JP5956712B2 - V-shaped engine - Google Patents

Description

  The present invention relates to the technology of a V-type engine.

  Conventionally, a so-called V-type engine is known in which a plurality of pistons are arranged in parallel in a first row and a second row, and one crankshaft is rotated by the pistons in each row (see, for example, Patent Document 1). . In the V-shaped engine, the expansion strokes are unevenly spaced by the angle formed by the sliding direction of the first row piston and the sliding direction of the second row piston, that is, the bank angle. In some cases, there was a difference in the exhaust characteristics.

  Here, it is a four-cycle engine that completes each process of an air supply stroke, a compression stroke, an expansion stroke, and an exhaust stroke in one cylinder while the crankshaft makes two revolutions, and is provided with six pistons in each row. A cylinder engine is assumed. Since the V12 cylinder engine has 12 expansion strokes during two revolutions of the crankshaft, it is possible to obtain extremely smooth and stable operation characteristics when the rotation angle of the crankshaft is expanded every 60 degrees. Become. For this reason, in a V12 cylinder engine, setting the bank angle to 60 degrees has been considered important for ensuring engine performance.

  However, when the bank angle is set to 60 degrees, the dimensional problem that the total height becomes large cannot be solved. Therefore, a V12 cylinder engine having a bank angle of 90 degrees is known. Thus, in a V12 cylinder engine with a bank angle of 90 degrees, the rotation angle of the crankshaft is 30 degrees and 90 degrees, and the unequal intervals at which the expansion strokes are alternately performed. In some cases, there were differences in exhaust characteristics.

JP-A-6-193538

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a technique capable of reducing the difference in exhaust characteristics between the first row and the second row in a V-type engine in which the expansion strokes are unevenly spaced. It is said.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

In claim 1, a plurality of pistons slidably provided in the first row, a plurality of pistons slidably provided in the second row, and a crankshaft rotated by sliding of the pistons A fuel injection pump for a first row driven by rotation of the crankshaft, a fuel injection nozzle for pumping fuel from the fuel injection pump for the first row, and a first drive driven by rotation of the crankshaft. A fuel injection pump for two rows, and a fuel injection nozzle to which fuel is pumped from the fuel injection pump for the second row, and a plunger for pumping fuel by sliding on the fuel injection pump; A bank angle which is an angle formed by a sliding direction of the first row of pistons and a sliding direction of the second row of pistons. And 90 degrees, the relationship between the number of cylinders of the piston, the expansion stroke in the cylinder of the first row of the piston becomes after long intervals, the expansion stroke in the cylinder of the second row of the piston is after a short distance, not In a V-shaped engine having an equal interval, the cam shape of the fuel injection pump for the first row and the cam shape of the fuel injection pump for the second row are substantially the same in the shape of the base circle portion and the ramp portion. The cam height at the flank portion continuing from the ramp portion of the fuel injection pump for the first row is configured to be lower than the cam height at the flank portion continuing from the ramp portion of the fuel injection pump for the second row. Reducing the cam speed of the cam shaft of the fuel injection pump for the first row, lowering the fuel injection pressure, and the pressure waveform of the fuel injection pressure in the cylinder of the first row that becomes the expansion stroke after a long interval; Swell after a short interval By approximating the pressure waveform of the fuel injection pressure in the second row of cylinders to be process, it is to substantially equal.

