JP2004520234A - Fuel supply device with vapor extraction function - Google Patents

Abstract

The present invention relates to a method and apparatus for withdrawing fuel vapors moved during simultaneous operation of at least two fuel supply units using a gas pump device. Each fuel supply unit includes a steam extraction pipe in which a control valve is arranged. These vapor extraction tubes are connected to one gas pump device. The negative pressure to be generated by the gas pump device, which is important for the discharge of the correct amount of steam, is determined. Thereafter, each control valve is adjusted so that an accurate amount of steam flows at a predetermined negative pressure.

Description

[0001]
The present invention relates to a method for withdrawing fuel vapors moving during operation of at least two fuel supply units simultaneously using a gas pump device.
[0002]
According to national and international regulations for limiting environmental pollution, fuel supply devices, such as fuel pumps, need to have a vapor extraction function. During filling of a vehicle's fuel tank, fuel vapor present in the tank is displaced by fuel transported into the tank. The transferred steam needs to be discharged and returned to the fuel supply tank of the gas station. While the steam travels from the vehicle tank, the same amount of fuel is evacuated from the supply tank so that the vapor transferred from the vehicle fuel tank can easily occupy the fuel supply tank. When refilling the fuel supply tank, the transferred steam is stored in the fuel tank of the tank truck in the same manner, and the tank truck transports this steam to the fuel storage. In the storage, a device for processing the steam is made available. A closed system that emits little or no fuel vapor to the environment is thus obtained.
[0003]
In a known fuel supply device, there is a gas pump that extracts fuel vapor moved from a fuel tank of a vehicle and feeds the vapor to a fuel supply tank of a gas station. Open connection between the extraction pipe and the fuel tank of the vehicle at the filling opening of the tank, so that the flow rate of the fuel vapor is exactly adapted to the flow rate of the fuel fed into the vehicle tank by the supply unit. Need to be done. To achieve this, each fuel supply device is provided with a gas pump and a control valve in the steam extraction pipe. This control valve is designed so that the correct amount of steam is withdrawn. To this end, the control device comprises a memory storing characteristics of the relationship between the position of the control valve and the withdrawn steam flow rate.
[0004]
Devices that can simultaneously supply fuel using two fuel supply units are known per se. In this case, a choice is usually made between different types of fuel. Such a device is commonly referred to as a multi-product dispenser (MPD). Conventionally, each unit is provided with a gas pump and a control valve in order to withdraw fuel vapor well and to simultaneously supply fuel using, for example, two fuel supply devices. Is controlled. Fueling on one side does not affect the withdrawal on the opposite side. Such multiple forms of vapor discharge necessarily entail a relatively high cost of the fuel supply device.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is a method for extracting fuel vapor moved during simultaneous operation of at least two fuel units using a gas pump device, which can be performed by a fuel supply device that can be manufactured at low cost. To provide.
[0006]
According to the invention, said object is achieved by applying the method according to the invention, characterized in claim 1. As a result, only one gas pump device is required, even when supplying fuel from a plurality of fuel supply units simultaneously.
[0007]
If fuel is supplied simultaneously by multiple fuel supply units, the pump device will have to carry more steam. By applying the method according to the invention, a predetermined negative pressure is generated by the pump device. The control valve of each fuel supply unit is adjusted so that the correct amount of steam is withdrawn at a predetermined negative pressure to match the amount of fuel supplied by each fuel supply unit. For this purpose, the valve characteristics of each control valve at a given negative pressure are determined.
[0008]
In a preferred embodiment according to the invention, the pump device is controlled such that a predetermined negative pressure is generated on the suction side substantially independently of the withdrawn flow rate. Therefore, the valve characteristics need only include the relationship between the valve position and the steam flow that can flow through the valve at the predetermined negative pressure. Therefore, the operation of the control valve is simple.
