WASTE HEAT CONTROLLER

• US 20110197853A1
• Filed: 02/15/2011
• Published: 08/18/2011
• Est. Priority Date: 02/15/2010
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Takeishi, Hiroaki, Kawano, Takanobu, Hara, Mitsuo, Senda, Takashi
• Granted Patent: US 9,863,393 B2
• Time in Patent Office: Days
• US Class Current: 123/406.45
• CPC Class Codes: B60H 1/08 from other radiator than main radiator
• CPC Class Codes: F01N 5/02 the devices using heat
• CPC Class Codes: F01P 2060/08 Cabin heater
• CPC Class Codes: F01P 2060/16 Outlet manifold
• CPC Class Codes: F02D 13/0215 changing the valve timing only
• CPC Class Codes: F02D 13/0261 Controlling the valve overlap
• CPC Class Codes: F02D 13/0269 Controlling the valves to perform a Miller-Atkinson cycle
• CPC Class Codes: F02D 15/00 Varying compression ratio
• CPC Class Codes: F02G 5/02 Profiting from waste heat of exhaust gases
• CPC Class Codes: F02M 26/15 in relation to engine exhaust purifying apparatus
• CPC Class Codes: F02P 5/04 automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions dependent on position of personal controls of engine F02P5/02
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An ECU controls waste heat quantity of an engine according to a required heat quantity in response to a heat-utilize requirement. The ECU controls a valve opening period of an intake valve based on an engine driving condition and an ignition timing based on a most efficient timing at which fuel economy is highest. The ECU determines whether there is an ignition advance margin relative to the most efficient timing. When there is no margin, an actual compression ration of the engine is decreased by advancing or retarding a valve close timing of the intake valve and the ignition timing is advanced relative to the most efficient timing in order to increase the waste heat quantity.

Claims

1. A waste heat controller controlling a waste heat quantity of an engine based on a required heat quantity in response to a heat-utilize requirement, comprising:

an intake valve control means for controlling an opening period of an intake valve of the engine based on an engine driving condition;

an ignition control means for controlling an ignition timing of the engine based on a most efficient timing at which a highest brake thermal efficiency is obtained in a current engine driving condition;

a margin determination means for determining, based on the current engine driving condition, whether there is an ignition advance margin relative to the most efficient timing; and

a waste heat control means for executing

an actual compression ratio decreasing control in which an actual compression ration of the engine is decreased by advancing or retarding a valve close timing of the intake valve by the intake valve control means and

an ignition timing advance control in which the ignition timing is advanced relative to the most efficient timing by the ignition control means in order to increase the waste heat quantity, when the margin determination means determines that there is no ignition advance margin relative to the most efficient timing.

2. A waste heat controller according to claim 1, wherein

the actual compression ratio decreasing control is a retard control in which the valve close timing of the intake valve is retarded to decrease the actual compression ratio, further comprising

a valve overlap control means for controlling a valve overlap period during which a valve opening period of the intake valve and a valve opening period of the exhaust valve overlap with each other, wherein

based on the engine driving condition, the margin determination means determines whether there is an ignition advance margin relative to the most efficient timing at a time after the valve overlap period is varied in a case that the valve overlap period is increased by varying a valve opening period of the intake valve.

3. A waste heat controller according to claim 2, wherein

the waste heat control means executes a first waste heat increasing control in which the valve close timing of the intake valve is retarded, the ignition timing is advanced and the valve overlap period is increased by varying a valve opening period of the exhaust valve in order to increase the waste heat quantity when the margin determination means determines there is no ignition advance margin, and

the waste heat control means executes a second waste heat increasing control in which the valve overlap period is increased by varying a valve opening period of the intake valve and the ignition timing is advanced in order to increase the waste heat quantity when the margin determination means determines there is the ignition advance margin.

4. A waste heat controller according to claim 1, wherein

the waste heat control means defines a variation quantity in the valve close timing of the intake valve based on the required heat quantity and controls the opening period of the intake valve based on the variation quantity in the valve close timing of the intake valve when the margin determination means determines there is no ignition advance margin.

5. A waste heat controller according to claim 1, wherein

when the margin determination means determines that the current engine driving condition is varied from a condition where there is no ignition advance margin to another condition where there is the ignition advance margin, the valve opening timing of the exhaust valve is advanced before the valve opening timing of the intake valve is advanced.