Load transient control methods for direct-injection engines with controlled auto-ignition combustion

• US 7,370,633 B2
• Filed: 03/02/2006
• Issued: 05/13/2008
• Est. Priority Date: 03/03/2005
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Brown, Barry L., Kang, Jun-Mo, Najt, Paul M., Kuo, Tang-Wei, Chang, Chen-Fang, Sun, Zongxuan, Chang, Man-Feng, Eng, James A.
• Primary Examiner(s): HUYNH, HAI H
• Application Number:
  US11/366,217
• Publication Number:
  US 20060196467A1
• Time in Patent Office: 803 Days
• Field of Search: 123/299, 123/305, 123/90.15, 123/568.11, 123/568.14, 123/443, 123/436, 123/295, 123/492
• US Class Current: 123/305
• CPC Class Codes: F02B 1/12 with compression ignition with fuel-air charge ignited by compression ignition of an additional fuel F02B7/00
• CPC Class Codes: F02B 2075/125 Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
• CPC Class Codes: F02B 2275/14 Direct injection into combustion chamber
• CPC Class Codes: F02B 23/101 the injector being placed on or close to the cylinder centre axis, e.g. with mixture formation using spray guided concepts
• CPC Class Codes: F02B 47/08 the substances including exhaust gas
• CPC Class Codes: F02D 13/0215 changing the valve timing only
• CPC Class Codes: F02D 13/0219 by shifting the phase, i.e. the opening periods of the valves are constant
• CPC Class Codes: F02D 13/0265 Negative valve overlap for temporarily storing residual gas in the cylinder
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2041/141 using a feed-forward control element
• CPC Class Codes: F02D 2200/0614 Actual fuel mass or fuel injection amount
• CPC Class Codes: F02D 41/0052 Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
• CPC Class Codes: F02D 41/006 using internal EGR control of valve overlap for internal EGR F02D13/0261; arrangements for internal EGR F02M26/01
• CPC Class Codes: F02D 41/0065 Specific aspects of external EGR control constructional details of EGR system F02M26/00
• CPC Class Codes: F02D 41/107 and deceleration
• CPC Class Codes: F02D 41/126 transitional corrections at the end of the cut-off period
• CPC Class Codes: F02D 41/3035 a mode being the premixed charge compression-ignition mode
• CPC Class Codes: F02D 41/3064 with special control during transition between modes
• CPC Class Codes: F02D 41/402 Multiple injections
• CPC Class Codes: F02D 9/02 concerning induction conduits throttle valves, or arrangements thereof in conduits F02D9/08
• CPC Class Codes: F02M 26/01 : Internal exhaust gas recirculation, i.e. wherein the residual exhaust gases are trapped in the cylinder or pushed back from the intake or the exhaust manifold into the combustion chamber without the use of additional passages
• CPC Class Codes: F02M 26/13 : Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems

Abstract

A direct injection controlled auto-ignition engine is operated at steady state, within a homogeneous charge compression-ignition (HCCI) load range and with fuel-air-diluent mixtures at predetermined conditions, for each speed and load, of engine control inputs, including at least fueling mass flow rate, injection timing (FI), spark timing (SI) and exhaust recompression obtained by negative valve overlap (NVO). During load change rates below a predetermined threshold, SI, FI and NVO change rates are synchronized to current changes in the fueling mass flow rate. For fast load increases above the threshold, the cylinder charge is temporarily enriched by increasing the percentage of residual gas or reducing the percentage of fresh air mass in the charge sufficiently to maintain auto-ignition temperature during the load change. This may be done by delaying NVO action for a predetermined speed-dependent number of engine cycles. At very low loads, stable fuel rate reduction may require an alternate method involving deceleration fuel cut-off followed by a step change during refire.

Claims

1. Method for control of a direct-injection controlled auto-ignition lean burn engine during load transient operations, the method comprising:

operating the engine at steady state, within a homogeneous charge compression-ignition (HCCI) load range, with fuel-air-diluent mixtures at predetermined conditions, for each speed and load, of fueling mass flow rate, injection timing (FI), spark timing (SI) and exhaust recompression obtained by negative valve overlap (NVO) between closing of the exhaust valves and opening of the intake valves in each cylinder; and

at least one of

a) controlling the engine during rapid load increase from steady state at lower load to a desired steady state at higher load by synchronizing inputs to the engine, including at least two of FI, SI and NVO, to the current fueling mass flow rate, and

b) controlling the engine during rapid load decrease from steady state at higher load to a desired steady state at lower load by synchronizing inputs to the engine, including at least two of FI, SI and NVO, to the current fueling mass flow rate.

2. Method as in claim 1 wherein FI, SI, and NVO are all synchronized to the current fueling mass flow rate during at least one of rapid load increase and rapid load decrease.

3. Method as in claim 1 wherein FI, SI, and NVO are all synchronized to the current fueling mass flow rate during rapid load increase.

4. Method as in claim 1 wherein FI, SI, and NVO are all synchronized to the current fueling mass flow rate during rapid load decrease.

5. Method as in claim 1, wherein fast fueling rate changes exceeding a predetermined threshold value are called for, further comprising:

controlling the engine during a fast load increase to enrich the cylinder air-fuel mixture by providing, during the fast load increase, at least one of

1) a higher percentage of residual gas, and

2) a lower percentage of fresh air mass,

in each cylinder charge, than is required for robust steady state operation of the engine after completion of the fast load change, to provide temperature in the cylinders adequate to auto-ignite the mixture during the increase in fueling mass flow rate, resulting in increased cylinder mixture temperature during the following engine cycles.

