201043773 六、發明說明 【發明所屬之技術領域】 本發明關於引擎所搭載的引擎轉速偵測裝置。 【先前技術】 以往，爲了計算出引擎轉速或活塞的上死點位置，藉 由感應器等的偵測手段來偵測出在曲軸固定設置的位置偵 0 測構件，而計算出引擎的轉速及活塞的位置。可是，在這 種構造的偵測裝置，是曲軸一次旋轉進行一次偵測，所以 在曲軸的轉速在一次旋轉中變化的情況，則會有無法正確 計算出引擎轉速或活塞的上死點位置的缺點。 因此，習知的引擎轉速偵測裝置的技術，除了位置偵 測構件的偵測之外，還藉由感應器等的偵測手段偵測出在 曲軸固定設置的環齒輪的齒頂，則即使曲軸的轉速變化， 也能正確地計算出引擎轉速及活塞位置。 Q 可是，在上述專利文獻所揭示的構造，爲了要正確計 算出引擎轉速與活塞位置，環齒輪偵測用的偵測手段需要 增加新的感應器，而成爲成本上升的原因。而在環齒輪的 輪齒有缺損的情況，則無法偵測出曲軸的正確位置，會有 在引擎轉速與活塞位置產生誤差的問題。 [專利文獻1 ] 日本特許第3326866號公報 【發明內容】 -5- 201043773 [發明欲解決的課題] 本發明’是鑑於如上述的課題，其目的要提供一種引 擎轉速偵測裝置，不用增加新的偵測手段，可穩定地計算 出正確的引擎轉速及活塞的上死點位置。 [用以解決課題的手段] 在第1發明，是具備有：與引擎的曲軸連動而旋轉， 在以板面的旋轉軸作爲中心的同一圓上在預定的等角度間 隔形成有複數的偵測用部位的飛輪；用來偵測上述各偵測 用部位的偵測手段；以及根據來自上述偵測手段的偵測訊 號’將偵測出上述各偵測用部位的其中一個偵測用部位的 上述曲軸的一定旋轉角度作爲基準位置，當上述曲軸旋轉 上述一定旋轉角度時，計算出引擎轉速及活塞的上死點位 置的計算手段。 在第2發明，上述各偵測用部位，在將上述飛輪的旋 轉軸作爲中心的同一圓上，作爲與上述旋轉軸平行形成的 非貫穿孔，其中一個作爲盲孔。 在第3發明，上述偵測手段，藉由其中一側與上述偵 測用部位也就是非貫穿孔嵌合’另一側與上述偵測手段嵌 合的定位夾具’而可進行定位。 [發明效果] 作爲本發明的效果’可達到以下所示的效果。 如第1發明的構造，則不會產生因爲環齒輪等的缺損 -6- 201043773 導致的偵測誤差或錯誤偵測。藉此，不用增加新的偵測手 段，而能穩定地計算出正確的引擎轉速及活塞的上死點位 置。 如第2發明的構造，能容易地偵測出基準位置。藉 此，不用增加新的偵測手段，而能穩定地計算出正確的引 擎轉速及活塞的上死點位置。 如第3發明的構造，能根據偵測用孔的位置而正確地 Q 配設偵測手段。藉此，不用增加新的偵測手段，而能穩定 地計算出正確的引擎轉速及活塞的上死點位置。 【實施方式】 接著用第1圖及第2圖，針對本發明的引擎轉速偵測 裝置的實施方式也就是引擎轉速偵測裝置1來說明。第1 圖（a)的箭頭U方向作爲上方向來限定上下方向，第1圖 (b)的箭頭F方向作爲前方向來限定前後方向。 Q 引擎轉速偵測裝置1，如第1圖所示，具備於引擎 1 0，該引擎1 0具備有沒有圖示的6個氣缸，偵測出：藉 由沒有圖示的各活塞的往復運動而轉動的曲軸1 1的轉 速，計算出：引擎的轉速R及各活塞的上死點位置也就是 TDC1、TDC2、TDC3。引擎轉速偵測裝置1，主要是由： 飛輪2、偵測手段3、計算手段4所構成。本實施方式的 引擎10的氣缸的數量爲6個，沒有圖示的第一活塞及第 六活塞、沒有圖示的第二活塞及第四活塞 '沒有圖示的第 三活塞及第五活塞分別構成相同相位。第一活塞及第六活 201043773 塞的上死點位置爲TDC 1，第二活塞及第四活塞的上死點 位置爲TDC2，第三活塞及第五活塞的上死點位置爲 TDC3。本實施方式的引擎10，是柴油引擎或汽油引擎都 可以，汽缸數量及各活塞的相位，並不限定於本實施方 式。 飛輪2，固定設置於曲軸1 1，使曲軸1 1穩定旋轉’ 並且藉由與曲軸11連動旋轉而能偵測出曲軸角度Θ。飛 輪2，作爲偵測用部位的一個例子的複數的偵測用孔2a、 2a…，在以飛輪2的板面的旋轉軸爲中心的同一圓上形成 爲與上述旋轉軸平行。複數的偵測用孔2 a、2 a…，如第1 圖（b)所示是非貫穿孔，在上述圓上以預定的等角度間隔 形成。偵測用孔2a、2a…的其中一個，是作成爲盲孔 (blank hole)2b。飛輪2，是固定設置於曲軸11，當第一 活塞及第六活塞到達上死點位置TDC 1時，肓孔2b位於 曲軸1 1的正上方。 偵測手段3，是以磁性接近感應器等所構成，是用來 偵測出偵測用孔2a、2a···。偵測手段3，配置在：與偵測 用孔2a、2a···相對向的接近位置，在引擎1 〇主體等處， 隔介著固定件1 2而固定設置。偵測手段3，當偵測到偵 測用孔2 a時’則將預定的訊號傳輸到計算手段4。偵測 手段3只要是用來偵測出偵測用孔2 a即可，並不限定於 本實施方式。 計算手段4，是用來計算出引擎轉速R及各活塞的上 死點位置TDC1、TDC2、TDC3。計算手段4，具體來說可 201043773 以是以匯流排連接：CPU' ROM、RAM、HDD等的構造， 或者由單一晶片的L S I等所構成。在計算手段4容納有各 種程式及資料’用來計算出引擎轉速R及各活塞的上死點 位置 TDC1、TDC2、TDC3。 計算手段4，設定有：從偵測手段3偵測出肓孔2 b 起’到第一活塞及第六活塞到達上死點位置TDC1爲止的 曲軸的旋轉角度1、第二活塞及第四活塞到達上死點位 Q 置TDC2爲止的曲軸的旋轉角度Θ2、第三活塞及第五活 塞到達上死點位置T D C 3爲止的曲軸的旋轉角度0 3。 計算手段4，如第2圖所示，連接於偵測手段3，當 偵測手段3偵測到偵測用孔2a時取得所輸出的預定訊 號，則可計算出引擎轉速R及各活塞的上死點位置 TDC1、TDC2、TDC3。 計算手段4，連接於：用來控制引擎1 〇的電子控制 單元（以下僅記載爲「ECU」）5，或與ECU5構成爲一體， 〇 而可將計算出的引擎轉速R及各活塞的上死點位置 TDC1、TDC2、TDC3傳輸到ECU5。這裡的ECU5，是連 接於引擎10、顯示手段6及輸入手段7等，將計算手段4 計算出的引擎轉速R顯示於顯示手段6，根據計算手段4 計算出的各氣缸的上死點位置TDC1、TDC2、TDC3，進 行：因應來自輸入手段7的輸入値的引擎1 〇的控制。 接著，用第3圖來針對本發明的第一實施方式的引擎 轉速偵測裝置1的計算手段4的計算型態加以說明。 計算手段4，當偵測手段3偵測出偵測用孔2a時， -9 - 201043773 從偵測手段3取得偵測訊號。 目十算手段4 ’根據偵測訊號的偵測間隔來計算出引擎 轉速R ’而將其傳輸到ECU5。 曰十算手段4 ’比較偵測訊號的偵測間隔、與該偵測間 隔之前的偵測間隔，在該偵測間隔爲預定値以上的情況， 則判斷爲偵測到盲孔2 b，傳輸到E C U 5。可是，取代設置 盲孔2b ’將肓孔2b的部分的偵測用孔2a的深度作得較 淺或較深或作成貫穿孔，藉此讓偵測手段3得到的偵測値 與其他偵測用孔2b的偵測値不一樣，則能當作基準位 置。在該情況’盲孔2b的情況，在產生碰撞或有負荷施 加的情況等’脈衝的間隔延長而可能判斷爲盲孔2b，藉 由讓偵測値不同則能確實偵測出基準位置。 計算手段4 ’以偵測到盲孔2b的曲軸角度θ作爲基 準位置’而以旋轉角度0 1旋轉曲軸1 1時，則判斷第一 活塞及第六活塞到達上死點位置TDC丨而將訊號傳輸到 ECU5。 計算手段4 ’以偵測到盲孔2b的曲軸角度0作爲基 準位置’而以旋轉角度θ 2旋轉曲軸1 1時，則判斷第二 活塞及第四活塞到達上死點位置TDC2而將訊號傳輸到 ECU5。 