JP2020002807A - diesel engine - Google Patents

Abstract

To provide a diesel engine capable of suppressing the freezing of a fuel metering rack 4 at cold time.SOLUTION: The diesel engine includes a fuel injection pump having the fuel metering rack, an oil supply passage 6, a pump direction oil outlet 7, and an oil valve 8. When the engine temperature is equal to or lower than a predetermined temperature, the oil valve 8, which is opened/closed according to the rise/drop of an engine temperature, is kept in the state of being opened so that engine oil 9 in the oil supply passage 6 is injected from the pump direction oil outlet 7 to the fuel injection pump 5. When the engine temperature is higher than the predetermined temperature, the oil valve 8 comes into the state of being closed so that the injection of the engine oil 9 from the pump direction oil outlet 7 is stopped.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a diesel engine, and more particularly, to a diesel engine capable of suppressing icing of a fuel metering rack in cold weather.

  2. Description of the Related Art Conventionally, there is a diesel engine equipped with a fuel injection pump having a fuel metering rack (for example, see Patent Document 1).

Japanese Utility Model Laid-Open Publication No. 5-77523 (see FIGS. 1 and 2)

  In the case of Patent Document 1, when the engine is stopped for a short time in cold weather, the fuel metering rack is stopped after the engine stops due to the moisture in the blow-by gas attached to the fuel metering rack of the fuel injection pump during engine operation. Easy to freeze. In this case, it becomes difficult to restart the engine and to control the fuel metering after the restart.

  An object of the present invention is to provide a diesel engine capable of suppressing icing of a fuel metering rack in cold weather.

According to the present invention, the oil valve is opened and closed in accordance with the rise and fall of the engine temperature. When the engine temperature is equal to or lower than the predetermined temperature, the oil valve is maintained in the open state, so that the engine oil in the oil supply path is pumped. Injection is made from the directional oil outlet toward the fuel injection pump, and when the engine temperature exceeds a predetermined temperature, the oil valve is closed so that the injection of engine oil from the pump directional oil outlet is stopped. Have been.
The second oil valve is also opened / closed in accordance with the rise and fall of the engine temperature. When the engine temperature is equal to or lower than a predetermined temperature, the second oil valve is maintained in a closed state, so that the second oil valve is closed from the piston-directed oil outlet. When the injection of engine oil is stopped and the engine temperature exceeds a predetermined temperature, the second oil valve is opened, whereby engine oil in the oil supply path is injected from the piston-directed oil outlet toward the piston. It is desirable to be constituted as follows.

According to the present invention, the following effects can be obtained.
When the engine is started in cold weather, while the engine temperature is lower than the predetermined temperature, the engine oil in the oil supply path is injected from the pump-directed oil outlet toward the fuel injection pump, and the engine oil adheres to the fuel metering rack. Moisture in the blow-by gas is prevented from adhering to the fuel metering rack, and even if the engine is stopped after a short period of operation, the fuel metering rack is hardly frozen, and the freezing of the fuel metering rack in cold weather is suppressed. Can be. For this reason, the restart of the engine and the fuel adjustment control after the restart can be performed without any trouble.
Further, after the engine is started, the engine operation is continued, and when the engine temperature exceeds a predetermined temperature, the injection of the engine oil from the pump-directed oil outlet is stopped, and the so-called oil rise, in which the engine oil enters the inside of the fuel injection pump, occurs. Is prevented.

FIG. 1A is a longitudinal sectional front view of a pair of oil valves used in the engine according to the embodiment of the present invention and a peripheral portion thereof, and FIG. 1B is a sectional view taken along line BB of FIG. 1A. FIG. 2A is a longitudinal sectional front view of the engine according to the embodiment of the present invention, and FIG. 2B is an enlarged view of a portion B in FIG. 2A.

  FIGS. 1 and 2 are diagrams illustrating an engine according to an embodiment of the present invention. In this embodiment, a sub-chamber type water-cooled vertical in-line four-cylinder diesel engine will be described.

  As shown in FIG. 2 (A), the engine is mounted on a cylinder block (15), a cylinder head (16) mounted on the upper part of the cylinder block (15), and mounted on an upper part of the cylinder head (16). It has a cylinder head cover (17) and an oil pan (18) attached to the lower part of the cylinder block (15).

