1231839 (1) 玖、發明說明 【發明所屬之技術領域】 本發明是關於內燃機的吸氣流量控制裝置，特別是關 於能同時達到防止成本上升，且防止對啓動特性的不好影 響的內燃機的吸氣流量控制裝置。 【先前技術】 作爲這種內燃機的吸氣流量控制裝置，一般的習知的 · 方式，是具備有旁通於節流閥，並且具有吸氣控制閥的輔 助吸氣流路。而藉由這種吸氣流量控制裝置，藉由在怠速 時控制該吸氣控制閥的開度，調節流動於輔助吸氣流路的 輔助吸氣流量，則可以配合將引擎轉數作爲目標的怠速轉 數。 在上述吸氣控制閥的開閉驅動時，例如是使用步進馬 達。是把當將該步進馬達配合在基準位置時的閥開度儲存 在電子控制單元（ECU )的記憶體，藉由使對於該基準位 · 置的指令値增減，而可得到任意的閥開度。 在ECU，是藉由檢測引擎轉數等，來決定吸氣控制閥 的目標閥開度（也就是目標輔助吸氣流量），因應於此， 來計算出要供給到步進馬達的指令値。可是，步進馬達經 過時間變化，有時在閥開度會產生誤差。 爲了解決這種誤差，需要週期性地對準基準位置，也 就是說’需要進行使E C U所辨識的吸氣閥控制的閥開度 與實際的閥開度強制性地一致的基準位置定位動作。 -4 - (2) 1231839 根據這種想法，在下述的專利文獻1，是提出了，在 剛將點火開關關閉之後，通電到步進馬達來使吸氣控制閥 移動到全閉位置或全開位置，將該閥位置作爲閥控制的基 準位置。 在下述的專利文獻2，是提出了，在引擎停止之後使 吸氣控制閥移動到半開位置，將該閥位置作爲閥控制的基 準位置。 【專利文獻1】 日本特公昭63 — 42 1 06號公報 【專利文獻2】 日本特開平6 — 3 07267號公報 【發明內容】 〔發明欲解決的課題〕 可是，在上述專利文獻1及2中，由於在引擎停止 時，都需要使步進馬達作動，除了需要輔助ECU的動作 電源的驅動電路之外，需要用來防止電池完全放電，也就 是防止電池沒有電的計時電路等的機能。藉此，會有讓電 路構造複雜化而導致成本上升這樣的問題。 爲了避免這樣的情況，雖然也考慮要在引擎啓動之後 進行吸氣控制閥的基準位置的定位，在這種情況，例如將 全閉位置當作基準位置的話，會由於吸氣流量的不足產生 啓動不良（啓動時間過長，啓動後機器熄火）的情形。而 將全開位置作爲基準位置的話，吸氣流量過大，會讓機器 (3) 1231839 的動作不順暢。 本發明鑑於上述的情形，其目的要提供一種內燃機的 吸氣流量控制裝置，要防止成本上升，且不會對內燃機的 啓動特性造成不好的影響。 〔用以解決課題的手段〕 本發明爲了解決上述課題而採用以下的手段。 第1發明的內燃機的吸氣流量控制裝置，是具備有： φ 旁通於在主吸氣流路中所設置的節流閥的輔助吸氣流路、 以及藉由步進馬達所驅動，用來控制流動於上述輔助吸氣 流路的輔助吸氣流量的輔助吸氣流量控制閥，預先儲存該 輔助吸氣流量控制閥的閥開度及上述輔助吸氣流量間的基 準特性的吸氣流量控制裝置，其特徵爲： 在怠速運轉時， 求出： 目標怠速轉數與現在的怠速轉數之間的差的絕對値， _ 變成比第一臨界値更小的第一改讀條件； 藉由計算來求出用來得到上述目標怠速轉數的上述輔 助吸氣流量的計算吸氣流量、以及根據上述基準特性所求 出的基準吸氣流量間的差的絕對値，變成比第二臨界値更 大的第二改讀條件， 在該第一改讀條件與第二改讀條件同時達成時，會取 代對應於上述計算吸氣流量的閥開度，而進行使用對應於 上述基準特性的上述基準吸氣流量的閥開度的改讀流程。 -6 - (4) 1231839 藉由上述第1發明的內燃機的吸氣流量控制裝置，在 第一改讀條件成立時，會判斷爲現在的怠速轉數接近目標 怠速轉數。在第二改讀條件成立時，則判斷爲輔助吸氣流 量控制閥產生位置偏移需要修正。在同時達成第一改讀條 件及第二改讀條件時，相較於對於計算吸氣流量的閥開 度，是採用對應於基準吸氣流量的閥開度。 第2發明的內燃機的吸氣閥控制裝置，是在內燃機的 吸氣系統設置旁通於節流閥的輔助吸氣流路，並且具備有 連接於步進馬達用來開閉上述輔助吸氣流路的輔助吸氣流 量控制閥的內燃機之吸氣閥控制裝置，其特徵爲：在現在 的怠速轉數接近作爲目標的怠速轉數時，則改讀上述步進 馬達的基準位置。 藉由上述第2發明的內燃機的吸氣閥控制裝置，在現 在的怠速轉數接近作爲目標的怠速轉數時，則改讀步進馬 達的基準位置。 第3發明的內燃機的吸氣閥控制裝置，是在內燃機的 吸热系統設置旁通於節流閥的輔助吸氣流路，並且具備有 連接於步進馬達用來開閉上述輔助吸氣流路的輔助吸氣流 量控制閥的內燃機之吸氣閥控制裝置，其特徵爲：具備 有：用來判斷現在是否爲怠速運轉期間的手段、以及當判 斷現在是在怠速運轉期間時，則執行上述步進馬達的基準 位置改讀動作的手段。 奉昔由上述第3發明的內燃機的吸氣閥控制裝置，當判 斷現在是在怠速運轉期間時，則執行步進馬達的基準位置 1231839 (5) 改讀動作。 【實施方式】 以下一邊參照圖面一邊說明本發明的內燃機的吸氣流 β ί空制裝置的一實施方式，當然本發明並沒有限定於此。 在本實施方式中，雖然是以將本發明適用在機車的例子來 i兌明’而當然本發明也可適用於其他車輛。 如第1圖及第2圖所示，本實施方式的機車1，是將 鲁 雙人座墊的座墊2兼作爲蓋子，且在前後較長的置物箱3 的正下方配置有動力單元4的速克達型機車。動力單元 4，是具備有：將氣缸體6大幅度前傾的引擎（內燃機） 5、以及相對於該引擎5的曲軸箱9的其中一側，一體地 連接朝後方延伸的變速箱1 〇的無段變速機8，在變速箱 1 0的後端部是軸支承著後輪（驅動輪）1 1。 如第2圖所示，在接合於上述氣缸體6的前端的氣缸 頭7，是設置有：將上流端朝向車體後方開口的吸氣口 · 7a、以及朝向該吸氣口 7a的下流端噴射燃料的燃料噴射 閥7 b。並且，在吸氣口 7 a的上流端’是連接著用來控制 供給到引擎5的吸氣流量的吸氣流量控制裝置2 1。 如第3圖所示，該吸氣流量控制裝置21，是具備 有：具有連通到上述吸氣口 7a的主吸氣流路32a的節流 閥3 1、以及具有迂迴於該節流閥3 1的輔助吸氣流路42a 的怠速閥4 1 ° 節流閥3 1，如第2圖及第3圖所示，是具備有：在 (6) 1231839 內部形成有主吸氣流路3 2 a的筒狀的節流閥主體3 2、設 置在該節流閥主體32的內部用來開閉主吸氣流路32a的 節流閥3 3、以及用來將驅動力傳達到該節流閥3 3的驅動 力傳達機構（沒有圖示）。在節流閥主體3 的上流端， 是經由吸氣導管22連接著空氣濾淸器23。而節流閥主體 3 2的下流端，是經由連接管2 3而被連接在上述氣缸頭 7。在節流閥主體3 2的側壁部，是形成有：連通於較節流 閥33更上流側的主吸氣流路32a的旁通入口 32b、以及 φ 連通於較節流閥33更下流側的主吸氣流路32a的旁通出 口 32c 〇 怠速閥4 1，是具備有：相對於節流閥主體3 2被固定 爲一體的盒體46、形成在該盒體46內，藉由在節流閥主 體32外使旁通入口 32b及旁通出口 32c連通而旁通（迂 迴）於節流閥3 3的上述輔助吸氣流路4 2、用來控制流動 於該輔助吸氣流路4 2的輔助吸氣流量的旁通閥（輔助吸 氣流量控制閥）4 3、用來驅動該旁通閥4 3的步進馬達 · 4 4、將該步進馬達4 4的旋轉驅動力變換成旁通閥4 3的進 退驅動力的動力傳達部4 5、以及用來控制步進馬達4 4的 電子控制單元（沒有圖示，以下稱作E C U )。 在盒體46，是形成有：連通於旁通入口 32b的輔助 吸氣入口 46a、連通於旁通出口 32c的輔助吸氣出口 46b、以及使該輔助吸氣入口 46a與輔助吸氣出口 46b之 間連通，並且插入旁通閥4 6的閥孔4 6 c。 旁通閥43 ’具備有：具有略中空圓筒形狀，形成於 -9 - (7) 1231839 其前端的弟一閥孔4 3 a、以及形成在側壁，連通於第一閥 孔43a的第二閥孔43b與第三閥孔43c。該旁通閥43，當 於閥孔46c內進行進退動作時，藉由當第二閥孔43b與第 三閥孔43c與輔助吸氣出口 46b重疊時所形成的連通流路 的剖面積的大小，來控制輔助吸氣流量。於是，因應閥孔 4 6c內的旁通閥43的進退位置，則可控制對引擎5的輔 助吸氣流量。 也就是說，如第4圖的左下圖所示，在啓動引擎的狀 鲁 態，爲了將對引擎5的吸氣流量調整到最大，會讓第二閥 孔43b與第三閥孔43c的全開口面積與輔助吸氣出口 46b 的開口面積重疊。藉此，如同圖上的圖表所示，將怠速閥 4 1的開度（IA CV開度）調整到最大，則可以讓引擎轉數 (ENG轉數）上升。 在啓動後的暖機運轉，如第4圖的中央下圖所示，是 使第三閥孔43c、與第二閥孔43b的其中一部分連通於輔 助吸氣出口 46b。藉此，如同圖上的曲線圖所示，則可以 β 將怠速閥4 1的開度（I AC V開度）調節成暖機運轉時的閥 開度。 並且，在該暖機運轉後的怠速運轉，如第4圖的右下 圖所示，會使第二閥孔43b完全關閉並且僅將第三閥孔 43c連通於輔助吸氣出口 46b。藉此，如同圖上的圖表所 示，.就可以將怠速閥41的開度（IACV開度）調節成怠速 運轉時的閥開度。 如第3圖所示，步進馬達4 4，是以與閥孔4 6 c同軸 - 10 - (8) 1231839 的方式被固定在盒體4 1內，在其旋轉軸44a形成有公螺 紋4 4 a 1。圖號4 7是密封構件，是用來防止輔助吸氣流路 42內的吸氣從閥孔46c朝向外部洩漏。 動力傳達部45，是具備有：具有螺合於旋轉軸44 a 的母螺紋孔45al的驅動構件45a、以及用來將旁通閥43a 固定在該驅動構件45a的彈簧45b。在驅動構件45a與旁 通閥4 3之間是中介著十字聯軸節4 5，可朝向將其軸線作 爲中心的直徑方向進行相對位移。彈簧45b，是用來將旁 φ 通閥4 3相對於形成在驅動構件4 5 a的鍔部4 5 a2進行彈壓 的彈壓構件，則可無搖晃地相對於驅動構件45a固定住旁 通閥4 3。 上述ECU，是用來控制步進馬達44的步驟數的構 造，是儲存著：用來求出大氣壓修正係數的大氣壓圖表、 根據冷卻引擎5的冷卻水的溫度來決定輔助吸氣流量的水 溫圖表（參照第5圖（a )。啓動時，對準每次行駛的各 運轉模式）、用來決定旁通閥43的閥開度與輔助吸氣流 · 量間的基準特性（也就是，當將步進馬達44對準到基準 位置時的步驟位置與質量流量之間的特性）的基準質量流 量圖表（參照第5圖（b )的粗線，橫軸的「IACV開度」 表示閥開度。）、以及當得到體積流量時，顯示需要的步 進馬達4 4的步驟位置的體積流量圖表。 該E C U，也可讀取以沒有圖示的大氣壓感應器所測定 的大氣壓値、或冷卻水的水溫。 以下，參照第6圖〜第8圖來針對以上所說明的吸氣 - 11 - (9) 1231839 流量控制裝置2 1 (以下稱作IACV )的控制流程來加以說 明。第6圖是顯示同控制流程的槪要，第7圖及第8圖是 顯示附屬於第6圖所示的控制流程的副程序。在以下的說 明中，怠速轉數爲INE，引擎的目標轉數爲目標NE。而 在怠速轉數中，該時間所求出的怠速轉數爲這一次INE， 在這一次的之前一個步驟所求得的怠速轉數爲上一次 INE，利用實際測量所求得的現狀的怠速轉數爲現狀NE， 之前一個步驟所求得的怠速轉數爲上一次NE。 (1 )步驟S 1的流程 當將點火啓動開始進行IACV的控制時，首先在步驟 S1會求出大氣壓修正係數。也就是說，如第7圖（a)的 副程序所示，在步驟S 1 — 1，參照儲存在ECu的上述大 氣壓圖表，來計算出對應於以上述大氣壓感應器所測定的 大氣壓値的大氣壓修正係數。在求出大氣壓修正係數之 後，當在啓動時或行駛時，會進入到第6圖的步驟S 2。 當在怠速運轉時，會進入到第6圖的步驟S 3。 (2 )步驟S 2的流程 當進入到步驟S 2時，會求出在啓動時或行駛中的吸 氣的質量流量。