The invention relates to a tank for storing demineralized water on board of a vehicle and to system for injecting demineralized water into an air intake upstream of a combustion chamber or directly in the combustion chamber of a vehicle. It is known to inject water into an air intake upstream of a combustion chamber or directly in the combustion chamber, when the load of the engine of the vehicle is high. By injecting water in the air stream, the air is cooled down, resulting in a higher density and hence more air per volume unit, enhancing the combustion. In that manner more power is obtained, i.e. the performance is boosted.

The demineralized water for injection needs to be stored on-board the vehicle, and in view of the limited space on-board a vehicle it is desirable to have a compact water storage and injection system. Moreover, it is also desirable to have liquid demineralized water at disposal when needed for injection in the combustion chamber of a vehicle.

The present invention aims to solve these problems by providing a tank for storing demineralized water on board of a vehicle and a system for injecting demineralized water into an air intake upstream of a combustion chamber or directly in the combustion chamber of a vehicle. A first object of the invention is to provide a tank for storing demineralized water on board of a vehicle which is capable of delivering liquid demineralized water. More in particular, it is an object of embodiments of the invention to provide a vehicle system which can inject demineralized water into an air intake upstream of a combustion chamber or directly in the combustion chamber of a vehicle. According to an aspect of the invention there is provided a tank for storing demineralized water on board of a vehicle comprising a first heater and a delivery module comprising a pump unit and a second heater. A tank comprising a first heater and a delivery module comprising a pump unit and a second heater leads to a greater thawing efficiency regarding the heating of the demineralized water. The constraints being different depending on the zone of the tank to be heated, particularly in terms of cumberness due to the presence of accessories, the use of two heaters allows an improved heating of the demineralized water contained in the tank.

The delivery module comprises a pump unit and a second heater, the delivery module being provided to inject the demineralized water into an injection line and being connected to said line. Said delivery module may be divided in two zones a dry zone and a wet zone. The second heater may be located in the dry zone and/or the wet zone. Preferably, the second heater is located in the wet zone. By the expression "wet zone", we intend to mean a zone of the delivery module containing demineralized water in fluidic connection with the tank. By the expression "dry zone", we intend to mean a zone of the delivery module that doesn't contain demineralized water. By the expression "demineralized water", we intend to mean a water solution having a conductivity lower than or equal to 50 μ8Λ:ι at 20°C.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention comprises a first heater selected from the group consisting of an electric tubular heater and a fluid tubular heater, preferably the first heater is an electric tubular heater.

The electric tubular heater and the fluid tubular heater have a high power density compared to other heaters leading to increased performances for lower temperature in cold start for thawing demineralized water. The tubular heaters are rigid offering a better ice stresses resistance. They also allow a use in air with no reduce power density compared to other heaters.

By the expression "electric tubular heater", we intend to mean that an electrical device that converts electric current to heat, said electrical device having a tubular shape.

By the expression "fluid tubular heater, we intend to mean a tubing for transporting a heat exchange fluid, e.g. engine coolant.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention is such that the second heater is selected from the group consisting of an electric flexible heater and a PTC heater.

The PTC (i. e., Positive Temperature Coefficient) heater reduces the number of operation during mounting, decreases sealing interface issues with electrical connector to power the PTC and the temperature of the second heater in air is self-controlled and does not need any power-density reduction to avoid degradation at average power. The electric flexible heater comprises at least a flexible part. The electric flexible heater comprises one or more resistive track(s) affixed to a film or placed between two films (that is to say two substantially flat supports, the material and thickness of which are such that they are flexible). This film is preferably made of a plastic (although any other insulating material may be suitable) and, in particular, is based on an elastomer

The resistive tracks may be based on metal, carbon, etc. or even a combination of such conductive materials. They are generally sandwiched between two flexible films. They are applied (for example, by jet printing techniques) onto a flexible film and then covered with another flexible film or overmoulded using an insulating (preferably elastomeric) material. The two films are then firmly attached together (for example, by vulcanization) to ensure sealing around the resistive tracks. These tracks are preferably connected in parallel so that if one of the tracks is damaged, it does not impede the operation of the other tracks.

