內(nèi)燃機的燃油供應(yīng)系統(tǒng)[中文3374字] 【中英文WORD】

內(nèi)燃機的燃油供應(yīng)系統(tǒng)[中文3374字] 【中英文WORD】,中文3374字,中英文WORD,內(nèi)燃機的燃油供應(yīng)系統(tǒng)[中文3374字],【中英文WORD】,內(nèi)燃機,燃油,供應(yīng),系統(tǒng),中文,3374,中英文,WORD Fuel Supply System For An Internal Combustion Engine Abstract A pulsation damper is provided between and in series with a low pressure fuel system pipe and a high pressure pump of a fuel supply system. During startup of an engine,low pressure fuel supplied via the low pressure fuel system pipe is injected from an intake passage fuel injector. When the fuel pressure is equal to or less than a fuel pressure at which good startability can be maintained,the pulsation damper closes off communication between the high pressure fuel system pipe and the low pressure fuel system pipe using the spring force of a spring. Key words: Fuel supply system; An internal combustion engine ;A pulsation damper; A low pressure fuel system pipe and a high pressure pump; A fuel supply system for an internal combustion engine,comprising: a low pressure pump that is capable to pressurize fuel; a low pressure fuel supply passage that is capable to supply fuel that was pressurized by the low pressure pump to a low pressure fuel injection mechanism which injects fuel into an intake passage; a branch passage that branches off from the low pressure fuel supply passage and through which the fuel that was pressurized by the low pressure pump flows; a high pressure pump which is capable to pressurize the fuel supplied via the branch passage,the high pressure pump being driven by the internal combustion engine; a high pressure fuel supply passage that is capable to supply fuel that was pressurized by the high pressure to a high pressure fuel injection mechanism which injects fuel into a cylinder; and a pulsation reducing mechanism provided on an intake side of the high pressure pump,wherein,when the internal combustion engine is started by only injecting fuel from the low pressure supply passage into the intake passage,the pulsation reducing mechanism closes off communication between the low pressure fuel supply passage and the high pressure fuel supply passage until a pressure of fuel in the low pressure fuel supply passage reaches a predetermined pressure value required for starting the internal combustion engine. Background of the invention : 1. Field of the Invention The invention relates to a fuel supply system for an internal combustion engine provided with a fuel injection mechanism that injects fuel at high pressure into a cylinder (i.e.; a fuel injector for in-cylinder injection,hereinafter referred to as “in-cylinder fuel injector”) and a fuel injection mechanism that injects fuel into an intake passage or an intake port (i.e.,a fuel injector for intake passage injection,hereinafter referred to as “intake passage fuel injector”). More particularly,the invention relates to a fuel supply system that can improve startability of an internal combustion engine. 