In claim 2, a plurality of pistons slidably provided in the first row, a plurality of pistons slidably provided in the second row, and a crankshaft rotated by sliding of the pistons A fuel injection pump for a first row driven by rotation of the crankshaft, a fuel injection nozzle for pumping fuel from the fuel injection pump for the first row, and a first drive driven by rotation of the crankshaft. A fuel injection pump for two rows, and a fuel injection nozzle to which fuel is pumped from the fuel injection pump for the second row, and a plunger for pumping fuel by sliding on the fuel injection pump; A bank angle which is an angle formed by a sliding direction of the first row of pistons and a sliding direction of the second row of pistons. And 90 degrees, the relationship between the number of cylinders of the piston, the expansion stroke in the cylinder of the first row of the piston becomes after long intervals, the expansion stroke in the cylinder of the second row of the piston is after a short distance, not In a V-shaped engine having an equal interval, the cam shape of the fuel injection pump for the first row and the cam shape of the fuel injection pump for the second row are substantially the same in the shape of the base circle portion and the ramp portion. The cam height at the flank portion continuing from the ramp portion of the fuel injection pump for the second row is configured to be higher than the cam height at the flank portion continuing from the ramp portion of the fuel injection pump for the first row. , Increasing the cam speed of the cam shaft of the second-row fuel injection pump, increasing the fuel injection pressure, and the pressure waveform of the fuel injection pressure in the second-row cylinder that becomes the expansion stroke after a short interval; Bulge after long interval By approximating the pressure waveform of the fuel injection pressure in the first row of cylinders to be process, it is to substantially equal.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, by reducing the fuel injection pressure in the first row cylinder that becomes the expansion stroke after a long interval, the pressure waveform of the fuel injection pressure in the first row cylinder and the second row By approximating the pressure waveform of the fuel injection pressure in the cylinder, the combustion state in the cylinders in the first row and the second row becomes the same, so the difference in exhaust characteristics between the first row and the second row can be reduced. It becomes possible.

  Further, by changing the cam shape of the cam shaft of the fuel injection pump for the first row, the fuel injection pressure can be lowered, and the pressure waveform of the fuel injection pressure in the first row cylinder and the second row cylinder By making it possible to approximate the pressure waveform of the fuel injection pressure in the cylinder, the combustion state in the cylinders in the first row and the second row becomes the same, so the difference in exhaust characteristics between the first row and the second row is reduced. It becomes possible.

  According to the second aspect of the present invention, by increasing the fuel injection pressure in the second row cylinder that becomes the expansion stroke after a short interval, the pressure waveform of the fuel injection pressure in the first row cylinder and the second row cylinder are increased. By approximating the pressure waveform of the fuel injection pressure in the cylinder, the combustion state in the cylinders in the first row and the second row becomes the same, so the difference in exhaust characteristics between the first row and the second row can be reduced. It becomes possible.

  Further, the fuel injection pressure can be increased by changing the cam shape of the cam shaft of the fuel injection pump for the second row, and the pressure waveform of the fuel injection pressure in the first row cylinder and the second row cylinder By making it possible to approximate the pressure waveform of the fuel injection pressure in the cylinder, the combustion state in the cylinders in the first row and the second row becomes the same, so the difference in exhaust characteristics between the first row and the second row is reduced. It becomes possible.

The perspective view which shows the structure of a V-shaped engine. The top view which shows the structure of a V type engine. Sectional drawing which shows the structure of a V-shaped engine. (A) The figure which shows the structure of a fuel injection pump. (B) The figure which shows the fuel pumping and metering by a fuel injection pump. The figure which shows that an expansion stroke becomes an unequal space | interval. (A) The figure which shows the pressure waveform of the fuel injection pressure in the cylinder of the 1st row, and the fuel injection pressure in the cylinder of the 2nd row. (B) The figure which shows the exhaust temperature of the 1st row, and the exhaust temperature of the 2nd row. (A) One figure which shows the cam shape of the cam shaft which comprises a fuel-injection pump. (B) One figure which shows the cam speed of the cam shaft which comprises a fuel-injection pump. (A) One figure which shows the pressure waveform of the fuel injection pressure in the cylinder of the 1st row, and the fuel injection pressure in the cylinder of the 2nd row. (B) One diagram showing the exhaust gas temperature in the first row and the exhaust gas temperature in the second row. (A) The other figure which shows the cam shape of the cam shaft which comprises a fuel injection pump. (B) The other figure which shows the cam speed of the cam shaft which comprises a fuel-injection pump. (A) The other figure which shows the pressure waveform of the fuel injection pressure in the cylinder of the 1st row, and the fuel injection pressure in the cylinder of the 2nd row. (B) The other figure which shows the exhaust temperature of a 1st row, and the exhaust temperature of a 2nd row.

