IRVINE, CALIFORNIA – It’s always news when an automaker dramatically improves its fuel economy – and that’s when it’s in single digits. So how about 20 per cent instead?
Mazda has a new engine technology it says could even go as high as a 30 per cent improvement over its current gas engines. And you’ll get more torque, at a wider range of engine speeds, and do it all on regular-grade fuel. It’s called Spark Controlled Compression Ignition, or SCCI, and if you like engine tech, you’re going to love this.
And yet, for all that improved performance at the pump, it still won’t get Mazda off the hook with governments that want drivers to go electric. In Quebec, Mazda will owe millions of dollars this year in penalties because it only runs on gasoline – but more on that later.
I drove one of these engines in a test mule for a couple of hours on city streets and California highways. My ride combined the next-generation Mazda3’s chassis, the new engine – in Mazda-speak, it’s called SkyActiv-X – and incredibly comfy new high-density seats that are also coming to showrooms, all of it disguised under a current Mazda3 shell. For gutsy performance and smooth operation, this engine is everything Mazda says it is.
The plan is to eventually roll out the technology across all of Mazda’s vehicles worldwide. It’ll first be used sometime in 2019, although we don’t yet know which markets will get it first.
In simplest terms, the SkyActiv-X engine combines the basic principles of diesel and gasoline engine operation into one. Diesels depend on compression to provide heat for combustion, while gasoline engines use a spark. It is possible to ignite a gasoline-air mixture by squeezing it until it’s hot enough to spontaneously combust – known as Homogenous Charge Compression Ignition, or HCCI – but it’s very hard to get it right.
The big issue is controlling when the volatile mixture ignites. If it lights at the wrong time, the engine won’t run properly, and can potentially damage itself. While HCCI can work under ideal circumstances, all that goes the window if the ambient temperature, humidity, or altitude changes – in other words, if the car’s driven in the real world.
Mazda solved it by adding spark plugs. The engine has an extremely high 16:1 compression ratio, but the fuel mixture is so lean that even when it’s compressed, there’s too much air for it to properly ignite on its own. It’s not even rich enough to ignite with a spark, and so it’s swirled to create a vortex that concentrates just enough fuel to the spark plug.
The resulting tiny fireball starts the combustion. The quick energy release increases the force of the piston’s power stroke for more usable torque, especially at lower engine speeds, but the ultra-lean mixture reduces fuel consumption.
High-compression engines are prone to knock. In this engine, fuel is injected during the compression stroke, rather than the intake stroke, so it stays cooler to help prevent pre-ignition. Each piston has a pressure sensor that continuously monitors combustion, and adjusts the spark timing if necessary. This allows the engine to operate over a wide range of ambient conditions, whether in sunny California or the wintery Yukon.
Some of the engine’s technologies weren’t available to engineers in the past, including super-fast microprocessors. Mazda also says the company’s size made it easier to figure out the process. “We tackled it holistically, and we can do that because we’re a smaller operation,” said Dave Coleman, manager of vehicle dynamics engineering. “If we want something changed, we just walk next door and tell the engineers to do it. Big companies have so many different divisions, and they don’t always work together like that.”
Of course, for all the pros, there are cons. Some of the hardware is very expensive, including the pressure sensors. And SCCI is noisy. Mazda tones it down by encasing the engine in sound-deadening material. Technicians will have to remove that to do engine repairs, and that’s going to add time and cash to your bill.
But what’s really burning Mazda’s butt is that for all this, it still has to electrify. Currently, its overall corporate average fuel economy – the famous CAFE in consumption ratings, meaning the combined fuel numbers of all models an automaker makes – is the best of all automakers in EPA testing.
Granted, it doesn’t have full-size pickup trucks drinking hard at the top end, but Robert Davis, senior vice-president of special assignments, says Mazda sets the record because the company has applied fuel-saving technologies to all its vehicles. “We don’t make a small number of super-efficient cars to offset a larger number of non-fuel-efficient cars,” he said. “Our fundamental philosophy is ‘right-size displacement.’”
This means putting an appropriately-sized, naturally-aspirated engine into each vehicle, instead of small-displacement turbo engines that have a relatively small window of optimal economy, Davis said.
Many jurisdictions, including Quebec, have set quotas for electric vehicles. Mazda is working with Toyota on battery-vehicle technologies, and says it will introduce mild hybrid technology by 2019 (the SkyActiv-X has an electric start/stop function); a battery-electric vehicle, possibly with a range extender, by 2020; and a plug-in hybrid by 2021.
Working on a “well-to-wheel” philosophy for carbon dioxide emissions, Mazda believes its gasoline engines can compete for environmental friendliness against dirtier methods of electricity production. It plans to offer electric vehicles only in areas with clean energy generation, or where they’re required by regulations, and intends to use combustion engines for the majority of its vehicles globally for many years.
In January 2018, Quebec enacted a zero-emission vehicle (ZEV) mandate. Of all vehicles an automaker sells in the province, 3.5 per cent must be ZEVs or purchased credit equivalents. ZEV-heavy automakers can sell their excess credits to those who don’t have enviro-rides in the stable, but the program’s too new for anyone to have extras, and Quebec charges a penalty of $5,000 per missing credit.
Since Quebec accounts for 30 per cent of Mazda Canada’s sales, the company said it has no choice but to pay up until it has an electric vehicle to offer. If its upcoming 2018 sales are similar to those of 2017, Mazda will owe the Quebec government $4.36 million this year under the mandate.