VM 4: TECHNOLOGY

4.2.17 What vehicles are covered in the proposed standards? (p.100)

The majority of these vehicles carry payloads of goods or equipment, in addition to passengers

4.1.2 What are Hybrid-Electric vehicles? (p.88)

Vehicles that use both an internal combustion engine and electric power

4.2.9 What are the three main regulatory categories of the HD National Program proposed by the EPA and the NHTSA? (p.98)

(1) combination tractors; 5 (2) heavy-duty pickup trucks and vans; and (3) vocational vehicles.

4.1.8 In what conditions does a Series Hybrid perform optimally? (p.90)

stop-and-go driving, series hybrids perform at their best in such conditions.

4.2.13 What are the proposed standards for N2O and CH4 emissions? (p.99)

. EPA's proposed standards would act to cap emissions to ensure that manufacturers do not allow the N2O and CH4 emissions of their future engines to increase significantly above the currently controlled low levels.

4.2.18 What two metrics are proposed in the standard? (p.100)

. payload-dependent gram per mile (and gallon per 100-mile) standards for pickups and vans; and gram per ton-mile (and gallon per 1,000 ton-mile) standards proposed for vocational vehicles and combination tractors.

4.3.4 What is a Partial Zero Emission Vehicle? (p. 105)

A partial zero emissions vehicle is a vehicle that has zero evaporative emissions from its fuel system, has a 15-year (or at least 150,000-mile) warranty on its emission-control components, and meets SULEV (Super Ultra Low Emission Vehicle) tailpipe-emission standard.

4.3.2 What is Active Fuel Management? (p. 103)

Active Fuel Management (formerly known as displacement on demand (DoD)) is a trademarked name for the automobile variable displacement technology from General Motors. It allows a V6 or V8 engine to "turn off" half of the cylinders under light-load conditions to improve fuel economy.

4.7.3 What is an Auxiliary Power Unit? (p.116)

Auxiliary power units (APUs) are portable, vehicle-mounted systems that provide power for climate control and electrical devices in trucks, locomotives, and marine vehicles without idling. These systems are generally composed of a small internal combustion engine (usually diesel) equipped with a generator to provide electricity and heat.

4.7.14 What technologies might be replaced by TES systems? (p.119)

Battery-electric air conditioners (storage cooling) derive energy to recharge the storage device from the truck's engine during operation or from plugging in to external power sources at truck stops. The engine uses a small quantity of extra diesel for recharging the air conditioner. The emissions from burning this fuel (which are controlled by the engine's emissions control system) occur on the highway rather than at the truck stop or depot

4.7.5 What is a coolant heater? (p.116)

Coolant heaters use the truck's regular heat-transfer system. The heater is mounted in the engine compartment, draws gasoline or diesel from the fuel tank to heat the vehicle's coolant, and pumps the heated coolant through the engine, radiator, and heater box. Coolant heaters keep the engine warm, reducing the impact of cold starts

4.4.7 What is Selective Catalytic Reduction (SCR)? (p.109)

DEF-Selective Catalytic Reduction is an advanced active emissions control technology system that injects a liquid-reductant agent through a special catalyst into the exhaust stream of a diesel engine. The reductant source is usually automotive-grade urea, otherwise known as Diesel Exhaust Fluid (DEF).

4.5.2 What is the difference between a Dedicated Natural Gas Vehicle and a Bi-Fuel Natural Gas Vehicle? (p.113)

Dedicated natural gas vehicles are designed to run on natural gas only, while dual-fuel or bi-fuel vehicles can also run on gasoline or diesel.

4.7.17 What is a Dual-System Electrification? (p.120)

Dual-system electrification, also known as "shorepower," requires both onboard and off-board equipment so trucks can plug into electrical outlets at the truck stop. To use dual-system electrification, trucks must be equipped with AC equipment or an inverter to convert 120-volt power, electrical equipment, and hardware to plug into the electrical outlet. Necessary electrical equipment might include an electrical HVAC system

4.2.20 How are the proposed corporate average standards for Heavy-Duty pickup trucks and vans determined? (p.101-102)

EPA is proposing to establish standards for this segment in the form of a set of target standard curves, based on a "work factor" that combines a vehicle's payload, towing capabilities, and whether it has4-wheel drive. The standards would phase in with increasing stringency in each model year from 2014 to 2018.

