- 01.12.2025, 09:52
#583384
Hi,
The term
"Saginaw pump" likely refers to the secondary air injection pump (also known as an A.I.R. pump or "smog pump") used in the exhaust emission control system of the Mercedes-Benz Model 280S/8. Saginaw is a common manufacturer of such pumps, particularly for vehicles from that era.
The function of this pump is to reduce harmful emissions (specifically unburned hydrocarbons and carbon monoxide) during a cold start.
Role in the Emission Control System
Air Injection: During the engine's warm-up phase, which typically involves a rich air-fuel mixture to ensure smooth operation, the air pump draws in ambient air and injects it into the exhaust manifold, downstream of the exhaust valves.
Oxidation (Afterburning): The added oxygen in the exhaust stream causes a secondary burn (oxidation) of the unburned fuel and carbon monoxide, converting them into less harmful carbon dioxide and water.
Catalytic Converter Efficiency: The heat generated by this afterburning process helps the catalytic converter reach its optimal operating temperature faster, allowing it to work efficiently sooner.
The pump typically only runs for a short period (around 2-3 minutes) after a cold engine start, after which it is shut off by the engine control unit. While the pump is not essential for the engine to run, it is a critical component for meeting emissions standards.
best regards Götz
The term
"Saginaw pump" likely refers to the secondary air injection pump (also known as an A.I.R. pump or "smog pump") used in the exhaust emission control system of the Mercedes-Benz Model 280S/8. Saginaw is a common manufacturer of such pumps, particularly for vehicles from that era.
The function of this pump is to reduce harmful emissions (specifically unburned hydrocarbons and carbon monoxide) during a cold start.
Role in the Emission Control System
Air Injection: During the engine's warm-up phase, which typically involves a rich air-fuel mixture to ensure smooth operation, the air pump draws in ambient air and injects it into the exhaust manifold, downstream of the exhaust valves.
Oxidation (Afterburning): The added oxygen in the exhaust stream causes a secondary burn (oxidation) of the unburned fuel and carbon monoxide, converting them into less harmful carbon dioxide and water.
Catalytic Converter Efficiency: The heat generated by this afterburning process helps the catalytic converter reach its optimal operating temperature faster, allowing it to work efficiently sooner.
The pump typically only runs for a short period (around 2-3 minutes) after a cold engine start, after which it is shut off by the engine control unit. While the pump is not essential for the engine to run, it is a critical component for meeting emissions standards.
best regards Götz
Gruß Götz
aus Altlandsberg UCG 5956
Membership No: 663 The Old Wheelers Club of Namibia
aus Altlandsberg UCG 5956
Membership No: 663 The Old Wheelers Club of Namibia
- von Jaeger25