Claims:We Claim:
1. A gaseous fuel injection system layout for a multi-wheeled vehicle (100), the multi-wheeled vehicle (100) comprising:
a low pass filter (405);
a fuel injector (412);
a rail sensor (404);
an engine (201) supported on a chassis of the multi-wheeled vehicle (100), the engine comprising a cylinder head (203) and a crankcase (415);
a second stage reducer (401) which reduces pressure of the gaseous fuel, received through a high-pressure hose (403) at a high pressure, to a predetermined pressure level and provides the output to the low pass filter (405) through an input hose (402); and
a rail sensor (404) providing signal to electronic control unit based on temperature and pressure of the gaseous fuel, the rail sensor (404) integrally formed with the low pass filter (405).
2. The gaseous fuel injection system layout for a multi-wheeled vehicle (100)as claimed in claim 1 wherein the integrally formed low pass filter (405) and the rail sensor (404) are mounted to the crankcase (415) using a first mounting bracket (407).
3. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 1 wherein the gaseous fuel is transferred from the low pass filter (405) to a fuel injector (412) through a second path (408).
4. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 1 or claim 3 wherein an axis X-X’ of the fuel injector (412) along the second path (408) is obliquely inclined to a cylinder head axis Y-Y’.
5. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 4 wherein the injector hose along the second path (408) is curved outwardly away from the cylinder head axis Y-Y’.
6. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 3 wherein the fuel injector (412) is mounted on an intake pipe (414).
7. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 4 wherein an electrical coupler (413) of the fuel injector (412) and the injector hose axis X-X’ along the second path (408) are placed at an angle substantially equal to 180 degrees.
8. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 4 wherein a first cable guide (409) and a second cable guide (411), to guide the injector hose, are attached to the crankcase (415) and the cylinder head (203) respectively to support the injector hose along the second path 408.
9. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 4 wherein an imaginary plane passing through the cylinder head axis Y-Y’ forms a region A and a region B.
10. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 9 wherein region A includes the injector hose along the second path (408).
11. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 9 wherein region B includes the low pass filter (405) and the rail sensor (404).
12. The gaseous fuel injection system layout for a multi-wheeled vehicle (100) as claimed in claim 1 wherein the engine (201) is housed in an engine cabin (104) in rear of the multi-wheeled vehicle (100).
, Description:TECHNICAL FIELD
[0001] The present subject matter relates a multi-wheeled vehicle working on gaseous fuel and more particularly to an improved layout for fuel injection for multi-wheeled vehicle wherein an engine is disposed in rear portion of the vehicle.

BACKGROUND
[0002] Conventionally, a vehicle running on gas-based fuel includes a gas fuel storing container such as a cylinder wherein pressurized gas fuel is stored. The gas fuel from such a container undergoes various pressure reduction stages and ultimately gets fed to the engine at atmospheric / sub-atmospheric pressures to the engine. Prevalent fueling system is a vacuum-based system wherein the fuel is supplied at atmospheric / sub-atmospheric pressures to the engine. Combustion of gaseous fuel inside the engine leads to emission of exhaust gases comprising of hydrocarbons and other pollutants which leads to air pollution. It has always been an objective to minimize such emissions to reduce air pollution. Many a times when supply of fuel inside the engine is more than the demand, the unburnt fuel is emitted from the engine as emissions. One way to achieve this objective is to supply exactly required quantity of fuel inside the engine as per the demand of the engine. Recently, this requirement has been achieved by using processor controlled electronic fuel injections. These electronic fuel injectors supply metered quantity of fuel inside the engine thereby reducing the quantity of emissions per cycle of the combustion process. Furthermore, to reduce the emissions, it is required to migrate to fuel injection system with elevated pressures. Once the pressure is elevated, it leads to impurities entering the fuel injector nozzle. Hence, to avoid clogging of injectors (nozzles), it is preferred to filter the gaseous fuel prior to entry inside the fuel injector. A low-pressure filter (downstream of a second stage pressure reduction or third stage pressure reduction through appropriate reducer) is typically added for this purpose. Summarily, there exists a contradictory engineering requirement of designing a compact and efficient layout of a gaseous based fuel injection system in a vehicle while overcoming the thermal hurdles. Therefore, there is a need for an improved layout of a fuel injector system for a vehicle working on gaseous fuel which overcomes all of the above problems and other problems of known art.

BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The detailed description is described with reference to an embodiment of a three wheeled vehicle along with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0004] Fig. 1 illustrates a left side view of an exemplary vehicle, as per the present invention.
[0005] Fig. 2 illustrates a rear view of engine compartment of the three-wheeled vehicle.
[0006] Fig. 3 illustrates a perspective view of the engine compartment of the three- wheeled vehicle as per the present invention.
[0007] Fig. 4 illustrates a top view of the engine compartment as per an embodiment of the present invention.
[0008] Fig. 5 illustrates the mounting of the fuel injector on the intake pipe as per the present invention
[0009] Fig. 6 and Fig. 7 illustrate a perspective view of mounting of the low pass filter on the crankcase of the vehicle as per an embodiment of the present invention.
[00010] Fig. 8 illustrates a perspective view illustrating the injector hose routing in the engine cabin as per an embodiment of the present invention.
DETAILED DESCRIPTION
[00011] The fuel injectors open a nozzle for a predetermined duration thereby metering the quantity of fuel being supplied. This works fine with the fuel injectors as far as the density of the fuel remains constant. Also, for gaseous fuel-based engines, the density of the gaseous fuel is also dependent on the temperature of the gas. Hence, it becomes a challenge to meter an exact quantity of fuel to be supplied to the gaseous fuel-based engines. The problem of variation in density of gaseous fuel is minimized using a rail sensor which measures the temperature and pressure of the gaseous fuel prior and communicates the same to an electronic control unit which sends an appropriate signal to fuel injector for metering the gaseous fuel to be fed inside the engine. But, a temperature variation between the rail sensor and a fuel injector may also lead to inaccurate data for the electronic control unit. Hence, the injector hose between the rail sensor and the fuel injector cannot be too long. Further, if the rail sensor is placed near the fuel injector, the heat generated from the engine may further lead to inaccurate signal from the rail sensor to the electronic control unit.
[00012] The description below now explains various features of the present invention. According to an embodiment, of the present invention and to obviate the problem of inaccurate signal from the rail sensor due to varying density of gaseous fuel, an improved fuel injection system layout is designed such that the inaccuracy of signal is resolved by configuring the location of the rail sensor away from the cylinder head. Further, since a longer distance between the rail sensor and the fuel injector is not desirable, according to an embodiment of the present invention, the rail sensor is mounted on the low pass filter and the low pass filter itself is mounted on crankcase of the engine using a first mounting bracket. The layout as per the present invention achieves an optimal distance between the rail sensor and the fuel injector and thereby enables achieving the contradictory requirements simultaneously. Further, since various elements of the present invention such as the fuel injector, the injector hose routing, low pass filter, rail sensor, the inlet hose and the high pass filter are configured in lateral direction of the vehicle, the vehicle width increases. Hence, to reduce the width of the vehicle and to contain all the above elements within the restricted vehicle width, the fuel hose routing becomes challenging. If the above elements are placed too closely, the injector hose and the input hose tend to have sharp bends resulting in breakage of either the injector pip or the injector hose and the input hose at the location of the bend. This reduces the life of the fuel injector, injector hose and the input hose. The damage results in frequent servicing, adding extra cost of maintenance to the customer, which is undesirable. Hence, it is desired to provide an injector hose and the input hose routing without sharp bends to increase life of the fuel injector, injector hose and the input hose.
