Page 149 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

Chapter 1.6

Honda Motor Co. Ltd.

The methods proposed by Honda have been applied, except where otherwise mentioned, for an
engine layout similar to that of fig. 62.
Connected to the cylinder block of the engine is an intake pipe across which is arranged a
throttle body accommodating a throttle valve therein. A throttle valve opening (e) sensor is
connected to the throttle valve for generating an electric signal indicative of the sensed throttle
valve opening and supplying same to an electronic control unit (hereinafter called "the ECU").

Fuel injection valves, only one of which is shown, are inserted into the interior of the intake
pipe at locations intermediate between the cylinder block of the engine and the throttle valve
and slightly upstream of respective intake valves, not shown. The fuel injection valves are
connected to a fuel pump, not shown, and electrically connected to the ECU to have their
valve opening periods controlled by signals therefrom.

On the other hand, an intake pipe absolute pressure sensor is provided in communication with
the interior of the intake pipe through a conduit at a location immediately downstream of the

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