smart fortwo mhd test results - Transports Canada

smart fortwo mhd 

Advanced Gasoline 

Idle Start Stop Technology 

Test Results Report 

June 2010

Disclaimer notice 

Transport Canada's ecoTECHNOLOGY for Vehicles program ("eTV") tests emerging vehicle 

technologies to assess their performance in accordance with established Canadian motor vehicle 

standards. The test results presented herein do not, in themselves, represent an official determination 

by Transport Canada regarding fuel consumption or compliance with safety and emission standards of 

any motor vehicle or motor vehicle component. Transport Canada does not certify, approve or endorse 

any motor vehicle product. Technologies selected for evaluation, and test results, are not intended to 

convey policy or recommendations on behalf of Transport Canada or the Government of Canada. 

Transport Canada and more generally the Government of Canada make no representation or warranty 

of any kind, either express or implied, as to the technologies selected for testing and evaluation by 

eTV, nor as to their fitness for any particular use. Transport Canada and more generally the 

Government of Canada do not assume nor accept any liability arising from any use of the information 

and applications contained or provided on or through these test results. Transport Canada and more 

generally the Government of Canada do not assume nor accept any liability arising from any use of 

third party sourced content. 

Any comments concerning its content should be directed to: 

Transport Canada 

Environmental Initiatives (AHEC) 

ecoTECHNOLOGY for Vehicles (eTV) Program 

330 Sparks Street 

Place de Ville, Tower C 

Ottawa, Ontario 

K1A 0N5 

E-mail: eTV@tc.gc.ca 

© Her Majesty in Right of Canada, as represented by the Minister of Transport, 2009-2010

Table of Contents 

EXECUTIVE SUMMARY .............................................................................................. 4 

1.0 INTRODUCTION................................................................................................. 7 

2.0 TESTING PROGRAM......................................................................................... 7 

3.0 TESTING LOCATIONS...................................................................................... 8 

4.0 VEHICLE OVERVIEW ...................................................................................... 8 

5.0 PHASE I - LABORATORY TESTING............................................................ 10 

5.1 RESULTS ............................................................................................................ 11 

5.1.1 2-Cycle Fuel Consumption Results........................................................... 12 

5.1.2 5-Cycle Fuel Consumption Results........................................................... 13 

5.1.3 New York City Cycle Fuel Consumption Results...................................... 15 

5.1.4 Emissions Results...................................................................................... 16 

5.1.5 Idling Duration Experiment...................................................................... 17 

6.0 PHASE II – DYNAMIC TESTING................................................................... 19 

6.1 ACCELERATION EVALUATION............................................................................ 20 

6.2 MAXIMUM SPEED IN GEAR ................................................................................ 20 

6.3 HANDLING ......................................................................................................... 21 

6.3.1 Lateral Skid Pad ....................................................................................... 21 

6.3.2 Emergency Lane Change Manoeuvre....................................................... 23 

6.4 NOISE EMISSIONS TESTS.................................................................................... 25 

6.5 BRAKING............................................................................................................ 28 

6.6 SUMMARY REMARKS REGARDING DYNAMIC TESTING........................................ 29 

7.0 PHASE III - ON-ROAD EVALUATIONS....................................................... 29 

8.0 CONCLUSIONS ................................................................................................. 30 

9.0 WHAT DOES THIS MEAN FOR CANADIANS?.......................................... 31

EXECUTIVE SUMMARY 

The smart car has been one of the most fuel-efficient vehicles in the two-seater class 

since it was first introduced in Canada in 2004. Currently, smart models are sold with a 

gas engine in Canada and the United States, while the diesel model is sold in Mexico, 

Europe and other world markets and a fully electric model will be released in the United 

Kingdom in the near future. 

The eTV program selected the smart fortwo micro hybrid drive (mhd) for testing and 

evaluation because of its idle start-stop system. Anti-idling or start-stop technology is 

designed to reduce fuel consumption and exhaust emissions during periods of urban 

driving. These systems are relatively rare within the Canadian market and are generally 

limited to vehicles that are full hybrids. Thus, the anti-idling technology, combined with 

the base smart’s impressive fuel efficiency made the smart mhd an ideal vehicle for 

inclusion in the eTV program. 

It should be noted that, despite its name and the inclusion of the idle start-stop 

technology, the European smart fortwo mhd is not a full hybrid. In acquiring the smart 

mhd, the eTV program wanted to quantify the fuel savings that could result from the idle 

start-stop system as well as how it performed under a variety of Canadian climatic 

conditions, particularly in city driving and in cold weather. The vehicle was tested and 

evaluated over three phases: laboratory fuel consumption and exhaust emissions; 

dynamic track testing; and on-road evaluations. The following is a summary of the 

results obtained from these evaluations. 

Criteria 

Results 

Fuel consumption In 2-cycle testing, with the idle start-stop (eco-mode) turned ON, 

the fuel consumption values are 6.20 L/100 km for the city, 

5.12 L/100 km for the highway and 5.71 L/100 km for combined 

city/highway. 

In all testing cycles, the use of idle start-stop offers considerable 

savings in fuel consumption in city driving. 

CO 2 emissions 

Testing cycle No idle With idle % savings 

start-stop start-stop 

2-cycle 6.45 6.20 4.0% 

5-cycle 7.47 7.10 5.0% 

NYCC 10.26 9.08 11.5% 

Real-world 5.18 4.68 9.7% 

In combined city and highway testing, with the idle start-stop (ecomode) 

turned ON, the smart mhd obtained an adjusted value of 

137 g/km, which is 10% less than the current best performers in the 

sub-compact class and a 40% improvement over all models within its 

class. 

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ecoTECHNOLOGY for Vehicles 4

Criteria 

Exhaust Emissions 

Idle Start-Stop 

Performance Results 

Dynamic 

Performance 

Driver Evaluations 

Results 

With regard to non-CO 2 exhaust emissions, the 2009 smart mhd meets 

the Euro V emissions standards for which it was designed and is well 

below the Tier 2, Bin 5 standards in effect in Canada. 

The smart mhd is able to operate between -7C and 40C, using various 

combinations of the auxiliary systems. However, below -7C, the 

vehicle did not allow the eco-mode to engage and turn off the engine 

when idling, despite acceptable battery voltage levels. This is by design 

of the manufacturer. 

Overall, handling and performance were good, pass or acceptable 

relative to the sub-compact class. As such, dynamic performance 

would not pose a barrier to its inclusion in the fleet of sub-compact 

vehicles in Canada. 

The smart mhd reached an average maximum speed of 144.2 km/h 

in approximately 40 seconds while operating in 4 th gear. 

The maximum lateral acceleration was 6.3 m/s 2 for a 61 m turning 

circle. 

Emergency lane change performance is rated as good. 

External and internal noise levels were well below the limits set out 

in the CMVSS. 

Braking is compliant with all aspects of the CMVSS 135 standard. 

