HFM-SFI synchronizing fuel injection and firing order function - GF07.51-P-4009D

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

ENGINE 111.960 in MODEL 124.022 /042 /062 /082

ENGINE 104.942 in MODEL 124.008 /028 /029 /088

ENGINE 104.992 in MODEL 124.032 /052 /066 /092

ENGINE 104.943 in MODEL 129.058 up to 31.7.95

ENGINE 104.991 in MODEL 129.063 up to 31.7.95

ENGINE 104.944 in MODEL 140.028 up to 31.7.95

ENGINE 104.994 in MODEL 140.032 /033 up to 31.7.95

ENGINE 111.945 in MODEL 202.020 /080 up to 31.1.96 with CODE (498) Japanese version

ENGINE 111.961 in MODEL 202.022

Fig 1: HFM-SFI Synchronizing Fuel Injection And Firing Order Function

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Task

When the engine is started, defining the injection sequence in accordance with the firing sequence from the signal supplied by the crankshaft position sensor and camshaft position sensor.

In this way, permitting specific cylinders to be shut off and activation of the knock sensor system to optimize emission levels.

Shown on engine 104

Fig 2: HFM-SFI Control Module (N3/4) Analyzes Functional Diagram (Shown On Engine 104)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Function

The HFM-SFI control module (N3/4) analyzes at engine start the signals from:

crankshaft position sensor (L5)
camshaft position sensor (L5/1)

By comparing the signals supplied by the crankshaft position sensor and camshaft position sensor, the HFM-SFI control module recognizes cylinder "1" and is thus able to assign (synchronize) the injection sequence in accordance with the firing sequence and to actuate the fuel injection valves.

	Crankshaft position sensor position/task/ design/function		GF07.04-P-4116G
	Camshaft position sensor position/task/design/function		GF07.04-P-5035D
	Control module (HFM-SFI) position/task/design/function		GF07.51-P-4103D