  As shown in FIG. 2 (A), the cylinder block (15) includes a cylinder (19), a pump housing chamber (20), a valve operating cam chamber (21), a tappet chamber (22), and a crankcase (23). It is an integrally molded product. The piston (12) is fitted in the cylinder portion (19), and a cylinder water jacket (24) is provided. A crankshaft (25) is housed in the crankcase (23), and the crankshaft (25) is linked to the piston (12) via a connecting rod (26).

  As shown in FIG. 2A, a fuel injection pump (5) and a fuel injection camshaft (28) are housed in a pump housing chamber (20), and a swirl chamber (29) and a head water jacket are provided in a cylinder head (16). (30) is provided. A fuel injection valve (31) is inserted into the vortex chamber (29), and a fuel injection pipe (32) derived from a fuel injection pump (5) is connected to the fuel injection valve (31).

  As shown in FIG. 2A, an intake port (33) is provided in the cylinder head (16), an intake valve (34) is provided in the intake port (33), and a valve operating chamber is provided in the valve operating cam chamber (21). The camshaft (27) is housed, the tappet (37) is housed in the tappet chamber (22), the rocker arm (38) is housed in the cylinder head cover (17), and the tappet (37) is moved from the valve gear camshaft (27). The intake valve (34) is driven via the push rod (39) and the rocker arm (38) in order. The exhaust port (not shown) is driven in the same manner.

  This engine includes a fuel injection pump (5) having a fuel metering rack (4) as shown in FIG. 2A, an oil supply path (6) as shown in FIG. A directional oil outlet (7) and an oil valve (8) are provided. As shown in FIG. 1A, the oil valve (8) is opened and closed according to the rise and fall of the engine temperature. In this case, the oil valve (8) is maintained in the open state, so that the engine oil (9) in the oil supply path (6) is directed from the pump-directed oil outlet (7) to the fuel injection pump (5). When the engine temperature exceeds a predetermined temperature, the oil valve (8) is closed to stop the injection of the engine oil (9) from the pump-directed oil outlet (7). ing.

For this reason, when the engine is started in cold weather, while the engine temperature is equal to or lower than the predetermined temperature, the engine oil (9) in the oil supply passage (6) is turned into the pump-directed oil as shown in FIGS. The fuel is injected from the outlet (7) toward the fuel injection pump (5), the engine oil (9) adheres to the fuel metering rack (4), and the moisture in the blow-by gas adheres to the fuel metering rack (4). Therefore, even if the engine is stopped after a short time of operation, the fuel metering rack (4) hardly freezes, and the freezing of the fuel metering rack (4) in cold weather can be suppressed. For this reason, the restart of the engine and the fuel adjustment control after the restart can be performed without any trouble.
Further, after the engine is started, the engine operation is continued, and when the engine temperature exceeds a predetermined temperature, the injection of the engine oil (9) from the pump-directed oil outlet (7) is stopped, and the engine oil (9) is supplied to the fuel injection pump. The so-called oil rise that enters the inside of (5) is prevented.

  As shown in FIGS. 2 (A) and 2 (B), this engine uses a piston (12), a piston-directed oil outlet (10), and a first oil valve (8) as the first oil valve. In addition to the valve (8), a second oil valve (11) is provided, and the second oil valve (11) is also opened and closed according to the rise and fall of the engine temperature. When the engine temperature is lower than a predetermined temperature, As shown in FIGS. 2A and 2B, the injection of engine oil (9) from the piston-directed oil outlet (10) is prevented by keeping the second oil valve (11) closed. When the engine temperature exceeds a predetermined temperature, the second oil valve (11) is opened, and the engine oil (9) in the oil supply path (6) is moved from the piston-directed oil outlet (10) to the piston. It is configured to be injected toward (12).

