JP2014025362A - Engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine that allows a cam angle to be accurately measured and is entirely reduced in size.SOLUTION: An engine comprises: a gear case flange 5; a gear case 7 covering an outside of the gear case flange 5; a supply pump 41 fixed to the gear case flange 5; a pump gear 41G fixed to a driving shaft 41S of the supply pump 41; and a cam gear 18G that engages with the pump gear 41G and is fixed to a camshaft 18. The pump gear 41G and the cam gear 18G are constituted of helical gears. A pulser 70 for detecting a cam angle is provided outside the pump gear 41G, and a cam angle sensor 71 is adjacently disposed at an outer peripheral side of the pulser 70.

Description

  The present invention relates to engine technology.

Conventionally, an engine that injects fuel into a combustion chamber provided on an upper surface of a piston and burns the fuel in the combustion chamber is known. In the engine, the cylinder is determined by a combination of a crank angle signal output from the crank angle sensor according to the rotation of the crankshaft and a cam angle signal output from the cam angle sensor according to the rotation of the camshaft. Based on the cylinder discrimination result, fuel injection and ignition are performed for each cylinder. The engine is driven by such fuel injection and ignition for each cylinder (see, for example, Patent Document 1).
In a conventional engine, a cam gear fixed to a cam shaft is disposed on the front side of the engine. In addition, a cam angle sensor as a rotation angle detecting means is disposed close to the outer peripheral side of the camshaft pulsar attached to the cam gear. The cam angle sensor outputs a cam angle signal when the detected portion of the camshaft pulser passes near the cam angle sensor as the camshaft rotates.

JP 2011-231734 A

However, when a camshaft pulser is provided on the camshaft and the cam angle sensor is disposed close to the camshaft pulser, for example, if the cam gear is a helical gear, the cam gear is easily pushed forward, and the cam angle sensor and cam cam An error was likely to occur in the distance to the shaft pulser. For this reason, the cam angle may not be measured accurately.
Further, depending on the position where the cam angle sensor is disposed, only the cam angle sensor may protrude forward from the other engine parts, and the size of the entire engine may increase.

  In view of the above problems, an object of the present invention is to provide an engine capable of accurately measuring a cam angle and reducing the size of the entire engine.

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

  That is, in claim 1, a gear case flange, a gear case covering the outside of the gear case flange, a supply pump fixed to the gear case flange, a pump gear fixed to a drive shaft of the supply pump, and the pump gear mesh with each other. And a cam gear fixed to the camshaft, wherein the pump gear and the cam gear are composed of helical gears, and a pulsar for detecting a cam angle is provided outside the pump gear, and the pulsar rotates on the outer peripheral side of the pulsar. The corner detection means is arranged in proximity.

  According to a second aspect of the present invention, the rotation angle detecting means is supported by the gear case.

  According to a third aspect of the present invention, the pump gear is disposed above the cam gear and at a position inclined in the left-right direction.

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

  According to the first aspect of the present invention, the force is applied to the pump gear that moves backward, so that the pulser does not move forward, and an error is prevented from occurring in the distance between the rotation angle detecting means and the pulser. The cam angle can be measured accurately.

  According to the second aspect of the present invention, the size of the entire engine can be reduced by partially storing the rotation angle detection means in the gear case.

  According to the third aspect, compared with the case where the pump gear is arranged immediately above the cam gear, the arrangement in the height direction can be made compact by inclining left and right sides, and the overall size of the engine can be reduced. Can do.

The front view which shows the structure of a diesel engine. The right view which shows the structure of a diesel engine. The schematic diagram which shows the operation | movement aspect of a diesel engine. The figure which shows the gear train which transmits the rotational power of a crankshaft. (5A) The figure which expanded the area | region R shown in FIG. (5B) The figure seen from the direction of arrow T shown in FIG. The enlarged view which shows a gear train. Side surface sectional drawing which shows a pulsar, a cam angle sensor, and a gear case.

  First, a diesel engine 100 as an embodiment of the engine will be briefly described.

