DESC:FIELD OF INVENTION

The present invention relates to a method for measuring the fuel-economy of automobiles. In particular, the present relates to a method for measuring the fuel-economy of automobiles which requires minimum modifications to the automobile. More particularly, the present invention relates to a method for measuring the fuel-economy of automobiles which uses an optimal placement of the auxiliary fuel tank for easy access during the measurements.

BACKGROUND OF THE INVENTION

With ever increasing prices of the fossil fuel such as petrol and diesel, there is always tremendous pressure on the automobile manufacturers to meet the customer expectations in terms of lower fuel consumption and thereby getting higher fuel efficiency. Moreover, due to global warming of the planet, there is additional pressure on the automobile manufacturers to be more committed to the environment protection and energy conservation to comply with more stringent emission norms. The feed pump is one of the major sub-assembly contributing to improve the fuel economy. It is usually unregulated and consumes 100% power at all the times irrespective of the engine being run in idle speed or in rated speed or even at full load. The fuel economy measurement is now one of the most important aspect for judging the performance of any new vehicle apart from emission control.

In diesel engines with Common Rail Injection, the fuel pump supplies fuel to the injector pump to feed it to the fuel injectors. This high-pressure fuel is injected depending on fuel demand from the automobile engine. The rate at which fuel is pressurized to fill the fuel rail is higher than the consumption of the engine at part load condition. Therefore, for protecting the rail and also to control the injection pressure as desired, additional fuel is leaked-off to the fuel tank. One of the applicant’s model MAXXIMO works on a similar fuel system, in which the fuel pump is continuously working at its fullest potential irrespective of the fuel demand from the engine.
Fuel is continuously fed from intake feed pump to high pressure pump in all operating conditions and the excess fuel is leaked-off from common rail to be returned to the fuel tank.

Typically, a fuel meter integrated with a pump is used for fuel economy measurement. This pump would provide the constant pressure required for functioning of the common rail system. This is almost same as the conventional fuel system.

However, in the new FPC (Feed Pump Control) technology, fuel feed pump is directly controlled by ECU (Engine Control Unit) and outlet pressure of the pump is regulated depending upon operating conditions. Hence, it has posed a lot of challenges for fuel consumption measurement during development thereof.

The fuel meter could not be incorporated into the circuit, because this would have led to additional pressure drop and increased power consumption by feed pump, which will significantly affect the fuel economy value under measurement.

Further, the fuel flow meter addition would increase the length of fuel line and thus result in an increased power consumption by fuel pump, which in turn would lead to a higher fuel consumption. Moreover, by using a fuel meter in the circuit, the measurement accuracy drops significantly for small vehicles having low fuel consumption of less than 0.1 lit/hr.

WORKING OF PCV SYSTEM: A Pressure Control Valve (PCV) circuit consists of an In-tank pump which is connected to the fuel injection pump through the fuel filter. High pressure fuel is stored in common rail, from where it is fed to the injector based on ECU control. Fuel returned from the high-pressure pump, common rail as well injectors are combined together and returned back to the tank. In such a PCV circuit, the injection pressure is controlled by regulating the pressure at the common rail by means of a Pressure Control Valve operated directly by ECU.
However, the energy spent on the fuel feed pump is quite high on this circuit, because the outlet pressure of fuel feed pump is always maintained constant. The fuel pressure on the low-pressure line is maintained constant because the fuel pump operates continuously and any excess fuel is leaked off to the fuel tank.

WORKING OF FPC SYSTEM

This FPC circuit is also similar to the PCV system, but here the in-tank pump is controlled by Engine Control Unit (ECU) and the fuel delivery pressure is accurately metered within the feed pump itself.

Therefore, the power consumption for operating the fuel pump is substantially reduced. Moreover, the excess fuel quantity sent to system is also less than the conventional pressure control valve-based system.

There are different methods for fuel consumption measurement, some are based on volumetric measurement of fuel flow or on gravimetric measurement or on weighing of fuel tank before and after test etc. However, the predominantly used method for on-road fuel consumption measurement is by top-up and fuel meter.

