The third area of innovation is the powertrain. Here Lexus worked both in-house to find solutions and went outside the company to a partner in previous engine endeavors. In-house solutions were found to keep the balance of the car at 52% front and 48% rear and to get a maximum amount of power from the front-mounted engine to the rear-drive wheels.
Starting at the back is a transaxle unit that contains differential, transmission and clutch. The six-speed transmission is actually a manual transmission with electronic and hydraulic controls. In addition to reducing total mass of the clutch by using a single-disc clutch (rather than a multi-disc unit), Lexus engineers also reduced rotating mass by reducing the diameter of the clutch.
The transaxle is joined to the engine via a toque tube that is an industry first because it is offset somewhat. To keep the engine mounted as low as possible, Lexus engineers utilized an industry-first offset gear on the crankshaft rather than a direct drive as others have done.
At the front of all this is a Yamaha-designed, Lexus-built V10 that is only utilized in the LFA. Each aluminum engine is hand-assembled with titanium rods and valves along with aluminum pistons. Yamaha is noted for small bore engine expertise, particularly in the motorcycle area with their R1 motorcycle. The R1 utilizes four valves per cylinder and has a bore smaller than that of the V10. R1 output is roughly 150 hp out of a one-litre engine and the LFA puts out 552 hp out of 4.8 litres. In essence, the LFA puts out less power per litre than what normal Yamaha engines do (R1 is 150 hp/litre and the 4.8 is 115 hp/litre).
Other interesting features (not quite technological breakthroughs) include “chimneys” that duct heat from the exhaust manifolds up and away from the engine. Air flow management has also been taken to new lengths by moving the radiators to the rear fenders. Air flow here maximizes cooling while allowing for controlled turbulence at the rear of the car which adds down force. It also allows for better control of incoming air and for better cooling of the six-piston front calipers and carbon/ceramic brake rotors (four-piston calipers in the rear)
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| Photo: Lexus |
Starting at the back is a transaxle unit that contains differential, transmission and clutch. The six-speed transmission is actually a manual transmission with electronic and hydraulic controls. In addition to reducing total mass of the clutch by using a single-disc clutch (rather than a multi-disc unit), Lexus engineers also reduced rotating mass by reducing the diameter of the clutch.
The transaxle is joined to the engine via a toque tube that is an industry first because it is offset somewhat. To keep the engine mounted as low as possible, Lexus engineers utilized an industry-first offset gear on the crankshaft rather than a direct drive as others have done.
At the front of all this is a Yamaha-designed, Lexus-built V10 that is only utilized in the LFA. Each aluminum engine is hand-assembled with titanium rods and valves along with aluminum pistons. Yamaha is noted for small bore engine expertise, particularly in the motorcycle area with their R1 motorcycle. The R1 utilizes four valves per cylinder and has a bore smaller than that of the V10. R1 output is roughly 150 hp out of a one-litre engine and the LFA puts out 552 hp out of 4.8 litres. In essence, the LFA puts out less power per litre than what normal Yamaha engines do (R1 is 150 hp/litre and the 4.8 is 115 hp/litre).
Other interesting features (not quite technological breakthroughs) include “chimneys” that duct heat from the exhaust manifolds up and away from the engine. Air flow management has also been taken to new lengths by moving the radiators to the rear fenders. Air flow here maximizes cooling while allowing for controlled turbulence at the rear of the car which adds down force. It also allows for better control of incoming air and for better cooling of the six-piston front calipers and carbon/ceramic brake rotors (four-piston calipers in the rear)
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| Photo: Lexus |