AU2018297616B2

AU2018297616B2 - Fuel dispenser comprising a two-speed motor and method for the operation thereof

Info

Publication number: AU2018297616B2
Application number: AU2018297616A
Authority: AU
Inventors: Laurent BORDIER
Original assignee: Tokheim UK Ltd
Current assignee: Dover Fueling Solutions UK Ltd
Priority date: 2017-07-07
Filing date: 2018-07-04
Publication date: 2023-10-19
Anticipated expiration: 2038-07-04
Also published as: CN110869311A; BR112020000306A2; FR3068687B1; FR3068687A1; PT3649075T; EP3649075A1; ES2881313T3; CN110869311B; WO2019008066A1; EP3649075B1; AU2018297616A1

Abstract

The invention relates to a fuel dispenser (1) comprising a pump unit (2) provided with an electric motor (3) that drives a pump (4) for sucking fuel from a fuel tank, the pump unit (2) being connected to two fuel-dispensing lines (5), each one comprising a flow-rate measuring device (6) connected to a hose (7) provided with a nozzle (8) for supplying fuel to a vehicle tank. According to the invention, the electric motor (3) is a two-speed motor with predefined speeds (3) providing the pump (4) with two rotational speeds, one of which is a low speed V1 for generating a slow fuel rate D1 out of the pump unit (2) when a single nozzle (8) supplies fuel, and the other is a high speed V2 for generating a fast fuel rate D2 out of the pump unit (2) when two nozzles (8) supply fuel, the two-speed motor (3) being electrically connected to a controller (9) controlling the speed of the electric motor (3) according to the number of nozzles (8) activated.

Description

FUEL DISPENSER WITH TWO-SPEED MOTOR AND ITS OPERATING METHOD

Art The subject matter of the present invention is a fuel dispenser with a two speed motor and operating method.

Prior art Generally, fuel dispensers found in filling stations include a pumping unit intended for suctioning up fuel into a storage tank. The pumping unit includes a pump that is driven by an electric motor and that is connected, in most cases, to two dispensing lines. Every dispensing line includes a fuel flowrate measuring element for measuring the volume of the fuel that is delivered, and a hose with a fuel dispensing nozzle that is actuated by the user when filling the tank of the vehicle thereof. The pump is a suction pump such as gear pump or a rotary vane pump that usually works at constant speed. Same supplies, on average, a flow-rate of 80 I/minute that is required for supplying a flow-rate of 40 I/minute in each of the two dispensing lines when two fuel nozzles are removed from the hook and actuated at full flow-rate for filling up two corresponding vehicle tanks placed on both sides of the fuel dispenser. However, when only one fuel nozzle of a pumping unit is active, the dispensing line has to continue to supply a maximum flowrate of 401/minute so as to comply with the standards in vigor. To achieve this, the pumping unit includes a so-called bypass circuit including a bypass valve, wherein the excess flowrate that is not used is drawn off in closed circuit in order to offload the pumping unit of a too high flowrate. The first function of the bypass circuit is to protect the pump from an overpressure which could destroy the pump. For this reason, the electrical power consumption of the motor is maximum throughout the pump operation, while the flowrate that is actually needed is often much lower when only one fuel nozzle is active. Only 50% of the flowrate is then useful. This lesser need represents 80% of the operating time of the pump.

There are solutions consisting of using a variable-frequency drive to control the rotation speed of the electric motor depending upon the fuel flowrate that is needed. It is possible to adjust the fuel flowrate by adjusting the frequency of the motor. When only one nozzle is removed from the hook, a control system sends a frequency setpoint value to the variable-frequency drive so that the latter turns the electric motor at a frequency allowing a flowrate of about 40 I/minute to be obtained. When two nozzles are removed from the hook, the control system send a frequency setpoint value to the variable-frequency drive so that the latter turns the electric motor at a higher frequency allowing for a flowrate of about 80 I/minute. However, this solution allows only for a partial (about 10%) saving of energy to be achieved. This is due to a loss of efficiency of the variable-frequency drive. Furthermore, variable-frequency drives are very expensive. The subject matter of the present invention is that of compensating for this disadvantage by proposing a fuel dispenser that would consume less electrical power that those of the prior art.

