FR2951783A1 - PRESSURE REGULATOR FOR A DIESEL INJECTION DEVICE COMPRISING MEANS PROVIDING DEGRADE MODE OPERATION, HEAT ENGINE COMPRISING SUCH AN INJECTION DEVICE AND VEHICLE - Google Patents

Abstract

The invention relates to a pressure regulator for diesel injection device comprising means ensuring operation in degraded mode, a heat engine comprising such an injection device and vehicle. The regulator according to the present invention comprises means for maintaining the rod at rest in a closed position. Advantageously, said means for holding the rod (39) are biasing means preferably comprising a spring. Advantageously, the spring (45) is arranged to exert on the rod a force in the opposite direction to that exerted by the closing spring rest, usually arranged in the regulators. Thus, according to the present invention, the regulator is able to operate in degraded mode without power supply, the opening of the nozzle being ensured by the pressure in the accumulator pushing the rod (39) when this pressure is sufficient, in view of the surface on which it is exerted inside the regulator to push said rod in view of the load in place of the return spring. The present invention applies in particular to the automotive industry. The present invention applies primarily to the diesel engine industry.

Description

Pressure regulator for a diesel injection device comprising means ensuring operation in degraded mode, a heat engine comprising such an injection device and a vehicle.

The present invention mainly relates to a pressure regulator for a diesel injection device comprising - in addition to the functionalities of already existing regulators - means ensuring operation in degraded mode in case of failure, to a heat engine comprising such a device. regulator and to a vehicle comprising such an engine. The diesel engine for a motor vehicle (typically a vehicle of less than 3.5 × 10 6 g) of known type typically comprises a plurality of cylinders, each equipped with a high-pressure injector ensuring, on electrical control, the injection of fuel gas oil. at a pressure which may reach or exceed 2.5 108 Pa. Each injector comprises an injection chamber connected firstly to a high-pressure accumulator called a "rail" or "common rail" and secondly to a high-pressure accumulator. , an injection hole connected to the cylinder to be fed. An injector needle disposed in the pressure chamber is driven by an electric actuator such as an electric coil / magnet, an electromagnet or a piezoelectric actuator, between a first injection position in which the pressure chamber is connected. at the injection hole and a second position in which the needle obstructs the passage between the pressure chamber and the injection hole. A known type regulator comprises a discharge nozzle to the tank of gas oil at atmospheric pressure or above atmospheric pressure, the opening of which, in case of overpressure in the accumulator, is ensured, on command of a computer, by an electric actuator, for moving a rod whose one end ensures the hermetic closure of the nozzle. In known manner, the regulator comprises a return spring of the rod to the open position, ensuring the placing in communication, at rest, the accumulator (high pressure) with the reservoir (low pressure). This avoids the formation, unwanted, of air pockets, especially during temperature variations, for example, during cooling of the engine after stopping. A regulator comprising a spring having a return force directed in the same direction as that exerted by the electric actuator is described in DE 102 14 084 40 which is incorporated by reference. However, this regulator is not intended for pressure regulation in case of power failure.

The Applicant has discovered that, surprisingly, a slightly modified regulator makes it possible to inject diesel into the cylinders at an operating pressure of the engine, even in the event of non-operation of the electric drive actuator of the rod. for example in case of power failure. Degraded mode operation of the diesel engine is carried out at a slightly reduced power, with a reduced maximum torque, for example equal to 0.75 times the available torque when the injection device is operating normally, and 50 with a degraded energy efficiency. Advantageously, the degraded mode operation can be carried out continuously for several hours, or, preferably for at least ten hours with an acceptable heating, not risking a degradation of the engine.

Thus, the device according to the present invention is particularly reliable and allows robust operation.

The regulator according to the present invention comprises means for maintaining the rod at rest in a closed position. Advantageously, said rod holding means are biasing means preferably comprising a spring. Advantageously, the spring is arranged so as to exert on the rod a force in the direction opposite to that exerted by the closing spring at rest, usually arranged in the regulators. Thus, according to the present invention, the regulator is able to operate in degraded mode without power supply, the opening of the nozzle being provided by the pressure in the accumulator pushing the rod when this pressure is sufficient, in view of the surface on which it is exerted inside the regulator to push the said rod in view of the load in place of the return spring.