[0009]
In the present application, the method according to claim 3 is suitably applied. A feedback valve housed in a feedback tube connected to the suction side and the discharge side of the gas pump of the pump device is controlled in order to generate a predetermined negative pressure irrespective of the withdrawn flow rate. The control of this feedback valve is performed so that the negative pressure measured on the suction side of the gas pump is kept constant.
[0010]
Yet another suitable embodiment is characterized by claim 4. Control of the control valve is further complicated, but in this embodiment it is not necessary to perform a corresponding control on a separate feedback valve.
[0011]
The invention also relates to and provides a dual fuel supply system as claimed in claim 5.
[0012]
Further advantages and features of the present invention will become apparent from the following description of several embodiments with reference to the accompanying drawings.
[0013]
FIG. 1 shows a first embodiment of a device 1 for simultaneous dual supply of fuel. The device comprises three double supply units 2. Each double supply unit 2 can simultaneously supply a specific fuel, in this case, for example, low octane gasoline, high octane gasoline, and unleaded gasoline, by means of two supply nozzles 3. Therefore, as the case may be, one of the three supply nozzles on each side of the double supply unit 2 is selected.
[0014]
In a manner known per se and thus not shown, fuel is conveyed from the fuel supply reservoir 6 to each supply nozzle 3 and from there into the fuel tank of the vehicle.
[0015]
Each fuel nozzle 3 is provided with a steam pipe 4 having an opening near the outlet opening of the nozzle 3. Fuel vapor moved from the fuel tank of the vehicle is withdrawn via the steam pipe 4. The steam tube can be housed in a conventional manner in a hose that supplies fuel to the nozzle.
[0016]
The steam pipe 4 has a valve 5. This valve 5 is closed when the corresponding fuel nozzle 5 is not used.
[0017]
Each steam pipe 4 is connected to a collector pipe 9 or 10. Each collector tube is arranged on one side of the device, so that during simultaneous dual supply of fuel using the device 1, both the collector tubes 9, 10 are used for vapor withdrawal. The control valves 11 and 12 are accommodated in the respective collector pipes 9 and 10. The control valves 11 and 12 are connected to the steam extraction pipe 7 at their outlets. A gas pump device 8 is accommodated in the steam extraction pipe, and gas is sucked from the steam extraction pipe and transported to the supply reservoir 6.
[0018]
For each supply nozzle of each supply unit 2, a sensor for measuring the supply fuel flow rate is provided. These sensors are connected via a signal line 15 to a control unit 16, in particular a counter computer 17 thereof. This counter computer 17 processes the measurement signals in the usual way, whereby the fuel supply is displayed on a connected counter, optionally together with the price associated with the supply.
[0019]
The counter computer 17 is configured to send a flow signal for each side of the device 1 to the control device 18 of the control device 16 via the signal line 19. One of these flow signals is sent via a line 19 to the AND port 20 and the other is sent to a so-called chopper described later. The control device 18 further comprises two memories. The first memory 22 has the valve characteristics (described later) of the valves 11 and 12, and the second memory 21 has the characteristics of the gas pump device 8. Therefore, the amount of fuel supplied on both sides of the device 1 is summed at the AND port 20. This total amount of fuel is sent to a part of the control device 18 having the memory 21. The pump characteristics stored in this memory relate to the relationship between the negative pressure on the suction side of the pump 8 and the withdrawn steam flow. As is known, the negative pressure on the suction side of the gas pump device 8 decreases so that more gas must be withdrawn by the gas pump device. The relationship between the negative pressure and the amount of steam withdrawn is a characteristic for a particular pump 8 and is predefined and stored in the memory 21.
[0020]
The control device 18 uses the characteristics in the second memory 21 to determine what the value of the vacuum in the tube 7 will be during the extraction of an amount of steam equal to the amount of fuel supplied. This negative pressure signal is sent to a first memory 22 having the characteristics of the valves 11 and 12. This property relates to the relationship between valve position, negative pressure, and the flow rate of steam that can flow through the valve. The negative pressure to be set is determined based on the pump characteristics in the second memory 21, and the steam flow rate for each supply unit is sent to the first memory 22. The valve position to be set at the instantaneous flow rate and the negative pressure is derived from the valve position in the memory 22. A control signal for this valve position is sent to the corresponding control valve 11 or 12 via a control line 24.