The flexible films may be made of silicone resin, polyolefin (polyethylene or polypropylene), thermoplastic elastomer (or TPE), polyester, polyimide. The flexible films may also comprise several superposed layers of resistors (resistive tracks). They may also comprise a glass-fibre coating to improve their mechanical strength.

Stainless steel resistive tracks sandwiched between two silicone resin films, one of which is covered with a network of glass fibres, give good results in the context of the invention. Most particularly preferably, it comprises several excrescences or tentacles which are positioned uniformly in the tank so as to be able to heat its contents completely and as homogeneously as possible, even in the nooks distant from the body of the heater from which the tentacles extend. In this variant, the body of the heater may comprise a resistive track and tentacles, at least one other resistive track, these tracks preferably being connected in parallel to a power supply terminal.

The term "body" is understood to mean a part of the heater where the tentacles start from or where the resistive tracks start from and arrive at. The abovementioned tentacles may be obtained in any known manner.

By the expression "flexible heater", we intend to mean that the heater has at least one flexible part. The qualifier "flexible" is in fact understood to mean "easily deformable", this generally being in a reversible manner. Generally, this corresponds to a flexural rigidity (defined as being equal to (Eh) ³ /((12 (l-υ ² )) where E is the Young's modulus of the flexible pat measured according to the ASTDM D790-03 standard, h is its thickness and υ is the Poisson's ratio of its constituent by material) below 4000 N.m.; preferably the flexural rigidity of the flexible part is less than or equal to 1000 N.m, more preferably less than or equal to 100 N.m, most preferably less than or equal to 10 N.m, the most preferably less than or equal to 1 N.m.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention comprises a first heater and a delivery module comprising a pump unit and an electric flexible heater.

Using a second heater which is an electric flexible heater has the advantage that immediate heater power is available reducing the start-up time at cold temperatures. The first heater may be a fluid or an electric tubular heater. The fluid tubular heater may be used for circulating engine coolant. The heater power of tubing will depend on engine heat up speed, and without the electrical heater the start-up time would be much longer. By suitably combining a second heater which is an electrical heater with a first heat which is a fluid tubular heater for engine coolant an optimal heating can be achieved fulfilling the start-up requirements whilst at the same time using heat from the engine coolant once the engine is heated up sufficiently. The first heater may also be an electric tubular heater.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention is such that the electric flexible heater is located closer to the delivery module than the first heater.

The flexibility of the electric flexible heater permits to fit it in delivery module near the pump in order to thaw fluid even in narrow areas where clearance becomes challenging. By the expression "the electric flexible heater is located closer to the delivery module than the first heater", we intend to mean that the minimal distance between the delivery module and the electric flexible heater is lower than the minimal distance between the first heater and the delivery module. According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention is such that the electric flexible heater is located partly or totally in the delivery module.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention is such that the first heater is located at the bottom wall of the tank.

A first heater located at bottom wall of the tank may be immersed as much as possible in any situation and inclination of the vehicle. Moreover, a location at the bottom of the tank permits an insertion of said first heater into the tank which is simpler. Finally, in the case of an electric tubular heater, it also simplifies the electrical connection and reduces the distance to an ECU; being always immersed, it allows applying a greater power density.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention is such that the first heater is affixed on a sidewall or on the bottom wall of the tank.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention comprises a third heater, preferably said third heater is a supplemental tubular heater. The use of a plurality of heater enables different power density and versatility; especially if decoupling of the heaters is considered with a strategy attached to meet the thawing goals. Depending on capability of power output and design of the technology, it is possible to meet the total power requirement.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention is such that the first heater is located closer to the delivery module than the third heater. The advantage relates to the fact that at least one heater may be dedicated to the thawing of peculiar/critical areas/components such as the module, especially if power available is reduced during a period of time.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention comprises a UV light decontamination device configured for decontaminating the water stored in the tank by emitting UV light. Preferably the UV light decontamination device is arranged in the tank. Such an arrangement leads to a gain in volume reduction of the overall system, increased integration and reduced number of interfaces and fluid circulation lines. Moreover, it reduces the number of holes in the tank shell. More preferably, the UV light decontamination device is located in the delivery module. This location leads to maximizing integration, to reducing the number of holes in the tank shell.

