Smart Car Conversion

SmartHEV: Depending on what my final design entails, this will mean either a converted:

  1. 2006 Smart ForTwo Passion Coupe Hybird Electric Vehicle

or

  1. 2006 Smart ForTwo Passion Coupe Hydraulic Energy Vehicle

…stay tuned to find out which design wins :-D

Why?

The gasoline version is too noisy 8-)

Well, more seriously:

  1. I purchased this vehicle in November of 2006, and an original goal was to start planning an EV conversion when it was 5 years old.
  2. The jerky transmission is really annoying…really, really, really annoying.
  3. Current (October 2012) vehicle milage is 102,000km.
  4. This vehicle's 699cc engine needs to be rebuilt at around 100,000km. The clutch and transmission will also require specialized (Mercedes dealership) service as well. Costs rise quickly here; I can either discard the vehicle, repair/rebuild the engine & drivetrain, or replace things…
  5. Projected rebuild costs total $5,500:
    1. $1,000 for cost of parts + shipping from the UK (known cost)
    2. $2,500 in billable shop labor (projected costs)
    3. $2,000+ to resolve silly “surprises” that typically emerge during during major maintenance (hidden costs)

Design Goals

GOAL STATUS
Maximum cruising speed: 75 MPH designing
Maximum speed on 5% grade: 50 MPH designing: need 35HP@0.35Cd, 30HP@0.17Cd
Minimum range: 100 miles designing
Minimum Acceleration: 0-60MH in 16 seconds (existing gas car's performance) designing
Retain luxuries: AC/Heat, power windows, locks, steering & brakes designing
Eliminate jerky gearbox shifting totally eliminating gearbox
Simplify vehicle electronics that easy when you're gutting the existing powerplant ;-)

Maximum climbing speed is based on the desire to climb a steep section of Hwy26 leaving downtown Portland Oregon, at the posted 50MPH; estimated elevation grade is 5%. Section is ~2 miles long.

Public Discussions

Performance Expectations

I fully-intend to fix the air resistance issues, which promises to cut the Cd in half, after converting the vehicle; I'd like the ability to accurately measure streamlining results.

Excellent online calculators

Assuming

Vehicle weight 1900lbs
Crr - Coefficient of rolling resistance 0.010
Cd - Coefficient of drag (stock) 0.35
A - frontal area 25.6
CdA 9.03 ft2 / 0.84 m2
Fuel energy density (Wh/US gal.) 32970Wh/112,500BTU
Engine efficiency .22
Drivetrain efficiency .95
Parasitic overhead, eg. at idle (optional, in Watts) 0
Air Density (rho) in kg/m3 1.22@15C/59F

Standard 0.35 Cd - stock body

MPH KM/H Aero (a) Rolling (b) Total % Aero % Rolling Watts HP HP Aero HP Rolling MPG(US) L/100km
5 8 2.56 84.55 87.10 2.94% 97.06% 194.69 0.26 0.01 0.25 176.97 1.33
10 16 10.23 84.55 94.77 10.79% 89.21% 423.67 0.57 0.06 0.51 162.64 1.45
15 24 23.01 84.55 107.56 21.39% 78.61% 721.22 0.97 0.21 0.76 143.31 1.64
20 32 40.91 84.55 125.45 32.61% 67.39% 1,121.64 1.50 0.49 1.01 122.87 1.91
25 40 63.92 84.55 148.46 43.05% 56.95% 1,659.22 2.23 0.96 1.27 103.82 2.27
30 48 92.04 84.55 176.59 52.12% 47.88% 2,368.24 3.18 1.66 1.52 87.29 2.69
35 56 125.28 84.55 209.82 59.71% 40.29% 3,282.98 4.40 2.63 1.77 73.46 3.20
40 64 163.63 84.55 248.17 65.93% 34.07% 4,437.75 5.95 3.92 2.03 62.11 3.79
45 72 207.09 84.55 291.64 71.01% 28.99% 5,866.82 7.87 5.59 2.28 52.85 4.45
50 80 255.67 84.55 340.22 75.15% 24.85% 7,604.49 10.20 7.66 2.53 45.31 5.19
55 89 309.36 84.55 393.91 78.54% 21.46% 9,685.05 12.99 10.20 2.79 39.13 6.01
60 97 368.17 84.55 452.71 81.32% 18.68% 12,142.78 16.28 13.24 3.04 34.05 6.91
65 105 432.08 84.55 516.63 83.64% 16.36% 15,011.97 20.13 16.84 3.29 29.84 7.88
70 113 501.11 84.55 585.66 85.56% 14.44% 18,326.91 24.58 21.03 3.55 26.32 8.94
75 121 575.26 84.55 659.80 87.19% 12.81% 22,121.88 29.67 25.86 3.80 23.36 10.07
80 129 654.52 84.55 739.06 88.56% 11.44% 26,431.19 35.44 31.39 4.05 20.86 11.28
85 137 738.89 84.55 823.43 89.73% 10.27% 31,289.11 41.96 37.65 4.31 18.72 12.57

