JP4600441B2 - Engine starter - Google Patents

Description

  The present invention relates to an engine starting device.

  In recent years, as a fuel supply system for diesel engines, the pressure of fuel is increased by a high-pressure fuel pump (supply pump), and the injection amount and timing of fuel are controlled by an electric injector. The common rail system called the expression is widely adopted. In this common rail type diesel engine, fuel is stored in a strong metal pipe (common rail) to be high pressure, and then the high pressure fuel is injected from each injector. Therefore, a common rail type diesel engine does not require complicated valve mechanism control, injection control, or the like on the supply pump side. Further, in the common rail system, since the injector is responsible only for the valve opening operation, it can be brought close to ideal fuel injection for complete combustion of fuel such as multistage injection (pilot injection). An example of such a common rail type diesel engine is disclosed in Patent Document 1 below.

Here, an example of the configuration of a conventional general common rail diesel engine and its peripheral devices will be described with reference to FIG.
FIG. 4 is a schematic diagram showing a configuration example of a conventional common rail diesel engine and its peripheral devices. As shown in FIG. 4A, a conventional common rail diesel engine 30 includes a starter 31 that is a motor, a supply pump 33 that is a high-pressure pump for fuel pressurization, and a crankshaft 44 (see FIG. 4B). Other gears 32 such as a flywheel 45 attached to the vehicle, a battery 34 for supplying power to the starter 31, an ECU 35 for controlling the engine 30 and the like are provided.

  As shown in FIG. 4B, a starter pinion gear (starter pinion) 41 is attached to the output rotation shaft 40 of the starter 31. A supply pump pinion gear (supply pump pinion) 43 is attached to the input rotary shaft 42 of the supply pump 33. The flywheel 45 and the supply pump pinion 43 are always connected.

JP-A-6-173834

  In the above-described conventional common rail type diesel engine, if an electric pump driven by a motor is not separately installed in the fuel tank, air biting may occur at the time of fuel pumping after a fuel shortage, or fuel pumping In the initial stage, it is difficult to pump the fuel from the fuel tank to the supply pump 33 in a short time due to the fact that air is sucked in, and it takes time to supply the fuel to the injector.

Such a phenomenon will be described in more detail with reference to FIG.
FIG. 5 is a diagram showing changes in the rail pressure when the conventional common rail type diesel engine is normal and the rail pressure when the air is bitten. As shown in FIG. 5, when the diesel engine 30 that is set to be equal to or higher than the initial explosive rail pressure capable of causing the fuel to explode when the air is bitten, reaches a rail pressure (hereinafter referred to as a target rail pressure) at which the diesel engine 30 can be started. Since it takes time and the supply pump 33 is driven powerfully to pump fuel further, the rail pressure may overshoot after reaching the target rail pressure.

  Alternatively, in order to make the pressure inside the common rail (rail pressure) reach the pressure at which the initial explosion is possible, ideally only the supply pump 33 needs to be driven, but in the structure of a conventional common rail type diesel engine, Since only the supply pump 33 cannot be driven, the entire engine 30 is driven simultaneously. For this reason, the battery 34 is wasted.

  When the rail pressure reaches the target rail pressure, the electromotive force of the battery 34 has already decreased, and the power of the starter 31 that drives the engine 30 is sufficient even though the rail pressure has reached the target rail pressure. Therefore, it takes time to reach the rotation speed when the engine 30 is completely started (hereinafter, the complete explosion rotation speed). Furthermore, there is a risk that the explosion speed will not be reached at extremely low temperatures.

  In view of the above, the present invention provides an engine starter that can start an engine in a short time even when air-engaged or the like in a common rail diesel engine without an electric pump installed. Objective.

In order to solve the above-described problems, the present invention provides an engine starter, a supply pump that pressurizes fuel supplied to the engine, and a common rail that distributes fuel pressurized by the supply pump to each cylinder of the engine. A rail pressure detecting means for detecting a rail pressure that is an internal pressure of the common rail, a rotational speed detecting means for detecting the rotational speed of the engine, and the starter and the supply pump. A connected state in which driving force is transmitted from the starter to the supply pump or a non-connected state in which driving force is not transmitted from the starter to the supply pump according to the detection values of the pressure detecting means and the rotation speed detecting means. And a first drive transmission means.
According to the present invention, since the supply pump can be driven efficiently according to the rail pressure and the engine speed, the time required for starting the engine can be shortened. Furthermore, since the time required for starting the engine can be shortened, the starter can be protected.

