FIELD OF INVENTION:

This invention relates to a method for detecting a position of an internal combustion engine.

BACKGROUND OF THE INVENTION:

The fuel injection and the ignition of the fuel in a cylinder of an internal combustion engine has to occur at a precise time in relation to the stroke of the associated cylinder in order to meet emission, performance and efficiency requirements. Typically the fuel is injected/ignited when the associated cylinder is at or around a top dead centre (TDC) of a compression stroke.

The position of the crank shaft is monitored to determine the engine position. One method to measure crankshaft position is to link a target wheel to the crankshaft and sense the target wheel rotation. This target wheel includes features which allow individual revolutions of the wheel and fractions thereof to be sensed.
US 20090056429A1 discloses one method to detect the position of the engine.

OBJECT OF THE INVENTION:

The object of the invention is to detect a position of an internal combustion engine in advance so that precise injection and ignition of the fuel can take place at the earliest and at the right position of the engine.

ADVANTAGES OF THE INVENTION:

Early detection of the engine position helps in injecting/igniting the fuel at right engine position to reduce emissions during the starting of the engine. This increases the fuel efficiency of the engine.

The invention makes use of the existing sensors and the existing ECU without needing any additional hardware components.

BRIEF DESCRIPTION OF THE DRAWINGS:-
Fig. 1 shows a schematic of the invention
Fig. 2 shows a flow chart of the invention

DETAILED DESCRITPION OF THE INVENTION:
Shown in fig. 1 is a schematic of the invention. Shown in fig. 1 is an electronic control unit 10 adapted to receive an input signal 12 which is indicative of an user intention to start the engine; a crank shaft position signal 14 and a camshaft position signal 16, to generate a timing signal 18 to inject/ignite the fuel in a cylinder of the engine which is not shown in the fig. 1.

Shown in fig. 2 is a flow chart showing the method to perform the invention. The steps listed in the flow chart are run by the electronic control unit 10 which is controlling the engine. In step 10, the method determines an user intention to start the engine. The triggers to determine the user intention to start the engine may comprise: detection of opening of the vehicle door, insertion of an ignition key in the ignition switch, starting of communication of messages between different electronic control units in the vehicle, pressing of an ignition switch if the vehicle has keyless entry etc. These triggers are listed only as examples and there may be different triggers using a combination of events occurring in the vehicle. In step 12, the method operates the starter motor to rotate the crank shaft. As the crank shaft starts rotating, the crank shaft position sensor starts generating crank shaft position signal and camshaft position sensor starts generating the camshaft position signal which typically comprises a plurality of pulses. A reference pulse is generated by the crank shaft position sensor when a reference cylinder reaches a known position. This known position is typically a TDC during the compression stroke of the reference cylinder. In steps 16 the method detects the reference pulse in the crank shaft position signal along with the camshaft position signal details and in step 18 stores the position information of the engine with respect to the reference signal. In step 20, the method switches off the starter motor. When the starter motor is stopped, the crank shaft may rotate still for a short duration because of its momentum. When the crank shaft stops rotating, the position information of the engine is updated and stored.

In step 22, the method waits for further inputs from the user to actually start the engine. The further inputs may be turning the ignition key to the cranking position in the switch or any other trigger which is indicative of user's intention to actually start the engine. Once the trigger to start the engine is detected, the starter motor is started again. The method makes use of the stored engine position which was stored in step 18. As the engine position is already known, the injection and the ignition of the fuel can take place as soon as the engine is cranked.

With the present invention, it is possible to detect the position of the engine much earlier than the actual start of the engine by the user. The position of the engine is detected by monitoring a single rotation of the crank wheel. The position of the engine is determined without any fuel injection/ignition into the cylinder thereby avoiding the emissions and also avoiding the wastage of the fuel. The engine position is determined before the actual start of the engine and the same is used when the user actually starts the engine.

WE CLAIM:

1. A method to detect phase of an engine in a vehicle, the said method comprising the steps:
- detecting an user intention to start the engine
- operating a starter motor coupled to the said engine
- detecting a reference signal from a crank shaft position sensor to determine the phase of the said engine and storing the position information of the said engine
- stopping the said starter motor after storing the said position information of the engine
- waiting for user input to start the said engine
- using the said position information of the said engine to inject and/or ignite the fuel during the starting of the said engine.

2. A method according to claim 1 wherein detecting the user intention to start the engine may comprise detecting opening of a door of the vehicle

3. A method according to claim 1 wherein detecting the user intention to start the engine may comprise detecting the insertion of an ignition key in an ignition switch in the vehicle.

4. A method according to claim 1 wherein detecting the user intention to start the engine may comprise detecting the starting of communication of messages between different electronic control units in the vehicle,

5. A method according to claim 1 wherein detecting the user input to start the engine may comprise detecting the ignition key in cranking position in ignition switch in the vehicle

6. A method according to claim 1 wherein detecting the user input to start the engine may comprise detecting the pressing of an ignition switch in the vehicle

7, A method according to claim 1 wherein a transfer program transfers and authorizes a software program from a source computer to a target computer

8. An electronic control unit (10) adapted to receive
- an input signal (12) which is indicative of an user intention to start the engine;
- a crank shaft position signal (14);
to generate a timing signal 16 to inject and/or ignite the fuel in a cylinder of an engine.