2. Description of the Related Art A gasoline engine is known which is provided with a fast fuel injection valve for injecting fuel into a combustion chamber of the engine (i.e.,an in-cylinder fuel injector) and a second fuel injection valve for injecting fuel into an intake passage (i.e.,an intake passage fuel injector),and divides the injected fuel between the in-cylinder fuel injector and the intake passage fuel injector according to the engine speed and engine load. Also,a direct injection gasoline engine is also known which is provided with only a fuel injection valve for injecting fuel into the combustion chamber of the engine (i.e.,an in-cylinder fuel injector). In a high pressure fuel system that includes an in-cylinder fuel injector,fuel of which the pressure has been increased by a high pressure fuel pump is supplied to the in-cylinder fuel injector via a delivery pipe. The in-cylinder fuel injector then injects the high pressure fuel into the combustion chamber of each cylinder of the internal combustion engine. In addition,a diesel engine is also known which has a common rail type fuel injection system. In this common rail type fuel injection system,fuel which has been increased in pressure by a high pressure fuel pump is stored in a common rail. The high pressure fuel is then injected into the combustion chamber of each cylinder of the diesel engine from the common rail by opening and closing an electromagnetic valve. In order to increase the pressure of (i.e.,pressurize) the fuel in this kind of internal combustion engine,a high pressure fuel pump is provided which is driven by a cam provided on a driveshaft that is connected to a crankshaft of the internal combustion engine. Japanese Patent Application Publication No. JP-A-2005-139923 describes a high pressure fuel supply system for an internal combustion engine that can reduce vibrational noise when only a small amount of fuel is required by the internal combustion engine,such as during idling,while being able to deliver the necessary amount of fuel over the entire operating range of the internal combustion engine. This high pressure fuel supply system for an internal combustion engine has a two single plunger type high pressure fuel pumps each of which have a spill valve that spills fuel drawn into a pressurizing chamber that is divided by a cylinder and a plunger that moves back and forth in the cylinder,from that pressurizing chamber. When fuel is pressurized and delivered from the pressurizing chamber to the high pressure fuel system,the amount of fuel delivered is adjusted by controlling the spill valve open and closed. One of these high pressure fuel pumps is a first high pressure fuel pump in which the lift amount of the plunger is small and the other high pressure fuel pump is a second high pressure fuel pump in which the lift amount of the plunger is large. In addition to these two high pressure fuel pumps,the high pressure fuel supply system for an internal combustion engine also includes control means. The control means controls the spill valve of each high pressure fuel pump according to the amount of fuel required by the internal combustion engine,such that fuel is pressurized and delivered using only the first high pressure fuel pump when the amount of required fuel is small,and fuel is pressurized and