Patent US5286171A successfully refreshed from Google Patents.
US5286171A
Expired / Lapsed
US
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Method for controlling engine for driving hydraulic pump to operate hydraulic actuator for construction equipment
Assignee: Caterpillar SARL
•
Filing: 1992-03-10
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Granted: 1994-02-15
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Expires: 2012-03-10
Abstract
Abstract In a method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in a construction machinery, a fuel flow supplied to the engine is decreased so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and the fuel flow is increased to increase the output rotational speed of the engine when a load of the engine for driving the hydraulic pump is more than a first level after the engine output decreasing step.
Inventors
- 👤 Isao Murota
- 👤 Naoyuki Moriya
- 👤 Kazuhito Nakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:56
CPC Classifications
F; F02; F02D; F02D29/00; F02D29/04; E; E02; E02F; E02F9/00; E02F9/20; E02F9/22; E02F9/2246
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
152 words
A method for controlling an engine for driving a hydraulic pump to supply to pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump is measured from a difference between an actual output rotational speed of the engine and an output rotational speed of the engine which is obtainable when an action of the hydraulic actuator is stopped.
Claim 2
Independent Claim
152 words
A method for controlling an engine for driving a hydraulic pump to supply to pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump is measured from a difference between an actual output rotational speed of the engine and an output rotational speed of the engine which is obtainable when an action of the hydraulic actuator is stopped.
Claim 3
Dependent Claim
30 words
A method according to claim 1, wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level.
Claim 4
Independent Claim
150 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to step the action of the hydraulic actuator.
Claim 5
Independent Claim
150 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to step the action of the hydraulic actuator.
Claim 6
Dependent Claim
53 words
A method according to claim 3, wherein the fuel flow is decreased in the engine output decreasing step, when the hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control the action of the hydraulic actuator is operated to step the action of the hydraulic actuator during a predetermined time.
Claim 7
Dependent Claim
71 words
A method according to claim 3, wherein the fuel flow is decreased in the engine output decreasing step, when the hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control the action of the hydraulic actuator is operated to step the action of the hydraulic actuator and a range in which the load of the engine varies is kept narrower than a predetermined degree during a predetermined time.
Claim 8
Dependent Claim
83 words
A method according to claim 3, wherein the fuel flow is decreased in the engine output decreasing step, when the hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control the action of the hydraulic actuator is operated to stop the action of the hydraulic actuator and the load of the engine is less than the second level and a range in which the load of the engine varies is kept narrower than a predetermined degree during a predetermined time.
Claim 9
Independent Claim
128 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump calculated based on an actual output torque of the engine.
Claim 10
Independent Claim
128 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump calculated based on an actual output torque of the engine.
Claim 11
Independent Claim
133 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump calculated based on an actual flow rate of the pressurized fluid supplied to the actuator.
Claim 12
Independent Claim
133 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump calculated based on an actual flow rate of the pressurized fluid supplied to the actuator.
Claim 13
Independent Claim
125 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is not decreased when prevention of the decrease of the fuel flow is ordered.
Claim 14
Independent Claim
125 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is not decreased when prevention of the decrease of the fuel flow is ordered.
Claim 15
Independent Claim
175 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein fuel flow is increased to increase the output rotational speed of the engine, when the load of the engine for driving the hydraulic pump is more than the first level and a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to generate the action of the hydraulic actuator after the engine output decreasing step.
Claim 16
Independent Claim
175 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein fuel flow is increased to increase the output rotational speed of the engine, when the load of the engine for driving the hydraulic pump is more than the first level and a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to generate the action of the hydraulic actuator after the engine output decreasing step.
Claim 17
Independent Claim
128 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump is calculated from an engine speed and governor lever position.
Claim 18
Independent Claim
128 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump is calculated from an engine speed and governor lever position.
Claim 19
Independent Claim
130 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump is calculated from an engine speed and a neutral detection pressure switch.
Claim 20
Independent Claim
130 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the load of the engine for driving the hydraulic pump is calculated from an engine speed and a neutral detection pressure switch.
Claim 21
Independent Claim
136 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is kept less than a second level during a predetermined time.
Claim 22
Independent Claim
136 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is kept less than a second level during a predetermined time.
Claim 23
Independent Claim
162 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level and a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to stop the action of the hydraulic actuator.
Claim 24
Independent Claim
162 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level and a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to stop the action of the hydraulic actuator.
Claim 25
Independent Claim
166 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level and a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to stop the action of the hydraulic actuator during a predetermined time.
Claim 26
Independent Claim
166 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level and a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to stop the action of the hydraulic actuator during a predetermined time.
Claim 27
Independent Claim
161 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased gradually in the engine output decreasing step, when the load of the engine is less than a second level and the decrease of the fuel flow is stopped when the load of the engine is not less than the second level and is less than the first level.
Claim 28
Independent Claim
161 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased gradually in the engine output decreasing step, when the load of the engine is less than a second level and the decrease of the fuel flow is stopped when the load of the engine is not less than the second level and is less than the first level.
Claim 29
Independent Claim
141 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is kept less than a second level, the second level being less than the first level.
Claim 30
Independent Claim
141 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is kept less than a second level, the second level being less than the first level.
Claim 31
Independent Claim
170 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level, and wherein the fuel flow is decreased, also when a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to stop the action of the hydraulic actuator.
Claim 32
Independent Claim
170 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level, and wherein the fuel flow is decreased, also when a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to stop the action of the hydraulic actuator.
Claim 33
Independent Claim
174 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level, and wherein the fuel flow is decreased, also when a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to stop the action of the hydraulic actuator during a predetermined time.
Claim 34
Independent Claim
174 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level, and wherein the fuel flow is decreased, also when a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to stop the action of the hydraulic actuator during a predetermined time.
Claim 35
Independent Claim
170 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level, and wherein the fuel flow is increased, also when a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to generate the action of the hydraulic actuator.
Claim 36
Independent Claim
170 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level, and wherein the fuel flow is increased, also when a hydraulic valve arranged between the hydraulic pump and the hydraulic actuator to control an action of the hydraulic actuator is operated to generate the action of the hydraulic actuator.
Claim 37
Independent Claim
172 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level, and wherein the fuel flow is decreased when the load of the engine is less than the second level and a range in which the load of the engine varies is kept narrower than a predetermined degree during a predetermined time.
Claim 38
Independent Claim
172 words
A method for controlling an engine for driving a hydraulic pump to supply a pressurized fluid to at least one hydraulic actuator in construction equipment, comprising the steps of: engine output decreasing step for decreasing a fuel flow supplied to the engine so that an output rotational speed of the engine is decreased to decrease an excess output of the engine, and engine output increasing step for increasing the fuel flow to increase the output rotational speed of the engine when an actual condition of the load of the engine driving the hydraulic pump is more than a first level after the engine output decreasing step, and wherein the fuel flow is decreased in the engine output decreasing step, when the load of the engine is less than a second level, and wherein the fuel flow is decreased when the load of the engine is less than the second level and a range in which the load of the engine varies is kept narrower than a predetermined degree during a predetermined time.
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