  First, the configuration of the V-type engine 100 according to an embodiment of the present invention will be described. The V-type engine 100 is a V12 cylinder engine provided with six pistons 13 in a first row L and a second row R, respectively. The V-type engine 100 is a diesel engine that burns by injecting fuel into compressed air and obtains rotational power from the expansion energy of the combustion.

  FIG. 1 is a perspective view showing a configuration of a V-type engine 100, and FIG. 2 is a plan view thereof. FIG. 3 is a cross-sectional view showing a configuration of the V-type engine 100. The white arrow in the figure indicates the flow direction of the intake air, and the black arrow in the figure indicates the flow direction of the exhaust.

  The V-shaped engine 100 mainly includes an engine main body 1, two air supply passages 2, two exhaust passages 3, and two fuel injection pumps 4.

  The engine main body 1 is a main structure of the V-shaped engine 100 that obtains rotational power from expansion energy due to combustion. The engine main body 1 is mainly composed of a cylinder block 11, a cylinder head 12, a piston 13, and a crankshaft 14.

  The engine main body 1 includes a cylinder hole 11 c provided in the cylinder block 11, a piston 13 slidably provided in the cylinder hole 11 c, and a cylinder head 12 disposed so as to face the piston 13. And the combustion chamber 15 is comprised by these. The piston 13 is connected to a pin portion of the crankshaft 14 by a connecting rod 16, and the crankshaft 14 is driven to rotate by sliding of the piston 13. The specific operation mode of the engine main body 1 will be described later.

  The air supply passage 2 is a passage that guides intake air sucked from the outside to each combustion chamber 15 provided in the engine main body 1. The air supply passage 2 is mainly composed of an air cleaner 21, a compressor 22, and an air supply manifold 23 along the direction in which the intake air flows.

  The air cleaner 21 filters the intake air with a filter paper or a sponge. The air cleaner 21 prevents foreign matters such as dust from entering the combustion chamber 15 by filtering the intake air.

  The compressor 22 pressurizes the intake air filtered by the air cleaner 21. Specifically, the compressor 22 includes a compressor wheel having a plurality of blades, and pressurizes intake air by rotating the compressor wheel. The compressor wheel of the compressor 22 is connected to a turbine wheel, which will be described later, and is rotationally driven by the turbine wheel.

  The air supply manifold 23 distributes the intake air pressurized by the compressor 22 to each combustion chamber 15. In the V-type engine 100 according to the present embodiment, since six combustion chambers 15 are provided in the first row L and the second row R, one supply manifold 23 is also formed to branch into six passages. Has been. The air supply manifold 23 is fixed to the cylinder head 12 so as to communicate with an intake air passage provided in the cylinder head 12.

  The exhaust passage 3 is a passage that guides the exhaust discharged from each combustion chamber 15 to the exhaust port. The exhaust passage 3 is mainly composed of an exhaust manifold 31 and an exhaust turbine 32 along the direction in which the exhaust flows.

  The exhaust manifold 31 collects exhaust discharged from each combustion chamber 15. In the V-shaped engine 100 according to the present embodiment, since six combustion chambers 15 are provided in the first row L and the second row R, one exhaust manifold 31 also merges six passages into one passage. It is formed as follows. The exhaust manifold 31 is fixed to the cylinder head 12 so as to communicate with an exhaust passage provided in the cylinder head 12.

  The exhaust turbine 32 obtains rotational power using the energy of the exhaust discharged from each combustion chamber 15. Specifically, the exhaust turbine 32 includes a turbine wheel including a plurality of blades, and the turbine wheel is rotated by receiving the exhaust. The turbine wheel of the exhaust turbine 32 is connected to the above-described compressor wheel to rotate the compressor wheel.

  The fuel injection pump 4 is a pumping device that pumps fuel to a fuel injection nozzle 17 attached to the cylinder head 12. The pumping part of the fuel injection pump 4 is mainly composed of a plunger barrel 41, a plunger 42, a delivery valve 43, and a cam shaft 44 (see FIG. 4A). The fuel injection nozzle 17 is fixed to the cylinder head 12 so that the tip portion provided with the injection port 17 h protrudes into the combustion chamber 15.

