Starting assistance method and device for an internal combustion engine

1. A starting assistance method for an internal combustion engine supplied with a fuel that may contain ethanol and including a fluid connection pipe between an intake manifold and a braking assistance device, the method comprising:

determining an engine temperature,

determining an outdoor air temperature,

preventing fluid communication through the pipe between the intake manifold and the braking assistance device for a given duration during a phase of starting the engine when the temperature of the engine is lower than a first threshold value and the outdoor air temperature is lower than a second threshold value, and

permitting fluid communication through the pipe between the intake manifold and the braking assistance device when the engine is rotating autonomously.

2. The method as claimed in claim 1 , wherein the pipe between the intake manifold and the braking assistance device permits fluid communication therethrough at rest.

3. The method as claimed in claim 1 , wherein the first threshold value of the engine temperature is able to be set within a range of values of between 10 and 30° C.

4. The method as claimed in a claim 1 , wherein the second threshold value of the outdoor temperature is able to be set within a range of values of between 0 and 10° C.

5. A starting assistance device for an internal combustion engine supplied with a fuel that may contain ethanol and including a fluid connection pipe between an intake manifold and a braking assistance device, the device comprising:

means for determining an engine temperature,

for determining an outdoor air temperature,

means for preventing fluid communication through the pipe between the intake manifold and the braking assistance device for a given duration during a phase of starting the engine when the temperature of the engine is lower than a first threshold value and the outdoor air temperature is lower than a second threshold value, and

means for permitting fluid communication through the pipe between the intake manifold and the braking assistance device when the engine is rotating autonomously.

6. The device, as claimed in claim 5 , further comprising:

a sensor for measuring the engine temperature,

a sensor for measuring the outdoor air temperature,

an electrically controlled valve arranged on the pipe connecting the intake manifold to the braking assistance device, able to prevent or permit fluid communication through the pipe depending on whether the valve is respectively closed or open, and

an electronic control device having a first input designed to receive the engine temperature information, a second input designed to receive the outdoor air temperature information and an output designed to drive the electrically controlled valve on the basis of the engine and outdoor air temperature information, and of threshold values relating to the engine and outdoor air temperatures, and

means for determining autonomous rotation of the engine.

7. The device as claimed in claim 6 , wherein the electrically controlled valve is in the open position by default.

8. The device as claimed in claim 6 , wherein the electrically controlled valve has a switching time of the order of 10 ms.

9. The device as claimed in claim 6 , wherein the electronic control device has at least one programmable electronic circuit.

10. An assembly comprising, a starting assistance device as claimed in claim 5 , the assembly further comprising an engine including an intake manifold, a braking assistance device, and a fluid connection pipe between the intake manifold and the braking assistance device.

11. The method as claimed in claim 2 , wherein the first threshold value of the engine temperature is able to be set within a range of values of between 10 and 30° C.

12. The device as claimed in claim 7 , wherein the electrically controlled valve has a switching time of the order of 10 ms.