4.4.1 What are the differences between direct and indirect injection? (p.107)

Earlier electronic diesel fuel systems, relying on simpler injectors, often injected into a sub-chamber shaped to swirl the compressed air and improve combustion; this was known as indirect injection. However, this was less efficient than the now common direct injection in which initiation of combustion takes place in a depression (often toroidal) in the crown of the piston. All diesel engines use some type of fuel injection by design (Figure 4.13).

4.7.6 How can an energy recovery system help heat a transport cab? (p.117)

Energy recovery systems use the vehicle's heat-transfer system, much like a coolant heater, but without a separate piece of equipment. A very small electric pump is connected to the water line, which keeps the truck's cooling system and heater operating after the engine is turned off, using engine heat that would otherwise dissipate. Energy recovery systems typically do not provide enough warmth to be a sole source of overnight heat.

4.2.2 How much might these standards reduce greenhouse gas emissions (GHG)? (P.96)

Estimates state the combined standards have the potential to reduce GHG emissions by nearly 250 million metric tons and save approximately 500 million barrels of oil over the life of vehicles sold during 2014 to 2018

4.1.20 What are some of the drawbacks of using Ethanol as a fuel? (p.95)

Ethanol is caustic and can slowly decompose certain rubber compounds such as are found in the fuel lines and seals in vehicles produced before the mid-1980s. Because gasoline is more volatile than Ethanol, it can be harder to start some engines using higher ethanol percentages than they were designed to use. Ethanol is also electrically conductive, unlike gasoline which is an effective insulator, and can cause problems with some early electric fuel pump designs and fuel tank sensors. Corrosion of magnesium and aluminum parts is also a concern at higher ethanol percentages. Ethanol has less energy per volume than gasoline, so miles-per-gallon ratings with ethanol mixtures are significantly worse than with pure gasoline.

4.1.19 How is Ethanol used as a fuel for vehicles? (p.95)

Ethanol is obtained from sugar or starch in crops and other agricultural produce such as grain, sugarcane or even lactose. E85 ethanol is an alternative fuel to gasoline. It is a high octane, cleaner burning fuel that is a blend of 85 percent ethanol and 15 percent gasoline.

4.3.7 How can Exhaust Systems help reduce emissions? (p. 106)

Exhaust emissions are cleaner because the more precise and accurate fuel metering reduces the concentration of toxic combustion byproducts leaving the engine.

4.2.10 What types of vehicles are included in the proposal? (p.98)

For purposes of this proposal, the heavy-duty fleet incorporates all on-road vehicles rated at a gross vehicle weight at or above 8,500 pounds, and the engines that power them, except those covered by the current GHG emissions and Corporate Average Fuel Economy standards for model years 2012-2016.

4.4.3 What is the history of vehicles that have used EGR? (p.108)

From 1972/73 to the late 1980s EGR was commonly used for NOx control in gasoline fueled passenger car and light-duty truck engines in North America. After the early 1990s, EGR was also introduced to diesel passenger cars and light-duty trucks and then heavy-duty diesel engines. While there were applications to heavy-duty diesel dating back to the 1970s, it was not until the early 2000s that cooled EGR became very common in heavy-duty diesel engines in North America [Hawley 1999]. After 2010, the application of EGR into light-duty gasoline engines was expanded—not for NOx control but for fuel economy purposes.

4.3.6 How can Electronic Fuel Injection help improve fuel efficiency? (p. 106)

Fuel injection generally increases engine fuel efficiency. With the improved cylinder-to-cylinder fuel distribution of multi-point fuel injection, less fuel is needed for the same power output

4.1.6 What is a Full Hybrid? (p.89)

Full hybrids can use the electric motor as the sole source of propulsion for low-speed, low-acceleration driving, such as in stop-and go traffic or for backing up. This electric-only driving mode can further increase fuel efficiency under some driving conditions. In a full hybrid the electric motor and IC engine turn wheels alone or together depending on demand and battery charge.