也就是說，如第7圖（b )所示，在啓動 時會進入到步驟S2 — 1，在ECU的上述各水溫圖表中’ 會參照啓動時的水溫圖表，計算出對應於以上述水溫感應 器所測定的水溫的啓動時質量流量。另一方面，在行駛 -12- (10) 1231839 時，會進入到步驟S2 - 2，在ECU的上述各水溫圖表 中，參照行駛中用的上述水溫圖表，計算出對應於以上述 水溫感應器所測定的水溫的行駛中質量流量。求出了啓動 時或行駛中的吸氣的質量流量之後’會跳過第6圖的步驟 S 3而進入到步驟S 4。 (3 )步驟S 3的流程 進入到步驟S 3時，會求出怠速運轉所需要的質量流 · 量。也就是說，如第7圖（c )所示，在步驟S 3 — 1，計 算出作爲所測定的現狀NE與目標NE的差的絕對値的誤 差。接著在步驟S 3 - 2中，計算出作爲現狀NE與上一次 NE的差的絕對値的差分△ NE。接下來在步驟S 3 — 3，根 據在步驟S3 — 1、S3 - 2中分別求出的上述誤差及差分△ NE，來計算出PID質量流量。接著在步驟S3 — 4，藉由將 以步驟S3- 3所算出的PID質量流量加在對應於上一次 INE的質量流量，來算出對應於這一次INE的INE質量流 . 量。在求出現狀INE質量流量之後，進入到第6圖的步驟 S4 ° (4 )步驟S 4的流程 在該步驟S4，會對應於在步驟S2所求出的啓動時或 行駛時的質量流量、或對應於在步驟S3所求出的怠速運 轉時的質量流量（INE質量流量），來求出馬達的步驟位 置。也就是說，如第8圖（a )所示，首先，在步驟4 一 1 -13- (11) 1231839 判斷是否爲啓動時。當爲啓動時，則進入到步驟4 - 2， 藉由使用在步驟S 1 - 1所求出的大氣壓修正係數來將啓動 時的質量流量進行大氣壓修正，計算出啓動時的體積流 量。接著在步驟S 4 - 3，參照儲存在E C U的上述體積流 量圖表，計算出對應於在步驟S4 - 2所求出的啓動時體積 流量的目標步驟位置。在求出目標步驟位置之後，會跳過 第6圖的步驟S 5而進入到步驟S 6。 另一方面，當在步驟S4 - 1判斷不是在啓動時的情 春 況，在步驟S4 - 4會判斷是否在行駛中。當判斷是在行駛 中的情況，會進入到步驟S45，當判斷是在怠速運轉時’ 則進入到步驟S4 — 7。 當進入到步驟S4 — 5時，藉由使用在步驟S 1 — 1所求 出的大氣壓修正係數來將行駛中的質量流量進行大氣壓修 正，計算出行駛中體積流量。接著在步驟S4 - 6，會參照 在ECU所儲存的上述體積流量圖表，計算出對應於在步 驟S 4 — 5所求出的行駛中體積流量的目標步驟位置。在求 麵 出目標步驟位置之後，會跳過第6圖的步驟S 5而進入到 步驟S 6。 另一方面，當在步驟S 4 - 4判斷不是在行駛中的情 況，會當作在怠速運轉中而進入到步驟4 一 7。藉由使用 在步驟S 1 - 1所求出的大氣壓修正係數來將怠速運轉質量 流量（INE質量流量）進行大氣壓修正，計算出怠速體積 流量（INE體積流量）。接著在步驟S4 — 8，會參照在 ECU所儲存的上述體積流量圖表，計算出對應於在步驟 -14 - (12) 1231839 S4 — 7所求出的怠速體積流量的目標步驟位置。在求出目 標步驟位置之後，會進入到第6圖的步驟以。 (5 )步驟S 5的流程 在該步驟S 5中，當下述的第一改讀條件與第二改讀 條件同時達成時，會進行上述步進馬達44的基準位置的 改讀。也就是’當現在的怠速轉數接近作爲目標的怠速轉 數時，會改g買步進馬達4 4的基準位置（藉由判斷現在是馨 否爲怠速運轉的手段也就是E C U，當判斷現在爲怠速運轉 時，則執行步進馬達4 4的基準位置的改讀動作。）。 更g羊細來I兌’如桌8圖（b )所示，首先在步驟S 5 — 1 ’當判斷爲以步驟S 3 — 1所求得的上述誤差（目標怠速 轉數、與以脈衝感應器所檢測的現在的怠速轉數的差的絕 對値）較預定的臨界値更小的情況，則當作第一改讀條件 成立而進入到步驟 S 5 - 2。在第一改讀條件不成立的情 況，則不會進行改讀而進入到第6圖的步驟S 6。 春 在進入到步驟S 5 - 2的情況，藉由使用以步驟S 1 - 1 所求出的大氣壓修正係數，來將ECU內的上述基準質量 流量圖表進行大氣壓修正’計算出基準體積流量。接著在 步驟S5— 3，參照ECU內的上述體積流量圖表，計算出 對應於以步驟S 5 - 2所求出的基準體積流量的目標步驟位 置a。接著在步驟S5 - 3a’會從上述體積流里0表舁出 INE體積流量相當的目標步驟位置b。 接著在步驟S 5 — 4中，計算出：以步驟S 5 - 3所求出 -15- (13) 1231839 的目標步驟位置a、與以步驟S 5 一 3 a所求出的目標步驟 位置b的差的絕對値，在判斷該値較預定的臨界値（第二 臨界値）更大的情況，則會進入到步驟S 5 - 5，在判斷爲 較小的情況，則會進入到第6圖的步驟S 6。也就是說， 在該步驟S 5 — 4，當藉由計算來求出用來得到目標怠速轉 數的輔助吸氣流量時的計算吸氣流量、與根據上述基準質 量流量圖表（基準特性）所求出的基準吸氣流量的差的絕 對値，較第二臨界値更大時，則當作達成第二改讀條件而 · 進入到步驟S 6。 當進入到步驟S 5 - 5時，會將以步驟S 5 — 3 a所求出 的目標步驟位置，改讀成以步驟S 5 - 3所求出的目標步驟 位置。 也就是說，會將計算所求出的目標步驟位置b (對應 於計算吸氣流量的閥開度）改讀成根據上述基準質量流量 圖表所求出的基準步驟位置a (對應於基準特性上的基準 吸氣流量的閥開度）。更詳細來說，如第5圖（b )所 鲁 示，在IACV開度從實線所示的工廠出貨時的閥特性，由 於時間的變化而平行地變成虛線所示的閥特性的情況，取 代以計算來求出用來得到相同空氣流量的IACV開度（步 驟位置）的方式，採用從工廠出貨時的閥特性所求出的 IACV開度。例如在同圖的例子中，以計算所求出的IACV 開度是ST2，而將其取代成ST1。藉此，即使閥特性產生 誤差，也可用軟體加以修正。在實施目標步驟位置的改讀 之後，進入到第6圖的步驟S 6。 -16 - (14) 1231839 (6 )步驟S 6的流程 在步驟S 6中，會在對應於所求得的目標步驟位置的 步驟位置驅動步進馬達44。也就是說，如第8圖（c )所 示，在步驟S6 - 1，參照在上述步驟S4 — 3、S4 - 6、S4 一 8的其中一個所求出的目標步驟位置、或是步驟S 5 - 5 改讀的目標步驟値，藉由使步進馬達44旋轉，來得到目 標閥開度（也就是確保作爲目標的輔助吸氣流量。）。 如以上的說明，本實施方式的吸氣流量控制裝置 2 1，在判斷現在的怠速轉數接近目標怠速轉數，且判斷旁 通閥43產生位置誤差需要基準位置定位時，相較於對於 計算吸氣流量的閥開度，會改讀對應於基準吸氣流量的閥 開度作爲較正確的閥開度。 藉由這種構造，除了在引擎5停止時就不需要進行基 準位置定位，在引擎5停止時不需要用來輔助動作電源的 驅動電路之外，也不需要用來防止電池沒電的計時電路。 藉此，可防止電路構造複雜化且可防止成本上升。而在基 準位置定位時，不需要強制性地將旁通閥4 3全閉或全 開，所以也能防止啓動不良或劇烈的車輛動作。 於是，可防止成本上升且可同時防止對啓動特性的不 好影響。 〔發明效果〕 第1發明的內燃機之吸氣流量控制裝置，在進行輔助 -17- (15) 1231839 吸氣流量控制閥的基準位置定位時，在同時達成：目標怠 速轉數與現在的S、速轉數之間的差的絕對値，變成比第一* 臨界値更小的第一改讀條件、以及計算吸氣流量與基準吸 氣流量間的差的絕對値，變成比第二臨界値更大的第二改 讀條件的情況，會取代對應於計算吸氣流量的閥開度，而 進行使用對應於基準特性的基準吸氣流量的閥開度的改讀 流程。 藉由這種構造，除了在內燃機停止時就不需要進行基 φ 準位置定位，在內燃機停止時不需要用來輔助動作電源的 驅動電路之外，也不需要用來防止電池沒電的計時電路。 藉此，可防止電路構造複雜化且可防止成本上升。而在基 準位置定位時，不需要強制性地將輔助吸氣流量控制閥全 閉或全開，所以也能防止啓動不良。 藉由本發明，可防止成本上升且可同時防止對啓動特 性的不好影響。 藉由本發明的第2發明與第3發明的內燃機之進氣閥 肇 控制裝置，可得到與上述第1發明的內燃機的進氣流量控 制裝置同樣的效果。 【圖式簡單說明】 第1圖是顯示具備有本發明的內燃機的吸氣流量控制 裝置的機車的一實施方式的側面圖。 第2圖是同機車的主要部分的顯示圖，是第1圖的A 部放大剖面圖。 -18- (16) 1231839 第3圖是顯示同機車的吸氣流量控制裝置的槪略構造 的說明圖。 第4圖是用來說明同吸氣流量控制裝置的動作的說明 圖。 第5圖是儲存在同吸氣流量控制裝置的ECU的圖表 的顯示圖，（a )是顯示在某水溫用來得到預定引擎轉數 的空氣流量的水溫圖表’ （b )是顯示旁通閥的開度、與 該時間所流動的輔助吸氣流量的關係的基準質量流量圖 鲁 表，實線是工廠出貨時的閥特性’虛線是相對於工廠出貨 而平行地偏移的閥特性。 第6圖是顯示同吸氣流量控制裝置的控制流程的說明 圖。 第7圖是同吸氣流量控制裝置的控制流程的局部詳細 情形的顯示圖，（a )〜（c )是顯示第6圖的步驟S 1〜 S 3的各副程序。 第8圖是同吸氣流量控制裝置的控制流程的局部詳細 · 情形的顯示圖，（a )〜（c )是顯示第6圖的步驟S4〜 S 6的各副程序。 【圖號說明】 3 2a :主吸氣流路 3 3 ’·節流閥 42 :輔助吸氣流路 4 3 :旁通閥（輔助吸氣流量控制閥） -19 - (17)1231839 4 4 :步進馬達1231839 (1) 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to an intake flow control device for an internal combustion engine, and more particularly to an internal combustion engine that can simultaneously prevent cost increase and prevent an adverse effect on starting characteristics of the internal combustion engine. Air flow control device. [Prior Art] As an intake flow control device of such an internal combustion engine, a conventionally known method is to provide an auxiliary intake air flow path bypassing a throttle valve and having an intake control valve. With this intake flow control device, by controlling the opening degree of the intake control valve at idle speed, and adjusting the auxiliary intake flow flowing through the auxiliary intake flow path, it is possible to cooperate with the engine revolution number as the target. Idle speed. When the intake control valve is