Professor Ricardo Martinez-Botas talks about the road to low carbon vehicles

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Professor Ricardo Martinez-Botas

Professor Ricardo Martinez-Botas

There is more than just one path to reducing harmful emissions, says the Professor, who leads the Turbochargers research group at Imperial.

This year, the UK government announced its commitment to ban all new gasoline and diesel vehicles from 2040, following a similar announcement from other nations. In practice, the change towards to a low carbon, sustainable world is not without pitfalls, as evidenced by the 2015 Volkswagen scandal, when the German automaker was found to be cheating emissions tests.

Professor Ricardo-Martinez Botas was the independent expert who oversaw the Vehicle Emissions Testing Programme initiated by the British government in the aftermath of the scandal. The Professor believes internal combustion engines will not be completely replaced by electric vehicles in the medium term; instead, they will evolve to be configured differently. The transition will be slower than most people believe, he says- so it is paramount that action is taken to ensure low emission vehicles are seen as the norm on our roads:

“The status of emissions in our cities is unacceptable. In that context, I see electrification as the only way forward. However, if we went purely electric for all modes of transport, the energy demand would be so huge, it’s hard to believe we could deliver it. It is also a challenge to make the electric vehicles affordable and produced to the magnitude needed. I’m a great believer in low carbon and low emission vehicle technology, but the path towards this goal is not exclusively via electric vehicles. I think there is a place for EVs, there is a place for hybrids with highly optimised internal combustion engines, and in heavy duty there is a place for pure internal combustion engines running on sustainable fuels. We will see the end of direct drive internal combustion engines, but not the death of the internal combustion engine; they will change to be embedded in an highly electrified mobility platform. In our cities, Diesels in cars will be the first to go, followed by gasoline engines: it’s unlikely we will allow any form of combustion. This is quite a big change already. “

How did you become a part of the UK government investigation into the Volkswagen scandal, and what did you find out?

I’ve been part of the Science Advisory Council for the Department for Transport for the last three years. The government was looking to assess whether or not other vehicle manufacturers were manipulating their emission vehicle systems. For this purpose, a large testing program was set up independent of the manufacturers of the vehicles. There was also a need to find out the real world emission levels of our vehicles from the current UK fleet composition. I was appointed to oversee this process.   

Thirty-seven vehicles were tested comprehensively, and the findings were reported in a public domain document, which was presented in Parliament in 2016. There was no evidence that any of the other manufacturers we tested tried to cheat our vehicle emission standards, but we found that the level of NOx emissions on our roads is far higher than what one would have expected, on average five times more, and in some cases ten times more.

Does this mean the current emission tests are not adequate?

We will see the end of direct drive internal combustion engines, but not the death of the internal combustion engine; they will change to be embedded in an highly electrified mobility platform.

– Professor Ricardo Martinez-Botas

The current tests are not adequate, and they’re changing. New testing procedures (WLTP) have been introduced this year by the European Union. They include a more realistic version of the previous test on the dynamometer rolling road, but also a test on the road, for the first time. That is a major change that will hopefully reduce real world emissions. Changing the test cycle was already planned, but it’s been accelerated due to the Volkswagen scandal. It’s taken eight years to get agreement, which shows that regulations are not moving as fast as we need.

How does your research help achieve low carbon engines?

I work on increasing engine efficiency, but I look at one specific part of this big problem. The exhaust of an engine has a high level of energy content, so if we put a turbocharger in the exhaust, we can recover energy, couple the turbine to a compressor, and get high-pressure air into the cylinder. This way, one can either obtain more output power, or maintain the power and make the engine smaller- which means fewer moving parts, less friction, and therefore better overall efficiency. That is one of the paths to low carbon vehicles. My area of research looks into optimising the components on the both the turbine and the compressor side. There are many ways of boosting, one of them is electrifying the turbocharger, what we call hybridising the air system, and a number of projects in my group are exploring this avenue at this moment.

Why did you choose this research area?

I come from the aero-engine area. During my PhD at Oxford, I worked on gas turbine propulsion and the aerodynamics of blades. When I arrived at Imperial College I had the opportunity to take on a new area, small turbine aerodynamics. I thought it was very exciting, because it was a less understood area where I could have greater impact.

Ricardo Martinez-Botas

What innovations has your work produced?

We have developed a new concept, active flow control of turbochargers. Turbochargers are in their nature very static, but we have introduced a dynamic component that adapts to the engine environment. We have also patented improvements to the compressor, and we’ve developed a very high-performance turbine, that can scavenge-recover energy from the exhaust at an efficiency of around 70%, which is unprecedented. Out of five ideas we have put work into, all of which have been patented, one is in production, and four others are in the process of being commercialised. These concepts contribute to the overall goals of fuel economy and CO2 reduction.

We’re currently working on a project to increase the efficiency of the compressor, and deliver an improvement of the current components. The objective is a significant improvement in compressor efficiency. We have another project trying to understand the flow inside a turbine, an old problem that we’ve been dealing with for years. Finally, we’re developing what we call a turbine expander for energy recovery, and that’s a topic that will keep growing, I suspect. Applications for these innovations include road vehicles, but also heavy-duty vehicles, off-road machinery, mining equipment, building and construction equipment. You could say, anything that has an internal combustion engine!

What motivates you in your work? What do you enjoy most about it, and what kind of impact are you hoping to achieve?

I am highly motivated by training people, increasing their knowledge and thus producing high quality scientists and engineers. I am very passionate about teaching, and lecturing is without doubt, one of the things I have greatest pleasure from. The ability to transmit knowledge is fantastic. I seek to ensure that my work achieves a legacy: people, knowledge, publications and books.

An exciting impact is, of course, reducing the CO2 footprint of engines. Then, if our research leads to better understanding with impact, that is enough for me to be motivated. Finally, if I can see that understanding lead into a product that is manufactured, that is the ultimate impact for me. Through our collaboration with our industrial sponsors, we have one of our ideas in production since October last year, and several million units have been produced. It’s very exciting to see the ideas of my group being used in the marketplace!

What brought you to the Department of Mechanical Engineering?

Coming to Imperial as an undergraduate student was just fantastic, I must say. I had great fun, worked hard, but also a lot of intellectual excitement.

– Professor Ricardo Martinez-Botas

I spent two summers in the 1980s working as a UROP student in the Mechanical Engineering department here, with the late Professor Besant, and I got to know his group. Seven years later, when this job came up, they called me. You never know how something you do at some point can lead to something else! As a consequence, I always take students on internships, because I think the same that happened to me can happen to them. I had four students doing UROP with me this summer.

Why did you want to become an engineer?

When I was a teenager and I had to choose, I thought I could either be a historian or an engineer. The former became my hobby and the latter became my profession. I chose, but equally, I could have chosen the other path. Coming to Imperial as an undergraduate student [in Aeronautics] was just fantastic, I must say. I had great fun, worked hard, but also a lot of intellectual excitement. And I think that confirmed that I had chosen right.

 

Reporter

Nadia Barbu

Nadia Barbu
Department of Mechanical Engineering