Method for synchronizing injection with the engine phase in an electric injector controlled engine
In a method relating to an engine with n cylinders, fuel is injected in a predetermined order into the cylinders in a manner which is synchronized with the position of the pistons of the engine. The method includes the following steps after start-up: injection into m cylinders in a predetermined order of injection; measurement of engine speed and/or acceleration; continuation of injection in a predetermined order of injection if engine speed and/or acceleration exceed(s) a predetermined threshold; continuation of injection with a delay in the event of the contrary. The method can be used with respect to the start-up of a direct injection engine.
1. A method of synchronizing injection with engine phase in an engine with electronic injector control having n cylinders into which fuel is injected directly into each of the cylinders successively in a predetermined sequence, the fuel injection being synchronized with a position of a piston in the corresponding cylinder,
the method comprising the following steps, performed when the engine is started:
injecting fuel into m cylinders in the predetermined injection sequence when the corresponding pistons, put into motion by means of a starter, are at an end of a compression phase, m being determined in advance as a function of n,
measuring engine speed and/or acceleration,
continuing the injection in the predetermined sequence if the engine speed and/or acceleration exceed a predetermined threshold, the injection being synchronized with the engine phase in this case, and
continuing the injection with a phase change with respect to the preceding injections and with respect to the predetermined sequence, this phase change being a function of n and m, so that the injection is synchronized with the engine phase, in the contrary case,
wherein the method does not employ a camshaft sensor.
2. The synchronization method as claimed in claim 1 , characterized in that the engine speed and/or acceleration are measured after approximately one revolution of the engine.
3. The synchronization method as claimed in claim 1 , for an engine having an even number of cylinders, wherein m =n/2.
4. The synchronization method as claimed in claim 1 , wherein a second measurement of the engine speed and/or its acceleration is made after p further injections, p being determined in advance as a function of n and m, to check that the synchronization is correct.
5. The synchronization method as claimed in claim 4 , wherein the second measurement of the engine speed and/or its acceleration is made after two actual revolutions of the engine, in other words after n injections of fuel.
6. The synchronization method as claimed in claim 1 , wherein the position of the pistons in the cylinders of the engine is determined by a position sensor measuring an angular position of a corresponding engine flywheel.
7. The synchronization method as claimed in claim 1 , wherein a dose of fuel injected a first m injections being smaller than that used in subsequent injections.
8. The synchronization method as claimed in claim 2 , for an engine having an even number of cylinders, wherein m =n/2.
9. The synchronization method as claimed in claim 2 , wherein a second measurement of the engine speed and/or its acceleration is made after p further injections, p being determined in advance as a function of n and m, to check that the synchronization is correct.
10. The synchronization method as claimed in claim 3 , wherein a second measurement of the engine speed and/or its acceleration is made after p further injections, p being determined in advance as a function of n and m, to check that the synchronization is correct.
11. The synchronization method as claimed in claim 2 , wherein the position of the pistons in the cylinders of the engine is determined by a position sensor measuring an angular position of a corresponding engine flywheel.
12. The synchronization method as claimed in claim 3 , wherein the position of the pistons in the cylinders of the engine is determined by a position sensor measuring an angular position of a corresponding engine flywheel.
13. The synchronization method as claimed in claim 4 , wherein the position of the pistons in the cylinders of the engine is determined by a position sensor measuring an angular position of a corresponding engine flywheel.
14. The synchronization method as claimed in claim 5 , wherein the position of the pistons in the cylinders of the engine is determined by a position sensor measuring an angular position of a corresponding engine flywheel.
15. The synchronization method as claimed in claim 2 , wherein a dose of fuel injected in the first m injections is smaller than that used in subsequent injections.
16. The synchronization method as claimed in claim 3 , wherein a dose of fuel injected in the first m injections is smaller than that used in subsequent injections.
17. The synchronization method as claimed in claim 4 , wherein a dose of fuel injected in the first m injections is smaller than that used in subsequent injections.
18. The synchronization method as claimed in claim 5 , wherein a dose of fuel injected in the first m injections is smaller than that used in subsequent injections.
19. The synchronization method as claimed in claim 6 , wherein a dose of fuel injected in the first m injections is smaller than that used in subsequent injections.