Automakers first deployed these fuel-saving technologies on hybrids and pricey models. But you’ll soon see them on most daily drivers.
Automakers are hard at work developing big changes to our cars, trucks, and SUVs. Full electrification and autonomous driving modes are the most important of these major disruptions to the car as we know it. However, before we are all being driven around in battery-electrics we have years or decades ahead of liquid-fueled vehicles to look forward to. Every car company, from the largest to the smallest, is beginning to deploy fuel savings systems and techniques to mainstream vehicles that were first debuted on hybrids and EVs. Here are six you can expect to see in your next new vehicle.
Unlike a constantly variable transmission or a hybrid drive system, stop-start technology does not provide a huge bump in noticeable MPG savings in real-world driving. It was never intended to. The EPA says the fuel savings can be as much (or as little) as 4-5%. Rather than a system that provides a noticeable effect, stop-start is a big numbers system. By eliminating fuel used during brief stops in our daily driving, stop-start technology saves fuel a few drops at a time. The idea is that if we can save a few drops per day from each of the approximately quarter-billion vehicles on the road in America, the drops add up to millions of gallons of fuel. Like many fuel-saving technologies, automakers are rewarded for adding these types of systems in the highly complex government Corporate Average Fuel Economy ratings system and the rewards can add up.
Stop-start began in hybrids like the Prius but has now found its way to the most common vehicle in America, the pickup truck. Ford went first, and Chevy follows the lead with the all-new 2019 Silverado. Stop-start is now part of many of the everyday vehicles BestRide tests. The method by which the goal is achieved is not the same for all vehicles. In some, the feeling is very noticeable and in others, like a BMW 740e sedan we just tested, almost undetectable. Like most technologies, automakers will figure out the perfect solution after trying a few things and the driving public will adapt. We’ve started to tune it out and you will too after a few weeks of trying it.
The problem with auto stop-start systems on most vehicles in the marketplace today is that they’re limited by an already taxed 12-volt electrical system. 12-volt systems only have a 3kw practical power limit, and most of that power is devoted essential electronic systems that keep the car running.
But over the next decade, 60 million cars are expected to feature a 48-volt electrical system, with a 10kw practical power limit, which will introduce the next generation of auto stop-start. They’re called “mild hybrid” vehicles, but they’re really just a more advanced auto stop-start system that allows the engine to turn off not only when stopped, but when coasting. Mild hybrid technology is what allows Volvo to suggest that it will no longer sell cars powered solely by internal combustion after 2020.
New Transmission Options
One of the biggest single changes with regard to fuel economy savings has been modern transmission options. Decades ago, automakers started using more and more gears to achieve better results. The 2002 Honda Accord used four gears in its automatic transmission. The 2003 Accord used five. The new 2018 Accord 2.0T uses ten. Daily drivers, trucks, and sports cars all use eight or more gears in almost every new vehicle. That is, if they have gears at all.
Constantly variable transmissions like those found in the Toyota Corolla, Honda Civic, Honda Accord (base engine), almost all Subarus, and of course, most hybrids, save fuel by eliminating the shifting completely and by increasing the total ratio spread available. CVTs had been the defacto fuel-sipping transmission choice for automakers, but things are changing. In Lexus’ newest UX crossover the company uses a CVT augmented with a low-speed gear change. Hyundai has found that in its hybrids dual-clutch automatics work very well with low-speed electric power to solve that transmission’s biggest drawback. Regardless of what transmission choice an automaker opts for, one thing is certain; Manuals are starting to go away in mainstream cars. They are still found here and there, but automakers produce them in small numbers on the limited models they still offer them on.
Braking Energy Recapture & Battery Charging
Full hybrids use a holistic approach to saving fuel, but one technology brings the biggest results. Capturing part of the energy lost to braking is by far the biggest factor for both hybrids and also an electric vehicle’s impressive efficiency. All green vehicles reply on brake energy regeneration to power batteries that then help move the vehicle. More and more everyday vehicles will become hybrid models, but before they do automakers will adopt a more subtle approach.
Automakers like BMW and Mazda have already found that by better timing the charging of the vehicle’s 12-Volt battery losses due to the alternator being powered by the engine can be minimized. We predict that these small gains will be part of every new design at some point in the near future. Mazda calls its system i-ELOOP. BMW calls its system EfficientDynamics.
There has already been a major shift to alternative materials like aluminum and magnesium in place of steel. An even bigger revolution is taking place in the steel automakers use to reduce weight in key areas by using advanced alloys. Metals will always make up the foundation of mainstream vehicles, but composites are beginning to become part of everyday vehicles as well. Non-metallic body panels go back to the 1950s. The Corvette is one of the most easily recognizable vehicles that use composites, but Corvettes are not really mainstream. GMC Sierra trucks are, and for 2019 GMC is introducing a carbon-fiber composite bed in place of steel. The Toyota Tacoma and Honda Ridgeline have used composite beds for years, and now the big truck makers are starting to follow their lead. As time goes on, watch for composites to appear in crossover tailgates, as structural elements, and possibly even wheels.
Once reserved for large engines like the V8s used in trucks, cylinder deactivation is coming to all vehicles soon. The four-cylinder 2018 Mazda CX-5 compact crossover uses cylinder deactivation and saw a 1 MPG City and Highway bump in its MPG rating when the system was added. Chevy’s Silverado uses the technology in its new 2019 model. The system has evolved so far it can now stop the fuel to all but one cylinder.
Like stop-start, using glass tinted to reduce the amount of solar heating inside a vehicle is not going to be something a driver will notice at the pump. However, the energy consumed by air conditioning systems driven by a belt off the crankshaft of a car’s engine is significant when added up over the entire U.S. fleet. Government regulators give automakers a small boost to their corporate average fuel economy ratings by doing small things like adding glass with a tint that reduces solar energy (heat) inside the cabin. Given that the government also had to implement laws restricting how dark glass tints can be, we are guessing this is one technology few drivers will object to.