A Project Report On Emission Modeling For Two Wheelers

Introduction

Asia has the world’s highest concentration of motorized two- and three-wheeled vehicles. From scooterettes in India to tuk-tuks inThailand to electric bicycles in China, these vehicles dominate the Asian urban landscape. Ownership and use are also increasing inrural areas where distances traveled are greater and fuel quality may be less reliable. These trends are serving to worsen energy the environment impacts worldwide. And while motorcycles are currently among the most fuel efficient motorized modes of personal transportation, rapid growth in population coupled with the increasingpopularity of larger and less efficient models are eroding this sector’s energy and emission performance. If Asian cities are to achieve healthy air, provide sustainable energy systems, maintain road safety, and reduce greenhouse gas, they must deal with two- and three-wheeled motor vehicles. This requires a comprehensive strategy, one that can be adapted and used throughout the world. The purpose of this report is to identify opportunities to better manage emissions and fuel use from two- and three-wheelers.

The focus is Asia. Today, China and India produce the majority of the two- and three wheelers sold. Although the largest share of these motorcycles is destined to local markets, exports to neighboring countries and beyond are growing rapidly. Indeed motorcycle sales are soaring in many Asian countries and motorcycles are increasingly popular in Latin America, Africa, and elsewhere. Moreover, the ability to better manage motorcycles extends beyond Asia and the developing world. European nations, including Italy, Spain, Greece, and others, will all benefit from cleaner motorcycles. And while they are not the focus of this report, noise and safety concerns raised by motorcycles also merit attention as part of a comprehensive motorcycle strategy. The policies discussed in this report are based on the experience of regulators in major motorcycle countries and regions, such as China, India, Thailand, and the European Union, as well as the recommendations of other experts in the field. This report reviews current trends in motorcycle emissions and fuel efficiency technology and performance, summarizes policy approaches to improve motorcycle emission and energy performance, and discusses what is required to implement these policies. The choices China, India, and others make to control motorcycle emissions and fuel use will have a significant impact within their borders and throughout the world. China, for example, has adopted its first set of fuel economy standards in 2009 while simultaneously implementing an enhanced version of Euro 3, the latest Europeanemission standards.

The Euro program is emerging as the global norm with countries such as Thailand and Vietnam adoption standards based on the European program. India has maintained its unique program with standards based on the Indian Driving Cycle. Current motorcycle emission standards in China, India, the EU and elsewhere are not directly comparable in terms of their relative stringency. On the fuel consumption front, both China and India are breaking new ground. China has adopted standards that are just coming into force in 2009. India is currently developing a labeling program that may lead to standards in the near future. Most of the research done in this report was conducted in 2007 and 2008. All other data cited from sources prior to these years are specified accordingly.

Types Of Motorcycles

Visit any country in Asia, and elsewhere around the globe, and you will see a colorful assortment of motorized vehicles in many different varieties. Two- wheelers are as shown in photo. These vehicles typically carry up to two adult passengers for their own personal mobility. But they can also be used to carry small freight or to conveyPassengers for commercial purposes. Two-wheelers are mainly used as personal vehicles for urban mobility. In most of city it is used personal mobility, they are also usedfor commercial passenger transportation. Three-wheelers have wider applications. In Asian and other cities, these vehicles arecommonly used for commercial passenger, family, and goods transport.

Motorcycles And Air Pollution

Motorcycles, as with all other internal combustion engine-powered vehicles, emit the products of full and partial fuel combustion. Several of these emitted products have been identified as direct orindirect causes of air pollution. These include particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons(HC), sulfur oxides (SOx), which varies with the fuel’s sulfur content, and lead compounds if the fuel used is leaded. Exposure to these pollutants is associated with a host of serious health effects including premature death, aggravated respiratory and heart disease, and neurological damage. The US Environmental Protection Agency and World Health Organization have additional information on the societal impacts of air pollution. In addition to conventional air pollutants, motorcycles and other motor vehicles emit toxic compounds that are also of public health concern. Exposure to benzene, formaldehyde, acetaldehyde, acrolein, 1,3- butadiene, and polycyclic aromatic hydrocarbons (PAH) present in motorcycle emissions has been associated over the long term with increased cancer risk, while short term exposure is associated with respiratory and neurological effects.

