Stochastic pre-ignition prediction and mitigation systems and methods

1. An engine control system for a vehicle, comprising:

a timer module that tracks a period of operation of an engine where vacuum within an intake manifold is less than a first predetermined vacuum;

a stochastic pre-ignition (SPI) mitigation module that generates an SPI signal when the period is greater than a predetermined period and the vacuum is less than a second predetermined vacuum,

wherein the second predetermined vacuum is less than the first predetermined vacuum; and

a boost control module that reduces output of a turbocharger in response to the generation of the SPI signal.

2. The engine control system of claim 1 further comprising a second timer module that tracks a period of the reduction of the output of the turbocharger,

wherein the boost control module disables the reduction of the output of the turbocharger when the period of the reduction is greater than a second predetermined period.

3. The engine control system of claim 1 wherein the second predetermined vacuum corresponds to ambient air pressure.

4. The engine control system of claim 1 further comprising a fuel control module that selectively richens fueling in response to the generation of the SPI signal.

5. The engine control system of claim 1 further comprising a fuel control module that selectively adjusts fuel injection timing in response to the generation of the SPI signal.

6. The engine control system of claim 1 further comprising a spark control module that selectively adjusts spark timing in response to the generation of the SRI signal.

7. The engine control system of claim 1 further comprising:

a fuel control module that selectively adjusts fueling in response to the generation of the SRI signal; and

a spark control module that selectively advances spark timing in response to the generation of the SPI signal.

8. The engine control system of claim 7 further comprising a second timer that tracks a period of the reduction in the output of the turbocharger,

wherein, when the period of the reduction is greater than a second predetermined period:

the boost control module disables the reduction in the output of the turbocharger;

the fuel control module disables the adjustment of the fueling; and

the spark control module disables the advancement of the spark timing.

9. The engine control system of claim 1 wherein the predetermined period is greater than 5 minutes.

10. An engine control system for a vehicle, comprising:

a timer module that tracks a period of operation of an engine where a pressure within an intake manifold is less than a first predetermined pressure;

a stochastic pre-ignition (SPI) mitigation module that generates an SPI signal when the period is greater than a predetermined period and the pressure transitions from less than the first predetermined pressure to greater than a second predetermined pressure,

wherein the second predetermined pressure is greater than the first predetermined pressure; and

a boost control module that reduces output of a turbocharger in response to the generation of the SPI signal.

11. An engine control method for a vehicle, comprising:

tracking a period of operation of an engine where vacuum within an intake manifold is less than a first predetermined vacuum;

generating a stochastic pre-ignition (SPI) signal when the period is greater than a predetermined period and the vacuum is less than a second predetermined vacuum,

wherein the second predetermined vacuum is less than the first predetermined vacuum; and

reducing output of a turbocharger in response to the generation of the SPI signal.

12. The engine control method of claim 11 further comprising:

tracking a period of the reduction of the output of the turbocharger; and

disabling the reduction of the output of the turbocharger when the period of the reduction is greater than a second predetermined period.

13. The engine control method of claim 11 wherein the second predetermined vacuum corresponds to ambient air pressure.

14. The engine control method of claim 11 further selectively richening fueling in response to the generation of the SPI signal.

15. The engine control method of claim 11 further comprising selectively adjusting fuel injection timing in response to the generation of the SPI signal.

16. The engine control method of claim 11 further comprising selectively adjusting spark timing in response to the generation of the SPI signal.

17. The engine control method of claim 11 further comprising:

selectively adjusting fueling in response to the generation of the SPI signal; and

selectively advancing spark timing in response to the generation of the SPI signal.

18. The engine control method of claim 17 further comprising:

tracking a period of the reduction in the output of the turbocharger; and

when the period of the reduction is greater than a second predetermined period:

disabling the reduction in the output of the turbocharger;

disabling the adjustment of the fueling; and

disabling the advancement of the spark timing.

19. The engine control method of claim 11 wherein the predetermined period is greater than 5 minutes.

20. An engine control method for a vehicle, comprising:

tracking a period of operation of an engine where a pressure within an intake manifold is less than a first predetermined pressure;

generating a stochastic pre-ignition (SPI) signal when the period is greater than a predetermined period and the pressure transitions from less than the first predetermined pressure to greater than a second predetermined pressure,

wherein the second predetermined pressure is greater than the first predetermined pressure; and

reducing output of a turbocharger in response to the generation of the SPI signal.