CLIAMS:We claim:
1. A method to reduce a starting time period of an engine (12) in a vehicle, said method comprising :
-calculating an initial starting time period taken by said engine to reach a threshold speed;
-dividing said initial starting time period into a plurality of individual time periods in dependence with a speed of said engine;
-varying at least two parameters in at least one said individual time period;
- reducing said individual time period in dependence with said variation in said at least two parameters;
-calculating said reduced individual time period;
-reducing said starting time period of said engine in dependence with said reduced individual time period.
2. The method claimed in claim (2), wherein said at least two parameters can be chosen from a group of parameters like an injection pressure, injection timing, a starting power or the like.
3. An electronic control unit (10) to reduce a starting time of an engine (12) in a vehicle, said electronic control unit (10) comprising :
-a calculating means (14) adapted to calculate an initial starting time period taken by said engine to reach a threshold speed;
-a dividing means (16) adapted to divide said initial starting time period into a plurality of individual time periods in dependence with a speed of said engine (12);
-a varying means (18) adapted to vary at least two parameters of said engine (12);
-a reducing means (20) adapted to reduce said individual starting period in dependence with said variation in said at least two parameters;
said calculating means (14) calculates reduced individual time period and said reducing means (20) reduces said starting time period of said engine in dependence with said reduced individual time period.
,TagSPECI:Field of the invention
[001] This invention relates to a method to reduce a starting time of an engine.
Background of the invention
[002] Operating states of diesel engine refers to the regimes of speed and load that any engine operates at a given instant in time. The speed and load regimes are classified as low, intermediate and high and it will be possible to define unique boundaries of speed and load and corresponding environmental conditions that the engine experiences in each operating state. Operating states of engine can be broadly classified into 5 groups: Start State, Low Idle State, Part Load & Full Load State, and High Idle State. Starting an engine covers the process from closing the ignition circuit, cranking the engine to defined speed using starter motor, initiation of combustion to sustained combustion, acceleration of engine speed till signaling engine start is completed or till self sustained stable operation of the engine.

[003] Many techniques are known in the state of art method of reducing a starting time of an engine of a vehicle.
[004] An US granted patent 7668706 discloses a method for simulating the driving behavior of vehicles on a test stand. A simulation model calculates simulation values of variables which are representative of the driving state of the vehicle, in that the reaction of the vehicle to the behavior of the engine and the values of the variables are calculated.

Brief description of the accompanying drawings
[005] An exemplifying embodiment of the invention is disclosed in detail in the description and illustrated in the accompanying drawings:
[006] Figure 1 illustrates a block diagram of an electronic control unit according to one embodiment of the invention; and
[007] Figure 2 illustrates a flowchart of a method of working of a device according to one embodiment of the invention.
Detailed description of the invention:
[008] Figure 1 illustrates a block diagram of an electronic control unit 10 to reduce a starting time of an engine 12 in a vehicle according to one embodiment of the invention. The electronic control unit 10 comprises a calculating means 14 adapted to calculate an initial starting time period taken by the engine 12 to reach a threshold speed. The electronic control unit 10 comprises a dividing means 16 adapted to divide the initial starting time period into a plurality of individual time periods in dependence with a speed of the engine 12. The electronic control unit 10 also comprises a varying means 18 adapted to vary at least two parameters of the engine 12 .The electronic control unit 10 also comprises a reducing means 20 adapted to reduce the individual starting period in dependence with the variation in at least two parameters. The calculating means 14 calculates reduced individual time period and the reducing means 20 reduces the starting time period of the engine 12 in dependence with the reduced individual time period.
[009] Figure 2 illustrates a flowchart of a method to reduce a starting time of an engine 12 in a vehicle according to one embodiment of the invention. In step S1 an initial starting time period taken by the engine 12 to reach a threshold speed is calculated. In step S2, the initial starting time period is divided into a plurality of individual time periods in dependence with a speed of the engine 12. In step S3, at least two parameters are varied in at least one individual time period. In step S4, the individual time period is reduced in dependence with the variation in the at least two parameters. In step S5, the reduced individual time period is calculated and the starting time period is of the engine reduced in dependence with the reduced individual time period.