opened and closed, a stepping motor is used, for example. The valve opening when the stepping motor is fitted in the reference position is stored in the memory of the electronic control unit (ECU). By increasing or decreasing the command for the reference position and position, an arbitrary valve can be obtained. Opening degree. In the ECU, the target valve opening degree (that is, the target auxiliary intake flow rate) of the intake control valve is determined by detecting the number of revolutions of the engine, and the command 値 to be supplied to the stepping motor is calculated accordingly. However, when the stepping motor changes over time, an error may occur in the valve opening degree. In order to solve such an error, it is necessary to periodically align the reference position, that is, it is necessary to perform a reference position positioning operation that forcibly matches the valve opening degree controlled by the intake valve recognized by ECu with the actual valve opening degree. -4-(2) 1231839 According to this idea, in the following Patent Document 1, it is proposed that immediately after the ignition switch is turned off, the stepping motor is energized to move the intake control valve to the fully closed position or the fully open position. Use this valve position as the reference position for valve control. Patent Document 2 described below proposes moving the intake control valve to a half-open position after the engine is stopped, and using this valve position as a reference position for valve control. [Patent Document 1] Japanese Patent Publication No. 63-42 1 06 [Patent Document 2] Japanese Patent Application Laid-Open No. 6-3 07267 [Summary of the Invention] [Problems to be Solved by the Invention] However, in the aforementioned Patent Documents 1 and 2 Because the stepping motor needs to be activated when the engine is stopped, in addition to the driving circuit that needs to assist the ECU's operating power, it needs to prevent the battery from completely discharging, that is, to prevent the battery from running out of time. As a result, there is a problem that the circuit structure is complicated and the cost increases. In order to avoid such a situation, it is also considered that the reference position of the intake control valve is positioned after the engine is started. In this case, for example, if the fully closed position is used as the reference position, the start may occur due to insufficient intake flow. Defective (too long startup time, machine shuts down after startup). If the fully open position is used as the reference position, the intake air flow will be too large, which will cause the machine (3) 1231839 to malfunction. The present invention has been made in view of the above circumstances, and an object thereof is to provide an intake flow control device for an internal combustion engine to prevent cost increase without adversely affecting the starting characteristics of the internal combustion engine. [Means for Solving the Problems] The present invention employs the following measures in order to solve the problems described above. The intake flow control device for an internal combustion engine according to the first invention is provided with: an auxiliary intake air flow path bypassing a throttle valve provided in the main intake air flow path; The auxiliary inspiratory flow control valve for controlling the auxiliary inspiratory flow rate flowing through the auxiliary inspiratory flow path, and stores in advance the valve opening degree of the auxiliary inspiratory flow control valve and the inspiratory flow rate with reference characteristics between the auxiliary inspiratory flow rate. The control device is characterized in that during the idling operation, the absolute absolute value of the difference between the target idling speed and the current idling speed is obtained, and _ becomes the first rereading condition which is smaller than the first critical value; The absolute value 差 of the difference between the calculated inspiratory flow rate for obtaining the auxiliary inspiratory flow rate for obtaining the target idle speed and the reference inspiratory flow rate obtained from the reference characteristics is calculated to be second critical.