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Video Outs. Mixture Prep.
Video Mixture Preparation
Video Air Filter
Video History Injection
Video Petrol Injection
Video Single Point Injection
Video Multi Point Injection
Video Intake Mixt. Heating
Video Elektr. Eng. Managem.
Video Exhaust Gas Treatm.
Video On Board Diagnosis
Video Adjust. Intake Manif. 1
Video Adjust. Intake Manif. 2
Video Intake Air System
Video Cylinder deactivation 1
Video Cylinder deactivation 2
Video Cylinder deactivation 3
Video Petrol
Video Induct. Pulse Gener.
Video Lambda Sensor
Video Lambda s. voltage meas.
Video Lambda sensor Diesel
Video Thermo Time Switch
Video Side channel pump
Video Peripheral pump
Video Diaphragm pump
Video Roller Vane Pump
Video Carburetor
Video Oil-bath Air Filter
Video Unreg. Intake Air

Video Fuel 1
Video Fuel 2

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Intake Fuel-mixture Heating


The multipoint injection requires no intake mixture pre-heating because this is formed only at the end of the inlet manifold or in the combustion chamber. It is only meaningful, in engines whose mixture is formed at the beginning of the inlet manifold, as in the case of the central injection, the single carburetor and the register carburettor. Here the fuel can condense on the cold walls of the inlet manifold thus, causing a certain amount of the ignitable mixture to be lost. This means that, during, and after cold starting, the mixture has to be made richer, which is reflected particularly, in a higher hydrocarbon content in the exhaust gas, and of course, in higher engine wear-and-tear and fuel consumption.


Mostly, directly below the throttle-valve(s), before the inlet manifold fans out to the individual cylinders, a "hedgehog" type element is mounted below. It's "quills" reach deep into the inlet manifold cross section. It is, first of all, electrically heated with a high amont of current (approx. 30 A), thus quickly warming the fuel-air mixture. Thereby, the condensation on the cylinder-walls is reduced.
Through the PTC-character of the electric mixture-pre-heating, the current requirement drops with the warming up. The component can be switched off when, either the coolant takes over the heating, or if the heating is no longer necessary. This is because a heated inlet manifold in an engine that is already warm, causes a loss in performance and efficiency. By the way, care should be taken, not to leave the ignition switched on for longer periods without starting the engine. If the control device is not fitted with a suitable cut-off circuit, the battery will discharge in a relatively short time. 05/10               Top of page               Index
2001-2015 Copyright programs, texts, animations, pictures: H. Huppertz - E-Mail
Translator: Don Leslie - Email:

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