Compression ignition type engine

• US 20020038654A1
• Filed: 09/28/2001
• Published: 04/04/2002
• Est. Priority Date: 10/04/2000
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Murata, Hiroki, Sasaki, Shizuo, Igarashi, Kohei
• Granted Patent: US 6,581,372 B2
• Time in Patent Office: Days
• US Class Current: 123/568.11
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/54 Transmission for changing ratio
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2710/0622 Air-fuel ratio
• CPC Class Codes: B60Y 2300/476 Regeneration of particle filters
• CPC Class Codes: B60Y 2400/435 Supercharger or turbochargers
• CPC Class Codes: F01N 2570/16 Oxygen
• CPC Class Codes: F01N 3/0233 periodically cleaning filter by blowing a gas through the filter in a direction opposite to exhaust flow, e.g. exposing filter to engine air intake
• CPC Class Codes: F01N 3/035 with catalytic reactors , e.g. catalysed diesel particulate filters
• CPC Class Codes: F01N 3/0821 combined with particulate filters catalysed diesel particulate filters F01N3/035
• CPC Class Codes: F01N 3/0842 Nitrogen oxides
• CPC Class Codes: F02B 23/06 the combustion space being arranged in working piston F02B23/04 takes precedence
• CPC Class Codes: F02B 23/0672 Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis the surrounding wall being exactly vertical F02B23/0696
• CPC Class Codes: F02B 29/0406 Layout of the intake air cooling or coolant circuit
• 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 37/00 : Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: F02D 2250/24 : by using an external load, e.g. a generator
• CPC Class Codes: F02D 41/0275 : the exhaust gas treating apparatus being a NOx trap or adsorbent
• CPC Class Codes: F02D 41/3035 : a mode being the premixed charge compression-ignition mode
• CPC Class Codes: F02M 26/06 : Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor
• CPC Class Codes: F02M 26/15 : in relation to engine exhaust purifying apparatus
• CPC Class Codes: F02M 26/23 : Layout, e.g. schematics
• CPC Class Codes: F02M 26/33 : controlling the temperature of the recirculated gases
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/917 : with transmission for changing gear ratio

Abstract

A compression ignition type engine selectively switching between a first combustion where an amount of recirculated exhaust gas supplied in a combustion chamber (5) is greater than an amount of recirculated exhaust gas where the amount of production of soot peaks and a second combustion where the amount of recirculated exhaust gas supplied in the combustion chamber (5) is smaller than the amount of recirculated exhaust gas where the amount of production of soot peaks. A particulate filter (24) carrying a NO_x absorbent (71) is arranged in the engine exhaust passage. When SOx should be released from the NOx absorbent (71) and there is leeway in the electrical energy stored in the battery (41), the first combustion is performed even when the second combustion should be performed and the drop in output power of the energy is made up by the output torque of an electric motor (37).

Claims

1. A compression ignition type engine in which an amount of production of soot gradually increases and then peaks when an amount of inert gas in a combustion chamber increases and in which a further increase of the amount of inert gas in the combustion chamber results in a temperature of fuel and surrounding gas in the combustion chamber becoming lower than a temperature of production of soot and therefore almost no production of soot any longer, said engine comprising:

an exhaust passage;

an NO_x absorbent arranged in said exhaust passage, said NO_x absorbent absorbing NO_x when an air-fuel ratio of inflowing exhaust gas is lean and releasing the absorbed NO_x when the air-fuel ratio of the inflowing exhaust gas is rich or the stoichiometric air-fuel ratio;

switching means for selectively switching between a first combustion where the amount of the inert gas in the combustion chamber is larger than the amount of inert gas where the amount of production of soot peaks and a second combustion where the amount of inert gas in the combustion chamber is smaller than the amount of inert gas where the amount of production of soot peaks;

an electric motor for generating a vehicle drive power separate from a drive power of the engine;

a battery for driving the electric motor;

decision means for deciding if an amount of electrical energy stored in said battery is more than a predetermined amount; and

control means for performing the first combustion, making the air-fuel ratio in the combustion chamber rich or the stoichiometric air-fuel ratio, and generating drive power at the electric motor even when the second combustion should be performed when NO_x or SO_x should be released from the NO_x absorbent and the amount of electrical energy stored in the battery is more than the predetermined amount.