値 A larger second rereading condition, when the first rereading condition and the second rereading condition are achieved at the same time, it will replace the valve opening corresponding to the above-mentioned calculated intake flow rate, and use the corresponding corresponding to the above-mentioned reference characteristics. The reading process of the valve opening degree of the above-mentioned reference intake flow rate. -6-(4) 1231839 With the intake flow control device for an internal combustion engine of the first invention described above, when the first read condition is satisfied, it is determined that the current idle speed is close to the target idle speed. When the second rereading condition is established, it is determined that the positional deviation of the auxiliary suction air flow control valve needs to be corrected. When the first rewriting condition and the second rewriting condition are achieved at the same time, the valve opening degree corresponding to the reference intake flow rate is adopted compared to the valve opening degree for calculating the intake flow rate. The intake valve control device for an internal combustion engine of a second invention is provided with an auxiliary intake air path bypassing a throttle valve in an intake system of the internal combustion engine, and is provided with a stepping motor for opening and closing the auxiliary intake air path. The intake valve control device of an internal combustion engine that assists the intake air flow control valve is characterized in that when the current idle speed is close to the target idle speed, the reference position of the stepping motor is re-read. With the intake valve control device for an internal combustion engine of the second invention described above, when the current idle speed is close to the target idle speed, the reference position of the stepping motor is rewritten. A third aspect of the invention is an intake valve control device for an internal combustion engine, which is provided with an auxiliary intake air path bypassing a throttle valve in an endothermic system of the internal combustion engine, and is provided with a stepping motor for opening and closing the auxiliary intake air path. The intake valve control device of an internal combustion engine that assists the intake air flow control valve is characterized by having a means for determining whether it is an idling operation period and performing the above steps when it is judged that it is an idling operation period. Means to read the reference position of the motor. In the past, the intake valve control device of the internal combustion engine according to the third invention described above, when it is judged that it is during the idling operation, executes the reference position of the stepper motor 1231839 (5) Read operation. [Embodiment] An embodiment of the air intake device β of the internal combustion engine of the present invention will be described below with reference to the drawings. Of course, the present invention is not limited to this. In this embodiment, although the present invention is applied to a locomotive as an example, it is obvious that the present invention is also applicable to other vehicles. As shown in FIG. 1 and FIG. 2, the locomotive 1 of this embodiment uses the seat cushion 2 of the Lu double seat cushion as a cover, and the power unit 4 is arranged directly below the storage box 3 that is long in the front and rear. Scooter locomotive. The power unit 4 is provided with an engine (internal combustion engine) 5 that tilts the cylinder block 6 substantially forward, and a gearbox 1 extending rearwardly is integrally connected to one side of a crankcase 9 of the engine 5. The stepless transmission 8 has a rear wheel (driving wheel) 11 supported at the rear end of the transmission 10. As shown in FIG. 2, the cylinder head 7 connected to the front end of the cylinder block 6 is provided with an intake port 7a that opens the upstream end toward the rear of the vehicle body, and a downstream end that faces the intake port 7a. Fuel injection valve 7b for injecting fuel. An upstream end of the intake port 7a is connected to an intake flow rate control device 21 for controlling an intake flow rate supplied to the engine 5. As shown in FIG. 3, the intake flow control device 21 is provided with a throttle valve 31 having a main intake air path 32a communicating with the intake port 7a, and a bypass valve 3 As shown in Figures 2 and 3, the idle speed valve 4 1 of the auxiliary suction flow path 42a of 1 is provided with a throttle valve 31, and a main suction flow path 3 2 is formed in (6) 1231839. a cylindrical throttle body 3 2, a throttle body 3 provided inside the throttle body 32 to open and close the main suction air path 32a, and a driving force to be transmitted to the throttle body 3 3 driving force transmission mechanism (not shown). An air filter 23 is connected to the upstream end of the throttle body 3 via an intake duct 22. The downstream end of the throttle body 32 is connected to the cylinder head 7 through a connecting pipe 23. The side wall portion of the throttle body 32 is formed with a bypass inlet 32b communicating with the main intake air flow path 32a on the upstream side from the throttle valve 33 and φ communicating with the downstream side from the throttle valve 33 The bypass outlet 32c of the main intake air flow path 32a is provided with a case 46 that is integrally fixed to the throttle body 32, and is formed in the case 46. The outside of the throttle body 32 communicates with the bypass inlet 32b and the bypass outlet 32c and bypasses (detours) the auxiliary suction flow path 4 3 of the throttle valve 3 2 for controlling the flow through the auxiliary suction flow path 4 2 Bypass valve for auxiliary suction flow (auxiliary suction flow control valve) 4 3. Stepping motor to drive the bypass valve 4 3 4 4 Rotary driving force of the stepping motor 4 4 A power transmission unit 45 that converts the forward and backward driving force of the bypass valve 43 and an electronic control unit (not shown, hereinafter referred to as ECU) for controlling the stepping motor 44. The box body 46 is formed with an auxiliary intake inlet 46a communicating with the bypass inlet 32b, an auxiliary intake outlet 46b communicating with the bypass outlet 32c, and one of the auxiliary intake inlet 46a and the auxiliary intake outlet 46b. And the valve hole 4 6 c of the bypass valve 46 is inserted. The bypass valve 43 ′ has a slightly hollow cylindrical shape and is formed at -9-(7) 1231839 at the front end of the first valve hole 4 3 a and a second hole formed in the side wall and communicating with the first valve hole 43 a The valve hole 43b and the third valve hole 43c. When the bypass valve 43 moves forward and backward in the valve hole 46c, the size of the cross-sectional area of the communication flow path formed when the second valve hole 43b, the third valve hole 43c, and the auxiliary suction outlet 46b overlap with each other. To control the auxiliary inspiratory flow. Therefore, in accordance with the advance and retreat positions of the bypass valve 43 in the valve hole 46c, the auxiliary intake air flow to the engine 5 can be controlled. In other words, as shown in the lower left diagram of FIG. 4, in order to adjust the intake air flow to the engine 5 to the maximum when the engine is started, the entirety of the second valve hole 43 b and the third valve hole 43 c are adjusted. The opening area overlaps with the opening area of the auxiliary suction outlet 46b. With this, as shown in the graph on the figure, by adjusting the opening degree of the idle valve 41 (IA CV opening degree) to the maximum, the number of engine revolutions (ENG revolutions) can be increased. After the start-up warm-up operation, as shown in the lower center of FIG. 4, a part of the third valve hole 43c and the second valve hole 43b are communicated with the auxiliary suction outlet 46b. Thereby, as shown in the graph on the figure, the opening degree (I AC V opening degree) of the idling valve 41 can be adjusted to the valve opening degree during warm-up operation. In addition, during the idling operation after the warm-up operation, as shown in the lower right of Fig. 4, the second valve hole 43b is completely closed and only the third valve hole 43c is communicated with the auxiliary intake outlet 46b. Thereby, as shown in the graph on the figure, the opening degree of the idle valve 41 (IACV opening degree) can be adjusted to the valve opening degree during idle operation. As shown in FIG. 3, the stepping motor 4 4 is fixed in the box body 4 1 coaxially with the valve hole 4 6 c-10-(8) 1231839, and a male thread 4 is formed on its rotating shaft 44a. 4 a 1. Reference numeral 47 is a sealing member for preventing the suction air in the auxiliary suction air flow path 42 from leaking from the valve hole 46c to the outside. The power transmission unit 45 includes a driving member 45a having a female screw hole 45al screwed to the rotation shaft 44a, and a spring 45b for fixing the bypass valve 43a to the driving member 45a. A cross coupling 45 is interposed between the driving member 45a and the bypass valve 43, and can be relatively displaced in a diameter direction with its axis as the center. The spring 45b is an elastic member for elastically pressing the bypass φ port valve 4 3 against the crotch portion 4 5 a2 formed on the driving member 4 5 a, so that the bypass valve 4 can be fixed to the driving member 45a without shaking. 3. The ECU has a structure for controlling the number of steps of the stepping motor 44 and stores an atmospheric pressure chart for obtaining an atmospheric pressure correction coefficient, and a water temperature for determining the auxiliary intake flow rate based on the temperature of the cooling water of the cooling engine 5 Graph (refer to Fig. 5 (a). At the time of starting, the driving mode is aligned with each operation mode), and the reference characteristic for determining the valve opening degree of the bypass valve 43 and the auxiliary suction air flow amount (that is, A reference mass flow chart (refer to the thick line in Fig. 5 (b) when the stepping motor 44 is aligned to the reference position) (refer to the thick line in Fig. 5 (b), and the horizontal axis "IACV opening" indicates the valve Opening degree.), And when the volume flow rate is obtained, a volume flow rate chart showing the step position of the required stepping motor 44 is displayed. This E C U can also read the atmospheric pressure 値 measured