計算手段4 ’以偵測到盲孔2b的曲軸角度0作爲基 準位置’而以旋轉角度Θ 3旋轉曲軸1 1時，則判斷第三 活塞及第五活塞到達上死點位置TDC3而將訊號傳輸到 ECU5。 -10- 201043773 藉由該構造，計算手段4，偵測出肓孔2 b之後，當 曲軸11旋轉預先設定的旋轉角度時，傳輸訊號，所以能 考慮上述訊號到達至ECU5的時間而傳輸該訊號。於是， 計算手段4 ’例如與偵測到盲孔2b時同時傳輸訊號的方 式相比’能夠更確實地進行：第一活塞及第六活塞已到達 上死點位置TD C 1的判斷、第二活塞及第四活塞已到達上 死點位置TDC2的判斷、第三活塞及第五活塞已到達上死 Q 點位置TDC3的判斷。 ECU5 ’在從計算手段4取得引擎轉速R之後，在顯 示手段6顯示引擎轉速R。ECU5，從計算手段4取得引 擎轉速R及上死點位置TDC1、TDC2、TDC3的訊號之 後，根據上述訊號而依照輸入手段7的輸入値來控制引擎 10° 接著，使用第4圖，針對本發明的第一實施方式的引 擎轉速偵測裝置1的偵測手段3的定位型態來說明。 Q 偵測手段3，將偵測用孔2a作爲基準而固定於固定 件1 2。偵測手段3，藉由定位夾具3 a而定位。 定位夾具3a，其中一側形成爲可與偵測用孔2a無間 隙地嵌合的凸部，另一側形成爲可與偵測手段3無間隙地 嵌合的凹部。 定位夾具3a，當第一活塞及第六活塞在上死點位置 TDC1時，從位於曲軸1 1的正上方的盲孔2b朝與飛輪2 的旋轉方向相反的方向，使其中一側的凸部嵌合於在旋轉 角度θ 1的位置的偵測用孔2a，藉由將偵測手段3嵌合於 -11 - 201043773 另一側的凹部，來決定偵測手段3的位置。偵測 在被定位夾具3 a定位的狀態，藉由螺母3b固定 12 ° 如上述，是具備有：與引擎10的曲軸11 轉，在以旋轉軸作爲中心的圓周上與旋轉軸平行 複數的偵測用孔2a的飛輪2 ;用來偵測偵測用？[ 測手段3 ;以及根據來自偵測手段3的偵測訊號 引擎轉速R及活塞的上死點位置TDC1、TDC2、 計算手段4。 藉由該構造，則不會產生因爲環齒輪等的缺 偵測誤差或錯誤偵測。藉此，不用增加新的偵測 能穩定地計算出正確的引擎轉速R及活塞的上 TDC1、TDC2、TDC3。 複數的偵測用孔2 a，是形成在等角度間隔 孔，並且其中一個作爲盲孔2b。 藉由作成這種構造，例如與偵測用孔2 a作 的構造相比，可以維持飛輪2的剛性，並且. 2a ’藉由調整孔的深度則能對應各種偵測手段。 偵測用孔2a的其中一個作爲盲孔2b，則能容易 準位置。藉此’不用增加新的偵測手段，而能穩 出正確的引擎轉速R及活塞的上死點位置TDC1 TDC3。 偵測手段3 ’藉由其中一側與偵測用孔2 a 一側與偵測手段3嵌合的定位夾具3 a，則可進行 手段3， 於固定件 連動而旋 地形成有 」2a的偵 ，計算出 TDC3 的 損導致的 手段，而 死點位置 的非貫穿 爲貫穿孔 偵測用孔 而藉由將 偵測出基 定地計算 ' TDC2、 嵌合，另 定位。 -12- 201043773 藉由作成這種構造，則能根據偵測用孔2a的位置正 確地配設偵測手段3。藉此，不用增加新的偵測手段，而 能穩定地計算出正確的引擎轉速R及活塞的上死點位置 TDC1、TDC2、TDC3。 [產業上的可利用性] 本發明，可利用於：用來計算出引擎轉速及活塞的上 ❹ 死點位置的引擎轉速偵測裝置的技術，可適用於各種引 擎。 【圖式簡單說明】 第1圖（a)是本發明的實施方式的引擎轉速偵測裝置 的顯示圖，（b)是第1圖（a)的A— A剖面圖。 第2圖是本發明的實施方式的引擎轉速偵測裝置的構 造圖。 Q 第3圖是本發明的實施方式的引擎轉速偵測裝置的時 序圖。 第4圖是本發明的實施方式的引擎轉速偵測裝置的偵 測手段定位構造圖。 【主要元件符號說明】 1 :引擎轉速偵測裝置 2 :飛輪 2a :偵測用孔 -13- 201043773 3 :偵測手段 4 :計算手段 1 1 :曲軸 T D C 1 :上死點位置 TDC2 ：上死點位置 T D C 3 :上死點位置 R :引擎轉速 0201043773 VI. Description of the Invention [Technical Field] The present invention relates to an engine rotation speed detecting device mounted on an engine. [Prior Art] In the past, in order to calculate the engine speed or the top dead center position of the piston, the detection means such as the sensor detects the position detecting member at the fixed position of the crankshaft, and calculates the engine speed and The position of the piston. However, in the detecting device of this configuration, the crankshaft is rotated once for detection, so that when the rotational speed of the crankshaft changes in one rotation, the engine rotational speed or the top dead center position of the piston cannot be correctly calculated. Disadvantages. Therefore, the technique of the conventional engine speed detecting device detects the tooth tip of the ring gear fixedly disposed on the crankshaft by means of a detecting means such as a sensor, in addition to the detection of the position detecting member, even if The engine speed and piston position can also be correctly calculated from the change in the rotational speed of the crankshaft. Q However, in the structure disclosed in the above patent documents, in order to accurately calculate the engine speed and the piston position, the detection means for detecting the ring gear needs to add a new inductor, which is a cause of an increase in cost. On the other hand, if