4.4.4 How can EGR be used in conjunction with other technologies to reduce GHG's? (p.108)

However, to meet more stringent NOx emission limits, it may be necessary to use EGR in combination with NOx reduction catalysts (Figure 4.14).

4.4.2 What is Exhaust Gas Recirculation? (p.107)

I EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders.

4.1.14 What types of fuel reductions were seen in the Hybrid International Truck and Engine utility vehicles that were tested as part of the HTUF pilot program? (p.93-94)

I40% to 60% decrease in the amount of fuel used, as well as emissions-reduction benefits, significantly exceeding expectations.

4.4.11 What system is being used by NVFEL in order to analyze different engine and transmission combinations in order to predict their emissions? (p.111)

In 2012, NVFEL's National Center for Advanced Technology (NCAT) developed a special laboratory test program to assess the effectiveness of a broad range of key light-duty vehicle technologies to better understand their potential for enabling manufacturers to meet EPA's 2017-2025 light-duty vehicle Greenhouse Gas standards.

4.1.7 What is a Series Hybrid vehicle? (p.89)

In a series hybrid, the electric motor is the only means of providing power to get your wheels turning. The motor receives electric power from either the battery pack or from a generator run by a gasoline engine. While the engine in a conventional vehicle operates inefficiently in order to satisfy varying power demands of stop-and-go driving, series hybrids perform at their best in such conditions. This is because the gasoline engine in a series hybrid is not coupled to the wheels. This means the engine is no longer subject to the widely varying power demands experienced in stop-and-go driving and can instead operate in a narrow power range at near optimum efficiency. h (Figure 4.2). Series type hybrids are appropriate for large vehicles allowing internal combustion engines to generate the electricity to power powerful electric motors. "Diesel" locomotives are the epitome of this technology

4.1.12 What is a two mode Hybrid system? (p.93)

In the first mode, at low speed and light loads, the vehicle can operate in three ways: electric power only, engine power only or in any combination of engine and electric power. The second mode is used primarily at highway speeds. In addition to electric assist, the second mode provides full engine power when conditions demand it, such as when passing, pulling a trailer or climbing a steep grade. Two-mode hybrids hold promise for improving fuel efficiency at highway speeds and for use in pickups, vans and SUVs which are so popular in the US.

4.1.16 How can natural gas be used by fleet managers as a fuel? (p.94-95)

Natural gas, a fossil fuel comprised mostly of methane is one of the cleanest burning alternative fuels. It can be used in the form of compressed natural gas (CNG) or liquefied natural gas (LNG) to fuel cars and trucks Dedicated natural gas vehicles are designed to run on natural gas only, while dual-fuel or bi-fuel vehicles can also run on gasoline or diesel.

4.5.1 What is Natural Gas? What two forms are used as fuel for vehicles? (p.113)

Natural gas, a fossil fuel comprised mostly of methane, It can be used in the form of compressed natural gas (CNG) or liquefied natural gas (LNG)

4.6.2 What is the power of a Propane powered vehicle in comparison to a Gasoline powered vehicle? (p.114)

Propane vehicle power, acceleration, and cruising speed are similar to those of gasoline-powered vehicles.

4.6.5 How can Propane powered vehicles be acquired? (p.114-115)

Propane vehicles can either be from an original equipment manufacturer (OEM) or conversions. Certified installers can economically and reliably retrofit many light-duty vehicles for propane operation

4.6.4 How do Propane powered vehicles work? (p. 114)

Propane vehicles work much like gasoline-powered vehicles with spark-ignited engines. Propane is stored as a liquid in a relatively low-pressure tank (about 300 pounds per square inch). Liquid propane travels along a fuel line into the engine compartment. The supply of propane to the engine is controlled by a regulator or vaporizer, which converts the liquid propane to a vapor. The vapor is fed to a mixer located near the intake manifold, where it is metered and mixed with filtered air before being drawn into the combustion chamber where it is burned to produce power, just like gasoline.

