Alan J
12-09-2009, 10:25 PM
Though some might be interested in having a look inside a 3.0 ltr V10 Formula 1 engine.
JPEG 1 End Elev- some things to take note of, from top to bottom.
1. stepless servo operated inlet trumpets increase inlet tract length 50 mm at lower rpm. (Moveable trumpets are no longer permitted).
2. at high rpm injector is well above trumpet. One injector per cylinder operating at 130 Bar fuel pressure to improve atomization for better combustion, for more power and better fuel economy. (100 Bar is current maximum pressure allowed).
3. 43.5mm x 70mm oval throttle plate(equal to 58mm dia).
4. hollow cams with 31.5mm base circle dia. Inlet lifts 15.5mm and has seat duration of only 270 deg. Ex lifts 14.1mm and has just under 260 deg seat duration. Inlet lobe has very high acceleration and holds valve near full lift much longer than ex.
5. finger followers to save weight , improve valve action and more reliably compensate for valves set at compound angles (both in and ex inclined 12.5 deg and canted 3 deg).
6. air springs operating at 200 Bar
7. 2 x 40.4mm titanium inlet valve and 2 x 33.8mm inlet port, 2 x 33mm ceramic coated ex valve and 2 x 29mm ex port
8. very short skirt aluminium pistons (33.5mm) with single comp ring. Crown thickness carefully sculptured, varies from 7.5mm down to 4mm to reduce weight and maximize strength. Across the inlet side the flat squish area of the piston crown falls toward the center at 1 deg to reduce pumping loss and increase fuel burn. Even so engine needs 50+ deg advance at max power due to big chamber dia and short stroke, plus poor piston crown shape and valve pockets disrupting flame close to TDC.
9. narrow 3mm water jacket to increase water velocity, minimize water volume and weight. Minimal water cooling at top and bottom of bore; piston crown cooled by 2 oil jets.
10.forged titanium con rod 113mm long with pressure lubricated 19.5mm bushed little end (the rib up the rod is the oil feed. Except for the oil feed most of the beam is machined away, see photo)
11.vacuum cast extruded steel crank with 72 deg throws(block is 90 deg so engine fires 90-54-90-54 etc). 40mm crankpins, 48mm mains, tungsten heavy metal in balance weights.
12.sump divided into 5 compartments to reduce windage losses as pistons rise and fall.
13.oil pump on near left pressurises at 1 Bar at 4000rpm idle and 2 Bar max.
14.water pump far right pressurizes at 3.5 Bar
15.oil scavenge pumps on right, 12 of them draw on sump chambers, timing gear chambers and cam box area at a vacuum of 22in to reduce windage losses and improve ring seal, plus air/oil separator.
Fully dressed with Inconel exhaust and 4.5” clutch, engine weighs just under 100kg. 96mm bore x 41.4mm stroke, 12:1 comp ratio(for some circuits this was increased up to maximum of 13.2:1), 102 RON unleaded fuel.
Titanium con rod
carefully sculptured to reduce weight and maintain strength.. The rib up the middle is the oil feed to little end.
Inlet and Exhaust valve
both titanium with 5.5mm stem dia. Ceramic coating on ex valve head and stem where exposed to combustion flame to protect valve and keep combustion chamber cooler.
Malaysian GP stationary output
This is the power curve of an engine built for hot humid weather GP so has more conservative spec and mapping. This was a simulated stationary dyno pull without the artificial dyno lab atmosphere manipulated for the effects of altitude or car speed.
With this mapping the engine made a maximum of 806CV at 17,500rpm. (Maximum power spec engines made almost 90CV more than this spec). In the real world at say 300kph the engine makes 4.2% more power, about 840CV, due to ram air pressure in the air box. That’s assuming the usual short GP driver with non-disruptive aero do-dads on his helmet, so that’s the sort of power available down the main straights. A taller driver loses a bit and if he sticks to one helmet design the team may invest the big $ to get the lost 1-1.5% back.
In normal race mode this engine is run down to as low as 6000rpm in 1st gear, and down to 8000rpm in 2nd and 3rd to minimize wheelspin out of corners. In higher gears the engine is kept above 12,000rpm, to maintain 90% torque, or better.
