JP2021080871A - diesel engine - Google Patents

Abstract

To provide a diesel engine in which a setting time of an engine actual rotation number after the release of a load becomes short.SOLUTION: A mechanical governor defines a quantity increase limit 2a of a fuel metering rack of a fuel injection pump in a rack position, an electronic governor controls the rack position on the basis of an isochronous control characteristic at a fuel quantity reduction side rather than the quantity increase limit 2a, raises a current value applied to an actuator by PID control or PI control at a load input 9, and moves the rack position to a quantity increase side. The electronic governor comprises an upper limit restriction map, and in an ultra-rated rotation region, an upper limit of the current value exceeding the quantity increase limit 2a is limited to an upper limit restriction value 3c which is inputted into the upper limit restriction map.SELECTED DRAWING: Figure 2

Description

The present invention relates to a diesel engine, and more particularly to a diesel engine in which the setting time of the actual engine speed after the load is released is shortened.

Conventionally, a fuel injection pump, a mechanical governor, and an electronic governor are provided. The mechanical governor sets a limit for increasing the rack position of the fuel metering rack of the fuel injection pump, and droop control is performed in the super-rated rotation range exceeding the rated rotation speed. There is a diesel engine that defines the weight increase limit based on the characteristics, and the electronic governor is configured to control the rack position based on the isochronous control characteristics on the fuel weight reduction side of the weight increase limit (for example, patent documents). 1).

Japanese Unexamined Patent Publication No. 2000-45798 (see FIGS. 1 (A) and 2)

<< Problem >> It may take a long time to set the engine speed after the load is released.
In the engine of Patent Document 1, the setting time of the actual engine speed after the load is released may be long in the super-rated rotation region.

An object of the present invention is to provide a diesel engine in which the setting time of the actual engine speed after the load is released is shortened.

The main configurations of the present invention are as follows.
As illustrated in FIG. 1, the electronic governor (3) is provided with an upper limit limit map (3b), and as illustrated in FIG. 2, in the super-rated rotation region, the upper limit of the current value exceeding the increase limit (2a) is set. A diesel engine characterized in that it is configured to be limited to the upper limit limit value (3c) entered in the upper limit limit map (3b) (see FIG. 1).

The invention of the present application has the following effects.
<< Effect >> The settling time of the actual engine speed after the load is released is shortened.
As illustrated in FIG. 2, since the upper limit of the current value exceeding the increase limit (2a) is limited by the upper limit limit value (3c), the load is released as shown in the graph (solid line) illustrated in FIG. 3 (A). After (10), the settling time (T0) of the actual engine speed becomes shorter.

It is a schematic diagram of the fuel metering apparatus of the engine which concerns on embodiment of this invention. It is a graph of the engine rotation speed, the rack position, and the current value of the apparatus of FIG. FIG. 3A is a time chart of the actual engine speed under the control of the device of FIG. 1, and FIG. 3B is a time chart of the integrated value under the control of the device of FIG.

1 to 3 are views for explaining a diesel engine according to an embodiment of the present invention, and in this embodiment, a vertical multi-cylinder diesel engine will be described.

As shown in FIG. 1, this diesel engine includes a fuel injection pump (1), a mechanical governor (2), and an electronic governor (3).
The mechanical governor (2) sets an increase limit (2a) (see FIG. 2) of the rack position of the fuel metering rack (1a) of the fuel injection pump (1), and exceeds the rated rotation speed as shown in FIG. In the super-rated rotation region, the increase limit (2a) is set based on the droop control characteristic in which the actual engine speed decreases as the rack position moves to the increase side due to the load injection (9).

As shown in FIG. 1, the electronic governor (3) includes an actuator (3a), and as shown in FIG. 2, the actual engine speed is on the fuel reduction side of the increase limit (2a) regardless of the load fluctuation. The rack position is controlled based on the isochronous control characteristic that maintains the engine at a constant engine speed (TR), and at the time of load application (9), the current value applied to the actuator (3a) is controlled by PID control or PI control. It is configured to be raised and the rack position to be moved to the increase side.

As shown in FIG. 1, the electronic governor (3) has an upper limit limit map (3b), and as shown in FIG. 2, in the super-rated rotation region, the upper limit of the current value exceeding the increase limit (2a) is the upper limit. It is configured to be limited to the upper limit value (3c) entered in the limit map (3b) (see FIG. 1).

As shown in FIG. 2, according to this engine, the upper limit of the current value exceeding the increase limit (2a) is limited by the upper limit limit value (3c), so that the graph (solid line) shown in FIG. 3A is shown. In addition, the settling time (T0) of the actual engine speed after the load release (10) is shortened.