Advantageously, the profits and dimensions of the seat of the regulator, forming nozzle are adapted so as to obtain diesel pressures (function of the flow rate through said regulator) desired according to the engine power and customer wishes. Thus, we will have higher opening pressures and flow rates for more powerful engines, especially for large vehicles, sports vehicles, trucks and off-highway vehicles.

The subject of the invention is mainly a pressure regulator for a high-pressure diesel fuel tank of a diesel engine injection device comprising a nozzle for reducing the pressure prevailing in said accumulator, means for closing said nozzle as well as an electrically actuated actuator for closing and holding in a closed position said nozzle closure means characterized in that it further comprises elastic return means of the nozzle closing means, to the closed position with a force allowing the pressure regulation of the accumulator in case of failure of the actuator.

The invention also relates to a regulator characterized in that the actuator is an electromagnetic actuator and in that the elastic return means to the closed position comprise a spring exerting a force substantially in the same direction as that exerted by the actuator. 'actuator.

The invention also relates to a regulator characterized in that the closure means comprise a rod and in that the elastic return means to the closed position comprise a spring disposed coaxially with said rod. The subject of the invention is also a regulator characterized in that one end of the nozzle closing rod comprises a ball that is applied to a nozzle seat. The subject of the invention is also a regulator characterized in that the nozzle forms an angle of between 50 ° and 180 ° with respect to the axis of a channel capable of being connected to said accumulator.

The invention also relates to a regulator characterized in that the seat has a diameter of between 0.9 and 2.0 mm.

The invention also relates to a regulator, characterized in that the nozzle is dimensioned so that, in the absence of power supply to the actuator, the opening pressure (at 0 1 / h) is between 15 106 Pa to more than 80 106 and adapted to the motor need for flow rates up to 420 1 / h through said regulator.

The invention also relates to a regulator, characterized in normal operating mode by a pressure regulation and a rapid pressure discharge in case of release of the accelerator pedal identical to those of pressure regulator currently implemented .

The subject of the invention is also a diesel injection device characterized in that it comprises a high-pressure gas-oil accumulator fed by a high-pressure pump, said accumulator being connected on the one hand to a plurality of high-pressure injectors and on the other hand, to a regulator.

The invention also relates to a diesel engine characterized in that it comprises an injection device.

The invention also relates to a vehicle characterized in that it comprises a motor.

The present invention will be better understood by means of the description below and the figures given as non-limiting examples and in which:

- Figure 1 is a sectional view of a known type of regulator; FIG. 2 is a performance diagram of such a regulator in the normal case of operation; FIG. 3 is a diagrammatic sectional view of the preferred embodiment of the regulator according to the present invention; FIG. 4 is a diagram illustrating the performance of the regulator according to the present invention in normal operation and degraded operation; FIG. 5 is a detailed sectional view of the preferred embodiment of the regulator according to the present invention; - Figure 6 is a schematic sectional view of a controller according to the present invention; FIG. 7 is a view on a larger scale of the hydraulic part comprising the nozzle of the regulator of FIG. 6; FIG. 8 is a view of an injection device according to the present invention; Figure 9 is a partially broken away perspective view of a vehicle according to the present invention; - Figure 10 is a perspective view with partial cutaway, on a larger scale, the engine according to the present invention of the vehicle of Figure 9; Figure 11 is a sectional view of the preferred embodiment of a seat used in the regulator according to the present invention.

In Figures 3 to 11, the same references were used to designate the same elements.

FIG. 1 shows a regulator 1 of known type comprising a nozzle 3, an inlet 5 of which is connected to the pressurized diesel fuel tank and whose low pressure outlet channels 7 are capable of being connected to the fuel tank. diesel fuel. A rod 9 provides, on the control of a computer, the closure of the nozzle 3, for example by applying a ball 11 on a seat of the nozzle 3. The regulator 1 comprises an actuator 13 driving the rod 9 to the closed position comprising for example a fixed coil and a magnetic core secured to the rod 9.

