Engine speed control device for industrial vehicle

• US 9,091,221 B2
• Filed: 06/16/2010
• Issued: 07/28/2015
• Est. Priority Date: 06/17/2009
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Hyodo, Koji, Yoshikawa, Masaki, Aoki, Tadayoshi, Hara, Katsutaka
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Stroud, James E
• Application Number:
  US13/378,969
• Publication Number:
  US 20120094803A1
• Time in Patent Office: 1,868 Days
• Field of Search: 701/99, 701/50, 475/118, 477/183
• US Class Current: 1/1
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 2510/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 2554/00 Input parameters relating to objects
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60Y 2200/415 Wheel loaders
• CPC Class Codes: E02F 9/2025 Particular purposes of control systems not otherwise provided for E02F3/16, E02F3/26, sub-groups of E02F3/43, E02F3/651, sub-groups of E02F3/84, E02F3/907, E02F5/145 take precedence
• CPC Class Codes: E02F 9/2079 Control of mechanical transmission for hydrostatic transmission or hydraulic torque converter E02F9/2253
• CPC Class Codes: E02F 9/2083 Control of vehicle braking systems
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: F02D 2200/501 Vehicle speed
• 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 41/022 in relation with the clutch status

Abstract

An engine speed control device for an industrial vehicle includes an approach detector that detects an approach of the industrial vehicle to an object to be approached; and an engine speed controller that restricts an upper limit of a rotation speed of an engine when the approach detector detects an approach of the industrial vehicle to an object to be approached.

Claims

1. An engine speed control device for an industrial vehicle, comprising:

a braking force information obtaining unit that obtains information related to a magnitude of braking force of the industrial vehicle;

a clutch cut off control device that controls engagement and release of a forward clutch and a reverse clutch so as to release the forward clutch and the reverse clutch when it is decided that the braking force is equal to or greater than a first predetermined braking force based on the information obtained by the braking force information obtaining unit;

a selector that selects whether or not to allow the clutch cut off control device to release the forward clutch and the reverse clutch;

an accelerator pedal that is operated to change a rotation speed of an engine between a minimum rotation speed and a maximum rotation speed depending on an operation amount of the accelerator pedal;

an approach detector that detects that the industrial vehicle has approached an object when the forward clutch provided in a transmission of the engine of the industrial vehicle is in a connected state and it is decided that the braking force of the industrial vehicle is equal to or greater than a second predetermined braking force; and

an engine speed controller that;

(a) restricts an upper limit of the rotation speed of the engine instructed by the accelerator pedal by gradually reducing the upper limit of the rotation speed of the engine to a rotation speed that is smaller than the maximum rotation speed when the selector selects not releasing the forward clutch and the reverse clutch and the approach detector detects that the industrial vehicle has approached the object, and (b) controls the engine to rotate at the rotation speed instructed by the accelerator pedal without reducing the upper limit of the rotation speed of the engine when the selector selects not releasing the forward clutch and the reverse clutch and the approach detector determines that the forward clutch provided in the transmission of the engine of the industrial vehicle is in the connected state and the braking force of the industrial vehicle is smaller than the second predetermined braking force.

2. The engine speed control device for an industrial vehicle according to claim 1, wherein:

the approach detector determines that the industrial vehicle has approached the object if the forward clutch provided in the transmission of the engine of the industrial vehicle is in the connected state and it is decided that a travel speed of the industrial vehicle is equal to or less than a predetermined speed and that the braking force of the industrial vehicle is equal to or greater than the second predetermined braking force.

3. The engine speed control device for the industrial vehicle according to claim 1, wherein:

the approach detector determines that the industrial vehicle has approached the object if the forward clutch provided in the transmission of the engine of the industrial vehicle is in the connected state and it is decided that a height of a working machine device provided in the industrial vehicle is equal to or greater than a predetermined height and that the braking force of the industrial vehicle is equal to or greater than the second predetermined braking force.

4. The engine speed control device for the industrial vehicle according to claim 1, wherein:

the engine speed controller restricts the upper limit of the rotation speed of the engine such that the upper limit of the rotation speed of the engine becomes lower with an increase in the braking force.