Claims:We Claim:

1. A method of detecting a degree of clogging in a fuel filter of an internal combustion engine using an Electronic control Unit (ECU), said method comprising the following steps: measuring (101) the voltage difference across the terminals of the battery; receiving (102) an instant value of fuel temperature through a sensor; calculating (103) an instant value of fuel injection quantity based on the instant value of acceleration; characterized in said method

calculating (104) an instant time delay to reach a minimum rail pressure;

comparing (105) the measured value of battery voltage, received value of fuel temperature, calculated value of injection quantity and at least the calculated value of time delay required to reach a minimum rail pressure with pre-determined data points to arrive at a value of degree of clogging of fuel filter;

indicating (106) the value of degree of filter clogging to the vehicle user.

2. The method as claimed in 1, where the indication of the value of degree of filter clogging can be either an audio indication or a visual indication.
3. An Electronic Control Unit (ECU) adapted to detect a degree of clogging in a fuel filter of an internal combustion engine, where the said ECU is capable of :

measuring (101) an instant value of battery voltage across the terminals of the battery;

receiving (102) an instant value of fuel temperature through a sensor;

calculating (103) an instant value of injection quantity based on instant value of acceleration ;

calculating (104) an instant time delay to reach a minimum rail pressure;

comparing (105) the measured value of battery voltage, received value of fuel temperature, calculated value of injection quantity and at least the calculated value of time delay required to reach a minimum rail pressure with pre-determined data points to arrive at a value of degree of clogging of fuel filter;

indicating (106) the value of degree of filter clogging to the vehicle user.

4. The ECU as claimed in Claim 3, where the indication of the value of degree of filter clogging can be either an audio indication or a visual indication.
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed

Field of the invention
[0001] The present disclosure relates to a method of detecting a degree of filter clogging in an internal combustion engine.

Background of the invention
[0002] Filtered Fuel is a primary need for functionality & durability of fuel injection components. Imperfect Filtration leads to malfunction of components which further affects engine performance. The filter in due course of time becomes clogged due to the trapping of suspended particles as they pass through a porous medium. This trapping progressively impedes and eventually stops the flow of the fuel. There is a need for dynamic health check of filter in order to determine the changeover frequency and know the efficiency of filtration.

[0003] Patent Application US6672147B1, Method for detecting clogging in a fuel filter in an internal combustion engine supply circuit concerns a method for detecting clogging in a fuel filter, between a fuel pressure regulator imposing a pressure towards the internal combustion engine downstream of the filter and an electric motor pump compressing fuel coming from the tank towards the regulator through the filter which consists in: determining the fuel pressure at the pump output and by considering it as the fuel pressure at the filter intake; determining the fuel pressure at the filter outlet as being the pressure imposed by the regulator; determining the pressure drop of the filter from the difference between the filter input and output pressure levels, and by comparing at least a value based on the pressure drop with at least a reference value to deduce therefrom information concerning the clogging condition of the filter.

Brief description of the accompanying drawings
[0004] Fig. 1 is a flow-chart for a method of detecting a degree of filter clogging in an internal combustion engine.

Detailed description of the drawings
[0005] Figure 1 is a flow chart for a method of detecting a degree of filter clogging in an internal combustion engine using an Electronic control unit (ECU) adapted to detect a degree of clogging in a fuel filter of an internal combustion engine. In step (101), the ECU measures an instant value of battery voltage across the terminals of the battery. In step (102) the ECU receives an instant value of fuel temperature through a sensor. In step (103) the ECU calculates an instant value of fuel injection quantity based on instant value of acceleration. In step (104) the ECU calculates an instant time delay to reach a minimum rail pressure. In step (105) the ECU compares the received values of battery voltage and fuel temperature, calculated value of injection quantity and at least the calculated value of time delay required to reach a minimum rail pressure with pre-determined data points to arrive at a value of degree of clogging of fuel filter. In step (106) the ECU indicates the value of degree of filter clogging to the vehicle user.

[0006] In step (105), the ECU compares the measured value of battery voltage, received value of fuel temperature, calculated value of injection quantity and at least the calculated value of time delay required to reach a minimum rail pressure with pre-determined data points to arrive at a value of degree of clogging of fuel filter. The pre-determined data points as depicted in Table 1, comprise a matrix of a range of values for each of a battery voltage, a fuel temperature, an injection quantity and at least a value of time delay to achieve a minimum pressure corresponding to a degree of filter clogging.

Filter
clogged
condition Battery
voltage,
in Volts Fuel
Temp
in degree celsius Fuel Injection
Quantity
mm3/ stroke Time delay to
Achieve min Rail
Pressure in milliseconds.
0% V1 T1 A1 D1
1% V2 T2 A2 D2
2% V3 T3 A3 D3
N% Vn Tn An Dn

Table 1

[0007] The time delay to achieve a minimum rail pressure is indicative of degree of filter clogging. But, the value of time delay to achieve a minimum rail pressure is also dependent upon the values of parameters like battery voltage, fuel temperature, and fuel injection quantity. For example the time delay (D) is highly correlated and directly proportional to battery voltage. D is highly correlated and inversely proportional to fuel temperature measured. D is correlated and directly proportional to fuel injection quantity. The relation between a range of values these parameters is mapped with a corresponding value of a degree of filter clogging.

[0008] For example if the measured value of voltage is V1, measured fuel temperature is T1, the calculated value of fuel injection quantity is A1 and the ECU calculates the value of time delay to reach a minimum rail pressure as D1, then it will indicate that the filter is 0% clogged. Similarly for various values of instant battery voltage, fuel temperature, fuel injection quantity, the calculated value of the time delay required to achieve a minimum rail pressure will be compared with the values Table 1 to give a degree of filter clogging.

[0009] In an embodiment the ECU indicates the value of filter clogging by displaying the value on a display unit provided on the dashboard of the vehicle. In another embodiment the ECU indicates the value of filter clogging by an audio notification to the user of the vehicle.

[0010] This idea is to develop a method of detecting a degree of clogging in a fuel filter based on analysis & prognosis of various data parameters of a Common Rail system. The degree of filter clogging is indicative of health and efficiency of the filter. This is an accurate and more precise method of determining filter clogging as it takes into account various parameters indicative of dynamic health of filter. This method eliminates the need of special filter clogging sensors to be installed inside the internal combustion engine, hence offering a cost-effective solution for the problem of checking the degree of filter clogging.

[0011] It must be understood that the embodiments explained in the above detailed description are only illustrative and do not limit the scope of this invention. Any modification to the method of detecting a degree of filter clogging in an internal combustion engine are envisaged and form a part of this invention. The scope of this invention is limited only by the claims.