Description of the invention To this end, the invention relates to a fuel dispenser including a pumping unit with an electric motor driving a pump intended for suctioning up fuel from a fuel tank. The pumping unit is connected to two fuel dispensing lines, wherein each line includes a flowrate measuring element connected to a hose equipped with a fuel nozzle intended for dispensing fuel into a vehicle fuel tank. According to the invention, the electric motor is a motor with two predetermined speeds that supplies two rotation speeds of which one low speed V1 intended for supplying a low fuel flow-rate D1 at the output of the pumping unit when only one fuel nozzle supplies fuel and a high speed V2 intended for supplying a high flow-rate D2 at the output of the pumping unit when the two fuel nozzles supply fuel. The two speeds V1 and V2 are thus set and predetermined. The two-speed motor is electrically connected to a controller controlling the speed of the electric motor depending upon the number of active fuel nozzles.

According to one possible embodiment, the two-speed motor is an asynchronous motor operating with a variable number of poles. The fuel dispenser includes a means of switching that is controlled by the controller, used for switching from a number X of poles to a number Y of poles. According to one possible embodiment, the two-speed motor operates with 4 poles or with 8 poles so as to obtain the set speed V2 or V1 respectively. The invention thus provides a fuel dispenser that consumes 30% less electrical power per electric motor than classical fuel dispensers, during 80% of the operating time of the fuel dispenser. By comparison, using a frequency controller allows the electrical power consumption to be reduced, at best, by 10%. Moreover, this solution is more expensive than that of the invention. It is also possible to call-upon the bypass circuit less, thus reducing fuel overheating. The noise level of the filling station is also reduced by a reduction of the speed at the pump, and hence of the maximum fuel flowrate during critical times (night or intense heat). Moreover, variable-frequency drives up take space because of the radiators on the thyristors. Using double-coil motors allows the volume occupied inside the hydraulic compartment to be reduced, for fewer calories and fewer electrical noise to be produced. According to another variant, the fuel dispenser includes a pump state detector, connected to the controller. The detector for the pump state sends a signal to the controller informing if a cavitation state or a non-priming pump state has been detected. The controller sends an instruction signal to the means of switching to switch the two-speed motor to the high speed V2 if the initial speed thereof was V1. According to another variant, the detector for the pump state is an ammeter measuring the current consumed by the two-speed motor. When the initial speed of the motor is V1, and the measured current is below a threshold value, the controller sends an instruction signal to the means of switching to switch the speed to V2. An increase of the speed of the two-speed motor to a higher power allows the cavitation phenomenon to be limited.

More generally, an increase of the speed of the two-speed motor allows the suctioning to be optimized under conditions of high pressure and temperature. This allows a fuel flowrate to be maintained at the highest possible level when one fuel dispensing line is used. When the pump is not primed, a higher rotation speed allows the pump priming to be accelerated. The pump priming time is thus also optimized. Indeed, when there is gas pocket in the duct, increasing the rotation speed of the pump allows the pump to suction up the gas pocket quickly until the fuel reaches the pump. The invention also relates to an operating method for a fuel dispenser as previously described and including a step of removing a first fuel nozzle from the hook to supply fuel into a first vehicle. According to the invention, the method includes the following steps: - switching the two-speed motor to a number Y of poles by using the means of switching to start the two-speed motor at a low rotation speed V1 in order to supply a first fuel flowrate D1 at the output of the pumping unit, - switching the two-speed motor to a number X of poles by using the means of switching to supply a rotation speed V2 that is higher than V1, when a second fuel nozzle is removed from the hook to supply fuel to a second vehicle so as to obtain a second fuel flow-rate D2 that is higher than D1, at the output of the pumping unit. The rotation speeds V1 and V2 are set and predetermined. According to one variant, the operating method includes the following steps: - measuring the current that is consumed by the two-speed motor, - switching the two-speed motor to a number X of poles by using the means of switching supplying a rotation speed V2 higher than V1 if only one fuel nozzle is removed from the hook, if the rotation speed of the two-speed motor is initially V1 and if the current that is consumed by the two-speed motor is below a threshold value, - switching the two-speed motor to a number X of poles by using the means of switching supplying a rotation speed V1 if only one fuel nozzle is removed from the hook and if the current that is consumed by the two-speed motor is greater than or equal to a threshold value.

