Method of controlling the start-up of an internal combustion engine

1. A method of controlling the startup of an indirect injection internal combustion engine ( 28 ), said indirect injection internal combustion engine comprising:

a plurality of cylinders ( 12 ),

a piston ( 14 ) in each of said cylinders sliding between a bottom dead center ( 30 ) and a top dead center ( 32 ),

a crankshaft whose rotational movement is linked with the sliding movement of each of the pistons ( 14 ),

an inlet valve ( 16 ) and an exhaust valve ( 18 ) moving between an open position and a closed position, and being associated with each of the cylinders ( 12 ),

an inlet manifold ( 20 ) associated with said each of the cylinders ( 12 ) and connected by an intermediary of said inlet valve ( 16 ) associated with said each of the cylinders, and

an injector ( 26 ) associated with said each of the cylinders ( 12 ) for injecting fuel into the inlet manifold associated with said each of the cylinders,

ignition means ( 24 ) associated with said each of the cylinders ( 12 ) for igniting the fuel contained in said each of the cylinders ( 12 ),

a crankshaft position sensor ( 2 ) comprising a fixed part ( 4 ) and a target ( 6 ) linked with the crankshaft, said target comprising a reference index ( 10 ) detectable by the fixed part ( 4 ),

said method comprising the following steps:

commanding starting of the rotation of the crankshaft from a starting position (P 1 , P 2 , P 3 , P 4 ) of the engine,

detecting the rotation of the crankshaft,

selecting a group of cylinders and for each of the selected group of cylinders, detecting the reference index ( 10 ) less than a half-turn of the crankshaft before the piston ( 14 ) associated with it reaches the top dead center ( 32 ),

commanding the injectors ( 26 ) associated with the selected group of cylinders such that the injectors finish injecting fuel into the inlet manifolds ( 20 ) associated with the selected group of cylinders before the crankshaft has turned through 75 degrees with respect to the starting position (P 1 , P 2 , P 3 , P 4 ) of the engine, such that at least one of the inlet valves ( 16 ) associated with the selected group of cylinders changes ( 16 b ) from the open position to the closed position,

detecting the reference index ( 10 ),

commanding the ignition means ( 24 ) to ignite said each of the selected cylinders at a time determined as a function of the detecting of the reference index ( 10 ) and substantially corresponding to an arrival at the top dead center ( 32 ) of the piston ( 14 ) associated with igniting said each of the selected cylinders, wherein said method is free of any use of a camshaft position sensor.

2. The method as claimed in claim 1 , wherein the target ( 6 ) of the sensor ( 2 ) is provided with a plurality of marks ( 8 ) detectable by the fixed part ( 4 ) and the detecting the reference index comprises consecutively detecting a certain number of the marks ( 8 ).

3. The method as claimed in claim 2 , wherein the target ( 6 ) of the sensor is provided with at least thirty marks ( 8 ) detectable by the fixed part ( 4 ) and the rotation of the engine is detected by the detection of 3 to 10 marks consecutively.

4. The method as claimed in claim 1 , wherein said step of commanding the injectors comprises issuing a command for the injection ( 26 ) of fuel and stopping the issuing of the command before at least one of the inlet valves ( 16 ) of the selected group of cylinders changes ( 16 a ) from the closed position to the open position.

5. The method as claimed in claim 1 , wherein the engine ( 28 ) comprising four cylinders, and said step of commanding the injectors ( 26 ) is stopped before the crankshaft has turned through 75 degrees with respect to the starting position (P 1 , P 2 , P 3 , P 4 ) of the engine.

6. The method as claimed in claim 2 , wherein said step of commanding the injectors is stopped before at least one of the inlet valves ( 16 ) of the selected group of cylinders changes ( 16 a ) from the closed position to the open position.

7. The method as claimed in claim 3 , wherein said step of commanding the injectors is stopped before at least one of the inlet valves ( 16 ) of the selected group of cylinders changes ( 16 a ) from the closed position to the open position.

8. The method as claimed in claim 2 , wherein the engine ( 28 ) comprising four cylinders, and said step of commanding the injectors ( 26 ) is stopped before the crankshaft has turned through 75 degrees with respect to the starting position (P 1 , P 2 , P 3 , P 4 ) of the engine.

9. The method as claimed in claim 3 , wherein the engine ( 28 ) comprising four cylinders, and said step of commanding the injectors ( 26 ) is stopped before the crankshaft has turned through 75 degrees with respect to the starting position (P 1 , P 2 , P 3 , P 4 ) of the engine.

10. The method as claimed in claim 1 , wherein the engine ( 28 ) comprising four cylinders, and said step of commanding the injectors ( 26 ) is stopped before the crankshaft has turned through 75 degrees with respect to the starting position (P 1 , P 2 , P 3 , P 4 ) of the engine.

11. A method of controlling the startup of an indirect injection internal combustion engine ( 28 ), said indirect injection internal combustion engine comprising:

a plurality of cylinders ( 12 ),

a piston ( 14 ) in each of said cylinders sliding between a bottom dead center ( 30 ) and a top dead center ( 32 ),

a crankshaft whose rotational movement is linked with the sliding movement of each of the pistons ( 14 ),

an inlet valve ( 16 ) and an exhaust valve ( 18 ) moving between an open position and a closed position, and being associated with each of the cylinders ( 12 ),

an inlet manifold ( 20 ) associated with said each of the cylinders ( 12 ) and connected by an intermediary of said inlet valve ( 16 ) associated with said each of the cylinders, and

an injector ( 26 ) associated with said each of the cylinders ( 12 ) for injecting fuel into the inlet manifold associated with said each of the cylinders,

ignition means ( 24 ) associated with said each of the cylinders ( 12 ) for igniting the fuel contained in said each of the cylinders ( 12 ),

a crankshaft position sensor ( 2 ) comprising a fixed part ( 4 ) and a target ( 6 ) linked with the crankshaft, said target comprising a reference index ( 10 ) detectable by the fixed part ( 4 ),

said method comprising the following steps:

commanding starting of the rotation of the crankshaft from a starting position (P 1 , P 2 , P 3 , P 4 ) of the engine,

detecting the rotation of the crankshaft,

selecting a group of cylinders and for each of the selected group of cylinders, detecting the reference index ( 10 ) less than a half-turn of the crankshaft before the piston ( 14 ) associated with it reaches the top dead center ( 32 ),

commanding the injectors ( 26 ) associated with the selected group of cylinders such that the injectors finish injecting fuel into the inlet manifolds ( 20 ) associated with the selected group of cylinders before the crankshaft has turned through 75 degrees with respect to the starting position (P 1 , P 2 , P 3 , P 4 ) of the engine, such that at least one of the inlet valves ( 16 ) associated with the selected group of cylinders changes ( 16 b ) from the open position to the closed position,

detecting the reference index ( 10 ),

commanding the ignition means ( 24 ) to ignite said each of the selected cylinders at a time determined as a function of the detecting of the reference index ( 10 ) and substantially corresponding to an arrival at the top dead center ( 32 ) of the piston ( 14 ) associated with igniting said each of the selected cylinders, wherein the crankshaft position sensor is the only position sensor used by said method.