Auxiliary combustion chamber type internal combustion engine

Abstract

An internal combustion engine includes a main combustion chamber, an auxiliary combustion chamber, a partition wall that separates the main and auxiliary combustion chambers, a first igniter disposed in the auxiliary combustion chamber, a second igniter disposed in the main combustion chamber, and a controller electrically coupled to the first and second igniters. The auxiliary combustion chamber has a capacity smaller than that of the main combustion chamber. The partition wall includes a communication passage. The controller is adapted to send an auxiliary combustion chamber ignition timing signal to the first igniter and is adapted to send a main combustion chamber ignition timing signal to the second igniter. Further, the controller is adapted to send the auxiliary and main combustion chamber ignition timing signals such that, in response to at least one engine operating condition, ignition in the auxiliary combustion chamber occurs after ignition in the main combustion chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain features of the invention.

FIG. 1 is a schematic diagram illustrating a first embodiment of an auxiliary combustion chamber type internal combustion engine.

FIGS. 2(1) and 2(2) are graphs showing relationships between phase difference, i.e., timing between ignition in a main combustion chamber and ignition in an auxiliary combustion chamber, and pressures in the main and auxiliary combustion chambers, wherein FIG. 2(1) shows the relationships when the phase difference is relatively small, and FIG. 2(2) shows the relationships when the phase difference is relatively large.

FIG. 3 is a schematic diagram illustrating combustion in a main combustion chamber and a torch flame directed from an auxiliary combustion chamber to the main combustion chamber.

FIG. 4 is a graph showing a relationship between the phase difference and torch intensity according to the first embodiment.

FIG. 5 is a graph showing relationships for given engine operating conditions between an air/fuel ratio and the phase difference according to the first embodiment.

FIG. 6 is an underside view of the main and auxiliary combustion chambers according to the first embodiment.

FIG. 7 is a graph showing a relationship between engine operating conditions and an amount of fuel supplied to the auxiliary combustion chamber according to the first embodiment.

FIG. 8 is a graph showing relationships between engine load, the amount of fuel supplied to the auxiliary combustion chamber, and the phase difference.

FIG. 9 is a schematic diagram illustrating a second embodiment of an auxiliary combustion chamber type internal combustion engine.

FIG. 10 is a schematic diagram illustrating a third embodiment of an auxiliary combustion chamber type internal combustion engine.

Claims

1. An internal combustion engine comprising: a main combustion chamber;an auxiliary combustion chamber having a capacity smaller than that of the main combustion chamber and being fluidly communicated with the main combustion chamber through a torch flame passage formed therebetween;a first igniter disposed in the auxiliary combustion chamber;a second igniter disposed in the main combustion chamber; anda controller electrically coupled to the first and second igniters and configured to determine and control ignition timings of the first and second igniters respectively in response to at least one engine operating condition such that ignition in the auxiliary combustion chamber occurs after ignition in the main combustion chamber.

2. The internal combustion engine according to claim 1, wherein the controller controls a phase difference between the ignition in the main combustion chamber and the ignition in the auxiliary combustion chamber.

3. The internal combustion engine according to claim 2, wherein the phase difference is controlled to be smaller as an engine load decreases.

4. The internal combustion engine according to claim 2, wherein the phase difference is controlled to be smaller as an engine rotation speed decreases.

5. The internal combustion engine according to claim 2, wherein the phase difference is controlled to be maximized when the engine is in a high engine load and a high engine rotation speed condition and the phase difference is controlled to be smaller as an engine load decreases.

6. The internal combustion engine according to claim 2, wherein the phase difference is controlled to substantially zero and the ignition timings of the main and auxiliary combustion chambers are retarded when the engine is in a cold start condition.

7. The internal combustion engine according to claim 1, wherein the controller discontinues the ignition in the main combustion chamber and continues the ignition in the auxiliary combustion chamber when the engine is in a predetermined low engine load level condition.

8. The internal combustion engine according to claim 1, wherein the auxiliary combustion chamber is disposed at a substantially central upper portion of the main combustion chamber, and the second igniter is disposed at an outer peripheral portion of the main combustion chamber.

9. The internal combustion engine according to claim 1, wherein the auxiliary combustion chamber is disposed at an outer peripheral portion of the main combustion chamber, and the second igniter is disposed at a central upper portion of the main combustion chamber.

10. The internal combustion engine according to claim 1, wherein the auxiliary combustion chamber is disposed at a first outer peripheral portion of the main combustion chamber, and the second igniter is disposed at a second outer peripheral portion of the main combustion chamber, and the second outer peripheral portion is disposed substantially opposite to the first outer peripheral portion.

11. The internal combustion engine according to claim 10, wherein the first outer peripheral portion is proximate to an intake port of the engine.

12. The internal combustion engine according to claim 11, further comprising: a third igniter being disposed at a substantially central upper portion of the main combustion chamber and being electrically coupled to the controller;wherein ignition in the main combustion chamber is performed by the third igniter when the engine is in a high engine load and high engine rotation speed condition above predetermined levels

13. The internal combustion engine according to claim 1, wherein the torch flame passage includes first and second torch flame passages, the first torch flame passage being oriented toward the second igniter and having a smaller opening area than that of the second torch flame passage.

14. The internal combustion engine according to claim 1, further comprising: an injector to inject fuel in the auxiliary combustion chamber.

15. The internal combustion engine according to claim 14, wherein the fuel supplied to the injector has a property of a higher combustion speed than fuel adapted to be supplied to the main combustion chamber.

16. The internal combustion engine according to claim 14, wherein a part of fuel supplied in the auxiliary combustion chamber is increased as an engine load decreases.

17. The internal combustion engine according to claim 14, wherein a part of fuel supplied in the auxiliary combustion chamber is increased as an engine rotation speed decreases.

18. An internal combustion engine comprising: a main combustion chamber;an auxiliary combustion chamber having a capacity smaller than that of the main combustion chamber and being separated from the main combustion chamber by a partition wall, the partition wall including at least one communication passage; andmeans for timing ignition in the auxiliary combustion chamber after ignition in the main combustion chamber.

19. The internal combustion engine according to claim 18, wherein the means for timing controls a phase difference between the ignition in the main combustion chamber and the ignition in the auxiliary combustion chamber, the phase difference being maximized in response to engine load and engine rotation speed increasing above predetermined levels.

20. The internal combustion engine according to claim 18, wherein the means for timing controls a phase difference between the ignition in the main combustion chamber and the ignition in the auxiliary combustion chamber and, in response to an engine cold start, the phase difference being reduced to substantially zero and the ignitions in the main and auxiliary combustion chambers being retarded.