Work vehicle

• US 9,758,946 B2
• Filed: 02/26/2014
• Issued: 09/12/2017
• Est. Priority Date: 02/26/2014
• Status: Active Grant

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Yogita, Jin, Morinaga, Eiji, Okuda, Kozo, Morimoto, Kazuyoshi
• Primary Examiner(s): Vilakazi, Sizo
• Application Number:
  US14/372,108
• Publication Number:
  US 20150240454A1
• Time in Patent Office: 1,294 Days
• CPC Class Codes: E02F 3/32 working downwardly and towards the machine, e.g. with backhoes
• CPC Class Codes: E02F 9/0866 Engine compartment, e.g. heat exchangers, exhaust filters, cooling devices, silencers, mufflers, position of hydraulic pumps in the engine compartment
• CPC Class Codes: E02F 9/0883 Tanks, e.g. oil tank, urea tank, fuel tank for vehicles in general B60K15/00
• CPC Class Codes: E02F 9/2066 of the type combustion engines
• CPC Class Codes: E02F 9/2235 including an electronic controller
• CPC Class Codes: F01N 11/00 Monitoring or diagnostic devices for exhaust-gas treatment apparatus , e.g. for catalytic activity safety, indicating or supervising devices for internal combustion engines F02B77/08; testing of machines G01M13/00
• CPC Class Codes: F01N 2550/05 Systems for adding substances into exhaust
• CPC Class Codes: F01N 2590/08 for heavy duty applications, e.g. trucks, buses, tractors, locomotives
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]
• CPC Class Codes: F02D 2041/228 Warning displays
• CPC Class Codes: F02D 2200/604 Engine control mode selected by driver, e.g. to manually start particle filter regeneration or to select driving style
• CPC Class Codes: F02D 2250/26 by applying a torque limit
• 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 41/0275 the exhaust gas treating apparatus being a NOx trap or adsorbent
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/2422 Selective use of one or more tables
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A work vehicle having a plurality of working modes allowing working in accordance with a load state includes an engine, an exhaust gas purification apparatus, a reducing agent tank, a state determination portion, and an engine control unit. The exhaust gas purification apparatus purifies a nitrogen oxide in an exhaust gas. The reducing agent tank stores a reducing agent. The state determination portion determines a state of the reducing agent. The engine control unit controls output of the engine with the use of a restricted-operation engine output torque curve in which horsepower output from the engine is lower than horsepower output from the engine at the time when each of the plurality of working modes is selected, when a state of the reducing agent is equal to or lower than a reference value.

Claims

1. A work vehicle, comprising:

a selector for selecting a working mode among a plurality of working modes allowing working in accordance with a load state;

an engine;

an exhaust gas purification apparatus for purifying a nitrogen oxide in an exhaust gas emitted from said engine;

a reducing agent tank for storing a reducing agent to be supplied to said exhaust gas purification apparatus;

a state determination portion for determining a state of said reducing agent stored in said reducing agent tank; and

an engine control unit configured to control output of said engine in accordance with a state of said reducing agent determined by said state determination portion,

said engine control unit configured to control output of said engine based on a restricted-operation engine output torque curve in which horsepower output from the engine is lower than horsepower output from the engine at time when each of said plurality of working modes is selected by the selector, when a state of said reducing agent is equal to or lower than a reference value.

2. The work vehicle according to claim 1, wherein

said state determination portion determines a concentration of said reducing agent as the state of said reducing agent.

3. The work vehicle according to claim 1, further comprising:

a work implement;

a hydraulic actuator for driving said work implement;

a hydraulic pump for supplying hydraulic oil to said hydraulic actuator as said engine is driven; and

a pump control unit for controlling absorption torque of said hydraulic pump,

said pump control unit setting maximum absorption torque based on said restricted-operation engine output torque curve and a restricted pump absorption torque characteristic line set when the state of said reducing agent is equal to or lower than the reference value.

4. The work vehicle according to claim 1, wherein

said restricted-operation engine output torque curve is lower in at least one of a maximum number of rotations of the engine and torque than a normal-operation engine output torque curve set at the time when each of said plurality of working modes is selected.

5. The work vehicle according to claim 1, wherein

said restricted-operation engine output torque curve is set to be lower in horsepower by 5% or more than horsepower in accordance with a normal-operation engine output torque curve set at the time when each of said plurality of working modes is selected.

6. The work vehicle according to claim 1, further comprising a notification portion for giving notification of a result of determination by said state determination portion.