Field of the invention
[0001]This invention relates to the field of oil dilution detection in engine.
Background of the invention
[0002] Lube oil is used for lubricating components of engine. The engine receives high pressure fuel from fuel injection pump via an injector. In case of fuel lubricated fuel injection pump, there are chances of fuel that that is used to lubricate the parts of the pump to mix with the lube oil. Dilution of oil results in decrease in lubrication capacity of oil and reduces the efficiency of engine leading to wear and tear of components/ parts of the engine.
[0003] Prior art patent application JP2004340090A discloses an engine oil viscosity control system for controlling viscosity of engine oil of the internal combustion engine is provided with a fuel injection valve directly injecting fuel into a cylinder of the internal combustion engine, an engine oil viscosity determination means determining whether viscosity of engine oil of the internal combustion engine is higher than a predetermined viscosity, and an engine oil dilution means injecting fuel from the fuel injection valve during a non-combustion period of each cylinder to adhere the fuel on an inner wall surface of the cylinder when the engine oil viscosity determination means determines that viscosity of engine oil of the internal combustion engine is higher than the predetermined viscosity.
Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description
and illustrated in the accompanying drawing:

[0005] FIG. 1 illustrates a method of detecting oil dilution in an engine.
Detailed description of the embodiments
[0006] FIG. 1 illustrates a method of detecting oil dilution in an engine. The engine comprises at least a flow path for flow of oil, the flow path comprises at least one pressure switch, the method comprises, receiving 100 by a control unit, a coolant temperature of an engine as an input. The control unit checks 102 if the coolant temperature corresponds to engine operating temperature. A feedback value from at least one pressure switch is received 104 by the control unit. The received feedback value of pressure is compared 106 by the control unit with a corresponding value of viscosity stored in a data map. The control unit verifies 108 if the value of viscosity corresponds to oil dilution. In case of oil dilution the value of dilution is indicated on a display device.
[0007]The working of the above mentioned method will be explained in further detail. The proposed method is used to detect oil dilution in engine and also to alert a user and or owner of the vehicle in case the oil dilution exceeds safety limit as prescribed during engine calibration. Oil is used in the engine to lubricate components of engine and also to prevent wear and tear of the components of engine. During working of the engine, the chemical property of the oil is such that due to change in temperature or due to dilution of oil with fuel, the pressure at which the oil lubricates the components of engine changes. For the purpose of better understanding, consider that for a flow rate of oil at 0.5 L/min, the viscosity of un-diluted oil is 91cP and at the said viscosity the oil operates at a pressure of 91 bar. Now, as the dilution of oil with fuel increases, the pressure at which oil lubricates the components of the engine changes. Consider for an oil dilution level of 20 percent, the viscosity with which the oil lubricates the components of the engine is 80 bar. As the dilution

of fuel with oil increases, the ability of oil to lubricate parts/components of the engine decreases. This leads to wear and tear of the components of engine. In order to avoid dilution of oil, the method proposes the following steps.
[0008] In order to detect oil dilution in the engine, the control unit receives the coolant temperature as an input. Coolant temperature is used as a parameter to ensure that engine is operating at a temperature (engine operating temperature) that is required for generating the rated power and torque. The control unit then checks if the coolant temperature corresponds to engine operating temperature, in other words, the temperature of coolant must be sufficient enough to maintain the operating temperature of the engine for maintaining rated power and torque. A feedback value is received 104 by the control unit from at least one pressure switch. The feedback value may be the pressure of oil. The pressure switch senses the pressure of oil and this is communicated to the control unit. The pressure switch is designed to sense the pressure of oil at different magnitude of pressures. The pressure switch is calibrated in a manner such that for different levels of dilution, the signal that is sent by the pressure switch is different. This difference in signal based upon the level of dilution gives an indication of the extent of dilution that has happened with respect to oil. The magnitude of pressure that is received by the control unit is compared with the value of viscosity stored in data map. Since viscosity of oil is a function of pressure this information of viscosity obtained from the data map is used as a reference for arriving at the level of dilution in oil.
[0009]The indication of level of dilution in oil may be based upon the extent to which fuel has mixed with oil. The indication may be in the form of no dilution, normal or acceptable level of dilution in case the extent of oil dilution does not

affect the capacity of oil to lubricate parts of the engine, and in case the viscosity exceeds the limit as defined for oil, an indication signifying the same may be provided. Consider the case where the engine oil is used for lubricating components of engine. Initially it is assumed that the oil is in undiluted state. As the oil lubricates parts of the engine, the pressure of oil during undiluted state is received by the control as an input from the pressure switch. At this pressure the viscosity of oil is compared from a data map, since for a particular oil viscosity during undiluted state is defined it is understood that there is no dilution of oil and the indication is given that there is no dilution. Moving further as the fuel mixes with oil there is a change in the pressure at which oil lubricates in comparison to the undiluted state as mentioned. Using the pressure viscosity relationship available in the data map, the control unit detects that there is variation in viscosity due to dilution and the same is indicated in the form of a display. Upon further increase in the level of dilution the control unit checks for the viscosity and in case the level of dilution is such that lubrication of parts of engine is no longer possible, the same is indicated as a warning in the vehicle. By use of the above mentioned method it is now possible to detect oil dilution in engine and thereby prevent damage to the components of the engine.
[0010] ‘Adapted’ or ‘arranged’, in the context of the instant disclosure, refers to the technical capability or the technical capacity of a component, in relation to which the term ‘adapted’ or ‘arranged’ is used, to carry out or executed a specified action or actions, upon the requirement of the specified action or actions to be carried out or executed. Moreover, the usage of the term ‘adapted’ or ‘arranged’ here, is in reference with the normal technical capability or technical capacity of the component, imparted by the design or the structure or the composition of the component, and not in reference with any special or

extraneous capability or capacity, beyond the scope of the normal technical capability or technical capacity. Therefore there is a need to address this problem.
[0011]It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of oil used. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.

CLAIMS
We Claim:
1. A method of detecting oil dilution in an engine, said engine comprising
at least a flow path for flow of said oil, and said flow path comprising at
least one pressure switch, said method comprising :
receiving(100), by a control unit, a coolant temperature of an engine as an input;
checking(102), by said control unit if said coolant temperature corresponds to an engine operating temperature;
receiving(104), by said control unit, a feedback value from at least one of said plurality of pressure switches.
comparing (106), by said control unit, said received feedback value of pressure with a corresponding value of viscosity stored in a data map; and
verifying (108), by said control unit if said value of viscosity corresponds to oil dilution.
2. The method of claim 1, further comprising indicating on a display device
if said verified value corresponds to oil dilution.