Specific-Heat-Specific-Gravity

viscosity_and_specific_gravity

Kasinathan

In a diesel engine fuel injection system for automobiles and industrial machines, a pump, which injects fuel with a plunger, is generally used.  This type of pump is classified as follows.

In line type pump -

The same number of plungers as engine cylinders are aligned in series in the pump

Distributor type pump

One plunger distributes fuel into each cylinder.

Camshaft-less type pump

Same as the in-line type pump, the camshaft-less (PFR) type pump does not have a camshaft.

CHARACTERISTICS & PURPOSE OF EACH TYPE OF PUMP

a.         In Line Type Fuel Injection Pump

In-line type injection pump

Consists of pump main body, governor, feed pump and timer.  It has the same number of plungers as cylinders of the engine and supplies fuel to all cylinders with one rotation of the
camshaft.

As this type of pump has the longest history of usage, it is widely used.It is now common in middle and large size trucks, agricultural machines and construction machines, while the distributor type is taking over for small engines.

b.         The Distributor Type Fuel Injection Pump (VE Type)

The distributor type pump was developed in response to the demand for lighter, more compact
pumps for the smaller car engines now available.

This type of pump injects and distributes the fuel into each cylinder with one rotation of
a plunger.  Because components such as governors, feed pump and timer are built into the pump
body, this pump is suited to mass production.

c.         Camshaft-Less (PFR) Type Fuel Injection Pump

The principle behind the PFR type and In-Line type pump is the same. However, in the PFR type,
the camshaft and governor function are on the engine side for a more compact system.

This type of pump is used for agricultural machines and construction machines that
require simple control.

Current pump type:

DISTRIBUTOR TYPE FUEL INJECTION PUMP – ELECTRONICALLY CONTROLLED – OVERVIEW

The electronic control system of the distributor type pump consists of various sensors, an ECU (computer) and actuators. The DENSO DFI pumps commonly used in Australia at present are the ECD-V3 and ECD-V4 which are both electronically controlled distributor types.

Sensors detect the running condition of the engine or pump

The ECU (Electronic Control Unit) receives input signals from various sensors and
then calculates and controls the output signals for factors such as timing, volume and pressure.

Actuators control injection quantity and injection timing according to the signal sent from the ECU.

I

COMMON RAIL TYPE FUEL INJECTION PUMP -

Common Rail Injector Functional Video

CRDI Video

Increasingly stringent emission regulations will be impossible to meet with

conventional diesel systems.  With their greater accuracy and reduced emissions,

Common rail injection systems will be instrumental in engineering diesel engines that will comply with future emission regulations.

Injection parameters are very important for diesel power.  Injection pressure is much higher, with multiple, precisely controlled injections at each combustion stroke.  With common rail technology, the quantity, timing and pressure of injections are
controllable separately.  This allows for more precise fine-tuning of engine
performance than with petrol systems.

The common rail type system is completely different than conventional fuel injection
pumps. With previous pumps, fuel is distributed from the high pressure pipe to each
cylinder.  With this system, high pressure fuel is accumulated at a common rail.  This
eliminates the need for a fuel force-feed system based on the number of cylinders.

The supply pump draws the fuel up from the tank for force-feeding to the common rail, until the required common rail pressure is reached. An injector mounted on each cylinder then distributes the high-pressure fuel to each injector via the common rail. The ECU controls fuel delivery timing and amount.

Common Rail fuel system

EDU (Electronic Driving Unit)

CDI type high voltage driver.  It is used for high speed driving of the electromagnetic spill valve that works under high pressure. The EDU allows precise control of the
injection timing of highly pressurised and finely atomised fuel which decreases
emissions.

EGR Control

Controls exhaust gas by recirculating it into the gas intake manifold to suppress combustion and therefore reduce emissions (NOx).

Governor

Automatically controls the engine speed and output by adjusting the fuel injection quantity in accordance with the load on the engine, and the amount that the
accelerator pedal is depressed.

SPV – Solenoid Spill Valve

Highly pressure resistant and responsive, the solenoid spill valve is a direct-acting

solenoid valve that controls the injection volume.  When the solenoid spill valve

opens, the highly pressurised fuel in the plunger returns to the pump chamber, ending the injection of fuel.

It is a unique design that uses two counter rotating tri lobular cams and rollers to produce the reciprocating motion normally generated by a crankshaft and connecting rod in a conventional engine.   The Tri-lobed cam profile can be tailored to generate different piston motions with respect to crank angle.   

V2 - Tri-Lobe Cam Mechanism

  While the configuration of the reciprocating mechanism of the engine is not reported here, it should be noted that the cylinder head configuration can be described as a conventional over head valve configuration with 2 valves per cylinder operated by a conventional camshaft, push rod and rocker arm system.   Each cylinder head utilised two spark plugs per cylinder.