The known type regulator further comprises a return spring 15 ensuring the opening, at rest of the regulator ensuring the placing of the accumulator at atmospheric pressure when the engine is stopped. Thus, the force exerted by the actuator 13, illustrated by the arrow F13 in Figure 1 is directed downwardly of this figure while the force exerted by the spring 15, illustrated by the arrow F15 is directed towards the top of the In other words, the forces exerted by the actuator and the spring are in opposite directions. This has the major disadvantage that in case of electrical failure of said regulator, it remains open no longer ensuring the maintenance in the accumulator of a minimum pressure necessary for the injection system and therefore no operation even degraded is not possible.

In Figure 2, we can see a diagram for the known type of regulator expressing the pressure 17 expressed in 105 Pa as a function of the flow rate 19 expressed in liters per hour. In the diagram, a zone 21 corresponds to the electrical operation for regulating pressure in the accumulator and a lower zone 23 in which the pressure control is not stable.

The zones 21 and 23 are separated by a line segment 25 starting from a few liters per hour for a pressure of the order of 20 ... 25 106 Pa and passing through a point corresponding to a flow rate of 200 liters per hour and a pressure substantially equal to 75 106 Pa.

FIGS. 3, 5 and 6 show a regulator 1 according to the invention comprising a nozzle 33 whose inlet 35 is connected to the pressurized diesel fuel tank and whose low pressure outlet channels 37 are capable of be connected to the fuel tank of the vehicle. A rod 39 provides, on command of a computer, the closure of the nozzle 33, for example by applying a ball 41 to a seat of the nozzle 33. The regulator 31 comprises an actuator 43 for driving the rod 39 to the closed position comprising for example a fixed coil 57 and a magnetic core 55 secured to the rod 39.50 The regulator according to the invention further comprises a return spring 45 providing a closing force of the regulator ensuring the generation of a pressure in the accumulator in case of power failure. Thus, the force exerted by the actuator 43, illustrated by the arrow F43 in Figure 3, and the force exerted by the spring 45, illustrated by the arrow F45 in this figure, are directed downwards. In other words, the forces exerted by the actuator 43 and the spring 45 are of the same direction.

In Figure 4, we can see a control diagram of an embodiment of the regulator according to the present invention for trucks. It is understood that the pressures and flow rates to be obtained are a function of the desired type of operation of the diesel engine. In FIG. 4, the pressure 47 expressed at 105 Pa is expressed as a function of the flow rate 49 expressed in liters per hour. An upper zone 51 allows the regulation of the pressure typically using the actuator 43. A lower zone 53 not used does not allow pressure regulation by the pressure regulator. The zones 51 and 53 are separated by a line segment 54 connecting the point defined by a flow rate of a few liters per hour and a pressure of the order of 80 106 Pa at the point defined by a flow rate of 420 liters per hour and a pressure substantially equal to 120 106 Pa.

The nominal operating pressure (normal, non-degraded mode) can vary from 1.8 to 2.7 to 108 Pa.

It should be noted that the straight segment 54 corresponds to the operation of the regulator controlled solely by the spring 45, the actuator 43 being not powered.

Preferred examples of operation of a regulator for various applications are given below: for a particular (light) vehicle, the straight segment 54 is preferably between a flow rate of 2 liters per hour at a pressure of at 25 106 Pa, at a flow rate of 100 liters per hour for a pressure 50.106 Pa

For a large sedan, the straight segment 54 is preferably between a flow rate of 2 liters per hour at a pressure of 15 to 25 106 Pa, at a flow rate of 200 liters per hour for a pressure 70.106 Pa.

for a brake vehicle, the right-hand segment 54 is preferably a flow rate of 2 liters per hour at a pressure of 15 to 10 6 Pa, at a flow rate of 200 liters per hour for a pressure of 70 × 10 6 Pa

for a van, the straight segment 54 is preferably between a flow rate of 2 liters per hour at a pressure of 25 to 106 Pa, at a flow rate of 100 liters per hour for a pressure of 50 × 10 6 Pa.

for a race car, the straight segment 54 is preferably between a flow rate of 2 liters per hour at a pressure of 50 to 70 × 10 6 Pa, at a flow rate of 200 liters per hour for a pressure of 120 × 10 6 Pa for a light truck, the straight segment 54 goes, preferably between a flow rate of 2 liters per hour, at a pressure 30 to 106 Pa, at a flow rate of 150 liters per hour for a pressure 60.106 Pa - for a truck mean, the straight segment 54 is preferably a flow rate of 2 liters per hour, at a pressure of 30 to 60 106 Pa, at a flow rate of 150 liters per hour for a pressure 60.106 Pa

for a heavy truck or off-highway machinery, the straight segment 54 is preferably between a flow rate of 2 liters per hour at a pressure of 50 to 80 106 Pa, at a flow rate of 250 to 420 liters per hour for a pressure 70 to 120.106 Pa