[00013] Hence, to achieve the above objectives and to obviate the above problems, the present invention describes an improved layout wherein the low pass filter and a rail sensor are optimally disposed. Also, the present invention, in yet another embodiment, describes an injector hose and the input hose routing without sharp bends to increase life of the fuel injector. It is contemplated that the concepts of the present invention may be applied to any type of vehicle employing the similar configuration within the spirit and scope of this invention. Further "front" and "rear", and "left" and "right" referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen siting on the driver seat in the driver cabin of the three wheeled vehicle. Furthermore, a longitudinal axis unless otherwise mentioned, refers to a front to rear axis relative to the load deck, while a lateral axis unless otherwise mentioned, refers generally to a side to side, or left to right axis relative to the load deck. The detailed explanation of the constitution of parts other than the present subject matter which constitutes an essential part has been omitted at suitable places. The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00014] Fig. 1 illustrates a left side view of an exemplary three wheeled vehicle, as per the present invention. A three wheeled vehicle is shown for brevity and the present invention is applicable to a vehicle with more than three wheels also until the engine of the vehicle is located in rear portion of the vehicle behind a passenger cabin. Fig. 1 shows a three wheeled vehicle 100, driver cabin 101, driver seat 102, passenger cabin 103, engine cabin 104, front wheel 105, rear wheel 106, a partition wall 107. The present invention is also applicable to vehicles wherein the engine is located in front of the vehicle. For brevity, the presently illustrated three wheeled vehicle has the engine located on rear portion of the vehicle behind the passenger cabin 103. In the vehicle illustrated in the present invention, the driver cabin 101 is separated from the passenger cabin 102 using the partition wall 107. For a vehicle using gaseous fuel, it is desirable to keep the engine in the rear portion of the vehicle to safeguard the vehicle, engine and the combustible gaseous fuel during accidents or collisions from the front. In such a vehicle, the engine is placed along the longitudinal direction of the vehicle for ease of serviceability.
[00015] Fig. 2 illustrates a rear view of engine compartment of such a three-wheeled vehicle. Fig. 2 shows an engine 201 placed within the engine cabin 104. In this rear view of the vehicle, front wheel 105, rear wheel 106 and rear wheel 106' are also shown. For vehicle’s balancing purposes and equal transmission to the wheels, the engine is placed closer to the central longitudinal axis of the vehicle. This axis passes through the center of the vehicle from front to rear. With such configuration of the engine, the disposition of the gaseous fuel container, various reducers for different stages of pressure reduction, air filter, fuel hoses and the fuel injector become challenging. Further, in such a vehicle providing routing of the gaseous fuel hose from the gaseous fuel container to the engine without any sharp bends becomes more difficult. All the packaging of the vehicle as to be achieved within the restricted space of the vehicle to avoid increase in width of the vehicle.
[00016] To achieve the above objective, Fig. 3 illustrates a perspective view of the engine compartment of the three- wheeled vehicle as per the present invention. Fig. 3 shows the engine 201 positioned vertically inclined to the longitudinal axis of the vehicle below a horizontal frame member 301 and above an exhaust muffler 303. A gaseous fuel hose 302 is also shown above the cylinder head 203. The gaseous fuel hose consists of two parts: a first part 402between a high pass filter (also called as second stage reducer, the names have been used interchangeably and mean the same) and the low pass filter and a second part 408 between the low pass filter and the fuel injector. One of the challenge is to minimize and optimize this gaseous fuel hose length.
[00017] In order to minimize the hose length as discussed above and to optimize the hose length so that the variation in rail sensor’s signal between what is measured at the low pass filter and what is fed to the fuel injector is minimum, an improved layout is configured. Fig. 4 illustrates a top view of the engine compartment as per an embodiment of the present invention. Fig. 4 shows a second stage reducer 401 which reduces pressure of the gaseous fuel, received through a high-pressure hose 403 supplied at a high pressure from a fuel pump (not shown), to a pressure closer to atmospheric pressure level or a predetermined level and provides the output to a low pass filter 405 through an input hose 402. This low pass filter 405 further reduces the pressure of the gaseous fuel to an atmospheric or sub atmospheric level. A rail sensor 404 is either integrally formed or attached to the low pass filter 405 and the low pass filter 405 is mounted to the crankcase 415 of the engine 201 using a first mounting bracket 407 so as to provide a rigid support to both the low pass filter 405 and the rail sensor 404. The low pass filter 405 filters any dust or impurities inside the gaseous fuel so as to avoid blockage/clogging of nozzle of a fuel injector 412. Generally, the region in vicinity of the cylinder head 203 is hotter compared to the region in the vicinity of the crankcase 415. Hence, the rail sensor and the low pass filter 405 are configured adjacent to the crankcase 415 to avoid any excess heat to the rail sensor and the low pass filter.