The reason is presumed as follows.
As shown in FIG. 2, the actual engine speed decreases due to the load application (9) during control by the electronic governor (3) set to a predetermined engine target speed (TR) in the super-rated speed region. The value of the current applied to the actuator (3a) rises, and the rack position moves to the increase side based on the isochronous control characteristics as shown by the arrow. Further, when the rack position moves to the increase side and reaches the increase limit (2a) defined by the mechanical governor (2), the control by the mechanical governor (2) becomes dominant, and the engine actual based on the droop control characteristics. Since the rotation speed decreases and the rotation speed deviation (11) between the engine target rotation speed (TR) and the engine actual rotation speed occurs, the current value applied to the actuator (3a) reaches the rack position increase limit (2a). Beyond, it rises regardless of the metering of the rack position.

In such a case, as shown in the graph (dashed line) shown in FIG. 2, in the conventional product in which there is no special limit on the upper limit of the current value exceeding the increase limit (2a), the increase operation limit value of the actuator (3a) As the current value rises to, and the current rise time becomes longer, the integrated rise value (R1) becomes higher as shown in the graph (dashed-dotted line) shown in FIG. 3 (B), and is shown in FIG. 3 (A). As shown in the graph (dashed line), it takes time to cancel the integrated value after the load is released (10), the actual engine current speed overshoots significantly, and the settling time of the actual engine speed after the load is released (10). (T1) is long.

On the other hand, in the present embodiment, as shown in FIG. 2, since the upper limit of the current value exceeding the increase limit (2a) is limited by the upper limit limit value (3c), the current increase value becomes lower and the current increase time becomes lower. As the length becomes shorter, the integrated increase value (R0) becomes lower as shown in the graph (solid line) shown in FIG. 3 (B), and after the load is released (10) as shown in the graph (solid line) shown in FIG. 3 (A). It does not take time to cancel the integrated value of, the overshoot of the actual rotation speed is small, and the settling time (T0) of the actual engine speed after the load release (10) is shortened.

As shown in FIG. 1, the mechanical governor (2) is located between the governor lever (4), the accelerator operating means (5) fixed at the maximum rotation speed setting position, and between the governor lever (4) and the accelerator operating means (5). It is equipped with a governor spring (6) erected in the governor and a governor force generating means (7) linked to the governor lever (4).
The electronic governor (3) includes an actuator (3a) and an electronic control device (8) that controls the actuator (3a).
This engine is configured so that the governor lever (4) and the actuator (3a) receive the metering rack (1a) on the fuel increasing side, respectively, and in the super-rated rotation region shown in FIG. 2, the input is input to the upper limit limit map (3b). Based on the upper limit value (3c), the separation distance (3d) of the output unit (3e) of the actuator (3a) from the metering rack (1a) received by the governor lever (4) shown in FIG. 1 is limited. It is configured to be.

According to this engine, in the super-rated rotation region shown in FIG. 2, the separation distance of the output unit (3e) of the actuator (3a) from the fuel metering rack (1a) received by the governor lever (4) shown in FIG. 1 (3d) is shortened, the output unit (3e) returns quickly after the load is released (10), and the rack position can be quickly returned to the fuel reduction side. As described above, the settling time (T0) of the actual engine speed after the load release (10) is shortened.

As shown in FIG. 1, the fuel injection pump (1) is a row-type plunger type fuel injection pump, and is a diagonal groove of the plunger (12) due to the movement of the rack position in the fuel increase / decrease direction of the fuel metering rack (1a). The relative positions of the relief holes (13a) of (12a) and the barrel (13) in the circumferential direction are adjusted to adjust the fuel injection amount.
The plunger (12) is driven up and down by the fuel injection cam (15) via the tappet (14).

As shown in FIG. 1, the accelerator operating means (5) of the mechanical governor (2) is an accelerator lever. A spring force (6a) acting from the governor spring (6) toward the fuel increasing side acts on the governor lever (4). The governor force generating means (7) includes a centrifugal governor weight (7a) and a governor sleeve (7b) that are rotationally driven by a crank shaft (16), and when the actual engine speed increases, the centrifugal governor weight (7a) Is widened, and a governor force (7c) acting in the direction of fuel reduction acts on the governor lever (4) via the slide of the governor sleeve (7b). The governor lever (4) receives the fuel metering rack (1a) urged in the fuel increasing direction by the urging force (17a) of the urging spring (17) from the fuel increasing side, and the spring force from the governor spring (6). The rack position is controlled by the governor lever (4) that swings due to the disproportionate force between (6a) and the governor force (7c), and the rack position increase limit (2a) (see FIG. 2) is determined.