The majority of the evaluators reported that they were comfortable with 

the idle start-stop system, even in heavy traffic. In a comparison test 

with a smart fortwo not equipped with anti-idling technology, the smart 

mhd obtained significant fuel savings. With regards to general 

performance and handling several evaluators noted “jerky” shifting of 

the transmission as an issue. 

Barriers to the Introduction of Idle Start-Stop Technologies into the Canadian 

Market 

Public opinion research has generally established that fuel consumption and vehicle 

emissions have not traditionally been of primary importance to the Canadian consumer 

when shopping for a new vehicle 1 . One of the principle barriers to the introduction of 

advanced gasoline technologies, such as idle start-stop, is overcoming the consumer’s 

desire to minimize the initial purchase price (or ‘sticker shock’) of a new vehicle, often at 

the expense of longer-term operating costs and environmental impacts. Conversely, 

innovative technologies that improve fuel efficiency often increase the initial purchase 

price of a vehicle. When confronted with the choice of paying more for advanced vehicle 

technologies such as idle stop-start, consumers often opt for a lower initial purchase 

price, unaware of the potential savings that the technology might offer. 

1 Pollution Probe. 2008. Barriers to Consumer Purchasing of More Highly Fuel-Efficient Vehicles: A 

Background Paper. 

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In addition, fuel consumption test procedures and vehicle ratings can under-estimate the 

potential real-world benefits of advanced technologies. The results outlined in this report 

support that point, since the 2-cycle tests under-represent the fuel savings obtained both 

in the urban-centred New York City Cycle driving cycle and in real-world driving. In 

these situations, not only does the vehicle cost more, but also there appears to be little 

improvement in the vehicle’s published fuel consumption ratings – a situation that 

compounds existing consumer barriers. 

As well, the development of codes and standards needs to keep pace with the innovation 

in new vehicle technologies, in order to ensure the safety, efficiency and suitability of the 

Canadian transportation system. The kind of testing that eTV has undertaken in relation 

to idle stop-start technologies, for example, is essential in helping to engage industry and 

stakeholders in leading-edge research to support the development of new or modified 

codes and standards for all technologies, including advanced gasoline technologies. 

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1.0 INTRODUCTION 

The first smart car was introduced in Canada in late 2004 and sold through Mercedes- 

Benz dealers. Currently, in Canada, smart cars are sold only with a gas engine. A diesel 

model is sold in Mexico and Europe and a fully electric model is intended for release in 

the United Kingdom in the near future. 

Working in partnership with Mercedes-Benz, the eTV program selected the European 

model smart fortwo mhd for testing because it is equipped with an innovative idle startstop 

system. This anti-idling technology is designed to reduce fuel consumption and 

exhaust emissions during periods of urban driving. Idle start-stop systems are relatively 

rare within the Canadian market and are generally limited to vehicles that are full 

hybrids. Thus, the anti-idling technology, combined with the smart’s impressive fuel 

efficiency made the smart mhd an ideal vehicle for inclusion within the eTV program. 

The engine found in the European smart fortwo micro hybrid drive (mhd) is a standard 

smart fortwo engine, equipped with ‘start-stop’ technology. While its name suggests that 

vehicle is a micro hybrid, no additional battery pack has been added. Rather, the standard 

lead-acid battery has been replaced with an absorbed glass mat (AGM) battery, and the 

alternator and starter motor have been replaced with a belt-driven electric startergenerator. 

The start-stop system operates when the vehicle comes to a stop, either at a traffic light or 

in stop-and-go traffic. As the vehicle comes to a stop, the internal combustion engine 

switches off. As soon as the driver releases the brake pedal, the electric motor acts as the 

starter and instantly switches the internal combustion engine back on. During normal 

driving the electric motor behaves like a generator, providing power to recharge the 

AGM battery. According to manufacturer specifications, keeping idling to a minimum 

with this advanced technology reduces urban fuel consumption by more than 15%. 

2.0 TESTING PROGRAM 

The testing program was designed to provide a fair assessment of the idle start-stop 

technology found on the smart mhd as well as the vehicle’s fuel consumption, exhaust 

emissions and overall handling, both with the idle start-stop system turned on and turned 

off. The suggested tests were based on practices used by the Canadian Corporate 

Average Fuel Consumption (CAFC), the U.S. Environmental Protection Agency, the U.S. 

Department of Tranport, the International Standards Organization and the Society of 

Automotive Engineers (see smart fortwo mhd Test Plan for details). 

The smart mhd was evaluated over three distinct phases: 

Phase I - Laboratory fuel consumption and exhaust emissions testing 

Phase II - Dynamic track testing 

Phase III - On-road evaluations 

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Together, these various phases were designed to realistically assess the smart mhd’s 

overall performance and identify any possible barriers that could adversely affect the 

introduction of its advanced technologies into the Canadian market. 

3.0 TESTING LOCATIONS 

Phase I testing was performed in partnership with Environment Canada at the Emissions 

Measurement and Research Division (ERMD) located in Ottawa, Ontario. All testing 

was performed in a controlled laboratory, using a vehicle chassis dynamometer. The 

laboratory environment ensures that testing was completed to within ± 1 degree Celsius 

of the required test temperature. Vehicles are tested according to separate driving cycles 

and are maintained to within ± 1.5 km/h of the required speed. 

Additionally, since the vehicle was already in the Pacific Region for use by Transport 

Canada staff prior to and during the 2010 Olympic and Paralympic Winter Games, we 

were able to supplement Phase I testing by evaluating the vehicle at different speeds, 

temperatures and loads at the National Research Council (NRC) laboratories located on 

the University of British Columbia’s campus. 

Phase II testing was performed at Transport Canada’s test track facility in Blainville, 

Québec. The controlled environment was necessary to ensure that testing was performed 

on a gradient of ± 1%. The test track is equipped with over 25 kilometres of road, 

including both a high-speed and low-speed circuit, to allow for a variety of tests. Phase II 

testing was performed between September 15 and October 13, 2009. Tests were carried 

out only in weather conditions that were favourable to evaluation and testing standards. 

Phase III vehicle evaluations were preformed by Transport Canada staff, as well as by 

automotive journalists at the program’s public outreach events. In addition, in 

partnership with Transport Canada’s Olympic Planning Secretariat, the vehicle was 

driven by a number of inspectors before and during the 2010 Winter Games. The 

inspectors provided interesting insights regarding the smart mhd’s performance under 

real-world conditions as they travelled throughout British Columbia to carry out their 

regular inspection duties. 

4.0 VEHICLE OVERVIEW 

The smart fortwo mhd is classified as a two-seater sub-compact vehicle. It is equipped 

with a 999 cc (~1 litre), naturally aspirated, 3-cylinder engine. The vehicle is also 

equipped with other technologies, such as low rolling resistance tires, which help to limit 

fuel consumption and GHG emissions. Additionally, the moon roof is constructed of 

lightweight polycarbonate rather than glass, offering a 40% reduction in weight. In 

available documentation, the smart fortwo mhd is described as being capable of 

achieving 767 km on a 33-L tank of fuel, based on a European combined fuel 

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consumption rating of 4.3 L/100 km and producing only 103 g/km of CO 2 . The 

specifications for the vehicle are presented in the table below. 

