Engine output control via auto selection of engine output curve

• US 7,664,586 B2
• Filed: 08/22/2007
• Issued: 02/16/2010
• Est. Priority Date: 10/31/2003
• Status: Expired due to Fees

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Ozawa, Godo, Nishida, Harushige
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): SAMPLE, JONATHAN L
• Application Number:
  US11/843,462
• Publication Number:
  US 20080006027A1
• Time in Patent Office: 909 Days
• Field of Search: 701/50, 701/1, 701/51, 701/54, 701/84
• US Class Current: 701/50
• CPC Class Codes: E02F 9/2235 including an electronic controller
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: F02D 11/105 characterised by the function converting demand to actuation, e.g. a map indicating relations between an accelerator pedal position and throttle valve opening or target engine torque
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• 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 41/2422 Selective use of one or more tables

Abstract

An engine output controller provided in a bulldozer includes an output curve storage device storing a plurality of output curves of an engine and an output curve changing device selecting and shifting to one of the plurality of output curves. The output curve changing device, when a pressure of a blade tilt cylinder is equal to or more than a predetermined value, calls and shifts to a higher output curve from the output curve storage device. When an oil pressure is supplied to the tilt cylinder to tilt a blade and an operation is performed without reducing a soil pressing speed in this condition, the output curve changing device shifts the current output curve to the higher output curve to drive the engine. However, in many other cases, the output curve is automatically switched to a lower output curve to reduce an output of the engine. Thus, the fuel consumption is improved.

Claims

1. An engine output controller for a motor grader, comprising:

an output curve storage device which stores a plurality of output curves of an engine, an operation mode correspondence table including a plurality of operation-modes of the motor grader, and an output curve correspondence table in which each of the operation modes is linked with one of the output curves wherein the output curves of the engine are defined as engine revolutions plotted against one of engine torque and power output;

an operation-mode determination device which automatically judges an operation mode of the motor grader based on a blade height of a blade of the motor grader and a shift position of a transmission that transmits a driving force of the engine; and

an output curve changing device, coupled to the output curve storage device and the operation-mode determination device, which selects a higher output curve from the output curve storage device when the motor grader is judged by the operation mode determination device to be in a grading mode, and which selects a lower output curve from the output curve storage device when the motor grader is judged by the operation-mode determination device to be in a running mode;

wherein the engine output controller controls an output of the engine of the motor grader in accordance with the selected output curve.

2. The engine output controller according to claim 1, wherein the output curve changing device selects the higher output curve from the output curve storage device when the shift position of the transmission that transmits the driving force of the engine is a position equal to or more than a forward fourth-speed range.

3. An engine output controller for a hydraulic excavator, comprising:

an output curve storage device which stores a plurality of output curves of an engine, an operation-mode correspondence table including a plurality of operation-modes of the hydraulic excavator, and an output curve correspondence table in which each of the operation modes is linked with one of the output curves wherein the output curves of the engine are defined as engine revolutions plotted against one of engine torque and power output;

an operation-mode determination device which automatically judges whether the hydraulic excavator is performing a steering operation in a running mode based on a load of a working unit of the hydraulic excavator and an operation amount of running of the hydraulic excavator; and

an output curve changing device, coupled to the output curve storage device and the operation-mode determination device, which selects a higher output curve from the output curve storage device when the hydraulic excavator is in the running mode but only when the hydraulic excavator is judged by the operation-mode determination device to be performing a steering operation in the running mode.