内燃机的燃油供应系统[中文3374字] 【中英文WORD】

内燃机的燃油供应系统[中文3374字] 【中英文WORD】,中文3374字,中英文WORD,内燃机的燃油供应系统[中文3374字],【中英文WORD】,内燃机,燃油,供应,系统,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. 内燃机的燃油供应系统 摘 要 在低压燃油供应系统管道和燃油供应系统的高压泵之间有一系列的有节奏的脉动衰减节气阀。在发动机启动的阶段，通过低压燃油系统管道，低压燃油从一燃油喷射机中被喷入。当燃油的压力与维持发动机在稳定状态时所需的燃油压力相同时或稍低时，此时有节奏的脉动衰减节气阀，在弹簧的弹力作用下关闭了高压燃油系统管道与低压燃油系统管道之间的通路。 关键词：内燃机；燃油供应系统；脉动衰减节气阀；低压燃油供应系统管道和高压泵。 内燃机的燃油供系统，包括：一台能给燃油加压的低压油泵、一个能供应低压油泵所加压的燃油通道，同时能把燃油输送到低压燃油抵押燃油喷射机构的入口处；一个分岔来自上面低压燃油供应通道、并且流经分支通道的燃油在流经低压燃油泵时被加压；一台能给通过上面的分支通道供应的低压燃油进行加压的高压油泵，这台高压燃油泵通过内燃机而驱动；高压燃油供应通道能够将燃油喷入汽缸的高压燃油喷射机构提供被加压的燃油；同时一个有规律的衰减机构本安装在高压泵入口的一侧，在哪儿，当内燃机启动的时候，喷射入口处的燃油仅仅来自低压燃油供应通道，此时这个有规律衰减机构经低压燃油供应通道与高压燃油供应通道之间的通道关闭，直到低压燃油供应通道中的燃油压力达到了内燃机开始要求所预定的压力值时才开启。 发明背景 1.发明的领域 这个发明是关于为内燃机燃油供应系统提供一个将燃油在较高压力下将其喷入汽缸的燃油喷射机构（汽缸内燃油喷射，在下文涉及的是“缸内燃油喷射”）和一个将燃油喷入进口通道或端口喷射的燃油喷射机构（进口通道燃油喷射，在下文提到的“进口燃油喷射”）。尤其是这个发明所关于的燃油喷射供应系统能提高内燃机的工作稳定性。 2.相关技术的介绍 众所周知，汽油机配备了一个将燃油快速喷入发动机燃烧室的燃油喷射阀和一个将燃油快速喷入进气管道的二次燃油喷射阀（进气管道燃油喷射器）。区分在汽缸内燃油喷射和进气管道燃油喷射是依据发动机的速度和负荷。同时我们知道，直喷式汽油机仅仅配备了一个将燃油喷入发动机燃烧室的燃油喷射阀（汽缸内燃油喷射器）。在一个包括汽缸内燃油喷射器的高压燃油的高压燃油系统中，被高压油泵所加压的燃油通过一个传送管道而被供应到汽缸内燃油喷射器中。然后，这个汽缸内燃油喷射将高压燃油喷入内燃机每个汽缸的燃烧室中。 总而言之，我们知道柴油机有一个共同的横杆类型的燃油喷射系统，在这个共同的横杆类型的燃油喷射系统中，被高压油泵所加压的燃油被存储在共同的横杆中。通过电磁阀的开启和关闭将共同横杆中的高压燃油喷射到柴油机的每个汽缸的燃烧室中。 为了增加这种类型内燃机的燃油压力，提供了一种与内燃机的曲轴相连的凸轮推杆所驱动的高压燃油泵。 日本申请的专利号为：JP-A-2005-139923的专利介绍了一个当内燃机所需燃油的数量很少时，能减少针对噪声的内燃机高压燃油供应系统。例如，待机时，能将必要数量输送到内燃机的全部工作领域。这种内燃机的高压燃油供应有一个有两个独立柱塞式的高压燃油泵，他们中有一个溢流阀将溢流出的燃油吸取到被一个汽缸和在汽缸中前后移动的柱塞所分开的压力室中，当燃油从压力室中加压和输送到高压燃油系统时，燃油输送的数量是通过控制溢流阀的开启和关闭来调整的。在这些高压燃油泵之一的是在首次高压燃油泵中提起的柱塞的量很小，另外一个高压燃油泵是一个二次高压燃油泵，在其中说提起的柱塞的量较大。总之在这两个高压燃油泵中，内燃机的高压燃油供应系统中包括了控制方式。这种控制每个高压油泵的溢流阀的控制方式是依据内燃机所需燃油量，如当所需燃油量较少时，燃油的加压和输送仅使用一次高压油泵；当所需燃油较大时，燃油的加压和输送，则要使用二次高压油泵。 依据这种内燃机的高压燃油供应系统，两个高压燃油泵，一次高压燃油泵有一个提升量较小的柱塞，以致于压力增加速度较慢。那就是，有了这个高压燃油供应系统，当所需燃油数量较少时所产生的振动噪声能够通过控制高压燃油泵的溢流阀得到很好的降低，以致于当内燃机所需的燃油量较小，如待机时，只要一次高压燃油泵工作。