Patent Description:
<CIT> discloses a device for fuel supply of internal-combustion engine.

<CIT> discloses a fuel supply system and tank installation for an internal combustion engine.

<CIT> discloses a fuel container for a motor vehicle.

<CIT> discloses a system for a fuel system in an engine having a fuel tank. The fuel tank includes a first compartment and a second compartment, wherein a reservoir is located within the first compartment. Fuel within the first compartment may be delivered to the reservoir via a first jet pump, and fuel within the second compartment may be delivered to the reservoir via a second jet pump.

The module pot constitutes a volume which is separated by a pot wall from the remaining interior volume of the tank, so that fuel delivered to the engine by the fuel pump located in the module pot must be replenished from the remaining interior volume of the tank. This is done, for example, by the use of a suction jet pump which is operated by a partial flow diverted from a fuel line leading to the exterior of the tank. In the case of a saddle tank having two chambers which are partially separated from each other by the saddle, wherein the module pot is located in the first of the two chambers, fuel must be transported by a pump, usually a suction jet pump, from the second chamber to the first chamber when the fill level in the second chamber falls below the height of the saddle separating the two chambers from each other. Also in the case of a saddle tank fuel is transported by a further pump from the first chamber into the module pot. It is customary to operate the pump or the multiple pumps continuously, even if this would not be necessary by system demands, such as the fill levels in the first and second chamber and the module pot. The continuous operation unnecessarily wastes energy.

The present disclosure provides a fuel delivery assembly and method that optimizes the energy usage for the operation of the pumps in the fuel tank.

For the solution of this object the combinations of features of claims <NUM> and <NUM> are proposed. Advantageous embodiments and further developments result from the dependent claims.

The present disclosure teaches that by monitoring the relevant parameters an intelligent pump control can be implemented. According to the present disclosure, a sensor device is used to detect a predetermined minimum fill level in the module pot, wherein the pump disposed in the first chamber is activated when the minimum fill level is reached and is deactivated after a predetermined time interval or when a predetermined higher fill level in the module pot is reached. In particular, the sensor device may comprise a first sensor with which a predetermined maximum fill level in the module pot, at which the first pump is deactivated, is detected, and a second sensor with which the predetermined minimum fill level in the module pot is detected.

According to a preferred embodiment of the present disclosure the fuel tank is a saddle tank and has a second chamber with at least one second pump for delivering fuel from the second chamber to the first chamber disposed therein, and to further reduce the energy usage a third sensor is disposed in the second chamber for detecting a predetermined minimum fill level in this chamber, wherein the pump disposed in the second chamber is deactivated in response to the third sensor when the predetermined minimum fill level is reached, wherein the second pump is arranged to deliver fuel from the second chamber into the first chamber but not into the module pot disposed therein, and wherein the third sensor in the second chamber is connected to an electronic control unit such that when a minimum fuel level in the second chamber is detected the second pump is shut off.

Preferably the first and/or the second pump is a suction jet pump and a partial flow is diverted from the fuel pump located in the module pot to operate the first and/or second suction jet pump.

Since the suction jet pumps are operated by a partial flow diverted from the fuel pump, the activation and deactivation of the suction jet pumps may advantageously be effected by controlling at least one valve disposed in the feed line to the first and/or second suction jet pump. According to a further development of the present disclosure a first valve is located in a feed line for the operation of the first and/or second suction jet pump, which opens to allow the operation of at least the first suction jet pump when the sensor device is the module pot detects the predetermined minimum fill level, and which closes to stop the operation of at least the first suction jet pump when the sensor device in the module pot detects the predetermined maximum fill level. Correspondingly, a second valve may be located in the feed line for the operation of the first and/or second suction jet pump, which second valve closes to stop the operation of the second suction jet pump when the third sensor detects the predetermined minimum fill level in the second chamber.

In the following the present disclosure will be described with reference to embodiments schematically shown in the drawing, in which.

The saddle tank <NUM> schematically shown in <FIG> comprises a first chamber <NUM> and a second chamber <NUM>, the volumes of which are partially separated from each other by a saddle <NUM>. A module pot <NUM> is disposed in the first chamber <NUM>, which contains a fuel pump <NUM> and which forms a reservoir for fuel. The module pot <NUM> further contains a first sensor <NUM> for detecting a predetermined maximum fill level and a second sensor <NUM> for detecting a predetermined minimum fill level. A fuel line <NUM> leads from the fuel pump <NUM> to a motor (not shown), and a feed line <NUM> for the operation of suction jet pumps is diverted from the fuel line <NUM>. A first suction jet pump <NUM> is located in the first chamber <NUM> and delivers fuel from this chamber to the module pot <NUM>. A second suction jet pump <NUM> is located in the second chamber <NUM> and delivers fuel from this chamber to the first chamber <NUM>. A first valve <NUM> and a second valve <NUM> are located in the feed line <NUM>. The first valve <NUM> controls the flow to the two suction jet pumps <NUM>, <NUM>, while the second valve <NUM> controls the flow only to the second suction jet pump <NUM>. Further, a third sensor <NUM> for detecting a predetermined minimum fill level or for detecting a state in which the suction side of the second suction jet pump cannot pick up fuel due, for example, to lateral acceleration or tilting of the saddle tank is located in the second chamber <NUM>. Further, there is provided an electronic control unit (not shown) which receives the various sensor signals and controls the valves <NUM>, <NUM> to open and shut off, as will be described below with reference to an operational diagram.

The operation of the delivery control to optimize the energy usage will be described with reference to the diagram of <FIG>, which traces the fill levels in the module pot <NUM> and in the second chamber <NUM> as well as the operating cycles of the suction jet pumps <NUM>, <NUM> as a function of time t.

