JP4747953B2 - Tractor - Google Patents

Description

The present invention relates to a tractor equipped with a common rail fuel injection control.

Since the fuel and the engine are cooled when the engine is started, the startability is poor, the rotation is not good, and black smoke is generated.
As means for preventing such a malfunction at the start of the engine, Japanese Patent Application Laid-Open No. 2005-282811 describes a technique for detecting the engine explosion state and increasing the fuel injection pressure. Japanese Patent No. 3083332 describes a technique for detecting the temperature of the engine itself and increasing the fuel injection pressure in a low temperature state at the time of starting.
JP-A-2005-282811 Japanese Patent No. 3083332

  In the technique described in Japanese Patent Application Laid-Open No. 2005-282181, an engine malfunction occurs temporarily because a violent explosion state is detected and controlled. In the technique described in Japanese Patent No. 3083332, even when the engine itself is cooled, the fuel injection pressure is increased and the fuel is used excessively when the outside air temperature is high and ignition is easy.

  Accordingly, an object of the present invention is to ensure stable rotation with an appropriate fuel consumption by detecting the outside air temperature and battery voltage at the time of starting the engine and controlling the injection pressure.

The above object of the present invention is achieved by the following configuration.
That is, the invention of claim 1 is a tractor capable of running on the road and cultivating on the cultivated land, and a droop control (B) mode in which the engine output is changed by the fluctuation of the engine speed due to the running load during the road running. The isochronous control (A) mode, which maintains the engine speed by changing the output with respect to the resistance during tillage work , can be automatically selected based on information from the GPS (41) , and the engine is connected to the common rail ( 11) is provided, said common rail (11) is provided with means for calculating the engine speed (N) and the output torque (T) from rail pressure (P), at the start of the engine, said the information from GPS (41) The droop control (B) mode or the isochronous control (A) mode is selected, the rail pressure (P) is set based on the control mode, and the temperature of the intake air to the engine And the voltage of the battery is measured. When the temperature of the intake air is less than a set temperature or when the voltage of the battery is less than a set voltage value, the rail pressure (P) is increased and changed. When the pressure (P) becomes equal to or higher than the set rail pressure, the tractor is provided with an engine control unit (17) for performing control for injecting fuel from the injector (10) to start the engine.

According to the first aspect of the invention, when the engine is started, first, the droop control (B) mode or the isochronous control (A) mode is automatically selected based on the information of the GPS (41), and based on the control mode. The rail pressure (P) is set, and then the temperature of the intake air to the engine is measured and the voltage of the battery is measured. If the temperature of the intake air is lower than the set temperature or the voltage of the battery is the set voltage value If the pressure is less than the value, the rail pressure (P) is raised and changed, and when the rail pressure exceeds the set rail pressure, the fuel is injected from the injector (10) and the engine is started. When the outside air temperature is low, the rail pressure is increased to increase the fuel injection pressure and promote fuel miniaturization to improve the ignitability of the fuel. Raw for it is no longer.

  Further, when the battery voltage V is low at the time of starting the engine, the rail pressure is increased to increase the fuel injection pressure to promote fuel miniaturization and improve the ignitability of the fuel. No black smoke is generated.

In addition, manual operation by the operator can be reduced by automatically switching to each control mode based on information from the GPS (41).

  First, the outline | summary is demonstrated about a pressure accumulation type fuel-injection diesel engine. The accumulator fuel-injection diesel engine performs fuel supply to an injector 10 that injects fuel into each cylinder through a common rail (accumulation chamber) 11 that is controlled to a required pressure. In the system diagram shown in FIG. The injection control state will be described.

  The fuel in the fuel tank 12 is sucked into the high pressure pump 9 driven by the engine through the fuel filter 14 through the suction passage 13, and the high pressure fuel pressurized by the high pressure pump 9 is referred to as an engine control unit (hereinafter referred to as "ECU"). ) The pressure is controlled by the inflow pressure control valve 20 on the basis of the command from 17 and is guided to the common rail 11 by the discharge passage 15 and stored.

  The high-pressure fuel in the common rail 11 is supplied to the injectors (fuel injection valves) 10 corresponding to the number of cylinders through the high-pressure fuel supply passages 16, and the solenoid valve of the injector 10 is opened for each cylinder based on a command from the ECU 17. The high pressure fuel is injected into each combustion chamber of the engine.