The conventional way of measuring fuel economy is TOP-UP method, in which the fuel is filled up to the fuel tank brim before starting the test. At the end of test, the fuel is refilled to the fuel tank brim, which equals the amount of fuel consumed during the test. Accordingly, the fuel economy is calculated as the total distance travelled by fuel consumed. However, this method involves higher human intervention, because the accuracy of the method depends on a proper venting of air present inside the fuel tank. The vehicle needs to be rocked several times to ensure the complete fuel refilling of the fuel tank. This is even more complex when the fuel tank shape is complex or when the split fuel tank is used as in Applicant’s model XUV. Another fuel flow meter-based measurement is more accurate and involves much less human intervention. Here, the fuel meter is fixed in between the fuel tank and engine and a constant pressure is maintained either by the fuel pump integrated with the fuel meter or by the in-tank pump. Moreover, fuel meters with chillers help in cooling down the fuel to maintain the fuel density. The fuel meters make the testing easier because the fuel consumption can be monitored at regular intervals. Most of the present-day cars are tested by this method.

Therefore, the only available option is to revert to the conventional “Top-Up” method for the fuel consumption measurement, in which the fuel tank is filled 100% before the start of the test and after running a predefined distance, the fuel tank is again refilled to 100% thereof. Finally, the fuel consumption is calculated based on the distance travelled and the topped-up fuel quantity.

However, this method includes a measurement error of up to 10% due to reasons such as air entrapment, complex shape of the need for multiple shake-up of the vehicle during fuel-tank top-up etc.

DISADVANTAGES WITH THE PRIOR ART

Current automotive vehicles comprise pressure control valve (PCV) with a constant pressure outlet from the in-tank pump unit. So, the fuel meter can be fitted on these vehicles without any modifications, but Feed pump control unit is controlled by ECU. The fuel meters work under a constant pressure, whereas the FPC system controls the fuel pump based on fuel demand from the engine management system.

Hence, it becomes impossible to use a fuel meter on an FPC system and the only available option is to use the conventional top-up methods.

The disadvantages of conventional top-up methods have already been discussed above.

To overcome these disadvantages, a new method is proposed in accordance with the present invention, which requires minimal modification of the vehicle.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide an improved method for measuring the fuel-economy of the automobiles, which requires minimal changes to the existing vehicle.

Another object of the present invention is to provide an improved method for measuring the fuel-economy of the automobiles, which can be cross-deployed on any other vehicle models equipped with FPC system.

Still another object of the present invention is to provide a improved method for measuring the fuel-economy of the automobiles, which substantially improves the measurement accuracy.

Yet another object of the present invention is to provide an improved method for measuring the fuel-economy of the automobiles, which can be cross-deployed in all FPC vehicles with minimal change and at least cost.

A further object of the present invention is to provide an improved method for measuring the fuel-economy of the automobiles, which requires no additional costs for making the required auxiliary fuel tank.

A further object of the present invention is to provide an improved method for measuring the fuel-economy of the automobiles, which substantially reduces the fuel topping up time during refilling.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a method for measuring the fuel-economy of vehicles using an optimally placed and accessible auxiliary fuel tank for easy lifting and tilting thereof for venting air trapped therein during fuel economy measurement.

Typically, the method comprises placing an auxiliary fuel tank on the cargo/cabin area of the vehicle by means of brackets introduced for holding said auxiliary fuel tank at an inclination, preferably at an inclination of 30 to 500 with a minimum head loss to the fuel pumping system and the fuel filling neck thereof facing upwards for proper air venting of the fuel tank.

Typically, the method comprises placing an auxiliary fuel tank substantially smaller than the existing fuel tank disconnected and replaced by said auxiliary fuel tank.

Typically, the method comprises replacing the existing fuel injection system with common rail and having pressure control valve by fuel distributor block.

Typically, the method comprises metering fuel quantity at feed pump itself.

Typically, the method comprises extending the fuel lines and the wiring harness of said disconnected existing fuel tank of the vehicle to said auxiliary tank.

Typically, the method comprises pumping the fuel from said auxiliary tank based on the fuel demand from the engine.