According to one variant, the operating method of the fuel dispenser includes a silence mode wherein the rotation speed of the two-speed motor is limited to the speed V1 for a predetermined length of time T, irrespective of the current consumed by the two-speed motor.

Brief description of the drawing The characteristics of the invention will be described in further detail by referring to the enclosed non-limiting figure 1: - figure 1 schematically represents a fuel dispenser according to the invention.

Embodiments of the invention Figure 1 shows a fuel dispenser 1 including a pumping unit 2 with an electric motor 3 driving a pump 4 intended for suctioning up fuel from a fuel tank. In the present example, the electric motor 3 drives the pump 4 by means of two pulleys 12 and a transmission belt 13. The transmission between the electric motor 3 and the pump 4 can also be electrical. Pump 4 can be a rotary vane pump or a gear pump. The pumping unit 2 is connected to two fuel dispensing lines 5, wherein each line includes a flowrate measuring element 6 connected to a hose 7 equipped with a fuel nozzle 8 intended for dispensing fuel into a vehicle fuel tank. According to the invention, the electric motor 3 is a two-speed motor 3 that supplies the pump with two rotation speeds of which one low speed V1 intended for supplying a low fuel flow-rate D1 at the output of the pumping unit 2 when only one fuel nozzle 8 supplies fuel and a high speed V2 intended for supplying a high flow rate D2 at the output of the pumping unit 2 when two fuel nozzles 8 supply fuel. The two-speed motor 3 is electrically connected to a controller 9 controlling the speed of the electric motor 3 depending upon the number of active fuel nozzles 8. The controller 9 is preferentially placed inside the electronic head 14 of the fuel dispenser 1. The two-speed motor 3 is an asynchronous motor operating with a variable number of poles.

The fuel dispenser 1 includes a means of switching 10 that is controlled by the controller 9, that is used for switching from a number X of poles to a number Y of poles, wherein X is less than Y. The means of switching 10 is e. g. a contactor. Other types of electric motors with two predetermined set speeds are also possible. Preferentially, the two-speed motor 3 operates with 4 poles or with 8 poles so as to provide the set speed V2 or, respectively, V1, wherein the speed V2 is greater than the speed V1. X is thus equal to 4 and Y is equal to 8. As a variant, the two-speed motor 3 can be a 4/6 pole motor, wherein W is equal to 4 and Y is equal to 6. E. g., it is possible to use a two-speed asynchronous motor 3 that is supplied with 250 Volts. When only one fuel nozzle 8 is removed from the hook, the information is sent to the controller 9 which, in turn, sends a 6-pole operation instruction to the means of switching 10. When the two-speed motor 3 is switched to 6 poles, the rotation speed thereof is about 900 rpm. The electric motor 3 drives the pump 4 of the pumping unit 2 which is configured to deliver a fuel flowrate of about 40 I/minute. The volume of noise is then about 65 dB. When a second fuel nozzle 8 is removed from the hook, the information is sent to the controller 9 which, sends a 4-pole operation instruction to the means of switching 10. When the two-speed motor 3 is switched to 4 poles, the rotation speed thereof is about 1500 rpm. The electric motor 3 drives the pump 4 of the pumping unit 2 which is configured for delivering a fuel flowrate of about 80 I/minute, i.e. a flow-rate of 40 I/minute for each of the two fuel dispensing lines 5. The volume of noise is then about 75 dB. The consumption of electrical power by the two-speed motor 3 is reduced by about 30% for more than 80% of the time during which only one fuel nozzle 8 is active. The noise level of the filling station is also controlled by reducing the rotation speed of the two-speed motor 3.