by an atmospheric pressure sensor (not shown) or the water temperature of the cooling water. In the following, the control flow of the inhalation-11-(9) 1231839 flow control device 2 1 (hereinafter referred to as IACV) will be described with reference to Figs. 6 to 8. Fig. 6 shows the outline of the control flow, and Figs. 7 and 8 show the subroutines attached to the control flow shown in Fig. 6. In the following description, the idle speed is INE, and the target speed of the engine is target NE. Among the idling revolutions, the idling revolutions obtained at this time is the INE this time, and the idling revolutions obtained in the previous step of this time is the previous INE. The actual idling speed obtained from the actual measurement is used. The number of revolutions is the current NE, and the number of idle revolutions obtained in the previous step is the last NE. (1) The flow of step S1 When the ignition is started and the IACV control is started, the atmospheric pressure correction coefficient is first obtained in step S1. That is, as shown in the subroutine of FIG. 7 (a), in step S 1-1, the atmospheric pressure corresponding to the atmospheric pressure 値 measured by the atmospheric pressure sensor is calculated by referring to the atmospheric pressure map stored in the ECu. Correction factor. After the atmospheric pressure correction coefficient is obtained, the process proceeds to step S2 in FIG. 6 when starting or driving. When the vehicle is idling, the process proceeds to step S3 in FIG. 6. (2) The flow of step S 2 When the process proceeds to step S 2, the mass flow rate of the inhaled air at the time of starting or running is obtained. In other words, as shown in FIG. 7 (b), the process proceeds to step S2-1 at the time of startup. In the above-mentioned water temperature graphs of the ECU, the water temperature graphs at the time of startup are referred to and calculated to correspond to the above-mentioned The mass flow rate at the start of the water temperature measured by the water temperature sensor. On the other hand, when driving -12- (10) 1231839, it will proceed to step S2-2. In the above-mentioned water temperature graphs of the ECU, referring to the above-mentioned water temperature graphs used during travel, the calculation corresponding to the above-mentioned water The mass flow rate during driving with the water temperature measured by the temperature sensor. After the mass flow rate of the intake air at the time of starting or running is obtained ', step S3 in FIG. 6 is skipped and the process proceeds to step S4. (3) Flow of step S 3 When proceeding to step S 3, the mass flow and volume required for idling are obtained. That is, as shown in FIG. 7 (c), in step S3-1, the error which is the absolute difference between the measured current NE and the target NE is calculated. Next, in step S 3-2, a difference ΔNE which is an absolute value of the difference between the current NE and the previous NE is calculated. Next, in steps S 3-3, PID mass flow is calculated based on the above errors and differences Δ NE obtained in steps S 3-1 and S 3-2 respectively. Then, in steps S3-4, the PID mass flow rate calculated in step S3-3 is added to the mass flow rate corresponding to the previous INE to calculate the INE mass flow rate corresponding to the current INE. After the appearance INE mass flow rate is obtained, the process proceeds to step S4 ° (4) in FIG. 6. The flow of step S 4 in this step S4 corresponds to the mass flow rate at start-up or travel obtained in step S2, Alternatively, the step position of the motor is obtained corresponding to the mass flow rate (INE mass flow rate) during the idling operation obtained in step S3. That is, as shown in FIG. 8 (a), first, it is determined whether or not it is a start-up at step 4-1 -13- (11) 1231839. When it is started, it proceeds to step 4-2, and uses the atmospheric pressure correction coefficient obtained in step S1-1 to perform atmospheric pressure correction on the mass flow rate at startup, and calculates the volume flow rate at startup. Then, in step S4-3, referring to the above-mentioned volume flow chart stored in ECU, a target step position corresponding to the volumetric flow rate at start-up obtained in step S4-2 is calculated. After the target step position is obtained, step S5 in FIG. 6 is skipped and the process proceeds to step S6. On the other hand, when it is judged in step S4-1 that it is not at the time of start-up, it is judged in step S4-4 whether it is running. When it is determined that the vehicle is running, the process proceeds to step S45, and when it is determined that the vehicle is idling, the process proceeds to step S4-7. When the process proceeds to steps S4-5, the mass flow rate during travel is corrected by using the atmospheric pressure correction coefficient obtained in step S1-1, and the volume flow rate during travel is calculated. Then in step S4-6, the target step