  In the fuel injection pump 4, a fuel chamber 45 is constituted by a plunger barrel 41, a plunger 42 slidably provided in the plunger barrel 41, and a delivery valve 43 disposed so as to face the plunger 42. Has been. The plunger 42 is urged toward the cam portion of the cam shaft 44 by a spring 46 and is slid by the rotation of the cam shaft 44. A specific operation mode of the fuel injection pump 4 will be described later.

  Here, the operation | movement aspect of the engine main-body part 1 is demonstrated using FIG. Specifically, the operation mode of one cylinder constituted by the piston 13 will be described. The V-type engine 100 is a four-cycle engine that completes each process of an air supply stroke, a compression stroke, an expansion stroke, and an exhaust stroke in one cylinder while the crankshaft 14 rotates twice.

  The air supply process is a process in which intake air is guided into the combustion chamber 15 by opening the air supply valve 12 i provided in the cylinder head 12 and sliding the piston 13 downward.

  The compression step is a step of compressing the air in the combustion chamber 15 by closing the air supply valve 12i and sliding the piston 13 upward. Then, when the fuel is injected from the fuel injection nozzle 17 into the compressed and high temperature and high pressure air, the fuel is dispersed and evaporated in the combustion chamber 15 to start combustion.

  Thereafter, the cylinder shifts to an expansion stroke in which the piston 13 slides downward again. The expansion stroke is a stroke in which the piston 13 is pushed down by an increase in pressure in the combustion chamber 15 due to the combustion of fuel. At this time, rotational power is applied from the piston 13 to the crankshaft 14 via the connecting rod 16.

  And this cylinder transfers to the exhaust stroke which makes the piston 13 slide upward again. The exhaust process is a process of exhausting the exhaust gas in the combustion chamber 15 by opening the exhaust valve 12e and sliding the piston 13 upward.

  In this way, the V-type engine 100 completes the steps of the supply stroke, the compression stroke, the expansion stroke, and the exhaust stroke in one cylinder while the crankshaft 14 rotates twice. The V-type engine 100 can be continuously operated by repeating the above-described strokes in all the cylinders C1, C2, C3.

  Next, the operation mode of the fuel injection pump 4 will be described with reference to FIGS. 4 (A) and 4 (B). In detail, the operation | movement aspect of the one pressure feeding mechanism comprised by the plunger 42 grade | etc., Is demonstrated. However, FIG. 4 used for the following description and description illustrates the structure of a general fuel injection pump, and the detailed structure has different parts.

  As described above, the pumping portion of the fuel injection pump 4 mainly includes the plunger barrel 41, the plunger 42, the delivery valve 43, and the cam shaft 44. The metering unit of the fuel injection pump 4 mainly includes a control sleeve 47, a control rack 48, and an actuator 49.

  A plunger 42 is slidably provided in the plunger barrel 41. A control sleeve 47 that rotates integrally with the plunger 42 is fitted on the middle of the plunger 42 in the axial direction (vertical direction in the drawing). A pinion gear 47 g provided on the outer periphery of the control sleeve 47 is engaged with a rack gear 48 g of the control rack 48. The control rack 48 is connected to an actuator 49 and driven by a control device (not shown).

  As shown in FIG. 4 (B), fuel pumping is started when the plunger 42 sliding in the axial direction (the vertical direction in the figure) closes the port hole 41 p of the plunger barrel 41. More specifically, when the plunger 42 slides to close the port hole 41p of the plunger barrel 41, the pressure of the fuel injected into the fuel chamber 45 increases. Then, when the fuel pressure in the fuel chamber 45 exceeds a predetermined value, the delivery valve 43 is opened and fuel pumping is started.

  Further, as shown in FIG. 4B, fuel metering is possible by adjusting the timing when the plunger 42 closes the port hole 41p and the timing when the plunger 42 communicates again. More specifically, since the notches 42a and 42b are formed in the upper end surface and the middle part of the plunger 42 at predetermined angles, respectively, the timing of communication with the timing of closing the port hole 41p by rotating the plunger 42 And can be adjusted. When the timing for closing the port hole 41p and the timing for communication are adjusted, the valve opening timing and the valve closing timing of the delivery valve 43 are changed to perform fuel metering.

