The Masters Who Gave Life to Nissan ARIYA #05.1

Engineering Monster will deliver the essence of Nissan’s technology by interviewing the engineers who participated in the development of “Nissan ARIYA,” which symbolizes “Nissan Intelligent Mobility.” We will also deliver the behind-the-scenes of the development that created innovative technology and the DNA of Nissan that breathes in “Nissan ARIYA” as original content.

This time, Ryozo Hiraku, the expert leader who created the innovative advanced technology e-4ORCE, which is installed in Nissan Ariya will talk about e-4ORCE technology as a two-part article.

I interfere with Nissan ARIYA project even though it’s not my responsibility. I am being resented by the internal engineers.

After joining Nissan in 1990, I worked as a drivetrain engineer and was involved in the development of CVT. At that time, 4-speed AT was still mainstream, and CVT was not a major presence. Various transmission possibilities, such as multi-speed AT, CVT, and DCT, were being explored by automotive manufacturers for the future, and our company was searching for a strategy to focus on developing one type of transmission.

At that time, Nissan believed that if we were to compete with other companies using only one type, CVT was the only choice. CVT was initially considered for small cars, but we thought that eventually, CVT would be necessary for larger displacement vehicles, which we struggled with back then. While other companies were advancing the multi-speed AT, we thoroughly considered how to create a CVT that could handle large displacement vehicles.

CVT we introduced to the world was first installed in Murano, which was launched in North America in 2002 and later introduced in Japan. I am resented by internal engineers because I often interfere with other people's projects, even though it's not my responsibility (laughs). This may also be related to my experience of working in Ginza's headquarters, where I was responsible for business planning and other tasks, which is unusual for Nissan engineers who typically focus on technical roles.

In an electric vehicle that operates with very fast response speed, the order of controlling the car differs significantly from a gasoline vehicle.

Although I was not in charge of the development of Nissan ARIYA, I was always giving my input on the development of motor-driven four-wheel drive. One day, an executive asked me, "What should we do?" I expressed my thoughts and then began to launch a development team for motor-driven four-wheel control. This was the start of e-4ORCE as it is today.

I have always believed that the way we build cars changes when they are driven by motors. Cars control six movements: “front and rear”, “left and right”, “up and down”, “roll,” “pitch”, and "yaw" during driving. For example, the powertrain and brakes are responsible for the front and rear movements, while steering is responsible for the left and right movements. It is the balance of these movements that determines the driving feel of the car.

The response speed to control these movements is fastest with electricity, followed by hydraulics and then air. The engine utilizes air response. Even if you are not familiar with physics, anyone who has driven a car should understand that it is not possible to eliminate the torque generated when pressing the accelerator pedal 0.1 seconds later. Conventional gasoline cars control the power and torque of the engine using hydraulics such as brakes and suspension, and finally add electronic control to control the overall movement.

EVs have the fastest response speed as they are powered by electric motors. Therefore, the order of controlling the car in EVs differs significantly from gasoline cars. What was previously considered normal to be done with brakes and steering now has an area where it can be done faster and more precisely with motors. The challenge lies in how far we can push this area. This became the origin of e-4ORCE development.

Is it okay for Nissan, the leader in EVs, to be satisfied with the same technology as other companies?

When it comes to 4WD EVs, many people may associate them with high-powered motors installed in the front and rear. However, this technology has already been commercialized by other companies. Nissan, as a pioneer in EVs and aiming for leadership, can they proudly release a car with the same technology as other companies and make customers happy? I don’t think so. e-4ORCE is a technology developed with that belief as the driving force. Our goal was to remove all areas of control, such as suspension, brakes, steering, and powertrain, that were handled by hydraulic systems and reconstruct them. In November 2019, we completed a prototype and held a test drive event for executives, proving that “by reconstructing the role of control using two motors, we can achieve this level of performance”. The executives who got off the prototype were all amazed, and e-4ORCE was chosen to be adopted in the first place by Nissan ARIYA.

The article is from its original version released on 10 November 2020.