[0021]
The chopper 23 ensures that the flow rates for each valve are sent alternately to the first memory 22 and at the same time the determined control signal is sent to each control valve 11 or 12. This is done using a suitable AC frequency such that the valves 11, 12 are operated semi-continuously.
[0022]
When the fuel supply changes on one or both sides of the device 1, the position of the two control valves 11, 12 is adjusted by the control device 16, so that the correct amount of steam is discharged on the side in question. to continue. For example, if the fuel supply is stopped on the side of the device 1 where the control valve 11 is located, the amount of steam to be withdrawn is limited to an amount corresponding to the amount of fuel supplied on the opposite side. As a result, the negative pressure in the extraction pipe 7 increases, but the control valve 12 needs to be controlled to the closed side so that the same flow rate can be passed.
[0023]
FIG. 2 shows a second embodiment 31 of the device for simultaneous dual supply of fuel. The device comprises three double supply units 32. Each double supply unit 32 can simultaneously supply a specific fuel through two supply nozzles 33.
[0024]
Each fuel nozzle 33 is provided with a steam pipe 34 having an outlet near the outlet opening of the nozzle 33. The fuel vapor transferred from the fuel tank of the vehicle is withdrawn through the steam pipe 34 and finally enters the fuel supply reservoir 36.
[0025]
The steam pipe 34 has a valve 35. This valve 35 is closed when the corresponding fuel nozzle 33 is not used.
[0026]
Each steam pipe 34 is connected to a collector pipe 39 or 40. Each collector tube is provided on one side of the device, so that during simultaneous dual delivery of fuel using device 31, both collector tubes 39, 40 are used for vapor withdrawal. The control valves 41 and 42 are arranged on each of the collector pipes 39 and 40. The control valves 41 and 42 are both connected at their outlets to the steam extraction pipe 37. The vapor extraction pipe 37 is connected to the suction side of the pump device 43. The gas pump 38, the feedback control valve 44, and the pressure measuring device 45 are arranged in this pump device. The gas pump 38 sucks gas from the steam extraction pipe and conveys the gas to the supply reservoir 36. The pressure measuring device 45 is connected to the suction side of the pump device 43, and measures the negative pressure of the vapor extraction pipe 37. The feedback control valve 44 is connected to the suction side and the discharge side of the gas pump 38. Via the feedback control valve 44, the gas can flow back from the discharge side of the gas pump 38 to the suction side.
[0027]
A sensor for measuring the supply fuel flow rate is provided for each supply nozzle of each supply unit 32. These sensors are connected via a signal line 46 to a control device 47, in particular a counter computer 48 thereof. This counter computer 48 processes the measurement signals in the usual way and forms a first measurement unit.
[0028]
The counter computer 48 is configured to send a flow signal for each side of the device 31 to the control device 50 of the control device 47 via the signal line 49. The control device 50 comprises a memory 54 containing the valve characteristics of the valves 41, 42 under the determined predetermined negative pressure. This property relates to the relationship between the valve position and the steam flow that can flow through the valve. After processing the information from the memory 54, a control signal is generated for each control valve 41, 42, which determines the position of each control valve corresponding to the required withdrawal flow rate. This control signal is sent to each valve 41 or 42 via the chopper 52 and the control line 53.
[0029]
The chopper 52 ensures that the flow rates for each valve are alternately sent to the memory unit 22 and at the same time that the determined control signal is sent to each control valve 41 or 42. This is done using a suitable AC frequency such that the valves 41, 42 are operated semi-continuously.
[0030]
The gas pump 38 has sufficient pump capacity to handle the withdrawal steam volume at the maximum total flow of the fuel supply device. Under a negative pressure set at 200 mbar, the gas pump can withdraw, for example, 2 × 45 l / min of steam at the maximum total flow rate of the two fuel nozzles 33, for example.