As previously said, the two-speed motor 3 can be a 4/8-pole motor. The best known is the three-phase asynchronous motor with Dahlander coupling, named after the inventor thereof. The motor includes a 1 to 2 ratio. When switched to 4 poles, the motor supplies a rotation speed of 1,500 rpm. When switched to 8 poles, the motor supplies a rotation speed of 750 rpm. The motor can be supplied with one voltage of 230 V or of 400 V. The motor includes two windings per phase, that can be connected in parallel to obtain the maximum speed with 4 poles, or in series to obtain a speed divided by two with 8 poles. When a first fuel nozzle 8 is removed from the hook and actuated, the two speed motor 3 works with 8 poles. The rotation speed of the two-speed motor 3 is on the order of 750 rpm, corresponding to the speed V1. The pumping unit 2 can then deliver a maximum flowrate D1 of about 40 I/minute into the fuel tank of a first vehicle. When a second fuel nozzle 8 is removed from the hook and actuated, the two-speed motor 3 works with 4 poles. The rotation speed of the two-speed motor 3 is on the order of 1500 rpm, corresponding to the speed V2. The pumping unit 2 can then supply a maximum fuel flowrate D2 of about 801/minute leading to a flowrate of 40 I/minute for each fuel dispensing line 5. Each fuel tank of the two vehicles placed on both sides of the fuel dispenser 1, can be filled with a maximum fuel flowrate of 40 I/minute. The detection of the number of fuel nozzles that are removed is by known means such as a magnetic detector that is placed in the fuel nozzle holder (bag) which is attached e. g. to the fuel dispenser. A magnet that is positioned on the fuel nozzle enables the magnetic detector to detect whether or not, a fuel nozzle is present in the fuel nozzle holder. This information is sent to the controller 9. The consumption of electrical power of the two-speed step 3 is reduced by about 50% for more than 80% of the time during which only one fuel nozzle 8 is active. The two speeds V1 and V2 of rotation of the two-speed motor 3, are set and predetermined beforehand. Under high temperature and/or high-altitude conditions, fuel evaporation can occur inside the suction duct which connects the fuel storage tank and the pumping unit 2, leading to a vapor/liquid fuel mixture that is rich in fuel vapors.

The vapor/liquid fuel mixture that is rich in fuel vapors leads to a loss of flowrate, an increase of the volume of noise of pump 4, and to vibrations. These phenomena are amplified due to the overheating of pump 4 coming from the bypass circuit. Indeed, when one fuel nozzle is active, the fuel flows in a loop through the pumping unit 2, causing an overheating thereof. When the vapor pressure is too high in the vapor/liquid mixture, gas pockets form inside the suction duct, leading to the loss of priming of pump 4. To solve these problems, it is proposed to increase the speed of the two speed motor 3 to speed V2 when the initial speed is V1. An increase of the speed of the two-speed motor 3 to a higher power allows these effects to be limited. More generally, an increase of the speed of the two-speed motor 3 allows the suctioning to be optimized under conditions of high pressure and temperature. This allows a fuel flowrate to be maintained at the highest possible level when one fuel dispensing line 5 is used. The increase of the rotation speed of pump 4 has the effect of reducing the phenomenon of cavitation. The gas rich phase is suctioned up quicker. When pump 4 is not primed, a higher rotation speed is thus used for a better priming of pump 4. When a gas pocket is present inside the duct, a higher rotation speed is used to increase the suction speed to remove the gas pocket. The fuel dispenser 1 includes a pump state detector 11 connected to the controller 9. The detector 11 for the pump state detects if the pump is faced with a cavitation problem or if same is not primed when started. The detector 11 for the pump state, sends a signal to the controller 9 informing if a cavitation state or a non-priming pump state 4 has been detected. Generally, the cavitation state also includes the presence of gas pockets. When one such a state is detected, the controller 9 sends an instruction signal to the means of switching 10 to switch the two-speed motor 3 to the high speed V2 if the initial speed thereof was V1. The detector 11 for the pump state measures the current consumed by the two-speed motor 3. When the initial speed of the motor is V1, and that the measured current is below a threshold value, the controller 9 sends an instruction signal to the means of switching 10 to switch the speed to V2.

