CLIAMS:We claim:
1. A method for assisting in cold start of an engine (101), said method comprising the following steps,
detecting at least one engine operation parameter (S1);
determining a current state of engine operation as cold start condition from said at least one engine operation parameter (S2);
operating purge valve (105) to supply the additional quantity of air required during cold start condition (S3); and
assisting in fuel supply for cold start with fuel vapors purged from a carbon canister (103) (S4).
2. A method as claimed in claim (1) wherein said engine (101) operation parameter for activation or deactivation of said purge valve (105) is selected from a group comprising engine speed signal (Pa), ignition pulse (Pb), intake manifold pressure signal (Pc), throttle position signal (Pd) and engine temperature (Pe), air temperature (Pf) and air fuel ratio or oxygen content from lambda sensor (Pg) .
3. A method as claimed in claim (1) wherein said cold start of the engine (101) is assisted by said purge valve (105).
4. An engine control unit (107) of a vehicle, said engine control unit (107) (ECU) adapted to detect at least one engine operation parameter and determine a current state of engine operation as cold start from said parameter; said ECU further adapted to control a purge valve (105) and supply the additional air required for the cold start of engine (101) and assist in fuel supply with fuel vapors purged from said carbon canister (103).
5. An engine control unit (107) as claimed in claim (4) wherein said engine operation parameter is selected from a group comprising engine speed signal (Pa), ignition pulse (Pb), intake manifold pressure signal (Pc), throttle position signal (Pd) and engine temperature (Pe), air temperature (Pf) and air fuel ratio or oxygen content from lambda sensor (Pg) .
6. A device (100) for assisting cold start of an engine (101), said device (100) comprising,
a carbon canister (103) adapted to capture fuel vapors from a fuel tank (102);
a purge valve (105) adapted to supply air to the air intake path(106), said air adapted to flow via said carbon canister (103) to purge the captured fuel vapors; and
a control unit (107)adapted to operate said purge valve (105) during a cold start condition to supply the additional required air and assist in fuel supply with fuel vapors purged from said carbon canister (103) .
7. A device (100) as claimed in claim (5) wherein said purge valve (105) operates as a choke. ,TagSPECI:The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the invention:
[001] The invention relates to device and method for engine control. Particularly the invention relates to device and method for assisting engine operation during cold start conditions.

Background of the invention:
[002] In the present vehicles, spark ignition engine needs to be assisted with additional air and rich fuel mixture manually during cold start conditions. Normally in an electronic fuel injection engines, this is done though an idle speed actuator in the system or opening more throttle in case of an engine with electronic throttle control. Both the solutions increases the system cost. The other approach is with a device known as a choke which is mechanically operated. In such a device there is a possibility of running the engine continuously with rich fuel even at warm engine running condition, if user fails to deactivate the mechanism. This will result in unnecessary fuel consumption, adding up to running cost.

[003] For gasoline vehicles, due to increase in ambient temperature, the fuel in the tank may get evaporated. In systems with electronic fuel injection systems, there may be a solenoid purge valve to purge the fuel vapors from the tank into the intake manifold. Presently the purge valve is operated at predetermined conditions to fulfill the target evaporative emission legislation requirement. In some cases, if the carbon canister used for capturing fuel vapors can no longer adsorb more fuel vapors, the purge valve is opened allowing the ambient air to pass through the carbon canister and purge the fuel vapors into the air intake path of the engine.

[004] JP-2012026332 discloses one such evaporative fuel purging system for a vehicle with electronic fuel injection system.

Brief description of the invention:
[005] The present vehicles include a plurality of different valves performing different functions. It is possible to achieve the desired outcome of different valves using a single valve. In accordance with this invention a solenoid purge valve in the vehicle is adapted to be used to assist during cold start conditions, thus eliminating the need for a separate choke or an additional electronic valve.

[006] A method for operating of a vehicle engine during cold start condition is envisaged in accordance with this invention. The method comprising the steps of detecting at least one engine operation parameter to determine a current state of engine operation as cold start condition; operating a purge valve to supply the additional quantity of air and fuel vapors purged from a carbon canister to assist in cold start. And also to determine the proportion of fuel vapors purged and correcting the fuel quantity necessary to maintain the target stoichiometric ratio through the onboard fuel injector during engine start

Brief description of the drawings:
[007] The different embodiments of the invention are described with reference to the following accompanying drawings:
[008] Fig. 1 illustrates a schematic diagram representing a device for assisting cold start of an engine in a vehicle in accordance with one embodiment of the invention; and
[009] Fig. 2 illustrates a flowchart representing the method of assisting cold start of an engine in a vehicle in accordance with one embodiment of the invention.

Detailed description of the embodiments:
[0010] Fig. 1 illustrates a schematic diagram representing a device (100) for assisting cold start of an engine (101) in a vehicle in accordance with one embodiment of the invention.