  Thus, the fuel injection pump 4 can slide the plunger 42 by the rotation of the cam shaft 44, and can pump fuel to the fuel injection nozzle 17. Further, in the fuel injection pump 4, the actuator 49 can rotate the plunger 42 via the control rack 48 and the control sleeve 47, so that the fuel pressure-fed to the fuel injection nozzle 17 can be metered.

In the V-type engine 100 configured as described above, the expansion stroke in the first row L cylinders (C1, C3, C5, C7, C9, C11) and the second row R cylinders (C2, C4, C6, The reason why the intervals between the expansion strokes in C8, C10, and C12) are unequal intervals will be described.
The reason why the exhaust characteristics of the first row L and the second row R are different due to the unequal intervals in the expansion stroke will be described.

  As described above, in the V-type engine 100 that is a four-cycle engine and is a V12 cylinder engine, 12 expansion strokes are performed while the crankshaft 14 rotates twice. Therefore, if the rotation angle of the crankshaft 14 is expanded every 60 degrees, extremely smooth and stable operation characteristics can be obtained.

  However, in the V-type engine 100, the angle formed by the sliding direction of the piston 13 in the first row L and the sliding direction of the piston 13 in the second row R, that is, the bank angle Va is 90 degrees ( 3), it is impossible to perform the expansion stroke every 60 degrees of the rotation angle of the crankshaft 14. That is, as shown in FIG. 5, the V-type engine 100 performs the expansion stroke alternately with the rotation angle of the crankshaft 14 being 30 degrees and 90 degrees, and the cylinders (C1, C3, C5, The intervals between the expansion strokes in C7, C9, and C11) and the expansion strokes in the second row R cylinders (C2, C4, C6, C8, C10, and C12) must be unequal. is there.

  As described above, the V-type engine 100 has an unequal interval in which the rotation angle of the crankshaft 14 is alternately 30 degrees and 90 degrees and alternately performs expansion strokes, so that the exhaust characteristics of the first row L and the second row R are different. Had occurred. Specifically, the fuel injection pressure in the cylinders (C1, C3, C5, C7, C9, and C11) in the first row L, which becomes the expansion stroke after a long interval (90 degrees), is expanded after a short interval (30 degrees). Since there is a tendency to become higher than the fuel injection pressure in the second row R cylinders (C2, C4, C6, C8, C10, C12), the exhaust characteristics of the first row L and the second row R are different. It was.

The reason for this is that, as shown in the drawing of FIG. 3, when the crankshaft 14 rotates in the counterclockwise rotation direction D, the cylinders in the first row L (C1, C3, C5, C7, C9, C11) is the compression / expansion stroke 90 degrees after the compression stroke of the cylinders in the second row R (C2, C4, C6, C8, C10, C12), so that the rotational speed of the crankshaft does not drop so much. On the other hand, the cylinders in the second row R (C2, C4, C6, C8, C10, C12) are immediately after the cylinders in the first row L (C1, C3, C5, C7, C9, C11). Since the compression / expansion strokes come at intervals of 30 degrees, the load increases momentarily, causing variations in the rotation angle of the crankshaft, and the cylinders in the second row R (C2, C4, C6, C8, C10) -In the expansion stroke of C12), the rotation speed of the crankshaft is lowered and the cam speed of the camshaft is also lowered. The difference in the cam speed has a correlation with the overflow amount of the fuel from the port hole 41p and the like, and therefore affects the amount of fuel pumped to the fuel injection nozzle 17. In other words, the fuel injection pump 4 for the first row L has a slow cam speed, so that the overflow amount of fuel from the fuel chamber 45 increases and the amount of fuel pumped to the fuel injection nozzle 17 decreases. As a result, the fuel injection pressure in the first row L cylinders that do not take an expansion stroke after a long interval is universally higher than the fuel injection pressure in the second row R cylinders that undergo an expansion stroke after a short interval.