delivered using at least the second high pressure fuel pump when the amount of required fuel is large. According to this high pressure fuel supply system for an internal combustion engine,of the two high pressure fuel pumps,the first high pressure fuel pump has a plunger with a small lift amount so the rate of pressure increase is small and a large amount of water hammer is also self-suppressed. That is,with the high pressure fuel supply system,the vibrational noise produced when the required fuel quantity is small can be preferably reduced by controlling the spill valve of each of the high pressure fuel pumps so that only the first high pressure fuel pump is used when the amount of fuel required for the internal combustion engine is small such as during idling. On the other hand,the second high pressure fuel pump has a plunger with a large lift amount so pressurizing and delivering fuel using at least this second high pressure fuel pump also makes it possible to deliver the required fuel quantity when the amount of fuel required by the internal combustion engine increases to the point where it can no longer be delivered by the first high pressure fuel pump alone. That is,providing two high pressure fuel pumps having plungers with different lift amounts in this way enables the required amount of fuel to be delivered throughout the entire operating range of the internal combustion engine,while reducing vibrational noise when the amount of required fuel is small. In Japanese Patent Application Publication No. JP-A-2005-139923,the high pressure fuel supply system for a V-type 8 cylinder internal combustion engine having an in-cylinder fuel injector in each cylinder is provided with a high pressure fuel pump for each bank. Tip ends that branch off from a low pressure fuel passage which is connected to the fuel tank are connected to galleries of these high pressure fuel pumps. For each bank,a pulsation damper is provided midway between the branch portion of the low pressure fuel passage and the portion that connects with the gallery. This pulsation damper suppresses the pulsation in the fuel pressure in the low pressure fuel passage when the high pressure fuel pump is operating. At engine startup in this kind of a direct injection engine having only an in-cylinder fuel injector,fuel is unable to be delivered by the high pressure fuel pump until the engine turns over. Therefore,low pressure fuel is delivered by a feed pump to the fuel injection for in-cylinder injection. Therefore,the pulsation damper is designed to provide communication between the high pressure pipe system and the low pressure pipe system. For example,FIG. 6 is a sectional view of such a pulsation damper 215 ,FIG. 7 is a sectional view taken along line VII-VII of FIG. 6 ,and FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7. As shown in FIGS. 6 to 8,grooves 223 A,223 B,223 C,and 223 D are provided in an end face (i.e.,the upper surface in FIG. 8) that abuts against a contacting member 226 A of the pulsation damper 215 . Therefore,when the feed pressure is low,the spring 226 D presses the contacting member 226 A against the upper surface of