Handheld engine-driven working machine

Patent metadata

Field	Value
Publication number	US-10415496-B2
Application number	US-201615134013-A
Country	US
Kind code	B2
Filing date	Apr 20, 2016
Priority date	Apr 24, 2015
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

An engine-driven working machine includes a controller, which varies a control value of a solenoid valve so as to decrease or increase an opening degree of the solenoid valve when a rotating speed of an engine is within a predetermined high rotating speed range and the rotating speed of the engine is lower or higher than a predetermined rotating speed, respectively. When the control value of the solenoid valve is varied so as to decrease the opening degree of the solenoid valve and corresponds to a predetermined opening degree larger than a fully-closed state, the control value is set to a limitation value.

First claim

What is claimed:

1. An engine-driven working machine comprising:
an engine including an electronically controlled carburetor; and
a controller connected to the electronically controlled carburetor;
wherein the electronically controlled carburetor includes a solenoid valve for adjusting an amount of supplying fuel into the electronically controlled carburetor,
wherein the controller is programmed to vary a control value of the solenoid valve so as to increase an opening degree of the solenoid valve when a rotating speed of the engine is within a predetermined high rotating speed range and the rotating speed of the engine is higher than a target rotating speed;
wherein the controller is programmed to vary the control value of the solenoid valve to a control calculation value calculated so as to decrease the opening degree of the solenoid valve, when the rotating speed of the engine is within the predetermined high rotating speed range, the rotating speed of the engine is lower than the target rotating speed, and the control calculation value is nearer a fully-opened state than a single limitation value which corresponds to a predetermined opening degree larger than a fully-closed state, and

wherein the controller is programmed to set the control value of the solenoid valve to the limitation value when the rotating speed of the engine is within the predetermined high rotating speed range, the rotating speed of the engine is lower than the target rotating speed, and the control calculation value equals to or is nearer the fully-closed state than the limitation value.

2. The engine-driven working machine according to claim 1 , wherein the limitation value is determined by varying a control value determined in a completion operation by a predetermined value toward a direction of opening the solenoid valve.

3. The engine-driven working machine according to claim 1 , wherein the engine-driven working machine is a chain saw, an engine cutter or a hedge trimmer.

Assignees

• Yamabiko Corp
• Iida Denki Kogyo Kk

Inventors

• Yamaguchi Shiro
• Otsuji Takamasa
• Matsumoto Kosuke
• Miyaki Hiroyuki
• Yamazaki Akira

Classifications

• F02M7/22

  fuel flow cross-sectional area being controlled dependent on air-throttle-valve position (the throttle valve being slidably arranged transversely to air passage F02M9/06) · CPC title

• F02M7/133 Primary

  Auxiliary jets, i.e. operating only under certain conditions, e.g. full power (means for enriching charge at high combustion-air flow F02M7/04; means for enriching charge on sudden throttle opening, i.e. at acceleration F02M7/06) · CPC title

• F02D2400/06

  Small engines with electronic control, e.g. for hand held tools · CPC title

• F02D35/0069

  Controlling the fuel flow only (F02D35/0076, F02D35/0084 take precedence) · CPC title

• F02D35/0053

  by means of a carburettor · CPC title