  FIG. 6A shows the fuel injection pressure in the first row L cylinders (C1, C3, C5, C7, C9, C11) and the second row R cylinders (C2, C4, C6, C8, C10, C12). The pressure waveform of the fuel injection pressure in is shown. FIG. 6B shows the exhaust temperature of the first row L and the exhaust temperature of the second row R.

  As shown in FIG. 6A, the fuel injection pressures in the first row L cylinders (C1, C3, C5, C7, C9, C11) indicate that the second row R cylinders (C2, C4, C6, C8, C10, C12). It can be seen that the fuel injection pressure is higher than This is due to the fact that the rotation stroke of the crankshaft 14 is alternately performed at 30 degrees and 90 degrees, so that the cylinders in the first row L (C1, C3, C5, C7,. This shows that the fuel injection pressure in C9 / C11) is higher than the fuel injection pressure in the second row R cylinders (C2, C4, C6, C8, C10, and C12) that are in the expansion stroke after a short interval.

  Further, from FIG. 6B, the exhaust temperature of the first row L is higher than the exhaust temperature of the second row R in the low output region, and the exhaust temperature of the first row L is the first in the high output region. It can be seen that the exhaust temperature of the second row R is lower. This is because the fuel injection pressure in the first row L cylinders (C1, C3, C5, C7, C9, C11) and the fuel injection pressure in the second row R cylinders (C2, C4, C6, C8, C10, C12). This shows that the combustion states in the combustion chambers 15 are different from each other due to the difference in.

  When the combustion states in the combustion chamber 15 are different from each other, it is considered that a difference occurs in the generation amounts of nitrogen oxides (NOx) and particulate matter (PM). More specifically, since nitrogen oxides (NOx) are mainly generated in a high temperature region, they are easily affected by the combustion state, and the first row L cylinders (C1, C3, C5, C7, C9, C11). ) And the second row R cylinders (C2, C4, C6, C8, C10, C12). Further, since the particulate matter (PM) is mainly generated in the low oxygen region, it is easily affected by the combustion state, and the first row L cylinders (C1, C3, C5, C7, C9, C11) and the first This is because there is a difference in the generation amount between the two-row R cylinders (C2, C4, C6, C8, C10, and C12).

  Hereinafter, one means for reducing the difference in the exhaust characteristics between the first row L and the second row R will be described.

  FIG. 7A shows the cam shape of the cam shaft 44 constituting the fuel injection pump 4. The solid line in FIG. 7A shows the cam shape of the fuel injection pump 4 for the first row, and the broken line in FIG. 7A shows the cam shape of the fuel injection pump 4 for the second row. FIG. 7B shows the cam speed of the cam shaft 44 that constitutes the fuel injection pump 4. The solid line in FIG. 7B shows the cam speed of the fuel injection pump 4 for the first row, and the broken line in FIG. 7B shows the cam speed of the fuel injection pump 4 for the second row. The cam speed is synonymous with the sliding speed of the plunger 42 that is slid by the cam portion of the cam shaft 44.

  7A, the cam shape of the fuel injection pump 4 for the first row is substantially the same as the shape of the base circular portion Cb and the ramp portion Cr compared to the cam shape of the fuel injection pump 4 for the second row. It is the same. However, the cam shape of the fuel injection pump 4 for the first row has a lower cam height at the flank portion Cf that continues from the ramp portion Cr.

  From FIG. 7B, the cam speed of the fuel injection pump 4 for the first row is substantially the same in the base circle portion Cb and the ramp portion Cr as compared with the cam speed of the fuel injection pump 4 for the second row. . This is because the mutual cam shapes are substantially the same in the base circle portion Cb and the ramp portion Cr. However, the cam speed of the fuel injection pump 4 for the first row is slower at the flank portion Cf than the cam speed of the fuel injection pump 4 for the second row. This is because the cam height at the flank portion Cf of the fuel injection pump 4 for the first row is low.