Excess fuel (return fuel) in each injector 10 is guided to a common return passage 19 by each return passage 18 and returned to the fuel tank 12.
A pressure control valve 22 is provided at the end of the common rail 11 in order to control the fuel pressure in the common rail 11 (common rail pressure). The pressure control valve 22 adjusts the return pressure of the return passage 19 for surplus fuel to the fuel tank 12 based on a duty signal from the ECU 17, thereby controlling the fuel discharge pressure in the common rail 11. Specifically, the target common rail pressure is set according to the engine operating conditions, and the inflow pressure control valve 20 and the pressure control valve 22 are set so that the common rail pressure detected by the common rail pressure sensor 21 matches the target common rail pressure. Control the opening.

FIG. 7 is a signal input / output control block diagram of the ECU 17.
A shift signal from the potentiometer 23 that detects the rotation position of the manual shift lever and a shift signal from the potentiometer 24 that detects the rotation position of the foot pedal are input to the ECU 17. The engine speed from the engine speed sensor 42, the injection timing of the cylinder burning from the cylinder discrimination sensor 25, the compressed air pressure from the intake air turbo pressure sensor 26, and the outside air sucked from the intake temperature sensor 27 The temperature is the temperature of the cooling water from the radiator water temperature sensor 28, the amount of air sucked by the turbo from the intake air amount sensor 29, the rail pressure P from the common rail pressure sensor 21, and the fuel injection time of the injector 30 from the timer 30. The traveling speed of the work implement from the speed sensor 31, the brake action signal from the brake sensor 32, the in-cylinder pressure fluctuation value from the in-cylinder pressure sensor 37 attached to the cylinder head, and the piston position information of each cylinder from the crank angle sensor 38. When connecting on the road by connecting brake pedals provided separately on the left and right The signal from the imaging sensor 39, the signal from the working machine output sensor 40 and drives the working machine further GPS work position information of the working machine from the (global positioning system) 41 is inputted to the ECU 17.

  The ECU 17 outputs a glow plug control 33 signal, an injector control 34 signal, a common rail pressure control 35 signal, a traveling clutch control 36 signal, and a brake control 43 signal.

In relation to the engine speed N and the output torque T, the ECU 17 is provided with three types of control modes: isochronous control A, droop control B, and heavy load control C shown in FIG.
The isochronous control A is a control for changing the output according to the load so that the rotation speed becomes constant even if the load fluctuates, and the rotation speed of the manual shift lever, that is, the set rotation speed is changed by the lever potentiometer 23. And used for normal farming. For example, if it is a combine, it is a harvesting work, and if it is a tractor, it is a cultivating work. Since the rotation speed is maintained, the driver can easily operate while maintaining the optimum working state. The output is varied by changing the fuel injection amount to the injector 10 and changing the injection timing with the injector control 34 signal and the common rail pressure control 35 signal.

  Droop control B is a control in which the output fluctuates due to fluctuations in the rotation speed due to the load. When the foot pedal potentiometer 24 is rotated by stepping on the foot pedal, the rotation speed is changed, so that traveling without farming is performed. Used for. When traveling for mere movement, for example, if braking is applied to reduce or stop the traveling speed, the engine speed decreases as the traveling load increases. In addition, the stop can be performed safely, and for example, the operator can detect the load state of the engine when climbing.

  The heavy load control C is a control for increasing the output by increasing the rotational speed when the constant rotational speed cannot be maintained even if the output is changed according to the load by the isochronous control A, particularly near the engine load limit. Used when farming. For example, when the heavy load control C is used when a cultivating operation is performed with a tractor, especially when a heavy cultivated land is encountered, the engine output increases beyond a normal limit, so that the operation is not interrupted.

The heavy load control C may be used when the load is large and the vehicle is decelerated even though the speed is increased by the droop control B.
When working near the engine output limit, the engine speed increases, so the traveling speed also increases. To prevent this, it is only necessary to provide a transmission on the traveling transmission path and control the traveling speed to be constant. .

  Furthermore, the isochronous control A is a control used for normal work, the droop control B is a control used for driving on the road, and the heavy load control C is a control used when the work is particularly heavy. Since it is roughly determined by the geographical position of the work implement, manual operation of the operator can be reduced if the operation mode is automatically switched to each control mode based on the information from the GPS 41.