the member that forms the inlet 222 and the outlet 224 . In this way,the structure is such that even if pressure is applied by the spring 226 D,the grooves 223 A,223 B,223 C,and 223 D enable fuel delivered from the inlet 222 (i.e.,the feed pump side) to flow into the outlet 224 (i.e.,the high pressure fuel pump side) as shown by the dotted line in FIG. 8. On the other hand,as described above,an engine is known which includes,for each cylinder,an in-cylinder fuel injector that injects fuel into a combustion chamber of the engine and an intake passage fuel injector that injects fuel into an intake passage. In this engine,fuel is injected divided between the in-cylinder fuel injector and the intake passage fuel injector according to the engine speed and the load on the internal combustion engine. This engine is also provided with the pulsation damper shown in FIGS. 6 to 8. However,in this kind of engine,the following problems occur when starting the engine by injecting fuel with an intake passage fuel injector. When fuel is delivered by a feed pump at engine startup,the volume of pipe that needs to be charged with fuel becomes significantly larger. That is,when the engine is started with fuel injected from the intake passage fuel injector,despite the fact that fuel can be delivered to the intake passage fuel injector with the feed pump by simply charging only the low pressure pipe with fuel,the pulsation damper is structured such that the high pressure pipe system and the low pressure pipe system are communicated or open to one another. Therefore,fuel is unable to be delivered to the intake passage fuel injector by the feed pump unless both the low pressure pipe and the high pressure pipe are charged with fuel. As a result,it takes time for the feed pressure to rise,thereby adversely affecting startability (i.e.,increasing the start time). Summary of the invention This invention thus provides a fuel supply system for an internal combustion engine,which is capable of improving startability of an internal combustion engine that includes a fuel injection mechanism for injecting fuel at high pressure into a cylinder (i.e.,in-cylinder fuel injector) and a fuel injecting mechanism for injecting fuel into an intake passage or an intake port (i.e.,an intake passage fuel injector). A first aspect of the invention relates to a fuel supply system for an internal combustion engine which includes a low pressure fuel supply passage that supplies fuel that was pressurized by a low pressure pump to a low pressure fuel injection mechanism which injects fuel into an intake passage; a branch passage that branches off from the low pressure fuel supply passage and supplies fuel to a high pressure pump that is driven by the internal combustion engine; a high pressure fuel supply passage that supplies fuel that was pressurized by the high pressure pump to a high pressure fuel injection mechanism which injects fuel into a cylinder; and a pulsation reducing mechanism provided on the intake side of the high pressure pump. The pulsation reducing mechanism closes off communication between the low pressure fuel supply passage and the high