[0031]
The pressure measuring device 45 measures a negative pressure at the time of suction of the gas pump 38. In the control unit 50, this measurement signal is compared with a reference signal stored in the memory 54. Using the difference signal, the control valve 44 is controlled so that the difference goes to zero. As described above, by using the selected reference signal, the negative pressure at the time of suction of the gas pump 38 can be made constant.
[0032]
If the negative pressure is too high, the position of the control valve 44 is changed to reduce the negative pressure. The reverse is also true.
[0033]
When the fuel supply changes on one or both sides of the device 31, the position of the corresponding control valve 41 and / or 42 is adjusted by the control device 47 so that the correct amount of steam on the side in question is produced. Continue to be discharged. For example, when the fuel supply is stopped on the side of the device 1 where the control valve 41 is disposed, the amount of steam withdrawn is limited to an amount corresponding to the amount of fuel supplied on the opposite side. In order to maintain the negative pressure at the determined predetermined value, the set value of the feedback valve is modified so that the predetermined negative pressure is reset. The control valve 41 is closed. There is no change for the control valve 42.
[0034]
The pump device may be configured to be used with a mechanical pressure measuring device and a control valve instead of being used with an electronic controller.
[0035]
FIG. 3 shows a cross-sectional view of such a mechanical control device. The assembly 61 comprises two partial housings 62, 63, the space being divided into two chambers 64, 65. The chambers are separated by a membrane 66. The chamber 64 is connected to both the suction side 67 and the discharge side 68 of the gas pump 69. The negative pressure generated by the gas pump spreads to the chamber 64. In response to this negative pressure, the membrane 66 makes the chamber 64 smaller or larger. For this purpose, the membrane 66 is arranged between the two spring means 70, 71 on both sides of the membrane 66 of the two chambers 64, 65. The spring means 70 comprises a spring 72 arranged between the two spring cups 73,74. The cup 73 is connected to the membrane 66. The cup 74 engages an adjusting screw 75 protruding outside the housing part 63. The adjusting screw 75 can be tightened, whereby the spring means 70, 71 are compressed and the holding position of the membrane is changed.
[0036]
Using the adjusting screw 75, a predetermined negative pressure value can be set according to the function of the pump device as described above.
[0037]
The membrane 66 is connected to an end of the lever 76. The lever 76 is mounted on a projecting arm 77 which is screwed and fixed in the housing part 62. The other end of the lever is connected to a valve member configured as a slide 78. This slide 78 is arranged on a tube stub 79 connected to the discharge side 68 of the gas pump 69. The tube stub 79 is provided with an opening 80 for communicating the chamber 64 with the discharge side 68 of the gas pump 69. Opening 80 and chamber 64 form a feedback tube. The slide 78 forms a feedback control valve to increase or decrease the degree of closing of the opening 80 to increase or decrease the degree of opening of the feedback tube.
[0038]
If the negative pressure on the suction side is too strong, the membrane 66 tends to move to the left side in FIG. At this time, the slide 78 moves to the right side in FIG. 3 via the lever 76, whereby the opening 80 is further opened. As a result, more gas flows from the discharge side 68 of the gas pump 69 to the suction side 67, thereby reducing the negative pressure. If the vacuum is too low, the opposite effect occurs, whereby the vacuum builds up again. In this way, the negative pressure on the suction side of the gas pump 69 is kept substantially constant regardless of the amount of steam withdrawn.
[0039]
An advantage of this control device and the device shown in FIG. 2 is that changes in the capacity of the gas pump over time, for example due to wear and fouling, are compensated for. The reason for this is that a certain negative pressure is nevertheless maintained by the control device.
[0040]
A further advantage of the mechanical embodiment of FIG. 3 is that it is relatively inexpensive.
[Brief description of the drawings]
[0041]
FIG. 1 shows a schematic diagram of a first embodiment.
FIG. 2 shows a schematic diagram of a second embodiment.
FIG. 3 shows a sectional view of a part of a pump device according to a third embodiment.