4.4.8 How can SCR reduce emissions? (p.109-110)

SCR technology is one of the most cost-effective and fuel-efficient technologies available to help reduce diesel engine emissions. All heavy-duty diesel truck engines produced after January 1, 2010 must meet the latest EPA emissions standards, among the most stringent in the world, reducing particulate matter (PM) and nitrogen oxides (NOx) to near zero levels. SCR can reduce NOx emissions up to 90 percent while simultaneously reducing HC and CO emissions by 50-90 percent, and PM emissions by 30-50 percent. SCR systems can also be combined with a diesel particulate filter to achieve even greater emission reductions for PM.

4.2.5 How can the government help to reduce our dependence on foreign oil? (p.97)

Setting fuel consumption standards for the heavy-duty sector will improve our energy security by reducing our dependence on foreign oil, which has been a national objective since the first oil price shocks in the 1970s.

4.1.13 How can Hybrid technologies help to operate a power take off shaft without the use of an internal combustion engine? (p.93)

Some hybrid designs use electric motors supplied by batteries to perform this work instead, thereby saving significant fuel, pollution and internal combustion engine wear.

4.1.10 How can a Parallel Hybrid system serve as an AWD system? (p.91)

Some up-and-coming hybrid models use a second electric motor to drive the rear wheels, providing electronic all-wheel drive that can improve handling and driving in bad weather conditions. Parallel hybrids run the full gambit in production sizes including sedans, medium-duty trucks and buses.

4.3.3 What is the Atkinson Cycle engine and how might its implementation help improve fuel economy? (p. 104)

The Atkinson-cycle engine is a type of internal combustion engine invented by James Atkinson in 1882. Potential Fuel Economy Improvements from the Implementation of cooled exhaust gas recirculation (cEGR) and cylinder deactivation (CDA) on an Atkinson Cycle Engine is as follows:

4.4.10 What sort of Certification and Compliance testing does the NVFEL perform on Light - Medium Duty Engines? (p.110-111)

The National Vehicle and Fuel Emissions Laboratory (NVFEL) tests a portion of all heavy-duty diesel and small gasoline engines intended for sale in the United States to confirm compliance with EPA's exhaust emissions standards. This includes on road and off-road diesel engines 200 horse power (HP) and larger, and non-road gasoline engines 30HP and smaller.

4.5.3 What are the advantages of Natural Gas-Powered Vehicle's? (p.113)

The advantages of natural gas include the fact that nearly 87 percent of U.S. natural gas used is domestically produced, it produces 60-90 percent less smog-producing pollutants and 30-40 percent less greenhouse gas emissions, and it is less expensive than gasoline

4.1.17 What are the advantages of using Natural Gas as a fuel? (p.95)

The advantages of natural gas include the fact that nearly 87 percent of U.S. natural gas used is domestically produced, it produces 60-90 percent less smog-producing pollutants and 30-40 percent less greenhouse gas emissions, and it is less expensive than gasoline.

4.2.12 How are the EPA and NHTSA collaborating in order to reduce greenhouse gas emissions? (p.98)

The agencies are developing these rules collaboratively under their respective authorities: the EPA is proposing GHG emissions standards under the Clean Air Act, and NHTSA is proposing fuel efficiency standards under EISA. The goal of the joint rulemakings is to produce coordinated federal standards that help manufacturers to build a single fleet of vehicles and engines that can comply with both.

4.2.22 How will the proposed standards regulate them? (p.102)

The agencies are proposing to divide this segment into three regulatory subcategories which is consistent with the engine classification. • Light Heavy (Class 2b through 5) • Medium Heavy (Class 6 and 7) • Heavy (Class 8)

4.1.15 What is the difference between an Electric Vehicle and a Hybrid Vehicle? (p.94)

The difference between an electric vehicle and a hybrid vehicle is that in a true electric vehicle only the all-electric motor supplies power to the wheels of the car at all times. The electric motor gets its energy from a very powerful high voltage battery pack that can store enough energy to drive the car a limited number of miles.