[00018] Fig. 4 further illustrates a shorter first path 406 according to a known art wherein the shorter first path 406 connects the gaseous fuel from the low pass filter 405 to the fuel injector 412 with the axis of the shorter first path 406 lying substantially along a cylinder head axis Y-Y’. An imaginary plane passing through the cylinder head axis Y-Y’ partitions the engine into two regions, namely a region A and a region B. When the axis of the shorter first path 406 lies along the cylinder head axis Y-Y’, there is a sharp bend formed on the injector hose along the shorter first path 406 which leads to frequent cracks and damage of the injector hose along the shorter first path 406. To resolve this problem, according to an additional embodiment of the present invention, an axis X-X’ of the fuel injector is oriented at an angle away from the axis Y-Y’ and the injector hose is configured along a second path 408 which is obliquely inclined to the cylinder head axis Y-Y’ and the second path 408 is curved around outwardly away from the cylinder head axis Y-Y’. In this configuration, sharp bend of the injector hose along the second path 408 is avoided. In the above configuration, the region A accommodates the injector hose along the second path 408 and the region B accommodates the low pass filter 405 and the rail sensor 404. This configuration helps in eliminating the kink & sharp bend formation of the injector hose along the second path 408 as well as avoid thermal issues for the functioning of the rail sensor cum hose while additionally achieving shortest hose length.
[00019] Figure 4 also shows a first cable guide 409, and a second cable guide 411 attached to the crankcase 415 and the cylinder head 203 respectively to support the injector hose along the second path 408. An electrical coupler 413 is used to connect the fuel injector 412 to a power supply and for obtaining signal from the electronic control unit. The first cable guide 409 and the second cable guide 411 provide support to the injector hose and thereby avoid the vibration and noise produced due to shaking of the fuel hose. It also avoids contact of the injector hose 408 with the hot surfaces such as cylinder head 203.
[00020] Fig. 5 illustrates the mounting of the fuel injector on the intake pipe 414 as per one embodiment of the present invention. Fig. 5 shows the fuel injector 412 mounted on the intake pipe 414. The coupler 413 and intake pipe 414 are placed substantially orthogonal to each other and the injector hose axis X-X’ along the second path 408 is placed 180 degrees to the coupler 413 while being substantially orthogonal to the intake pipe 414. This configuration enables ease of maintenance and serviceability of the fuel injector and the injector hoses. Since the rail sensors are heavily sensitive to temperature and pressure variations, frequent calibration is required for the rail sensors. Further, this present layout configuration also enables ease of calibration of rail sensor.
[00021] Fig. 6 illustrate a perspective view of mounting of the low pass filter 405 on the crankcase of the vehicle as per an embodiment of the present invention. Fig. 7 shows injector hose 408, cylinder head 203, rail sensor 404 attached to low pass filter 405 and the first mounting bracket 407 mounted to the crankcase 415. The first mounting bracket 407 is provided with sufficient stiffening to withstand the engine vibrations according to the resonating frequency of vibration of the engine.
[00022] Fig. 8 illustrates a perspective view of the low pass filter 405 mounting and injector hose 408 routing and illustrating the injector hose routing in the engine cabin as per an embodiment of the present invention. Fig. 8 shows engine cabin 104, coupler 413, horizontal frame member 301, injector hose 302, input hose 402, high pressure hose 403, low pass filter 405, a first path 406 and a first mounting bracket 407 on crankcase 415. The low pass filter 405 present in the engine cabin 104 according to present invention enables ease of access to filter element in vehicle condition without removal of fuel filter from vehicle. Further since low pass filter 405 is located in the region B away from hot surfaces of cylinder head and cylinder block, it can be accessed without endangering technician’s hands thus improves serviceability of the low pass filter.

List of references
100 - three wheeled vehicle
101 - driver cabin
102 - driver seat
103 - passenger cabin
104 - engine cabin
105 - front wheel
106 - rear wheel
107 - partition wall
201 - engine
203 - cylinder head
301 - horizontal frame member
408 - injector hose
303 - exhaust muffler
401 - second stage reducer
402 - input hose
403 - high pressure hose
404 - rail sensor
405 - low pass filter
406 - injector hose along a shorter first path
407 - a first mounting bracket
408 - injector hose along a second path
409 - a first cable guide
410 - cylinder axis
411 - a second cable guide
412 - fuel injector
413 - coupler
414 - intake pipe
415 - crankcase
106' - rear wheel
Y-Y' - cylinder axis