Hi,
The name of the variable in setName is different from the name you are using in the rules. The names cannot have spaces.
As for defuzzify, the current version returns void. To get the value, you have to do LevelOfCongestion.getOutputValue() after the engine has been processed.
Gaussian and Triangle are different linguistic terms. Please check QtFuzzyLite and observe the differences between the different linguistic terms.
Cheers,
Juan.