4.1.5 How do hybrid electric drive systems function? (p.89)

The engine provides most of the vehicle's power, and the electric motor provides additional power when needed, such as for accelerating and passing. This allows a smaller, more efficient engine to be used. Hybrid electric motors supplement internal combustion (IC) engine by turning wheels

4.2.16 What additional credit opportunities are available in the proposed HD National Program? (p.100)

The first is an early credit option intended for manufacturers who demonstrate improvements in excess of a proposed standard prior to the model year that it becomes effective. The second is a credit program intended to promote implementation of advanced technologies, such as hybrid powertrains, Rankine cycle engines, and electric or fuel cell vehicles. The last is a credit intended to apply to new and innovative technologies that reduce vehicle CO2 emissions and fuel consumption,

4.5.4 How available is the technology today? (p.113)

The major disadvantages are limited vehicle availability, it is less readily available than gasoline and diesel, and you get fewer miles on a tank of fuel.

4.7.7 How do Thermal Energy Storage Systems Function (TES)? (p.117)

Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used at a later time for heating and cooling applications and power generation. TES

4.7.9 What is the difference between a centralized and distributed systems? (p.118)

Thermal energy storage systems can be either centralized or distributed systems. Centralized applications can be used in district heating or cooling systems, large industrial plants, combined heat and power plants, or in renewable power plants (e.g. CSP plants). Distributed systems are mostly applied in domestic or commercial buildings to capture solar energy for water and space heating or cooling. In both cases, TES systems may reduce energy demand at peak times.

4.7.4 How can a Cab Heating system reduce fuel consumption? (p.116)

These diesel-fired heaters supply warm air to the cab or bunk. An engine block heater can also be included. Diesel heaters use only small amounts of fuel and have very low emissions because they supply heat directly from a small combustion flame to a heat exchanger. Standard diesel fuel is used. Cab or bunk heaters can be coupled with air conditioners if the trucker's service area includes both cold winters and hot summers

4.1.11 What is a Series/Parallel Hybrid system? (p.91)

This drivetrain merges the advantages and complications of the parallel and series drivetrains. By combining the two designs, the engine can both drive the wheels directly (as in the parallel drivetrain) and be effectively disconnected from the wheels so that only the electric motor powers the wheels (as in the series drivetrain). The Toyota Prius has made this concept popular, and a similar technology is also in the new Ford Escape Hybrid. As a result of this dual drivetrain, the engine operates at near optimum efficiency more often.

4.2.11 Are trailers with engines covered by the proposal? (p.98)

Trailers with engines are not covered under this proposal,

4.2.6 How does the transportation industry contribute to greenhouse gas emissions?(p.97)

Transportation sources emitted 29 percent of all U.S. GHG emissions in 2007 and have been the fastest-growing source of U.S. GHG emissions since 1990. Within the transportation sector, heavy-duty vehicles are the fastest-growing contributor to GHG emissions.

4.3.1 What is Variable Valve Timing? (p.103)

Variable valve operating methods can be traced as far back as the steam age. In internal combustion engines, variable valve timing (VVT) is the process of altering the timing of a valve lift event, and is often used to improve performance, fuel economy or emissions.

4.2.21 What are Vocational Vehicles? (p.102)

Vocational vehicles consist of a very wide variety of truck and bus types including delivery, refuse, utility, dump, cement, transit bus, shuttle bus, school bus, emergency vehicles, motor homes, tow trucks, and many more.

4.2.8 What are the costs of the proposed HD National Program? (p.97)

approximately $7.7 billion, and generate total societal benefits of $49 billion, providing $41 billion in net benefits as a result of the standards over the lifetimes of model year 2014¬ 2018 vehicles, discounted at three percent. Using technologies commercially available today, the majority of vehicles would see a payback period of one to two years, while others, especially those with lower annual miles, would experience payback periods of four to five years.

4.4.6 How effective can DPF's be at reducing emissions? (p.109)

by 85 to 90 percent or more. EPA's Verified Technology List also shows that certain DPFs reduce emissions of hydrocarbons and CO by 70 to 90 percent.

4.2.1 What program was enacted by the EPA and Department of transportation's National Traffic Safety Administration in 2016 to reduce greenhouse gasses? (p.96)

enacted a first-ever program to reduce greenhouse gas (GHG) emissions and improve fuel efficiency of medium- and heavy-duty vehicles, such as the largest pickup trucks and vans, semi-trucks, and all types and sizes of work trucks and buses in between.