[0010] The initial starting time period can be divided into a plurality of stages associated with plurality of individual time periods. The plurality of stages of an engine 12 can be a cranking stage, a combustion stage, an engine speed acceleration stage or the like. For instance, if the starting of the engine 12 is divided into three stages, in the first stage which is a cranking stage, the time required for cranking the engine 12 from rest to a minimum starting speed is considered. The power required for cranking the engine 12 from rest to the minimum starting speed will be provided by a battery. In the second stage which is a combustion stage, the engine speed increases further and the time required for initial combustion and auto ignition is considered. In the third stage which is an engine speed acceleration stage, the time required for the injection of the fuel into the combustion chamber and till the speed of the engine 12 reaches a low idling speed is considered.
[0011] Initially, the calculating means 14 calculates an initial starting time period of the engine 12. The dividing means 16 divides the initial starting time period of the engine 12 into a plurality of individual time periods. For instance, if there are three individual time periods T1, T2, T3 associated with three individual starting stages of the engine 12, then the initial starting time period T taken for the engine 12 to start from the rest to the low idling speed will be the sum of the individual time periods (T1+T2+T3). The starting time period can be reduced by reducing at least one individual time period i.e., either T1 or T2 or T3 or (T1 and T2 and T3) by varying at least two parameters. The varying means 16 varies at least two parameters. The parameters of the engine 12 are selected from a group of parameters like an injection pressure or injection timing or a starting power or the like. For instance, considering at least three parameters P1, P2, P3 which will affect the starting time of the engine 12, the starting time period of the engine 12 can be reduced by varying the three parameters in a multiple ways. In one scenario, the parameter P1 is kept constant and the parameters P2, P3 will be changed to reduce the starting time of the engine 12 in at least one stage. In other scenario, all the parameters P1, P2, P3 will be changed to reduce the initial starting time period of the engine 12 in at least one stage. The reducing means 18 reduces the individual time period in at least one stage in dependence with the variation in at least two parameters. The calculating means 14 calculates the deviation in the individual time period in at least one stage . The calculating means 14 calculates reduced starting time period in dependence with the reduced individual time period in at least one stage. The electronic control unit 10 reduces the starting time of the engine 12 by reducing at least one individual time period in at least one stage. By varying the parameters as explained above, the electronic control unit 10 reduces the starting time of the engine 12.

[0012] For instance, the parameters like injection pressure, injection timing, starting power is considered. In first scenario, the injection pressure 300 bar is kept constant and the injection timing and the starting power is varied. Initially, the initial starting time period is calculated with injection pressure 300 bar and injection timing 1CrA and the starting power 2KW. Maintaining the injection pressure at 300 bar, the injection timing is varied from 1CrA-4CrA and the starting power from 2KW-2.7 KW. The individual time period is calculated with varied parameters. The deviation in the individual time period is calculated by the calculating means 14. In second scenario, the injection timing and the starting power is kept constant at 1CrA and 2 KW and the injection pressure is changed from 300 bar – 350 Bar. The calculating means 14 calculates the individual time period in dependence with the varied injection pressure. In third scenario, the injection pressure, the injection timings and the starting power are changed from 300 bar to 350 bar, from 1 CrA to4 CrA and from 2KW to 2.7KW respectively. The calculating means 14 calculates the individual starting time in dependence with the varied parameters. The electronic control unit 10 considers different calculated individual time periods and the deviations of the respective indidvual time period in different scenarios. The electronic control unit 10 calculates the starting time T of the engine 12 by considering the individual time period with maximum deviation.

[0013] The process explained above is repeated in different stages of the starting of the engine 12. The starting time of the engine 12 is reduced by reducing at least one individual time period in at least one stage by varying at least two parameters.

[0014] With the electronic control unit 10 and the method operating the electronic control unit 10 disclosed above, a cost effective solution can be achieved. With the above method, the total starting time of the engine 12 can be reduced by reducing the individual time period in at least one stage of the starting of the engine 12.
[0015] It must be understood that the examples and embodiments of the components explained in the detailed description are only illustrative and do not limit the scope of the invention. The scope of this invention is only limited by the scope of the claims.