Typically, the method comprises a complete filling of said auxiliary fuel tank to the brim thereof, before and after the test and tilting a bit to remove any air bubbles trapped during fuel filling, preferably the capacity of said auxiliary tank is about 10 Liters without making any major change to the tank setup for the fuel economy measurements carried out thereby.

Typically, the method comprises accurately controlling the fuel quantity pumped by the fuel pump by means of the engine management system of the engine control unit (ECU).

Typically, the method comprises arranging the fuel tank with a minimal increase in the length of said fuel line, preferably an increase of about 20 to 25 cm length having no kink or curls in said fuel line; wherein routing of said wiring harness and fuel line does not protrude outside the vehicle.

DESCRIPTION OF THE INVENTION

To overcome the abovementioned problems, an enhanced top-up method is developed by the applicant, in which an auxiliary tank is fitted on the cargo area with electrical connections to ECU with minimal increase in the fuel line length. This auxiliary tank is connected such that the fuel tank can be easily tilted, and trapped air can be removed before and after filling the fuel.

The applicant has developed an improved method for measuring the fuel economy, in which the fuel required by the engine at feed pump is metered inside the fuel tank itself and only the fuel quantity demanded by ECU is pumped. This reduces electrical and pumping as well as hydraulic losses to save fuel for enhancing energy and/or fuel economy measurement efficiency by up to 5%.

This novel top-up method also improves the measurement accuracy by restricting the fuel measurement error to less than 2%. This method has been successfully developed for vehicles having FPC technology including applicant’s vehicle models Jeeto and Supro.
Accordingly, this specification discloses a detailed description of the difference between the existing method of fuel economy measurement and the new method based on a new fuel consumption measurement technique discussed above, which includes:

• Overcoming the difficulties faced while measuring fuel consumption by using novel feed pump control device reducing criticality of measurement.

• Employing the new fuel measurement method without much vehicle modification.

• Ensuring the reliability and consistency of new measurement methodology.

NEW FUEL ECONOMY MEASUREMENT METHOD

Accordingly, for measuring the fuel economy better and for gaining cost-advantages, the existing fuel injection system with common rail having a pressure control valve, e.g. in MAXXIMO model, is replaced by a fuel distributor block. Now, the fuel quantity is metered at the feed pump itself, instead of at the pressure control valve.

The existing fuel tank is disconnected and replaced in the cargo / cabin area of the vehicle by a smaller auxiliary tank of the same configuration. The fuel lines and the wiring harness of the vehicle are extended to this auxiliary tank. As a result, fuel from this tank is pumped depending on the fuel demand from the engine.

An accurate fuel pump control is carried out by the engine management system of ECU. Since a smaller tank is placed in an area where it can be accessed easily, it is easy to lift and tilt the tank for air venting. This ensures complete fuel tank filling to the brim thereof and thus enables an accurate calculation of the fuel consumption.
The fuel is filled before and after the test up to the brim of the fuel tank and the tank is tilted a bit, if there are bubbles existing inside the fuel tank fixed on the cargo, such that air bubbles trapped during fuel filling are removed.

In the new method for fuel economy measurement, the fuel quantity required for measurement is approximately 10 to 15 Liters. Here, instead of using a smaller auxiliary tank of same configuration, a vehicle tank with a capacity of about 10 Liters is used without making any major change to the tank setup for fuel economy measurements.

Since the fuel tank is normally required to be placed in an area easily accessible, the existing fuel tank is disconnected and instead placed in the cargo / cabin area of the vehicle. For matching the length of the existing fuel line, this fuel tank is arranged such that only a minimal increase of 20 to 25 cm length is required without any kink or curls in the fuel line, so as not to affect the fuel flow.

Therefore, fuel from this rearranged fuel tank is pumped depending on the requirement from the vehicle engine. The fuel pump is accurately controlled by the engine management system of ECU. Further, the wiring harness length is modified to connect the In-tank pump.

The routing of wiring harness and fuel line is done such that it does not protrude outside the vehicle. For safety reasons, the wiring is also kept insulated. New brackets are introduced to hold the fuel tank at an inclination of 30 to 500 with a minimum head loss to the system and the fuel filling neck faces upwards for proper air venting of the fuel tank.

