The disclosure is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-087625, filed on May 30, 2022, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a fuel pressurization device.
Japanese Patent Publication No. 2019-52593 discloses an engine mounted on a brush cutter. Fuel for starting an engine is sent to a carburetor by a priming pump, and the fuel is stored in the carburetor. The fuel stored in the carburetor is sent into the engine with a negative pressure of the engine.
Disclosed herein is an example fuel pressurization device. The fuel pressurization device is provided in an engine assembly including a pump, a valve, and an engine and pressure-feeds starting fuel supplied from the pump to the engine via the valve. The fuel pressurization device has a fuel chamber forming portion including a fuel chamber to which the fuel is supplied from the pump and whose internal volume is variable, and a spring configured to bias the fuel chamber forming portion such that the volume of the fuel chamber decreases.
In the fuel pressurization device, the fuel chamber forming portion is biased by the spring, and thus the fuel supplied by the pump is pressurized in the fuel chamber. For example, the valve provided in the engine assembly is closed and the fuel is being pressurized when the fuel is being supplied into the fuel chamber by the pump. In this state, when the valve provided in the engine assembly is opened to start the engine, the pressurized fuel is supplied to the engine. In this way, the fuel pressurization device may pressure-feed the fuel for starting to the engine to enhance the startability of the engine.
In some examples, the fuel chamber forming portion includes an elastically deformable elastic body in at least a part thereof, the volume of the fuel chamber changes as the elastic body deforms, and the spring (30) biases the elastic body. Accordingly, the fuel pressurization device may be able to readily change the volume of the fuel chamber using the elastic body.
In some examples, the fuel pressurization device may include an overflow channel that is connected to a discharge channel, through which the fuel sent out from the fuel chamber passes, to branch off from the discharge channel And the fuel pressurization device may include an overflow valve configured to switch between whether or not to circulate the fuel in the overflow channel Additionally, the fuel pressurization device may be able to discharge surplus fuel supplied into the fuel chamber by the pump via the overflow valve and the overflow channel.
In some examples, the overflow valve includes a valve body and a valve body spring that biases the valve body such that the flow of the fuel is cut off in the overflow channel. The fuel pressurization device adjusts a balance between the biasing forces of the spring that biases the fuel chamber forming portion and the valve body spring of the overflow valve, and thus it sets the volume of the fuel chamber. In some examples, the fuel pressurization device sets the volume of the fuel chamber by changing the balance between the biasing forces of the springs without changing the fuel chamber forming portion. The fuel pressurization device may be configured for use in these engines even in a case where the amount of the starting fuel to be pressure-fed varies depending on the type of engine or the like.
Additionally, an example fuel pressurization device for use with an engine assembly is disclosed herein. The engine assembly includes a pump, a valve, and an engine. The fuel pressurization includes a fuel chamber forming portion including a fuel chamber to which the fuel is supplied from the pump and whose internal volume is variable, and a spring configured to bias the fuel chamber forming portion such that the volume of the fuel chamber decreases. The fuel pressurization device is configured to pressure-feed the fuel from the fuel chamber to the engine via the valve of the engine assembly when starting the engine.
Additionally, an example fuel pressurization device for use with an engine assembly is disclosed herein. The fuel pressurization device configured to supply fuel to an engine, the fuel pressurization device has a main body including a discharge port, a fuel chamber located inside the main body and fluidly coupled with the discharge port, and a spring. The fuel chamber is configured to be variable in volume. The spring is configured to bias the fuel chamber so as to reduce the volume and apply pressure to the fuel in the fuel chamber when starting the engine.
Additionally, an example engine assembly is disclosed herein. The engine assembly includes an engine, and a fuel pressurization device configured to pressure-feed fuel to the engine. The fuel pressurization device includes a fuel chamber fluidly coupled with the engine and configured to be variable in volume, and a spring configured to bias the fuel chamber so as to reduce the volume and apply pressure to the fuel in the fuel chamber when starting the engine.
In the following description, with reference to the drawings, the same reference numbers are assigned to the same components or to similar components having the same function, and overlapping description is omitted.
As shown in
When the engine 2 is started, the fuel pressurization device 1 pressure-feeds starting fuel supplied from the priming pump 3 to the engine 2 (for example, the inside of a crankcase or the inside of a combustion chamber) via the electromagnetic valve 4 (e.g., fuel valve). The following description focuses on a configuration in which the fuel pressurization device 1 pressure-feeds the starting fuel.
The priming pump 3 is operated by the user of the engine assembly 100 to supply the fuel from a fuel tank 5 to the fuel pressurization device 1. Here, the priming pump 3 takes in the fuel from the fuel tank 5 via a pipe L4 and supplies the fuel to the fuel pressurization device 1 via a pipe L3.
