JP2001050132A - High pressure injector for high pressure fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably perform fuel injection by stabilizing an operation of a high pressure injector even at the time of a cold starting. SOLUTION: In a high pressure injector for a high pressure fuel injection device for pressing a pressure intensifying piston by delivering operating oil O to a pressing chamber by opening a poppet valve 23, pressurizing fuel of a pressure intensifying chamber by the pressure intensifying piston and injecting pressurized fuel via a needle valve, the injector is constituted by being provided with a heating means 28 heating operating oil O accumulated within an armature chamber 27 faced by an armature 22 of a solenoid part 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure injector used for a high-pressure fuel injection device for an internal combustion engine for a vehicle or the like. More specifically, the present invention relates to a high-pressure injector that drives a pressure-intensifying piston with high-pressure operating oil to increase fuel pressure and inject fuel.

[0002]

2. Description of the Related Art A high-pressure fuel injection system using a hydraulic injector in a multi-cylinder internal combustion engine includes a fuel injection system (common rail injection system) and a pressure accumulation type injection system (accumulator injection system).

[0003] This fuel injection system is a system in which the injection amount, the injection timing, and the like are controlled by an electronic circuit. In the pressure accumulation type injection system, fuel is distributed from the injection pump to each combustion chamber via a common passage and a pressure accumulation chamber. It is a method to do.

An electronically controlled hydraulically driven high-pressure fuel injection system, which is one of the fuel injection systems, comprises an electronic control system 50, a hydraulic system 60, and a fuel system 70 as shown in FIG. .

[0005] The electronic control system of the high-pressure fuel injection device
50 is the engine speed sensor Ne and the accelerator opening Ac
The controller (ECM: Electric Control Module) 51 receives various detection signals such as c, engine coolant temperature Tc, etc., calculates the optimal fuel injection amount and injection timing, and controls the hydraulic system 60 and the fuel system 70. Then, the fuel is controlled so as to be injected at an optimum injection amount and injection timing.

The hydraulic system 60 includes a fuel system 70
This is a system for supplying operating oil O for operating the high-pressure injectors (fuel injection nozzles) 10 and 10A of the oil pump. The operating oil O of an oil pan 64 is sucked up by an engine oil pump 65, passed through an oil filter 66, and then passed through a high-pressure oil pump. High pressure hydraulic oil is accumulated in an oil rail (high pressure oil manifold) 62 while adjusting oil pressure with an oil rail hydraulic control valve 63 by 61.

In the fuel system 70, the fuel F in the fuel tank 72 is sucked up by the fuel pump 74, supplied to the high-pressure injectors 10, 10A and injected, and the fuel F not injected into the combustion chamber is returned to the fuel tank 72. Has a role.

As shown in FIG. 7, a prior art high-pressure injector 10A used in this electronically controlled hydraulically driven fuel injection device includes a solenoid portion 20A, a hydraulic passage portion 30, and a fuel passage portion 40 in order from the top. It is configured.

Then, the fuel injection command is sent to the controller 51.
, The solenoid unit 20A drives the solenoid 21 to open the poppet valve 23, and the high-pressure hydraulic oil O
The high-pressure hydraulic oil O operates a fuel pump composed of a pressure-intensifying piston 34, a plunger 35, and a pressure-increasing chamber 44. Then, the fuel F in the pressure increasing chamber 44 is pressurized, and the needle valve 47 is lifted by this pressurization, and the fuel F is supplied from the nozzle hole 15a.
Is injected into the combustion chamber.

When the current to the solenoid 21 is cut off in response to a fuel injection stop command, the poppet valve 23 is lowered and closed by the urging force of the poppet spring 24, and the high-pressure oil passage 32 to the pressure-intensifying piston 34 is closed. The inlet side hydraulic passage 31 is shut off.

As a result of this interruption, the pressure-intensifying piston 34 returns with the urging force of the return spring 36, the pressure of the fuel F decreases, and the needle valve 47 closes the nozzle hole 15a with the urging force of the nozzle spring 46. Injection stops.

