CA2232387A1

CA2232387A1 - Fuel system for gaseous fuel vehicles

Info

Publication number: CA2232387A1
Application number: CA 2232387
Authority: CA
Inventors: Victor Dubinsky; John Heenan; Stephen A. Carter
Original assignee: Sherex Industries Ltd Canada
Current assignee: Individual
Priority date: 1998-03-17
Filing date: 1998-03-17
Publication date: 1999-09-17

Description

Title: FUEL SYSTEM FOR GASEOUS FUEL VEHICLES
Inventor(s): Stephen A. Carter John S. Heenan Victor Dubinsky Assignee: Sherex Industries Ltd.
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a fuel system for vehicles powered by gaseous fuels, such as propane or natural gas. In particular, the invention relates to an improved vehicle refuelling system for filling the vehicle gas storage cylinder. The refuelling system optionally incorporates an in-cylinder mounted pressure regulator and cylinder valve combined in one common manifold.
Description of the Prior Art There are a number of refuelling systems known in the art. Most public refuelling stations use a dome-load temperature compensation method. The dome load regulator has many disadvantages, such as high maintenance and frequent re-calibration, a large dispenser flow restriction, extreme cylinder under-filling, and tampering vulnerability.
The new generation of NGV fuelling systems use electronic temperature compensation (ETC) systems to refuel vehicles. ETC has eliminated many of the disadvantages attributed to the older dome-load temperature compensation method. However, ETC still has a number of problems. The vehicle becomes the major flow restriction, leading to some vehicle overfilling. Most cylinders are still under-filled, although at a higher percentage of full than possible with the dome-load method. Also, these systems are not able to sense or receive actual cylinder temperature. Finally, ETC systems can only be used in private fleet applications where each vehicle has identical on-board storage and plumbing (i.e. it is not suitable for mass market applications).
Accordingly, there is a need for a refuelling system which overcomes these disadvantages.
Prior art on-board systems include a cylinder valve with two or more of the following functions:
~ a quarter turn valve is required by law in the United States for emergency fuel isolation in the cylinder;
~ an in-cylinder or external solenoid to enable NGV flow when energized;
~ a mount to secure a pressure relief device (PRD) which prevents cylinder over-pressurization in case of fire;
~ a bleed port for an in-cylinder solenoid valve to allow the cylinder to bleed down so that the solenoid may be inspected or repaired;
~ a fill port to permit the flow of NGV into the cylinder; and ~ a cylinder valve which mounts into the cylinder neck to control NGV flow into the cylinder and out of the cylinder during engine operation.
SUMMARY OF THE INVENTION
It is an object of the invention to provide real time communication between the NGV refuelling system and the vehicle storage cylinder(s). The invention also obviates the need to estimate actual in-cylinder pressure and temperature.
In the invention, the station fill nozzle is connected to a vehicle fill receptacle, permitting the vehicle antenna and station antenna to send and receive electronic information from the vehicle to the station and vice versa. The vehicle antenna communicates with a

2 conventional vehicle electronic control unit (ECU) and the station antenna communicates with the station ECU. The vehicle ECU communicates with optional on-board circuits, such as an ignition cut-off circuit or a fuel gage circuit. Optionally, communication between the vehicle and station can be accomplished with an antenna fitted to the on-board ECU and a ground loop installed at the station, beneath where the vehicle to be refuelled stands.
The optional in-cylinder mounted pressure regulator and cylinder valve are combined in one common manifold preferably mounted within the neck of the cylinder, and include in-cylinder pressure and temperature sensors which transmit the data to the fuel system.
Further features of the invention will be described or will become apparent in the course of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be more clearly understood, the preferred embodiment thereof will now be described in detail by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is a schematic diagram of the fuel system according to the invention;
and Fig. 1A is a plan view of the cylinder valve according to the present invention;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Fig. 1 shows a fuel system where a NGV vehicle fill receptacle couples with a station fill nozzle in any suitable fashion. A conventional electronic station sender/receiver fitted around the nozzle electronically connects with a corresponding conventional vehicle