Ideal 0.17 Cd - after streamlining

MPH KM/H Aero (a) Rolling (b) Total % Aero % Rolling Watts HP HP Aero HP Rolling MPG(US) L/100km
5 8 1.24 84.55 85.79 1.45% 98.55% 191.75 0.26 0.00 0.25 179.68 1.31
10 16 4.97 84.55 89.51 5.55% 94.45% 400.16 0.54 0.03 0.51 172.20 1.37
15 24 11.18 84.55 95.72 11.68% 88.32% 641.87 0.86 0.10 0.76 161.03 1.46
20 32 19.87 84.55 104.41 19.03% 80.97% 933.55 1.25 0.24 1.01 147.62 1.59
25 40 31.05 84.55 115.59 26.86% 73.14% 1,291.84 1.73 0.47 1.27 133.35 1.76
30 48 44.71 84.55 129.25 34.59% 65.41% 1,733.41 2.32 0.80 1.52 119.26 1.97
35 56 60.85 84.55 145.39 41.85% 58.15% 2,274.90 3.05 1.28 1.77 106.02 2.22
40 64 79.48 84.55 164.02 48.46% 51.54% 2,932.98 3.93 1.91 2.03 93.98 2.50
45 72 100.59 84.55 185.13 54.33% 45.67% 3,724.29 4.99 2.71 2.28 83.26 2.83
50 80 124.18 84.55 208.73 59.50% 40.50% 4,665.48 6.26 3.72 2.53 73.85 3.19
55 89 150.26 84.55 234.81 63.99% 36.01% 5,773.23 7.74 4.95 2.79 65.65 3.58
60 97 178.82 84.55 263.37 67.90% 32.10% 7,064.17 9.47 6.43 3.04 58.53 4.02
65 105 209.87 84.55 294.41 71.28% 28.72% 8,554.96 11.47 8.18 3.29 52.36 4.49
70 113 243.40 84.55 327.94 74.22% 25.78% 10,262.26 13.76 10.21 3.55 47.00 5.00
75 121 279.41 84.55 363.96 76.77% 23.23% 12,202.72 16.36 12.56 3.80 42.35 5.55
80 129 317.91 84.55 402.45 78.99% 21.01% 14,393.00 19.30 15.25 4.05 38.30 6.14
85 137 358.89 84.55 443.43 80.93% 19.07% 16,849.75 22.60 18.29 4.31 34.76 6.77

