Control of manifold vacuum in skip fire operation
AssigneeTula Technology, Inc.
InventorsSteven E. Carlson, Xin Yuan, Joshua P. Switkes, Louis J. Serrano
Life of this patent
Estimating the term…
Abstract
A variety of methods and arrangements are described for selectively reducing intake manifold pressure in a skip fire engine control system. In some embodiments, a throttle is adjusted to generate a manifold vacuum, which is used for various applications, including but not limited to purging a fuel vapor canister, reducing pressure within a brake vacuum booster reservoir and/or venting gas from a crankcase interior. An engine firing fraction is increased to help maintain a desired torque level. Other techniques for reducing the intake manifold pressure are also described, such as applications involving a return to idle.
Claims23
A method of selectively reducing intake manifold pressure in a skip fire engine control system to help purge a fuel vapor canister, reduce pressure within a brake vacuum booster reservoir or vent gas from a crankcase interior, the method comprising:
- operating an engine in a skip fire manner to generate a desired torque level using a throttle set at a substantially open position;
- further closing the throttle to reduce the intake manifold pressure in order to perform a manifold vacuum-related process selected from the group consisting of 1) purging the fuel vapor canister;
- 2) reducing pressure within a brake vacuum booster reservoir;
- and 3) venting gas from the crankcase interior;
- increasing an engine firing fraction to help maintain the desired torque level;
- and
- after the manifold vacuum-related process has been performed, returning the throttle to the substantially open position and decreasing the firing fraction.
A method of selectively reducing intake manifold pressure in a skip fire engine control system to prepare for a return to idle, the method comprising:
- operating an engine of a vehicle in a skip fire manner to generate a desired torque level using a throttle set at a substantially open position;
- detecting that the engine will return to idle;
- closing the throttle to help reduce the intake manifold pressure;
- increasing an engine firing fraction to help reduce the intake manifold pressure;
- and
- adjusting an engine parameter to help maintain the desired torque level.
An engine controller used to control an internal combustion engine, the engine controller comprising:
- a power train parameter adjusting module that is arranged to:
- set the throttle at a substantially open position to help deliver a desired torque level;
- further close the throttle to reduce the intake manifold pressure in order to perform a manifold vacuum-related process selected from the group consisting of 1) purging the fuel vapor canister;
- 2) reducing pressure within a brake vacuum booster reservoir;
- 3) venting gas from the crankcase interior;
- and 4) preparing for a return to idle;
- and
- return the throttle to the substantially open position after the manifold vacuum-related process has been at least substantially completed;
- and
- a firing fraction calculator that is arranged to:
- generate a firing fraction that is used to operate working chambers of the engine in a skip fire manner and that helps deliver the desired torque level;
- and
- adjust the firing fraction in order to help perform the manifold vacuum-related process.
A computer readable storage medium that includes executable computer code embodied in a tangible form operable to selectively reduce intake manifold pressure in a skip fire engine control system wherein the computer readable medium includes:
- executable computer code for setting the throttle at a substantially open position to help deliver a desired torque level;
- executable computer code for further closing the throttle to reduce the intake manifold pressure in order to perform a manifold vacuum-related process selected from the group consisting of 1) purging the fuel vapor canister;
- 2) reducing pressure within a brake vacuum booster reservoir;
- 3) venting gas from the crankcase interior;
- and 4) preparing for a return to idle;
- executable computer code for returning the throttle to the substantially open position after the manifold vacuum-related process has been at least substantially completed;
- and
- executable computer code for generating a firing fraction that is used to operate working chambers of the engine in a skip fire manner and that helps deliver the desired torque level;
- and
- executable computer code for adjusting the firing fraction in order to help perform the manifold vacuum-related process.
Dependencies are inferred from the claim text.