pressure fuel supply passage when a pressure of fuel in the low pressure fuel supply passage is lower than a predetermined value. According to this first aspect,the high pressure pump which is driven by the internal combustion engine does not operate during startup of the internal combustion engine. In this case,the internal combustion engine is started by injecting fuel that has been pressurized by the low pressure pump from the low pressure fuel injection mechanism via the low pressure fuel supply passage. In this case,during startup of the internal combustion engine when the pressure of fuel in the low pressure fuel supply passage is low,the pulsation reducing mechanism closes off communication between the low pressure fuel supply passage and the high pressure fuel supply passage. Therefore,fuel can be delivered to the low pressure fuel injection mechanism simply by charging the low pressure fuel supply passage with fuel using the low pressure pump. Accordingly,there is no need to charge the high pressure fuel supply passage with fuel using the low pressure pump so the low pressure fuel supply passage and the branch passage that provides communication between the low pressure fuel supply passage and the high pressure pump can be charged with fuel quickly,and fuel can be quickly injected from the low pressure fuel injection mechanism. As a result,startability of an internal combustion engine provided with a fuel injection mechanism that injects fuel at high pressure into the cylinder and a fuel injection mechanism that injects fuel into the intake passage or intake port can be improved. 內(nèi)燃機的燃油供應(yīng)系統(tǒng) 摘 要 在低壓燃油供應(yīng)系統(tǒng)管道和燃油供應(yīng)系統(tǒng)的高壓泵之間有一系列的有節(jié)奏的脈動衰減節(jié)氣閥。在發(fā)動機啟動的階段，通過低壓燃油系統(tǒng)管道，低壓燃油從一燃油噴射機中被噴入。當(dāng)燃油的壓力與維持發(fā)動機在穩(wěn)定狀態(tài)時所需的燃油壓力相同時或稍低時，此時有節(jié)奏的脈動衰減節(jié)氣閥，在彈簧的彈力作用下關(guān)閉了高壓燃油系統(tǒng)管道與低壓燃油系統(tǒng)管道之間的通路。 關(guān)鍵詞：內(nèi)燃機；燃油供應(yīng)系統(tǒng)；脈動衰減節(jié)氣閥；低壓燃油供應(yīng)系統(tǒng)管道和高壓泵。 內(nèi)燃機的燃油供系統(tǒng)，包括：一臺能給燃油加壓的低壓油泵、一個能供應(yīng)低壓油泵所加壓的燃油通道，同時能把燃油輸送到低壓燃油抵押燃油噴射機構(gòu)的入口處；一個分岔來自上面低壓燃油供應(yīng)通道、并且流經(jīng)分支通道的燃油在流經(jīng)低壓燃油泵時被加壓；一臺能給通過上面的分支通道供應(yīng)的低壓燃油進行加壓的高壓油泵，這臺高壓燃油泵通過內(nèi)燃機而驅(qū)動；高壓燃油供應(yīng)通道能夠?qū)⑷加蛧娙肫椎母邏喝加蛧娚錂C構(gòu)提供被加壓的燃油；同時一個有規(guī)律的衰減機構(gòu)本安裝在高壓泵入口的一側(cè)，在哪兒，當(dāng)內(nèi)燃機啟動的時候，噴射入口處的燃油僅僅來自低壓燃油供應(yīng)通道，此時這個有規(guī)律衰減機構(gòu)經(jīng)低壓燃油供應(yīng)通道與高壓燃油供應(yīng)通道之間的通道關(guān)閉，直到低壓燃油供應(yīng)通道中的燃油壓力達到了內(nèi)燃機開始要求所預(yù)定的壓力值時才開啟。 發(fā)明背景 1.發(fā)明的領(lǐng)域 這個發(fā)明是關(guān)于為內(nèi)燃機燃油供應(yīng)系統(tǒng)提供一個將燃油在較高壓力下將其噴入汽缸的燃油噴射機構(gòu)（汽缸內(nèi)燃油噴射，在下文涉及的是“缸內(nèi)燃油噴射”）和一個將燃油噴入進口通道或端口噴射的燃油噴射機構(gòu)（進口通道燃油噴射，在下文提到的“進口燃油噴射”）。尤其是這個發(fā)明所關(guān)于的燃油噴射供應(yīng)系統(tǒng)能提高內(nèi)燃機的工作穩(wěn)定性。 2.相關(guān)技術(shù)的介紹 眾所周知，汽油機配備了一個將燃油快速噴入發(fā)動機燃燒室的燃油噴射閥和一個將燃油快速噴入進氣管道的二次燃油噴射閥（進氣管道燃油噴射器）。區(qū)分在汽缸內(nèi)燃油噴射和進氣管道燃油噴射是依據(jù)發(fā)動機的速度和負荷。同時我們知道，直噴式汽油機僅僅配備了一個將燃油噴入發(fā)動機燃燒室的燃油噴射閥（汽缸內(nèi)燃油噴射器）。在一個包括汽缸內(nèi)燃油噴射器的高壓燃油的高壓燃油系統(tǒng)中，被高壓油泵所加壓的燃油通過一個傳送管道而被供應(yīng)到汽缸內(nèi)燃油噴射器中。然后，這個汽缸內(nèi)燃油噴射將高壓燃油噴入內(nèi)燃機每個汽缸的燃燒室中。 總而言之，我們知道柴油機有一個共同的橫桿類型的燃油噴射系統(tǒng)，在這個共同的橫桿類型的燃油噴射系統(tǒng)中，被高壓油泵所加壓的燃油被存儲在共同的橫桿中。通過電磁閥的開啟和關(guān)閉將共同橫桿中的高壓燃油噴射到柴油機的每個汽缸的燃燒室中。 