Motor Trend’s Carlos Lago is back with the second installment of his quest to set the record for the fastest production hybrid at the Bonneville Salt Flats. In part 1 the guys took the first turbo hybrid for sale in the US, the Volkswagen Jetta hybrid, and prepped it for the Bonneville with racing and safety equipment. The 1.4 liter turbo engine and electric motor were tuned for a combined output of 300 horsepower at 30 pounds of boost. At the time, the Jetta broke the existing record but was ineligible due to the fact that it hadn’t hit production yet. This time around the car was legal and the team had made some tweaks including a lower ride height and smaller wheels to get even more top speed out of it. Check out the video to see how if they were able to officially get the speed record.
Motor Trend’s Johnny Lieberman gets an opportunity to tour AMG’s engine factory in Affalterbach, Germany and we get the pleasure of tagging along. He works with one of the AMG technicians to build one of the 5.5 liter twin turbo V8’s that powers the entire AMG line with the exception of the C63 AMG (the engineers thought the C63 was too light for the turbo engine’s torque so they stayed with the 6.2 liter naturally aspirated V8). The part that I found particularly interesting was the assembly and testing of the 2,000 psi direct injection fuel system. After everything is installed, they pressure test it for leaks with helium since it’s the smallest practical atom (hydrogen is smaller but more ridiculous to work with). The last thing they want is a bunch of high pressure fuel spraying all over the engine. This was a special opportunity for the Johnny unlike GM’s program where anybody can pay to assemble their own LS7 or LS9 for their Corvette or crate engine purposes. AMG actually decided not to put the engine Lieberman worked on into use. Right now it’s on a display stand where it can’t hurt anybody.
Motor Trend gives us an inside look at the Audi Quattro GmbH (the German equivalent of our LLC Limited Liability Company) Factory. This is where all of Audi’s top of the line sports models have been built since 1983. They are currently responsible for the RS3, RS4, RS5, RS6 and R8. Everything from the aluminum stamping to the painting and final assembly are done in-house.
Angus Mackenzie of Motor Trend is back with another truly excellent episode of Epic Drives. This time around he takes us to the garden of Europe, Sicily. While the active volcano and food culture there are unique attractions, it’s the roads that we’re interested in. The island of Sicily played host to the Targa Florio, a legendary historic race run along side the Mille Miglia and Le Mans. I’ll let Angus walk you through the history of the event, but it’s important to note that Porsche won the Targa Florio a record 11 times with lightweight mid-engine open top race cars. Their agility and durability allowed them to win over higher horsepower prototype cars. Mackenzie brings Porsche’s latest agile mid-engine roadster, the incredible all-new Boxster, to Sicily to drive the Targa Florio course once again.
If you’re a typical car guy, you probably don’t find driving hybrids very interesting. I don’t blame you. But just because the driving experience is usually sterile and unengaging shouldn’t undermine the fact that some serious engineering goes into making them work. This is a breakdown of the 2nd gen Prius transmission by an instructor at Weber State University where they work with Toyota on degree programs specifically having to do with the Hybrid Synergy Drive system.
The transmission is responsible for blending 3 different power input/outputs. The engine provides power to drive the car and to recharge the batteries, but it also requires power input to get started after it’s been turned off at stops. The two permanent magnet AC motors are referred to as Motor-Generators (MG1 and MG2) because they can easily be switched between propulsion and regeneration. MG1 is the smaller of the two electric motors and it acts as a starter, alternator and mainly as a generator fed by the engine power to recharge the battery pack. It’s also responsible for driving the car in reverse since that doesn’t require as much power. MG2 is the larger electric motor that is directly connected to the car’s wheels. It helps propel the car and is also responsible for regenerative braking. The engine and the two electric motors are tied together with a planetary gear set (ring gear, sun gear and planetary gear carrier). The video does an excellent job explaining how that works using the actual parts from the transmission.
The basic hybrid transmission architecture found in the Prius drive train was developed by a Japanese transmission company called Aisin and it is used by both Ford and Toyota. Does that mean that a Ford hybrid and a Toyota hybrid will get the same gas mileage since their hybrid systems have similar components and formats? Nope. Getting the best gas mileage is a complex puzzle of matching the power and torque requirements of the car with the efficiencies and operating points of the gas engine and electric motor. The gas engine is the most efficient at constant rpm and load like on highway driving. The electric motor provides better low end torque but it still has an optimum load and rpm. The planetary gear architecture basically allows an infinitely adjustable blend between the electric motor and the gas engine but you still need to know how to efficiently use it. When is the best time for the generator to use the engine power to recharge the battery pack? How low can the battery charge go before it needs to be recharged? Will using the electric motor’s low speed torque give the best overall gas mileage once the battery pack has been recharged? Should the gasoline be used to charge the battery or will more work be done if the same gas is burned to drive the wheels? It’s up to the software engineers to program the drive train controllers to figure out what the best combination of power input and output is for any situation the car sees. A good portion of the car’s price tag goes into the R&D and data crunching to figure these things out.
Check out Motor Trend’s latest episode of Head 2 Head. They take a look at the Toyota Prius V and the Ford C-Max hybrid. The guys do their usual excellent reviews of the cars, but the interesting part begins when the discussion turns to the gas mileage. Both cars didn’t get what the EPA rated them for and the Prius got the better real world mileage despite the C-Max having the better rating.
Even on a regular gas car, your mileage can vary massively based on where you drive the car (hilly terrain, higher elevations, traffic etc.) and how you drive it (pedal input smoothness, braking early, coasting etc.). The purpose of the EPA testing is not to tell you exactly what kind of mileage you will get, but to give you a standardized comparison between different cars. If you’re shopping for a hybrid, the emphasis really shouldn’t be on flat MPG figures as the Motor Trend guys have demonstrated. Your mileage will be based on how flexible your hybrid drive systems is. The car that will return the better gas mileage is the one that can consistently be the most efficient in a wide spectrum of driving conditions. It’s all in how the controls system (electric motor and gas engine blending) software is tuned.
The Motor Trend guys suspected that the Ford C-Max was tuned to rely on electric power up to a higher speed specifically to do better on the EPA test which ironically made it perform worse in real conditions. This result enforces story a few years ago about Prius drivers who would try to drive slower in an effort to keep the transmission from turning on the gas engine. This technique ended up giving the drivers worse gas mileage because it was completely depleting the battery pack. The system would then have to turn on the gas engine and run it at full recharge through the generator which reduced the overall mileage. The moral of the story is to do your research. What you want to look for is gas mileage consistency. What are other owners getting? Are people in different situations getting similar mileage or do the results vary a lot? My advice would be to put less emphasis on the EPA numbers and high score mileage numbers and try to find the hybrid that returns the least deviation in mileage numbers among a large number of owners. What you need to find is which automaker’s engineers did the best job programming the hybrid system to react to real world driving conditions. It’s a whole new ballgame for evaluating how well cars work. Now you have to look at how well the car is bolted together as well as how refined and effective its software package is.