The electronic control device (8) of the electronic governor (3) shown in FIG. 1 is an engine ECU. The ECU is an abbreviation for an electronic control unit, and a microcomputer is used.
A linear solenoid is used for the actuator (3a). The linear solenoid has an output unit (3e) protruding from the actuator body (3f), and as the applied current value increases, the output unit (3e) is largely drawn into the actuator body (3f). An output rod is used for the output unit (3e).
The upper limit limit map (3b) is stored in a storage unit built in the electronic control device (8). A non-volatile memory such as a flash memory, P-ROM, EP-ROM, or E2P-ROM is used as the storage unit.

As shown in FIG. 1, the electronic control device (8) includes an accelerator sensor (18a) that detects the accelerator opening from the depressed position of the accelerator pedal (18), and a flywheel (19) of the crankshaft (16). The rotation detection sensor (20a) that detects the passage of the serrated protrusions provided on the entire circumference of the rotation detection disk (20) provided is linked, and the engine target rotation speed (RT) (RT) based on the detection of the accelerator opening is linked. The rack position is controlled by the actuator (3a) so as to reduce the rotation speed deviation (11) (see FIG. 2) of the actual engine speed based on the detection of the rotation detection sensor (20a) and the rotation speed detection sensor (20a).

The actuator (3a) shown in FIG. 1 uses an urging spring (17) until the rack position reaches the increase limit (2a) (see FIG. 2) defined by the mechanical governor (2) by loading (9). The fuel metering rack (1a) urged in the fuel increasing direction is received by the output unit (3e) from the fuel increasing side, and the rack position is controlled. After that, when the actual engine speed decreases, the current value applied to the actuator (3a) (see FIG. 1) rises beyond the rack position increase limit (2a), and the output unit (3e) shown in FIG. 1 increases. It is pulled toward the actuator body (3f) side, and the output unit (3e) is separated from the fuel metering rack (1a) received by the governor lever (4).
As shown in FIG. 2, the rising current value is limited to the upper limit limit value (3c) input in the upper limit limit map (3b) (see FIG. 1). The upper limit value (3c) gradually decreases as the engine target rotation speed increases from the rated rotation speed side to the no-load maximum rotation speed side.

(1) ... Fuel injection pump, (1a) ... Fuel metering rack, (2) ... Mechanical governor, (2a) ... Weight increase limit, (3) ... Electronic governor, (3a) ... Actuator, (3b) ... Upper limit limit Map, (3c) ... upper limit limit value, (3d) ... separation distance, (3e) ... output unit, (4) ... governor lever, (5) ... accelerator operating means, (6) ... governor spring, (7) ... governor Force generating means, (8) ... Electronic control device, (TR) ... Engine target rotation speed.

Claims (2)

It is equipped with a fuel injection pump (1), a mechanical governor (2), and an electronic governor (3).
The mechanical governor (2) sets an increase limit (2a) of the rack position of the fuel metering rack (1a) of the fuel injection pump (1), and in the super-rated rotation range exceeding the rated rotation speed, the load is applied (9). , The increase limit (2a) is set based on the droop control characteristic that the actual engine speed decreases as the rack position moves to the increase side.
The electronic governor (3) is provided with an actuator (3a) and is isochronous that maintains the actual engine speed at a constant engine target speed (TR) on the fuel reduction side of the increase limit (2a) regardless of load fluctuations. The rack position is controlled based on the control characteristics, and at the time of load application (9), the current value applied to the actuator (3a) is increased by PID control or PI control, and the rack position is moved to the increase side. Being done
The electronic governor (3) is provided with an upper limit limit map (3b), and in the super-rated rotation region, the upper limit of the current value exceeding the increase limit (2a) is the upper limit limit value (3c) input to the upper limit limit map (3b). ) Is configured to be a diesel engine. In the diesel engine according to claim 1,
The mechanical governor (2) is a governor lever (4), an accelerator operating means (5) fixed at the maximum rotation speed setting position, and a governor spring (5) installed between the governor lever (4) and the accelerator operating means (5). 6) and a governor force generating means (7) linked to the governor lever (4) are provided.
The electronic governor (3) includes an actuator (3a) and an electronic control device (8) that controls the actuator (3a).
The governor lever (4) and actuator (3a) are configured to receive the metering rack (1a) on the fuel increase side, respectively. In the super-rated rotation region, the upper limit limit value (3c) entered in the upper limit limit map (3b). Based on the above, the distance (3d) of the output unit (3e) of the actuator (3a) from the metering rack (1a) received by the governor lever (4) is limited. Diesel engine.

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