In the present invention, a driving force is interposed between the supply pump and the driving gear of the engine, and a driving force is applied from the supply pump to the driving gear according to the detection values of the rail pressure detection means and the rotation speed detection means. It is preferable to further include a second drive transmission means for making a connection state to be transmitted or a non-connection state in which a driving force is not transmitted from the supply pump to the drive gear.
In this case, since only the supply pump can be directly driven by the starter, the load on the battery can be reduced and the battery can be used efficiently.

In the present invention, it further comprises rail pressure setting means for presetting a startable rail pressure which is a rail pressure at which the engine can be started, and the first drive transmission means has the rail pressure detected by the rail pressure detection means. It is preferable that the starter and the supply pump are connected until the startable rail pressure is reached.
In this case, since the supply pump can be driven more efficiently, the time required for starting the engine can be further shortened.

In the present invention, the second drive transmission means preferably connects the supply pump and the drive gear when the rail pressure detected by the rail pressure detection means reaches the target rail pressure. .
In this case, since the fuel supplied into the cylinder of the engine can be surely exploded, the startability of the engine can be improved. For this reason, fuel consumption can be reduced.

The present invention further includes a rotation speed setting means for presetting the complete explosion speed of the engine, wherein the first drive transmission means has the rotation speed detected by the rotation speed detection means reaching the complete explosion rotation speed. In this case, it is preferable that the starter and the supply pump are disconnected.
In this case, the starter can be protected because the supply pump can be driven only by the engine that has been started.

In the present invention, it is preferable that the second drive transmission means disconnects the supply pump and the crankshaft when the engine is stopped.
In this case, since only the supply pump can be efficiently driven at all times when the engine is started, the engine start time can be shortened.

  According to the present invention, in a common rail type diesel engine in which no electric pump is installed, the engine can be started in a short time even when the air is bitten.

  Hereinafter, an embodiment of an engine starter according to the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic diagram illustrating a configuration example of an engine and its peripheral devices according to the present embodiment. The engine according to this embodiment is a common rail diesel engine. As shown in FIG. 1A, around the engine 10, there are a starter 11 that is a motor that starts the engine 10, a supply pump 12 that is a high-pressure pump that pressurizes fuel, and a crankshaft 25 of the engine 10 (see FIG. Other gears 13 (driving gears) such as a flywheel 26 attached to (b)), a battery 14 for supplying electric power to a starter and the like, an ECU 15 for controlling the engine and the like are installed.

  The battery 14 also supplies electric power to the ECU 15 and the spark plug of the engine 10. Further, the engine 10 includes a rail pressure detection sensor 16 (rail pressure detection means) for detecting the pressure inside the common rail and a rotation speed detection sensor 17 (rotation speed detection means) for detecting the rotation speed of the engine 10. is set up. Values detected by the rail pressure detection sensor 16 and the rotation speed detection sensor 17 are transmitted to the ECU 15. In this embodiment, the rail pressure and the engine speed are directly detected by installing the rail pressure detection sensor 16 and the rotation speed detection sensor 17, but other than this, for example, by other existing sensors. The ECU 15 may estimate or calculate / calculate from the sensing result.

  As shown in FIG. 1B, a starter pinion gear (starter pinion) 21 is attached to the output shaft 20 that outputs the driving force of the starter 11. A supply pump pinion gear (supply pump pinion) 23 is attached to the input shaft 22 that drives the fuel pressurizing mechanism inside the supply pump 12.

  Further, a first drive transmission pinion gear (first pinion) 24 that is interposed between the starter pinion 21 and the supply pump pinion 23 and transmits a driving force is installed between the starter pinion 21 and the supply pump pinion 23. Has been. The first pinion 24 is connected to the starter pinion 21 and the supply pump pinion 23 in a connected state where the driving force is transmitted or in a disconnected state where the driving force is not transmitted. The transmission means) 18 is operable. Here, it is assumed that the first drive transmission mechanism 18 is in an ON state and the non-connected state is a state in which the first drive transmission mechanism 18 is OFF.

