FIELD OF INVENTION:-
The invention relates to design and development of cost effective cold start device to meet cold startability on engines with VE Distnbutor type fuel injection equipment.
PRIOR ART:-
During cold start of diesel engine injection timing for metered quantity of fuel plays an important role. Since engine and atmospheric temperature is low (unfavorable for burning fuel).Increase in emission levels can be observed due to incomplete combustion of fuel during cold start. The advancing the injection timing will result in increased amount of time available for preparedness of atomized fuel particles for combustion and hence better combustion of fuel can be realized. The cold start device is provided the feed back signal from engine control system for controlling of cold start device actuation period.
Currently available cold start acceleration devices in Distributor type fuel injection pump family such as mechanically actuated Cold start accelerator devices, hydraulically actuated settable, non-settable and Piston type Cold start accelerator devices are expensive and could not be offered as the cost effective solutions. New innovatively designed Integrated Cold start accelerator device (Integrated-KSB), functionally integrated with other components and developed to meet the minimum necessary functional requirements of the engine and cost target of the customer.
In the present invention, the cold start device unit is provided the feedback (water jacket temperature of engine) from Engine control system for controlling of cold start device actuation period.
OBJECT OF THE INVENTION:
The first object of the present invention is to develop an integrated Cold start device for distributor type fuel injection pump to meet the essential functional requirements of the engine.
It is another object of the present invention is to provide a system for determining a supply fuel to an Internal combustion engine with VE distributor type injection pump for a cold start device with a timer device.

It is another object of the invention is to provide a system for deternnining the supply fuel to an Internal combustion engine with VE distributor type injection pump for a cold start device having atleast two overflow orifices.
It is also another object of the invention is to provide a system for determining the supply fuel to an Internal combustion engine with VE distributor type injection pump for a cold start device with a control from a temperature sensitive element to operate atleast one of the two overflow orifices.
It is further another object of the invention is to provide a system for determining the supply fuel to an Internal combustion engine with VE distributor type injection pump for a cold start device with load sensitive to operate atleast one of the two overflow orifices.
It is further another object of the present invention is to provide a method for determining the supply fuel to an Internal combustion engine with VE distributor type injection pump for a cold start device with the above fuel supply system having a timer device, such that the injection timing is advanced relative to crank shaft position, as the engine speed increases.
BRIEF DESCRIPTION OF THE INVENTION:
The object of the invention is achieved by using a timer device cold start
advance unit.
In order to compensate for injection and ignition lag, the timer device piston can advance the distributor pumps injection timing, relative to the crankshaft position, as the engine speed increases.
The position of timer device piston is dependent on the internal pump chamber pressure, in turn directly proportional to speed of the engine.
On actuation of the integrated cold start device the overflow quantity of the pump is restricted and results in increase of chamber pressure. This will result in increase of

timer travel, i,e additional advance to achieve cold start-ability and sustainabilitV on engine.


DESCRIPTION OF INVENTION WITH REFERENCE TO DRAWINGS:
Now the invention is described herein relates to one of the preferred embodiments ( which illustrated in the following drawings:-
Fig.1 illustrates the Hydraulic circuit diagram of IKSB mounted on the pump (IKSB is with two throttle bores 0 1.1 and 0 0.2 mm) as per the invention.
Fig.2 illustrates Integrated Cold start advance device (IKSB) Characteristic curve on Fuel Injection Pump(FIP) and corresponding pressure curves.
Fig.3 illustrates the internal details of IKSB according to the invention.
Fig 4 illustrates the functionality of the Integrated Cold start device which mounted on to the fuel injection pump wherein the Integrated cold start device is ON during cold start and OFF during normal working of the engine. The working of the invention is described herein below.
Distributor type fuel injection pump consists, in built Feed pumps, which build up the pressure inside the pump chamber. Pressure in side the pump chamber is directly proportional to the pump r.p.m., mathematically represented as

Pump chamber pressure depends upon amount of leakage, amount of fuel flowing through over flow (Intentionally allowed to maintain the pump chamber temperature), pressure limit set by Pressure control valve, quantity injected per stroke, Quantity of fuel pumped by Feed pump per revolution. Thus mathematically,

Existing design of Hydraulic KSBs function up on the principle of blocking the Relief from PCV leading to early pressure build up in side the pump chamber. The present invention differs from current practices as it works on the principle of blocking / throttling the Overflow passage, leading to excess loading of PCV much earlier than that of normal functioning resulting in pressure building inside the pump chamber (in fig.2 AP).