The detector 11 for the pump state can be an ammeter. The detector 11 for the pump state can include an ammeter associated with a voltmeter for measuring the electrical power that is consumed. The threshold value for the current can correspond to a mean value of the current that is measured when a pumping unit 2 works normally, without cavitation and with a primed pump 4. When the pump 4 works normally, same consumes more electrical power than when same cavitates or when same is not primed. The current that is consumed is thus higher under normal operation. Indeed, when the pump 4 cavitates, the concentration of gas in the fuel is higher, leading to a lower pressure. The pump 4 supplies less force to suction up a gas instead of a liquid. Similarly, when the pump 4 is not primed, same suctions up gas and supplies less force for turning. The detector 11 for the pump state can be, as a variant, a spectrum analyzer that analyzes the spectrum of the power or of the current that is consumed by the two-speed motor 3. The spectrum that is measured is compared with a reference spectrum corresponding to normal operation, without cavitation and with the pump 4 that is primed. The detector 11 for the pump state can be, in a variant, a pressure detector or a sound detector that detects vibration frequencies that are characteristic of cavitation. The cavitation phenomenon indeed leads to additional vibrations. The speed V2 is maintained as long as the measured current does not rise above the threshold value. When the speed rises above this value, the controller 9 sends an instruction signal to the means of switching 10 to switch the two-speed motor 3 to 8 poles, supplying the speed V1 if only one fuel nozzle 8 is active. For about 80% of the operating time of a fuel dispenser 1, only one fuel nozzle 8 is active. Limiting the speed of the pump to V1 during all this time, strongly limits the cavitation phenomenon and limits the noise, while reducing the electrical consumption of the motor. An operating method of the fuel dispenser 1, is described below. When a fuel nozzle 8 is removed from the hook, the two-speed motor 3 starts at the low speed V1. The motor thus operates with 8 poles or with 6 poles, depending upon the choice of the two-speed motor 3.

Current measurement by the detector 11 for the pump state is used to check whether the pump 4 is primed or not. If the pump 4 is not primed, the controller 9 sends an instruction signal to the means of switching 10 to switch the motor to 4 poles (speed V2) until priming. This is used to accelerate the priming operation and to keep a dry negative pressure as high as possible. The operating method includes a silence mode wherein the rotation speed of the two-speed motor 3 is limited to the speed V1 for a predetermined length of time T, irrespective of the current consumed by the two-speed motor 3. This length of time corresponds to hours corresponding to night-time in the center of the town, when the noise of the fuel dispenser 1 has to be reduced. In a variant, the length of time T can be programmed during summertime during periods of intense heat during daytime, limiting the risk of cavitation. The length of time T can be programmed directly in the fuel dispenser 1 or in the central control station of the filling station. The silence mode is maintained even if both fuel nozzles 8 are removed from the hooks. If the silence mode is not active, the speed V2 is maintained after priming when the 2 fuel nozzles 8 are active. If the pump 4 is primed at the start and if one fuel nozzle is active, the speed is maintained at V1. Irrespective of the number of fuel nozzles 8 removed from the hook, if the detection of the cavitation mode is triggered (low current that is measured during the operation phase of the motor), switching to 4 poles (speed V2) is automatic. Thus, the invention is used to reduce the consumption of electrical power of the motor on the order of 30% if a 4/6 pole motor is used or by 50% if a 4/8 pole motor is used for 80% of the operating time of the fuel dispenser 1. By comparison, using a frequency controller allows the electrical power consumption to be reduced, at best, by 10%, while being more expensive. It is also possible to call upon the bypass circuit less, thus reducing fuel overheating. The noise level of the filling station is also controlled by a reduction of the speed at the pump, and hence of the maximum fuel flowrate during critical times (night-time in the center of the town or intense heat).

The pump 4 priming time is also optimized. The maximum flowrate of the filling station stays optimum under the permissible conditions (day-time or normal temperature).