3 sender/receiver fitted around the vehicle fill receptacle when the station fill nozzle couples with the vehicle fill receptacle.
The station sender/receiver is in electronic communication with a station fuel control transmitter (FCT) which in turn is in electronic communication with the NGV dispenser and storage system. The dispenser and storage system uses conventional technology to collect information and store data on a wide variety of parameters, such as fuel metering.
Similarly, the vehicle sender/receiver communicates with a conventional vehicle information transmitter (VIT) which communicates with the in-cylinder pressure regulator/cylinder valve assembly. The VIT is able to receive information from the fuel temperature and pressure sensors which are part of the regulator/cylinder valve assembly.
Preferably, the VIT is able to send information to a conventional fuel gage display and an ignition cut-off sensor.
The in-cylinder pressure regulator/cylinder valve installed in the cylinder neck is shown in Fig. 1A, and a schematic of a two stage pressure regulator is shown in Detail A of Figure 1. The structure of the first and second stages of the pressure regulator is described in the above applicant's published PCT application no. WO 96/07129. However, a downstream, low pressure, third stage of pressure regulation, or any suitable high pressure regulator can be used and such a variation is within the scope of this invention. Preferably, the pressure regulator and cylinder valve are constructed in one common manifold.
Referring to Detail A of Fig. 1, the gas from the storage cylinder preferably passes through a one way check valve to prevent the flow of gas out of the cylinder. During refuelling, the pressure of the refuelling station is higher than the cylinder pressure, thus gas flow will open the check valve to allow the refuelling to proceed. However, during vehicle

4 operation the gas pressure in the cylinder will maintain the valve in the closed position so that the only exit from the cylinder is along the outlet line to the engine (described in detail below).
The gas then passes through a filter to remove dirt, oil and water from the fuel.
An instant-on solenoid is provided to prevent the flow of gas to the engine until the driver turns on the ignition. The gas then preferably enters the first stage of the pressure regulator where the pressure is dropped from 2000-5000 psig cylinder pressure to approximately 100-250 psig.
A conventional approved pressure relief device is provided to avoid damage to the second stage of the regulator (described below) or other downstream components, in the event that the first stage fails to reduce the pressure to the appropriate amount. The pressure relief valve is in fluid communication with a bleed screw to permit the solenoid to bleed down in the event that it has to be inspected or repaired. The gas, after passing the first stage, then enters the second stage of the regulator where the pressure is reduced to approximately 100 psig before it enters the engine. If a third stage, or lower pressure regulator, is used than the fuel's pressure at the engine ingestion point matches that of air at that same point.
Preferably, a pressure sensor and a fuel temperature sensor are mounted on the in-cylinder pressure regulator/cylinder valve. The sensors electronically communicate with the VIT.
The combination of the cylinder valve, pressure regulator, and sensors in one common manifold permits the construction of a device which takes up less space than known devices and permits a 70% reduction in components. The invention can be provided in multi-functional packaging, avoiding costly packaging for separate components. The outside exposure area is minimised, as most of the device is embedded in the storage cylinder. The device can be manufactured as one modular unit which can be easily removed, saving

5 maintenance and installation cost, time, and labour.
The in-cylinder pressure regulator can be installed directly into the storage cylinder, eliminating all mounting brackets required to mount known pressure regulators.
Unlike prior art devices, the cylinder valve/pressure regulator according to the present invention requires no high pressure fittings downstream of the regulator which amounts to approximately a 64% reduction in high pressure connectors. Furthermore, because the gas exits the outlet of the regulator under controlled low pressure, high pressure tubing and fittings can be eliminated.
The fuel system according to the present invention is able to provide a complete cylinder fill without overfilling by using the in-cylinder pressure and temperature sensors to control the fill algorithm. The elimination of overfill prevents the over-stressing of cylinders.
If the fuel line of a NGV vehicle is ruptured during an accident, the in-cylinder solenoid will reduce the chances of the gas escaping from the storage cylinder. The wires of the solenoid are more delicate than the fuel line and will likely also tear during an accident. This will cut off power to the solenoid, causing it to close and cutting off the flow of gas out of the storage cylinder.
The FCT is able to store information relating to pre-authorized vehicle fleet accounts and will be able to record and transmit fuel purchase accounts electronically using known technology. In addition, the FCT is able to store data on the identity of vehicles permitted to use the station and is able to cross-reference this data with information from the VIT to permit only pre-authorized vehicles to fill. The FCT is able, using known technology, to prevent fuel from being dispensed unless all security checks are in place.
The in-cylinder mounted pressure regulator permits for installation of long-life

6 sensors which are permanently embedded in the operating milieu, and, accordingly, are not subject to atmospheric conditions and corrosion.
The VIT electronics and the sensors mounted on the in-cylinder pressure regulator allow for cylinder health and life expectancy data to be stored, calculated, and updated, allowing for an optimal but safe cylinder life. Furthermore, the life expectancy calculations are preferably able to take into account varying supply pressures and adjust the life expectancy of the storage tank accordingly.
The optional ignition lock out circuit is usually a separate circuit in electronic communication with the VIT, but may also be incorporated as part of the VIT.
The station FCT
is adapted to send a signal to the ignition lock out circuit in appropriate circumstances, such as in the event that an unauthorized vehicle attempts to refuel or if the vehicle is running while the driver attempts to refuel.
It will be appreciated that the above description relates to the preferred embodiment by way of example only. Many variations on the invention will be obvious to those knowledgeable in the field, and such obvious variations are within the scope of the invention as described and claimed, whether or not expressly described.

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