The electromagnetic valve 4 switches between whether or not to supply the starting fuel from the fuel pressurization device 1 to the engine 2. Here, the electromagnetic valve 4 is provided in a pipe L1 (e.g., discharge pipe) for supplying the starting fuel from the fuel pressurization device 1 to the engine 2. The electromagnetic valve 4 is switched between an open state in which the fuel can circulate through the pipe L1 and a closed state in which the flow of the fuel through the pipe L1 is cut off. The electromagnetic valve 4 is switched from the closed state to the open state when the engine 2 is started. For example, the electromagnetic valve 4 may be switched from the closed state to the open state in conjunction with the operation of a recoil starter that is operated when the engine 2 is started.
As shown in
As shown in
The first main body portion 11 is provided with a hole 11a penetrating in the overlapping direction of the first main body portion 11 and the second main body portion 12. The second main body portion 12 is provided with a recess 12a in a portion facing the hole 11a of the first main body portion 11.
The elastic body 20 is disposed to cover the recess 12a of the second main body portion 12. The elastic body 20 is fixed by the edge of the elastic body 20 together with the gasket G being sandwiched between the first main body portion 11 and the second main body portion 12. The elastic body 20 is an elastically deformable member. For example, the elastic body 20 is made of rubber or the like. The elastic body 20 is sheet-like.
Here, the fuel is supplied from the priming pump 3 to a space between the second main body portion 12 and the elastic body 20. The space between the wall surface of the recess 12a of the second main body portion 12 and the elastic body 20 serves as a fuel chamber R to which the fuel is supplied. For example, the fuel chamber R includes the elastic body 20 and the recess 12a of the second main body portion 12. Moreover, as described above, the elastic body 20 is elastically deformable. Therefore, the volume of the fuel chamber R changes as the elastic body 20 deforms (see a difference between the fuel chambers R in
As shown in
Further, as shown in
As shown in
The overflow channel L13 connects the discharge channel L12 and the overflow outlet port S3 to each other. That is, the overflow channel L13 has one end portion connected to the discharge channel L12 to branch off from the discharge passage L12 and the other end portion connected to the overflow outlet port S3. The overflow channel L13 is formed by a hole provided in the first main body portion 11 and a hole provided in the second main body portion 12.
The overflow valve 40 is provided in the overflow channel L13 and switches between whether or not to circulate the fuel in the overflow channel L13. The overflow valve 40 is switched between an open state in which the fuel can circulate through the overflow channel L13 and a closed state in which the flow of the fuel through the overflow channel L13 is cut off, depending on the pressure of the fuel in the fuel chamber R.
The overflow channel L13 includes a small-diameter flow channel portion Ll3a connected to the discharge channel L12 and a large-diameter flow channel portion Ll3b connected to the small-diameter flow channel portion L13a. The large-diameter flow channel portion L13b has a larger flow channel cross-sectional area than the small-diameter flow channel portion L13a. In addition, the small-diameter flow channel portion L13a is positioned closer to the discharge channel L12 than the large-diameter flow channel portion L13b. The small-diameter flow channel portion L13a is provided in the first main body portion 11, and the large-diameter flow channel portion L13b is provided in the second main body portion 12. The overflow valve 40 opens and closes an opening portion Ll3c of the small-diameter flow channel portion Ll3a at a connection portion between the small-diameter flow channel portion L13a and the large-diameter flow channel portion L13b to switch between whether or not to circulate the fuel in the overflow channel L13.
The small-diameter flow channel portion L13a is an example of a first part of the overflow channel L13. The large-diameter flow channel portion L13b is an example of a second part of the overflow channel L13. The small-diameter flow channel portion L13a is fluidly coupled with the first part L12a of the discharge channel L12. The large-diameter flow channel portion L13b is fluidly coupled with the small-diameter flow channel portion L13a and the overflow outlet port S3.
The overflow valve 40 controls a flow of the fuel into the overflow channel L13 based on a pressure in the discharge channel L12. The overflow valve 40 includes a valve body 41 and a spring (a valve body spring) 42. The valve body 41 is provided in the large-diameter flow channel portion L13b and opens and closes the opening portion L13c of the small-diameter flow channel portion L13a. The spring 42 is a compression spring. The spring 42 biases the valve body 41 to cut off the flow of the fuel in the overflow channel L13. Here, the spring 42 biases the valve body 41 such that the opening portion L13c of the small-diameter flow channel portion L13a is cut off by the valve body 41. One end portion of the spring 42 is in contact with the valve body 41, and the other end portion thereof is in contact with a spring retainer 13 provided in the second main body portion 12. The spring retainer 13 is attached to the second main body portion 12 with an O-ring interposed therebetween. As an example, a male screw portion 13a is provided on the outer peripheral surface of the spring retainer 13. A female screw portion 12b is provided on the inner peripheral surface of a hole portion in the second main body portion 12 into which the spring retainer 13 is fitted. The spring retainer 13 is attached to the second main body portion 12 by the male screw portion 13a engaging with the female screw portion 12b of the second main body portion 12.