Claims (10)

A method for extracting fuel vapor moved during simultaneous operation of at least two fuel supply units using a gas pump device, wherein each fuel supply is provided with a respective control valve and connected together on the suction side of the gas pump device. Including providing a steam extraction tube for the unit,
The method further comprises:
Measuring the individual fuel flow supplied by each fuel supply unit;
Driving the pump device to create a predetermined negative pressure on the suction side of the pump device, pumping a steam flow substantially equal to the sum of the individual fuel flows;
For each control valve, predetermining valve characteristics that represent a relationship between valve position and a steam flow rate capable of flowing at least at the predetermined negative pressure;
Determining a valve position at the predetermined negative pressure and an individual fuel flow rate of a fuel supply unit corresponding to each control valve, based on valve characteristics for each control valve;
Adjusting each control valve to the determined valve position. 2. The method of claim 1, wherein the pump device generates the predetermined negative pressure on the suction side substantially independent of the withdrawal flow rate. The pump device includes a gas pump having a suction side and a discharge side, a feedback pipe having a feedback valve and connected to the suction side and the discharge side, and a pressure measurement device connected to the suction side,
Measuring the negative pressure on the suction side during operation;
Adjusting the feedback valve such that the predetermined negative pressure is substantially maintained. Pre-determining pump characteristics indicative of a relationship between different negative pressures on the suction side and a withdrawn steam flow rate,
The determined valve characteristics include the relationship between valve position, steam flow allowed to flow through the valve, and different negative pressures,
The method of claim 1 wherein said predetermined negative pressure is a negative pressure at a steam flow equal to the sum of the individual fuel flows based on gas pump characteristics. In a fuel simultaneous dual supply device having a plurality of fuel supply units,
Each fuel supply unit is
A fuel pipe provided with a fuel pump,
A supply nozzle connected to the fuel pipe;
A collector pipe for the steam that is connected to and moved to each supply nozzle, wherein a control valve is provided in each collector pipe;
A pump device connected to the collector tube on the suction side and capable of generating a predetermined negative pressure on the suction side;
A control device;
The control device comprises:
A first measuring unit for measuring a fuel flow supplied by each fuel supply unit;
A first memory containing, for each valve, valve characteristics representing a relationship between the valve position and the steam flow capable of flowing at least at a predetermined negative pressure;
Determining a valve position at the predetermined negative pressure and an individual fuel flow rate of a fuel supply unit corresponding to each valve based on valve characteristics of each valve, and adjusting each valve to the determined valve position. Control unit and
A device comprising: The pump device comprises a gas pump,
The first memory includes, for each valve, valve characteristics representing a relationship between valve position, negative pressure, and steam flow that can flow through the valve;
The control unit further
A second memory containing pump characteristics representing the relationship between the suction side negative pressure and the withdrawn vapor flow rate;
6. The device of claim 5, further comprising a second control unit for determining a negative pressure on the suction side of the gas pump at a steam flow equal to the sum of the individual fuel flows based on the pump characteristics. 6. The device according to claim 5, wherein the pump device comprises a gas pump, a feedback device connected to the suction side and the discharge side of the gas pump, and a pressure measuring device connected to the suction side of the gas pump. The feedback device includes a feedback pipe and a feedback control valve,
The memory further includes the determined predetermined negative pressure value,
The control unit further
A second measuring unit for measuring negative pressure;
A second control unit that determines a set value for the feedback control valve so that the predetermined negative pressure is maintained;
The device of claim 7, comprising: The feedback device includes a feedback pipe and a feedback control valve,
The pressure measuring device comprises at least two chambers separated by a membrane;
One chamber is connected to the suction side of the gas pump and the feedback pipe, whereby the negative pressure on the suction side can be determined by the position of the membrane, and the membrane is connected to the feedback control valve so that the predetermined negative pressure is maintained. The device of claim 7, wherein the device is connected to the feedback control valve by a lever for adjustment. A control device used for the device according to claim 5.