為了增加這種類型內(nèi)燃機的燃油壓力，提供了一種與內(nèi)燃機的曲軸相連的凸輪推桿所驅(qū)動的高壓燃油泵。 日本申請的專利號為：JP-A-2005-139923的專利介紹了一個當(dāng)內(nèi)燃機所需燃油的數(shù)量很少時，能減少針對噪聲的內(nèi)燃機高壓燃油供應(yīng)系統(tǒng)。例如，待機時，能將必要數(shù)量輸送到內(nèi)燃機的全部工作領(lǐng)域。這種內(nèi)燃機的高壓燃油供應(yīng)有一個有兩個獨立柱塞式的高壓燃油泵，他們中有一個溢流閥將溢流出的燃油吸取到被一個汽缸和在汽缸中前后移動的柱塞所分開的壓力室中，當(dāng)燃油從壓力室中加壓和輸送到高壓燃油系統(tǒng)時，燃油輸送的數(shù)量是通過控制溢流閥的開啟和關(guān)閉來調(diào)整的。在這些高壓燃油泵之一的是在首次高壓燃油泵中提起的柱塞的量很小，另外一個高壓燃油泵是一個二次高壓燃油泵，在其中說提起的柱塞的量較大。總之在這兩個高壓燃油泵中，內(nèi)燃機的高壓燃油供應(yīng)系統(tǒng)中包括了控制方式。這種控制每個高壓油泵的溢流閥的控制方式是依據(jù)內(nèi)燃機所需燃油量，如當(dāng)所需燃油量較少時，燃油的加壓和輸送僅使用一次高壓油泵；當(dāng)所需燃油較大時，燃油的加壓和輸送，則要使用二次高壓油泵。 依據(jù)這種內(nèi)燃機的高壓燃油供應(yīng)系統(tǒng)，兩個高壓燃油泵，一次高壓燃油泵有一個提升量較小的柱塞，以致于壓力增加速度較慢。那就是，有了這個高壓燃油供應(yīng)系統(tǒng)，當(dāng)所需燃油數(shù)量較少時所產(chǎn)生的振動噪聲能夠通過控制高壓燃油泵的溢流閥得到很好的降低，以致于當(dāng)內(nèi)燃機所需的燃油量較小，如待機時，只要一次高壓燃油泵工作。在另一方面，二次高壓油泵有一個提升量較大的柱塞，因而其壓力和輸送量在二次高壓油泵下，可能輸送到內(nèi)燃機所需燃油的增加處，而這卻是在單依靠一次高壓油泵的輸送是不可能完成的。在這種方法下適當(dāng)數(shù)量的燃油被輸送到內(nèi)燃機的整個工作領(lǐng)域，從而當(dāng)所需燃油量小時，能減小振動噪聲。 在日本專利局申請的專利號為：JP-A-2005-139923，一個型號為V-8內(nèi)燃機高壓燃油供應(yīng)系統(tǒng)中有一個缸內(nèi)噴射器，在每一個汽缸中配備了一個高壓油泵。與燃油箱相連的低壓燃油通道分支的末端被連接到這些高壓油泵的端口上。對每一油泵組，脈動衰減節(jié)流閥被安裝在低壓燃油通道的分支部與連接端口部分的中間處。當(dāng)高壓油泵工作時，這個脈動衰減節(jié)流閥迫使在低壓燃油通道中的燃油壓力跳動。在發(fā)動機啟動時，這種直噴發(fā)動機僅僅有一個缸內(nèi)燃油噴射器，燃油不能通過高壓燃油輸送，直到發(fā)動機運動。因此，低壓燃油通過一個裝置泵輸送到燃油噴射處進行缸內(nèi)噴射。因此，脈動衰減節(jié)流閥被設(shè)計成提供高壓管道系統(tǒng)與低壓管道之間的溝通。例如，圖6是這樣的脈動阻尼器215剖視圖。圖7是一個截面視圖沿線七至圖6，圖8是沿線剖面圖第八至圖7。在圖所示，圖6至8，溝槽223A，223B，223C和D是在底面（即在圖8上表面提供的）表示，對一個緊靠一個聯(lián)系的脈動阻尼器215和226。因此，當(dāng)進給壓力低時，彈簧226D按下一個與226A相聯(lián)系，構(gòu)成進222和224的插座上表面。其這樣的結(jié)構(gòu)是，即使壓力是由彈簧226D應(yīng)用，溝槽223A，223B，223C和223D使燃料從222入口（即給水泵端）交付流入出口224（即高壓燃油泵方如在圖虛線所示），即圖8。 另一方面，如上所述，一個是已知的，其中包括發(fā)動機，每個汽缸，在汽缸燃油噴射器的注入一個發(fā)動機燃燒室的燃料和燃料噴射器的進氣通道的攝入量是通過注入燃料。在這個引擎，注入在汽缸噴油器和燃料噴射器之間的燃料的劃分是根據(jù)發(fā)動機的轉(zhuǎn)速和內(nèi)燃發(fā)動機的負荷。這款發(fā)動機的脈動阻尼器如圖所示6至8。 然而，在這種發(fā)動機中產(chǎn)生了接下來的一些問題。當(dāng)通過進氣管道燃油噴射器噴射燃油啟動發(fā)動機時。當(dāng)在發(fā)動機啟動時通過一個裝置泵輸送燃油時，需要被用于索取燃油的管道的容積變成十分大。那樣的話，當(dāng)發(fā)動機從進氣通道燃油噴射器噴入的燃油而啟動，盡管事實是燃油能通過在低壓油管道中的裝置泵將燃油輸送到進氣管燃油噴射器中，脈動衰減節(jié)流閥被構(gòu)造成將高壓管道系統(tǒng)與低壓管道系統(tǒng)之一溝通或打開。因此，燃油不可能通過裝置泵輸送到進口通道燃油噴射器中，除非低壓管道與高壓管道都被用于索取燃油。由于這樣的結(jié)果，它需要時間緩慢地提高壓力，因此，反而影響了穩(wěn)定性（增加了啟動時間）。 發(fā)明總結(jié) 這個發(fā)明因此為內(nèi)燃機提供了一個燃油供應(yīng)系統(tǒng)，其能提高由將燃油在較高壓力下將燃油噴入汽缸的燃油噴射機構(gòu)（缸內(nèi)燃油噴射）和將燃油噴入進氣通道或進氣端口的燃油噴射機構(gòu)（進氣通道燃油噴射）組成的內(nèi)燃機的穩(wěn)定性。 一方面這個發(fā)明涉及了內(nèi)燃機燃油供應(yīng)系統(tǒng)，其包括了一個供應(yīng)被低壓油泵所加壓的燃油的低壓供應(yīng)通道，并且將其送到進氣通道燃油噴射的地壓燃油噴射機構(gòu)中去；一個分支來自低壓燃油供應(yīng)通道的岔口，并且將燃油供應(yīng)到被內(nèi)燃機所驅(qū)動的高壓油泵中；一個供應(yīng)被高壓油泵所加壓的燃油的高壓供應(yīng)通道，并且將其送到汽缸內(nèi)燃油噴射的高壓燃油噴射機構(gòu)中；在高壓油泵的靠近進氣道的一側(cè)安裝了脈動衰減機構(gòu)，這個脈動衰減機構(gòu)關(guān)閉了低壓燃油供應(yīng)通道和高壓燃油供應(yīng)通道之間的溝通，當(dāng)?shù)蛪喝加凸?yīng)通道中的燃油壓力低于預(yù)先設(shè)定的值時。 依據(jù)第一方面的情況，在內(nèi)燃機啟動階段，這個被內(nèi)燃機所驅(qū)動的高壓泵不能工作，在這種情況下，內(nèi)燃機通過噴射被來自低壓燃油噴射機構(gòu)的低壓泵所加壓的經(jīng)過低壓燃油供應(yīng)通道的燃油而啟動。在這種情況下，在內(nèi)燃機的啟動階段，考慮到低壓燃油供應(yīng)通道中的燃油壓力較低，脈動衰減機構(gòu)關(guān)閉了低壓燃油通道與高壓燃油通道之間的通路。因此，燃油只有使用低壓燃油泵將低壓燃油供應(yīng)通道中的燃油輸送到低壓燃油噴射機構(gòu)中去。相應(yīng)地，這里不需要高壓燃油供應(yīng)通道去供油，而用低壓油泵，也就是說提供低壓燃油供油通道和高壓泵之間通道的低壓燃油供應(yīng)通道和分支通道。能夠快速索取燃油，同時燃油能夠快速地從低壓燃油噴射機構(gòu)中噴出。因此，配備了將燃油在較高壓力下將燃油噴入汽缸的燃油噴射機構(gòu)和將燃油噴入進氣通道或進氣端口的內(nèi)燃機的穩(wěn)定能夠被提高。