  FIG. 1 is a front view showing the configuration of the diesel engine 100, and FIG. 2 is a right side view thereof. FIG. 3 is a schematic diagram showing an operation mode of the diesel engine 100. The arrow Fa in the figure indicates the flow direction of the sucked air, and the arrow Fe in the figure indicates the flow direction of the exhaust gas. An arrow S in the figure indicates the sliding direction of the piston 13, and an arrow R in the figure indicates the rotational direction of the crankshaft 14.

  The diesel engine 100 mainly includes an engine main body 1, an intake path 2, an exhaust path 3, and a common rail system 4.

  The engine main body 1 generates rotational power using expansion energy generated by fuel 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 11c provided in a cylinder block 11, a piston 13 slidably provided in the cylinder 11c, a cylinder head 12 disposed so as to face the piston 13, The working chamber W is configured as described above. In other words, the working chamber W means an internal space of the cylinder 11c whose volume is changed by the sliding movement of the piston 13. The piston 13 is connected to a pin portion of the crankshaft 14 by a connecting rod 15, and the crankshaft 14 is rotated by sliding of the piston 13. The specific operation mode of the engine main body 1 will be described later.

  The intake path 2 guides air sucked from outside into the cylinder 11c. That is, the intake path 2 guides air sucked from the outside to the working chamber W. The intake path 2 is mainly composed of an air cleaner (not shown) and an intake manifold 22 along the direction in which air flows.

  The air cleaner filters air taken in by filter paper or sponge. The air cleaner prevents foreign matters such as dust from entering the working chamber W by filtering the air.

  The intake manifold 22 distributes the air filtered by the air cleaner 21 to each working chamber W. Since this diesel engine 100 is a multi-cylinder engine provided with a plurality of working chambers W, the intake manifold 22 is formed so as to cover the inlet hole of the intake port 12Ip provided for each working chamber W. Yes. In the diesel engine 100, since the inlet hole of the intake port 12Ip is provided on the upper surface of the cylinder head 12, the intake manifold 22 is also attached to the upper surface of the cylinder head 12.

  The exhaust path 3 guides the exhaust discharged from the cylinder 11c to the exhaust port. That is, the exhaust path 3 guides the exhaust discharged from each working chamber W to the exhaust port. The exhaust path 3 is mainly composed of an exhaust manifold 31 and an exhaust purification device 32 along the direction in which the exhaust flows.

  The exhaust manifold 31 collects the exhaust discharged from each working chamber W. Since the diesel engine 100 is a multi-cylinder engine provided with a plurality of working chambers W, the exhaust manifold 31 is formed so as to communicate with an outlet hole of an exhaust port 12Ep provided for each working chamber W. ing. In the diesel engine 100, since the outlet hole of the exhaust port 12 </ b> Ep is provided on the side surface of the cylinder head 12, the exhaust manifold 31 is also attached to the side surface of the cylinder head 12.

  The exhaust purification device 32 removes environmental load substances contained in the exhaust. The exhaust purification device 32 contains an oxidation catalyst carrier (Diesel Oxidation Catalyst: hereinafter referred to as “DOC”). DOC oxidizes and detoxifies CO (carbon monoxide) and HC (hydrocarbon) contained in exhaust gas, and oxidizes and removes SOF (organic soluble component) that is a particulate material.

  The common rail system 4 is a fuel injection device that can freely set an injection pattern. The common rail system 4 mainly includes a supply pump 41, a rail 42, and an injector 43.

  The supply pump 41 pressure-feeds the fuel supplied from the fuel tank to the rail 42. Supply pump 41 is driven by the rotational power of crankshaft 14 transmitted through a plurality of gears. The supply pump 41 includes a plunger that slides by the rotation of the drive shaft 41 </ b> S, and sends fuel pressurized by the plunger to the rail 42.

  The rail 42 stores the fuel pumped from the supply pump 41 at a high pressure. The rail 42 is a metal tube formed in a substantially cylindrical shape. The rail 42 includes a limiter valve and is designed so that the fuel pressure does not exceed a predetermined value. In addition, a plurality of pipes are attached to the rail 42 and fuel can be guided to the injectors 43.

  The injector 43 appropriately injects fuel supplied from the rail 42. The injector 43 is attached to the cylinder head 12 so that a tip end portion having an injection port protrudes into the working chamber W. The injector 43 includes an armature that is driven by, for example, a piezo element or a solenoid, and various injection patterns can be realized by adjusting the driving time and period.