In the preferred embodiment of the regulator according to the present invention, the rod 39 is biased towards the closed position of the nozzle by a helical spring 15 coaxial with this rod bearing on the one hand, preferably on the body of the regulator and on the other hand on a magnetic core 55 secured to the rod 39 or on the end of this rod. In the illustrated example, the actuator 43 is constituted by a coil 57, advantageously coaxial with the rod 39 attracting when it is traversed by an electric current the magnetic core 55 20 driving the rod 39. The spring guide is ensured either in the regulator body or on the magnetic core.

It is understood that the implementation of other actuators such as piezoelectric actuators or others are not beyond the scope of the present invention.

It is understood that the implementation of other return means, the rod 39 to the closed position, electrostatic elastic or other is not beyond the scope of the present invention. In such a case, the curve 54 separating the zones 51 and 53 is not necessarily a straight line segment.

In Figure 7, we see the preferred embodiment of the hydraulic part consisting of a nozzle 33 implemented in a controller 31 according to the present invention. The hydraulic part comprises an end pin 39 guiding a ball 41 which seals in a closed state on a substantially frustoconical hydraulic seat part 61 extended by the outlet channel 47 connected to the accumulator. As previously indicated, the regulator pressure as a function of flow is optimized for the operation of the engine in degraded mode. For example, the pressure prevailing in the accumulator 40 (in the absence of a power supply) is equal to 15 to 80 × 10 6 Pa. The force of the spring 45 is chosen so that the nozzle is closed (in the absence of a power supply). ) for pressures of 15 to 80.106 Pa (opening pressures). For example, a spring having a stiffness of between 5 N / mm and 300 N / mm is used. An increase in the stiffness of the spring contributes to the stability of the pressure regulator in normal mode while a decrease in this stiffness favors the limitation of the pressure prevailing in the accumulator in degraded mode.

The seat 61 advantageously forms an angle of between 50 and 180 ° to ensure the stability of the pressure regulation. The seat diameter is advantageously between 0.9 mm and 2 mm. An increase in the diameter of the nozzle respectively of the seat makes it possible to ensure degraded mode low pressures at high oil flow rates at the cost of an increase in the spring force during the establishment of the seal. The diameter of the seat (not shown) depends on the angle and the diameter of the ball 41. Advantageously, it limits the bulk of the ball, which should preferably be less than a few mm.

It is understood that the implementation of other types of nozzles, for example nozzles ball, for example of the type in which the end 59 of the rod 39 is applied directly to the seat (including 59 flat end, rounded or otherwise) is not outside the scope of the present invention.

The opening pressure of the nozzle valve corresponds to the minimum acceptable pressure level for the (re) start of the motor in the event of electrical failure of the pressure regulator for degraded operation of the motor in case of electrical failure of the pressure regulator. It varies for example from 15 106 Pa to more than 80 106 Pa. However, this maximum pressure should not too much limit the regulation range in normal mode below the right segment 54.

It should be noted that the regulator according to the present invention not only makes it possible to compensate for an electrical failure of this regulator such as caused by a rupture of the wiring harness of the engine computer, but also a case combined with a failure of a unit. dosing of the high pressure pump (electrical failure or mechanical blockage). In this case of double failure, the regulator according to the present invention allows operation in degraded mode of the motor up to flow rates by the regulator of up to 420 1 / h. Above the segment 54, it should be noted that the regulator according to the present invention allows, in normal operating mode, a pressure regulation as well as a rapid pressure discharge in the event of the release of the accelerator pedal identical to those of pressure regulator currently implemented.

In addition, a regulator according to the present invention can be easily manufactured from pressure regulators already implemented with great control of the opening pressure dispersions and with a small drift over time. The present invention also relates to a vehicle 63, such as for example illustrated in Figure 9, comprising a diesel engine 67 as best seen in Figure 10.