the teeth of the ring gear are defective, the correct position of the crankshaft cannot be detected, and there is a problem that the engine speed and the piston position are in error. [Patent Document 1] Japanese Patent No. 3326866 [Description of the Invention] -5-201043773 [Problem to be Solved by the Invention] The present invention has been made in view of the above problems, and an object thereof is to provide an engine rotation speed detecting device without adding a new one. The detection method can stably calculate the correct engine speed and the top dead center position of the piston. [Means for Solving the Problem] In the first aspect of the invention, the rotation is performed in conjunction with the crankshaft of the engine, and a plurality of detections are formed at predetermined equiangular intervals on the same circle centered on the rotation axis of the plate surface. a flywheel for the use portion; a detecting means for detecting each of the detecting portions; and detecting a detecting portion of each of the detecting portions based on the detecting signal from the detecting means The predetermined rotation angle of the crankshaft is used as a reference position, and when the crankshaft is rotated by the predetermined rotation angle, a calculation means for calculating the engine rotation speed and the top dead center position of the piston is calculated. In the second aspect of the invention, each of the detecting portions is a non-through hole formed in parallel with the rotating shaft on the same circle having the rotating shaft of the flywheel as a center, and one of the detecting portions is a blind hole. According to a third aspect of the invention, the detecting means can be positioned by a positioning jig which is fitted to the detecting portion, that is, the non-through hole, and the other side is engaged with the detecting means. [Effects of the Invention] The effects described below can be achieved. According to the configuration of the first aspect of the invention, detection errors or false detections due to the defect of the ring gear or the like -6-201043773 are not generated. In this way, the correct engine speed and the top dead center position of the piston can be stably calculated without adding a new detection means. According to the configuration of the second aspect of the invention, the reference position can be easily detected. Therefore, it is possible to stably calculate the correct engine speed and the top dead center position of the piston without adding new detection means. According to the structure of the third aspect of the invention, the detecting means can be correctly Q-positioned in accordance with the position of the detecting hole. In this way, the correct engine speed and the top dead center position of the piston can be stably calculated without adding new detection means. [Embodiment] Next, an embodiment of an engine rotation speed detecting device according to the present invention, that is, an engine rotation speed detecting device 1 will be described with reference to Figs. 1 and 2 . The arrow U direction of Fig. 1(a) defines the vertical direction as