  In the diesel engine 100, the fuel pumping timing of the supply pump 41 and the fuel injection timing of the injector 43 are synchronized in order to reduce the fuel pressure fluctuation in the rail 42. Therefore, the meshing position of the pump gear 41G and the cam gear 18G described later is important. A structure capable of confirming the meshing position of the pump gear 41G and the cam gear 18G will be described later.

  Next, the operation mode of the diesel engine 100 will be briefly described with reference to FIG. The diesel engine 100 is a four-cycle engine that completes the intake stroke, compression stroke, expansion stroke, and exhaust stroke processes while the crankshaft 14 rotates twice.

  The intake process is a process in which the intake valve 12Iv is opened and the piston 13 is slid downward to suck air into the working chamber W. The intake valve 12Iv is opened when the camshaft 18 pushes up the push rod and the push rod pushes the valve arm (see FIG. 4). The camshaft 18 is driven by the rotational power of the crankshaft 14 transmitted through a plurality of gears.

  The compression process is a process in which the air in the working chamber W is compressed by closing the intake valve 12Iv and sliding the piston 13 upward. The intake valve 12Iv is closed by the biasing force of the spring. The valve arm is pushed by the intake valve 12Iv, and the push rod is pushed down by the valve arm.

  Thereafter, fuel is injected from the injector 43 into the air that has been compressed to a high temperature and high pressure. Then, the fuel is dispersed and evaporated in the combustion chamber C provided on the upper surface of the piston 13 and mixed with air to start combustion. Thus, the diesel engine 100 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 the expansion energy due to the combustion of the fuel. The flame formed in the combustion chamber C and the working chamber W expands air and pushes down the piston 13. In the expansion stroke, rotational torque is applied from the piston 13 to the crankshaft 14 via the connecting rod 15. At this time, since the kinetic energy is stored by the flywheel 16 attached to the crankshaft 14, the crankshaft 14 continues to rotate (see FIG. 2). Thus, the diesel engine 100 slides the piston 13 upward again to shift to the exhaust stroke.

  The exhaust process is a process of opening the exhaust valve 12Ev and sliding the piston 13 upward to push out the burned gas in the working chamber W as exhaust. The exhaust valve 12Ev is opened when the camshaft 18 pushes up the push rod and the push rod pushes the valve arm (see FIG. 4). The camshaft 18 is driven by the rotational power of the crankshaft 14 transmitted through a plurality of gears.

  Thus, the diesel engine 100 completes the steps of the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke while the crankshaft 14 rotates twice. The diesel engine 100 can be continuously operated by repeating the above steps in all the working chambers W.

  Next, a structure for transmitting the rotational power of the crankshaft 14 to the camshaft 18 and the supply pump 41 will be described.

  FIG. 4 is a diagram showing a gear train that transmits the rotational power of the crankshaft 14. The arrows shown in the figure indicate the rotation direction of each gear.

  As described above, rotational torque is applied to the crankshaft 14 by the expansion energy resulting from the combustion of fuel. Since the crank gear 14G is fixed to the crankshaft 14, it rotates together with the crankshaft 14.

  The idle gear 17G is rotatably supported while being engaged with the crank gear 14G. The idle gear 17G rotates following the rotation of the crank gear 14G. The idle shaft 17 that supports the idle gear 17G is fixed to the cylinder block 11. In the diesel engine 100, the idle gear 17G is disposed on the right side (the left side in FIG. 4) of the crank gear 14G.

  The cam gear 18G is rotatably supported while being engaged with the idle gear 17G. The cam gear 18G rotates following the rotation of the idle gear 17G. Since the cam gear 18G is fixed to the camshaft 18, the camshaft 18 is rotated. That is, the rotational power of the crankshaft 14 is transmitted to the camshaft 18 via the crank gear 14G and the idle gear 17G. In the diesel engine 100, the cam gear 18G is disposed above the idle gear 17G. Accordingly, the camshaft 18 is disposed on the upper right side of the crankshaft 14 (upper left side in FIG. 4).