  In addition, a second drive transmission pinion gear (second pinion) 27 that is interposed between the supply pump pinion 23 and the flywheel 26 and transmits a driving force is installed between the supply pump pinion 23 and the flywheel 26. Has been. The second pinion 27 is connected to the supply pump pinion 23 and the flywheel 26 in a connected state where the driving force is transmitted or in a disconnected state where the driving force is not transmitted. The transmission means) 19 is operable. Here, it is assumed that the connected state is the state where the second drive transmission mechanism 19 is ON, and the disconnected state is the state where the second drive transmission mechanism 19 is OFF.

  In the present embodiment, the second pinion 27 is configured to drive the flywheel 26, but other than this, for example, a gear provided directly on the crankshaft 25 by the second pinion 27 or a crankshaft 25 is installed. It is also possible to adopt a configuration for driving other gears 13.

  The engine starter according to the present embodiment can efficiently drive the supply pump 12 in accordance with the rail pressure and the engine speed due to the structure described above. Thereby, the time required for starting the engine 10 can be shortened. In addition, since the time required for starting the engine 10 can be shortened, the starter 11 can be protected. Furthermore, the load on the battery 14 can be reduced, and the battery 14 can be used efficiently.

  Next, the control procedure of the engine starter according to this embodiment will be described. FIG. 2 is a flowchart showing a control procedure at the time of engine start of the engine starter according to the present embodiment. Hereinafter, the contents of processing performed in each step will be described in order for each step with reference to FIG.

First, in step s10, the ECU 15 starts driving the starter 11 in response to detection of a start signal of the engine 10 generated when the engine 10 is started. After execution of step s10, step s11 is executed.
In step s11, the ECU 15 turns on the first drive transmission mechanism 18 to operate the first pinion 24 to connect the starter pinion 21 and the supply pump pinion 23 to each other. After execution of step s11, step s12 is executed.

  In step s12, the ECU 15 transmits the driving force from the starter 11 by the first pinion 24, and rotates the input shaft 22 to which the supply pump pinion 23 is attached to drive the supply pump 12. In this embodiment, at this time, the supply pump pinion 23 and the flywheel 26 are in a disconnected state by control when the engine 10 is stopped, which will be described later. For this reason, the starter 11 is in a state in which only the supply pump 12 can be driven. After execution of step s12, step s13 is executed.

  In step s13, the ECU 15 determines whether the rail pressure detected by the rail pressure detection sensor 16 has reached a rail pressure at which the engine 10 can be started (hereinafter referred to as a target rail pressure). The target rail pressure is set to be higher than the rail pressure at which the fuel supplied into the cylinder of the engine 10 can be exploded and stored in the ECU 15 in advance. Thus, in the present embodiment, the ECU 15 also functions as a rail pressure setting unit. If the rail pressure has reached the target rail pressure, step s14 is executed. If the rail pressure has not reached the target rail pressure, step s11 is executed again. Thereby, since the fuel supplied into the cylinder of the engine 10 can be reliably exploded, the startability of the engine 10 can be improved. For this reason, fuel consumption can be reduced.

  In the present embodiment, the ECU 15 determines whether or not the rail pressure has reached the target rail pressure. More preferably, for example, the rail pressure has reached the target rail pressure, and the state where the rail pressure has been stable for a certain period of time is maintained. It is also possible to make it possible to start the engine 10 more reliably by determining whether it has continued.

  In step s14, the ECU 15 turns on the second drive transmission mechanism 19 to operate the second pinion 27 to bring the supply pump pinion 23 and the flywheel 26 into a connected state. In the present embodiment, the second pinion 27 uses a vacuum pump gear that is an existing movable pinion gear. After execution of step s14, step s15 is executed.

  In step s15, the ECU 15 determines whether the engine speed detected by the engine speed detection sensor 17 has reached the complete explosion speed. The complete explosion rotation speed is set in advance in the ECU 15 as the rotation speed when the engine 10 is completely started. Thus, in the present embodiment, the ECU 15 also functions as a rotation speed setting unit. If the engine speed has reached the complete explosion speed, step s16 is executed. If the engine speed has not reached the complete explosion speed, step s14 is executed again.