6. Method as in claim 5 wherein said higher percentage of residual gas is provided by delaying the called for change in NVO by a speed-dependent number of engine cycles.

7. Method as in claim 1 wherein steady state HCCI engine operations are conducted using variable valve actuation including two-step valve actuation with dual cam phasing.

8. Method for control of a direct-injection controlled auto-ignition engine under stoichiometric operation during load transient operations, the method comprising:

operating the engine at steady state, within a homogeneous charge compression-ignition (HCCI) load range, with fuel-air-diluent mixtures at predetermined conditions, for each speed and load, of fueling mass flow rate, injection timing (FI), spark timing (SI), throttle position, exhaust gas recirculation (EGR) valve setting, and exhaust recompression obtained by negative valve overlap (NVO) between closing of the exhaust valves and opening of the intake valves in each cylinder; and

at least one of

a) controlling the engine during rapid load increase from a steady state at lower load to a desired steady state at higher load by synchronizing controlled inputs to the engine, including at least three of FI, SI, throttle position, EGR valve setting and NVO, to the current fueling mass flow rate, and

b) controlling the engine during rapid load decrease from a steady state at higher load to a desired steady state at lower load by synchronizing inputs to the engine, including at least three of FI, SI, throttle position, EGR valve selling and NVO, to the current fueling mass flow rate.

9. Method as in claim 8 wherein FI, SI, throttle position, EGR valve setting and NVO are all synchronized to the current fueling mass flow rate during at least one of rapid load increase and rapid load decrease.

10. Method as in claim 8 wherein FI, SI, throttle position, EGR valve setting and NVO are all synchronized to the current fueling mass flow rate during rapid load increase.

11. Method as in claim 8 wherein FI, SI, throttle position, EGR valve setting and NVO are all synchronized to the current fueling mass flow rate during rapid load decrease.

12. Method as in claim 8, wherein fast fueling rate changes exceeding a predetermined threshold value are called for, further comprising:

controlling the engine during a fast load increase to enrich the cylinder air-fuel mixture by providing, during the fast load increase, at least one of

1) a higher percentage of residual gas, and

2) a lower percentage of fresh air mass,

in each cylinder charge, than is required for robust steady state operation of the engine after completion of the fast load increase, to provide temperature in the cylinders adequate to auto-ignite the mixture during the increase in fueling mass flow rate, resulting in increased cylinder mixture temperature during the following engine cycles.

13. Method as in claim 12 wherein said higher percentage of residual gas is provided by delaying the called for change in at least one of NVO, throttle position and EGR valve setting by a speed-dependent number of engine cycles.

14. Method as in claim 8 wherein steady state HCCI engine operations are conducted using variable valve actuation including two-step valve actuation with dual cam phasing.

15. Method for control of a direct-injection controlled auto-ignition engine during load transient operations, the method comprising:

operating the engine at steady state, within a homogeneous charge compression-ignition (HCCI) load range, with fuel-air-diluent mixtures at predetermined conditions, for each speed and load, of fueling mass flow rate, injection timing (FI), spark timing (SI), throttle position, exhaust gas recirculation (EGR) valve setting, and exhaust recompression obtained by negative valve overlap (NVO) between closing of the exhaust valves and opening of the intake valves in each cylinder; and

at least one of

a) controlling the engine during rapid load increase from a steady state at lower load to a desired steady state at higher load by synchronizing controlled inputs to the engine, including at least three of FI, SI, throttle position, EGR valve setting and NVO, to the current fueling mass flow rate, and

b) controlling the engine during rapid load decrease from a steady state at higher load to a desired steady state at lower load by synchronizing inputs to the engine, including at least three of FI, SI, throttle position, EGR valve selling and NVO, to the current fueling mass flow rate.

16. Method as in claim 15 wherein the engine is operated with lean air-fuel ratios and FI, SI, and NVO are all synchronized to the current fueling mass flow rate during at least one of rapid load increase and rapid load decrease.

17. Method as in claim 16, wherein fast fueling rate changes exceeding a predetermined threshold value are called for, further comprising:

controlling the engine during a fast load increase to enrich the cylinder air-fuel mixture by providing, during the fast load increase, at least one of

1) a higher percentage of residual gas, and

2) a lower percentage of fresh air mass,

in each cylinder charge, than is required for robust steady state operation of the engine after completion of the fast load change, to provide residual exhaust temperature in the cylinders adequate to auto-ignite the mixture during the increase in fueling mass flow rate, resulting in increased exhaust temperature during the following engine cycles.

18. Method as in claim 15 wherein HCCI engine operations are conducted using variable valve actuation including two-step valve actuation with dual cam phasing.

19. Method as in claim 15 wherein the engine is operated with stoichiometric air-fuel ratios and at least FI and SI are synchronized to the current fueling mass flow rate during at least one of rapid load increase and rapid load decrease.

20. Method as in claim 19, wherein fast fueling rate changes exceeding a predetermined threshold value are called for, further comprising:

controlling the engine during a fast load increase to enrich the cylinder air-fuel mixture by providing, during the fast load increase, at least one of

1) a higher percentage of residual gas, and

2) a lower percentage of fresh air mass,

in each cylinder charge, than is required for robust steady state operation of the engine after completion of the fast load increase, to provide temperature in the cylinders adequate to auto-ignite the mixture during the increase in fueling mass flow rate, resulting in increased cylinder mixture temperature during the following engine cycles.