According to a preferred embodiment, the tank for storing demineralized water on board of a vehicle according to the invention is such that at least a wall of the tank comprises an antimicrobial agent.

A second aspect of the present invention related to a method for thawing ice. The method for thawing ice contained in a tank for storing demineralized water on board of a vehicle according to the invention comprises a step of thawing ice of demineralized by using a first heater and/or thawing ice of demineralized water by using a second heater. Said method has a good flexibility in the management of the electric power required.

A third aspect of the present invention related to a vehicle system for injecting demineralized water, said vehicle system comprising:

A tank (500) for storing demineralized water according to the invention, the tank comprising a first heater (200 ) and a delivery module (100), the delivery module (100) comprising a pump unit (110) and a second heater (201), A feed line (350), that connects the pump unit (110) to an injector (310),

A combustion chamber (400) connected to an air intake (200) and the injector (310),

The function of the pump being to pump water from the tank the combustion chamber (400) or anywhere as long as the air provided to the combustion chamber (400) is cooled by the injected water.

The vehicle system may further comprise a controller for controlling the electrical heaters e.g. in function of the engine temperature or in function of the time during which the engine has been running. In that manner the heating can be adequately controlled and optimized.

The accompanying drawings are used to illustrate presently preferred non-limiting exemplary embodiments of devices of the present invention. The above and other advantages of the features and objects of the invention will become more apparent and the invention will be better understood from the following detailed description when read in conjunction with the accompanying drawings, in which:

Figure 1 illustrates schematically a side elevation of an exemplary embodiment of a tank for storing demineralized water on board of a vehicle according to the invention;

Figure 2 illustrates a partly broken away top view of a first variant of an exemplary embodiment of a tank for storing demineralized water on board of a vehicle according to the invention.

Figure 3 illustrates a partly broken away top view of a second variant of an exemplary embodiment of a tank according to the invention. Figure 4 shows a side planar view of a detailed structure of a delivery module adapted for mounting in the tank according to the invention

Figure 5 shows a side view of a variant of the structure of a delivery module adapted for mounting in the tank according to the invention Figure 6 shows a side view of another variant of the structure of a delivery module adapted for mounting in the tank according to the invention

Figure 7 illustrates a cross section side view a third variant of an exemplary embodiment of a tank according to the invention.

Figure 8 illustrates a cross section side view of a vehicle system for injecting demineralized water

Figure 1 illustrates an exemplary embodiment of the tank 500 for storing demineralized water on board of a vehicle according to the invention. The pump unit 110 is arranged in a delivery module 100, the pump unit 110 may comprise a gear pump. The delivery module 100 is mounted in an opening 550 in the tank 500. The tank 500 has a bottom wall 510, a top wall 520 and a sidewall 530 connecting the bottom wall 510 with the top wall 520. In the illustrated embodiment the opening 550 is arranged in the bottom wall 510, wherein, in the mounted position of the tank 500, the bottom wall 510 corresponds with the lowest face of the tank 500. The tank 500 comprises a first heater 200 and the delivery module 100 comprises a second heater 201 for heating the demineralized water in tank 500. The delivery module 100 may further comprise any one or more of the following components (not shown): a level sensor for sensing the level of the demineralized water in tank 500); a quality sensor for measuring the quality of the demineralized in tank 500; a filter, optionally integrated in pump unit 110 for filtering the demineralized water before it is transported through feed line 350; a UV light decontamination device configured for decontaminating the demineralized water in tank 500; a controller for controlling any one or more of the components of the module 100. The tank according to the invention further comprises a return line 360 integrated in the module 100. The return line 360 connects the feed line 350 with the interior of the tank 500. The return line 360 is connected to the feed line 350 in the delivery module 100. The return line 360 comprises a check valve 160 in order to regulate the return flow. The pump unit 110 has an inlet 111 for receiving the demineralized from the tank 500 and an outlet 112 connected to the feed line 350. It is noted that figure 1 is a schematic drawing and that the inlet 111 is preferably located as low as possible in the tank 500, and more generally below the minimum filling level. The pump unit 110 may comprise e.g. a gear pump. By the expression "quality sensor", we intend to mean a sensor determining the physical properties of the demineralized water such as the conductivity, the emissivity or the dielectric constant or an ultrasound measuring system comprising an ultrasound emitter, a reflector and an ultrasound receiver.