Claims

1. Fuel dispenser (1) including a pumping unit (2) with an electric motor (3) driving a pump (4), intended for suctioning up fuel from a fuel tank, wherein the pumping unit (2) is connected to two fuel dispensing lines (5) each having a flow rate measuring element (6) that is connected to a hose (7) equipped with a fuel nozzle (8), intended for supplying fuel into a vehicle fuel tank, characterized in that the electric motor (3) is a motor with two predetermined speeds (3), supplying the pump (4) with two rotation speeds of which a low speed V1 intended for supplying a low fuel flow-rate D1 at the output of the pumping unit (2) when one fuel nozzle (8) supplies fuel, and a high speed V2 intended for supplying a high fuel flow-rate D2 at the output of the pumping unit (2) when two fuel nozzles (8) supply fuel, wherein the two-speed motor (3) is electrically connected to a controller (9) controlling the speed of the electric motor (3) depending upon the number of active fuel nozzles (8), and in that the two-speed motor (3) is an asynchronous motor working a variable number of poles, wherein the fuel dispenser (1) includes a means of switching (10) that is controlled by the controller (9) for switching from a number of X poles to a number of Y poles.

2. Fuel dispenser (1) according to claim 1, characterized in that the two speed motor (3) operates with 4 poles or with 8 poles so as to obtain the set speed V2 or V1 respectively.

3. Fuel dispenser (1) according to claim 1 or 2, characterized in that same includes a detector (11) for the pump state, that is connected to a controller (9), said detector (11) for the pump state sending a signal to the controller (9) informing thereof whether a state of non-priming of the pump (4) is detected, wherein said controller (9) sends an instruction signal to the means of switching (10) to switch the two-step motor (3) to the high speed V2 if the initial speed thereof was V1.

4. Fuel dispenser according to claim 3, characterized in that the detector (11) for the pump state is an ammeter that measures the current consumed by the two-step motor (3), when the initial speed of the motor is V1 and the measured current is below a threshold value, wherein the controller (9) sends an instruction signal to the means of switching (10) to switch the speed to V2.

5. Operating method for a fuel dispenser (1) as defined by any of the claims 1 to 4, wherein said fuel dispenser (1) includes a pumping unit (2) with a two speed motor (3) driving a pump (4) intended for suctioning up fuel from a fuel tank, wherein the pumping unit (2) is connected to two fuel dispensing lines (5) each having a flow-rate measuring element (6) connected with a hose (7) equipped with a fuel nozzle (8) intended for supplying fuel to a vehicle fuel tank, wherein said two step motor (3) is an asynchronous variable pole motor (1) including means of switching (10) controlled by the controller (9) for switching from a number X of poles to a number Y of poles, where X is less than Y, said method including a step of removing from the hook, a first nozzle (8) to supply fuel to a first vehicle, characterized in that the method includes the following steps: - switching the two-speed motor (3) to a number Y of poles by using the means of switching (10) to start the two-speed motor (3) at a low rotation speed V1 in order to supply a first fuel flow-rate D1 at the output of the pumping unit (2), - switching the two-speed motor (3) to a number X of poles by using the means of switching (10) to supply a rotation speed V2 that is higher than V1, when a second fuel nozzle (8) is removed from the hook to supply fuel to a second vehicle so as to obtain a second fuel flow-rate D2 that is higher than D1, at the output of the pumping unit (2).

6. Operating method for a fuel dispenser (1) according to claim 5, characterized in that the rotation speeds V1 and V2 are set and predetermined.

7. Operating method for a fuel dispenser (1) according to any of claims 5 or 6, characterized in that same includes the following steps: - measuring the current that is consumed by the two-step motor (3), - switching the two-speed motor (3) to a number X of poles by using the means of switching (10) supplying a rotation speed V2 higher than V1 if only one fuel nozzle (8) is removed from the hook, if the rotation speed of the two-speed motor (3) is initially V1 and of the current that is consumed by the two-speed motor (3) is below a threshold value,

- switching the two-speed motor (3) to a number X of poles by using the means of switching (10) supplying a rotation speed V1 if only one fuel nozzle (8) is removed from the hook and if the current that is consumed by the two-speed motor (3) is greater than or equal to a threshold value.

8. Operating method for a fuel dispenser (1) according to any of claims 5 to 7, characterized in that same includes a silence mode wherein the rotation speed of the two-speed motor (3) is limited to the speed V1 for a predetermined length of time T, irrespective of the current consumed by the two-speed motor (3).

FIGURE 1