General Information; Application; Terminology; Delivery Specification - Bosch RTM 430 Description Of The Unit

3.

General information

3.1

Application

The RTM 430 smoke opacity module serves the measurement of
emissions (smoke emission) for diesel vehicles.
The RTM 430 can only be used in conjunction with the following
device versions:
– Emission System Analysis (ESA),
– Bosch Emissions Analysis (BEA) or
– Emissions Analysis Tester (EAM).
3.2

Terminology

The effective measuring length is the light distance, which is
passed through by the smoke. It amounts to 430 mm.
The degree of opacity [%] and coefficient of absorption
[1/m] represent a dimension for the quantity of light, which is
weakened (absorbed) by soot, white smoke and blue smoke.
The mass concentration [mg/m
volume in mg, which is emitted by diesel vehicles in relation to
1 m of exhaust gas.
3
i Conversion of the coefficient of absorption into mass
concentration is based on the conversion table compiled by
the British Motor Industry Research Association (MIRA).
4.

Delivery specification

RTM 430 - 1 687 022 413:
– RTM 430 connecting cable (6 m)
– Car exhaust-sample probe
– Exhaust-sample hose, Ø 10 mm, length 1 m
– Calibration pin
– Cleaning brush
– Operating instructions
– Installation instructions
RTM 430 –1 687 022 599:
– Cleaning brush
– Operating instructions
– Installation instructions
16
] indicates the particulate
3
5.

Functional description

The RTM 430 serves the recording of the coefficient of absorption
k [1/m] of the exhaust gas for compression ignition engines
(diesel engines). To this end, during the measurement, while
accelerating, a portion of the exhaust gas from the vehicle's
exhaust tailpipe is routed via an exhaust-sample probe and a
measuring chamber sample hose (without any suction support).
The opacity is measured, which in turn is used to calculate the
coefficient of absorption.
Exhaust-sample probe:
– The exhaust sample probes are designed such that exhaust
sampling can be conducted on all the various shapes of exhaust
tailpipes. The adjuster mechanism enables a minimum
immersion depth into the exhaust pipe of 5 cm to be assured.
– Furthermore, the design also ensures that a minimum distance
of 10 mm to the inner exhaust-pipe wall is given.
Measuring chamber:
– In order to measure the opacity an optical sender (LED) emits
green light, which is partly absorbed by the exhaust gas in the
measuring chamber.
– The non-absorbed portion of light arrives at the receiver
(photodiode) and converts the optical signals into electronic
data.
– Soot deposits at the optical windows are avoided by means of
air curtains (blow-by purge air).
– In order to avoid having any condensation on the walls of the
measuring chamber and to keep the exhaust-gas temperature
above the dew point, the measuring chamber is equipped with
a heater.
– The null compensation runs automatically.
Correct operation:
– In order to guarantee correct operation, the exhaust-gas
temperature and the measuring chamber temperature are
constantly monitored.
– In addition to this, prior to each measuring cycle a null
compensation process
contamination level of the optical measurement path is also
checked.
Measurement can no longer take place if one of the stated
parameters is outside the permissible tolerance.
is performed, whereby the