ACtion Magazine - Napa Special Edition - June 2017 - 22

Hybrid and battery electric vehicle A/C
The world's first hybrid minivan
Although Chrysler is not often thought of for fuel-sipping, ecofriendly cars (they're better known for muscle and power featured
in 707 HP Charger and Challenger, and Ram Trucks), FCA has successfully sold Fiat 500e BEVs since 2013 in California and are set to
release the world's first hybrid minivan early this year.

Ever wonder which A/C oil you should use with an HEV,
BEV, yf, or even an R-134a vehicle? Many of us would like
the OEMs to narrow it down to just a few (or maybe one),
but the proper oil is vehicle specific, and must be verified
before use.
Some recommendations from Fiat Chrysler Automobiles:
* R-1234yf vehicles require new compressor oils.
* DO NOT use R-134a PAG oil in R-1234yf systems. It
lacks a required acid reducer.
* Denso compressors use ND-12 PAG (Mopar P/N
68224150AB), which is backwards compatible with some
R-134a systems that use ND-8.
* Halla/Visteon compressors use FD46XG oil (Mopar P/N
05114554AB)
* Delphi compressors use PS-D1 oil (Mopar P/N
68232939AB)

BEV A/C
Nissan and Tesla have led the way as number 1 and 2 highest production volume BEV manufacturers with close to 425,000 vehicles
built between them. GM, however, will likely jump into second place
soon after it ramps up the long-awaited Bolt to perhaps 20,000 or
30,000 in the first year. And they're not the only ones going all-electric. Mercedes projects its Generation EQ lineup to be on the market
by 2020, along with VW's I.D. family of BEVs.
How cabin temperatures are controlled in these vehicles is still
evolving. The earliest systems were adapted from their HEV cousins,
basically using an electric compressor and glycol heater coupled with
electric pumps and a conventional HVAC case under the dash, sometimes split off to also heat and cool the battery. But things may soon
change if a new Denso system begins to gain traction.

Can A/C extend EV range?
Much of the technology that goes into hybrid and electric vehicles
comes from Tier 1 suppliers like Denso, who builds A/C components and
systems for countless vehicles around the world. A/C systems are usually
a drain on fuel economy and range, but one of the newest we're looking
forward to seeing on production models is the Denso heat pump system
which is said to be much more efficient.
Because cabin heaters traditionally work off the residual heat from
engine coolant, we usually think of it as something we get for free. But

ACTION/NAPA * Spring 2017

Figure 4: BMW claims a 50% increase in efﬁciency compared with conventional heating systems and a 30%
increase in driving range too. It has had a heat pump on
i3 models without the Range Extender since 2014.
that's not the case on many electric cars. In fact, the PTC heater is one of
today's most power-hungry accessories, one that can use up to 50% of the
battery and reduce driving range. Heat pump air conditioners (widely used
in homes) offer the most efficient heat source, providing more warmth
and using less electricity by drawing heat from the ambient environment
(which contains nearly unlimited thermal energy).
Denso's system uses an external heat exchanger as an evaporator in
the air-heating mode to extract thermal energy from the atmosphere. It
transfers this heat to the refrigerant, which is at a lower temperature than
ambient.
Air-heating operation:
* The compressor compresses low-temperature,
low-pressure gas refrigerant into high-temperature,
high-pressure gas refrigerant.
* The high-temperature, high-pressure gas refrigerant warms the vehicle cabin by releasing its heat
to the cabin air as it passes through the internal
condenser while it is cooled and condensed into a
liquid.
* The liquified refrigerant expands across the airheating expansion valve into a low-temperature,
low-pressure gas-liquid two-phase refrigerant, and
then extracts thermal energy from the atmosphere
via the external heat exchanger and flows back into
the compressor.

Table of Contents for the Digital Edition of ACtion Magazine - Napa Special Edition - June 2017