Conservative 0.26 Cd - after streamlining

MPH KM/H Aero (a) Rolling (b) Total % Aero % Rolling Watts HP HP Aero HP Rolling MPG(US) L/100km
5 8 1.90 84.55 86.44 2.20% 97.80% 193.22 0.26 0.01 0.25 178.31 1.32
10 16 7.60 84.55 92.14 8.24% 91.76% 411.91 0.55 0.05 0.51 167.29 1.41
15 24 17.09 84.55 101.64 16.82% 83.18% 681.55 0.91 0.15 0.76 151.66 1.55
20 32 30.39 84.55 114.93 26.44% 73.56% 1,027.60 1.38 0.36 1.01 134.11 1.75
25 40 47.48 84.55 132.03 35.96% 64.04% 1,475.53 1.98 0.71 1.27 116.75 2.01
30 48 68.37 84.55 152.92 44.71% 55.29% 2,050.82 2.75 1.23 1.52 100.80 2.33
35 56 93.06 84.55 177.61 52.40% 47.60% 2,778.94 3.73 1.95 1.77 86.79 2.71
40 64 121.55 84.55 206.10 58.98% 41.02% 3,685.36 4.94 2.91 2.03 74.79 3.14
45 72 153.84 84.55 238.39 64.53% 35.47% 4,795.55 6.43 4.15 2.28 64.66 3.64
50 80 189.93 84.55 274.47 69.20% 30.80% 6,134.99 8.23 5.69 2.53 56.16 4.19
55 89 229.81 84.55 314.36 73.11% 26.89% 7,729.14 10.36 7.58 2.79 49.03 4.80
60 97 273.49 84.55 358.04 76.39% 23.61% 9,603.47 12.88 9.84 3.04 43.05 5.46
65 105 320.98 84.55 405.52 79.15% 20.85% 11,783.46 15.80 12.51 3.29 38.01 6.19
70 113 372.26 84.55 456.80 81.49% 18.51% 14,294.58 19.17 15.62 3.55 33.74 6.97
75 121 427.33 84.55 511.88 83.48% 16.52% 17,162.30 23.02 19.21 3.80 30.11 7.81
80 129 486.21 84.55 570.76 85.19% 14.81% 20,412.10 27.37 23.32 4.05 27.01 8.71
85 137 548.89 84.55 633.43 86.65% 13.35% 24,069.43 32.28 27.97 4.31 24.33 9.67

Main features, safety and economy

Engine size 698 ccm (42.59 cubic inches)
Fuel type Gasoline
Fuel mixed driving 4.7 litres/100 km (50.05 miles per gallon)
Seats 2
Drive Rear wheels
Transmission Automatic, 6-speed
Airbags Optional front air bags.
Weight 805 kg (1,774.7 pounds)
Max weight with load 990 kg (2,182.6 pounds)
Towing weight 750 kg (1,653.5 pounds)
Overall length 2510 mm (98.8 inches)
Overall width 1520 mm (59.8 inches)
Overall height 1560 mm (61.4 inches)
Wheelbase 1820 mm (71.7 inches)
Fuel capacity 33.0 litres (8.72 gallons)

Engine and transmission

Engine location Rear, transverse
Displacement 698 ccm (42.59 cubic inches)
Engine type Inline, 3 cylinder
Max power 61.00 PS (45 kW or 60 HP) at 5250 Rev. per min.
Max torque 95.00 Nm (9.7 kgf-m or 70.1 ft.lbs) at 2000 Rev. per min.
Compression 9.0:1
Bore x stroke 665.0 x 67.0 mm (26.2 x 2.6 inches)
Fuel system Turbo
Valves per cylinder 2
Fuel control Overhead cam (OHC)
Cooling system Liquid
Gearbox Automatic, 6-speed

Speed and acceleration

Top speed 135.0 km/h (83.9 mph)
0-100 km/h (0-62 mph) 15.5 seconds
Power/weight ratio 0.0758 PS/kg
Exterior and interior
Chassis type Hatchback
Max no. of doors 2
Cargo space 150 litres (40 gallons)
Optional cargo space 150 litres (40 gallons)

Air and Rolling Resistance

Car Cd Area (sq ft) Cd x Area
Toyota Prius 0.26 27.7 7.20
Toyota Aygo 0.30 25.5 7.65 (+6%)
smart fortwo 6) 0.35 25.8 9.03 (+25%)

Steering, brakes and tires

Steering Power assisted steering. Traction control. Electronic stabilasation program (ESP). Traction control. Electronic stabilasation program (ESP).
Brake details ABS Antiblocking system (ABS). Antiblocking system (ABS).
Front tire dimensions 195/50-R15
Rear tire dimensions 205/50-R15 (23.1" diameter)

Bulb Inventory

source

Smart Coupe Mk6, Mk7, fortwo and all Cabrios ECE BSN
High Beam H1 448
Low Beam H7 499
Front Fog Light H3 453
Side Light W5W 501
Side Repeater W5W Amber 501A
Front Indicator PY21W 581
High Level Brake Light W2.3W 284
Number Plate & Rear Interior C5W 39mm 239
Speedo, Rev/Clock Pods and Heater Lighting T5 509T
Rear Brake/Tail Light P21/5W 380
Rear Indicator PY21W 581
Reverse Light P21W 382
Rear Fog Light P21W 382
Front Interior T5 509T

