The worst aspect of the Bosch/VW diesel cheat was delaying searching for an honest solution to the diesel problems. Probably around 2005-06, Bosch wrote the control laws that detected 'testing mode' that hide the true diesel NOx problem. Then VW used it to make 'clean diesels' which in reality were 'cheat diesels.' I still wonder how the cheating engineers and their managers could think so little about their lungs and their kids and families. They went to the extreme of trying to run a bogus diesel exhaust experiment (i.e., exposing primates to 'cheat' diesel exhaust versus a +5 year old, used, USA pickup diesel.) Portable emissions testing equipment is a recent technology that let the engineers see what emissions are in real life. Augmenting dynamometer labs, portable emissions testing is what blew the whistle on the cheat. But it also struck Bosch with a 'clue by four' as they finally realized what they were doing in real life to their own families and people: Cheat diesels have and are becoming impossible. Then I read this recent Bosch paper: http://www.autonews.com/assets/pdf/bosch-nox-report.pdf . . . To warm up the exhaust system after the start: Increasing the temperature of the catalysts as quickly as possible through engine-related measures – which may have an impact on fuel economy. As long as the warm-up measures are required (i.e. target catalyst temperature not reached yet) the engine-out emissions, especially NOx, but also HC and CO, should be as low as possible. To maintain the temperature once the exhaust system has warmed up: Preventing the catalysts from cooling down or reducing that effect caused by the ex- haust-gas flow from the engine (which is colder than the current catalyst temperature during phases of overrun or low load); preferably this is to be achieved by minimizing the flow rate in the exhaust system. The fuel penalty of all measures taken has to be kept at a minimum. If the temperature in the exhaust system is very high during an overrun or low load phase, no measures reducing the flow rate are initiated because a certain tempera- ture reduction is desired in this case. Systematic shut-down of the engine during idling as far as possible. What they discovered is chemical processes are sensitive to temperature. Manage the temperatures and tolerable NOx levels can be achieved. The full paper is worth a read and given the lead time, 4-5 years, not likely to show up in Bosch controlled diesels anytime soon. But they lost 20 years from 2005-06 due to the cheat. I drive a BMW i3-REx with a two cylinder, gas engine which is a perfect application for a small diesel. Bosch now knows how to solve the problem so perhaps future plug-in hybrids will marry the two technologies. Understand, I have no interest in a gas-only or diesel-only vehicle, they just don't make sense compared to a plug-in hybrid. Bob Wilson