The pump gear 41G is rotatably supported while being engaged with the cam gear 18G. The pump gear 41G is driven to rotate as the cam gear 18G rotates.
Further, the pump gear 41G and the cam gear 18G are constituted by helical gears. With this configuration, since the tooth contact is dispersed, the sound is quiet and torque fluctuation is small. In addition, when torque is applied to the pump gear 41G and the cam gear 18G, the pump gear 41G releases the force to the rear of the engine and the cam gear 18G releases the force to the front of the engine so as to cancel out the thrust. .

  Since the pump gear 41G is fixed to the drive shaft 41S of the supply pump 41, the supply pump 41 is driven. That is, the rotational power of the crankshaft 14 is transmitted to the supply pump 41 via the crank gear 14G, the idle gear 17G, and the cam gear 18G. In the diesel engine 100, the pump gear 41G is disposed on the upper right side of the cam gear 18G (upper left side in FIG. 4). Accordingly, the supply pump 41 is disposed on the upper right side of the crankshaft 14 (upper left side in FIG. 4).

  As described above, in the diesel engine 100, the gears are arranged in series from the crank gear 14G toward the upper right side (upward left side in FIG. 4). The cam gear 18G and the pump gear 41G also constitute part of this gear train. By doing so, the supply pump 41 is inevitably disposed in the vicinity of the intake valve 12Iv and the exhaust valve 12Ev that are movable by the camshaft 18, in addition to the camshaft 18.

  With this configuration, the diesel engine 100 can work from a certain direction without moving when the maintenance of the intake valve 12Iv, the exhaust valve 12Ev, the supply pump 41, and the like is performed, thereby improving maintainability. It becomes possible. Specifically, it is possible to work from the direction of the arrow X shown in FIG. 1 and to improve maintainability.

  Further, as described above, in the diesel engine 100, the gears are arranged in series from the crank gear 14G toward the upper right side (upward left side in FIG. 4). That is, the diesel engine 100 has a gear train in which each gear is arranged in the vertical direction. Thereby, the full width of the diesel engine 100 can be reduced.

  Next, a structure for attaching the supply pump 41 will be described.

  FIG. 5A is an enlarged view of the region R shown in FIG. 5B is a view as seen from the direction of the arrow T shown in FIG.

  The gear case flange 5 is a member for supporting the supply pump 41 and an oil pump (not shown). The gear case flange 5 is fixed to the cylinder block 11 with a plurality of bolts.

  The spacer 6 is a member for attaching the supply pump 41 to the gear case flange 5. The spacer 6 is fixed to the gear case flange 5 by a plurality of bolts. The spacer 6 is fixed not to the front side of the gear case flange 5 on which each gear is arranged but to the back side. More specifically, the spacer 6 is fixed to the back side of the gear case flange 5 and to the right side of the engine main body 1 (see FIG. 2).

  The gear case 7 is a member for protecting the pump gear 41G and other gears. The gear case 7 is formed so as to cover all the above-described gear train. That is, the gear case 7 can accommodate the pump gear 41G and other gears. The gear case 7 is fixed to the cylinder block 11 and the spacer 6 together with the gear case flange 5 by a plurality of bolts.

  The supply pump 41 is fixed to the spacer 6 with a plurality of bolts. Since the spacer 6 is fixed to the right side of the engine main body 1 on the back surface side of the gear case flange 5, the supply pump 41 is also arranged at the same position. That is, the supply pump 41 is fixed to the right side of the engine main body 1 via the spacer 6 on the back side of the gear case flange 5 (see FIG. 2).

Next, a pulsar provided in the pump gear 41G and a cam angle sensor as a rotation angle detecting means will be described with reference to FIGS.
A pulsar 70 is provided on the outside (front) of the pump gear 41G. The pulsar 70 is fixed to the drive shaft 41S of the supply pump 41, and is configured to rotate with the rotation of the drive shaft 41S. On the outer peripheral surface of the pulsar 70, an output projection 70a as a detected portion is formed every 90 °. An extra tooth 70b is formed on the circumferential surface of the pulsar 70, for example, immediately before the output projection 70a corresponding to the top dead center of the first cylinder (on the upstream side of rotation).