  Then, the difference in the cam speed has a correlation with the overflow amount of the fuel from the port hole 41p and the like, and therefore affects the pressure of fuel supplied to the fuel injection nozzle 17. That is, the fuel injection pump 4 for the first row has a slow cam speed, so that the overflow amount of fuel from the fuel chamber 45 increases and the amount of fuel pumped to the fuel injection nozzle 17 decreases.

  With such a configuration, the V-type engine 100 can reduce the fuel injection pressure in the cylinders (C1, C3, C5, C7, C9, and C11) in the first row L that is in the expansion stroke after a long interval. Become. Then, as shown in FIG. 8A, the fuel injection pressure in the first row L cylinders (C1, C3, C5, C7, C9, C11) and the second row R cylinders (C2, C4, C6, C8). It becomes possible to approximate the pressure waveform of the fuel injection pressure in C10 and C12). Further, as shown in FIG. 8B, since the exhaust temperature of the first row L and the exhaust temperature of the second row R are substantially equal, the combustion state in the combustion chamber 15 is the same as each other. It is thought that.

  From the above, since the combustion states in the combustion chamber 15 are the same, there is no difference in the amount of nitrogen oxide (NOx) and particulate matter (PM) produced, and the exhaust characteristics of the first row L and the second row R are the same. The difference can be reduced.

  Hereinafter, another means for reducing the difference in exhaust characteristics between the first row L and the second row R will be described.

  FIG. 9A shows the cam shape of the cam shaft 44 constituting the fuel injection pump 4. The solid line in FIG. 9A shows the cam shape of the fuel injection pump 4 for the first row, and the broken line in FIG. 9A shows the cam shape of the fuel injection pump 4 for the second row. FIG. 9B shows the cam speed of the cam shaft 44 that constitutes the fuel injection pump 4. The solid line in FIG. 9B indicates the cam speed of the fuel injection pump 4 for the first row, and the broken line in FIG. 9B indicates the cam speed of the fuel injection pump 4 for the second row. The cam speed is synonymous with the sliding speed of the plunger 42 that is slid by the cam portion of the cam shaft 44.

  9A, the cam shape of the fuel injection pump 4 for the second row is substantially the same as the shape of the base circular portion Cb and the ramp portion Cr compared to the cam shape of the fuel injection pump 4 for the first row. It is the same. However, the cam shape of the fuel injection pump 4 for the second row is such that the cam height is high at the flank portion Cf continuous from the ramp portion Cr.

  From FIG. 9B, the cam speed of the fuel injection pump 4 for the second row is substantially the same in the base circle portion Cb and the ramp portion Cr as compared with the cam speed of the fuel injection pump 4 for the first row. . This is because the mutual cam shapes are substantially the same in the base circle portion Cb and the ramp portion Cr. However, the cam speed of the fuel injection pump 4 for the second row is higher at the flank portion Cf than the cam speed of the fuel injection pump 4 for the first row. This is because the cam height in the flank portion Cf of the fuel injection pump 4 for the first row is high.

  Then, the difference in the cam speed has a correlation with the overflow amount of the fuel from the port hole 41p and the like, and therefore affects the pressure of fuel supplied to the fuel injection nozzle 17. That is, the fuel injection pump 4 for the second row has a high cam speed, so that the overflow amount of fuel from the fuel chamber 45 decreases, and the amount of fuel pumped to the fuel injection nozzle 17 increases.

  With this configuration, the V-type engine 100 can increase the fuel injection pressure in the second row R cylinders (C2, C4, C6, C8, C10, and C12) that are in the expansion stroke after a short interval. Become. 10A, the fuel injection pressure in the first row L cylinders (C1, C3, C5, C7, C9, and C11) and the second row R cylinders (C2, C4, C6, and C8). It becomes possible to approximate the pressure waveform of the fuel injection pressure in C10 and C12). As shown in FIG. 10 (B), the exhaust temperature in the first row L and the exhaust temperature in the second row R are substantially equal, so that the combustion states in the combustion chamber 15 are the same. It is thought that.

  As described above, since the combustion states in the combustion chamber 15 are similar to each other, there is no difference in the amount of nitrogen oxide (NOx) and particulate matter (PM) generated, and the exhaust characteristics of the first row L and the second row R are the same. The difference can be reduced.