Weight 750 kg Drive Type Rear-wheel 

Length 2.70 m Engine In-line 3-cylinder, naturally 

aspirated, with idle start-stop 

Width 1.56 m Transmission 5-speed automatic 

Height 1.54 m Torque 92 Nm / 68 lb-ft @ 4,500 rpm 

Seating 2 Power 52 kW / 70 hp @ 5,800 rpm 

Fuel Type Gasoline (95 Octane) Fuel Efficiency 

City 

Highway 

5.1 L/100 km 

3.8 L/100 km 

Displacement 999 cm 3 Fuel Tank Capacity 33 L 

Top Speed 145 km/h Driving Range 767 km (based on European 

driving cycles) 

Acceleration 0-100 in 13.3 seconds Brakes (f/r) Disc / Drum 

CO 2 Emissions 103 g/km Drag Coefficient 0.34 

Table 1: Specifications for the smart fortwo mhd 

This particular engine/power train model was chosen because it closely resembles an 

equivalent Canadian model in terms of accessories, engine displacement, power, torque 

and weight. In the smart fortwo mhd, the starter and alternator have been replaced by an 

electric starter-generator. The mhd system cuts the engine when the vehicle speed drops 

below 8 km/h (about 5 mph). It automatically re-starts the engine when the driver 

releases the brakes. Based on available information, the use of the mhd system has the 

potential of improving fuel consumption by as much as 15% in the city. 

In addition to the idle stop-start system, the smart mhd offers other environmentally 

friendly advanced features such as lightweight materials, which decrease fuel 

consumption and reduce GHG emissions and criteria air contaminants. 

Figure 1: smart fortwo mhd 

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The user can control the idle start-stop system by switching the eco-mode button ON or 

OFF. While the system is switched off, the vehicle will idle at all stops. If the driver 

chooses the ON position, however, the idle start-stop system will engage when the 

vehicle is idling, shutting off the motor. A picture of the smart mhd belt-driven idle startstop 

system is provided below. 

Figure 2: smart mhd Belt-Driven Idle Start-Stop System 

5.0 PHASE I - LABORATORY TESTING 

More than 3,500 kilometres of vehicle and engine use were accumulated on the smart 

mhd, in keeping with the Code of Federal Regulations (CFR) mileage accumulation 

procedure. The procedure outlines the prescribed route that the vehicle must follow, 

using commercially available gasoline fuel with an octane rating of 91 or higher. Once 

mileage accumulation was completed, the vehicle was soaked 2 at a laboratory 

temperature for no less than 8 hours before testing began. This is to ensure that the 

vehicle’s test temperature is controlled for comparison against other test vehicles 

undergoing the same emissions and fuel consumption evaluations. 

Emissions and fuel consumption tests were performed, as per the standard CFR 

procedures. Evaluations were performed over the six duty cycles listed in Table 2. Each 

set of tests was performed with the eco-mode engaged and disengaged (denoted as ON 

and OFF), for comparative analysis. 

2 To soak a vehicle means to park it in the test chamber with the engine turned off and allow the entire 

vehicle, including engine, fluids, transmission and drive train, to reach the test cell temperature prior to the 

beginning of a test. 

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Test Parameter Testing Standard Number of Tests 

(Cell Temperature) 

Location 

Urban Driving U.S. FTP-75 4 (25°C) ERMD (Ottawa, ON) 

Cold Test U.S. FTP-72 2 (-7°C) ERMD (Ottawa, ON) 

Aggressive Driving US06 (SFTP) 2 (25°C) ERMD (Ottawa, ON) 

Highway Driving U.S. HWFET 4 (25°C) ERMD (Ottawa, ON) 

Electrical Load US SC03 2 (25°C) ERMD (Ottawa, ON) 

Stop-and-Go Driving US NYCC 4 (25°C) ERMD (Ottawa, ON) 

Table 2: Chassis Dynamometer Test Schedule 

The vehicle was mounted on a chassis dynamometer where the rear (drive) wheels were 

allowed to roll against a resistance drum. The drum’s resistance was pre-programmed, 

using the vehicle’s road load force parameters. Parameters and coefficients were based 

on a vehicle travelling from a speed of 115 km/h to 15 km/h (71.5 mph to 9.3 mph) 

while coasting. The final result was a model for road load force as a function of speed, 

during operation on a dry, level road, under reference conditions of 20°C (68°F) and 

98.2 kPa (29.0 in-Hg), with no wind or precipitation and with the transmission in neutral. 

ERMD collected and analyzed exhaust emissions for each of the duty cycles listed in 

Table 2. The emissions data were analyzed for: 

carbon monoxide 

carbon dioxide 

total hydrocarbons 

nitrogen oxides 

5.1 RESULTS 

The fuel consumption estimate for the smart fortwo mhd is based on calculations for both 

the 2-cycle city and highway driving cycles and the 5-cycle city, highway, cold test, 

aggressive driving and electrical load driving cycles. The test cycles are derived from 

extensive data on real-world driving conditions, such as driving activity, trip length and 

stopping frequency, among other factors. 

The 2-cycle calculation is the total result of the urban driving cycle (U.S. FTP-75) and 

the highway duty cycle (U.S. HWFET), using a ratio of 55% city to 45% highway. The 

cycles are then adjusted upward 10% and 15% respectively to account for “real-world” 

differences between the way vehicles are driven on the road and over the test cycles. The 

end result is a combined fuel consumption rating for the vehicle in addition to separate 

city and highway results. These are the procedures followed by Natural Resources 

Canada to determine the values that are published in their annual Canadian Fuel 

Consumption Guide. 

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The 5-cycle test method is used to supplement the Canadian 2-cycle test method. It takes 

into account several factors that affect fuel consumption but are not addressed in the 

current Canadian standard. The U.S. Environmental Protection Agency began to 

implement 5-cycle testing in 2006. 

The 5-cycle method includes actual testing over a wider range of driving patterns and 

temperature conditions than those tested under the current Canadian standard. For 

example, in the real world, vehicles are often driven more aggressively, at higher speeds 

and with greater rates of acceleration demand placed on the engine than existing city and 

highway test cycles can duplicate. The US06 aggressive driving cycle takes this into 

account. Furthermore, drivers often use air conditioning in warm and/or humid 

conditions. In the 2-cycle calculation, this factor is not taken into consideration, since the 

test does not allow the air conditioning system to be turned on. The US SC03 test cycle 

reflects the added fuel needed to operate the air conditioning system. As well, given 

Canada’s climate, a typical vehicle will be driven below 0°C (~32°F) on a fairly regular 

basis. The current 2-cycle testing is conducted only at 25°C (~ 77°F). The U.S. FTP-72 

cold test cycle (-7°C/~ 20°F) is used to reflect the additional fuel needed to start and 

operate an engine at lower temperatures. 