position corresponding to the volume flow rate during driving calculated in step S4-5 will be calculated by referring to the volume flow chart stored in the ECU. After the target step position is found, step S5 in FIG. 6 is skipped and the process proceeds to step S6. On the other hand, if it is determined in step S 4-4 that the vehicle is not running, it will proceed to step 4-7 as if it is idling. The idling volume flow (INE mass flow) is corrected for atmospheric pressure by using the atmospheric pressure correction coefficient obtained in step S 1-1 to calculate the idling volume flow (INE volume flow). Then in step S4-8, the target step position corresponding to the idle volume flow rate obtained in steps -14-(12) 1231839 S4-7 will be calculated by referring to the volume flow chart stored in the ECU. After finding the position of the target step, you will proceed to the step in Figure 6. (5) Flow of step S5 In this step S5, when the following first rewriting condition and the second rewriting condition are satisfied at the same time, the reference position of the stepping motor 44 is rewritten. That is, when the current idle speed is close to the target idle speed, the reference position of the stepper motor 4 4 will be changed (by determining whether the current speed is idling or ECU, which is the ECU, when determining the current speed In the idling operation, the reference position reading operation of the stepping motor 44 is executed.). As shown in Figure 8 (b) of Table 8, first, when it is judged that the above error (the target idling revolutions and the pulse If the absolute difference between the current idling revolutions detected by the sensor is smaller than a predetermined threshold, the first read condition is satisfied, and the process proceeds to step S 5-2. In the case where the first rereading condition is not satisfied, the process proceeds to step S6 in FIG. 6 without performing the rereading. In the case of proceeding to step S 5-2, the reference volume flow rate is calculated by using the atmospheric pressure correction coefficient obtained in step S 1-1 to perform atmospheric pressure correction on the reference mass flow rate graph in the ECU. Then, in step S5-3, referring to the volume flow chart in the ECU, a target step position a corresponding to the reference volume flow obtained in step S5-2 is calculated. Next, in step S5-3a ', the target step position b with the equivalent INE volume flow rate is indicated from the above-mentioned volume flow. Then in steps S 5-4, calculate: the target step position a of -15- (13) 1231839 obtained in step S 5-3 and the target step position b obtained in step S 5-3 a If the absolute absolute value of the difference is larger than the predetermined critical value (the second critical value), the process proceeds to step S 5-5. If the absolute value of the difference is small, the process proceeds to step 6 Step S 6 of the figure. In other words, in this step S 5-4, when the auxiliary intake flow rate for obtaining the target idle speed is obtained by calculation, the calculated intake flow rate is calculated from the reference mass flow rate chart (reference characteristic). When the absolute value 差 of the difference of the reference intake flow rate obtained is larger than the second critical value ，, it is deemed that the second rewriting condition has been reached and the process proceeds to step S6. When step S 5-5 is entered, the target step position obtained in step S 5-3 a will be read into the target step position obtained in step S 5-3. In other words, the calculated target step position b (corresponding to the valve opening degree for calculating the intake flow rate) is rewritten to the reference step position a (corresponding to the reference characteristic) obtained from the above reference mass flow rate chart. Valve opening of the reference suction flow). In more detail, as shown in FIG. 5 (b), when the valve characteristics when the IACV opening degree is shipped from the factory shown by the solid line, the valve characteristics shown by the dotted line are changed in parallel due to the change in time. Instead of calculating the IACV opening degree (step position) for obtaining the same air flow rate, the IACV opening degree obtained from the valve characteristics at the time of shipment from the factory is used. For example, in the example in the same figure, the calculated IACV opening degree is ST2, and it is replaced with ST1. In this way, even if the valve characteristics are incorrect, they can be corrected by software. After rewriting the target step position, the process proceeds to step S6 in FIG. 6. -16-(14) 1231839 (6) Flow of step S6 In step S6, the stepping motor 44 is driven at the step position corresponding to the obtained target step position. That is, as shown in FIG. 8 (c), in step S6-1, referring to the target step position obtained in one of steps S4-3, S4-6, and S4-8, or step