the upper direction, and the arrow F direction of Fig. 1(b) defines the front-rear direction as the front direction. As shown in Fig. 1, the engine speed detecting device 1 is provided in the engine 10, and the engine 10 is provided with six cylinders (not shown), and detects reciprocation of each piston (not shown). The rotational speed of the crankshaft 11 is calculated as follows: the rotational speed R of the engine and the top dead center positions of the pistons are TDC1, TDC2, and TDC3. The engine speed detecting device 1 is mainly composed of: a flywheel 2, a detecting means 3, and a calculating means 4. The number of cylinders of the engine 10 of the present embodiment is six, and the first piston and the sixth piston (not shown), the second piston and the fourth piston (not shown), respectively, the third piston and the fifth piston (not shown) Form the same phase. The first piston and the sixth piston 201043773 The top dead center position of the plug is TDC 1, the top dead center position of the second piston and the fourth piston is TDC2, and the top dead center position of the third piston and the fifth piston is TDC3. The engine 10 of the present embodiment may be a diesel engine or a gasoline engine, and the number of cylinders and the phase of each piston are not limited to the present embodiment. The flywheel 2 is fixedly disposed on the crankshaft 1 to stably rotate the crankshaft 11 and can detect the crank angle Θ by rotating in conjunction with the crankshaft 11. The flywheel 2 has a plurality of detecting holes 2a, 2a, ... as an example of the detecting portion, and is formed in parallel with the rotating shaft on the same circle centering on the rotating shaft of the plate surface of the flywheel 2. The plurality of detecting holes 2a, 2a, ... are non-through holes as shown in Fig. 1(b), and are formed at predetermined equiangular intervals on the circle. One of the detecting holes 2a, 2a, ... is formed as a blank hole 2b. The flywheel 2 is fixedly disposed on the crankshaft 11. When the first piston and the sixth piston reach the top dead center position TDC 1, the bore 2b is located directly above the crankshaft 11. The detecting means 3 is constituted by a magnetic proximity sensor or the like for detecting the detecting holes 2a, 2a, .... The detecting means 3 is disposed at a position close to the detecting hole 2a, 2a, ..., and is fixedly disposed via the fixing member 12 at the main body of the engine 1 or the like. The detecting means 3, when the detecting hole 2a is detected, transmits the predetermined signal to the calculating means 4. The detecting means 3 is not limited to the embodiment as long as it is for detecting the detecting hole 2a. The calculation means 4 is for calculating the engine speed R and the top dead center positions TDC1, TDC2, and TDC3 of the respective pistons. The calculation means 4, specifically, 201043773, is constructed by a bus bar connection: a CPU 'ROM, a RAM, an HDD, or the like, or a single chip L S I or the like. The calculation means 4 accommodates various programs and data 'for calculating the engine speed R and the top dead center positions TDC1, TDC2, and