AN ADSORBED NATURAL GAS SYSTEM FOR VEHICLES

Field of the Invention

The present invention relates to an adsorbed natural gas system for vehicles which aims to store, fill and use natural gas for natural-gas-driven-systems in motor vehicles. Background of the Invention

In automotive sector, many studies have been conducted since recent past in order to utilize fuels alternative to petrol. Natural gas, which is one of these alternative fuels, is the cleanest fuel and comprises the least carbon and the most hydrogen among the fossil fuels. Moreover, upon discovery of new natural gas sites, development of the natural gas vehicles, which are environmentally friendly, economic and reliable, has increased incrementally in the recent years. As of year 2014, there are more than 18 million natural gas vehicles and more than 16.5 million of this figure is comprised of light commercial vehicles and automobiles.

Today, various methods are being used for storage and usage of natural gas in vehicles. There are as follows:

Compressed Natural Gas (CNG): CNG method comprises storing the natural gas upon pressurizing it up to approximately 200 bars in ambient temperature and feeding it into the vehicle.

Liquefied Natural Gas (LNG): LNG method includes liquefying the natural gas at a temperature of -163°C and storing it in cryogenic tanks and feeding it to the vehicle. Both storage methods have advantages and disadvantages over each other, and the storage method selected in the vehicle differ according to area of use.

There is one more different natural gas storage method which has not been industrialized yet, while development studies thereon continue increasingly. In the said method, natural gas molecules are compressed to approximately 35 bar pressure and impregnated at ambient temperature on porous structures of carbon derivative or metal organic hybrid materials. Since storage can be performed at a lower pressure with this method, which is called Adsorbed Natural Gas (ANG) technology, tank costs can be reduced and also it provides economic advantage in understructure costs of natural gas filling stations. Since storage at low pressure eliminates the requirement of producing the tanks in cylindrical form; producing the ANG tanks in different forms provides the advantage of flexibility in terms of storage location in the vehicle.

Upon integration of ANG system to the vehicle, additional modifications are needed on the vehicle in heating/cooling system, fuel system and control system.

United States patent document no. US20140026868, an application known in the state of the art, discloses a hybrid vehicle which stored natural gas in adsorbed form. The invention describes conversion of a compressed natural gas tank to an adsorbed natural gas tank.

United States Patent document no. US20150001101, another application known in the state of the art, discloses a natural gas tank storage system for vehicles. The invention includes a guard tank in addition to the storage tank. The invention comprises a filter containing a heating mechanism and a valve which controls the pressure within the guard tank and storage tank. Thus, storing, filling and discharging natural gas are improved. Chinese patent document no. CN103133864, another application known in the state of the art, discloses a fuel system which uses adsorbed natural gas and liquefied natural gas systems together. The invention includes an adsorbed natural gas tank and a liquefied natural gas tank. These systems are connected to each other in parallel and thus the whole system provides advantages of both of the systems. Hence, it enhances natural gas usage efficiency.

Summary of the Invention The objective of the present invention is to provide an adsorbed natural gas system which enables natural gas storage, filling and usage processes in motor vehicles running on natural gas.

Another objective of the present invention is to provide an adsorbed natural gas system which stores natural gas in the form of adsorbed natural gas.

A further objective of the present invention is to provide an adsorbed natural gas system which is an adsorbed natural gas system that works together with compressed natural gas system.

Detailed Description of the Invention

The accompanying figures regarding the adsorbed natural gas system, which enables the natural gas systems to work together with ANG (Adsorbed Natural Gas) storage, are as follows:

Figure 1 is a schematic view of the adsorbed natural gas system for natural gas vehicles.

Figure 2 is a schematic view of the natural gas vacuum cycle.

Figure 3 is a schematic view of the natural gas filling cycle.

Figure 4 is a schematic view of the natural gas usage cycle. Figure 5 is a schematic view of the water cycle.

The components shown in the figures are each given reference numbers as follows:

1. Adsorbed natural gas system

2. Adsorbed natural gas tank

3. Natural gas vacuum cycle

31. Vacuum line

32. Vacuum valve

33. Vacuum opening

4. Natural gas filling cycle

41. Filling line

42. Filling valve

43. Filling opening

44. Regulator

5. Natural gas usage cycle

51. ANG line

52. Usage valve

6. Water cycle

61. Water line

62. Radiator

63. Three-way valve

64. Air conditioning system

7. Control unit

8. Compressed natural gas tank

M. Engine

Adsorbed natural gas system for natural gas vehicles (1) of the present invention comprises

- at least one adsorbed natural gas storage (2) wherein the natural gas is stored, - at least one natural gas vacuum cycle (2) which enables to discharge the natural gas from the adsorbed natural gas storage (2),

- at least one natural gas filling cycle (2) which enables to fill natural gas into the adsorbed natural gas storage (2),

- at least one natural gas usage cycle (5) which enables the natural gas to be delivered from the adsorbed natural gas storage (2) to the engine in order to be used,

- at least one water cycle (6) which enables to control temperature of the adsorbed natural gas storage (2) during use,

- at least one control unit (7) which controls the operations of the system via the information received from the sensors and controls the concerned valves.

