DIESEL ENGINE WITH REDUCED PARTICULATE MATERIAL ACCUMULATION AND RELATED METHOD

摘要

The present invention provides a diesel engine capable of preventing a PM accumulation amount from increasing excessively. If DOC inlet exhaust gas temperature (“IEGT”) does not reach a predetermined value T0, a control unit carries out air intake amount feedback control (“AIAFC”), and a target value of intake throttling is set to a predetermined air intake amount. If the DPF regenerating processing is not started even if elapsed time reaches a predetermined value t after AIAFC is started in a state where the DOC IEGT does not reach the predetermined value T0, the control unit changes AIAFC to exhaust gas temperature feedback control (“EGTFC”). In EGTFC, the control unit changes a target value of intake throttling to a predetermined DOC IEGT T0. If application of a load exceeding a predetermined amount is detected before the DOC IEGT reaches the predetermined value T0, the control unit returns EGTFC to AIAFC.

主权项

1. A diesel engine comprising a DOC (1), a DPF (2), a PM accumulation amount estimating device (3) of the DPF (2), a control unit (4), a DPF regenerating device (5), a DOC inlet exhaust gas temperature detector (6), an intake throttle device (7), an air intake amount detector (8) and a load detector (9), wherein when a PM accumulation estimate value of the DPF (2) reaches a predetermined value (P) and DOC inlet exhaust gas temperature reaches a predetermined value (T0), DPF regenerating processing is started, unburned fuel is mixed into exhaust gas (10) in the DPF regenerating processing by the DPF regenerating device (5) under control of the control unit (4), temperature of exhaust gas (10) rises by catalytic combustion at the DOC (1) of the unburned fuel, PM accumulated on the DPF (2) is burned and removed and the DPF (2) is regenerated, when the DOC inlet exhaust gas temperature does not reach the predetermined value (T0), air intake amount feedback control is carried out by the control unit (4), in the air intake amount feedback control, a target value of DPF regenerating intake throttling is set to a predetermined air intake amount (V), and when the DOC inlet exhaust gas temperature reaches the predetermined value (T0) by the DPF regenerating intake throttling, the DPF regenerating processing is started, and when the DPF regenerating processing is not started even when elapsed time reaches a predetermined value (t) after the air intake amount feedback control is started in a state where the DOC inlet exhaust gas temperature does not reach the predetermined value (T0), the air intake amount feedback control is changed to exhaust gas temperature feedback control by the control unit (4), in the exhaust gas temperature feedback control, a target value of DPF regenerating intake throttling is changed to the predetermined DOC inlet exhaust gas temperature (T0) by the control unit (4), when the DOC inlet exhaust gas temperature reaches the predetermined value (T0) by the DPF regenerating intake throttling, the DPF regenerating processing is started, and when application of a load exceeding a predetermined amount is detected before the DOC inlet exhaust gas temperature reaches the predetermined value (T0), the exhaust gas temperature feedback control is returned to the air intake amount feedback control by the control unit (4).