  The fuel injection of the injector 10 is performed by performing one or two pilot injections before the main injection to improve the startability. However, when the rotation is increased and only the main injection is switched, the main injection amount is changed. If it is increased linearly, the output torque will decrease as pilot injection disappears, so the main injection will increase rapidly step by step at the timing to stop this pilot injection to compensate for the output where pilot injection disappeared. The output torque fluctuation is prevented.

Next, the control state of the diesel engine will be described with a flowchart.
FIG. 1 shows the control at the start of the engine. In step S1, the control mode, that is, the isochronous control A, the droop control B or the heavy load control C is selected. The common real pressure is set in step S2 according to the selected control mode. In step S3, the temperature of the intake air is measured, and in step S4, the battery voltage is measured. If the intake air temperature determination in step S5 is, for example, less than 5 ° C, the set rail pressure in step S7 is increased and changed. If the battery voltage determination in step S6 is, for example, less than 11V, the set rail pressure in step S7 is increased. If the determination in step S5 and step S6 is “NO”, that is, if the intake air temperature is 5 ° C. or higher and the battery voltage is 11 V or higher, the set rail pressure is not changed. In step S8, the high pressure pump 9 is driven. If the rail pressure becomes equal to or higher than the set rail pressure in step S9, fuel is injected from the injector 10 in step S10 and the engine is started.

  In this way, when the intake air, that is, the outside air temperature is low or the battery voltage is low, by injecting the fuel into the cylinder at a high pressure, the fine atomization of the fuel is promoted and ignition is easy, and the startability is good. become.

  Since the injector injection timing of the ECU is controlled based on the detection result of the top dead center of the crank angle sensor 38, if the detection of the top dead center deviates, the injector injection timing deviates from the normal timing and is output. It becomes lower. FIG. 2 is a control for correcting a top dead center detection error due to an attachment error or the like of the crank angle sensor 38 with information from the in-cylinder pressure sensor 37. In step S11, the top dead center timing detected by the crank angle sensor 38 is stored in the ECU 17. When the engine rotation is stabilized in step S12 and the injection of the injector 10 is in a single injection state, the timing at which the cylinder pressure sensor 37 reaches the maximum internal pressure is detected in step S13. It is determined whether it coincides with the top dead center timing of the sensor 38. If there is an error, the top dead center timing stored in the ECU 17 is corrected in step S15.

  FIG. 3 is a control for correcting the injection timing and the injection amount of the injector 10 when the internal pressure of the cylinder is different from the pre-stored internal pressure data. It is effective in the case. In step S17, the injection timing and injection amount of the injector are read from the control map, in-cylinder pressure P stored in the ECU is read in step S18, the actual internal pressure is measured by the in-cylinder pressure sensor 37 in step S19, and the measured internal pressure is measured in step S20. If it exceeds the range of the predetermined error α, the injection timing and the injection amount of the injector are corrected in step S21.

  FIG. 4 is a control for preventing the turbo pressure of the intake air from becoming higher than a predetermined value and increasing NOx. In step S22, the rail pressure is read from the control map, and in step S23, the turbo pressure TP0 is read from the control map. In step S24, the turbo pressure sensor 26 measures the turbo pressure TP of the intake air. If the measured turbo pressure TP is larger than the set turbo pressure TP0 in the turbo pressure comparison in step S25, the rail pressure is reduced and the injection time is set in step S26. Increase the length to reduce NOx.

  When the work implement is driven on the road, it is possible to run at high speed. However, if the high speed run is performed during ground work, the vehicle body becomes unstable and dangerous. FIG. 5 is a control for limiting the maximum traveling speed. In step S28, the traveling speed is measured. If an ON signal is input from the work implement output sensor 40 in step S29, the process proceeds to the maximum speed limitation in step S31. Even if the ON signal is not input from the left and right brake connection sensor 39 in S30, the process shifts to the maximum speed limit in step S31 and travels in step S32. That is, even if the work machine is driven but not on the road, the maximum speed is limited to avoid danger.

The control described above can be applied to other internal combustion engines, for example, gasoline engines, regardless of diesel engines.
FIG. 9 shows the structure of the injector 10. A needle 51 is inserted into the nozzle body 50, and the needle 51 is slid by a solenoid 49 to inject fuel from the nozzle 55 at the nozzle tip 53.