Using the 5-cycle method, therefore, seems to offer a more accurate representation of the 

vehicle’s fuel consumption and overall performance than the 2-cycle method. However, 

both methods apply some adjustment factors to take into account other real-world driving 

factors such as road grade, wind, low tire pressure and fuel quality. Because it takes 

other factors into account, for the same make and model, the 5-cycle method usually 

yields fuel consumption values that are approximately 10 to 20% higher than those 

obtained using the 2-cycle method. 

5.1.1 2-Cycle Fuel Consumption Results 

The smart fortwo mhd was tested twice against the FTP-75 city cycle and the HWFET 

highway cycle, both with eco-mode ON and with eco-mode OFF, according to current 

Canadian standards for fuel consumption testing. The results were averaged for each 

cycle. 

The results for the fuel consumption of the smart fortwo mhd with the eco-mode ON, 

based on the 2-cycle calculations (adjusted 10% and 15% respectively) are 6.20 L/100km 

for the city and 5.12 L/100km for the highway. An adjusted combined fuel consumption 

value, using a 55% and 45% weighting for the city and highway respectively, is 

5.71 L/100km. 

With the eco-mode turned OFF, the adjusted 2-cycle calculations offer a fuel 

consumption of 6.45 L/100km for the city. Therefore, driving with the eco-mode turned 

on resulted in a 5%-savings in fuel in the city. It should be noted, however, that higher 

savings are possible, as the FTP-75 city cycle offers 23 stops, though their duration is 

quite short (< 5 seconds) in most cases. Therefore, the system’s full fuel savings are not 

entirely reflected through this particular cycle. The resulting combined fuel consumption 

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value, adjusted using a 55% and 45% weighting for the city and highway respectively, 

becomes 5.89 L/100 km. 

2- Cycle Fuel Consumption (L/100km) 

Adjusted Values City Highway Combined City Savings 

Eco-mode OFF 6.45 5.12 5.89 

Eco-mode ON 6.20 5.12 5.71 4.0% 

Table 3: Adjusted 2-Cycle Fuel Consumption Values 

Figure 3 below shows the unadjusted 3 2-cycle combined fuel consumption value of 

5.14 L/100 km versus the fleet average for model year 2009, as well as the Canadian 

(CAFC) and U.S. (CAFE) standards. It can be seen that the smart fortwo mhd is more 

than 40% below the 2009 model year CAFC standard of 8.60 L/100 km and more than 

26.5% below the actual fleet average achieved by all new cars in 2009. 

Vehicle Footprint Vs Fuel Consumption CAFE/CAFC - Cars 

12,0 

10,0 

Fuel Consumption (L/100 km) 

8,0 

6,0 

4,0 

2,0 

US 

Canada 

Fleet Average 

Target 

Smart mhd 

0,0 

0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0 

Vehicle Footprint (square feet) 

Figure 3: Unadjusted Fuel Consumption against Canadian and U.S. Standards 

5.1.2 5-Cycle Fuel Consumption Results 

Each of the 5-cycles is divided into “phases” – also referred to as “bags” because each 

phase sample is bagged and analyzed separately, without interruption, during the test. 

3 Fuel consumption standards are compared to unadjusted values in both Canada and the U.S. Adjusted 

values are used for labelling purposes only. 

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The following equations are derived from 40 CFR Parts 86 and 600, to determine both 

the city and highway fuel economy 4 results for a vehicle. 

Where: 

Bag # FE is the fuel economy in US miles per gallon of fuel during the specified bag of the FTP test 

conducted at an ambient temperature of 75ºF or 20ºF 

Under the vehicle specific 5-cycle formula, the highway fuel economy value would be 

calculated as follows: 

4 The term “fuel economy” is used here to reflect the fact that 5-cycle testing is a U.S. standard and not the 

Canadian standard. In Canada, the term “fuel consumption” is used. 

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The results for the fuel consumption of the smart fortwo mhd, based on the 5-cycle 

calculations above, are 7.10 L/100 km for the city and 6.22 L/100 km for the highway, 

with the eco-mode ON. When the eco-mode ON values are compared to the eco-mode 

OFF values for 5-cycle testing, the eco-mode ON offers a 5% fuel savings in city driving. 

5- Cycle Calculated Vehicle Specific Fuel Consumption (L/100km) 

City Highway Combined City Savings 

Eco-mode OFF 7.47 6.22 6.91 

Eco-mode ON 7.10 6.22 6.70 5.0% 

Table 4: 5-Cycle Fuel Consumption Values 

Although these fuel consumption values are higher than those obtained during the 2-cycle 

testing, the 5-cycle testing values provide a more accurate representation of what a driver 

can expect in terms of real-world fuel consumption. When compared against the city and 

highway values for the 2-cycle calculation, the 5-cycle fuel consumption values are 13% 

and 18% higher for city and highway driving respectively. 

5.1.3 New York City Cycle Fuel Consumption Results 

The New York City Cycle (NYCC) is a standard emissions cycle developed by the U.S. 

Environmental Protection Agency (EPA). This cycle is not used for emissions or fuel 

consumption regulations for light-duty vehicles. However, the NYCC cycle is often used 

in hybrid vehicle research, to help determine the effective range of a hybrid vehicle in 

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city stop-and-go traffic. This cycle was used with the smart fortwo mhd because it offers 

a more accurate representation of city driving, with quick accelerations from a start and 

longer periods of idling. The cycle was run twice with the idle start-stop system engaged 

and twice with it disengaged, with the results averaged for each mode. 

NYCC Fuel Consumption (L/100km) 

City 

City Savings 

Eco-mode OFF 10.26 

Eco-mode ON 9.08 11.5% 

Table 5: New York City Cycle Fuel Consumption Values 

As the results in the table above demonstrate, the smart fortwo mhd offers an 11.5% 

savings in fuel in the laboratory when tested against the NYCC. Although, the laboratory 

offers a well-controlled environment, its simulated real-world driving yields slightly 

different results than those presented in the previous sections. 

It can be inferred from the results presented that the standard fuel consumption cycles 

(both the Canadian 2-cycle and the U.S. 5-cycle) may under-estimate the full fuel savings 

potential of an idle start-stop system. The stops in these cycles are limited in number and 

very short (less than 5 seconds). The NYCC, with longer stop periods that are more 

consistent with real-world driving conditions, demonstrates results that are 7% better than 

the current regulated cycles. The eTV program will continue to work with stakeholders, 

inlcuding government and industry, on better ways to demonstrate the full benefits of the 

idle start-stop technology. 

5.1.4 Emissions Results 

The results of the city and highway test cycles offer an adjusted combined CO 2 emissions 

value of 137 g/km. The two best performing comparable sub-compact vehicles for the 

same model year, currently available on the Canadian market, obtained CO 2 emissions 

value of 152 g/km CO 2 . Thus, technologies such as those found in the smart mhd 

could offer a 10% reduction in CO 2 emissions over the current best performers in the subcompact 

class. 

When compared to the national average of all sub-compact cars available in Canada, the 

CO 2 emissions reported for the same model year are 238 g/km. The smart mhd, therefore, 

offers a 40% improvement in CO 2 emissions over all models within its class. 

With regard to non-CO 2 exhaust emissions, the 2009 smart mhd meets the Euro V 

emissions standards for which it was designed. Additionally, the smart fortwo mhd is 

well below the Canadian emission standards against which it was tested. 

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Mode CO NMHC HCHO NOx CO 2 

smart mhd eco-mode OFF 

0.63 0.028 0.001 0.01 218 

smart mhd eco-mode ON 

0.64 0.057 0.002 0.01 207 

Standard – Bin 5 

3.4 0.075 0.015 0.05 - 

Euro 5 Emissions 

1.61 0.109 - 0.12 - 

Table 6: Federal Test Procedure 75 - Exhaust Emissions vs. Standards (g/mile) 

It should be noted that the values for non-methane hydrocarbons were slightly higher in 

both tests on the FTP-75, with the eco-mode engaged. Although still well below the limit 

established both in Canada and in Europe, the engine restarts may be causing this slight 

increase. There may be some small residence time effect within the exhaust sampling 

system that negatively assesses anti-idling systems but any such effect should be very 

minor to the point of being difficult to quantify. 

5.1.5 Idling Duration Experiment 

Although it was not included in the original test plan, the eTV program performed 

additional steady-state dynamometer tests at the NRC’s environmental chamber, located 

at the Institute for Fuel Cell Innovation in Vancouver, British Columbia. The test cell 

can simulate extreme temperatures, humidity, altitude and atmospheric conditions for 

evaluating clean energy technologies under steady dynamometer load settings. The 

testing was performed in partnership with the NRC’s testing staff as well as an 

Environment Canada field test team from ERMD. 

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Figure 4: smart mhd on Dynamometer at NRC Fuel Cell Institute 

The smart mhd was evaluated at 5% humidity at temperatures ranging from -10ºC to 

40ºC. The object of this experiment was to address concerns from Canadians regarding 

the performance of auxiliary systems and the ability of the start-stop system to function at 

cold and warm temperatures. The test procedure does not reflect any existing or 

proposed standard but does follow general procedures and practices normally associated 

with dynamometer testing and exhaust emissions analysis. 

Testing involved soaking the smart mhd at an initial temperature of -10ºC, after which the 

vehicle was driven against the resistance of the drums until the eco-mode was engaged 

(ON) 5 and with various combinations of auxiliary systems in use. The vehicle was 

slowed to a stop and allowed to remain at a standstill (anti-idle) for as long as possible. 

Table 7 below summarizes the findings. 

Cell Temperature 

(Celsius) 

Auxiliary Devices In Use Anti-Idle Duration Notes 

-10 Heater / Radio / Headlights 0 Minutes 

-7 Heater / Radio / Headlights 53 Minutes 

System did not engage at this 

temperature 

System engaged, cabin 

temperature begins to drop after 

5 minutes 

0 Heater / Radio / Headlights > 15 Minutes System engaged 

10 Radio / Headlights > 15 Minutes System engaged 

20 Radio / Headlights > 15 Minutes System engaged 

30 

40 

Air Conditioning / Radio / 

Headlights 

Air Conditioning / Radio / 

Headlights 

> 15 Minutes System engaged 

> 15 Minutes 

Table 7: Idle Stop-start Performance Results 

System engaged, cabin 

temperature begins to warm after 

4 minutes 

The experiment demonstrated that the smart mhd is able to operate between a 

temperature of –7ºC and 40ºC, while using various combinations of the auxiliary 

systems. However, below -7C, the vehicle would not allow the eco-mode to engage 

and turn off the engine, despite acceptable battery voltage levels. This –7C cut-off is 

intentional. The manufacturer deems the heating requirement below –7C to be such that 

the system would be repeatedly engaging and disengaging to the point of offering little in 

the way of fuel savings. 

Initially, we began testing the system to gauge the length of time during which it would 

remain off before the engine was forced to turn on. During the –7ºC trial, the vehicle was 

5 The eco-mode system will not engage on a cold start. Often, a few minutes of driving are required, 

depending on the ambient temperature, before the system will engage. 

__________________________________________________________________________________ 


anti-idling for 53 minutes before the engine came on. Given our time constraints and that 

most stops on Canadian public roads in traffic are less than 5 minutes, we tested for 

approximately 20 minutes at each subsequent temperature, and reported successful antiidle 

periods greater than 15 minutes. During all trials where the system was engaged, the 

idling system and the auxiliary accessories remained on. The only noticeable difference 

was that, at cold and very hot temperatures, the heater and the air conditioning began to 

blow either colder or warmer air, depending on the temperature outside the vehicle. 

Lastly, the idle start-stop system is controlled by the engine control unit (ECU), which 

monitors the battery voltage. When the battery is approaching its cut-off voltage, the idle 

start-stop system turns the engine on and the system remains on standby as the battery 

recharges. Thus, the ECU ensures that the vehicle does not turn off the engine when the 

battery cannot supply enough current to restart the engine and/or power the auxiliary 

accessories. 

6.0 PHASE II – DYNAMIC TESTING 

The smart fortwo mhd underwent dynamic and performance testing in September and 

October 2009. Most aspects of the tests performed were for general dynamic assessment 

purposes and not as a measure of compliance with the Canada Motor Vehicle Safety 

Standards (CMVSS). Concerns about fuel-efficient vehicles are not always limited to 

exhaust emissions and greenhouse gas reduction. The general dynamic testing was 

performed because the eTV program wished to assess how well smaller, more fuelefficient 

vehicles function in various road situations, with a view to identifying any 

possible issues. 

As mentioned previously, the dynamic testing was performed at Transports Canada’s test 

facility in Blainville, Québec. An aerial view of the test track is provided below. 

Figure 5: Dynamic Test Track Facility Overview 

__________________________________________________________________________________ 


6.1 ACCELERATION EVALUATION 

The maximum acceleration was determined by starting the vehicle from a standing start 

and following the procedure set out below. 

1. The vehicle was evaluated by accelerating to the maximum attainable speed in a 

quarter of a mile (402.3 m). 

2. The vehicle was evaluated by accelerating to the maximum attainable speed in a 

kilometre (1000 m). 

Shifting occurred at what was determined to be an optimal shift point. To account for 

variations in wind, the vehicle was driven in both directions on the test track, with the 

results averaged. 

Distance Speed ( km/hr ) 

1/4 mile ( 402.3 m) 106 

1,000 m 134 

Table 8: Average Speed Results for Specified Distances 

6.2 MAXIMUM SPEED IN GEAR 

The maximum speed attainable was tested and recorded for each gear. The driver started 

from a standing start for first gear only. The vehicle was accelerated, changing gears 

only when the vehicle engine speed reached its maximum peak rpm for at least 3 seconds. 

The maximum speed and revolutions per minute was recorded for each gear. Since speed 

is affected by wind, tests were performed in both directions and averaged. Tests took 

place on October 13, 2009 and the recorded wind speed was 11 km/h. 

Table 9 lists the maximum speeds obtained in two separate trials in opposite directions 

for each gear. 

Vmax 

Gear selection 

(km/h) 

A. Gear selection no 1 49.7 

B. Gear selection no 2 78.0 

C. Gear selection no 3 117.0 

D. Gear selection no 4 144.2 

E. Gear selection no 5 138.0 

Table 9: Average Results for Maximum Speed in Each Gear 

During testing, the smart mhd reached an average maximum speed of 144.2 km/h in 

approximately 40 seconds, while operating in 4 th gear. Thus, the smart mhd has the 

capability of meeting and exceeding all minimum speed requirements on public roads in 

Canada. Additionally, the torque and acceleration compare favourably to typical results 

__________________________________________________________________________________ 


in the sub-compact class, and allow for the highway merging and overtaking that most 

Canadians have come to expect from their vehicles. 

Figure 6 below presents the maximum speed and speed in each gear in one direction 

before being averaged. 

160 

Speed (km/h) 

140 

120 

100 

80 

60 

4 th 

3 rd 117 km/h 

2 nd 78 km/ h 

1 st 

14 4 .2 km/ h 

5 th 13 8 km/h 

40 

49.7 km/h 

20 

0 

0 10 20 30 40 50 60 70 80 90 100 

Time (seconds) 

Figure 6: Maximum Speed in Gear, Single Run 

6.3 HANDLING 

6.3.1 Lateral Skid Pad 

The lateral skid pad test was used to determine the maximum speed that the smart mhd 

could achieve in a cornering situation. When a vehicle reaches its cornering limit, it will 

either under-steer or over-steer, losing traction on the curve. When the vehicle has almost 

lost traction, the maximum lateral acceleration is recorded. 

In order to measure vehicle displacement, speed and lateral acceleration, the smart mhd 

was equipped with a combined GPS and accelerometer-based data acquisition system. All 

measurements refer to the vehicle’s centre of gravity. 

Tires were warmed up and conditioned by using a sinusoidal steering pattern at a 

frequency of 1 Hz, a peak steering-wheel angle amplitude corresponding to a peak lateral 

acceleration of 0.5–0.6 g, and a speed of 56 km/h. The vehicle was driven through the 

course four times, performing 10 cycles of sinusoidal steering during each pass. 

__________________________________________________________________________________ 


Testing was performed under the following conditions: 

 

 

 

 

The vehicle was equipped with new tires. 

Tire pressure was adjusted to conform to the manufacturer’s recommendations. 

The vehicle’s weight was adjusted to its lightly loaded condition. 

The skid pad was 61 m in diameter. 

Figure 7: Test Vehicle on Counter-Clockwise Run 

The results presented in Table 10 show that the maximum speed that the vehicle can 

achieve in a cornering situation is 51 km/h. 

Clockwise 

Counter-Clockwise 

Speed (km/h) Stay Inside Corridor? (Yes/No) Speed (km/h) Stay Inside Corridor? (Yes/No) 

50/51 Yes 50/50 Yes 

53/52 Yes 55/51(*) Yes 

62/51(*) Yes 57/51(*) Yes 

53/51(*) No 

*ESC system is activated, reducing speed to 51 km/h 

Table 10: Skid Pad Test Results 

Even when the cruise control is engaged, the maximum speed that the vehicle can 

achieve in a cornering situation, with the electronic stability control (ESC) system turned 

on, is still 51 km/h. In this case, the maximum lateral acceleration is 6.3 m/s 2 , based on a 

peak friction coefficient of 98. The coefficient value is dependent on several factors that 

make it almost impossible to predict the friction forces (magnitude and direction between 

tires and the test surface). This complex phenomenon depends on a tire 

longitudinal/lateral motion and will not be discussed here. 

__________________________________________________________________________________ 


a 1 = 6.3 m/s 2 

Because the ESC system engaged, the vehicle never reached its cornering limit and never 

lost traction. It can therefore be concluded that the ESC system on the smart mhd is 

effective in helping to maintain vehicle stability in a cornering situation and, by 

extension, in most road situations. 

6.3.2 Emergency Lane Change Manoeuvre 

The emergency lane change manoeuvre with obstacle avoidance test was performed, 

based on ISO 3888-2: 2002 Passenger Cars – Test Track for a severe lane change 

manoeuvre. During this test, the vehicle entered the course at a particular speed and the 

throttle was released. The driver then attempted to negotiate the course without striking 

the pylons. The test speed was progressively increased until instability occurred or the 

course could not be negotiated. 

Figure 8: Emergency Lane Change Course 

As illustrated in Figure 8, section 4 of the course was shorter than section 2 by one metre 

in order to achieve maximum lateral acceleration at this area. Tests were performed in 

one direction only. If any pylons were hit, the run was disallowed. 

__________________________________________________________________________________ 


Figure 9: Emergency Lane Change Manoeuvre, Disallowed Run 

Several tests were necessary to determine at which speed the smart mhd was able to 

negotiate all the way through the prescribed course without hitting a pylon. Table 11 lists 

all runs in increasing order, by speed. 

Initial Speed (km/h) 

Pylon Hit? (Yes/No) 

50 No 

55 No 

60 No 

59 No 

63(*) No 

65 No 

67 No 

70(**)/60 Yes 

*First occurrence of electronic stability control (ESC) system engagement 

**ESC controlled vehicle’s behaviour, average speed dropped to 60 km/h 

Table 11: smart fortwo mhd Emergency Lane Change Results 

While there is no pass or fail in terms of speed for emergency lane change manoeuvres, it 

is a fair assessment of the lateral stability of a vehicle. The maximum successful entry 

speed through the course was recorded as 67 km/h. This result is fair compared to other 

vehicles that the eTV program has tested. 

__________________________________________________________________________________ 


10 

8 

Run 50 (km/h): -7.8 m/s2 

Run 70 (km/h): -9.0 (m/s2) 

Lateral Acceleration (m/s 2 ) 

6 

4 

2 

0 

-2 

-4 

-6 

-8 

-10 

0 0,5 1 1,5 2 2,5 3 3,5 4 

Time (seconds) 

Figure 10: Lateral Accelerations Recorded During Emergency Lane Change Manoeuvre 

As seen in Figure 10 above, the maximum lateral acceleration recorded on a successful 

run was 9.0 m/s 2 . 

6.4 NOISE EMISSIONS TESTS 

The smart mhd was tested in accordance with the CMVSS 1106 Noise Emissions Test, 

SAE Recommended Practice J986, Sound Level for Passenger Cars and Light Trucks, 

and SAE Standard J1470, Measurement of Noise Emitted by Accelerating Highway 

Vehicles. In order to measure noise emitted from the engine and exhaust, microphones 

were set up as shown in Figure 11 below. 

__________________________________________________________________________________ 


Figure 11: Noise Emissions Setup 

Testing was performed under the following conditions: 

 

 

The vehicle test weight, including driver and instrumentation, did not exceed the 

vehicle’s curb weight by more than 125 kg; 

For a period of one minute, the vehicle’s engine speed was returned to idle and the 

vehicle’s transmission was set in neutral gear before each run, in order to stabilize the 

initial transmission and exhaust system temperatures. 

The test procedure for the acceleration tests was as follows: 

 

 

 

 

When the vehicle approached a speed of 48 km/h ± 1.2 km/h, the approaching speed 

was stabilized before the acceleration point; 

At the acceleration point (± 1.5 m), as rapidly as it was possible to establish, the 

throttle was opened wide; 

Acceleration continued until the entire vehicle had exited the test zone; 

The sound meter was set to fast dB(A). 

The deceleration tests followed the same procedure as above, with one modification – at 

the deceleration point, the vehicle was returned to its idle position until it was equal to 

one half of the approaching speed or until the entire vehicle had exited the test zone. 

Results from all tests show that the ambient noise levels are within the limits of the 

CMVSS 1106 standards. Due to the logarithmic nature of the decibel scale, a level of 

65 dB is significantly lower than the 93.8 decibel limit. Generally 60 dB is considered to 

be the level of normal human conversation while 90 dB would be the sound generated by 

a typical lawn mower. 

__________________________________________________________________________________ 


The levels measured for the smart mhd are typical for a gasoline powered sub-compact 

vehicle. Most of the noise being generated from the vehicle at these test speeds is due to 

tire and wind resistance, which is acceptable and similar across any vehicle power train 

platform. 

Test Side 

# 

Approaching 

Speed 

(km/h) 

Approaching 

RPM 

End Speed 

(1) 

(km/h) 

RPM max 

(1) 

Noise Level 

dB (A) 

Calibration 

dB (A) 

Right – 1 48 3950 54 4500 67.3 93.8 

Right – 2 48 3950 54 4500 67.2 93.8 

Right – 3 48 3950 54 4500 67.6 93.8 

Right – 4 48 3950 54 4500 67.7 93.8 

Average 54 67.5 

Left – 1 48 3950 54 4500 67.8 93.8 

Left – 2 48 3950 54 4500 67.0 93.8 

Left – 3 48 3950 54 4500 67.1 93.8 

Left – 4 48 3950 54 4500 67.2 93.8 


Results = Highest Average – 2dB 65.5 

Ambient Noise (2) 41.7 

Table 12: External Noise, Approaching 48 km/h 

Results : 

Pass 

Test Side 

# 

Approaching 

Speed 

(km/h) 

Approaching 

RPM 

End Speed 

(1) 

(km/h) 

RPM max 

(1) 

Noise Level 

dB (A) 

Calibration 

dB (A) 

Right – 1 54 4500 44 3600 63.4 93.8 

Right – 2 54 4500 44 3600 63.1 93.8 

Right – 3 54 4500 44 3600 63.6 93.8 

Right – 4 54 4500 44 3600 63.4 93.8 


Left – 1 54 4500 44 3600 64.6 93.8 

Left – 2 54 4500 44 3600 64.5 93.8 

Left – 3 54 4500 44 3600 64.5 93.8 

Left – 4 54 4500 44 3600 64.6 93.8 


Results = Highest Average – 2dB 62.6 

Ambient Noise (2) 41.7 

Table 13: External Noise, Approaching 54 km/h 

Results : 

Pass 

Interior noise emitted from the vehicle was evaluated at different constant speeds in order 

to determine the levels experienced by the driver of the vehicle. It is interesting to note 

that, except for idling, the smart mhd experienced a higher dB within the vehicle than the 

values recorded externally. The interior noise levels, while well below the legal limit, 

were slightly higher than other sub-compact cars evaluated by eTV. 

__________________________________________________________________________________ 


Test # and Targeted Calibration Noise Level Transmission Selection 

Test Speed 

dB (A) 

dB (A) 

Idle 93.8 49.3 Neutral 

Ambient Temperature 37.0 Engine Off 

Full Acceleration – 1 93.8 80.1 26 sec. – 138 km/h – redline 

Full Acceleration – 2 93.8 79.9 26 sec. – 138 km/h – redline 

Full acceleration – 3 93.8 79.7 26 sec. – 138 km/h –redline 

Average 79.9 26 sec. – 138 km/h –redline 

110 km/h – 1 93.8 76.5 Overdrive 

110 km/h – 2 93.8 77.3 Overdrive 

110 km/h – 3 93.8 77.3 Overdrive 

Average 77.0 Overdrive 

100 km/h – 1 93.8 77.9 Overdrive 

100 km/h – 2 93.8 76.2 Overdrive 

100 km/h – 3 93.8 75.7 Overdrive 

Average 76.6 Overdrive 

80 km/h – 1 93.8 75.6 4 th 

80 km/h – 2 93.8 75.7 4 th 

80 km/h – 3 93.8 75.7 4 th 

Average 75.7 4 th 

50 km/h – 1 93.8 72.8 3 rd 

50 km/h – 2 93.8 72.2 3 rd 

50 km/h – 3 93.8 71.0 3 rd 

Average 72.0 3 rd 

Table 14: Internal Noise 

6.5 BRAKING 

Testing was performed in accordance with the procedures set out in CMVSS 135 - Light 

Vehicle Brake Systems. The results are presented in Table 15. 

Test Description 

Pass / Fail 

Cold Effectiveness 

Pass 

High Speed Effectiveness 

Pass 

Stops with Engine Off 

Pass 

Failed Antilock 

Pass 

Hydraulic Circuit Failure 

Pass 

Power Brake Unit Failure 

Pass 

Parking Brake 

Pass 

Hot Performance 

Pass 

Recovery Performance 

Pass 

Table 15: Brake Test Results Summary 

The smart mhd is compliant with all aspects of the CMVSS 135 standard. Figure 12 

below displays a sample of the stopping distances at two compliance speeds. The 

performance of the smart mhd at both speeds is exemplary. It should be noted that it is 

typical for all vehicles to exceed the high-speed braking standard by a greater relative 

__________________________________________________________________________________ 


amount than the low-speed braking standard. This is partially due to the difficulty in 

applying maximum braking pressure at the start of the brake test. 

30 m 40 m 50 m 60 m 70 m 80 m 90 m 100 m 

110 m 120 m 

46.26 m 

at 100kph 

(Dry Conditions) 

57.42 m 

at high speed 

112kph 


70.0 m 

Regulated 

braking 

limit at 100kph 


96.17 m 

Regulated 

braking 

limit at 112kph 


Figure 12: smart mhd Braking Performance 

6.6 SUMMARY REMARKS REGARDING DYNAMIC TESTING 

Overall, the dynamic test results show that the smart mhd meets the relevant Canadian 

standards. All aspects of its handling and performance were either good, pass or 

acceptable relative to the sub-compact class, and its dynamic performance was similar to 

that of market competitors in its class. In addition, the vehicle met all aspects of CMVSS 

noise and braking standards. 

7.0 PHASE III - ON-ROAD EVALUATIONS 

The eTV engineering team and Transport Canada staff evaluated the smart mhd on the 

streets of Ottawa, Ontario. Drivers were asked fill-in a short two-page questionnaire and 

provide comments on any aspect of the smart’s handling, performance or design. 

Evaluators reported that they were comfortable with the idle start-stop system, even in 

heavy city traffic. Some users noticed a slight vibration as the vehicle began to restart and 

noticed that the instrument panel lighting would dim slightly upon restarting. Most users 

were interested in exploring further the fact that this technology could be included in the 

purchase price of a vehicle for about $700 to $1000. With regards to general 

performance and handling several evaluators noted “jerky” shifting of the transmission as 

an issue. 

Some users wondered if turning off an engine not equipped with an idle start-stop system 

could offer the same savings. While similar savings might be obtained by turning off the 

engine in a regular vehicle, it is not really designed for multiple restarts and could 

damage the engine. The smart mhd’s engine, on the other hand, is specifically designed 

to handle multiple restarts. As well, the ECU monitors the state of the battery. When too 

many restarts occur in a short period and/or the accessory load demands on the battery 

approach its cut-off voltage, the smart mhd remains in eco-mode but shifts to standby as 

it recharges the battery, thus preventing any chance that the engine will shut off and not 

be able to restart. 

__________________________________________________________________________________ 


The eTV fleet includes both a Canadian-compliant smart fortwo and the European smart 

mhd, providing an opportunity to compare the fuel consumption for the two vehicles on 

the mileage accumulation route. The route is a pre-determined path through the city that 

includes approximately 60 km of city driving and 28 km of highway driving. The same 

driver drove vehicles at the same time of the year. In the case of the smart mhd, the ecomode 

was engaged (ON) for the duration of the accumulation. 

Beginning with a full tank of fuel, the driver repeated the route until 3,500 km had been 

accumulated on each of the two vehicles. At each fuel fill-up, the mileage and the 

amount of fuel were recorded. 

Real-World Fuel Consumption (L/100km) 

Total Consumption 

City Savings 

Standard smart 5.18 

smart mhd 4.68 9.7% 

Table 16: Real-world Fuel Consumption Results 

As can be seen from the real-world data presented in Table 16, a significant fuel savings 

(9.7 %) was obtained when using the idle start-stop system. The data is consistent and 

correlates well with the fuel consumption testing results for city driving cycles, as 

reported in Section 5 of this report. Considering all of the possible variables in the real 

world, such as traffic, time stopped at lights, varying speeds, wind and weather, a 

noticeable savings accrued that is outside of the margin of error for this idle start-stop 

system. 

Assuming 20,000 km of annual city driving, the smart mhd could offer upwards of 240 

kg of CO 2 savings 6 or 1.2 kg CO 2 per 100 km when compared to a smart not equipped 

with the idle start-stop system. 

8.0 CONCLUSIONS 

The eTV program selected the smart fortwo micro hybrid drive (mhd) for testing and 

evaluation largely because of its idle start-stop system. The testing program was 

designed to assess the vehicle’s idle start-stop technology as well as its fuel consumption, 

exhaust emissions and overall handling. 

We found that, in all testing cycles, the use of idle start-stop offers considerable savings 

in fuel consumption in city driving, ranging from a 4% savings in 2-cycle testing through 

to a savings of 11.5% with the New York City Cycle. Reduced fuel consumption with 

the idle start-stop technology results in reduced CO 2 emissions. In fact, with the idle 

start-stop (eco-mode) turned ON, the smart mhd obtained a value of 109 g/km, which is 

29% less than the current best performers in the sub-compact class and a 55% 

improvement over all models within its class. With regard to non-CO 2 exhaust 

6 Calculation based on 10,000 km of city driving, assuming 2.4 kg CO 2 per litre of gasoline 

__________________________________________________________________________________ 


emissions, the 2009 smart mhd meets the Euro V emissions standards for which it was 

designed and is well below the Tier 2, Bin 5 standards in effect in Canada. 

The eTV program investigated whether idle start-stop technologies had an impact on 

performance. During cold-cell testing, the eTV program found that the smart mhd is able 

to operate between -7C and 40C, with varying uses of the auxiliary systems. However, 

below -7C, by design, the vehicle did not allow the eco-mode to engage and turn off the 

engine when idling, despite acceptable battery voltage levels. Thus, in Canada, some of 

the system’s fuel saving capacity will be lost during cold winter months. Overall, 

handling and performance of the vehicle were not affected by the anti-idling technology. 

As such, dynamic performance would not pose a barrier to its inclusion in the fleet of 

sub-compact vehicles in Canada. 

9.0 WHAT DOES THIS MEAN FOR CANADIANS? 

The real-world data obtained through driver evaluations and testing in relation to a smart 

without anti-idling technology confirms that a significant fuel savings can be obtained 

when using the idle start-stop system. The data is consistent and correlates well with the 

fuel consumption testing results for city driving cycles, for all of the possible variables in 

the real world, such as traffic, time stopped at lights, varying speeds, wind and weather. 

However, public opinion research has generally established that fuel consumption and 

vehicle emissions have not traditionally been of primary importance to the Canadian 

consumer when shopping for a new vehicle. One of the principle barriers to the 

introduction of advanced gasoline technologies, such as the idle start-stop system, is 

overcoming the consumer’s desire to minimize the initial purchase price (or ‘sticker 

shock’), often at the expense of longer-term operating costs and environmental impacts. 

Conversely, according to a recent study by the National Academy of Sciences 7 innovative 

technologies that improve fuel efficiency often increase the initial purchase price of a 

vehicle. In the case of the idle start-stop technology, it could increase the purchase price 

by $700 to $1000. When confronted with the choice of paying more for advanced 

vehicle technologies such as idle stop-start, consumers often opt for a lower initial 

purchase price, unaware of the potential savings that the technology might offer. 

In addition, fuel consumption test procedures and vehicle ratings are not designed to 

accommodate many of the advanced technologies and, as such, may under-estimate their 

potential real-world benefits. The results outlined in this report support that point, since 

the 2-cycle tests under-represented the fuel savings obtained both in the New York City 

Cycle and in real-world driving. In these situations, not only does the vehicle cost more, 

but also there appears to be little improvement in the vehicle’s published fuel 

consumption ratings – a situation that compounds existing consumer barriers. 

7 National Academy of Sciences. 2010. Assessment of Technologies for Improving Light-Duty Vehicle 

Fuel Economy. 

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smart fortwo mhd test results - Transports Canada

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