[0012]

However, in the conventional high-pressure injector 10A having the above structure,
If the fuel is injected when the oil temperature of the working oil O is −10 ° C. or less during a cold start or the like, the fuel injection of the injector 10A is performed because the temperature of the working oil O is low and the viscosity of the working oil O is high. There is a problem that the amount becomes unstable and the rotation of the engine becomes unstable.

That is, in the case of an electronically controlled hydraulic drive type fuel injection device, as shown in FIG.
Armature chamber 27 leaking from the gap between
The hydraulic oil O in the armature chamber 27 moves through the gap between the poppet sleeve 25 and the poppet valve 23 with the movement of the armature 22.

Therefore, when the moving speed of the operating oil O is high, the armature chamber 27 is filled with the operating oil O quickly, so that the movement of the armature 22 becomes smooth and fast, and the fuel F is injected as instructed by the controller 51. However, conversely, when the oil temperature becomes low and the viscosity becomes high, and the moving speed of the working oil O becomes slow, the filling of the armature chamber 27 with the working oil O becomes slow, so that the movement of the armature 22 becomes slow,
The time during which the poppet valve 23 is lifted becomes shorter,
That is, the injection amount of the fuel F decreases.

In particular, since the viscosity of the working oil O in the armature chamber 27 becomes higher when the oil temperature becomes lower than -10 ° C., the movement of the armature 22 is not performed smoothly, and the injection amount of the fuel F decreases. .

Moreover, the amount of decrease in the fuel F injection amount is as follows:
It changes depending on the leakage amount of the hydraulic oil O, and the leakage amount is
Since the injector 10A provided in each cylinder differs, the injection amount of the fuel F in each cylinder changes, and as a result, the rotation of the engine becomes unstable.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a high-pressure injector of a high-pressure fuel injection device, in which, during a cold start, an armature chamber of the high-pressure injector is warmed up by a heater. Another object of the present invention is to provide a high-pressure injector for a high-pressure fuel injection device, which can stabilize the operation of a high-pressure injector even during a cold start by raising the oil temperature of a working oil and stably perform fuel injection.

[0018]

The high-pressure injector of the high-pressure fuel injection device for achieving the above object is constituted as follows. 1) A solenoid portion having a solenoid for opening and closing the poppet valve, a hydraulic passage portion having a high-pressure oil passage for sending high-pressure hydraulic oil from the outside to the pressing chamber, and supplying fuel to the needle valve via the pressure-intensifying chamber. A fuel passage portion having a fuel passage for supplying the operating oil to the pressing chamber by opening the poppet valve to press the pressure-intensifying piston, and pressurize the fuel in the pressure-increasing chamber by the pressure-increasing piston. A high-pressure injector of a high-pressure fuel injection device that pressurizes and injects the pressurized fuel through the needle valve, wherein the high-pressure injector includes heating means for heating the working oil accumulated in an armature chamber facing an armature of the solenoid unit. It is composed.

According to this configuration, by providing the heating means and raising the temperature of the working oil accumulated in the armature chamber, the viscosity of the working oil is reduced, and the movement of the armature is smoothed. The movement interruption of the armature caused by the hydraulic oil is eliminated, and the fuel injection is stabilized. 2) The heating means is formed by providing a spacer provided between the cap body and the solenoid portion with a heater function.

That is, in the high-pressure injector of the high-pressure injection device, the spacer is formed by a heater such as a ceramic heater so that the temperature of the armature chamber can be increased at the time of cold start. 3) The heating means heats only for a predetermined heating time determined based on the oil temperature only when the engine is started and when the oil temperature of the working oil is lower than a predetermined lower limit. Constitute.

With this configuration, the time for heating the working oil can be managed in accordance with the oil temperature, and the heater function can be controlled, so that the durability of the heater function can be enhanced.