Emission Testing In Delhi From Two Wheelers

A study in Delhi, India found the highest levels of fine particulate exposure (referred to in the study as respirable suspended particles or RSP) and CO occurred during commute activities on two- and three-wheelers (Saksena et al. 2007). Mean exposures to RSP and CO were among the highest of all indoor and outdoor microenvironments and activities. The integrated daily average exposure across all subjects was found to be several times the Indian residential standard. The integrated CO 8-hour exposure was just under the standard, however the authors found that some subsets of the population were exposed to levels up to 40 percent higher than the Standard.

Motorcycle Emission Standards

This section covers the regulatory practices that lead to the adoption of best available emission control technologies in new motorcycles. The discussion focuses on existing regulatory programs, in particularthe programs developed in nations and regions where motorcycles significantly contribute to air pollution. Taiwan, India,Thailand, and China have been leaders in elements of a comprehensive strategy to control emissions from motorcycles, including the adoption ofstringent emission standards. It is important to review the air quality management framework in these policies fit. Regulations and fiscal policies aimed at reducing emissions can improve vehicle performance or change usage patterns. Both of these outcomes can reduce pollution exposure and associated health impacts. Considerations such as cost and costeffectiveness (cost per amount of emission reduced) are often used to prioritize among various control measures. Fuel use policiesfit in similar energy conservation and greenhouse gas management frameworks. A new motorcycle emission control program includes standards and a compliance process to ensure that manufacturers comply with adopted standards. Emission standards are typically expressed as the mass of a specific pollutant to be emitted over a distance traveled by the vehicle (i. e. , grams/ kilometer). During the type-approval process, manufacturers must demonstrate that their pre-production models meet the emission standards over their useful lifetime, represented by an accumulated distanced traveled (or durability distance).

Motorcycle Emissions In-use Requirements

Motorcycle inspection and maintenance (I&M) are an important part of the framework to check that control systems are in working order. I&M is typically part of a larger emissions testing program covering cars and light trucks. Under inspection and maintenance programs, vehicles’ emissions (and safety) are required to be inspected and tested at regular intervals, usually annually or bi-annually. The vehicles that fail to meet in use standards must be repaired and retested. I&M programs thus create an incentive for vehicle owners to perform preventative maintenance to ensure their vehicles will passinspection. This discussion focuses solely on the motorcycle components of I&M programs. I&M programs can be centralized or decentralized. In a centralized system, only a few large facilities provide testing. Centralized stations are typically test-only stations that are operated by the government. In a decentralized system there are many smaller, often private facilities that provide both testing and repair services. Each structure has its advantages and disadvantages. Vehicle emission testing facilities can be public, private, or a hybrid arrangement. Hybrid testing can entail a mix of public and licensed private facilities in a decentralized structure or a private company contracted to operate test-only facilities in a centralized structure. If testing is provided by the private sector, it is important that contractorselection and facility licensing follow a rigorous and transparent process (Walsh 2005). Outsourcing of the testing or even the management of an I&M program requires continued government oversight to ensure the quality of the work performed. Transparency is key to public acceptance of I&M programs.

Two-wheeler Use Restrictions

Motorcycle usage restrictions prohibit all, or some types of, motorcycles (e. g. two-stroke motorcycles, motorcycles older than 10years) from operating on certain roads or within certain parts of a city. Use restrictions are most common in the congested city center. Decisions on road usage and restrictions are usually under the preview of city regulators. Use restrictions are intended not only to reduce emissions in densely populated areas, but also to reduce traffic congestion, accidents, noise, and other societal problems. In Guangzhou, China, motorcycle gangs created public safety problems leading to a ban on all motorcycles from the city center (Yardley 2007). Several large cities,including Jakarta and Lahore, have issued similar bans on motorcycle operation in the central business district, limiting motorcycle use to suburbs and rural areas (Roychowdhury et al. 2006). Chinese cities’motorcycle bans came on the heels of limiting new motorcycle registrations in the late 1990s. By 2000, 37 cities were no longerissuing new registrations and 21 additional cities had limited the number of new registrations allowed (Roychowdhury et al. 2006). Lahore in Pakistan is implementing a ban on two-stroke three-wheelers in the city’s major arteries. Table 6-8 provides additional details on several current and proposed motorcycle bans throughout Asia. A number of usage restrictions have focused on commercial three wheelers powered with two-stroke engines. Usage restriction proposals are often met with significant opposition from owners and operators. Equity concerns often arise when such programs are announced, as most commercial motorcycle operators’ limited incomes depend heavily on operating in city centers. In Dhaka, for example, workshops were held with affected stakeholders, including drivers, owners, and service providers to develop rehabilitation plans.