TDC3 of the respective pistons. The calculating means 4 is configured to: detect the rotation angle of the crankshaft from the detecting means 3 to the first piston and the sixth piston reaching the top dead center position TDC1, the second piston and the fourth piston The rotation angle θ of the crankshaft until the top dead center Q is set to TDC2, and the rotation angle of the crankshaft until the third piston and the fifth piston reach the top dead center position TDC3 are 0 3 . The calculation means 4, as shown in FIG. 2, is connected to the detecting means 3. When the detecting means 3 detects the detected hole 2a and obtains the output predetermined signal, the engine speed R and the pistons can be calculated. Top dead center positions TDC1, TDC2, TDC3. The calculation means 4 is connected to an electronic control unit (hereinafter simply referred to as "ECU") 5 for controlling the engine 1 or integrated with the ECU 5, and the calculated engine rotational speed R and the upper piston can be calculated. The dead center positions TDC1, TDC2, and TDC3 are transmitted to the ECU 5. Here, the ECU 5 is connected to the engine 10, the display means 6, the input means 7, and the like, and the engine rotation speed R calculated by the calculation means 4 is displayed on the display means 6, and the top dead center position TDC1 of each cylinder calculated based on the calculation means 4. , TDC2, TDC3, perform: Control of the engine 1 因 in response to the input 値 from the input means 7. Next, the calculation type of the calculation means 4 of the engine rotation speed detecting device 1 according to the first embodiment of the present invention will be described with reference to Fig. 3. In the calculation means 4, when the detecting means 3 detects the detecting hole 2a, -9 - 201043773 obtains the detecting signal from the detecting means 3. The imaginary means 4' calculates the engine speed R' based on the detection interval of the detection signal and transmits it to the ECU 5.曰10 calculation means 4 'Comparing the detection interval of the detection signal with the detection interval before the detection interval, if the detection interval is more than the predetermined threshold, it is determined that the blind hole 2 b is detected, and the transmission is detected. Go to ECU 5. However, instead of providing the blind hole 2b', the depth of the detecting hole 2a of the portion of the pupil 2b is made shallower or deeper or made as a through hole, thereby allowing the detection means 3 to detect and other detections. The detection of the hole 2b is different, and it can be regarded as the reference position. In this case, in the case of the blind hole 2b, the interval of the pulse is extended in the case where a collision or a load is applied, and the blind hole 2b may be determined, and the reference position can be surely detected by making the detection flaw different. When the calculation means 4' detects the crank angle θ of the blind hole 2b as the reference position ' while rotating the crankshaft 1 1 at the rotation angle 0 1 , it is determined that the first piston and the sixth piston reach the top