Electrification of Vehicles – Gain much thanks to that?

By Rud Istvan,

This possible post was inspired by Andy May’s recently mainly related to internal combustion engine (ICE) alternatives. Since I am a SME in the general field (including some basic supercapacitor patents), I thought I would provide some practical technical perspective for WUWT.

First, internal combustion engines come in two basic forms: internal and external. Externally (1819, Sterling) never proved to be a reality although recently Dean Kamen was trying to invite me to become Motorola’s head of strategy and innovation at the time for an investment. His basic engineering problem is simple. In the ICE, most of the required thermodynamically cooled exhaust heat escapes through the exhaust manifold. The rest (about 20%) is in the large car radiator. In Sterling ECE, ALL active waste heat must escape through a REALLY BIG heatsink. ARE NOT.

Second, ICE engines have different types of stroke. For the purposes of this simple discussion, there are only two parts: the Otto cycle and the Atkinson cycle. The Otto cycle is your usual 4-piston car. An upward compressed fuel, a lower combustion, an upward stroke of the exhaust, then an intake fuel in the lower lane.

An Atkinson cycle uses the same four slightly different piles. The amount of air that is compressed up varies (via complex valve timing). So that gives more fuel efficiency (about 15%) but less torque efficiency at lower combustion. (Oversimplified explanation: more air absorbed, less fuel, less combustion torque.)

In what follows, we learn the full hybrid can fully make up for that shortfall in torque-saving Atkinson cycle fuel economy.

Crossbred

There are several flavors:

1. Bland
2. Medium
3. Full (Prius)
4. Plug in (New Prius, Chevy Volt)

We’ll define them all, but only look at how full and plugged in.

1. Mild hybrids basically just shut down the engine at idle. It’s NOT straightforward with a conventional automatic transmission, that’s why FORD went all in with the DCT in 2018. Now this also (as BMW learned) still kills SLA battery life despite having the DCT. . It turned out that the extra AH battery size needed (even if the PbA battery cost was low) “killed” that simple application. Valeo’s system is just a ‘dead’ example.
2. Moderate hybrid add regen brake. The point is, unless the battery is really big, regen kills PbA even if PbA is oversized to begin with) battery life by ‘overcharging’. Also kill that app.
3. Full hybrid work, as posted here before. Reducing the size of the ICE (mine is a small I4 Atkinson cycle), produces a torque loss with the electric machine. Not stopping at the stop is free and the regen brake is free. For comparison, the HP-equivalent Ford Escape V6 4WD and 2007 towing averaged around 20 MPG, our full hybrid getting around 30. Also, we use the used hitest. normally, equivalent to v6. The difference is about a gallon in these parts, and about 1/3 of a gallon less for an HP compact SUV and comparable towing.
4. Complementary. (like the Chevy Volt and the new Prius plug-in). These batteries are, by definition, larger, more expensive, and heavier, but still have all sorts of heavy-duty range-extending spare ICE devices. At the present time, rising (unnecessarily) gasoline prices are still a very bad economic trade-off. And, there is a subtle concealment. In the full hybrid versions, the traction battery will float for between 60% and 40% charge. Never more, never less. That maximizes its lifespan by design.

When plugged in, you will drain the battery until the charging motor stops. That ensures much shorter battery life. Not a good thing economically.