  In step s16, the ECU 15 turns off the first drive transmission mechanism 18 to operate the first pinion 24, thereby bringing the starter pinion 21 and the supply pump pinion 23 into a disconnected state. The first pinion 24 is a freewheel hub, a one-way clutch, or the like, so that the starter pinion 21 and the supply pump pinion 23 are automatically disconnected when the engine speed reaches the complete explosion speed. It is also possible to do so. After execution of step s16, the control at the time of engine start is ended. Thus, since the supply pump 12 can be driven only by the engine 10 that has been started, the starter 11 can be protected.

  FIG. 3 is a flowchart showing a control procedure when the engine is stopped in the engine starter according to this embodiment. Hereinafter, the contents of processing performed in each step will be described in order for each step with reference to FIG.

In step s20, the ECU 15 determines whether a stop signal issued when the engine 10 is stopped is detected. When the stop signal of the engine 10 is detected, step s21 is executed. Moreover, when the stop signal of the engine 10 is not detected, the control at the time of engine stop is complete | finished.
In step s21, the ECU 15 turns off the second drive transmission mechanism 19, operates the second pinion 27, and disconnects the supply pump pinion 23 and the flywheel 26 from each other. After execution of step s21, the control when the engine is stopped is terminated. As a result, only the supply pump 12 can be efficiently driven at all times when the engine 10 is started, so that the start time of the engine 10 can be shortened.

  As described above, according to the engine starter according to the present embodiment, only the supply pump 12 can be driven when the engine 10 is started, so that the time until the rail pressure reaches the target rail pressure is shortened. Can do. For this reason, the starting time of the engine 10 can be shortened.

  The engine starter according to the present invention can be applied to, for example, a common rail type diesel engine in which no electric pump is installed.

The schematic diagram which showed the structural example of the engine which concerns on one Embodiment of this invention, and its peripheral device. The flowchart which showed the procedure of the control at the time of engine starting of the engine starting apparatus which concerns on one Embodiment of this invention The flowchart which showed the procedure of the control at the time of the engine stop of the engine starting apparatus which concerns on one Embodiment of this invention. Schematic diagram showing a configuration example of a conventional common rail diesel engine and its peripheral devices The figure which showed the change of the rail pressure at the time of normal and the rail pressure at the time of air biting of the conventional common rail type diesel engine

Explanation of symbols

10 Engine 11 Starter 12 Supply pump 13 Other gear 14 Battery 15 ECU
16 rail pressure detection sensor 17 rotation speed detection sensor 18 first drive transmission mechanism 19 second drive transmission mechanism 20 starter output shaft 21 starter pinion 22 supply pump input shaft 23 supply pump pinion 24 first pinion 25 crankshaft 26 flywheel 27 first 2 pinions

Claims (5)

An engine starter,
A supply pump for pressurizing fuel supplied to the engine;
A common rail that distributes fuel pressurized by the supply pump to each cylinder of the engine;
Rail pressure detecting means for detecting a rail pressure that is an internal pressure of the common rail;
A rotational speed detection means for detecting the rotational speed of the engine;
A connection state interposed between the starter and the supply pump, in which a driving force is transmitted from the starter to the supply pump in accordance with detection values of the rail pressure detection means and the rotation speed detection means, or the starter A first drive transmission means configured to be in a non-connected state in which drive force is not transmitted from the power supply pump to the supply pump ;
An engine starter comprising: rail pressure setting means for presetting a startable rail pressure that is a rail pressure at which the engine can be started. A connection state that is interposed between the supply pump and the drive gear of the engine, and in which the drive force is transmitted from the supply pump to the drive gear according to the detection values of the rail pressure detection means and the rotation speed detection means 2. The engine starter according to claim 1, further comprising a second drive transmission unit configured to be in a disconnected state in which a drive force is not transmitted from the supply pump to the drive gear. The second drive transmission means, the rail when the rail pressure detected by pressure detecting means has reached the target rail pressure, claim 2, characterized in that the said supply pump said driving gear in a connected state engine start-up device according to. A rotation speed setting means for presetting the complete explosion speed of the engine;
The first drive transmission means disconnects the starter and the supply pump when the rotational speed detected by the rotational speed detection means reaches the complete explosion rotational speed. 1-3 . Engine starter given in any 1 paragraph. The engine start device according to any one of claims 2 to 4, wherein the second drive transmission means disconnects the supply pump and the crankshaft when the engine is stopped. .

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