Emission Test Procedures

The vehicle emission limits are specified based on a standard test procedure, which includes; A specified vehicle driving or engine operation schedule of varying speeds and loads which represents real life driving/usage pattern of the vehicles and engines. The test schedule of vehicle or engine operation is known as ‘driving cycle’. Use of emission sampling systems and analyzers that operate on the working principles specified in the emission regulations. The new production vehicles and engines are tested for compliance with the emission standards in a government approved laboratory. The USA and particularly the state of California have led the world in developing vehicle emission test methods and in setting the vehicle emission limits. The test cycles used in the USA, Europe and Japan for emission measurement and certification of vehicles/engines for compliance with the standards differ and so also the numerical values of the emission limits. Therefore, direct comparison between standards in different countries is generally not possible.

Units Of Emission Limits

Two types of emission limits are specified in the standards For the light and medium duty vehicles, passenger cars and, two and three wheelers are in terms of mass of pollutant emitted per unit distance travelled i. e. , g/km ( g/mile in the USA, 1 g/km =1. 61 g/mile). For heavy duty vehicles and engines test is carried on the engine itself and the limits are specified in terms of mass of pollutant per unit of work done, i. e. , g/kW-h or g/bhp-h (1 g/kW-h = 1. 34 g/bhp-h). The test cycle and measurement procedures have been accordingly developed whether test is to be done on a vehicle or on the engine.

Emission Test Cycles

The US and European driving cycles used for emission measurement are presented below. Most of the other countries follow either the European or the US test methods except Japan which has its owndriving cycles. In India European test methods are used except for the motorcycles and three wheelers. Driving Cycles for Light Duty VehiclesThe emission test driving cycles are composed of a cold start period, idling, moderate acceleration and deceleration, and cruise modes. The test cycle is given in terms of vehicle speed versus time. The lightand medium duty vehicles are driven through the prescribed driving cycle on a chassis roller dynamometer. During operation the engine is required to develop road horse power that depends onthe vehicle speed for a given vehicle. The road horsepower requirement versus speed data as provided by the vehicle manufacturer or determined by vehicle coast down test is stored into chassis dynamometer controller to simulate the real life road operation of the vehicle. The vehicle weight i. e. inertia needed during transient modes of the driving cycle is simulated by mechanically changing the rotating masses or electronically changing the inertia on the roller dynamometer. A typical emission test facility with a vehicle operating on chassis dynamometer is shown in Fig 1 [image: ] Figure 1 View of a vehicle emission test and chassis dynamometerFacilityEuropean Test Driving CycleThe driving cycles followed in Europe for light and medium duty vehicles is shown in Fig. 2. The European test cycle is composed of steady operation modes derived from the actual vehicle operationdata on road. Although it consists of acceleration and deceleration modes but as all the modes represent averaged operating conditions, the cycle is often referred to as steady mode cycle.

The European test cycle as given in Fig. 2 was implemented from Euro 1 emission standards in 1992. It has two parts;(i) an urban driving cycle (ECE 15) and (ii) an extra-urban driving cycle (EUDC)The break-up of different operating modes in the two parts of the cycle is also given in Figure 2. ECE-15 cycles EUDC cycle Distance,km 4. 052 6. 955 Time, s 780 400 Averge speed,km/h 19 62. 5 Maximum speed,km/h 50 120 Acceleration,%time 21016 - Maximum acceleration,m/s^2 - 0. 833 Deceleration,%time 1308 - Maximum Deceleration, m/s^2 - -1. 38 Idle,%time 35. 4 - Steady speed,%time 29. 3 -Figure 2 European driving cycle for light and medium duty vehicles: ECE 15 cycle followed by extra urban driving cycle (EUDC). Prior to Euro 1 regulations, only the ECE 15 cycle was used. The low speed urban test cycle consists of repetition of 15 mode cycle four times without interruption for a total duration of 780 seconds. The totalDistance covered is 4. 052 km at an average speed of 19 km/h. The high-speed test cycle called as Extra Urban Driving Cycle (EUDC) is carried out after the ECE-15 cycle. This high-speed cycle has maximum speed of 120 km/h. The EUDC part gives a higher contribution to NOx while the ECE-15 cycle has more contribution to CO and HC emissions. Emission measurement commences with the engine cold start at the beginning of the first ECE-15 mode cycle itself. The emissions are measured using CVS technique as explained later.

