Fresh Air Bypass to Cool Down Hot Exhaust in DPF Regeneration Mode at Low Vehicle Speed and Idle
An engine system includes a diesel engine having an exhaust manifold connected to the diesel engine. An exhaust passage is connected to the exhaust manifold and a diesel particulate filter is disposed in the exhaust passage. An air intake passage is provided for supplying fresh air to the diesel engine. A bypass passage is connected between the air intake passage and the exhaust passage in a location downstream of the diesel particulate filter. The bypass passage includes a bypass control valve for opening and closing the bypass passage during a diesel particulate filter regeneration cycle when the vehicle is at low speed or idle.
1 . An engine system, comprising:
a diesel engine;
an exhaust passage in communication with an exhaust gas from the diesel engine;
a diesel particulate filter disposed in the exhaust passage;
an air intake passage for supplying air to the diesel engine; and
a bypass passage connected between the air intake passage and the exhaust passage at a location downstream of the diesel particulate filter, the bypass passage including a bypass control valve for opening and closing the bypass passage.
2 . The engine system of claim 1 , further comprising a turbocharger that provides compressed air to the air intake passage.
3 . The engine system according to claim 2 , wherein the turbocharger provides the compressed air to a charger cooler, the bypass passage being connected to the air intake passage downstream of the charger cooler.
4 . The engine system according to claim 2 , wherein the turbocharger provides the compressed air to a charger cooler, the bypass passage being connected to the air intake passage downstream of the turbocharger and upstream of the charger cooler.
5 . The engine system of claim 2 , wherein the compressed air is provided to the bypass passage, the compressed air being at a pressure that is greater than a pressure of exhaust gas in the exhaust gas passage at the location downstream of the diesel particulate filter.
6 . The engine system according to claim 1 , wherein the air intake passage includes an intake throttle valve downstream of the bypass passage.
7 . The engine system according to claim 1 , further comprising an engine controller for periodically operating the engine system in a diesel particulate filter regeneration mode and for opening the bypass control valve during the diesel particulate filter regeneration mode.
8 . The engine system according to claim 1 , further comprising an engine controller for periodically operating the engine system in a diesel particulate filter regeneration mode and for opening the bypass valve when the engine is in the diesel particulate filter regeneration mode and the engine is at idle.
9 . The engine system according to claim 1 , further comprising an engine controller for periodically operating the engine system in a diesel particulate filter regeneration mode and for causing the bypass valve to open when the engine is in the diesel particulate filter regeneration mode and the engine is driving a vehicle at a speed of 5 miles per hour or less.
10 . An exhaust treatment system for an engine, comprising:
an exhaust passage adapted to be connected to the engine;
a diesel particulate filter disposed in the exhaust passage;
an air intake passage adapted for supplying air to the engine;
a bypass passage connected between the air intake passage and the exhaust passage at a location downstream of the diesel particulate filter, the bypass passage including a bypass control valve for opening and closing the bypass passage.
11 . The exhaust treatment system according to claim 10 , further comprising a turbocharger that provides compressed air to the air intake passage
12 . The exhaust treatment system according to claim 11 , wherein said turbocharger provides the compressed air to a charger cooler, the bypass passage being connected to the air intake passage downstream of the charger cooler.
13 . The exhaust treatment system according to claim 11 , wherein the turbocharger provides the compressed air to a charger cooler, the bypass passage being connected to the air intake passage downstream of the turbocharger and upstream of the charger cooler.
14 . The exhaust treatment system according to claim 11 , wherein the compressed air is provided to the bypass passage, the compressed air being at a pressure that is greater than a pressure of exhaust gas in the exhaust gas passage at the location downstream of the diesel particulate filter.
15 . The exhaust treatment system according to claim 10 , wherein the air intake passage includes an intake throttle valve downstream of the bypass passage.
16 . A method comprising:
regenerating a diesel particulate filter that is in communication with an exhaust gas from a diesel engine; and
providing communication between an intake air source and the exhaust gas at a location downstream of the diesel particulate filter during the regenerating.
17 . The method of claim 16 , further comprising compressing air supplied to the intake air source and providing the compressed air to the location downstream of the diesel particulate filter.