Organizations keep those secrets by rationalizing that their behavior is not illegal at all. "This might be against the spirit of the law, but hey, here is this clever loophole that we found." This way, what could have been a perfectly whistle-blowable secret is just a dirty little implementation detail that won't be shared because the people involved are not particularly proud of it. What makes this pattern so powerful is that its persuasiveness does not correlate much with the legal quality of the rationalization: as long as the rationalization is not routinely tested in court, people will happily believe just about anything if it makes their job easier. Doubly so in a corporate environment where optimism is rewarded and pessimism is punished.
Nonetheless it has been very much knowable, for years if not decades, that some level of benchmark-gaming is happening in the car industry. But that's an inconvenient truth to anyone who is living a car centric life, so even people outside of the car industry proper were likely to not make much of it when a car engineer had a spell of loose lips. I am convinced that it is neither a coincidence nor a conspiracy that only a study initiated by a quite car-critical organization could break that wall of motivated disinterest.
Re 40x: a clean combustion combines all the inputs into mostly harmless outputs. Inert gases that have shed all chemically bound energy and won't react much with the molecules that make us alive (unfortunately, we don't know how to perfection that chemical efficiency without sacrificing thermal efficiency). Those mostly harmless gases might still be bad (think CO2), but are not terribly bad as in directly poisonous. In an imperfect combustion, all that stuff can combine into much more reactive and thus dangerous gases. If you set your regulatory threshold sufficiently close to perfection, even a very slight imbalance in the combustion can cause "orders of magnitude beyond threshold". It's the same mathematical principle that makes "many nines" uptime guarantees such a beast: if you fail, you will most probably fail quite hard.
Nonetheless it has been very much knowable, for years if not decades, that some level of benchmark-gaming is happening in the car industry. But that's an inconvenient truth to anyone who is living a car centric life, so even people outside of the car industry proper were likely to not make much of it when a car engineer had a spell of loose lips. I am convinced that it is neither a coincidence nor a conspiracy that only a study initiated by a quite car-critical organization could break that wall of motivated disinterest.
Re 40x: a clean combustion combines all the inputs into mostly harmless outputs. Inert gases that have shed all chemically bound energy and won't react much with the molecules that make us alive (unfortunately, we don't know how to perfection that chemical efficiency without sacrificing thermal efficiency). Those mostly harmless gases might still be bad (think CO2), but are not terribly bad as in directly poisonous. In an imperfect combustion, all that stuff can combine into much more reactive and thus dangerous gases. If you set your regulatory threshold sufficiently close to perfection, even a very slight imbalance in the combustion can cause "orders of magnitude beyond threshold". It's the same mathematical principle that makes "many nines" uptime guarantees such a beast: if you fail, you will most probably fail quite hard.