Figure 2 illustrates an exemplary embodiment of the tank 500 for storing demineralized water on board of a vehicle according to the invention. The pump unit (not shown) is arranged in a delivery module 100. The delivery module 100 is mounted in an opening in the tank 500. In the illustrated embodiment the opening is arranged in the bottom wall 510, wherein, in the mounted position of the tank 500, the bottom wall 510 corresponds with the lowest face of the tank 500. The tank comprises a first heater 200 and the delivery module 100 comprises a second heater (not shown) for heating the demineralized water in tank 500. The delivery module 100 may further comprise any one or more of the following components (not shown): a level sensor for sensing the level of the demineralized water in tank 500; a quality sensor for measuring the quality of the demineralized water in tank 500; a filter, optionally integrated in pump unit for filtering the demineralized water before it is transported through the feed line; a UV light decontamination device configured for decontaminating the demineralized water in tank 500; a controller for controlling any one or more of the components of the delivery module 100. Figure 3 shows a detailed view of an exemplary embodiment of the tank 500 for storing demineralized water on board of a vehicle according to the invention. The delivery module 100 comprises a compartment 105, and a pump unit 110 arranged in the compartment 105. The pump unit 110 is arranged in a delivery module 100, the pump unit 110 may comprise a gear pump. The delivery module 100 is mounted in an opening in the tank 500. In the illustrated embodiment the opening is arranged in the bottom wall 510, wherein, in the mounted position of the tank 500, the bottom wall 510 corresponds with the lowest face of the tank 500. The tank comprises a first heater 200 and the delivery module 100 comprises a second heater 201 for heating the demineralized water in tank 500. The first heater 200 is a tubular electric heater affixed in a sidewall of the tank 500. The second heater 201 is a flexible electric heater 120 with flexible tentacles 121 extending in the tank 500 trough opening in the compartment 105. The delivery module 100 may further comprise any one or more of the following components (not shown): a level sensor for sensing the level of the demineralized water in tank 500; a quality sensor for measuring the quality of the demineralized water in tank 500; a filter, optionally integrated in the pump unit 110 for filtering the demineralized water before it is transported through feed line; a UV light decontamination device configured for decontaminating the demineralized water in tank 500; a controller for controlling any one or more of the components of the module 100.

Figure 4 illustrates a more detailed embodiment of a delivery module 100 adapted for mounting in an opening 550 of bottom wall 510 of tank for storing demineralized water 500 according to the invention. The delivery module 100 comprises a cylindrical compartment 105, and a pump unit 110 arranged in cylindrical compartment 105. Pump unit 110 comprises a gear pump 113 and a motor 114 (e.g. a BLDC motor). The pump unit 110 has an inlet 111 at the lower end of a cylindrical housing 115 of pump unit 110. In this embodiment a filter 150 is integrated in pump unit 110. The outlet 112 of pump unit 110 is located at a lower end of pump unit 110, below gear pump 113. Outlet 112 is connected to a first portion of feed line 350. This portion of feed line 350 is connected to a return line 360 including a check valve 160. Return line 360 is integrated in module 100 and is located partially below pump unit 110. The outlet of return line 360 is located adjacent to pump unit 110, and returns the demineralized water into tank 500. A second heater 120 is provided adjacent cylindrical compartment 105 of the delivery module 100. The second heater 120 is preferably an electric flexible heater. In the illustrated embodiment the second heater is a flexible electrical heater 120 with flexible tentacles 121 extending in the tank 500. However, it is also possible to provide non-flexible electrical heating elements (not shown), e.g. PTC heating elements, adjacent to cylindrical compartment 115, e.g. attached to the inside or the outside of this cylindrical compartment. In the illustrated embodiment the cylindrical housing 115 of the pump unit 110 contains a separation wall 116 dividing the housing in an upper compartment for the motor 114 and a lower compartment for the gear pump 113. Demineralized water enters the lower compartment of the cylindrical housing 115 at the bottom thereof, see the inlet 111, passes through the filter 150 and leaves the lower compartment at the outlet 112.

