3
9, the oxygen sensor and the nitrogen oxygen sensor in air in life expectancy for two years
and 14 months. ( over the duration of accuracy will drop )
10, power: AC100-240V50/60HZ or DC12V ( matching power inverter )
11, power consumption: <40VA
12, dimensions: 420mm ( long )× 310mm ( W)× 170mm ( high )
13, weight: 9kg
IV. Principle of operation:
The test of HC, CO and CO
2
via HPC500/400 Auto Exhaust Analyser, which adopts
nondispersive infrared ray analytical method (NDIR), is based on the principle that
different gases selectively absorb infrared rays.
The Instrument, by adopting narrowband infrared interference filter, is capable of
analysing the content of required gas from tested gas, and therefore has good selectivity.
First inject a series of staition gas with different concentration into test chamber of the
instrument to get a standard curve of gas concentration and output voltage and save it in
computer. Inject exhaust gas to be tested into test chamber and then test its relevant
voltage value and compare it with the standard curve saved in computer to get correct
concentration value of tested gas.
For test of HC, CO and CO
2
, the instrument adopts the same light source and the same
detector. Its circuit adopts advanced technologies, e.g. AGC circuit, micro-processing
computing technology and automatic zeroing, etc. It can display instantaneous value and
also can display average concentration value as required by national inspection code.
Data can be either displayed from front panel or PRTed out. As required by users its back
panel has output interface so that it can be connected with computer.
An oxygen sensor is adopted for testing oxygen concentration. Its output electric current
has linearity relationship with oxygen concentration, from which oxygen concentration can
be tested.
In order to know auto combustion and whether the exhaust has leakage, the instrument
can also displays excessive air coefficient λ and carbon monoxide (CO) emendation value
(COcor), which are related to combustion. Gasoline, LPG and methane have different