Q&A with Marmorini on the ECU changes
It has been a strong start to the season for the Toyota team with Jarno Trulli scoring eight points from the first three races. Toyota engine man Luca Marmorini talks of the demands placed on the team and driver this year with the introduction of a standard ECU.
How much work was involved in adapting to the standard ECU?
"A lot. We had to do many long test runs because the current engine was developed with a different ECU, made by Magneti Marelli. On top of this we had to cope with the other restrictions, on traction control, engine braking and so on. Even that change, if we had the freedom to adapt our own ECU, would have been significant but we had the standard ECU as well. We received documentation detailing the standard ECU systems but the tuning required testing not only on the dyno but also on the track. It was such a complex revision that there was not time to test everything, although we think we covered most of the uncertainties."
How significant are the differences between the previous ECU and the standard ECU?
"They are significant, not only from the engine point of view but also when it comes to gearbox and gearshift control. The seamless gearshift control is quite a delicate thing and you cannot afford any small mismatch or mistake. The team has done a great job with this but it has involved a lot of development.
People think there was no development at all because we have an engine development freeze and a standard ECU but it was actually a huge amount, comparable to developing a complete new engine. We had a lot of issues involving incompatibilities and had to learn to work within the right parameters."
Is the team still learning about the standard ECU?
"Definitely. If you think about what we did with our previous system, we were bringing some sort of software upgrade to each race, not only for performance but also to optimize strategy, so there is still a lot to learn to completely optimize the standard ECU. We can handle the new device and race with it but I can't imagine we have tested all the possible conditions, so, even though I believe our team did a great job, still there is a learning phase. I cannot assume all the problems are solved and we saw that in Australia when we had to change Timo's gearbox after practice due to an issue which originated from the wrong interpretation, on our side, of how to set the system."
If you look at the behavior of cars, what has changed?
If you do a back-to-back comparison from this year and last year it is very interesting. The pedal position of the driver last year was much more digital, so already in the middle of the corner it was flat, but the engine throttle was delayed. This year you see that there is a direct correspondence between the engine throttle and foot movement, so the driver has to do on his own what last year the ECU was doing. It's more difficult for him to go on the throttle, but of course we are helping by making the engine smoother. In the end the difference in lap time is minimal but there is a greater risk of a mistake. Over a race distance or with variable grip conditions there is more stress for the driver."
Do the drivers say engine braking is a bigger issue than the traction control?
"With the new regulations it was easy to focus initially only on the lack of traction control and underestimate how important the engine contribution was to effective braking, but we found this was quite significant to the driver. The driver has to be careful in variable grip conditions because the braking instability can mean him losing control of the car. Within the regulations we can use some engine maps to help a bit but it is very little compared to last year."
How much has the start procedure changed without launch control?
"It is dependent a lot more on driver skill. We can use a special launch map with less engine response at low throttle openings, so the driver can better control the wheelspin, but we have to use this map for 90 seconds so it cannot be too extreme, otherwise you risk spinning on the first lap. Full throttle means full throttle and you cannot chop it. If you make a throttle map that is very gentle initially and then very harsh, it would be risky on the first lap when the driver is fighting for position. The emphasis has to be not only on launch but also on first-lap performance - you don't want him spinning when he gets to a hairpin, for example. The regulation is designed so that you cannot help the driver too much with the special launch map." Source: Toyota