  The nozzles 55 provided at the tip of the nozzle body 50 are provided in three or four circumferential directions, but the fuel supply passage 52 of the nozzle body 50 is supplied with a slight inclination in the axial direction from one side. Therefore, fuel injection from the nozzles 55 provided in the circumferential direction is not uniform, and combustion in the cylinder is biased.

  Therefore, in the embodiment shown in FIG. 10, a spiral groove 55 is provided in the fitting portion of the needle 51 to the nozzle body 50 to supply the fuel to the supply path 56 at the upper end of the groove 55 and supply the fuel to the fuel reservoir 54. A spiral rotational motion is given to the fuel so that the injection from the nozzle 55 is uniform in the circumferential direction. A similar effect can be expected even if a spiral groove is formed on the hole side of the nozzle body 50 in place of the groove 55 of the needle 51.

In the embodiment shown in FIG. 11, a fuel supply path 52 for sending fuel to the fuel reservoir 54 is formed in a spiral shape so as to surround the needle 51 so that the fuel swirls in the fuel reservoir 54.
In the embodiment shown in FIG. 12, guide fins 57 that are inclined with respect to the axial direction are provided at positions corresponding to the fuel reservoir 54 of the needle 51, and the fuel is swirled by the guide fins 57.

  FIG. 13 shows a structure in which nozzles at the nozzle tip 53 are doubled by changing the injection angle, and the upper and lower nozzles 55 and 58 are respectively arranged in three or four circumferential directions. In the pilot injection, fuel is mainly injected from the tip side nozzle 55, and the main injection is injected from both nozzles 55 and 58, so that the combustion state is improved.

  The embodiment shown in FIG. 14 is an embodiment in which the upper and lower nozzles 55 and 58 are separated from each other, and the fuel is pilot-injected from the upper nozzle 58 while the needle tip 60 is not completely removed from the fitting portion 59 at the tip of the nozzle body 50. Eventually, the needle tip 60 is removed from the fitting portion 59 at the tip of the nozzle body 50 and the fuel starts the main injection from the lower nozzle 55, thereby improving the initial ignition.

  FIG. 15 shows an embodiment in which a common rail 11 for a five-cylinder engine is used for a four-cylinder engine. A plug 61 is attached to one of the fuel supply holes to the injector 10 so that one kind of common rail 11 is used for the four-cylinder engine. It can be used for a five-cylinder engine and can reduce manufacturing costs.

Start control flowchart of the embodiment of the present invention Data correction control flowchart of the embodiment of the present invention Injection correction control flowchart of the embodiment of the present invention Rail pressure correction control flowchart of the embodiment of the present invention Maximum speed limit control flowchart of the embodiment of the present invention Schematic configuration diagram of an accumulator fuel injection diesel engine according to the present invention Control block diagram of an embodiment of the present invention Control mode diagram of an embodiment of the present invention Partial front sectional view of an embodiment of the present invention Partial enlarged front sectional view of an embodiment of the present invention Partial enlarged front sectional view of an embodiment of the present invention Partial enlarged front sectional view of an embodiment of the present invention Partial enlarged front sectional view of an embodiment of the present invention Partial enlarged front sectional view of an embodiment according to the present invention Perspective view of another embodiment of the present invention

N Engine speed T Output torque P Rail pressure A Intake air temperature V Battery voltage

Claims (1)

In tractor to enable tillage working with road and arable land,
A droop control (B) mode in which the engine output is changed by a change in engine speed due to a traveling load while traveling on the road, and an isochronous control (A) that maintains the engine speed by changing the output with respect to the resistance during tillage work. ) Mode and automatically selectable with information from GPS (41) ,
The engine is provided with a common rail (11), and the common rail (11) is provided with means for calculating the rail pressure (P) from the engine speed (N) and the output torque (T).
When the engine is started, the droop control (B) mode or isochronous control (A) mode is selected based on information from the GPS (41), and the rail pressure (P) is set based on the control mode.
The temperature of the intake air to the engine is measured and the voltage of the battery is measured. When the temperature of the intake air is less than a set temperature or when the battery voltage is less than the set voltage value, the rail pressure (P) Change rising,
A tractor comprising an engine control unit (17) for performing control for injecting fuel from an injector (10) to start an engine when the rail pressure (P) becomes equal to or higher than a set rail pressure.

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