Further, the heating time (required energization time) only needs to increase the oil temperature in the armature chamber to a certain degree of viscosity, so that the relationship between the heating time and the oil temperature of the working oil at the beginning of heating is shown in FIG. As shown in one example, the relationship is inversely proportional, but the coefficient of this inverse proportion, that is, the slope in FIG. 5 differs depending on the engine.

If the oil temperature is high and the viscosity is low, there is no need for heating. Usually, if the oil temperature is 10 ° C. or higher, there is no need for initial heating.

Since the heating time of the heater is controlled to the minimum necessary according to the oil temperature, the power consumption is reduced and the durability of the heater is improved.

In particular, when an electric heater is used as the heating means, the resistance of the electric heater rises when the temperature is high, so that the temperature rises rapidly under the condition of a constant voltage. For this reason, the heater energization time is controlled by the oil temperature, the energization is lengthened when the oil temperature is low, and the energization is not performed when the temperature is close to room temperature of 10 ° C or higher. It is important to prevent this and extend the life of the heater. 4) Further, when the high-pressure fuel injection device is an electronically controlled hydraulic drive type fuel injection device, a further effect can be exhibited.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-pressure injector of a high-pressure fuel injection device according to an embodiment of the present invention will be described below with reference to the drawings. [Electronically controlled hydraulically driven high-pressure fuel injection device] First, a high-pressure fuel injection device using a high-pressure injector according to an embodiment of the present invention will be described.

The high-pressure injector used in the embodiment of the present invention is an electronically controlled hydraulically driven high-pressure fuel injection system composed of an electronic control system 50, a hydraulic system 60, and a fuel system 70 as shown in FIG. Used in equipment.

Electronic control system for this high-pressure fuel injection device
A controller 50 controls various signals such as an engine speed sensor Ne, an accelerator opening Acc, and an engine coolant temperature Tc from an engine speed sensor 52, an accelerator position sensor 53, an engine coolant temperature sensor 54, and the like.・ Control module) 51, calculates the optimal fuel injection amount and injection timing from these input signals, controls the hydraulic system 60 and the fuel system 70, and optimizes the fuel injection over the entire operating range of the engine. It is controlled so that it is injected with the quantity and the injection timing.

The hydraulic system 60 includes a high-pressure oil pump 61, an oil rail (high-pressure oil manifold) 62, an oil-rail hydraulic control valve 63, and the like, and operates the high-pressure injector (fuel injection nozzle) 10 of the fuel system 70. This is a system for supplying the working oil O. The working oil O of the oil pan 64 is sucked up by the engine oil pump 65 and passed through the oil filter 66, so that the high-pressure oil pump 61 accumulates the high-pressure working oil O on the oil rail 62. At this time, the oil pressure is adjusted by controlling the oil rail oil pressure control valve 63 according to the command signal of the controller 51.

The fuel injection system 70 includes a fuel tank
The 72 fuel F is passed through the fuel filter 73 by the fuel pump 74, sucked up, and supplied to the high-pressure injector 10.
Fuel F not injected into the combustion chamber by high-pressure injector 10
Returns to the fuel tank 72 through the orifice 75. [Configuration of High-Pressure Injector] As shown in FIG. 1, a high-pressure injector 10 according to an embodiment of the present invention includes a solenoid section 20, a hydraulic passage section 30, and a fuel passage section in this order from the top.
It consists of forty and forty.

The solenoid section 20 includes a cap body 12
And a solenoid 21 arranged above the high-pressure injector body 11 and operated by an engine controller (ECM: electric control module) 51, and an armature 22 attracted when the solenoid 21 is energized.
And a poppet valve 23 connected to the armature 22 to open and close between the hydraulic passages 31 and 32 of the hydraulic passage portion 30 and a poppet spring 24 for urging the poppet valve 23 in the valve closing direction. You.