4.1.9 What is a Parallel Hybrid vehicle? (p.90)

engine and electric motor run at same time. not as efficient in city driving. With a parallel hybrid electric vehicle, both the engine and the electric motor generate the power that drives the wheels. The addition of computer controls and a transmission allow these components to work together. This is the technology in the Insight, Civic, and Accord hybrids from Honda. Honda calls it their Integrated Motor Assist (IMA) technology.

4.2.7 What are the benefits of the proposed HD National Program? (p.97-98)

reduce GHG emissions by nearly 250 million metric tons and save approximately 500 million barrels of oil over the life of vehicles sold during 2014 to 2018.

4.2.14 How do air conditioning systems contribute to GHG emissions? (p.99)

refrigerant leakage and indirect emissions due to the extra load on the vehicle's engine to provide power to the air conditioning system.

4.2.19 How did the SmartWay Transportation Partnership contribute to the HD National Program? (p.100)

the agencies have drawn from the SmartWay Transport Partnership Program experience to identify technologies as well as operational approaches that fleet owners, drivers, and freight customers can incorporate. NHTSA and EPA believe that operational measures promoted by SmartWay can complement the proposed standards and provide benefits for the existing heavy-duty fleet.

4.4.12 What tests does the NVFEL perform on Heavy Duty Engines? (p.112)

the engine testing center has been mapping out the fuel consumption of heavy-duty engines at various operating conditions and using the results to validate Office of Transportation and Air Quality's (OTAQ) heavy-duty Greenhouse Gas Emissions Model (GEM).

4.2.4 What are two intertwined and critically important needs of the US? (p.97)

to reduce oil consumption and to address global climate change.

4.1.1 What are alternative fuel vehicles? (p.88)

vehicles that do not run solely on gasoline or diesel.

4.2.3 What are the projected results of the standards? (p.96)

• • Cut 6 billion metric tons of GHG over the lifetimes of the vehicles sold in model years 2012-2025; • Save families more than $1.7 trillion in fuel costs; and • Reduce America's dependence on oil by more than 2 million barrels per day in 2025.

4.1.3 What advanced technologies do hybrid-electric vehicles use? (p.88)

• Battery Pack and Generator • Regenerative Braking • Electric Motor Drive/Assist The electric motor provides additional power to assist the engine in accelerating, passing, or hill climbing. • Automatic Start/Shutoff Automatically shuts off the engine when the vehicle comes to a stop and restarts it when the accelerator is pressed

4.7.1 What are the benefits of reducing the duration of engine idling? (p.115-116)

• Decreasing fuel costs • Decreasing engine maintenance costs • Extending engine life • Improving operator well-being by decreasing noise levels • Decreasing emissions that are harmful to the environment.

4.7.2 What are the two ways of reducing idling? (p.116)

• Modified driver behavior • Idling reduction technologies, which are assessed and verified by EPA

4.7.10 What does a TES systems economic performance depend on? (p.118)

A TES system's economic performance depends substantially on its specific application and operational needs, including the number and frequency of storage cycles. In general, PCM and TCS systems are more expensive than sensible heat systems and are economically viable only for applications with a high number of cycles. In mature economies (e.g. OECD countries), a major constraint for TES deployment is the low construction rate of new buildings, while in emerging economies TES systems have a larger deployment potential.

4.4.5 What is a Diesel Particulate Filter (DPF)? (p.109)

A diesel particulate filter (or DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine

4.1.18 What is a Flex-Fuel vehicle? (p.95)

A flexible-fuel vehicle is designed to run on gasoline or a blend of up to 85 percent ethanol. This mixture is referred to as gasohol and labeled with an "E" followed by the percentage of ethanol.