dead center position TDC 丨 and the signal is received Transfer to ECU5. When the calculating means 4' detects the crank angle 0 of the blind hole 2b as the reference position ' while rotating the crankshaft 1 1 at the rotation angle θ 2 , it is determined that the second piston and the fourth piston reach the top dead center position TDC2 to transmit the signal Go to ECU5. When the calculating means 4' detects the crank angle 0 of the blind hole 2b as the reference position ' while rotating the crankshaft 1 1 at the rotation angle Θ 3, it is judged that the third piston and the fifth piston reach the top dead center position TDC3 to transmit the signal. Go to ECU5. -10-201043773 With this configuration, the calculation means 4, after detecting the pupil 2b, transmits the signal when the crankshaft 11 rotates by a predetermined rotation angle, so that the signal can be transmitted in consideration of the time when the signal reaches the ECU 5 . Therefore, the calculation means 4' can be performed more reliably than the manner in which the signal is transmitted simultaneously when the blind hole 2b is detected, the determination that the first piston and the sixth piston have reached the top dead center position TD C 1 , and the second The piston and the fourth piston have reached the judgment of the top dead center position TDC2, and the third piston and the fifth piston have reached the position of the upper dead Q point position TDC3. The ECU 5' displays the engine rotation speed R on the display means 6 after acquiring the engine rotation speed R from the calculation means 4. The ECU 5 obtains the signals of the engine rotation speed R and the top dead center positions TDC1, TDC2, and TDC3 from the calculation means 4, and then controls the engine 10 according to the input signal of the input means 7 based on the signal. Next, using the fourth figure, the present invention is used. The positioning type of the detecting means 3 of the engine rotational speed detecting device 1 of the first embodiment is explained. The Q detecting means 3 is fixed to the fixing member 12 by using the detecting hole 2a as a reference. The detecting means 3 is positioned by the positioning jig 3a. The positioning jig 3a is formed with a convex portion that can be fitted into the detecting hole 2a without a gap, and the other side is formed as a concave portion that can be fitted to the detecting means 3 without a gap. The positioning jig 3a, when the first piston and the sixth piston are at the top dead center position TDC1, from the blind hole 2b located directly above the crankshaft 11 toward the direction opposite to the direction of rotation of the flywheel 2, the convex portion on one side thereof The detecting hole 2a fitted to the position at the rotation angle θ 1 is determined by fitting the detecting means 3 to the concave portion on the other side of -11 - 201043773 to determine the position of the detecting means 3. The state in which the positioning fixture 3a is positioned is fixed by the nut 3b. As described above, it is provided with: the crankshaft 11 of the engine 10 is rotated in parallel with the rotating shaft on the