The object of the invention is not only light vehicles, as illustrated in FIG. 9, but also vans, trucks or off-highway machines such as construction machines or boats. The vehicle 63 comprises a reservoir 69 connected by a low pressure connection 71 to a high pressure pump 73 advantageously through a fuel filter 75. The output of the high pressure pump 73 is connected by a high pressure connection 77 to an accumulator or rail40. A regulator 31 according to the present invention is advantageously disposed at one end of the accumulator 65 furthermore provided with a pressure sensor 79 connected by an electrical connection to an electronic calculator EDC 81. The accumulator 65 is connected by means of high pressure connections 77 to a plurality of injectors 83 (typically one per cylinder 85).

Advantageously, the motor further comprises an air mass flowmeter 87 connected to the computer 81, a speed sensor 89 of a crankshaft 91, a sensor 93 of the coolant temperature of the engine 67 and an accelerator pedal 10 provided with a position sensor of said pedal.

The present invention applies in particular to the automotive industry and heavy weight.

The present invention is primarily applicable to the diesel engine industry. 20 25 30 35 40 45 50 NOMENCLATURE

1 Regulator 3 Nozzle Inlet 7 Outlet channel 9 Stem 11 Ball 13 Actuator Spring 15 17 Pressure 19 Flow 21 Control zone 23 Unstable zone 25 Straight segment 31 Regulator 33 Nozzle 35 Inlet 37 Exit channel 39 Shaft 41 Ball 43 Actuator 45 Spring 47 Pressure 49 Flow 51 Control zone 53 Not used zone 54 Right segment 55 Magnetic core 57 Coil 59 Rod end 61 Seat 63 Vehicle 65 Accumulator / rail 67 Engine 69 Tank 71 Low pressure link 73 HP 75 pump Fuel filter 77 High pressure link 79 Pressure sensor 81 Calculator 83 Injectors 85 Cylinders 87 Flowmeter 89 Crankshaft speedometer 10 Crankshaft 93 Temperature sensor 95 Accelerator pedal 10 15 20 25 30 35 40 45 50

Claims (11)

REVENDICATIONS1. A pressure regulator for a high-pressure diesel fuel accumulator (65) of a diesel engine injection device comprising a nozzle (33) for reducing the pressure in said accumulator (65), means (39, 41, 59, 61) of said nozzle and an actuator (43) with electrical control closing and holding in a closed position of said nozzle closure means characterized in that it further comprises means (45) of resilient return of the nozzle closing means, to the closed position with a force allowing the pressure regulation of the accumulator (65) in case of failure of the actuator (43). 2. Regulator according to claim 1 characterized in that the actuator (43) is an electromagnetic actuator and in that the means (45) for resilient return to the closed position comprise a spring exerting a force (F45) substantially in the same direction as that (F43) exerted by the actuator (43). 3. Regulator according to claim 1 or 2 characterized in that the closure means comprise a rod (39) and in that the elastic return means (45) to the closed position comprise a spring disposed coaxially with said rod (39). ). 25 4. Regulator according to claim 3 characterized in that one end (59) of the rod (39) closing the nozzle (33) comprises a ball (41) applying to a seat of the nozzle (33). 30 5. Regulator according to any one of the preceding claims characterized in that the nozzle (33) forms an angle of between 50 ° and 180 ° relative to the axis of a channel capable of being connected to said accumulator. 6. Regulator according to any one of the preceding claims, characterized in that the seat has a diameter of between 0.9 and 2.0 mm. 7. Regulator according to any one of the preceding claims, characterized in that the nozzle (33) is dimensioned so that, in the absence of power supply of the actuator (43), the opening pressure (at 0 40 1 / h) is between 15 106 Pa to more than 80 106 and adapted to the motor as needed for flow rates up to 420 1 / h through said regulator. 8. Regulator according to any one of the preceding claims characterized in normal operating mode by a pressure control 45 and a rapid pressure discharge in case of release of the accelerator pedal identical to those of pressure regulator currently set implemented. 9. A diesel injection device characterized in that it comprises a high pressure gas accumulator (65) (43) fed by a high pressure pump (73), said accumulator (65) being connected on the one hand to a plurality high pressure injectors (83) and, secondly, a regulator (31) according to any one of the preceding claims. 10. Diesel engine characterized in that it comprises an injection device according to claim 9. 11. Vehicle characterized in that it comprises an engine according to claim 10.10