In the upper portion of the diagram a saddle height <NUM> and maximum and minimum fill levels <NUM>, <NUM> corresponding to the first and second sensor <NUM>, <NUM> are shown as horizontal lines. The progress of the fill level in the module pot <NUM> as the total fuel content of the saddle tank <NUM> is gradually consumed is represented by the line <NUM>. When the module pot <NUM> is fully filled while the fill level in the saddle tank <NUM> exceeds the upwardly open module pot <NUM> as well as the saddle <NUM>, the operation of neither the first nor the second suction jet pump is necessary, and the valves <NUM>, <NUM> are shut off.

At the point in time A the fill level in the saddle tank <NUM> falls below the height of the saddle <NUM>. The fill level in the second chamber <NUM>, the fuel content of which now cannot flow freely into the first chamber <NUM> anymore, is represented by the line <NUM>. At the point in time B the fill level in the module pot <NUM> reaches the level of the first sensor <NUM> and then progressively falls to the level of the second sensor <NUM> at the point in time C. At this point in time C the electronic control unit opens the valves <NUM>, <NUM> and both suction jet pumps <NUM>, <NUM> begin to operate, so that on the one hand fuel is delivered into the module pot <NUM> by means of the first suction jet pump <NUM>, and on the other hand fuel is delivered from the second chamber <NUM> to the first chamber <NUM>. The operation of the suction jet pumps <NUM> and <NUM> is represented by shaded blocks <NUM> and <NUM>, respectively. Both suction jet pumps continue to operate until a fill level at the level of the first sensor <NUM> is reached in the module pot <NUM> at the point in time D. The valves <NUM>, <NUM> are then shut off and the suction jet pumps are made inoperable. This opening and shutting-off of the valves <NUM>, <NUM> in response to the sensors <NUM>, <NUM> continues in the described manner until the point in time E is reached. At the point in time E the third sensor <NUM> in the second chamber <NUM> detects that the minimum predetermined fill level has been reached. A further operation of the second suction jet pump <NUM> would be ineffective. The electronic control unit therefore shuts off the second valve <NUM> in response to the third sensor <NUM> signal until the next refueling event.

From the point in time E on, fuel is present only in the first chamber <NUM> and in the module pot <NUM>. The operation of the first suction jet pump <NUM> continues as described above in response to the sensors <NUM>, <NUM>, until the fuel content of the first chamber <NUM> has been exhausted. During this time the electronic control unit operates only the first valve <NUM> to open and shut off. Finally, only the reserve volume of fuel in the module pot <NUM> remains, until the next refueling event.

The control and operation of the suction jet pumps <NUM>, <NUM> in response to the three sensors <NUM>, <NUM>, <NUM> as described above effectively minimizes the operational energy provided by the fuel pump <NUM>.

<FIG> shows a single chamber tank <NUM> comprising a module pot <NUM> having a fuel pump <NUM> disposed therein and a fuel line <NUM> leading from the fuel pump to a vehicle engine, from which fuel line a feed line <NUM> for the operation of a suction jet pump <NUM> is diverted. In the module pot <NUM> a sensor device <NUM> designed as a piezo fill level meter is provided as an alternative to the two sensors <NUM>, <NUM> shown in <FIG>, by means of which predetermined minimum and maximum fill levels are detected, in response to which the suction jet pump <NUM> is activated or deactivated. When reaching the predetermined minimum fill level an electronic control unit (not shown), in which the predetermined operating parameters are also stored, opens a valve <NUM> located in the feed line <NUM> to operate the suction jet pump <NUM>, which then delivers fuel to the module pot <NUM> until the predetermined maximum fill level is reached. The valve <NUM> is then shut off by means of the electronic control unit and the delivery of fuel to the module pot is stopped, until the minimum fill level is reached once again. It is also possible to monitor only the minimum fill level in the module pot <NUM> and to operate the suction jet pump <NUM> for a predetermined time interval when reaching this minimum fill level. When the delivery rate of the suction jet pump <NUM> is known, the time until the desired maximum fill level in the module pot <NUM> is reached can be calculated.

Claim 1:
A method for delivering fuel in a fuel tank (<NUM>), wherein the fuel tank (<NUM>) is a saddle tank having at least a first chamber (<NUM>) and a second chamber (<NUM>), the first chamber (<NUM>) having a module pot (<NUM>) disposed therein and at least a first pump (<NUM>) adapted to deliver fuel from the first chamber (<NUM>) to the module pot (<NUM>), and wherein a fuel pump (<NUM>) for delivering fuel to an engine is disposed within the module pot (<NUM>), the second chamber (<NUM>) having at least one second pump (<NUM>) disposed therein for delivering fuel from the second chamber (<NUM>) to the first chamber (<NUM>), wherein a sensor device (<NUM>, <NUM>) is disposed in the module pot (<NUM>) to detect a predetermined minimum fill level in the module pot (<NUM>), wherein the pump (<NUM>) disposed in the first chamber (<NUM>) is activated when the sensor device (<NUM>, <NUM>) detects the minimum fill level is reached and is deactivated after a predetermined time interval or when a predetermined higher fill level in the module pot (<NUM>) is reached, and a third sensor (<NUM>) is disposed in the second chamber (<NUM>) for detecting a predetermined minimum fill level in the second chamber (<NUM>), wherein the second pump (<NUM>) disposed in the second chamber (<NUM>) is deactivated in response to the third sensor (<NUM>) detecting when the predetermined minimum fill level is reached, characterized in that the second pump (<NUM>) is arranged to deliver fuel from the second chamber (<NUM>) into the first chamber (<NUM>) but not into the module pot (<NUM>) disposed therein, and that the third sensor (<NUM>) in the second chamber (<NUM>) is connected to an electronic control unit such that when a minimum fuel level in the second chamber (<NUM>) is detected the second pump (<NUM>) is shut off .