HANDHELD ENGINE WORK MACHINE

PROBLEM TO BE SOLVED: To provide a handheld engine work machine which solves reduction in output and reduction in acceleration within a medium speed range during work.SOLUTION: An internal combustion engine (2) comprises an ignition control device (12). The ignition control device (12) is capable of switching between a normal mode and a work mode. In the normal mode, ignition timing is advanced from a first BTDC angle (A1) to a second BTDC angle (A2) with increase in rotation speed in a medium speed range (32), and the ignition timing is maintained at the second BTDC angle (A2) in a high speed range (34). In the work mode, the ignition timing is maintained at the second BTDC angle (A2) in the high speed range (34), and the ignition timing is advanced further than a third BTDC angle (A3) between the first BTDC angle (A1) and the second BTDC angle (A2) in the medium speed range (32).SELECTED DRAWING: Figure 5 【課題】作業中の中速度範囲における出力の低下及び加速の低下を改善した手持ち式エンジン作業機を提供する。【解決手段】本発明による内燃エンジン(2)は、点火制御装置(12)を有する。点火制御装置(12)は、中速度範囲(32)において回転速度の上昇とともに点火タイミングを第１のＢＴＤＣ角度(A1)から第２のＢＴＤＣ角度(A2)に進角させ且つ高速度範囲(34)において点火タイミングを第２のＢＴＤＣ角度(A2)に維持する通常モードと、高速度範囲(34)において点火タイミングを第２のＢＴＤＣ角度(A2)に維持し且つ中速度範囲(32)において点火タイミングを第１のＢＴＤＣ角度(A1)と第２のＢＴＤＣ角度(A2)の間の第３のＢＴＤＣ角度(A3)よりも進角させる作業モードとの間を切換え可能である。【選択図】図５