Next, the hydraulic passage section 30 includes an inlet-side hydraulic passage 31 and a high-pressure oil passage 32 inside the high-pressure injector body 11.
, The hollow portion 33, the passage of the arcuate concave portion 33a and the drain passage 37.
The inlet-side hydraulic passage 31 communicates with an oil rail 62 that stores the working oil O pressurized by a high-pressure oil pump 61, and the high-pressure oil passage 32 passes through a poppet valve 23 through a poppet valve 23. Is configured to reach the pressing chamber 38 of the pressure-intensifying piston 34 arranged on the extension of the above.

The hollow portion 33 accommodates the poppet valve 23 and the poppet spring 24, and
When the valve is closed, it communicates with the drain passage 37 through the opening of the poppet sleeve 39, and the passage of the arcuate concave portion 33a communicates the operating oil O after fuel injection into the hollow portion 33 through the high-pressure oil passage 30, Further, the drain passage 37 is configured to discharge the hydraulic oil O to the oil pan 64.

Then, the poppet valve 23 is operated in accordance with ON / OFF of the solenoid 21 to communicate or close between the inlet side hydraulic passage 31 and the high pressure oil passage 32. At the time of the communication, the high pressure oil O is transferred to the pressing chamber 38. Inlet booster piston
34, and drives the plunger 35 interlocked with the pressure-increasing piston 34 against the urging force of the return spring 36,
The pressure of the fuel F in the pressure increasing chamber 44 of the fuel passage 40 is increased.

The fuel passage portion 40 is formed inside the case 13 and guides the fuel F supplied from the fuel pump 74 from the fuel inlet portion 41 to the nozzle hole 15 a of the nozzle tip 15. Check valve 43, booster chamber 44, high-pressure fuel passage 45
And the like. A needle valve (needle valve) for opening and closing the nozzle hole 48a is provided in the nozzle body 14.
The nozzle spring 47 is disposed so as to be urged by the nozzle spring 46 in the direction of closing the nozzle hole 15a.

The fuel F passing through the high-pressure fuel passage 45
On the other hand, the fuel F is increased in the pressure increasing chamber 44 by the movement of the pressure increasing piston 34 and the plunger 35, and the needle valve 47 is moved against the nozzle spring 46 by the increased pressure of the fuel F, The high-pressure fuel F is configured to be injected from the nozzle hole 15a. [Heater for hydraulic oil] High-pressure injector as described above
In the present invention, a special contrivance is provided for the armature chamber 27 in the present invention.

That is, as shown in FIG. 3, the spacer 28 surrounding the armature chamber 27 shown in FIGS. 1 and 2 is formed as a ceramic heater 28 provided with a nichrome wire 28b in a ceramic 28a. That is, the spacer 28 between the solenoid portion 20 and the cap body 12 has a heater function,
The structure is such that the temperature of the working oil O accumulated in the armature chamber 27 can be raised.

Further, from the viewpoint of power consumption and durability, the heating time is controlled by the oil temperature at the time of starting, and the heater function is controlled by, for example,
Control is performed according to the floater chart shown in FIG. [Operation] Next, the high-pressure injector 10 having the above-described configuration will be described.
The operation of will be described. [Heating of Ceramic Heater] When the operation of the engine is started, an initial heating control program of a control flow as shown in FIG. 4 relating to the initial heating of the ceramic heater 28 of the high-pressure injector 10 is called, and the energization time Stime of the heater 28 is calculated.

When the initial heating control flow shown in FIG. 4 is appropriately called from the main engine operation flow and started, in step S10, the engine oil temperature (the operating oil O
Temperature) Toil and the engine speed Ne are input.

Then, in S12, it is determined whether or not the engine is cold starting, that is, whether or not the oil temperature Toil is lower than 10 ° C. and whether or not the engine speed Ne is zero. If it is determined, in step S12, the energizing time Stime is calculated from the map data M (Toil) indicating the relationship between the oil temperature Toil and the energizing time Stime as shown in FIG. If so, step S1
At 3, the energizing time Stime is set to zero. Then, in step S14, the current supply time Stime is output, and the process returns.