Figure 5 illustrates another detailed embodiment of a delivery module 100 adapted for mounting in an opening of bottom wall of a tank for storing demineralized according to the invention in a similar manner as shown in figure 3. The module 100 comprises a compartment 105, and a pump unit 110 arranged in the compartment 105. The pump unit 110 may comprise a gear pump and a motor. The pump unit 110 may have an inlet (not visible) at the lower end of the pump unit 110. The outlet (not visible) of the pump unit 110 may be located at a lower end of the pump unit 110. The delivery module 100 may comprise a portion of feed line and a return line including a check valve. A second heater 120 is provided on the delivery module 100, and may be attached to the compartment 105. The second heater 201 is preferably an electric heater. In the illustrated embodiment the heater is a flexible electric heater 120 with flexible tentacles 121 extending in the tank. However, it is also possible to provide non-flexible electrical heating elements (not shown), e.g. PTC heating elements, adjacent to compartment, e.g. attached to the inside or the outside of this compartment 105. The compartment 105 has an outer wall with a shape which is such that an inner volume is created for receiving the pump unit 110, and a small outer volume 106 for receiving a level sensor 130. The outer wall of compartment 105 is shaped to surround partially level sensor 130. In that manner damage to the level sensor is avoided.

Figure 6 illustrates an embodiment of a delivery module 100 not shown on the figure with a first heater 200, said first heater being a tubular heater 170 and a second heater 201, said second heater 201 being a flexible electric heater (120). In this embodiment the flexible electrical heater 120 is provided with a number of openings. Components, such as pump unit 110, a level sensor 130, a quality sensor 140, may be mounted on the delivery module 100 and may protrude through said openings. The first heat 200 being a tubular heater 170 may have various shapes. Preferably, the tubular heater 170 has a shape which is such that the delivery module 100 can be mounted in an opening in the tank from the outside; in other words the tubular heater 170 should fit through the opening 550.

Figure 7 illustrates a further embodiment with first heater 200 being a tubular heater 170 and an electrical heater 120. The first heater 200 which is a tubular heater 170 is mounted in the sidewall 530 of the tank 500, and the delivery module 100 carries a second heater, said second heater being an electrical heater 201 and a pump unit 110. The delivery module 100 is mounted in the bottom wall 510 of the tank 500. The second heater 201 which is a flexible electric heater 120 is arranged around the pump unit 110.

The using of a flexible electric heater 120 has the advantage that immediate heater power is available reducing the start-up time at cold temperatures. A supply rate of the electrical heater may be between 150 and 350 g/h. The first heater 200 which is a tubular heater may be an electric tubular heater or a fluid tubular heater. In the case of a fluid tubular heater, said heater 170 is used for circulating engine coolant. The heater power of the fluid tubular heater 170 will depend on engine heat up speed, and without the flexible electric heater 120 the start-up time will be much longer. By suitably combining an electrical heater with a tubular heater for engine coolant an optimal heating can be achieved fulfilling the start-up requirements whilst at the same time using heat from the engine coolant one the engine is heated up sufficiently. The flexible electric heater may be controlled by a controller in function of the engine temperature, in order to heat more when the engine temperature is too low and less when the engine temperature is increasing.

Figure 8 illustrates a vehicle system for injecting demineralized water. The system comprises a tank 500 for storing a liquid, e.g. demineralized water. The tank 500 comprises a first heater (not shown) and a delivery module (not shown) comprising a pump unit 110 and a second heater (not shown). The system comprises also an injector 310. A feed line 350 connects the pump unit 110 to an injector 310. The injector 310 is coupled to a combustion chamber 400, either directly or through an air intake 200 upstream of the combustion chamber 400. The function of the pump unit 110 is to pump mineralized water from the water tank 500 through the feed line 350 to the injector 310. The function of the injector 310 is to inject demineralized water in the combustion chamber 400. The demineralized water may be directly injected in the combustion chamber or anywhere as long as the air provided to the combustion chamber 400 is cooled by the injected water.