Spark-assist type self-ignition engine

• US 6,293,246 B1
• Filed: 01/28/1999
• Issued: 09/25/2001
• Est. Priority Date: 01/30/1998
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Yasuda, Yushiro, Tanahashi, Toshio, Asada, Toshiaki, Murai, Toshimi
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US09/239,400
• Time in Patent Office: 971 Days
• Field of Search: 123/406.41, 123/406.42, 123/406.55, 123/568.21, 123/295, 123/305, 123/435, 602/78, 602/79
• US Class Current: 123/305
• CPC Class Codes: F01L 1/34 characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
• CPC Class Codes: F01N 13/011 having two or more purifying devices arranged in parallel
• CPC Class Codes: F01N 3/20 specially adapted for catalytic conversion F01N3/22 takes precedence; Methods of operation or control of catalytic converters
• CPC Class Codes: F01N 3/28 Construction of catalytic reactors
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• 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 11/00 Engines characterised by both fuel-air mixture compression and air compression, or characterised by both positive ignition and compression ignition, e.g. in different cylinders
• CPC Class Codes: F02B 17/005 having direct injection in the combustion chamber
• 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 23/10 with separate admission of air and fuel into cylinder
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 33/38 of Roots type
• CPC Class Codes: F02B 33/446 having valves for admission of atmospheric air to engine, e.g. at starting
• CPC Class Codes: F02D 13/0215 changing the valve timing only
• CPC Class Codes: F02D 13/028 for two-stroke engines
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 2200/602 Pedal position
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 35/025 : by determining temperatures inside the cylinder, e.g. combustion temperatures
• CPC Class Codes: F02D 35/027 : using knock sensors
• CPC Class Codes: F02D 37/02 : one of the functions being ignition
• CPC Class Codes: F02D 41/1454 : the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/1498 : measuring engine roughness
• CPC Class Codes: F02D 41/187 : using a hot wire flow sensor
• CPC Class Codes: F02D 41/3041 : with means for triggering compression ignition, e.g. spark plug
• CPC Class Codes: F02D 41/3827 : for diesel engines
• CPC Class Codes: F02F 3/26 : having combustion chamber in piston head the surface thereof being covered F02F3/14
• CPC Class Codes: F02M 26/03 : with a single mechanically or electrically driven intake charge compressor
• CPC Class Codes: F02M 26/10 : having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system
• CPC Class Codes: F02M 26/15 : in relation to engine exhaust purifying apparatus
• CPC Class Codes: F02M 26/43 : in which exhaust from only one cylinder or only a group of cylinders is directed to the intake of the engine
• CPC Class Codes: F02M 69/045 : for injecting into the combustion chamber F02M69/046 takes precedence
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

An engine comprising a spark plug and a fuel injector in a combustion chamber and a temperature sensor used to judge if the gas temperature in the combustion chamber is a temperature at which self-ignition occurs when a spark is generated. Based on this judgement, a valve timing device is used to control the opening timing of the intake valve and maintain the gas temperature at a temperature at which self-ignition occurs when a spark is generated.

Claims

1. A spark-assist type self-ignition engine comprising:

a combustion chamber;

a spark plug arranged in the combustion chamber;

judging means for judging if a gas temperature in the combustion chamber at the end of a compression stroke is a target temperature or within a target temperature range at which substantially simultaneous ignition of an entire air-fuel mixture is caused when a spark is generated; and

control means for controlling the gas temperature in the combustion chamber at the end of the compression stroke to the target temperature range based on the results of judgement of the judging means.

2. A spark-assist type self-ignition engine as set forth in claim 1, wherein the target temperature or the target temperature range is a function of the pressure.

3. A spark-assist type self-ignition engine as set forth in claim 1, wherein detecting means is provided for detecting the gas temperature in the combustion chamber and wherein said judging means judges if the gas temperature in the combustion chamber at the end of the compression stroke is the target temperature or within the target temperature range from the gas temperature detected by the detecting means.

4. A spark-assist type self-ignition engine as set forth in claim 1, wherein detecting means is provided for detecting a time until a pressure inside the combustion chamber after the generation of a spark peaks, said judging means judges if the gas temperature in the combustion chamber at the end of the compression stroke is the target temperature or within the target temperature range from said time, and the control means controls said time so that it becomes a predetermined time so as to control the gas temperature in the combustion chamber at the end of the compression stroke to the target temperature or within the target temperature range.

