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mpgJuan
USA, Earth
Research Engineer, expertise in light-duty fuel economy
Interests: vehicle efficiency, fuel economy regulations, fuels, emissions, catalysis,
Recent Activity
The US has the safest vehicles and the cleanest vehicles (for CO, HC, NOx emissions). They could be lighter and slower, but the consumer chooses larger and faster. SUVs are very popular but have more drag and electrified vehicles are available but are a small part of sales. Stiffer regulations could force vehicles that are liked less but use less fuel or high fuel prices could swing the market as well. The fuel economy gains since about 2004 are substantial in any case.
The issues are not simple. The regulations for 2022-2025 left unchanged will rapidly push a large amount of electrified powertrains into the market, a trend previously underestimated by EPA (see the mid-term review and refereed papers on this subject). This pits initial cost of vehicles against the regulated rapid rise in fuel economy. Apart from significantly greater cost, there is a physics "beauty" to hybridization, with regenerative braking becoming an energy "source" vs. friction braking that turns vehicle kinetic energy into heat. Those who wish to defend the current (but likely to change) 2022-2025 CAFE standards need to make the careful, compelling honest arguments why they are a net "good." It can probably be done. In any case the OEMs will meet CAFE - they have to!
It will be interesting to see how successful the autos will be in meeting the standards through 2021 (seems these will be preserved) which will not be as easy as some think. The standards beyond 2021 will greatly influence the extent to which hybrid powertrains (in their various) forms will need to be pushed into the market.
It would be informative to know from Nissan more about the thermal efficiency gain for this engine over similar engines - for the city and highway cycles. The % gain in mpg almost certainly is dominated by downsizing from a 3.7 liter engine to a 2.0 liter turbocharged engine. It would be nice if commenters kept on topic, but I will note that in the US, the OEMs design to a lot of safety standards and the high expectations of the purchasers. If practical vehicle mpgs of 120 were actually attainable, they would appear in select markets somewhere in the world.
The "US" OEMs are essentailly worldwide companies that design and sell in Europe and elsewhere and will continue to develop higher mileage vehicles including electrified powertrain vehicles of many types. The current CAFE standards through 2021 will be rather challenging for gasoline powertrain vehicles. Sedans can meet the standard (a few do already) with Vans, SUVs and trucks having a greater challenge. If the 2022-2025 standards remain intact we should see a very significant rise in electrified powertrains.
The regulations are footprint based targets, and improvements in vehicles will continue. The OEMs will need to meet the targets on an OEM ensemble-fleet basis. Some will purchase credit from others, but this only goes so far. The standards will keep "forcing the issue" and what is offered for sale will keep changing towards higher fuel economy models. It will not be a slow process if the regulations remain unaltered.
In the US CAFE/CO2 regulations will force this type of system or other electrified powertrains into the market. It is certainly not happening by consumer demand at this time. CAFE compliance will be a very hard driver for certain OEMs in a few years. Mild hybrids may prove to be the most cost effective route to compliance.
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Apr 1, 2016