ECM egrCAN, Инструкция по эксплуатации, Страница: 19 / 52

15
Processing Data in Host Data Acquisition System
The egrCAN system will output the following parameters at the programmed broadcast rate:
1. The %O2 in air, the %O2 in the intake manifold, the %O2 in the exhaust
2. Lambda operating point of the engine
3. The barometric pressure, intake pressure, and exhaust pressure.
%EGR can be calculated via the following formula in the host data acquisition system:
%EGR = 100 · (O2air - O2int) / (O2air – O2exh) [Equation 1]
where:
O2air = Parameter O2 (%O2) output by the “air” module.
O2int = Parameter O2 (%O2) output by an “intake” module. An egrCAN system can have
multiple intake modules. Thus multiple %EGRs can be reported for different
locations (for EGR distribution studies) or stages (for multi-stage EGR
systems).
O2exh = Parameter O2 (%O2) output by an “exhaust” module.
Sometimes it is useful to average the calculated %EGR. The following recursive averaging
filter is easy to perform in real-time:
Averaged%EGR
t
= α x %EGR
t
+ (1 – α ) x Averaged%EGR
t-1
where:
Averaged%EGR
t
= the updated average %EGR value
α = The user-programmable averaging.
Range: 0.001 (heavy averaging) to 1.000 (no averaging).
Recommended: 0.293
%EGR
t
= the latest %EGR value calculated via Equation 1
Averaged%EGR
t-1
= the previous average %EGR value