On the other hand, the control means 51 of the injector 10 that has received the power-on time Stime energizes the nichrome wire 28a of the ceramic heater 28 for a predetermined power-on time (heating time) Stime to heat the armature chamber 27. The oil temperature of the working oil O in the armature chamber 27 is increased, thereby lowering the viscosity of the working oil O, and the working oil O moving to the armature chamber 27 via the gap between the poppet sleeve 25 and the poppet valve 23 is reduced. The movement is smoothed, whereby the movement of the armature 22 is smoothed, and the injection of the fuel F is stabilized. [Fuel Injection] The injection of the fuel F is performed as follows.

Engine speed Ne, accelerator opening Acc
A controller (ECM) 51 which detects the operating state of the engine based on an input signal such as the engine coolant temperature Tc and the like, energizes the solenoid 21 of the high-pressure injector 10 with a fuel injection amount and timing optimal for the operating state.

When the solenoid 21 is energized, the armature 22 is pulled up, the poppet velve 23 connected to the armature 22 is opened against the poppet spring 24, and the high-pressure operating oil O is supplied to the hydraulic passage 30. It flows into the high-pressure oil passage 32 from the inlet-side hydraulic passage 31.

Due to the inflow of the high-pressure hydraulic oil O, the pressure-intensifying piston 34 is pushed down, and the pressure of the fuel F in the pressure-intensifying chamber 44 is increased by the plunger 35 pushed down by the pressure-increasing piston 34. At this time, the pressure of the fuel F to be increased is higher than the pressure of the high-pressure hydraulic oil O by the pressure increasing piston.
The pressure is increased by the area ratio between the upper area of the cylinder 34 and the lower area of the plunger 35. This area ratio is usually formed about 7 times, and the fuel F is increased to about 7 times the high pressure working oil O (about 40 to 200 kg / cm ² ).

Then, this increased pressure fuel F (about 280
１1400 kg / cm ² ), the needle valve 47 at the tip of the high-pressure injector 10 is lifted and the fuel F is discharged from the nozzle hole 15a.
Inject.

When the energization from the controller 51 is completed, the poppet valve 23 is closed by the urging force of the poppet spring 24, the high-pressure hydraulic oil O is shut off, and the fuel F
Is the booster piston 34 and the plunger 35 is the return spring
Return by the urging force of 36, the pressure drops, so the nozzle hole
15a is closed by the needle valve 47 returned by the urging force of the nozzle spring 46, and the injection of the fuel F is stopped.

At the end of the energization, as shown in FIG. 9, as the poppet valve 23 descends, the upper cutout 23a of the poppet valve 23 and the opening of the poppet sleeve 25 communicate with each other. Is discharged to the drain passage 37. [Effect] According to the high-pressure injector 10 of the high-pressure fuel injection device having the above configuration, the spacer 28 between the solenoid valve 20 and the cap body 12 is formed as a ceramic heater, and the armature chamber 27 is operated by heating during the cold start. With a structure that can raise the oil temperature of the oil O, the temperature of the working oil accumulated in the armature chamber 27 can be raised even during a cold start to reduce the viscosity and smooth the movement of the armature 22. In addition, the fuel F injection can be stabilized.

Further, the energizing time of the ceramic heater 28 is
Since it is determined in relation to the oil temperature in the armature chamber 27, the power consumption can be reduced, and the heating of the working oil O can be prevented.
The durability of 28 is not lost.

The relationship between the oil temperature Toil of the engine oil and the required energizing time Stime is inversely proportional to each other as shown in FIG. 5, and this oil temperature Toil and the necessary energizing time Stime for this oil temperature Toil are shown. Although it depends on the engine, the working oil O of the high-pressure injector 10 can be heated according to the relationship between the oil temperature Toil input in advance and the required energization time Stime, and excessive heating can be prevented.

