Inside Mazda’s New Two-Turbo, Four-Cylinder Diesel Engine

40 Mpg Daily Driver Coming For 2014 Mazda Skyactiv Front Three Quarter

When we first discovered Mazda was bringing its two-stage turbocharged diesel to North America, we celebrated. We think you’re going to, too. According to Mazda, sometime in 2014 you’ll be able to buy a Mazda6 (family sedan), which gets more than 40 mpg on the highway. Furthermore, it’ll require no expensive NOx aftertreatment and no urea—as it breezes past strict Tier 2 Bin5 emissions tests. Mazda is so confident in the engine’s ability to meet these strict emissions requirements, it’s even going to offer the Mazda6 with a manual transmission.

40 Mpg Daily Driver Coming For 2014 Mazda Skyactivs Driving

Mazda invited us to Vancouver, Canada, to testdrive automatic- and manual transmission-equipped versions of its upcoming ’14 Skyactiv-D Mazda6. The vehicles we drove were test mules, so the fit and finish wasn’t quite like a new car—but we didn’t mind. It did take us a little time to get used to the righthand drive steering wheel, which some of the vehicles were equipped with.

Mazda invited us to Vancouver, Canada, to testdrive automatic- and manual transmission-equ

Skyactiv-D: Philosophy and Technology
Some in the auto industry would like you to think the internal combustion engines we have today are about the best we can do in terms of efficiency, emissions, and fuel economy. Some want to throw all these engines away in favor of expensive, non-renewable battery systems that still lack an infrastructure. Mazda’s Skyactiv-D (the D stands for diesel) philosophy bucks this trend and takes the opposite approach by finding improvements in all areas of the modern automobile.

The Mazda suite of Skyactiv-D technologies includes a lighter and stronger body construction, suspension geometry improvements, efficient transmissions, and, of course, cleaner and stronger diesel power. By putting all this together in one vehicle, the consumer benefits. We get a reasonably priced vehicle that’s a blast to drive, our pocketbook doesn’t get too skinny, and our cars help keep the sky clear and healthy for future generations.

Vehicle Specifications
Model: ’14 Mazda6
Engine: 2.0L Skyactiv-D
Type: All-aluminum inline four-cylinder with chaindriven camshafts and an internal balance shaft
Bore: 3.38 inches
Stroke: 3.7 inches
Compression ratio: 14:1
Weight: 308 pounds (with accessories)
Fuel injection: Common-rail with piezo injectors
Fuel requirement: Diesel, B5
Valvetrain: 16-valve dual overhead cam
Horsepower: 170 hp
Torque: 310 lb-ft
Aftertreatment: Engine-mounted diesel oxidation catalyst (DOC) and diesel particulate filter (DPF)
Transmission: Skyactiv-MT six-speed manual and Skyactiv-Drive six-speed automatic
Fuel economy: 20 percent improvement as compared to Mazda’s current 2.2L diesel
Steering: Electric power assist steering (EPAS)

The 2.0L Skyactiv-D’s increased torque was easily noticed when we compared it to Mazda’s outgoing 2.2L diesel with a single variable-geometry turbo. We were amazed we could spin the new 2.0L diesel engine to 5,600 rpm during our testdrive.
The 2.0L Skyactiv-D’s increased torque was easily noticed when we compared it to Mazda’s o
The Skyactiv-D diesel’s cylinder head, block, and bedplate are all made from aluminum alloy. The intake has a throttle valve, and there are both low- and high-temperature EGR loops.
The Skyactiv-D diesel’s cylinder head, block, and bedplate are all made from aluminum allo
The DOC and DPF fit in the same engine compartment. There are two turbos (a small and big turbo) that are staged to create up to 37 psi of boost pressure. They both blow intake air through an air-to-water charge-air cooler. One of the turbochargers bolts right to the head. This eliminates the need for an exhaust manifold and reduces wasted heat.
The DOC and DPF fit in the same engine compartment. There are two turbos (a small and big

Those familiar with diesel performance may be aware of the advantages of a low-compression engine. Mazda discovered that by lowering the engine’s compression ratio, it could improve the fuel and air mixture and achieve a more complete combustion event. Since the burn takes longer with less pressure, Mazda’s engine calibrators are finished injecting fuel by the time the piston reaches top dead center. This creates a bigger expansion ratio than would occur in a conventional diesel engine and allows more work to be done on the piston. This is one of the ways Mazda is cleaning up diesel emissions in the cylinder.
Those familiar with diesel performance may be aware of the advantages of a low-compression
The 2.0L engine’s chaindriven oil pump features a conventional design, although its electronic bypass valve is anything but normal. High- and low-pressure oil is directed to the engine when conditions dictate. This valve saves fuel.
The 2.0L engine’s chaindriven oil pump features a conventional design, although its electr
The oil pump also supplies pressure to the variable-valve-lift camshaft system. Mazda also uses a variable-valve-lift system on four of the exhaust valves. This hardware allows hot exhaust to be routed back into the cylinder, which helps warm the engine during cold starts. This, combined with the glow plugs and Mazda’s injection strategies, solves the problem of starting a cold, low-compression diesel engine.
The oil pump also supplies pressure to the variable-valve-lift camshaft system. Mazda also

How Lighter Parts Improve Power and Save Fuel

The current Mazda 2.2L diesel’s crankshaft is made from forged steel, but it’s built like a tank.
The current Mazda 2.2L diesel’s crankshaft is made from forged steel, but it’s built like
The new Skyactiv-D 2.0L’s crankshaft is also forged—but it’s 9.9 pounds lighter than the 2.2L’s.
The new Skyactiv-D 2.0L’s crankshaft is also forged—but it’s 9.9 pounds lighter than the 2
The Mazda 2.2L’s connecting rods look like mini Power Stroke rods.

The four Skyactiv-D 2.0L forged connecting rods weigh a total of 1½ pounds less than the 2.2L engine’s rods.
The four Skyactiv-D 2.0L forged connecting rods weigh a total of 1½ pounds less than the 2
The original pistons used a small-diameter piston bowl.
The four Skyactiv-D 2.0L’s pistons weigh almost 2 pounds less than the 2.2L pistons they replace.
The four Skyactiv-D 2.0L’s pistons weigh almost 2 pounds less than the 2.2L pistons they r