Over the past three seasons we have become used to the Kinetic Energy Recovery System, allowing drivers the choice of when they used the additional 6.7 seconds of power from the 60kW (80.5 bhp) motor generator unit. We have seen some drivers using this boost strategically to fend off attempted DRS passes, or to successfully pass drivers in unexpected places.
For next season this changes dramatically. There are two motor generator units, a 120kW (161 bhp) Motor Generator Unit – Kinetic (MGU-K) much the same as this seasons KERS unit, but double the power, and a Motor Generator Unit – Heat (MGU-H). This latter unit is unspecified in term of power and is connected to the single turbo charger (pressure charging system). The rules specify a single compressor, and so this is likely to be large to give maximum boost. Unfortunately this comes with a penalty of turbo lag. While the Rally Cars solved this problem in the 1990’s by pumping unburned fuel into the exhaust and igniting it to keep the turbo spinning, this solution is not going to work for F1 with a 100kg of fuel as the upper limit for a race distance. Instead the MGU-H will have to reduce the turbo lag.
Appendix 3 of the FIA F1 2014 Technical Regulations has a nice diagram of the energy flows allowed in the new ERS for next season:
So the Energy Store has a maximum useable capacity of 4MJ (ten times that allowed this year), so on first glance it looks like the boost available from the ERS will be available for five times as long as this year (the motor is twice as powerful so consumes the available energy at double the rate), that would give a 161bhp boost for 33.3 seconds. Unfortunately the situation is slightly more complicated than that, as while 4MJ of energy can pass from the energy store to the MGU-K each lap, only 2MJ of energy can pass the other way. Could this open the door to even more strategic deployment of the ERS as drivers save up the available boost for a lap and then overtake an unsuspecting rival the next? It is possible, and certainly it is one interpretation of the rules. However looking at the allowable energy flows on the diagram this doesn’t take into account the MGU-H, which has unlimited flow both to and from the Energy Store, and the MGU-K.
I think it should be possible to design the ERS where It is effectively always on, so there is no need for a separate button on the steering wheel. This is how I think it should work.
- At the start of the race, the Energy Store is fully charged, as the revs rise waiting for the lights to go out, the MGU-H spins the turbo to eliminate any turbo lag.
- As soon as the car starts moving and it is no longer traction limited, the MGU-K would also come into play.
- Once the throttle is open fully, and the turbo is up to speed, the MHU-H would feed its power through to the MGU-K, with any excess going to the Energy Store
- As the car brakes for a corner, the MGU-K is used to charge the Energy Store, and to keep the Turbo spinning (to prevent any noticeable turbo lag when the driver gets back on the throttle)
Mid corner, with the driver on part throttle we are back to the situation at diagram 1 again, and so the cycle repeats. With the energy flow between the MGU-H and MGU-K unlimited in either direction, as long as the turbo is big enough to supply the 120kW needed to drive the MGU-K, there should be no need for a button on the steering wheel.
If this proves to be the case, will you feel robbed of a ‘push to pass’ system, or do you consider it a more efficient way of generating the power an F1 car needs to race than the current 2.4 litre V8s?