A New Engine Concept for a practical Malibu Hybrid

[dwightlooi]

The idea here is not to produce the ultimate gas savings or the highest performance. Instead it is a Mild Hybrid which combines amicable fuel consumption with lively driving characteristics. The system is avoids the weight and cost burden of a big battery, while benefiting from an efficient asymmetric combustion cycle. The price premium will be in the order of $1000 over a turbo Malibu, while the driving experience -- especially in daily driving regimes in the idle to 4000 rpm range -- will be similar to a 3 liter V6.

Ecotec XFE

• 2.4 liter DOHC-16v Inline-4 Miller Cycle Engine w/ Intake & Exhaust VVT

• Turbocharged and Intercooled; Honeywell-Garrett MGT1548 Turbocharger @ 10.3 psi

• 88 mm (bore) x 98 mm (stroke); Bore Centers 96 mm

• Static Displacement 2384 cc

• Effective Displacement 1788 cc

• Effective Compression 10.2 : 1

• Direct Gasoline Injection

• Dual Balance Shafts

• BAS II Mild Hybrid system with 115.2V Lithium Ion Electric System (0.5 kWh)

• 175 bhp @ 4600 rpm (ICE) + 15 bhp @ 2800 rpm (Electric)

• 200 lb-ft @ 1600 ~ 4600 rpm (ICE) + 79 lb-ft @ 0 rpm (Electric)

• Redline @ 4600 rpm / Rev limit @ 5000 rpm

• 87 Octane Required

• Applications: Chevrolet Malibu (Gen VIII) Hybrid; Buick Regal eAssist, Lacrosse eAssist

• Transmission: Hydramatic 6T45 6-speed Automatic w /Idle Stop Control

Axle Ratio 2.89 : 1

Gear Ratio (Maximum Speed in Gear)

1st : 4.584 (25mph @ 5000 rpm)

2nd : 2.964 (41mph @ 5000 rpm)

3rd : 1.912 (66mph @ 5000 rpm)

4th : 1.446 (86mph @ 5000 rpm)

5th : 1.000 (122mph @ 5000 rpm)

6th : 0.746 (130mph @ 3908 rpm) *

* Governed; Maximum Speed rating of H-rated Goodyear Assurance Fuelmax tires

Cruising RPM

1954 rpm @ 65 mph

2405 rpm @ 80 mph

Est. Fuel Economy

28 mpg (City) / 40 mpg (Hwy)

Edited April 12, 2011 by dwightlooi

[Paolino]

Yes and No. I think it's a great idea, the turbo will add power down low and give the car a little boost so it doesn't feel so heavy, however, the numbers need to aim a little higher--the Fusion Hybrid is rated at 40 city, 36 hwy... so although yours beats it on highway by a few, it gets SLAMMED in the city dept. What needs to be kept in mind is that the Malibu debuts in 2013... by then we'll either have a new Fusion or be close to a new one (and other new hybrids from other manufacturers like the Camry and Altima), and their numbers will have probably increased as well.

[loki]

i don't think it's bad... but the redline popped out at me as something "sporty drivers" will laugh at world wide.

the gains over the one now are ~20%, yes?

[Drew Dowdell]

So it would have ~270 lb-ft at 1600 RPM?

[dwightlooi]

So it would have ~270 lb-ft at 1600 RPM?

Not quite... but it is substantial.

The BAS is 79 lb-ft at 0 rpm. But by 2800 rpm it has dropped to 28 lb-ft, which corresponds to 15 hp. Assuming that the decrease is linear, at 1600 rpm when the ICE hits its torque plateau of 200 lb-ft, the BAS is capable of about 50 lb-ft from the electric motor for a total of about 250 lb-ft. In reality though, the assist output will probably be dialed back to keep the total torque output to about 232 lb-ft -- the maximum rating of the 6T45 automatic transmission. The motor will make 50 lb-ft only when the ICE is not at Wide Open Throttle, which is when the engine needs the most help anyway.

BTW, the 5000 rpm red line is there because a SMALL turbo like the MGT15 will run out of breathe anyway and going to the 2.4's 7000 rpm theoretical redline will make a lot of noise and nothing else. The car will be faster if you shift at ~5000 rpm anyway. However a small turbo also spools faster and lets you hit 200 lb-ft at a rock bottom 1600 rpm as well as minimize lag in those 2000~4000 rpm freeway passing scenarios. This is also where the motor is at its 15bhp peak rating which all plays together well.

Anyway, the whole idea is that where people do most of their driving -- be it pulling away from the light, passing on the freeway or putting pedal to the floor, the engine pulls like a 3.0~3.5 liter V6 up to about 4000 rpm or so. The engine also beats a Cruze automatic on fuel economy while incurring a the minimum Hybrid premium. Also, unlike more elaborate Hybrids, this one actually makes economic sense. At a 8mpg advantage over a 4-cylinder Malibu, the premium of $1000 pays off after about 3.5 years at $4 a gallon instead of the 11~13 years for most Hybrids. So, you don't have to drink the Global Warming coolaid to justify buying one.

Edited April 13, 2011 by dwightlooi

[smk4565]

Drop a diesel in that sucker.

[CanadianBacon94]

Drop a diesel in that sucker.

well the idea i believe is best return for investment, so they want to make it as simple as possible,

if diesels are more mainstream and the price difference was reduced i could see this as a diesel would improve the mileage even more