In distributor type FIP, Injection advance directly depends upon the Hydraulic timer travel. Timer travel is realized as a function of internal pump chamber pressure (fig.2). During normal pump functioning as shown in fig.1, feed pump (14) Pumps fuel in to the pump internal chamber (15). Quantity of fuel fed in to the chamber is directly proportional to the pump revolution per minute, i.e., higher the r.p.m higher the quantity fed in to the Pump internal chamber (15). In normal Pumps overflow valve has a constant orifice, which allows fuel to flow out of the pump. That means at given Pump chamber pressure and temperature of fuel, overflow quantity is constant. During calibration Pump PCV (12) is configured for desired Pressure curve (From Eq.1, Pump chamber pressure is directly proportional to Pump r.p.m) with respect to Pump r.p.m. as shown in Fig2. This pressure curve (Normal pressure curve) is achievable because quantity of fuel draining through leakages (Q leak) will become negligible as quantity of fuel being pumped by feed pump (14) (fig.1) in to the pump internal chamber (15) (fig.1) increases with r.p.m of pump considerably.
As per the invention, an Integrated Cold Start Device (IKSB) is basically the integration of overflow valve with the inbuilt solenoid which can provide the freedom of modifying the overflow throttle based on requirement. According to the invention, the newly developed Integrated Cold Start Device IKSB as shown in fig.3 consists of,
1. Housing with 0 1.1 mm and 0 0.2 mm throttle holes.
2. Filter.
3. Rubber bonded Plunger.
4. Solenoid.
5. Terminal.
6. Return spring.
For achieving Cold start functionality on to FIP, IKSB have to be mounted on the Pump replacing overflow valve. While calibrating Pump PCV (2) (fig.1) is configured to give the normal pressure curve as shown in fig.2 with IKSB switched OFF. When IKSB is in OFF condition, the over flow from FIP will be from both 0 1.1mm and 0 0.2 mm throttles, i.e.. Rubber bonded plunger (3) lifted up by return spring (6) as shown in fig.4 and the fig.2 shows the normal timer travel and the timer travel with IKSB actuation. During normal pump functioning if the timer begins to travel at Ni r.p.m and pressure P1, requirement for achieving the timer advance

during cold start will be to achieve the pressure rise by amount of AP (as shown in fig.2). This is achieved by energizing the IKSB. When IKSB is ON, this closes the 0 1.1mm orifice. This results in to resection in the overflow passage leading to pressure buildup in the Pump chamber. As a result of this Timer advance is realized much earlier than the normal functioning.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a system of determining a supply fuel to an Internal combustion engine with VE distributor type injection pump for a cold start, wherein the said system comprises of housing with a first fuel overflow orifice, second fuel overflow orifice, and a rubber bonded plunger. The said rubber bonded plunger is provided for closing the second orifice, when the engine temperature sensitive element of the system is cold.
In the preferred embodiment of the present invention, the said rubber bonded plunger is operable by a feed back engine temperature sensitive element such that the element when cold push down the plunger against a spring pressure to close the second orifice, thereby advancing injection timing; and such that element when warm extends to push up the plunger to open the second orifice thereby retarding the injection timing.
The invention further includes the method of determining supply fuel to an internal combustion engine with the said system adapted for cold start which shall comprises of three steps, firstly setting the fuel overflow restriction in such a manner that the restriction of overflow increase with a decrease in engine temperature, secondly setting the chamber pressure in such a manner that the chamber pressure increases with increase in restriction of overflow; and thirdly modifying the fuel overflow restriction in such a manner that the restriction of overflow decreases with a rise in rotational speed of the engine.
In one aspect of the invention, an engine cold start system is hereby configured to
use a for restricting overflow immediately after a cold start

such that there is an increase in chamber pressure resulting in increased tinner travel
thus advancing injection timing and then afterwards start feedback control such that
restriction of overflow is decreased to the pressure for-retarding injection
timing.
In another aspect of the invention, the method of determining supply fuel to an internal combustion engine adapted for a cold start including a Load dependent timer advance or retard of injection timing shall comprises of three steps, firstly setting the fuel overflow restriction in such a manner that the restriction of overflow changes with change in the engine load; secondly, setting the chamber pressure in such a manner that the chamber pressure of overflow changes with change in overflow restriction; and thirdly setting the Timer advance in such a manner that the injection timing of timer advance changes with change in overflow restriction.
As per the invention, the said method is characterized in wherein the said overflow restriction change shall comprises of overflow restriction increases with increase in engine load.
As per the invention, the said method is characterized in wherein the said overflow restriction change shall comprises of overflow restriction decreases with increase in engine load.
As per the invention, the said method is characterized in wherein the said chamber pressure change shall comprises of chamber pressure of overflow increases with increase in overflow restriction.
As per the invention, the said method is characterized in wherein the said chamber pressure change shall comprises of chamber pressure of overflow decreases with decrease in overflow restriction.
As per the invention, the said method is characterized in wherein the said injection timing change of timer advance shall comprises of advancing of timer with increase in overflow restriction.

