16 March 2021 · Tips N' Tricks

Engines uncovered. SKYACTIV-X explained

Q. WHO IS JAY CHEN?

DID YOU KNOW? Jay used to be the Engineering Editor of Sports Compact Car magazine.

A. Hi, my name’s Jay Chen. I’m the manager of the Powertrain Performance group here at Mazda North American Operations R&D. Basically I spend a lot of time driving around cars and making sure that they drive as a Mazda should.

Q. HOW DOES THE SKYACTIV-X ENGINE WORK?

DID YOU KNOW? A cylinder is the powerhouse of the engine, where fuel is burned and converted into energy that powers the car.

A. In your normal gasoline engine, imagine the cylinder inside of your engine. Let’s just say it’s a balloon. Every time the cylinder moves down, you’re pumping it full of air. It’s full of air, you add a sprinkle of gasoline in it, and then what you do is use a spark plug to light off this air and fuel mixture. What a lot of people don’t realise is that it takes time to burn from one side of the cylinder to the other side of the cylinder. So, it’s actually a slow burn kind of like the balloon flying away. In the Skyactiv-X case, you have the same cylinder filled with air and fuel. But it’s pumped to such a high pressure that when you introduce a spark, all the energy gets released in an instant. So, that same energy, because it’s released so much quicker, pushes harder down on the piston as a stroking down, and that makes the engine work harder, more power is extracted.   

DID YOU KNOW? Torque is a unit that measures force. It refers to the amount of work an engine can exert.

A. The Skyactiv-X engine really gives you the best of both worlds, compared to a normal gasoline engine and compared to even a diesel engine. Because we can release all of the energy so quickly inside of that balloon, we have the torque and the efficiency that is similar to a diesel engine. But because we’re using gasoline and a smaller engine, we’re also clean, efficient, and very responsive. So, for the customer basically that ends up being a very fuel-efficient car, still very clean and it still drives fun and responsive like a sports car with a gasoline engine instead.

Q. WHY HAS MAZDA ADDED THE SKYACTIV-X ENGINE TO ITS RANGE?

DID YOU KNOW? The Skyactiv-D engine is fuelled by diesel and the Skyactiv-G engine is fuelled by gasoline (petrol).

A. As we progressed, we wanted to make yet better engines that were more environmentally responsible. And so, we always knew that the path to a better internal combustion engine lay at the convergence between diesel technology and gasoline technology. And so, that’s how Skyactiv-X came about. Now, Skyactiv-X basically takes the good traits of gasoline engines along with the good traits of diesel engines and tries to eliminate all the bad traits like emissions, or slow delay or excess weight. 

Q. WHY WAS THIS TECHNOLOGY DEVELOPED?

DID YOU KNOW? Mazda Skyactiv-X engines can be used anywhere in the world.

A. So, Mazda’s perspective is that we wanted to build a technology that could be applied just as well in the cleanest parts of the world, let’s say Scandinavian countries that have clean energy, as well as it could be deployed and developed in let’s say South America, Thailand, Africa where potentially there may not be as many clean energy sources or charging stations available. So, the idea is to create a very clean and efficient internal combustion engine that can sell worldwide and through that reduce the overall impact on the environment because every vehicle is making a positive impact. 

Q. WHAT IS A MAZDA M HYBRID SYSTEM?

DID YOU KNOW? The Mazda M Hybrid system captures wasted energy and puts it to use.

A. In the Skyactiv-X we added this Mild Hybrid system. Now the system is basically this, it takes the energy of your vehicle as when you’re driving, you’re coming to a stop and as you’re coming to a stop typically you apply the brakes. And what that does is that it takes all the motion, momentum, kinetic energy of your car and just turns it into heat. That’s why your breaks get so hot. That’s wasted energy. Now, Mild Hybrid systems work differently. They can take the energy of your car slowing down and recover that energy and turning into electrical energy. So, just like this little flashlight I can take my mechanical energy, pump on it, then I can create electrical energy. Now, that electrical energy can be stored in a battery or capacitor and from there be used to restart your engine in the case of an engine stop at an intersection or to also help with the performance of your vehicle.  

Q. WHAT ARE THE BENEFITS OF A MAZDA M HYBRID SYSTEM WITH SKYACTIV-X?

DID YOU KNOW? The ‘M’ in Mazda’s M Hybrid system stands for Mild Hybrid.

A. A conventional hybrid vehicle as most of us know is not high on the list of fun to drive cars, but we’re able to preserve the same or similar fuel economy but still integrate all the Mazdaness, the fun to drive, the engagingness and the power into a vehicle. So, now again back to the best of both worlds. You have the economy; you have the fun to drive and you didn’t end up buying a vehicle with a powertrain that made you feel like you had to compromise.