperature in a preset temperature range which can be considered to be minimum required to burn the particulate matter, and

an adjustment unit for adjusting the actuation of the load application means, which is selected by the selection control means, such that the temperature of the exhaust gas becomes a temperature in the temperature range when the temperature of the exhaust gas as detected by the temperature sensor is determined not to be a temperature in the temperature range by the exhaust gas temperature determination unit.