This ensures filling of the fuel tank till its brim and thus ensures an accurate calculation of the fuel consumption. The fuel is filled till brim before and after the test and the tank is tilted. The tank is fixed on the cargo in such a way that the air bubbles trapped inside the tank during fuel filling process, can be easily removed.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1 shows a schematic arrangement of the conventional Pressure Control Valve (PCV) Circuit.

Figure 2 shows a schematic arrangement of the Fuel-distributor Pressure Control (FPC) Circuit configured in accordance with the present invention.

Figure 3 shows a schematic arrangement of a conventional PCV to FPC Circuit equipped in an automotive vehicle.

Figure 4 shows an FPC Circuit of an automotive vehicle equipped in accordance with the present invention.

Figure 5 shows an actual vehicle set-up of the FPC Circuit equipped in accordance with the present invention on the in an automotive vehicle.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a schematic arrangement of the conventional Pressure Control Valve (PCV) Circuit, which comprises a fuel tank 10 with electric fuel pump 20, a fuel filter 30 without overflow valve, a high-pressure pump 40, a pressure control valve 100 with a common rail 50 and RPS4-18, an electronic injector 60 with two injectors Inj1 and Inj2 respectively, a check valve 62 connected downstream the electronic injector 60, other actuators 64 connected between the electronic injector unit 60 and PCV 100, an accelerator pedal input 70 and other sensors 66 connected between the accelerator pedal 70 and PCV 100, an engine cam and crank RPM input sensor 80 and electronic control module 90. High-pressure and low-pressure lines as well as sensor/actuator signal paths are also indicated.

Figure 2 shows a schematic arrangement of the Fuel-distributor Pressure Control (FPC) Circuit 200 configured in accordance with the present invention, which comprises a fuel tank 110 with electric fuel pump 120, a fuel filter (without overflow valve) 130, a high-pressure pump 140, a fuel distributor block 150, an electronic fuel injector 160 with two injectors Inj1 and Inj2, other actuators 162 connected between the electronic injector unit 160 and electric fuel pump 120 in the fuel tank 110, an accelerator pedal input 170 and other sensors 166 connected between the electronic injector unit 160 and the accelerator pedal 170 as well as the engine RPM sensor inputs 180, an engine RPM sensor input 180 and an electronic control module 190.

Figure 3 shows a schematic arrangement of the conventional PCV to FPC Circuit equipped in an automotive vehicle 400.

Figure 4 shows an actual vehicle set-up of the FPC Circuit configured in accordance with the present invention arranged in automotive vehicle 400.

Figure 5 shows an actual vehicle set-up configured in accordance with the present invention in an automotive vehicle by using a vehicle fuel tank with a capacity of about 10 Liters. Here, the existing fuel tank 10 is disconnected and replaced in the cargo / cabin area 300 of the vehicle 400 by a smaller auxiliary tank 110 of the same configuration. The fuel lines and the wiring harness of the vehicle are extended to this auxiliary tank 110. As a result, fuel from this tank 110 can be accurately pumped depending on the fuel demand from the engine by means of an engine management system (ECU). Due to use of a smaller tank 110 placed on the cargo/cabin, which is easily accessible and easy to lift and tilt for air venting purpose to ensure the fuel tank to be filled to the brim to enable an accurate calculation of the fuel consumption and thereby vehicle fuel economy.
CROSS DEPLOYMENT: VEHICLE FPC CIRCUIT ON JEETO

The same procedure which is developed for Supro pickup has been implemented on Jeeto and Supro minivan.

RESULTS:

ROUTE INCA TOP-UP DELTA
ON ROAD 26.5 kmpl 26.0 kmpl 1.9%
23.5 kmpl 23.7 kmpl 1.09%

Accordingly, the present invention is distinguished from the conventional top-up method of measuring fuel economy by a substantial improvement in the measurement accuracy.

The fuel economy measurement method devised in accordance with the present invention is implemented in the applicant’s vehicles with minimal non-destructive changes in fuel line and wiring harness.