DESCRIPTION OF SYMBOLS 100 V type engine 1 Engine main part 11 Cylinder block 12 Cylinder head 13 Piston 14 Crankshaft 15 Combustion chamber 16 Connecting rod 17 Fuel injection nozzle 2 Air supply passage 21 Air cleaner 22 Compressor 23 Air supply manifold 3 Exhaust passage 31 Exhaust manifold 32 Exhaust turbine 4 Fuel Injection Pump 41 Plunger Barrel 42 Plunger 43 Delivery Valve 44 Cam Shaft 45 Fuel Chamber L First Row R Second Row Va Bank Angle

Claims (2)

A plurality of pistons slidably provided in the first row;
A plurality of pistons slidably provided in the second row;
A crankshaft rotated by sliding of the piston;
A fuel injection pump for the first row driven by rotation of the crankshaft;
A fuel injection nozzle to which fuel is pumped from the fuel injection pump for the first row;
A second-row fuel injection pump driven by rotation of the crankshaft;
A fuel injection nozzle that pumps fuel from the fuel injection pump for the second row,
The fuel injection pump includes a plunger that slides the fuel by sliding, and a cam shaft that is driven by the crankshaft to slide the plunger.
The bank angle, which is an angle formed by the sliding direction of the first row of pistons and the sliding direction of the second row of pistons, is 90 degrees,
From the relationship with the number of piston cylinders, the expansion strokes in the cylinders of the first row of pistons are after a long interval, and the expansion strokes in the cylinders of the second row of pistons are after a short interval , resulting in unequal intervals. In V type engine,
The cam shape of the fuel injection pump for the first row and the cam shape of the fuel injection pump for the second row are substantially the same in the shape of the base circle portion and the ramp portion,
The cam height at the flank portion continuous from the ramp portion of the fuel injection pump for the first row is configured to be lower than the cam height at the flank portion continuous from the ramp portion of the fuel injection pump for the second row,
Decreasing the cam speed of the cam shaft of the fuel injection pump for the first row, lowering the fuel injection pressure,
By approximating the pressure waveform of the fuel injection pressure in the cylinder of the first row that becomes the expansion stroke after a long interval and the pressure waveform of the fuel injection pressure in the cylinder of the second row that becomes the expansion process after a short interval, they are approximately the same. A V-shaped engine characterized by A plurality of pistons slidably provided in the first row;
A plurality of pistons slidably provided in the second row;
A crankshaft rotated by sliding of the piston;
A fuel injection pump for the first row driven by rotation of the crankshaft;
A fuel injection nozzle to which fuel is pumped from the fuel injection pump for the first row;
A second-row fuel injection pump driven by rotation of the crankshaft;
A fuel injection nozzle that pumps fuel from the fuel injection pump for the second row,
The fuel injection pump includes a plunger that slides the fuel by sliding, and a cam shaft that is driven by the crankshaft to slide the plunger.
The bank angle, which is an angle formed by the sliding direction of the first row of pistons and the sliding direction of the second row of pistons, is 90 degrees,
From the relationship with the number of piston cylinders, the expansion strokes in the cylinders of the first row of pistons are after a long interval, and the expansion strokes in the cylinders of the second row of pistons are after a short interval , resulting in unequal intervals. In V type engine,
The cam shape of the fuel injection pump for the first row and the cam shape of the fuel injection pump for the second row are substantially the same in the shape of the base circle portion and the ramp portion,
The cam height in the flank portion continuous from the ramp portion of the fuel injection pump for the second row is configured to be higher than the cam height in the flank portion continuous from the ramp portion of the fuel injection pump for the first row,
Increase the cam speed of the camshaft of the fuel injection pump for the second row and increase the fuel injection pressure,
By approximating the pressure waveform of the fuel injection pressure in the cylinder of the second row that becomes the expansion stroke after a short interval and the pressure waveform of the fuel injection pressure in the cylinder of the first row that becomes the expansion step after a long interval, A V-shaped engine characterized by

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