The first European test procedure for heavy duty vehicles, R-49 used 13-mode test having five different load points each at the rated and peak torque speeds and three idling speed points one in thebeginning one in the middle and the third at the end. Each mode had a different weighing factor. A new test procedure has been adopted from the year 2000 along with implementation of Euro 3 standards. It consists of two separate tests each of about 30 minutes duration as below;(i) 13-mode steady state cycle (ESC) with a dynamic load response (ELR) smoke test(ii) A transient test cycle (ETC)The steady state cycle (ESC) is used to prevent abnormally high emissions if an engine is made to operate at extreme conditions where emission controls may not be very effective.

On the other hand, the transient cycle (ETC) represents the actual operating conditions and is better suited for the engines operating on alternative fuels or employing after treatment devices. For certification to Euro 3 standards, the conventional diesel engines are tested by the ESC only. However, the diesel engines with advanced emission control systems such as after-treatment devices and the SI engines such as natural gasengines are tested by both the procedures. From the Euro 4 standards implemented in year 2005, all heavy-duty engines are tested by both the ESC and ETC test procedures. ESC and ELR TestsThe ESC and ELR test procedures are shown in Fig. Weighting factors for the ESC test for each mode are also shown on Fig. The test is carried out at three engine speeds and idle. The test speeds are determined as shown on Fig. At each of the three speeds, emissions are measured at 25%, 50%, 75% and 100 % loads. To ensure that there are no abnormal operating conditions which could result in abnormally high emissions, testing agency is authorized to select three more modes as indicated. The dynamic load response (ELR) test is carried out for smoke emissions. The engine is accelerated from 10% load to full load at maximum possible acceleration.

In this way engine runs through the entire fuel/air ratios defined by the engine fuel management system. Thus, smoke emission from the diesel engines is measured for the entire range of fuel delivery i. e. fuel-air ratios. Peak smokes emissions are compared with the Permissible limits as specified in the standards. The vehicle speed –time and normalized torque -time curves for the ETC are shown in Fig. The cycle was derived from the data collected on different road types i. e. , highway, urban and rural roads, under varying traffic density, road gradients and distance between stopping points. The data were collected for different types of vehicles such as trucks, buses and city buses. The normalized figures are integrated in three sub-cycles of 10 minutes each.

For establishing limits, emissions from the three sub- parts of the cycle may be measured separately and later combined using weighting factors. In the USA until 1984, a steady state test cycle consisting of 13 different engine speed and load combinations was used for measurement of gaseous exhaust emissions from the heavy-duty vehicle engines. Emissions were measured under engine idling, and at rated and maximum torque engine speeds as in European R-49 cycle but at different engine loads and the engine operating modes had different weighting factors than the European test procedure. From 1985, a transient mode test replaced the 13-mode test. This test cycle was developed from the driving pattern data measured in New York and Los Angeles. The cycle represents driving pattern only for the city operation. It contains the traffic characteristics of congested urban, uncongested urban and city expressway driving. The US transientcycle test is run over a full range of load and speed conditions with equal weighing factor to each operation point of the cycle. The total test consists of three phases, cold start cycle, hot soak and hot start cycle; each phase of 20 minutes duration. Data on engine speed, load and gaseous emissions are monitored once per second. Computer controlled engine test bed and data acquisition are used. The emission results are integrated over the test cycle. The weighting factors for the cold start and hot start cycles are 1/7 and 6/7, respectively.

Recommendations

In countries where motorcycles are a major contributor to air pollution problems, a comprehensive plan is needed to effectively and efficiently control these vehicles. This plan should include:

1. A platform for world harmonization of motorcycle emission standards that accelerates the use of proven, cost-effective, advanced technologies
2. A parallel policy effort, with coordinated strategies, to reduce motorcycle fuel use and carbon emissions.
3. Emission standards for new motorcycles with durability requirements that reflect real world useful life, cold start testing, andlimits on evaporative emissions.
4. A thorough compliance program to enforce adopted emission standards.
5. Routine enforcement activities, such as vehicle recall systems thatminimize the risk of fraud and ensure that manufacturers are building motorcycles to required specification is important, especially during the production of first generation of models subject to revised emissions standards.
6. Emissions standards coupled with fuel quality standards to fully enable cleaner vehicle technologies.
7. Standards for lubricating oil quality for two-stroke motorcycles andpremix dispensing facilities to prevent inappropriate dosage.
8. Strategies to address in-use motorcycle emissions, including in useemission standards, retrofit and vehicle programs, usage restrictions,and inspection and maintenance programs.
9. Analysis that takes local factors into account and directs appropriate strategies to promote the use of alternative fuels.