[0050]

As described above, according to the high-pressure injector of the high-pressure fuel injection device according to the present invention, since the heating means for heating the operating oil accumulated in the armature chamber is provided, the viscosity of the operating oil is high and the fuel is high. At the time of a cold start in which the injection is likely to be unstable, the working oil accumulated in the armature chamber can be initially heated to raise the oil temperature of the working oil and lower the viscosity.

Therefore, the movement of the armature caused by the low-temperature, high-viscosity working oil can be eliminated, the operation of the armature can be made smooth, and the fuel injection can be performed stably.

Further, by providing the spacer provided between the cap body and the solenoid portion with a heater function, the heating means can be used without changing the design of the high-pressure injector other than the spacer portion. Can be prepared.

Further, the heating means is configured to heat the engine only during a predetermined heating time determined based on the oil temperature only when the oil temperature of the working oil is lower than a predetermined lower limit value when the engine is started. By doing so, the time for heating the operating oil can be controlled by the oil temperature, and the time used for heating can be minimized to a minimum, so that the power consumption of the heater is reduced and the durability of the heater is also advantageous. Become.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an entire high-pressure injector according to the present invention.

FIG. 2 is a side sectional view of an upper portion of a high-pressure injector main body showing a state of disposing a ceramic heater according to the present invention.

FIG. 3 is a perspective view including a cross section showing a structure of a ceramic heater according to the present invention.

FIG. 4 is a diagram showing a control flow of initial heating of a ceramic heater according to the present invention.

FIG. 5 is a diagram showing the relationship between the operating oil temperature and the operating temperature according to the present invention.

FIG. 6 is a configuration diagram showing each system of the fuel injection device according to the present invention.

FIG. 7 is a side sectional view of a prior art high pressure injector.

FIG. 8 is a cross-sectional side view of the top of a prior art high pressure injector.

FIG. 9 is a partially enlarged side sectional view of an upper portion of a high-pressure injector showing a hollow portion according to the related art.

[Explanation of symbols]

 10 High pressure injector 12 Cap body 20 Solenoid section 21 Solenoid 22 Armature 23 Poppet valve 27 Armature chamber 28 Spacer (heater: heating means) 30 Hydraulic passage section 32 High pressure oil passage 34 Booster piston 38 Pressing chamber 40 Fuel passage section 44 Booster chamber 47 Needle valve F Fuel O Hydraulic oil Toil Oil temperature Stime Heating time

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G066 AA07 AB02 AC08 AD12 BA00 BA21 BA46 CA01T CA04T CA08 CA09 CA31 CA32U CC06T CC14 CC26 CD22 CD25 CD26 CD29 CE12 CE13 CE24 CE25 DB01 DC04 DC09 DC13 DC14

Claims (4)

[Claims] 1. A solenoid section having a solenoid for controlling the opening and closing of a poppet valve, a hydraulic path section having a high-pressure oil passage for sending high-pressure hydraulic oil from the outside to a pressing chamber, and a needle for passing fuel through a pressure-increasing chamber. A fuel passage portion having a fuel passage for supplying the fuel to the valve. The operating oil is sent to the pressing chamber by opening the poppet valve to press the pressure-intensifying piston. A high-pressure injector of a high-pressure fuel injection device that pressurizes fuel and injects the pressurized fuel through the needle valve, wherein the heating heats the working oil accumulated in an armature chamber facing an armature of the solenoid unit. Means for a high-pressure fuel injection device. 2. The high-pressure fuel injection device according to claim 1, wherein the heating means is formed by providing a heater function to a spacer disposed between the cap body and the solenoid portion. High pressure injector. 3. The method according to claim 1, wherein the heating unit is configured to start the engine when the engine is started.
The high-pressure fuel according to claim 1 or 2, wherein heating is performed only for a predetermined heating time determined based on the oil temperature, only when the oil temperature of the working oil is lower than a predetermined lower limit value. High pressure injector for the injection device. 4. The fuel injection device according to claim 1, wherein the high-pressure fuel injection device is an electronically controlled hydraulically driven fuel injection device.
The high-pressure injector of the high-pressure fuel injection device according to any one of the above.