As per the invention, the said method is characterized in wherein the said injection timing change of timer advance shall comprises of retarding of timer with decrease in overflow restriction.
The method of determining supply fuel to an Internal combustion engine adapted for cold start device, reducing the pressure inside the FIP during engine shut-OFF inorder to reduce/minimize the residual quantity of fuel injection shall comprises of three steps, firstly setting the fuel overflow restriction in such a manner that the relief from restriction of overflow decreases Pump chamber pressure; secondly setting the pump chamber pressure in such manner that it drops to very low when this device is shut-OFF and fuel injection at pump shut-OFF is eliminated due to starvation in side the pump chamber.
Advantages of Invention:
integrated cold start device (IKSB) when compared with conventional Hydraulic valves, following are the advantages.
> Simple pressure control valve.
> Elimination of external pipes.
> Elimination of separate overflow valve.
> Elimination of separate casting.
> Elimination of pressure relief valve.
> Elimination of separate solenoid.
> Cost effective. (Costs only 20% compared to present device).
The objects, scope and description of the present invention has been given herein. However, it should be understood that the drawings and descriptions are indicative and illustrative for the purpose of explanation thereby including all variations and modifications within the spirit and scope of the invention to the extend as apparent to those skilled in the art covered in the application.

WE CLAIMS:
1. A system of determining a supply fuel to an Internal combustion engine with VE distributor type injection pump for a cold start, said system comprising of a first fuel overflow orifice, second fuel overflow orifice, and a rubber bonded plunger closing the second orifice when the temperature sensitive element of the system is cold.
2. A system of determining a supply fuel to an Internal combustion engine with VE distributor type injection pump for a cold start as claimed in claim 1, said system having atleast
a. a first overflow orifice,
b. a second overflow orifice, and
c. a rubber bonded plunger operable by a feed back engine temperature
sensitive element such that the element when cold push down the
plunger against a spring pressure to close the second orifice, thereby
advancing injection timing; and such that element when warm extends
to push up the plunger to open the second orifice thereby retarding the
injection timing.
3. A method of determining supply fuel to an internal combustion engine with the
system as claimed in claim 1 adapted for cold start comprises of steps:
a. setting the fuel overflow restriction in such a manner that the restriction
of overflow increase with a decrease in engine temperature;
b. setting the chamber pressure in such a manner that the chamber
pressure increases with increase in restriction of overflow;
c. modifying the fuel overflow restriction in such a manner that the
restriction of overflow decreases with a rise in rotational speed of the
engine.
4. The method of determining supply fuel to an internal combustion engine
adapted for a cold start including a Load dependent timer advance or retard of
injection timing comprises of steps:

a. setting the fuel overflow restriction in such a manner that the restriction
of overflow changes with change in the engine load;
b. setting the chamber pressure in such a manner that the chamber
pressure changes with change in overflow restriction;
c. setting the Timer advance in such a manner that the injection timing of
timer advance changes with change in overflow restriction.
5. The method of determining supply fuel to an internal combustion engine adapted for a cold start including a Load dependent timer advance or retard of injection timing as claimed in claim 4a, wherein overflow restriction change comprises of restriction of overflow increases with increase in engine load.
6. The method of determining supply fuel to an internal combustion engine adapted for a cold start including a Load dependent timer advance or retard of injection timing as claimed in claim 4a, wherein overflow restriction change comprises of restriction of overflow decreases with increase in engine load.
7. The method of determining supply fuel to an internal combustion engine adapted for a cold start including a Load dependent timer advance or retard of injection timing as claimed in claim 4b, wherein chamber pressure change comprises of chamber pressure increases with increase in overflow restriction.
8. The method of determining supply fuel to an internal combustion engine adapted for a cold start including a Load dependent timer advance or retard of injection timing as claimed in claim 4b, wherein chamber pressure change comprises of chamber pressure decrease with decrease in overflow restriction.
9. The method of determining supply fuel to an internal combustion engine adapted for a cold start including a Load dependent timer advance or retard of injection timing as claimed in claim 4c, wherein injection timing change of timer advance comprises of advancing of timer with increase in overflow restriction.
10. The method of determining supply fuel to an internal combustion engine adapted for a cold start including a Load dependent timer advance or retard of

injection timing as claimed in claim 4c, wherein injection timing change of timer advance comprises of retarding of timer with decrease in overflow restriction.
11. The method as claimed in claim 3, further adapted for minimizing the residual fuel injection comprising the steps:-
a. setting further the fuel overflow restriction in such a manner that the
relief from restriction of overflow decreases Pump chamber pressure;
b. setting the pump chamber pressure in such manner that it drops to
very low when this device is shut-OFF and fuel injection at pump shut-
OFF is eliminated due to starvation in side the pump chamber.