  On the outer peripheral side of the pulsar 70, a cam angle sensor 71 serving as a rotation angle detecting means is disposed close to the output projection 70a and the extra teeth 70b. The cam angle sensor 71 is for detecting the rotation angle of the camshaft 18 (cam gear 18G). As the camshaft 18 rotates, the cam gear 18G, the pump gear 41G, and the drive shaft 41S of the supply pump 41 rotate. Accordingly, the pulsar 70 is rotated, and the output projection 70a and the extra teeth 70b of the pulsar 70 pass through the vicinity thereof, so that a rotation angle signal is output.

  The cam angle sensor 71 is disposed in a hole 7 a provided in the gear case 7. The hole 7a formed in the gear case 7 is provided to face the detected portion (the output protrusion 70a and the extra teeth 70b) of the pulsar 70. For this reason, the front end side of the cam angle sensor 71 fitted and mounted in the hole 7a faces the detected portion of the pulsar 70 and can detect the passage of the detected portion. The base side of the cam angle sensor 71 is exposed outside the gear case 7.

  With this configuration, the cam angle sensor 71 is partly housed in the gear case 7 as compared with the case where the cam angle sensor 71 is provided outside the gear case 7. The portion protruding forward is reduced, and the size of the entire engine can be reduced.

  In the present embodiment, the pulsar 70 is provided with the output protrusions 70a and the extra teeth 70b as the detected portions on the outer peripheral surface thereof, but is not limited thereto. For example, the pulsar 70 is configured in a disk shape. It is also possible to provide a structure in which perforations are provided on the surface every 90 °, and an extra hole is provided on the surface of the pulsar just before the perforation corresponding to the top dead center of the first cylinder (on the upstream side of rotation). .

As described above, the diesel engine 100 includes the gear case flange 5, the gear case 7 covering the outside of the gear case flange 5, the supply pump 41 fixed to the gear case flange 5, and the pump gear fixed to the drive shaft 41S of the supply pump 41. 41G and a cam gear 18G that meshes with the pump gear 41G and is fixed to the camshaft 18. The pump gear 41G and the cam gear 18G are constituted by a helical gear, and are used for detecting a cam angle outside the pump gear 41G. A pulsar 70 is provided, and a cam angle sensor 71 is disposed close to the outer peripheral side of the pulsar 70.
With this configuration, the pump gear 41G is applied with a force toward the rear side, so that the pulsar 70 does not move forward, and an error occurs in the distance between the cam angle sensor 71 and the pulsar 70. The cam angle can be accurately measured.

The cam angle sensor 71 is supported by the gear case 7.
With this configuration, the cam angle sensor 71 is partially housed in the gear case 7, thereby reducing the size of the entire engine.

The pump gear 41G is disposed above the cam gear 18G and at a position inclined in the left-right direction.
By configuring in this manner, the arrangement in the height direction can be made compact by tilting the pump gear 41G right and left as compared with the case where the pump gear 41G is arranged directly above the cam gear 18G. Can be reduced.

DESCRIPTION OF SYMBOLS 100 Diesel engine 1 Engine main part 2 Intake path 3 Exhaust path 4 Common rail system 5 Gear case flange 7 Gear case 7a Hole 14 Crank shaft 14G Crank gear 17 Idle shaft 17G Idle gear 18 Cam shaft 18G Cam gear 41 Supply pump 41G Pump gear 41S Drive shaft 42 Rail 43 Injector 70 Pulsar 71 Cam angle sensor (rotation angle detection means)

Claims (3)

A gear case flange,
A gear case covering the outside of the gear case flange;
A supply pump fixed to the gear case flange;
A pump gear fixed to a drive shaft of the supply pump;
A gear that meshes with the pump gear and is fixed to the camshaft,
The pump gear and the cam gear are composed of helical gears,
An engine characterized in that a pulsar for detecting a cam angle is provided outside the pump gear, and a rotation angle detecting means is arranged close to the outer peripheral side of the pulsar. The engine according to claim 1, wherein the rotation angle detection unit is supported by the gear case. The engine according to claim 1, wherein the pump gear is disposed above the cam gear and at a position inclined in the left-right direction.

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