S, 5-5 Rereading the target step 値 The target valve opening degree is obtained by rotating the stepping motor 44 (that is, ensuring the target auxiliary suction flow rate.). As described above, the inhalation flow control device 21 according to this embodiment judges that the current idle speed is close to the target idle speed and determines that the position error of the bypass valve 43 requires the reference position positioning. The valve opening degree of the intake flow rate will read the valve opening degree corresponding to the reference intake flow rate as a more accurate valve opening degree. With this structure, in addition to the need for reference position positioning when the engine 5 is stopped, a drive circuit to assist the operating power source is not required when the engine 5 is stopped, and a timing circuit to prevent the battery from running out is not required. . Thereby, it is possible to prevent the circuit structure from being complicated and increase the cost. When positioning in the reference position, it is not necessary to fully close or fully open the bypass valve 43, so it is possible to prevent poor starting or severe vehicle movement. Therefore, it is possible to prevent an increase in cost and at the same time prevent an adverse influence on the starting characteristics. [Effects of the Invention] When the intake flow control device of the internal combustion engine of the first invention is assisted in positioning the reference position of the intake flow control valve, the target idle speed and the current S, The absolute value of the difference between the speeds becomes the first rereading condition smaller than the first * critical value, and the absolute value of the difference between the calculated inspiratory flow rate and the reference inspiratory flow rate becomes the second critical value. In the case of a larger second read condition, a process of reading the valve opening degree corresponding to the reference intake flow rate corresponding to the reference characteristic is performed instead of the valve opening degree corresponding to the calculated intake flow rate. With this structure, in addition to the base φ quasi-position positioning is not required when the internal combustion engine is stopped, the drive circuit to assist the operating power is not required when the internal combustion engine is stopped, and the timer circuit is not required to prevent the battery from running out. . Thereby, it is possible to prevent the circuit structure from being complicated and increase the cost. When positioning at the reference position, it is not necessary to fully close or fully open the auxiliary suction flow control valve, so it can prevent poor starting. With the present invention, it is possible to prevent an increase in cost and at the same time prevent a bad influence on the starting characteristics. According to the second and third inventions of the intake valve actuation control device of the internal combustion engine, it is possible to obtain the same effects as those of the intake flow control device of the internal combustion engine of the first invention. [Brief Description of Drawings] Fig. 1 is a side view showing an embodiment of a locomotive provided with an intake flow rate control device for an internal combustion engine of the present invention. FIG. 2 is a display diagram of a main part of the same locomotive, and is an enlarged cross-sectional view of part A of FIG. 1. -18- (16) 1231839 Fig. 3 is an explanatory diagram showing a schematic structure of an intake flow control device for a locomotive. Fig. 4 is an explanatory diagram for explaining the operation of the same inspiratory flow control device. Fig. 5 is a display diagram of a chart of an ECU stored in the same intake flow rate control device. (A) is a water temperature chart showing an air flow rate at a certain water temperature for obtaining a predetermined engine revolution. (B) is a display side The reference mass flow chart for the relationship between the opening of the valve and the auxiliary intake flow rate flowing at that time. The solid line is the valve characteristics at the time of shipment from the factory. The dotted line is shifted parallel to the factory shipment. Valve characteristics. Fig. 6 is an explanatory diagram showing a control flow of the same suction flow rate control device. Fig. 7 is a partial detailed view of the control flow of the inhalation flow control device, and Figs. (A) to (c) are subroutines showing steps S1 to S3 of Fig. 6. Fig. 8 is a partial detailed view of the control flow of the same inhalation flow control device. Figs. 8 (a) to (c) are subroutines showing steps S4 to S6 of Fig. 6. [Illustration of drawing number] 3 2a: Main suction air flow path 3 3 '· throttle valve 42: Auxiliary suction air flow path 4 3: Bypass valve (auxiliary suction flow control valve) -19-(17) 1231839 4 4 : Stepping motor
-20--20-