Methods and systems for high pressure fuel pump cooling

Patent metadata

Field	Value
Publication number	US-10125715-B2
Application number	US-201715676440-A
Country	US
Kind code	B2
Filing date	Aug 14, 2017
Priority date	Sep 27, 2016
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

Methods and systems are provided for temperature control of a high pressure pump (HPP) of a direct injection system. When direct injection is disabled, the HPP and the associated direct injectors are intermittently operated when the HPP temperature rises above a modeled threshold temperature. The HPP and injectors are operated until the HPP temperature falls below the modeled threshold temperature.

First claim

The invention claimed is:

1. An engine system, comprising:
a fuel tank;
a port injector receiving fuel from the fuel tank via a lift pump;
a direct injector receiving fuel from the fuel tank via a high pressure fuel pump coupled downstream of the lift pump;
an engine coolant temperature sensor; and
a controller with computer readable instructions stored on non-transitory memory for:
during warm engine idling conditions,
fueling an engine cylinder via only the port injector while the direct injector and the high pressure pump are maintained disabled;
modeling a temperature of the high pressure fuel pump based at least on an output of the temperature sensor while the direct injector and the high pressure pump are held disabled; and
responsive to the modeled temperature exceeding a threshold, intermittently reactivating the direct injector and the high pressure pump.

2. The system of claim 1 , wherein the intermittently reactivating includes, while maintaining fueling via the port injector, fueling the engine cylinder via the direct injector with the high pressure pump enabled until the modeled temperature is lower than the threshold, an output of the high pressure pump adjusted based on a difference between the modeled temperature and the threshold.

3. The system of claim 2 , wherein the controller includes further instructions for:
estimating a drop in the modeled temperature during the selectively reactivating based on each of the output of the high pressure pump, a cooling effect of fuel flow through the direct injector, and a heat transfer function of the high pressure pump.

4. The system of claim 2 , wherein the controller includes further instructions for:
reducing fueling via the port injector while fueling the engine cylinder via the direct injector.

5. A method, comprising:
during an engine warm idling condition,
maintaining each of engine direct injectors and a high pressure fuel pump delivering fuel to the direct injectors disabled until a modeled temperature of the pump is higher than a threshold; and
then temporarily reactivating each of the engine direct injectors and the high pressure fuel pump until the modeled temperature is below the threshold.

6. The method of claim 5 , wherein the warm idling condition includes operating the engine below a threshold engine speed and supplying fuel to the engine via port injectors only.

7. The method of claim 6 , wherein the reactivating includes intermittently injecting fuel via the direct injectors and the high pressure fuel pump until the modeled temperature is below the threshold.

8. The method of claim 7 , wherein the reactivating includes adjusting a fuel pulse-width and interval of the intermittently injecting based on a difference between the modeled temperature and the threshold.

9. The method of claim 7 , further comprising, adjusting fueling via the port injectors based on the intermittent injection via the direct injectors.

10. The method of claim 9 , wherein adjusting fueling via the port injectors includes adjusting a split ratio of fuel delivered to each engine cylinder via the port injectors relative to the direct injectors.

11. The method of claim 5 , wherein each of the engine direct injectors and the high pressure fuel pump is maintained disabled until the modeled temperature is higher than an upper threshold, and wherein the temporarily reactivating is performed until the modeled temperature is below a lower threshold.

12. The method of claim 5 , wherein the modeled temperature of the pump is based on each of an engine coolant temperature and a duration of deactivation of the engine direct injectors.

13. The method of claim 5 , wherein the reactivating includes adjusting an output of the pump to provide a target fuel flow through the pump, the target fuel flow based on a difference between the modeled temperature and the threshold.

14. The method of claim 13 , wherein the target fuel flow includes one or more of a target fuel flow amount and a target fuel flow rate.

15. A method, comprising:
during warm engine idling where the engine is fueled via port injectors only,
selectively reactivating each of engine direct injectors and a high pressure fuel pump delivering fuel to the direct injectors for a duration responsive to a modeled temperature of the pump being higher than an upper threshold, the duration adjusted to reduce the modeled temperature below a lower threshold.

16. The method of claim 15 , wherein the lower threshold is a function of the upper threshold, and wherein the engine warm idling includes engine operation at lower than a threshold speed.

17. The method of claim 15 , further comprising:
while the engine is fueled via port injectors only, modeling the temperature of the pump as a function of each of measured engine coolant temperature and an amount of time elapsed since a last deactivation of the engine direct injectors.

18. The method of claim 15 , wherein selectively reactivating for a duration includes temporarily reactivating each of the engine direct injectors and the high pressure fuel pump until the modeled temperature is below the lower threshold, and then deactivating each of the engine direct injectors and the high pressure fuel pump.

19. The method of claim 18 , wherein the selectively reactivating for the duration includes:
estimating a target fuel flow through the pump based on a difference between the modeled temperature and the lower threshold; and
adjusting each of a duty cycle commanded to the pump and the duration of selective reactivation based on the target fuel flow.

20. The method of claim 15 , further comprising, for the duration when each of the engine direct injectors and the high pressure fuel pump are selectively reactivated, adjusting a duty cycle commanded to the port injectors, the duty cycle commanded to the port injectors reduced as the duration of selective reactivation of the direct injectors increases.

Assignees

• Ford Global Tech Llc

Inventors

• Sanborn Ethan D
• Thomas Joseph Lyle
• Pierce Michael Anthony

Classifications

• F02D2041/1433

  using a model or simulation of the system · CPC title

• F02D41/40 Primary

  with means for controlling injection timing or duration · CPC title

• F02D2200/021

  Engine temperature · CPC title

• F02D41/126

  transitional corrections at the end of the cut-off period · CPC title

• F02D2200/0602

  Fuel pressure · CPC title