In the overflow valve 40, the spring 42 is compressed when the pressure of the fuel in the fuel chamber R becomes a predetermined pressure or more, and the valve body 41 separates from the opening portion L13c of the small-diameter flow channel portion L13a. As a result, the opening portion L13c is opened, and the fuel can circulate through the overflow channel L13. In this case, the fuel in the fuel chamber R (surplus fuel) is returned from the fuel pressurization device 1 to the fuel tank 5 via the pipe L2 by being able to circulate through the overflow channel L13.
Next, the operation of the fuel pressurization device 1 for pressure-feeding the starting fuel to the engine 2 when starting the engine 2 will be described. It is assumed that the electromagnetic valve 4 is closed before the engine 2 is started. First, the user of the engine assembly 100 operates (presses) the priming pump 3 to start the engine 2. As a result, the fuel in the fuel tank 5 is sent to the intake port S1 of the fuel pressurization device 1 via the pipe L4, the priming pump 3, and the pipe L3, and the fuel is sent from the intake port S1 into the fuel chamber R via the inflow channel L11.
When the user further operates the priming pump 3 to send the fuel to the fuel pressurization device 1, as shown in
When the user further operates the priming pump 3 to send the fuel to the fuel pressurization device 1, as shown in
After the fuel is stored in the fuel chamber R, the user starts the engine 2 by operating a recoil starter, for example. The electromagnetic valve 4 is changed from the closed state to the open state in conjunction with the operation of starting the engine 2. As a result, as shown in FIG. 8, the starting fuel in the fuel chamber R pressurized by the spring 30 is vigorously sent (pressure-fed) to the engine 2 at once via the discharge channel L12 and the pipe L1. In this way, since the starting fuel is supplied at once when the engine 2 is started, startability of the engine 2 is improved.
As described above, in the fuel pressurization device 1, the elastic body 20 is biased by the spring 30, and thus the fuel supplied by the priming pump 3 is pressurized in the fuel chamber R. In pressuring the fuel, when the fuel is being supplied into the fuel chamber R by the priming pump 3, the electromagnetic valve 4 provided in the engine assembly 100 is closed. In this state, when the electromagnetic valve 4 provided in the engine assembly 100 is opened to start the engine 2, the pressurized fuel is vigorously supplied to the engine 2 at once. In this way, the fuel pressurization device 1 can pressure-feed the fuel for starting to the engine 2 to enhance the startability of the engine 2.
The fuel chamber R includes the elastically deformable elastic body 20 in at least a part thereof. In this case, the fuel pressurization device 1 can readily change the volume of the fuel chamber R using the elastic body 20.
The fuel pressurization device 1 includes the overflow channel L13 that branches off from the discharge channel L12 and the overflow valve 40 that switches between whether or not to circulate the fuel in the overflow channel L13. In this case, the fuel pressurization device 1 can discharge the surplus fuel supplied into the fuel chamber R by the priming pump 3 via the overflow valve 40 and the overflow channel L13.
The overflow valve 40 includes the valve body 41 and the spring 42 that biases the valve body 41. In this case, the fuel pressurization device 1 adjusts a balance between the biasing forces of the spring 30 that biases the elastic body 20 and the spring 42 of the overflow valve 40, and thus it sets the volume of the fuel chamber R. In some examples, the fuel pressurization device 1 sets the volume of the fuel chamber R to a desired value by changing the balance between the biasing forces of the springs 30 and 42 without changing the second main body portion 12 (the recess 12a) and the elastic body 20. As a result, the fuel pressurization device 1 can be configured for use with these engines 2 even in a case where the amount of the starting fuel to be pressure-fed varies depending on the type of engine 2 or the like.
It is to be understood that not all aspects, advantages and features described herein may necessarily be achieved by, or included in, any one particular example. Indeed, having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail.
For example, the pump for sending the fuel to the fuel chamber R is not limited to the priming pump 3. Other types of pumps may be used for sending the fuel to the fuel chamber R of the fuel pressurization device 1. Further, in addition to the electromagnetic valve 4 described herein, other types of valves providing similar functionality may be used.
Number | Date | Country | Kind |
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2022-087625 | May 2022 | JP | national |