[0011] The device (100) for assisting cold start of an engine (101) comprises a carbon canister (103) adapted to capture fuel vapors from a fuel tank (102). A purge valve (105) is adapted to supply air from ambient to the air intake path (106). The air supplied to the engine (101) on opening of the purge valve (105) flows via the carbon canister (103) to purge the captured fuel vapors. During the cold start condition, a control unit (107) is adapted to operate the purge valve (105) to supply the additional quantity of air and additional fuel in form of the fuel vapors purged from said carbon canister (103). The purge valve (105) operates as a choke to assist in cold starting of the vehicle, thus, eliminating the need for a separate choke or an additional electronic valve.

[0012] Fig. 2 illustrates a flowchart representing the method of assisting cold start of an engine (101) in a vehicle in accordance with one embodiment of the invention.

[0013] The method for assisting cold start of an engine (101) comprises the steps of detecting at least one engine operation parameter (S1) to identify a current state of engine operation as cold start condition (S2). On detection of the cold start condition of the engine (101) the purge valve (105) is operated to supply the additional quantity of air and fuel in form of fuel vapors purged from a carbon canister (103) (S4). The engine operation parameter is selected from a group comprising engine speed signal (Pa), ignition pulse (Pb), intake manifold pressure signal (Pc), throttle position signal (Pd), engine temperature (Pe), air temperature (Pf), and air fuel ratio or oxygen content from lambda sensor (Pg). A closed loop control to assist during cold start is possible by detecting at least one engine parameter and correcting air flow and fuel vapors from purge valve, fuel quantity from the fuel injector and ignition timing. The cold start of engine (101) is assisted by the purge valve (105) and the need for a choke or an additional electronic valve is eliminated.

[0014] It is envisaged in accordance with this invention, an engine control unit (107) (ECU) of a vehicle adapted to detect a at least one engine operation parameter and determine a current state of engine operation as cold start from the parameter and further operate a purge valve (105) and supply the additionally required air and fuel in form of fuel vapors purged from said carbon canister (103).

[0015] An engine (101) is supplied with fuel from a fuel tank (102). Due to ambient temperature, the fuel in the tank may evaporate. In order to recover the fuel that is evaporated, the fuel vapors from the tank are allowed to pass through a carbon canister (103) where the fuel vapors get absorbed. An air flow path is provided to the carbon canister (103) from the air filter (108). A purge control valve (105) is positioned between the carbon canister (103) and the intake air path (106), so that it can be operated to selectively allow the ambient air and evaporated fuel vapors to flow from the carbon canister (103) to purge into the intake air path (106) downstream of the throttle valve (104) of the engine (101). The purge valve (105) is typically solenoid actuated or in some cases it can be a linear or rotary actuator. A control unit (107) receives inputs from various sensors in the vehicle corresponding to different engine control parameters. The control unit (107) identifies the current state of engine operation based on these parameters. If the control unit (107) identifies the present mode of operation of engine (101) as cold start condition, then the control unit (107) actuates the solenoid operated purge valve (105). On actuation of the purge valve (105), the air from the ambient and the fuel vapors from the carbon canister (103) are purged. The purged fuel vapors along with the air enter the intake path of the engine (101). The control unit (107) continues to keep the purge valve (105) in open condition or in a predefined pattern which can be duty cycle based or linear or rotary steps until the engine (101) warms up. Thus, the additional air required during cold start condition is provided through the carbon canister (103). The fuel required for cold start is supplied by the fuel injectors (109) and is assisted by the fuel vapors purged from the carbon canister (103). The activation and deactivation of the purge valve (105) is controlled by the control unit (107) based on the engine speed calculated from ignition pulse or from manifold pressure signal or by crank speed sensor or any other means.

[0016] The engine control unit (107) of a vehicle is adapted to detect at least one engine operation parameter and determine a current state of engine operation as cold start condition. The ECU (107) determines the quantity of air and fuel required during cold start. The ECU is further adapted to control a purge valve (105) and supply the additional air required during the cold start of the engine (101) and assist in fuel supply with fuel vapors purged from said carbon canister (103). It also adjusts the fuel to be injected based on the amount of fuel vapors supplied to the engine (101) from the carbon canister (103).

[0017] The present device (100) eliminates the need for a separate choke or an additional electronic valve to supply additional air and fuel during cold start condition, thus reducing the cost. The purge valve (105) acts as the choke and supplies the additional quantity of air required during cold start. The fuel vapors purged from the carbon canister assist in the fuel supply by injector (109) to enable a cold start. This improves the fuel efficiency of the engine (101). Since the purge valve (105) is solenoid operated, the device (100) disclosed provides improved control on the fuel consumption in cold start condition.