在另一方面，二次高压油泵有一个提升量较大的柱塞，因而其压力和输送量在二次高压油泵下，可能输送到内燃机所需燃油的增加处，而这却是在单依靠一次高压油泵的输送是不可能完成的。在这种方法下适当数量的燃油被输送到内燃机的整个工作领域，从而当所需燃油量小时，能减小振动噪声。 在日本专利局申请的专利号为：JP-A-2005-139923，一个型号为V-8内燃机高压燃油供应系统中有一个缸内喷射器，在每一个汽缸中配备了一个高压油泵。与燃油箱相连的低压燃油通道分支的末端被连接到这些高压油泵的端口上。对每一油泵组，脉动衰减节流阀被安装在低压燃油通道的分支部与连接端口部分的中间处。当高压油泵工作时，这个脉动衰减节流阀迫使在低压燃油通道中的燃油压力跳动。在发动机启动时，这种直喷发动机仅仅有一个缸内燃油喷射器，燃油不能通过高压燃油输送，直到发动机运动。因此，低压燃油通过一个装置泵输送到燃油喷射处进行缸内喷射。因此，脉动衰减节流阀被设计成提供高压管道系统与低压管道之间的沟通。例如，图6是这样的脉动阻尼器215剖视图。图7是一个截面视图沿线七至图6，图8是沿线剖面图第八至图7。在图所示，图6至8，沟槽223A，223B，223C和D是在底面（即在图8上表面提供的）表示，对一个紧靠一个联系的脉动阻尼器215和226。因此，当进给压力低时，弹簧226D按下一个与226A相联系，构成进222和224的插座上表面。其这样的结构是，即使压力是由弹簧226D应用，沟槽223A，223B，223C和223D使燃料从222入口（即给水泵端）交付流入出口224（即高压燃油泵方如在图虚线所示），即图8。 另一方面，如上所述，一个是已知的，其中包括发动机，每个汽缸，在汽缸燃油喷射器的注入一个发动机燃烧室的燃料和燃料喷射器的进气通道的摄入量是通过注入燃料。在这个引擎，注入在汽缸喷油器和燃料喷射器之间的燃料的划分是根据发动机的转速和内燃发动机的负荷。这款发动机的脉动阻尼器如图所示6至8。 然而，在这种发动机中产生了接下来的一些问题。当通过进气管道燃油喷射器喷射燃油启动发动机时。当在发动机启动时通过一个装置泵输送燃油时，需要被用于索取燃油的管道的容积变成十分大。那样的话，当发动机从进气通道燃油喷射器喷入的燃油而启动，尽管事实是燃油能通过在低压油管道中的装置泵将燃油输送到进气管燃油喷射器中，脉动衰减节流阀被构造成将高压管道系统与低压管道系统之一沟通或打开。因此，燃油不可能通过装置泵输送到进口通道燃油喷射器中，除非低压管道与高压管道都被用于索取燃油。由于这样的结果，它需要时间缓慢地提高压力，因此，反而影响了稳定性（增加了启动时间）。 发明总结 这个发明因此为内燃机提供了一个燃油供应系统，其能提高由将燃油在较高压力下将燃油喷入汽缸的燃油喷射机构（缸内燃油喷射）和将燃油喷入进气通道或进气端口的燃油喷射机构（进气通道燃油喷射）组成的内燃机的稳定性。 一方面这个发明涉及了内燃机燃油供应系统，其包括了一个供应被低压油泵所加压的燃油的低压供应通道，并且将其送到进气通道燃油喷射的地压燃油喷射机构中去；一个分支来自低压燃油供应通道的岔口，并且将燃油供应到被内燃机所驱动的高压油泵中；一个供应被高压油泵所加压的燃油的高压供应通道，并且将其送到汽缸内燃油喷射的高压燃油喷射机构中；在高压油泵的靠近进气道的一侧安装了脉动衰减机构，这个脉动衰减机构关闭了低压燃油供应通道和高压燃油供应通道之间的沟通，当低压燃油供应通道中的燃油压力低于预先设定的值时。 依据第一方面的情况，在内燃机启动阶段，这个被内燃机所驱动的高压泵不能工作，在这种情况下，内燃机通过喷射被来自低压燃油喷射机构的低压泵所加压的经过低压燃油供应通道的燃油而启动。在这种情况下，在内燃机的启动阶段，考虑到低压燃油供应通道中的燃油压力较低，脉动衰减机构关闭了低压燃油通道与高压燃油通道之间的通路。因此，燃油只有使用低压燃油泵将低压燃油供应通道中的燃油输送到低压燃油喷射机构中去。相应地，这里不需要高压燃油供应通道去供油，而用低压油泵，也就是说提供低压燃油供油通道和高压泵之间通道的低压燃油供应通道和分支通道。能够快速索取燃油，同时燃油能够快速地从低压燃油喷射机构中喷出。因此，配备了将燃油在较高压力下将燃油喷入汽缸的燃油喷射机构和将燃油喷入进气通道或进气端口的内燃机的稳定能够被提高。