Even though technically traction control is no longer permitted the throttles are fly-by-wire servo operated. The software provides techos the freedom to map the throttle opening rates to suit the circuit and driver. Aggressive throttlers like Hamilton and Webber are on the ragged edge of traction constantly so the throttle has to be manipulated to help tyre life and keep the car on the island, but these drivers do need a rush of power at times as that’s how they steer the car, so it’s a real science for the tech guys to get the throttle rate right. Smooth peddlers like Trulli and Button don’t like wild antics so the techos have an easier time of dialing in a smooth throttle opening rate. But even for them what the throttles are doing doesn’t look anything like what’s happening at the throttle pedal. Up to 75-80% throttle, each bank of throttles open at a different rate, with one bank of throttles trailing the other by up to 30%. So the left bank cylinders may be 50% open but the right bank only 20% open to help control traction. Then to keep engine wear equal for both banks the leading throttle swaps sides after each corner! As the race progresses the ECU then calculates how much work each bank has done (combination of throttle position, rpm, what gear selected and time) and then sets about balancing things up by the end of the race.
Perhaps the most technically challenging aspect of the F1 engine is keeping the valves, pistons and head separated at working rpm, and maintaining reasonably accurate valve open/close events. With a large bore and relatively small cylinder volume of only 299.8cc to achieve a 12:1-13.2:1 compression ratio is a feat in itself, but to maintain working clearance at 18,000rpm is a considerable engineering task not appreciated by the majority of engineers in lesser forms of race engine development. Even Moto GP designers, because of working with shorter, stiffer engines, do not face challenges of the same magnitude.
The issue is that at certain loads and rpm forces at work in the crankshaft, camshafts, cam drive gears and valvetrain in particular, plus con rods, pistons and block to a lesser extent, become harmonically excited to such a degree that contact between valves and pistons, and between pistons and head would be inevitable, even with quite large static working clearances that would possibly make achieving a compression ratio of only 10:1 unachievable. Consequently a large part of resources are expended not on finding power, but on dampening undesirable harmonics in the crank, cams and cam drive.
In fact this is among the most closely guarded of F1 development secrets. Minimise the harmonics, and then place those undampened or underdampened harmonics, out of phase with each other, results in more power via higher compression, less friction, better ring seal and more accurate valve motion, but also less fatiguing of components, and driver. Then it becomes feasible for certain parts to be made lighter. This has a chain reaction effect of allowing still other parts to be lighter or of less exotic materials, or requiring less expensive finishing or treatment processes and achieving better engine durability.
Cheers,
Alan
JPEG 1 End Elev- some things to take note of, from top to bottom.
1. stepless servo operated inlet trumpets increase inlet tract length 50 mm at lower rpm. (Moveable trumpets are no longer permitted).
2. at high rpm injector is well above trumpet. One injector per cylinder operating at 130 Bar fuel pressure to improve atomization for better combustion, for more power and better fuel economy. (100 Bar is current maximum pressure allowed).
3. 43.5mm x 70mm oval throttle plate(equal to 58mm dia).
4. hollow cams with 31.5mm base circle dia. Inlet lifts 15.5mm and has seat duration of only 270 deg. Ex lifts 14.1mm and has just under 260 deg seat duration. Inlet lobe has very high acceleration and holds valve near full lift much longer than ex.
5. finger followers to save weight , improve valve action and more reliably compensate for valves set at compound angles (both in and ex inclined 12.5 deg and canted 3 deg).
6. air springs operating at 200 Bar
7. 2 x 40.4mm titanium inlet valve and 2 x 33.8mm inlet port, 2 x 33mm ceramic coated ex valve and 2 x 29mm ex port
8. very short skirt aluminium pistons (33.5mm) with single comp ring. Crown thickness carefully sculptured, varies from 7.5mm down to 4mm to reduce weight and maximize strength. Across the inlet side the flat squish area of the piston crown falls toward the center at 1 deg to reduce pumping loss and increase fuel burn. Even so engine needs 50+ deg advance at max power due to big chamber dia and short stroke, plus poor piston crown shape and valve pockets disrupting flame close to TDC.
9. narrow 3mm water jacket to increase water velocity, minimize water volume and weight. Minimal water cooling at top and bottom of bore; piston crown cooled by 2 oil jets.
10.forged titanium con rod 113mm long with pressure lubricated 19.5mm bushed little end (the rib up the rod is the oil feed. Except for the oil feed most of the beam is machined away, see photo)
11.vacuum cast extruded steel crank with 72 deg throws(block is 90 deg so engine fires 90-54-90-54 etc). 40mm crankpins, 48mm mains, tungsten heavy metal in balance weights.