The adsorbed natural gas storage (2) is in the form of a tank which stores natural gas by means of the porous materials provided therein. Since the pressure of the natural gas stored therein is not as high as it is in the compressed natural gas technology, it is possible to produce and place the tank in the vehicle in more suitable forms.

In adsorbed natural gas storage systems, it is important to empty the adsorbed natural gas tank (2) by vacuum operation prior to natural gas filling operation at the natural gas stations. Thus, it is enabled to completely fill the adsorbed natural gas tank (2) with gas and to attain complete adsorption. The natural gas vacuum cycle (3) comprises

- at least one vacuum line (31) through which the natural gas is vacuumed from the adsorbed natural gas tank (2),

- a vacuum valve (32) which controls passage of the natural gas through the vacuum line (31),

- at least one vacuum opening (33) which enables connection of the vacuum line (31) to the vacuum pump. During the vacuum operation, the vacuum opening (33) is connected to the vacuum pump and the vacuum pump is operated. The pressure value of the vacuum produced by the vacuum pump is monitored by the sensors provided in the vacuum line (31). When the pressure value measured by the sensor reaches a predetermined value, the vacuum valve (32) is opened and vacuum operation is started. When vacuum operation is completed, in other words, when the pressure value measured by the sensor reaches a predetermined value, the vacuum valve (32) is closed and vacuum operation is terminated.

In adsorbed natural gas storage systems, natural gas filling operation at the natural gas stations is performed according to compressed natural gas storages. The natural gas filling cycle (4) comprises

- at least one filling line (41) through which the natural gas is delivered to the adsorbed natural gas tank (2),

- a filling valve (42) which controls passage of the natural gas through the filling line (41),

- at least one filling opening (43) which enables connection of the filling line (41) to the natural gas station,

- a regulator (44) which adjusts the pressure of the natural gas received from the natural gas station to a pressure suitable to the adsorbed natural gas tank (2).

During the filling operation, the filling opening (43) is connected to the natural gas station and the filling operation is started. The pressure of the natural gas coming from the natural gas station is monitored by the sensors provided in the filling line (41). When the pressure value measured by the sensor reaches a predetermined value, the filling valve (42) is opened and the passage of the gas is started. When filling operation is completed, in other words, when the pressure value measured by the sensor reaches a predetermined value, the filling valve (42) is closed and filling operation is terminated. Delivery of the stored natural gas to the engine in order to be used as fuel is performed by the natural gas usage cycle (5). The natural gas usage cycle (5) comprises

- at least one ANG line (51) through which the natural gas is delivered from the adsorbed natural gas tank (2) to the engine,

- a usage valve (52) which controls passage of the natural gas through the ANG line (51).

Temperature of the adsorbed natural gas tank (2) is required to be controlled during usage. This process is carried out by a water cycle (6) operating in integration with the engine cooling cycle of the vehicle. The water cycle (6) comprises

- at least one water line (61) through which the engine coolant travels,

- at least one radiator (62) through which the coolant heated by the engine's (M) temperature discharges the heat out of the vehicle,

- at least one three way valve (63) which, when the adsorbed natural gas tank (2) is activated, enables the coolant to be delivered to the adsorbed natural gas tank (2) in order to heat the adsorbed natural gas tank (2) with the temperature of the engine (M).

When the engine (M) is operated when the adsorbed natural gas tank (2) is not active, the coolant travels within the water line (61) and sends out the heat it receives from the engine (M) by means of the radiator (62). When the natural gas system is activated, the adsorbed natural gas tank (2) is required to be heated. The three-way valve (63) sends the coolant which leaves the engine (M) to the adsorbed natural gas tank (2) without sending it to the radiator (62) thereby enabling to heat the adsorbed natural gas tank (2) by means of a part of the heat of the engine (M). Temperatures of the adsorbed natural gas tank (2) and the water cycle (6) are controlled via the sensors. When the sensors detect that predetermined temperature values are reached, the control unit (7) adjusts temperature of the adsorbed natural gas tank (2) by controlling the three way valve (63). In a preferred embodiment of the invention, engine (M) heat and cabin temperature can be controlled by incorporating the vehicle air conditioning system (64) to the water cycle (6). In a preferred embodiment of the invention, the adsorbed natural gas tank (2) can be used together with the compressed natural gas tank (8). The compressed natural gas tank (8) works together with the adsorbed natural gas tank (2) in the natural gas filling cycle (4) and natural gas usage cycle (5).