For this reason, when the engine is started in cold weather, while the engine temperature is equal to or lower than the predetermined temperature, as shown in FIGS. The injection is prevented, and the supercooling of the piston (12) and the generation of excessive piston clearance due to the supercooling of the piston (12) are suppressed. For this reason, generation of piston slap noise and leakage of blow-by gas can be suppressed.
Further, after the engine is started, the engine operation is continued, and when the engine temperature exceeds a predetermined temperature, the engine oil (9) in the oil supply path (6) is injected from the piston-directed oil outlet (10) toward the piston (12). Therefore, the cooling of the piston (12) after the engine is warmed up is performed without any trouble.

In this engine, as shown in FIGS. 1A and 1B, one of the first oil valve (8) and the second oil valve (11) is open. During the interval, the other oil valve (11) is configured to be closed.
For this reason, it is difficult for both oil valves (8) and (11) to be simultaneously opened, and it is possible to prevent insufficient injection due to a decrease in the injection pressure of the engine oil (9).

Each of the first oil valve (8) and the second oil valve (11) is composed of a temperature-sensitive deformable member that deforms by receiving heat from the engine.
Therefore, it is not necessary to control the opening and closing of the oil valves (8) and (11) by electronic control, and the oil valves (8) and (11) can be easily controlled.

The temperature-sensitive deformable member is a bimetal.
The temperature-sensitive deformable member may be a shape memory alloy.

As shown in FIGS. 2A and 2B, an oil supply path (6), a pump-directed oil outlet (7), a first oil valve (8), a piston-directed oil outlet (10), The second oil valve (11) is provided on a bearing case (40) that supports a metal bearing (not shown) of the crankshaft (25).
The oil supply passage (6) communicates with an oil gallery (not shown) for supplying engine oil of an oil pan (18) to a sliding portion such as a bearing of a crankshaft (25).
As shown in FIG. 2A, a pair of left and right oil valve receiving holes (41) and (42) are provided in the bearing case (40) when viewed in a direction parallel to the center axis (25a) of the crankshaft (25). The first oil valve housing hole (41) is separated from the center axis (25a) of the crankshaft (25) toward the fuel injection pump (5), and the second oil valve housing hole (42) is Is closer to the center axis (25a) of the crankshaft (25) than the oil valve housing hole (41).
As shown in FIG. 2 (B), when viewed in a direction parallel to the central axis (25a) of the crankshaft (25), the first oil valve housing hole (41) is formed on the upper surface (40a) of the bearing case (40). ) From the upper surface (40a) of the bearing case (40) to the crankshaft (25). ) Is inclined downward toward the side away from the central axis (25a).

As shown in FIGS. 1 (A) and 1 (B), the first oil valve accommodation hole (41) is provided with a first lid (41a), a first valve accommodation chamber (41b), and a first valve. A support (41c) and a first oil valve (8) are provided.
The first lid (41a) is disk-shaped, has a pump-directed oil outlet (7) at the center, is fitted and fixed in the first oil valve housing hole (41), and has a first oil valve housing. On the inner bottom side of the hole (41), a first valve storage chamber (41b) covered with a first lid (41a) is formed.
A plurality of (specifically, four) first valve supports (41c) are provided at predetermined intervals in the circumferential direction of the first oil valve housing hole (41), and the first oil valve housing hole (41c) is provided. A first valve engaging recess (41d) formed long in the axial direction of (41) and facing the center of the first oil valve housing hole (41).

As shown in FIGS. 1 (A) and 1 (B), the first oil valve (8) has a disk shape, and its outer peripheral edge is fitted inside the plurality of first valve engagement recesses (41d). It is supported by one valve support (41c).
The first oil valve (8) is provided with a first valve body (8a) fitted in the pump-directed oil outlet (7) at the center of the upper surface. This first valve body (8a) is made of rubber. When the engine temperature is equal to or lower than a predetermined temperature (for example, 0 ° C.), the first oil valve (8) is curved downward and the first valve body (8a) is connected to the pump-directed oil outlet (7). When the engine temperature exceeds a predetermined temperature (for example, 0 ° C.) while the valve is open, the first oil valve (8) curves upward and the first valve body (8a) is pumped. The valve is in a closed state in which it is fitted inside the directional oil outlet (7).
As shown in FIG. 2 (A), a communication hole (35) is provided between the crankcase (23) and the pump accommodating chamber (20), and the engine is injected from the pump-directed oil outlet (7). The oil (9) reaches the fuel metering rack (4) of the fuel injection pump (5) through the communication hole (35).
As shown in FIG. 2 (A), a communication hole (35) is provided between the crankcase (23) and the pump accommodating chamber (20), and an engine injected from the pump-directed oil outlet (7). The oil (9) reaches the fuel metering rack (4) of the fuel injection pump (5) through the communication hole (35).