12.sump divided into 5 compartments to reduce windage losses as pistons rise and fall.
13.oil pump on near left pressurises at 1 Bar at 4000rpm idle and 2 Bar max.
14.water pump far right pressurizes at 3.5 Bar
15.oil scavenge pumps on right, 12 of them draw on sump chambers, timing gear chambers and cam box area at a vacuum of 22in to reduce windage losses and improve ring seal, plus air/oil separator.
Fully dressed with Inconel exhaust and 4.5” clutch, engine weighs just under 100kg. 96mm bore x 41.4mm stroke, 12:1 comp ratio(for some circuits this was increased up to maximum of 13.2:1), 102 RON unleaded fuel.
Titanium con rod
carefully sculptured to reduce weight and maintain strength.. The rib up the middle is the oil feed to little end.
Inlet and Exhaust valve
both titanium with 5.5mm stem dia. Ceramic coating on ex valve head and stem where exposed to combustion flame to protect valve and keep combustion chamber cooler.
Malaysian GP stationary output
This is the power curve of an engine built for hot humid weather GP so has more conservative spec and mapping. This was a simulated stationary dyno pull without the artificial dyno lab atmosphere manipulated for the effects of altitude or car speed.
With this mapping the engine made a maximum of 806CV at 17,500rpm. (Maximum power spec engines made almost 90CV more than this spec). In the real world at say 300kph the engine makes 4.2% more power, about 840CV, due to ram air pressure in the air box. That’s assuming the usual short GP driver with non-disruptive aero do-dads on his helmet, so that’s the sort of power available down the main straights. A taller driver loses a bit and if he sticks to one helmet design the team may invest the big $ to get the lost 1-1.5% back.
In normal race mode this engine is run down to as low as 6000rpm in 1st gear, and down to 8000rpm in 2nd and 3rd to minimize wheelspin out of corners. In higher gears the engine is kept above 12,000rpm, to maintain 90% torque, or better.
Even though technically traction control is no longer permitted the throttles are fly-by-wire servo operated. The software provides techos the freedom to map the throttle opening rates to suit the circuit and driver. Aggressive throttlers like Hamilton and Webber are on the ragged edge of traction constantly so the throttle has to be manipulated to help tyre life and keep the car on the island, but these drivers do need a rush of power at times as that’s how they steer the car, so it’s a real science for the tech guys to get the throttle rate right. Smooth peddlers like Trulli and Button don’t like wild antics so the techos have an easier time of dialing in a smooth throttle opening rate. But even for them what the throttles are doing doesn’t look anything like what’s happening at the throttle pedal. Up to 75-80% throttle, each bank of throttles open at a different rate, with one bank of throttles trailing the other by up to 30%. So the left bank cylinders may be 50% open but the right bank only 20% open to help control traction. Then to keep engine wear equal for both banks the leading throttle swaps sides after each corner! As the race progresses the ECU then calculates how much work each bank has done (combination of throttle position, rpm, what gear selected and time) and then sets about balancing things up by the end of the race.
Perhaps the most technically challenging aspect of the F1 engine is keeping the valves, pistons and head separated at working rpm, and maintaining reasonably accurate valve open/close events. With a large bore and relatively small cylinder volume of only 299.8cc to achieve a 12:1-13.2:1 compression ratio is a feat in itself, but to maintain working clearance at 18,000rpm is a considerable engineering task not appreciated by the majority of engineers in lesser forms of race engine development. Even Moto GP designers, because of working with shorter, stiffer engines, do not face challenges of the same magnitude.
The issue is that at certain loads and rpm forces at work in the crankshaft, camshafts, cam drive gears and valvetrain in particular, plus con rods, pistons and block to a lesser extent, become harmonically excited to such a degree that contact between valves and pistons, and between pistons and head would be inevitable, even with quite large static working clearances that would possibly make achieving a compression ratio of only 10:1 unachievable. Consequently a large part of resources are expended not on finding power, but on dampening undesirable harmonics in the crank, cams and cam drive.
In fact this is among the most closely guarded of F1 development secrets. Minimise the harmonics, and then place those undampened or underdampened harmonics, out of phase with each other, results in more power via higher compression, less friction, better ring seal and more accurate valve motion, but also less fatiguing of components, and driver. Then it becomes feasible for certain parts to be made lighter. This has a chain reaction effect of allowing still other parts to be lighter or of less exotic materials, or requiring less expensive finishing or treatment processes and achieving better engine durability.
Cheers,
Alan