4.6.1 How common are Propane powered vehicles? (p.114)

According to the Propane Education and Research Council, there are more than 143,000 on-road propane vehicles in the United States. Many are used in fleet applications, such as school buses, shuttles, and police vehicles

4.7.15 How can Electrified Parking Spaces reduce emissions and benefit truck operators? (p.120)

Electrified parking spaces (EPS), also known as truck stop electrification (TSE), provide truck drivers the necessary services, such as heating, air conditioning, or appliances, without requiring them to idle their engine. Since it's three times harder on an engine to idle than to pull a load, it can be very beneficial for the trucks. While there is no limit to the length of time a truck can access power, a lack of adequate infrastructure has prevented widespread adoption of this technology. Truck stop electrification can reduce diesel emissions and save on fuel costs (costing about $2 an hour to run), although there are indirect impacts associated with the method of electricity generation

4.3.5 What is Electronic Fuel Injection? (p.105-106)

Electronic fuel injection (EFI) replaced carburetors back in the mid-1980s as the preferred method for supplying air and fuel to engines..

4.7.16 What is Single-System Electrification? (p.120)

In single-system electrification, off-board equipment at the truck stop provides internet, heating, ventilation, and air conditioning (HVAC). These HVAC systems are contained in a structure above (called a gantry) or on a pedestal beside the truck parking spaces. A hose from the HVAC system is connected to the truck window and, in some cases, to a computer touch screen that enables payment.

4.1.4 What is a "Mild" Hybrid vehicle? (p.88)

It uses automatic engine shut-off/startup technology to marginally improve fuel economy. In addition to restarting the engine, a large battery pack under the rear seat powers 20-amp AC outlets under the rear seat and in the bed

4.6.3 How costly are propane powered vehicles to maintain? (p.114)

Lower maintenance costs are a prime reason behind propane's popularity for use in delivery trucks, taxis, and buses. Propane's high-octane rating (104 to 112 compared with 87 to 92 for gasoline) and low carbon and oil contamination characteristics have resulted in documented engine life of up to two times that of gasoline engines.

4.7.12 What are the costs and performance of available TES systems? (p.119)

TES systems based on sensible heat storage offer a storage capacity ranging from 10-50 kWh/t and storage efficiencies between 50-90%, depending on the specific heat of the storage medium and thermal insulation technologies. Costs of latent heat storage systems based on PCMs range between €10-50/kWh while TCS costs are estimated to range from €8-100/kWh. The economic viability of a TES depends heavily on application and operation needs, including the number and frequency of the storage cycles

4.7.13 What are some barriers to market entry that TES systems face? (p.119)

TES technologies face some barriers to market entry. In most cases, cost is a major issue. Storage systems based on TCS and PCM also need improvements in the stability of storage performance, which is associated with material properties.

4.4.9 What is the National Vehicle and Fuel Emissions Laboratory (NVFEL)? (p.110)

The National Vehicle and Fuel Emissions Laboratory (NVFEL) leads the development of science and research in support of EPA's regulations in the transportation sector.

4.7.11 What TES storage mediums available? (p.118)

The most popular and commercial heat storage medium is water, which has several residential and industrial applications. Underground storage of sensible heat in both liquid and solid media is also used for typically large-scale applications. However, TES systems based on sensible heat storage offer a storage capacity that is limited by the specific heat of the storage medium. Phase change materials (PCMs) can offer a higher storage capacity that is associated with the latent heat of the phase change. PCMs also enable a target-oriented discharging temperature that is set by the constant temperature of the phase change.

4.2.15 How does the proposed HD National Program provide flexibility to manufacturers to comply? (p.99)

The primary proposed flexibility provisions are an engine averaging, banking, and trading (ABT) program and a vehicle ABT program. These ABT programs would allow for emission and/or fuel consumption credits to be averaged, banked, or traded within each of the regulatory subcategories; however, it is proposed that credits would not be allowed to be transferred across categories. In addition to the general ABT programs, EPA is proposing to allow engine manufacturers the added option of using CO2 credits to offset CH4 or N2O emissions that exceed the applicable emission standards based on the relative global warming potentials of these emissions

4.7.8 What are the three types of TES systems? (p.117)

There are three kinds of TES systems, namely: 1) sensible heat storage that is based on storing thermal energy by heating or cooling a liquid or solid storage medium (e.g. water, sand, molten salts, rocks), with water being the cheapest option; 2) latent heat storage using phase change materials or PCMs (e.g. from a solid state into a liquid state); and 3) thermo-chemical storage (TCS) using chemical reactions to store and release thermal energy.