circumference centered on the rotating shaft. The flywheel 2 of the measuring hole 2a is used for detecting detection? [Measuring means 3; and based on the detection signal from the detecting means 3, the engine speed R and the top dead center position TDC1, TDC2 of the piston, and the calculating means 4. With this configuration, no detection error or erroneous detection due to the ring gear or the like does not occur. Thereby, the correct engine speed R and the upper TDC1, TDC2, and TDC3 of the piston can be stably calculated without adding a new detection. The plurality of detecting holes 2a are formed in equiangularly spaced holes, and one of them serves as a blind hole 2b. By making such a configuration, for example, the rigidity of the flywheel 2 can be maintained as compared with the configuration for detecting the hole 2a, and 2a' can correspond to various detecting means by adjusting the depth of the hole. One of the detecting holes 2a is used as the blind hole 2b, so that the position can be easily aligned. In this way, the correct engine speed R and the top dead center position TDC1 TDC3 of the piston can be stabilized without adding new detection means. The detecting means 3' can be carried out by means of a positioning jig 3a in which one side is combined with the detecting hole 2a and the detecting means 3, and the means 3 can be formed by interlocking the fixing member with the "2a". Detect, calculate the means of TDC3 damage, and the non-penetration of the dead point position is the through hole detection hole and the position is calculated by the detection of TDC2, chimerism. -12- 201043773 By making such a configuration, the detecting means 3 can be correctly arranged in accordance with the position of the detecting hole 2a. Thereby, the correct engine speed R and the top dead center positions TDC1, TDC2, and TDC3 of the piston can be stably calculated without adding new detection means. [Industrial Applicability] The present invention can be applied to an engine speed detecting device for calculating an engine speed and a top dead center position of a piston, and is applicable to various engines. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1(a) is a view showing an engine rotation speed detecting device according to an embodiment of the present invention, and Fig. 1(b) is a cross-sectional view taken along line A-A of Fig. 1(a). Fig. 2 is a view showing the configuration of an engine rotation speed detecting device according to an embodiment of the present invention. Q Fig. 3 is a timing chart of the engine rotation speed detecting device according to the embodiment of the present invention. Fig. 4 is a view showing the structure of the detecting means of the engine rotation speed detecting device according to the embodiment of the present invention. [Main component symbol description] 1 : Engine rotation speed detecting device 2 : Flywheel 2a : Detection hole - 13 - 201043773 3 : Detection means 4 : Calculation means 1 1 : Crankshaft TDC 1 : Top dead center position TDC2 : Dead Point position TDC 3: top dead center position R: engine speed 0
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