CONTROL SYSTEM AND CONTROL METHOD FOR VEHICLE

• US 20100212315A1
• Filed: 09/25/2008
• Published: 08/26/2010
• Est. Priority Date: 09/27/2007
• Status: Abandoned Application

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Irisawa, Yasuyuki
• Application Number:
  US12/600,404
• Publication Number:
  US 20100212315A1
• Time in Patent Office: Days
• US Class Current: 60/602
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60W 2510/068 Engine exhaust temperature
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: F01N 13/107 More than one exhaust manifold or exhaust collector
• CPC Class Codes: F02B 37/02 Gas passages between engine outlet and pump drive, e.g. reservoirs
• CPC Class Codes: F02D 13/0246 changing valve lift or valve lift and timing
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/1446 the characteristics being exhaust temperatures
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A catalyst warm-up control is carried out in a state with a first exhaust valve closed and a second exhaust valve opened. After completion of the catalyst warm-up, if there is an acceleration request, exhaust gas temperature is acquired. If the exhaust gas temperature is equal to or lower than a predetermined value, the second exhaust valve is opened to an intermediate lift to thereby prevent an abrupt drop in exhaust gas temperature. If the exhaust gas temperature is higher than the predetermined value, the second exhaust valve is fully closed to thereby introduce the whole amount of exhaust gas to a turbine. A vehicle control device that achieves both prevention of catalyst deactivation and acceleration performance enhancement can be thus provided.

Claims

1. A control system for a vehicle having an internal combustion engine with a turbocharger, comprising:

a first exhaust valve that opens and closes a first exhaust passage leading to a turbine of the turbocharger;

a second exhaust valve that opens and closes a second exhaust passage leading to downstream of the turbine;

a variable valve mechanism that makes a lift of the second exhaust valve variable;

a catalyst arranged downstream of a junction of the first exhaust passage and the second exhaust passage; and

a control portion that controls opening and closing of the first and second exhaust valves, wherein

when switching from a first state in which the first exhaust valve is closed and the second exhaust valve is opened, to a second state in which the first exhaust valve is opened and the second exhaust valve is closed, the control interposes a third state in which the first exhaust valve is opened and the second exhaust valve is opened to an intermediate lift within a predetermined range, between the first state and the second state, by using the variable valve mechanism.

2. The control system according to claim 1, further comprising

an exhaust gas temperature acquiring portion that acquires temperature of exhaust gas that flows into the catalyst, wherein

the control portion controls the first and second exhaust valves to the third state when an exhaust gas temperature acquired by the exhaust gas temperature acquiring portion is equal to or lower than a predetermined value.

3. The control system according to claim 2, wherein when the exhaust gas temperature is equal to or lower than a predetermined value, the control portion sets the intermediate lift of the second exhaust valve smaller as the exhaust gas temperature becomes higher.

4. The control system according to claim 1, further comprising:

an electric motor as a drive source other than the internal combustion engine; and

an operating point control portion that controls an operating point of the internal combustion engine on an iso-output curve along which a total output of the internal combustion engine and the electric motor is constant, wherein

the operating point control portion controls the operating point to a higher rotation side when the first and second exhaust valves are controlled to the third state by the control portion, than when the first and second exhaust valves are controlled to the second state.

5. The control system according to claim 4, wherein when the first and second exhaust valves are controlled to the third state by the control portion, the operating point control portion controls the operating point to a higher rotation side as the intermediate lift of the second exhaust valve becomes larger.

6. A control method for a vehicle having an internal combustion engine with a turbocharger, comprising:

closing a first exhaust valve that opens and closes a first exhaust passage leading to a turbine of the turbocharger, and opening a second exhaust valve that opens and closes a second exhaust passage leading to downstream of the turbine;

opening the first exhaust valve, and opening the second exhaust valve to an intermediate lift within a predetermined range by using a variable valve mechanism that makes a lift of the second exhaust valve variable; and

opening the first exhaust valve and closing the second exhaust valve, wherein

a catalyst is arranged downstream of a junction of the first exhaust passage and the second exhaust passage.