Electric

Parts List

Item Model Price Notes
Motor AC-50 7) 8) 9) 10) 11) 12) Needs to be at least a 35HP/60HP (continuous/peak) brushless outrunner
Belt or Chain HTD style Belt wide style which can tolerate upwards of 60HP
Speed Controller (ESC) Castle Phoenix 13)
Voltage Regulator Needed for powering 12V equipment
Battery Connectors Deans UltraPlugs ?? $5/pair These can handle upwards of 200A at 50V, with ZERO resistive losses. They're also relatively cheap, and idiot-proof to connect - what could go wrong 8-)
Motor Connectors
Motor Mount
Wire

Battery Options

LiFePO4 battery chemistry; a mass-produced battery chemistry that's expensive, but ideal for EV use.

Construction Details

Rear Drive

Power Supply

312VDC is required to generate a 220VAC (312V peak) sine wave. This is a common voltage for a 3 phase AC motor. Most motor controllers are powered by 312VDC internally, so this is why I am using such a high voltage.

Motor Selection

It must be an AC motor…I love Tesla's tech, and I'm not touching any of that DC motor sillyness. I'm playing with the idea of a brushless outrunner, simply because of the insane amount of torque you can pull from them, but…custom motors are expensive! So, a more traditional squirrel cage three-phase AC motor will suffice.

Motor Considerations

Model Torque Peak RPM Voltage Current Photo
AC24LS
Nothing was found.

Motor Mount

Motor Pulley Discussion

Engineering Discussions

For the drag-racers

Design Improvements

Throttle

Speed Controller

Clutch Bearing

Hydraulic

Inspirations: 14) 15)

Math

When using an online calculator.

  1. Vehicle Weight: 2000lbs
  2. Wheel Diameter: 23.1“ (cir: 55.25”)
  3. Frontal Area 25sq-ft (CoD: 0.35)
  4. Acceleration Factor (0-60MPH in 11sec): 14

Using above pump and motor combination:

Grade Maximum speed
0% 80MPH
1% 72MPH
2% 65MPH
3% 60MPH
4% 55MPH
5% 50MPH

Parts List (3000PSI)

Item Model Price Notes
Motor 1100RPM at each rear wheel (max speed: ~78MPH)
Pump ~24GPM
Accumulator 2 gallon (piston) $489 1.82 gallons will enable 0-60 in 9 seconds w/ a 7.6cir16) pump on 23.1“ wheels (4.26 gallons will do 0-60MPH in 5secs w/ 13.6cir motors)
Lines 1” diameter or larger
Oil Regulator Must be aluminum
Engine Diesel, minimum continuous: 35HP

Construction Details

Rear Drive

Wheel mounted hydraulic motors.

Motor Considerations

Model Torque Continuous RPM GPM in3/min Notes

Motor Mount

Engineering Discussions

For the drag-racers

If you want to go from zero to sixty MPH in ten seconds, you'll need sufficient accumulators for approximately 334 feet of travel.

Assuming a constant rate of acceleration, we can use the following formula:

D = (Vf + Vo)*t/2

where:

  1. D is the unknown distance
  2. Vf is the final speed
  3. Vo is the initial speed
  4. t is the elapsed time

In this case we have that:

  1. Vf = 60 mph = 1/60 miles per second (mps)
  2. Vo = 0 mph = 0 mps
  3. D is unknown
  4. t = 10 s

Then the distance traveled during the 10 second 0-60 acceleration period becomes:

D = (1/60)*10/2 = 0.08333 miles

Design Improvements

Throttle

Engine

Well, something has to provide the power :-)

Diesel Engine Considerations

Model RPM17) HP Notes
Yamnar L100 Yea, it's a small engine…but its also sitting in the garage :-). Confirm that the fuel injector pump is in-fact a 100PSI pump.
D850 2500 15 A more realistic engine option, if turbocharged.

Turbocharging

Model Boost18) Volume19) Notes
RHB31 Often recommended on SuckinDiesel Forums and found on http://www.dieselbike.net
VZ21 World's “smallest” turbocharger
Altmann Some interesting thoughts and illustrations here.
smarthev.txt · Last modified: 2014/05/16 12:35 (external edit)
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