As shown in FIG. 1A, the second oil valve receiving hole (42) is provided with a second lid (42a), a second valve receiving chamber (42b), and a second valve support ( 42c) and a second oil valve (11).
The second lid (42a) is disk-shaped, has a piston-directed oil outlet (10) at the center, is fitted and fixed in the second oil valve receiving hole (42), and has a second oil valve receiving portion. A second valve accommodating chamber (42b) covered with a second lid (42a) is formed on the inner bottom side of the hole (42).
A plurality of (specifically, four) second valve support bodies (42c) are provided at predetermined intervals in the circumferential direction of the second oil valve housing hole (42), and the second oil valve housing hole (42c) is provided. A second valve engaging recess (42d) formed long in the axial direction of (42) and facing the center of the second oil valve housing hole (42).

As shown in FIG. 1 (A), the second oil valve (11) is disk-shaped, and its outer peripheral edge is fitted inside the plurality of second valve engaging recesses (42d), It is supported by the support (42c).
The second oil valve (11) has a second valve body (11a) fitted in the piston-directed oil outlet (10) at the center of the upper surface. This second valve body (11a) is made of rubber. When the engine temperature is equal to or lower than a predetermined temperature (for example, 0 ° C.), the second oil valve (11) is curved upward and the second valve body (11a) is connected to the piston-directed oil outlet (10). When the engine temperature exceeds a predetermined temperature (for example, 0 ° C.), the second oil valve (11) bends downward and the second valve body (11a) is closed. The valve is opened from the piston-directed oil outlet (10).

  (4) Fuel metering rack, (5) Fuel injection pump, (6) Oil supply path, (7) Pump-directed oil outlet, (8) First oil valve, (9) Engine oil (10) Piston-directed oil outlet, (11) Second oil valve, (12) Piston.

Claims (6)

  A fuel injection pump (5) having a fuel metering rack (4), an oil supply path (6), a pump-directed oil outlet (7), and an oil valve (8) are provided. When the engine temperature is lower than a predetermined temperature, the oil valve (8) is kept open so that the engine oil (9) in the oil supply passage (6) is pumped. The oil is injected from the directional oil outlet (7) toward the fuel injection pump (5), and when the engine temperature exceeds a predetermined temperature, the oil valve (8) is closed so that the oil is released from the pump directional oil outlet (7). A diesel engine configured to stop injection of the engine oil (9). The diesel engine according to claim 1,
A piston (12), a piston-directed oil outlet (10), and a second oil valve (11) separately from the first oil valve (8) using the oil valve as a first oil valve (8). The second oil valve (11) is also opened and closed according to the rise and fall of the engine temperature. When the engine temperature is equal to or lower than a predetermined temperature, the second oil valve (11) is maintained in a closed state. As a result, the injection of the engine oil (9) from the piston-directed oil outlet (10) is prevented, and when the engine temperature exceeds a predetermined temperature, the second oil valve (11) is opened, whereby the oil supply is started. A diesel engine, characterized in that engine oil (9) in a path (6) is configured to be injected from a piston-directed oil outlet (10) toward a piston (12). The diesel engine according to claim 2,
While one of the first oil valve (8) and the second oil valve (11) is in the open state, the other oil valve (11) is in the closed state. A diesel engine characterized in that: The diesel engine according to claim 1,
A diesel engine, wherein the oil valve (8) is formed of a temperature-sensitive deformable member that deforms by receiving heat from the engine. In the diesel engine according to claim 2 or 3,
A diesel engine, wherein each of the first oil valve (8) and the second oil valve (11) is constituted by a temperature-sensitive deformable member that deforms by receiving heat from the engine. In the diesel engine according to claim 4 or claim 5,
A diesel engine, wherein the temperature-sensitive deformable member is one of a bimetal and a shape memory alloy.

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