Extensive fuel economy trials were conducted, and the results correlate within 2%. The results are as given below:

INCA (kmpl) Top-Up (kmpl) % Correlation
Vehicle A with FPC System 29.8 30 0.67
28.6 28.7 0.35

The new method was implemented and verified on the vehicles such as Supro truck, minivan and Jeeto, which are equipped with a FPC System.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The feed control device configured in accordance with the present invention has the following advantages:

• Requires minimal changes to the vehicle, which can be restored without any major changes.
• Cross-deployable on other vehicle models with FPC system vehicles.

• Improves the measurement accuracy as compared to the regular top-up measurement.

• Cross-deployable in all FPC Vehicles with minimal changes at least cost.

• Zero cost for making the auxiliary tank, because the same vehicle tank is used as auxiliary tank without any modification.

• Reduces the topping up time, i.e. just 10 to 15 minutes in comparison to 25 to 30 minutes required for the regular top-up measurement.

In the previously detailed description, different features have been summarized for improving the conclusiveness of the representation in one or more examples. However, the above description is merely illustrative, but not limiting under any circumstances. It helps in covering all alternatives, modifications and equivalents of the different features and exemplary embodiments.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept. Many other examples are directly and immediately clear to the skilled person because of his/her professional knowledge in view of the above description.

These innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships.

Therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description provided herein is purely by way of example and illustration.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure to achieve one or more of the intended objects or results of the present invention. Furthermore, the use of the term “one” shall not exclude the plurality of such features and components described.

Also, any reference herein to the terms ‘left’ or ‘right, ‘up’ or ‘down, or ‘top’ or ‘bottom’ are used as a matter of mere convenience and are determined by standing at the rear of the machine facing in its normal direction of travel.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

The various features and advantageous details are explained with reference to the non-limiting embodiment/s in the above description in accordance with the present invention.

The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

Furthermore, the various components shown or described herein for any specific application of this invention can be widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. When referring to the figures, like parts are numbered the same in all the figures. ,CLAIMS:We claim:

1. A method for measuring the fuel-economy of vehicles using an optimally placed and accessible auxiliary fuel tank for easy lifting and tilting thereof for venting air trapped therein during fuel economy measurement.

2. Method as claimed in claim 1, wherein said method comprises placing an auxiliary fuel tank on the cargo/cabin area of the vehicle by means of brackets introduced for holding said auxiliary fuel tank at an inclination, preferably at an inclination of 30 to 500 with a minimum head loss to the fuel pumping system and the fuel filling neck thereof facing upwards for proper air venting of the fuel tank.

3. Method as claimed in claim 2, wherein said method comprises placing an auxiliary fuel tank substantially smaller than the existing fuel tank disconnected and replaced by said auxiliary fuel tank.

4. Method as claimed in claim 1, wherein said method comprises replacing the existing fuel injection system with common rail and having a pressure control valve by a fuel distributor block.

5. Method as claimed in claim 4, wherein said method comprises metering the fuel quantity at the feed pump itself.

6. Method as claimed in claim 3, wherein said method comprises extending the fuel lines and the wiring harness of said disconnected existing fuel tank of the vehicle to said auxiliary tank.

7. Method as claimed in claim 6, wherein said method comprises pumping the fuel from said auxiliary tank based on the fuel demand from the engine.

8. Method as claimed in claim 7, wherein said method comprises a complete filling of said auxiliary fuel tank to the brim thereof, before and after the test and tilting a bit to remove any air bubbles trapped during fuel filling, preferably the capacity of said auxiliary tank is about 10 Liters without making any major change to the tank setup for the fuel economy measurements carried out thereby.

9. Method as claimed in claim 8, wherein said method comprises accurately controlling the fuel quantity pumped by the fuel pump by means of the engine management system of the engine control unit (ECU).

10. Method as claimed in claim 6, wherein said method comprises arranging the fuel tank with a minimal increase in the length of said fuel line with no kink or curls; wherein routing of said wiring harness and fuel line does not protrude outside the vehicle.

Dated: this 24th day of February 2017. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT