Subaru Forester PZEV - Advanced Gasoline
Subaru Forester PZEV - Advanced Gasoline
1 Subaru Forester PZEV Advanced Gasoline Partial Zero Emission Vehicle Test Results Report July 2011
2 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, 2011-2012
3 Table of Contents EXECUTIVE SUMMARY . 4 1 INTRODUCTION . 8 2 TESTING PROGRAM . 9 3 TESTING LOCATIONS . 9 4 VEHICLE OVERVIEW . 10 5 PHASE I - LABORATORY FUEL CONSUMPTION, EVAPORATIVE AND EXHAUST EMISSION TESTING . 11 5.1 RESULTS . 12 5.1.1 2-Cycle Fuel Consumption Results .
14 5.1.2 5-Cycle Fuel Consumption Results . 15 5.1.3 Emissions Results . 15 5.1.4 Evaporative Emission Tests . 17 6 PHASE II – DYNAMIC TESTING . 18 6.1 ACCELERATION EVALUATION . 19 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 . 22 6.4 NOISE EMISSION TESTS . 24 6.5 BRAKING . 27 6.6 SUMMARY REMARKS REGARDING DYNAMIC TESTING . 28 7 PHASE III - ON-ROAD EVALUATIONS . 28 7.1 OPERATION AND PERFORMANCE . 29 7.2 COMFORT AND CONTROLS . 29 7.3 PZEV PERFORMANCE . 29 8 CONCLUSIONS . 31
4 EXECUTIVE SUMMARY The Subaru Forester PZEV is a Partial Zero Emission Vehicle (PZEV) and as such is one of the least polluting vehicles in the Canadian light-duty fleet. PZEV is a designation under the California Air Resources Board (CARB) Phase Two Low Emission Vehicles (LEV II) regulations. According to CARB’s regulations, the PZEV designation indicates a vehicle that:
Satisfies the strictest emission requirements applicable to internal combustion engine vehicles;
Achieves near-zero evaporative emissions from the fuel system (hence the name “Partial Zero Emission Vehicle”); and
Is defended by a 15 year 150,000 mile (240,000 km) warranty assuring that the PZEV emission standard is satisfied within the time and mileage limits.
In Canada, the emission regulations are different from CARB and do not require the 15 year warranty, but all other performance aspects of the PZEV requirement are retained in the Canadian offering of the Subaru PZEV.
The PZEV emission category is roughly equivalent to the second cleanest category (Tier 2 Bin 2) of the On-Road Vehicle and Engine Emission Regulations, part of the Canadian Environmental Protection Act (CEPA), 1999. The only cleaner emission category is zero emissions. The vehicle creates about 90% fewer emissions than the current Canadian emission requirement limits. The PZEV designation also indicates near-zero evaporative emissions. “Evaporative emissions" means hydrocarbons emitted into the atmosphere from a vehicle, other than exhaust emissions and crankcase emissions. These emissions may escape while the engine is not operating.
PZEV vehicles emit significantly less evaporative emissions than the Canadian requirement limit.
The eTV program selected the Subaru Forester PZEV for testing and evaluation because of its PZEV designation. Evaporative emissions not only reduce air quality and contribute to human health hazards in dense urban areas, but also affect the greenhouse gas (GHG) impact of vehicles from the direct evaporation of unused fuel into the atmosphere. The global warming potential (GWP) of gasoline (essentially non-methane hydrocarbons) versus CO2 is 12. This means that for every gram of gasoline that evaporates into the atmosphere the equivalent mass of CO2 to achieve the same overall warming effect is 12 grams of CO2.
PZEV systems are relatively rare within the Canadian market. There are no regulatory requirements for them to be available. Also, there is no government supported method to recognize these lower-emission vehicles Canada, unlike in California, where the PZEV emblem indicates compliance with stricter emission standards. The Subaru Forester PZEV was deemed an appropriate vehicle for inclusion in the eTV program. In acquiring the Subaru Forester PZEV, the eTV program wanted to quantify the reductions in GHG and air pollution due to cleaner exhaust emissions and evaporative emissions that would result from such a vehicle, as well as evaluating the performance under a variety of
5 Canadian climatic conditions, particularly in city driving and in cold weather. The vehicle was tested and evaluated over three phases: laboratory fuel consumption, evaporative 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
2-cycle testing, the method used to determine fuel consumption according to Canadian regulations, relies on two simulated drive patterns, or ‘cycles’, representing city driving and highway driving. The resulting fuel consumption values obtained by eTV testing are: o 11.0 L/100 km for the city o 7.5 L/100 km for the highway
The fuel consumption values published in Natural Resources Canada’s Fuel Consumption Guide are: o 10.4 L/100 km for the city o 7.7 L/100 km for the highway It is not uncommon for tests to achieve results that differ by up to 1.0 L/100km when the same testing is performed by a different lab on the same model of vehicle.
So the 2-cycle eTV test results, although not exactly the same as the published fuel consumption values, are not in conflict with the published values.
5-cycle testing, the method used by United States Environmental Protection Agency (EPA) to determine fuel consumption, utilizes cycles that simulate city driving, highway driving, aggressive driving style, city driving in cold temperature (at -7 ºC), and driving with an electrical load due to air conditioning. This test method typically results in fuel consumption values that are 10 to 20% higher than those determined using the 2-cycle method. eTV’s results using this test method are: o 13.0 L/100 km for the city o 9.4 L/100 km for the highway CO2 emissions In combined city and highway testing, the Subaru PZEV obtained an adjusted value of 217 g/km, which is lower than the sales-weighted national average CO2 emissions of 236 g/km for all AWD and 4x4 special purpose vehicles in Canada for the 2010 model year.
The CO2 emissions of the Subaru Forester PZEV are an 8% improvement than the stated average.
6 Exhaust Emissions With regard to non-CO2 exhaust emissions, the 2010 Subaru PZEV surpasses the EPA Tier 2, Bin 5 emission category for which manufacturer’s fleet average NOx emissions must comply with. The maximum allowable emission category of Tier 2, Bin 8 is easily satisfied. eTV’s testing showed that it surpasses all but one of the emission criteria needed for a SULEV/PZEV designation. Results/Limits CO Non-Methane Organic Gas (NMOG) Formaldehyde (HCHO) NOx CO2 Subaru Forester PZEV 0.16 0.023 0.001 0.01 349 CARB – PZEV standard 1.0 0.010 0.008 0.02 - Standard – Tier 2 Bin 5 3.4 0.075 0.015 0.05 - Relative to the CARB PZEV standard for which the Subaru Forester PZEV was designed to meet, the results indicate relatively low CO, NOx, and formaldehyde emissions but higher non-methane organic gas emissions.
It is possible that a retesting of the vehicle would result in a lower non-methane organic gas emission measurement that would satisfy the CARB standard1 .
Evaporative Emission Results The Subaru PZEV satisfies the CARB evaporative emission test standards of 0.35 grams per test for the two-day evaporative emission test with a value of 0.20 grams per test. This results in 0.40 grams fewer emissions than conventional nonPZEV vehicle emissions of 0.60 grams per test. Dynamic Performance Overall, handling and performance were acceptable relative to the special purpose class.
The Subaru PZEV reached an average maximum speed of 144.2 km/h in approximately 40 seconds.
The maximum lateral acceleration was 0.64 G (6.3 m/s2 ) for a 200 ft (61 m) turning circle.
External and internal noise levels were well below the limits set out in the Canada Motor Vehicle Safety Standards (CMVSS).
Braking is compliant with all aspects of the CMVSS 135 standard.
Driver Evaluations Of the 15 evaluations completed on the Subaru Forester PZEV, 100% of respondents did not notice any performance difference between the PZEV and a regular gasoline car. This demonstrates how this technology can be implemented in vehicles without having an impact on the consumer’s experience of the technology. It is also notable that 67% of respondents did not have prior knowledge of the more stringent emission standard that PZEVs comply with. Dissemination of the valuable benefits of PZEV technology to potential consumers is an important part of introducing such a technology into the market.
1 The tests were conducted on a four wheel drive dynamometer during dyno control system development. The test cell was in the process of refining upgraded components, and had not yet performed a correlation program to verify the accuracy of the test results.
7 Barriers to the Introduction of PZEV Technologies into the Canadian Market Public opinion research suggests that exhaust emissions have not traditionally been of primary importance to the Canadian consumer when shopping for a new vehicle2 . One of the principle barriers to the introduction of advanced gasoline technologies, such as PZEV technologies, is overcoming the consumer’s desire to minimize the initial purchase price (or ‘sticker shock’) of a new vehicle. In contrast to fuel savings, lower emissions do not present a savings opportunity for the owner. They are simply less polluting to the environment.
The kind of testing that eTV has undertaken on PZEV technology provides information to evaluate the benefits of this technology in Canada. There is no current specific regulatory standard that requires or provides incentive for the adoption of the technology in Canada, but there are evident benefits in air pollution reduction attributable to PZEV technology. 2 Pollution Probe. 2008. Barriers to Consumer Purchasing of More Highly Fuel-Efficient Vehicles: A Background Paper.
8 1 INTRODUCTION Partial Zero Emission Vehicle (PZEV) is a category within the California Air Resources Board (CARB) Phase 2 Low Emission Vehicle (LEV II) emission regulations.
The PZEV designation indicates a vehicle that satisfies the strictest emission requirements applicable to internal combustion engine vehicles, and also achieves near-zero evaporative emissions from the fuel system and, in addition, requires a 15 year 150,000 mile (240,000 km) warranty assuring that the emission standard is met within these limits. In Canada, the emission regulations are different from CARB and do not require the 15 year warranty, but all other performance aspects of the PZEV requirement are retained in the Canadian offering of the Subaru PZEV. A PZEV vehicle is approximately 90% cleaner than the Canadian exhaust emission limits for new vehicles.
Evaporative emissions for CARB PZEV vehicles are limited to 0.35 grams per day (according to standardized testing). Current Canadian evaporative emission standards allow for up to 0.50 grams per day; however manufacturers need only meet a fleet average in the Canadian emission standard whereas any vehicle with a PZEV designation must satisfy the 0.35 gram limit. CARB emission standards have historically been more stringent than Canadian and US Environmental Protection Agency (EPA) emission standards and have often been the driver towards lower emissions within North America. Subaru introduced PZEV models (Legacy PZEV, Forester PZEV, and Outback PZEV) into Canada in late 2009, as a 2010 model year vehicles.
Currently, Subaru models are sold in Canada and the United States, with both the PZEV and non-PZEV designations. The Forester is available as a PZEV model in all Canadian provinces as well as the 50 US states. Typically manufacturers only offer PZEV vehicles in states that adopt CARB emission requirements.
Working in partnership with Subaru, the eTV program selected the Subaru Forester PZEV for testing because it meets CARB standards. Evaporative emissions not only reduce air quality and contribute to human health hazards, particularly in dense urban areas, but also affect the greenhouse gas (GHG) impact of vehicles from the direct evaporation of unused fuel into the atmosphere. The global warming potential (GWP) of gasoline (essentially non-methane hydrocarbons) versus CO2 is 12. This means that for every gram of gasoline that evaporates into the atmosphere the equivalent mass of CO2 to achieve the same overall warming effect is 12 grams of CO2.
Specifically, PZEV technology reduces the following criteria air contaminants: - Non-methane organic compounds (NMOG), this include hydrocarbons - Nitrogen oxides (NOx) - Particulate matter (PM) - Carbon monoxide (CO) - Formaldehyde (HCHO)
9 In the Subaru Forester PZEV, the fuel injectors, air-intake system, catalytic converter and engine control module have been modified in order to achieve the CARB PZEV designation. Any vehicle with a PZEV designation emits significantly lower exhaust emissions and evaporative emissions than a conventional non-PZEV vehicle.
Summed over the entire Canadian fleet, for a single year of new vehicles sales, PZEV designated vehicles could reduce evaporative emissions in Canada by over 50,000 litres. When considering the greenhouse gas effect, this is equivalent to about half a million kilograms of CO2 in warming potential.
2 TESTING PROGRAM The testing program was designed to provide a fair assessment of the PZEV technology found on the Subaru Forester PZEV, in terms of fuel consumption, exhaust and evaporative emissions, and overall handling. The suggested tests were based on practices used by the Company Average Fuel Consumption (CAFC), the U.S. Environmental Protection Agency, the U.S. Department of Transportation, the International Organization for Standardization and the Society of Automotive Engineers (see Subaru Forester PZEV test plan for details).
The Subaru Forester PZEV was evaluated over three distinct phases:
Phase I - Laboratory fuel consumption, evaporative and exhaust emission testing
Phase II - Dynamic track testing
Phase III - On-road evaluations Together, these various phases were designed to realistically assess the Subaru PZEV’s overall performance in Canadian conditions.
3 TESTING LOCATIONS Phase I testing was performed at Environment Canada’s Emissions Research and Measurements Section (ERMS) 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. 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
10 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 performed by Transport Canada staff. A total of 15 evaluations were performed, in which participants tried the vehicle on public roads and filled out a questionnaire. 4 VEHICLE OVERVIEW The Subaru PZEV is classified as a special purpose vehicle. The PZEV, or Partial Zero Emission Vehicle, designation was created by the California Air Resources Board (CARB) as a requirement for their Low Emission Vehicle (LEV II) standards.
Although PZEV vehicles are required to be sold in California and other states which have adopted the CARB LEV2 standard, Subaru has made PZEV designated vehicles available throughout the United States and Canada. As of the time of testing, Subaru is the only major vehicle brand selling PZEV designated vehicles in Canada. Table 1 lists the specifications of the vehicle tested. Table 1: Specifications for the Subaru PZEV Weight 1,500 kg Drive Type Symmetrical all-wheel drive Length 4.56 m Engine 2.5 L SOHC, 16-valve, horizontally opposed 4- cylinder engine Width 1.78 m Transmission 4-speed automatic Height 1.70 m Torque 230 Nm / 170 lb-ft @ 4,500 rpm Seating 5 Power 127 kW / 170 hp @ 5,800 rpm Fuel Type Gasoline (regular unleaded) Fuel Efficiency* City Highway 10.4 L/100 km 7.7 L/100 km Displacement 2,500 cm3 Fuel Tank Capacity 64 L Acceleration 0-100km/h in 10 seconds Driving Range 700 km CO2 Emissions 103 g/km Brakes (f/r) Ventilated Discs / Solid Discs Air Pollution Score 9.5 / 10 Drag Coefficient 0.36 *Canadian label value, published in Natural Resource Canada’s 2010 Fuel Consumption Guide The following technologies modifications are what allow Subaru to achieve a PZEV designation with the Forester: Fuel Injectors: The fuel injectors on a Subaru PZEVs close tighter than conventional injectors.
This reduces leakage and evaporative emissions into the intake manifold. Catalytic Converter & Engine Control Module: The catalytic converter in the Subaru Forester is a large (greater surface area) converter containing a greater amount of precious metals, resulting in lower emissions than traditional size catalytic converters. In addition the engine control module retards ignition timing at cold start up in order to
11 drive up exhaust temperatures and heat the catalytic converter sooner. This allows the converter to reduce emissions faster than vehicles not employing this technology. Dual Filtration Air-Intake System: In most conventional vehicles unburnt gas fumes can escape through the air intake filter and assembly. In a Subaru PZEV the air-intake system includes a carbon canister that captures these emissions before they make it to the atmosphere. Figure 1: Subaru Forester PZEV 5 PHASE I - LABORATORY FUEL CONSUMPTION, EVAPORATIVE AND EXHAUST EMISSION TESTING More than 3,500 kilometres of vehicle and engine use were accumulated on the Subaru Forester PZEV, in keeping with the On-Road Vehicle and Engine Emission Regulations of the Canadian Environmental Protection Act (CEPA), 1999.
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 soaked3 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 emission and fuel consumption evaluations.
Emission and fuel consumption tests were performed as per the regulation procedures. Evaluations were performed over the six duty cycles listed in Table 2. In addition, 3 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.
12 evaporative emission analysis was performed over both the single hot-soak and two-day evaporative emission tests. Table 2: Chassis Dynamometer Test Schedule Test Parameter Testing Standard Number of Tests (Cell Temperature) Location Urban Driving U.S.
FTP-75 4 (25°C) ERMS (Ottawa, ON) Cold Test U.S. FTP-72 2 (-7°C) ERMS (Ottawa, ON) Aggressive Driving US06 (SFTP) 2 (25°C) ERMS (Ottawa, ON) Highway Driving U.S. HWFET 4 (25°C) ERMS (Ottawa, ON) Electrical Load US SC03 2 (25°C) ERMS (Ottawa, ON) Stop-and-Go Driving US NYCC 4 (25°C) ERMS (Ottawa, ON) The vehicle was mounted on a chassis dynamometer. A chassis dynamometer allows the vehicle’s drive wheel to turn while the vehicle is stationary, and provides a resistance that is equivalent to what the vehicle would experience travelling on actual roads (essentially a treadmill designed for automobiles).
ERMS collected and analyzed exhaust emissions for each of the duty cycles listed in Table 2. The emissions data were analyzed for: - Non-methane organic compounds (NMOG), this include hydrocarbons - Nitrogen oxides (NOx) - Carbon monoxide (CO) - Formaldehyde (HCHO) 5.1 Results Two methods were used to estimate the fuel consumption of the Subaru Forester PZEV:
The 2-cycle method, which utilizes simulated drive patterns or ‘cycles’ representing city driving and highway driving, is the method used to determine fuel consumption values published by Natural Resources Canada.
The 5-cycle method utilizes cycles that simulate city driving, highway driving, aggressive driving style, city driving in cold temperature (at -7 ºC), and driving with an electrical load due to air conditioning.
The United States EPA uses this method to determine fuel consumption.
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 result of the urban driving cycle (U.S. FTP-75) and the highway duty cycle (U.S. HWFET). Advertised fuel consumption, as published by Natural Resources Canada in the annual Canadian Fuel Consumption Guide, is obtained by adjusting the measured fuel consumption upward 10% and 15% respectively for the
13 city and highway cycles to account for “real-world” differences between the way vehicles are driven on the road and over the test cycles.
Combined city and highway fuel consumption is obtained using a ratio of 55% city and 45% highway. The 5-cycle test method supplements the Canadian 2-cycle test method by taking into account additional factors that affect fuel consumption but are not in the current Canadian 2-cycle standard. The U.S. EPA began to implement 5-cycle testing in 2006, and started publishing fuel consumption results according to the 5-cycle test procedure for model year 2008 vehicles.
The 5-cycle method includes testing over a wider range of driving patterns and temperature conditions than those tested under the current Canadian 2-cycle standard. For example, in the real world, vehicles are often driven more aggressively, at higher speeds and with greater rates of acceleration. These conditions place a greater demand on the engine than existing city and highway test cycles account for. 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 on a fairly regular basis. The current 2-cycle testing is conducted between 20°C and 30°C. The U.S. FTP-72 cold test cycle, conducted at 20°F (-7°C), is used to reflect the effect on fuel consumption when starting and operating an engine at lower temperatures. Fuel consumption values derived from either the 2-cycle or 5-cycle method have merit when used to compare the fuel consumption of one vehicle to that of another. However, comparisons are only valid when the method for obtaining the fuel consumption value is consistent.
For example, a fuel consumption value derived from the 2-cycle method should only be compared to other fuel consumption values derived from the 2-cycle method. Because it takes other factors into account that typically increase fuel consumption the 5-cycle method usually yields fuel consumption values that are approximately 10 to 20% higher than the advertised 2-cycle fuel consumption value for the same make and model. In general, the 5-cycle method may better represent the fuel consumption that can be expected in real world driving, but accurate forecasting of fuel consumption is impossible in practice due to the many unpredictable factors that affect driving efficiency.
Figure 2 shows a schematic of the process that is used to determine the advertised or ‘label’ fuel consumption values for both 2-cycle and 5-cycle testing.
14 Figure 2: Schematic Diagram of the Process for Calculating Fuel Consumption Using the 2-Cycle Method and the 5-Cycle Method 5.1.1 2-Cycle Fuel Consumption Results The Subaru Forester PZEV was tested against the FTP-75 city cycle and the HWFET highway cycle according to current Canadian standards for fuel consumption testing. The results for the measured fuel consumption and advertised fuel consumption values determined by eTV, as well as the published Canadian fuel consumption label value are shown in Table 3.
Table 3: 2-Cycle Fuel Consumption Values 2- Cycle Fuel Consumption (L/100km) City Highway Combined eTV Measured Fuel Consumption 10.0 6.5 8.4 eTV-Derived Advertised ‘Label’ Fuel Consumption 11.0 7.5 9.4 Actual Published Fuel Consumption* 10.4 7.7 9.2 *As published in Natural Resources Canada’s 2010 Fuel Consumption Guide It is not uncommon for tests to achieve results that differ by up to 1.0 L/100km when the same testing is performed by a different lab on the same model of vehicle. The measured 2-cycle combined fuel consumption value of 8.4 L/100 km is slightly better than the estimated fleet average for model year 2010 of 8.6 L/100 km, and it is
15 more than 15% below the Company Average Fuel Consumption (CAFC) standard of 10.0 L/100km. Currently, CAFC targets are voluntarily met by manufacturers, but Environment Canada intends to align with the United States’ plans to regulate GHG emissions and, effectively, fuel consumption. The Canadian GHG emission regulations proposal is the Passenger Automobile and Light Truck Greenhouse Gas Emission Regulations, published on October 13, 2010, in Part 2 of the Canada Gazette. 5.1.2 5-Cycle Fuel Consumption Results Table 4 shows the 5-cycle fuel consumption values determined by eTV compared to the fuel consumption published by the United States EPA.
Table 4: 5-Cycle Fuel Consumption Values 5-Cycle Fuel Consumption (L/100km) City Highway Combined eTV Test Result 13.0 9.4 11.4 Published US EPA value 11.8 9.0 10.7 Difference 10% 5% 7% Although these fuel consumption values are higher than those obtained during the 2-cycle testing, the 5-cycle testing values may provide a more accurate representation of what a driver can expect in terms of real-world fuel consumption. When compared against the advertised city and highway values determined by eTV for the 2-cycle calculation, the 5- cycle fuel consumption values eTV obtained are 18% and 25% higher, respectively.
The values achieved for eTV 5-cycle testing are 10%, 5% and 7% higher than the reported US 5-cycle label values. It is important to note that it is not unusual for test values for an individual vehicle to be up to 10% higher than the values tested by the EPA or reported by manufacturers to the EPA.
5.1.3 Emissions Results The results of the city and highway test cycles offer an advertised combined CO2 emissions value of 217 g/km (349 g/mile). When compared to the sales-weighted national average CO2 emissions of 236 g/km (380 g/mile) for all AWD and 4x4 special purpose vehicles in Canada for the 2010 model year, the emissions of the Subaru Forester PZEV is an 8% improvement. Therefore, for consumers requiring the capabilities of a vehicle in this category, the Subaru has lower than average GHG emissions, for a vehicle of this category, as well as low criteria air contaminant emissions as indicated by the PZEV designation.
Table 5 summarizes the current EPA emission standard for non-CO2 emissions, known as the Tier 2 emission standard, and the CARB LEV II emission standard. The Canadian
16 emission regulations adopt the EPA set of emission standards, which categorize emission limits into Bins 1 through 11. Light-Duty Vehicles (LDV) must satisfy Bin 8 or lower. The Subaru Forester PZEV is actually designated as a special purpose vehicle under Canadian regulations, which makes it a Light Light-Duty Truck (LLDT) according to the emission regulations, so it must satisfy Bin 9 or lower.
The air pollution score in the right-most column is used by the EPA to designate vehicles’ emission performance in a convenient and understandable way, by assigning a numbered ‘grade’ out of 10 (10/10 being ideal).
Table 5: Summary of EPA and CARB Vehicle Emission Standards 4 4 Source: http://www.epa.gov/greenvehicles/Aboutratings.do (obtained 04/03/2011)
17 With regard to non-CO2 exhaust emissions, the 2010 Subaru PZEV surpasses the Tier 2 Bin 5 emission category with which manufacturer’s fleet average NOx emissions must comply with. The maximum allowable emission requirement that must be satisfied by light-duty vehicles in Canada, Tier 2 Bin 8, is easily satisfied. Testing showed that it surpasses all but one of the emission criteria needed for a SULEV/PZEV designation.
Table 6 shows the measured exhaust emissions and the emission limits of standards. Table 6: Measured Exhaust Emissions vs. Standards (g/mile) Results/Limits CO Non-Methane Organic Gas (NMOG) Formaldehyde (HCHO) NOx CO2 Subaru Forester PZEV 0.16 0.023 0.001 0.01 349 Standard – Tier 2 Bin 5 3.4 0.075 0.015 0.05 - CARB – PZEV standard 1.0 0.010 0.008 0.02 - Relative to the CARB PZEV standard for which the Subaru Forester PZEV was designed to meet, the results indicate relatively low CO, NOx, and formaldehyde emissions but higher non-methane organic gas emissions. It is possible that a retesting of the vehicle would result in a lower non-methane organic gas emissions measurement that would satisfy the CARB standard5 .
5.1.4 Evaporative Emission Tests Evaporative emissions occur when fuel evaporates from a vehicle. This phenomenon increases as the fuel system increases in temperature either through vehicle operation or rising external temperatures. Evaporative emission regulations set a limit on the total amount of fuel that may evaporate from a vehicle over a given length of time. All evaporative emission tests follow the same basic principles: 1- A carbon canister, designed to capture any emissions for later analysis, is prepped 2- Test fuel is added to the test vehicle 3- The vehicle is prepped through a drive cycle 4- The vehicle is soaked.
5- A hot soak test and diurnal test are performed The test is a known as a SHED test for “sealed housings for evaporative determinations”. The test simulates the temperatures to which a vehicle would be exposed while parked in typical summer conditions. Testing involved preparing and testing the Subaru PZEV as 5 The tests were conducted on a four wheel drive dynamometer during dyno control system development. The test cell was in the process of refining upgraded components, and had not yet performed a correlation program to verify the accuracy of the test results.
18 per Title 40 US CFR Section 86, Subpart M6 .
The SHED measures the total amount of unburnt fuel that evaporates from the test vehicle during the test period. The Canadian ‘two-day + hot soak’ test limit allows up to 0.65 grams of evaporative emissions per test. The CARB ‘two-day test + hot soak limit’ is 0.35 grams per test. Table 7 shows the evaporative emission results measured for the Subaru Forester. Table 7: Evaporative Emission Results and Limits (grams/test) Two Day + hot soak Hot Soak Two Day Total Subaru Forester 0.02 0.18 0.20 Canadian Emission Limit - - 0.65 CARB – PZEV Limit - - 0.35 The Subaru Forester emits 0.45 grams per test less than current Canadian standards of 0.65 grams per test.
As a result, a basic estimate of the number of litres of fuel saved with advanced evaporative emission technologies can be performed.
0.40 grams per 2 days (for summer days)
Roughly 125 warm day/nights per year
Approximately 1.5 million news cars per year sold in Canada Calculation of total annual fuel savings: 0.40 grams/2 days x 125 days x 1.5 million = 37,500 kilograms or 50,000 litres Thus, assuming a best-case scenario, where all new cars entering the Canadian market in a given year meet the PZEV evaporative emission standard, approximately 50,000 litres less gasoline would evaporate into the atmosphere each year in this basic scenario (additional study would be required to validate). Summed over the entire Canadian fleet, for a single year of new vehicles sales, PZEV designated vehicles could reduce evaporative emissions in Canada by over 50,000 litres.
The amount of fuel saved is insignificant from an economic viewpoint, but considering the greenhouse gas effect, this is equivalent to about half a million kilograms of CO2 in warming potential. Also, hydrocarbon emissions are toxic to human health, so there is an air pollution reduction benefit as well.
6 PHASE II – DYNAMIC TESTING 6 The EPA and CARB evaporative emissions tests differ somewhat in the temperature at which the tests are performed. The Subaru Forester PZEV was tested according to the evaporative emission test for Canada, which is the same as the EPA test as listed in the CFR Section 86 Subpart M.
19 The Subaru Forester PZEV 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 an advanced 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. Figure 3 shows an aerial view of the test track. Figure 3: 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).
The Subaru Forester tested was equipped with a 4-speed Sportshift transmission.
Shifting was performed in “manual” mode at what was determined by the driver 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.
20 Table 8: Average Speed Results for Specified Distances Distance Speed ( km/hr ) 1/4 mile ( 402.3 m) 126 1,000 m 163 The acceleration compares favourably to typical results in the special purpose class of vehicles, and allow for the highway merging and overtaking that most Canadians have come to expect from their vehicles. 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 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 21, 2009 and the recorded wind speed was 14 km/h.
Table 9 lists the maximum speeds obtained experimentally in two separate trials in opposite directions for each gear. Table 9: Average Results for Maximum Speed in Each Gear Gear selection Maximum Speed (km/h) A. Gear selection no 1 59.1 B. Gear selection no 2 111.2 C. Gear selection no 3 169.9 D. Gear selection no 4 174.4 During testing, the Subaru PZEV reached an average maximum speed of 174 km/h in approximately 40 seconds, while operating in 4th gear. The Subaru PZEV is easily capable of meeting and exceeding all minimum speed requirements on public roads in Canada.
Figure 4 presents the maximum speed and speed in each gear in one direction before being averaged.
21 Figure 4: Maximum Speed in Gear, Single Run 6.3 Handling 6.3.1 Lateral Skid Pad The skid pad test was used to evaluate the steady-state road holding ability and lateral stability of the vehicle. The lateral skid pad test determines the maximum lateral acceleration that the Subaru Forester PZEV can achieve in a cornering situation. The skid pad is set up by marking out a 200 foot (61 metre) diameter circle on asphalt, using pylons. The vehicle must then reach the maximum speed possible while driving along the inside of the perimeter of the circle, without exiting the circle area or striking the pylons.
When a vehicle reaches its cornering limit, it will lose traction on the curve. The vehicle is driven in circles within a 200 foot (61 metre) diameter while maintaining the maximum speed possible. The lateral acceleration is measured at the vehicle’s cornering limit, as it begins losing traction on the curve.
In order to measure vehicle displacement, speed and lateral acceleration, the Subaru PZEV was equipped with a combined GPS and accelerometer-based data acquisition system. All measurements refer to the vehicle’s centre of gravity.
22 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 5 shows a picture of the vehicle navigating the skid pad in a counter-clockwise direction. Figure 5: Test Vehicle on Counter-Clockwise Run The results presented in Table 11 show that the maximum speed that the vehicle can achieve in a 61m diameter cornering situation is 58 km/h. Table 10: Skid Pad Test Results Clockwise Counter-Clockwise Speed (km/h) Stay Inside Corridor? (Yes/No) Speed (km/h) Stay Inside Corridor? (Yes/No) 50 Yes 50 Yes 55 Yes 55 Yes 58 No 55 Yes 56 Yes 58 Yes 58 Yes 60 No The maximum speed that the vehicle can achieve in this cornering situation is 58 km/h. In this case, the measured maximum lateral acceleration is 0.81 G (7.9 m/s2 ).
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
23 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. As illustrated in Figure 6, 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 6: Emergency Lane Change Course Figure 7 shows a picture of the vehicle performing the emergency lane-change manoeuvre during a run where a pylon was struck.
Figure 7: Emergency Lane Change Manoeuvre, Disallowed Run Several tests were necessary to determine at which speed the Subaru PZEV 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.
24 Table 11: Subaru Forester PZEV Emergency Lane Change Results Initial Speed (km/h) Pylon Hit? (Yes/No) 50 No 55 No 58 No 60 No 60 Yes 60 No 62 No 65 No 68 Yes 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 68 km/h. This result is on par with other vehicles that the eTV program has tested. The maximum lateral acceleration recorded on a successful run was 0.97 G (9.5 m/s2 ).
This, as expected, is higher than the result obtained over the skid pad test. Due to the rapid onset of lateral acceleration in this scenario, the vehicle manages to peak at higher lateral acceleration values before the transition into skidding occurs as traction is lost. 6.4 Noise Emission Tests The Subaru Forester PZEV was tested for noise emissions due to concerns of the additional noise that PZEV technology creates by retarding ignition timing for faster engine warm-up when the vehicle is started. The noise testing performed was in accordance with the CMVSS 1106 Noise Emission 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 8.
25 Figure 8: Noise Emission Test 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;
Before each run, in order to stabilize the transmission and exhaust system temperatures, the vehicle was allowed to idle in neutral for a period of one minute. The test procedure with the vehicle accelerating through the noise measurement zone was as follows:
The vehicle was brought to a speed of 48 km/h ± 1.2 km/h before entering the noise measurement zone;
At the start of the zone (the acceleration point) the throttle was opened wide, accelerating the vehicle;
The vehicle continued to accelerate until it had exited the zone;
The sound meter was set to fast dB(A).
All noise tests on the Subaru PZEV were performed on October 21, 2009. The noise emission tests with the vehicle decelerating followed the same procedure as above, with one modification: at the start of the zone (the deceleration point), the throttle was released, and the vehicle was allowed to decelerate until its speed had dropped to 24 km/h, or it had exited the 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
26 67.9 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 gas-powered lawn mower. The levels measured for the Subaru PZEV are typical for a gasoline powered special purpose 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. Table 12 and Table 13 show the results of the noise emission test. The results satisfy the requirements of the CMVSS 1106 Noise Emission Test.
Table 12: External Noise, Approaching 48 km/h Test Side # Approaching Speed (km/h) Approaching RPM End Speed (km/h) RPM max Noise Level dB (A) Right – 1 48 2700 67 4000 67.4 Right – 2 48 2700 67 4000 68.0 Right – 3 48 2700 67 4000 68.3 Right – 4 48 2700 67 4000 67.8 Average 67 67.9 Left – 1 48 2700 67 4000 67.6 Left – 2 48 2700 67 4000 67.1 Left – 3 48 2700 67 4000 67.3 Left – 4 48 2700 67 4000 66.8 Average 67 67.2 Table 13: External Noise, Approaching 67 km/h Test Side # Approaching Speed (km/h) Approaching RPM End Speed (1) (km/h) RPM max (1) Noise Level dB (A) Right – 1 67 3700 61 3200 65.7 Right – 2 67 3700 61 3200 66.4 Right – 3 67 3700 61 3200 64.9 Right – 4 67 3700 61 3200 65.9 Average 61 65.7 Left – 1 67 3700 61 3200 66.9 Left – 2 67 3700 61 3200 66.1 Left – 3 67 3700 61 3200 67.0 Left – 4 67 3700 61 3200 67.1 Average 61 67.2 Interior noise 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 Subaru PZEV experienced a higher dB within the vehicle than the values recorded externally. The interior noise levels were well below the legal limit, and typical of the special purpose class.
27 Table 14: Interior Noise Test # and Targeted Test Speed Calibration dB (A) Noise Level dB (A) Transmission Selection Idle 93.8 41.5 Neutral Ambient Noise Level 35.4 Engine Off Full Acceleration – 1 93.8 77.7 25 sec. – 135 km/h Full Acceleration – 2 93.8 78.2 25 sec. – 135 km/h Full acceleration – 3 93.8 78.2 25 sec. – 135 km/h Average 78.0 25 sec. – 135 km/h 110 km/h – 1 93.8 73.5 Drive 110 km/h – 2 93.8 72.6 Drive 110 km/h – 3 93.8 72.3 Drive Average 72.8 Drive 100 km/h – 1 93.8 73.0 Drive 100 km/h – 2 93.8 72.8 Drive 100 km/h – 3 93.8 72.9 Drive Average 72.9 Drive 80 km/h – 1 93.8 70.0 Drive 80 km/h – 2 93.8 69.7 Drive 80 km/h – 3 93.8 69.0 Drive Average 69.6 Drive 50 km/h – 1 93.8 65.4 Drive 50 km/h – 2 93.8 64.9 Drive 50 km/h – 3 93.8 66.5 Drive Average 65.6 Drive 6.5 Braking In order to comply with the Canadian Motor Vehicle Safety Standards (CMVSS) and be eligible for the Canadian market, the Subaru Forester (and the PZEV variant) had to pass all required braking tests.
It was therefore decided that testing according to the strict and resource-intensive procedures set out in CMVSS 135 - Light Vehicle Brake Systems was unnecessary. However, a simplified brake testing procedure was performed to determine the stopping distance for abrupt stops from the following speeds:
50 km/h (30 mph) to 0 km/h / (mph) – 6 stops, averaged
80 km/h (50 mph) to 0 km/h / (mph) – 6 stops, averaged
100 km/h (60 mph) to 0 km/h / (mph) – 6 stops, averaged
110 km/h (70 mph) to 0 km/h / (mph) – 6 stops, averaged The vehicle’s total braking distance in metres and time in seconds were recorded.
Since the test vehicle was equipped with ABS brakes, the test driver fully depressed the brake pedal, allowing the computer to modulate the calipers. The braking tests were conducted under the following conditions:
Vehicle loaded with 180 kg
Transmission position: In neutral (N)
Initial brake temperature: ≤ 100°C
Pedal force: as necessary to activate ABS
Wheel lockup: No lockup of any wheel for longer than 0.1 second allowed at speeds greater than 15 km/h
Number of runs: 6
Test surface: Maximum coefficient of friction of 0.9 Figure 9 summarizes the braking results for the Subaru Forester PZEV. The threshold values are the limits that determine failure from given initial speeds. The best stopping distance recorded (out of the six trials) is indicated for each initial speed. Figure 9: Subaru Forester PZEV Braking Performance The Subaru Forester PZEV is fully compliant with all aspects of the CMVSS 135 standard that were tested against.
The braking performance of the Subaru Forester PZEV at all tested speeds is fully satisfactory, as it falls well within the required braking thresholds.
6.6 Summary Remarks Regarding Dynamic Testing All tested aspects of performance, noise emissions, handling and braking were acceptable relative to special purpose AWD vehicles. The vehicle demonstrates, within the parameters of the testing performed, that it is in compliance with CMVSS noise and braking standards. Overall, the dynamic test results show that the Subaru Forester PZEV performs well and does not encompass any observable short-comings relative to comparable on-road vehicles. There is no indication that application of PZEV technology has any noteworthy affect on the performance of a vehicle.
7 PHASE III - ON-ROAD EVALUATIONS The eTV program wanted to evaluate whether PZEV technology affected consumers experience of the vehicle. An effort was coordinated to have individuals test drive the Subaru Forester PZEV and offer feedback on the experience. There have been 15 of these on-road evaluations of the Subaru Forester Partial Zero Emission Vehicle (PZEV). The