2. An internal combustion engine as set forth in claim 1, wherein said control means performs second combustion when the second combustion should be performed and said control means also controls fuel injection so that a temperature of the NO_x absorbent rises if the amount of electrical energy stored in the battery is less than the predetermined amount, when NO_x or SO_x should be released from the NO_x absorbent.

3. An internal combustion engine as set forth in claim 1, wherein said control means maintains an output torque of the engine at substantially a maximum output torque where the first combustion can be performed and a drop of the engine output torque is made up for by the output torque of the electric motor when performing the first combustion when the second combustion should be performed.

4. An internal combustion engine as set forth in claim 1, wherein said control means makes the air-fuel ratio in the combustion chamber rich or the stoichiometric air-fuel ratio when the first combustion is performed when NO_x or SO_x should be released from the NO_x absorbent.

5. An internal combustion engine as set forth in claim 1, wherein said control means reduces the output torque of the engine, makes the air-fuel ratio in the combustion chamber rich or the stoichiometric air-fuel ratio, and makes the electric motor generate drive power so as to make up for the drop in the engine output torque by the output torque of the electric motor when NO_x or SO_x should be released from the NO_x absorbent, the first combustion is being performed, and the amount of electrical energy stored in the battery is more than the predetermined amount.

6. An internal combustion engine as set forth in claim 1, wherein detecting means is provided for detecting the temperature of the NO_x absorbent and said control means reduces the output torque of the engine, makes the air-fuel ratio in the combustion chamber rich or the stoichiometric air-fuel ratio, makes the electric motor generate drive power so as to make up for the drop in the engine output torque by the output torque of the electric motor, and controls the ratio of the engine output torque and the output torque of the electric motor so that the temperature of the NO_x absorbent falls within a predetermined temperature range when NO_x or SO_x should be released from the NO_x absorbent and the amount of electrical energy stored in the battery is more than the predetermined amount.

7. An internal combustion engine as set forth in claim 1, wherein an operating region of the engine is divided into a first operating region on a low load side and a second operating region on a high load side, the first combustion is performed in the first operating region, and the second combustion is performed in the second operating region.

8. An internal combustion engine as set forth in claim 1, wherein an exhaust gas recirculation device is provided for recirculating exhaust gas exhausted from the combustion chamber into an intake passage of the engine, the inert gas comprises recirculated exhaust gas, the exhaust gas recirculation rate is made more than about 55 percent when the first combustion is being performed, and the exhaust gas recirculation rate is made less than about 50 percent when the second combustion is being performed.

9. An internal combustion engine as set forth in claim 1, wherein a particulate filter arranged in said exhaust passage is provided, and as said particulate filter, use is made of a particulate filter able to remove by oxidation any particulate in an exhaust gas flowing into the particulate filter without emitting a luminous flame when an amount of discharged particulate discharged from the combustion chamber per unit time is smaller than an amount of particulate which can be removed by oxidation without emitting a luminous flame per unit time on the particulate filter;

and said particulate filter simultaneously has the function of an NO_x absorbent.

10. An internal combustion engine as set forth in claim 9, wherein a precious metal catalyst is carried on the particulate filter.

11. An internal combustion engine as set forth in claim 10, wherein an active oxygen release agent, which takes in the oxygen and holds the oxygen when excess oxygen exists in surroundings, and releases the held oxygen in the form of active oxygen when the concentration of oxygen in the surroundings falls, is carried on the particulate, and active oxygen is released from the active oxygen release agent when particulate deposits on the particulate filter, and particulate deposited on the particulate filter is oxidized by the released active oxygen.