5. A spark-assist type self-ignition engine as set forth in claim 1, wherein a knocking sensor is provided for detecting knocking, said judging means judges if the gas temperature in the combustion chamber at the end of the compression stroke is the target temperature or within the target temperature range from an output signal of the knocking sensor, and the control means controls the strength of the knocking to a predetermined range so as to control the gas temperature in the combustion chamber at the end of the compression stroke to the target temperature or within the target temperature range.

6. A spark-assist type self-ignition engine as set forth in claim 1, wherein an exhaust gas recirculation device is provided for recirculating exhaust gas in an engine intake passage and wherein said control means controls one of the amount and temperature of the recirculated exhaust gas to control the gas temperature in the combustion chamber at the end of the compression stroke to the target temperature or within the target temperature range.

7. A spark-assist type self-ignition engine as set forth in claim 1, wherein means for controlling an opening timing of an intake valve is provided and wherein said control means controls the opening timing of the intake valve so as to control the gas temperature in the combustion chamber at the end of the compression stroke to the target temperature or within the target temperature range.

8. A spark-assist type self-ignition engine as set forth in claim 1, wherein means for controlling a compression ratio of the engine is provided and wherein said control means controls said compression ratio so as to control the gas temperature in the combustion chamber at the end of the compression stroke to the target temperature or within the target temperature range.

9. A spark-assist type self-ignition engine as set forth in claim 1, wherein means for controlling a supercharging pressure of intake air supplied to the engine is provided and wherein said control means controls said supercharging pressure so as to control the gas temperature in the combustion chamber at the end of the compression stroke to the target temperature or within the target temperature range.

10. A spark-assist type self-ignition engine as set forth in claim 1, wherein means for controlling an opening timing of an exhaust valve is provided and wherein said control means controls the opening timing of the exhaust valve so as to control the gas temperature in the combustion chamber at the end of the compression stroke to the target temperature or within the target temperature range.

11. A spark-assist type self-ignition engine as set forth in claim 1, wherein spark timing control means is provided for controlling a spark timing so that a spark is generated when the gas temperature in the combustion chamber at the end of the compression stroke is the target temperature or within the target temperature range.

12. A spark-assist type self-ignition engine as set forth in claim 1, wherein the control of the gas temperature in the combustion chamber by the control means is assisted by the provision of auxiliary control means in addition to the control means.

13. A spark-assist type self-ignition engine as set forth in claim 12, wherein the auxiliary control means is comprised of means for making an air-fuel ratio of at least one cylinder rich, a catalyst arranged in an exhaust passage of a cylinder with a rich air-fuel ratio, and means for supplying exhaust gas passing through the catalyst to at least one remaining cylinder.

14. A spark-assist type self-ignition engine as set forth in claim 12, wherein said auxiliary control means is comprised of cooling control means for controlling the cooling action of the engine.

15. A spark-assist type self-ignition engine as set forth in claim 1, wherein a plurality of spark plugs are provided.

16. A spark-assist type self-ignition engine as set forth in claim 1, wherein injecting means for injecting additional fuel after substantially simultaneous ignition of the entire air-fuel mixture by a spark is provided.

17. A spark-assist type self-ignition engine as set forth in claim 1, wherein a piston is provided, a cavity is formed in a top surface of the piston, and fuel is injected in the cavity.

18. A spark-assist type self-ignition engine as set forth in claim 1, wherein an NOx absorbent is arranged in an engine exhaust passage, said NOx absorbent absorbs NOx when an air-fuel ratio of exhaust gas flowing into it is lean, and releases the absorbed NOx when the air-fuel ratio in the combustion chamber is made the stoichiometric air-fuel ratio or rich when the NOx is to be released from the NOx absorbent, and at this time, substantially simultaneous ignition of the entire air-fuel mixture by a spark is provided.

19. A spark-assist type self-ignition engine as set forth in claim 1, wherein an air-fuel mixture is formed concentratedly around the spark plug when an engine load is lower than a predetermined load.