Internal combustion engine and method of operating same

• US 6,711,894 B2
• Filed: 05/02/2002
• Issued: 03/30/2004
• Est. Priority Date: 05/02/2001
• Status: Expired due to Fees

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Inventors: Bruenemann, Ralf, Holder, Eberhard, Kemmler, Roland, Koehlen, Christoph, Matt, Martin
• Primary Examiner(s): TRAN, BINH Q
• Application Number:
  US10/136,432
• Publication Number:
  US 20020178713A1
• Time in Patent Office: 698 Days
• Field of Search: 602/74, 602/83, 602/84, 602/89, 602/90, 602/91, 602/93, 602/85, 123/516, 123/518, 123/519, 123/521, 123/520
• US Class Current: 60/289
• CPC Class Codes: F01N 3/22 Control of additional air supply only, e.g. using by-passes or variable air pump drives
• CPC Class Codes: F01N 3/30 Arrangements for supply of additional air control, e.g. using by-passes or variable air pump drives, F01N3/22
• CPC Class Codes: F02D 41/025 by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An internal combustion engine has a preparation device for fuel, for the purpose of providing a starting fuel which comprises low-boiling fuel constituents. A catalytic converter is accommodated in an exhaust train of the internal combustion engine. After-treatment of the exhaust gases is carried out by a secondary air device, by means of the combustion being carried out with an excess of starting fuel for rich-burn operation during the cold start and the subsequent warm-up phase. The system is provided for spark-ignition mixture-compressing or spark-ignition direct injection internal combustion engines.

Claims

1. Internal combustion engine having any one of a distillation device, a reformer device and an evaporator configured to provide a starting fuel in a nonvaporous condition which comprises low-boiling fuel constituents, and having a catalytic converter in an exhaust train of the internal combustion engine, wherein a secondary air device is provided for after-treatment of the exhaust gases, wherein with the secondary air device secondary air is blown into the exhaust train upstream of the catalytic converter, wherein the combustion being carried out with the use of an excess of starting fuel (rich-burn operation) during the cold start and the subsequent warm-up phase, whereby a partial oxidation occurs with increased emissions of carbon monoxide (CO) and hydrogen (H₂) for improving the afterburning or post-oxidation.

2. Internal combustion engine according to claim 1, wherein an ignition angle in cold-start mode and during the subsequent warm-up phase of the internal combustion engine is shifted in a direction of late.

3. Internal combustion engine according to claim 1, wherein, while power is being demanded from the internal combustion engine (acceleration), the blowing of secondary air is switched off and operation of the internal combustion engine continues with starting fuel and under stoichiometric combustion.

4. Internal combustion engine according to claim 1, wherein after the internal combustion engine has been started, operation takes place by means of starting fuel for approximately 50 to 90 seconds, and then the internal combustion engine is operated by means of standard fuel.

5. Internal combustion engine according to claim 1, wherein after the internal combustion engine has been started, operation takes place by means of starting fuel for approximately 70 to 80 seconds, and then the internal combustion engine is operated by means of standard fuel.

6. Internal combustion engine according to claim 1, wherein after the internal combustion engine has been started, operation takes place by means of starting fuel for approximately about 75 seconds, and then the internal combustion engine is operated by means of standard fuel.

7. Method for operating an internal combustion engine having any one of a distillation device, a reformer device or an evaporator providing a starting fuel in nonvaporous condition, which comprises low-boiling fuel constituents, and having a catalytic converter in an exhaust train of the internal combustion engine, said method comprising

operating a secondary air device for after-treatment of the exhaust gases,

blowing secondary air with the secondary air device into the exhaust train upstream of the catalytic converter and

carrying out the combustion with the use of an excess of starting fuel (rich-burn operation) during the cold start and the subsequent warm-up phase improving the afterburning or post-oxidation to perform a partial oxidation with increased emissions of carbon monoxide (CO) and hydrogen (H₂).

8. Method according to claim 7, wherein an ignition angle in cold-start mode and during the subsequent warm-up phase of the internal combustion engine is shifted in a direction of late.

9. Method according to claim 7, wherein when power is being demanded from the internal combustion engine (acceleration), the blowing of secondary air is switched off and operation of the internal combustion engine continues with starting fuel and under stoichiometric combustion.

10. Method according to claim 7, wherein after the internal combustion engine has been started, operation takes place by means of starting fuel for approximately 50 to 90 seconds, and then the internal combustion engine is operated by means of standard fuel.

11. Method according to claim 7, wherein after the internal combustion engine has been started, operation takes place by means of starting fuel for approximately 70 to 80 seconds, and then the internal combustion engine is operated by means of standard fuel.

12. Method according to claim 7, wherein after the internal combustion engine has been started, operation takes place by means of starting fuel for approximately about 75 seconds, and then the internal combustion engine is operated by means of standard fuel.

13. An internal combustion engine comprising:

means for supplying a starting fuel in nonvaporous condition on demand which comprises low-boiling constituents to an intake line leading to an engine combustion space,

a catalytic converter disposed in an engine exhaust train downstream of the combustion space,

a secondary air device operable to blow secondary air into the exhaust train upstream of the catalytic converter, and

control means operable to operate the engine with combustion being carried out with the use of an excess of said starting fuel during a cold engine start and during a subsequent warm-up of phase of said engine and being carried out with a partial oxidation with increased emissions of carbon monoxide (CO) and hydrogen (H₂) for improving the afterburning or post-oxidation.

14. An internal combustion engine according to claim 13, wherein said control means is operable during engine power demands, immediately following a cold start to switch off blowing of secondary air in the exhaust train while maintaining engine operation with starting fuel and under stoichiometric combustion.

15. An internal combustion engine according to claim 13, wherein said control means is operable to supply starting fuel after a cold engine start for a period of 50-90 seconds, followed by operation with standard fuel.

16. An internal combustion engine according to claim 13, wherein said control means is operable to supply starting fuel after a cold engine start for a period of 70-80 seconds, followed by operation with standard fuel.

17. An internal combustion engine according to claim 13, wherein said control means is operable to supply starting fuel after a cold engine start for a period of 75 seconds, followed by operation with standard fuel.

18. A method for operating an internal combustion engine which includes:

means for supplying a starting fuel in nonvaporous condition on demand which comprises low-boiling constituents to an intake line leading to an engine combustion space,

a catalytic converter disposed in an engine exhaust train downstream of the combustion space,

a secondary air device operable to blow secondary air into the exhaust train upstream of the catalytic converter, and

control means operable to operate the engine with combustion being carried out with the use of an excess of said starting fuel during a cold engine start and during a subsequent warm-up of phase of said engine, and

said method comprising carrying out combustion with an excess of said starting fuel during a cold engine start and during a subsequent warm-up of phase of said engine, so that a partial oxidation with increased emissions of carbon monoxide (CO) and hydrogen (H₂) takes place for improving the afterburning or post-oxidation.

19. A method according to claim 18, comprising operating the engine during engine power demands immediately following a cold start by switching off blowing of secondary air in the exhaust train while maintaining engine operation with starting fuel and under stoichiometric combustion.

20. A method according to claim 18, comprising supplying starting fuel after a cold engine start for a period of 50-90 seconds, followed by operation with standard fuel.

21. A method according to claim 18, comprising supplying starting fuel after a cold engine start for a period of 70-80 seconds, followed by operation with standard fuel.

22. A method according to claim 18, comprising supplying starting fuel after a cold engine start for a period of about 75 seconds, followed by operation with standard fuel.