Why is the need of Engine Brake (Retarder)?

Roads & Loads

No one can afford to run an empty truck. However, by maximizing truck’s load, minimizing control of the vehicle is necessary.

Productivity

A retarder allows for faster safe descents, reducing trip times, thus increasing productivity.

Lowers Costs

Supplementing the vehicle’s braking system drastically extends the service brakes and wheel-end life, and keeps brake temperatures cool and in reserve for stopping needs, when we brake the most. Therefore, associated downtime and costs of wheel-end repairs and brake maintenance are significantly reduced. Further, the cost to purchase a vehicle with an engine retarder is lower than if the same vehicle were equipped with a hydraulic or electric retarder.

Driver Satisfaction

Drivers all over the world request Jake Brake retarder because of the enhanced control of the vehicle and reduced driving fatigue benefits.

The effectiveness of a Jake Brake® retarder is shown in the calculation below. In the example below, the vehicle is equipped with a Jake Brake retarder and is loaded to 34 metric tonnes (~75,000 lbs). This vehicle will produce sufficient engine retarding horsepower to allow the vehicle to maintain a constant downhill control speed on a 6% slope – without use of the service brakes.

Jake Engine Brake

Jacobs Vehicle Systems^TM (www.jakebrake.com–a wholly-owned subsidiary of Danaher Corporation – NYSE: DHR) announced the expansion of its technology-leading product line with the launch of the Model 965 integrated engine subsystem for Hino Motors Ltd. of Japan. The Model 965 will supply the valve timing for both retarding and Internal Exhaust Gas Recirculation (IEGR) for Hino’s new E13C on-highway truck diesel engine, which launches this fall in Japan.

Success Through Mutual Cooperation

The 965 is the result of close coordination between Hino Motors Ltd. of Japan, and Jacobs Vehicle Systems of the U.S.A. “Through close cooperation between Hino Motors and Jacobs, we have been able to design and manufacture a valve motion system to support Hino’s engine retarding and emissions needs in one compact, robust product” states Vice President of Marketing, Bob Perkins. “The result is a true breakthrough in engine system optimization.”

Emissions & Retarding Coupled

IEGR (Internal Exhaust Gas Recirculation) can provide a significant reduction in diesel engine nitrous oxide (NOX) emissions. It is an attractive alternative and/or supplement to cooled-EGR, benefiting from lower initial cost, enabled by streamlined packaging, reduced weight and reduced cooling demands for the engine.

CRR (Compression-Release Retarding) provides vehicle, retarding capability utilizing the diesel engine as an air compressor to improve vehicle slowing and control. This function significantly reduces wear of the service brakes and contributes to improved drivability of the vehicle.

Since both the IEGR and the CRR systems utilize the engine’s exhaust valves, the common operating system was a natural development for Jacobs, a world leader in valve movement. Jacobs has utilized its proven Jake Brake design and manufacturing technology to help meet Hino’s very high reliability goals for this new emissions technology.

Jacobs Engine Brakes on certain engines are more powerful than on others.

Jacobs Engine Brakes are designed for specific engine applications, and retarding performance will vary depending on several factors of the design. One thing that is common to all engine brakes is that retarding horsepower increases as engine RPM increases. Optimum performance of the engine brake is achieved near rated engine RPM. In general, the same things that affect positive power influence retarding power. The most important factors affecting retarding performance are engine displacement, compression ratio, turbo type, level of boost, and the timing of the valve-opening event. Lets look in detail at how these factors affect the brake performance.

In it’s simplest description, the Jacobs Engine Brake converts a diesel engine into an air compressor. All other factors being equal, the larger the engine displacement, the more powerful an air compressor it can make, and the higher the retarding performance.

Compression ratios of diesel engines are typically around 15:1. At the top of the piston stroke the air will occupy 1/15th the original volume, and be at around 500 psi. It takes power to compress air to high pressures; the engine crankshaft supplies this power. Higher compression ratios produce higher cylinder pressures, and absorb more power in doing so.

If the turbo is able to provide more boost, the starting volume of air will be at a higher initial pressure. This will result in a much higher final pressure. The higher the final pressure, the more power is absorbed. A turbo that produces higher boost pressures would result in higher retarding performance.

(NOTE: Do not try to modify turbocharger to provide more boost for braking performance. The result will include a shattering/popping sound through the exhaust, turbocharger damage, as well as engine and engine brake damage. Doing so will void engine and brake warranties.)

Variable Geometry Turbochargers (VGT) or Variable Nozzle Turbine (VNT) turbocharger technology provides boost at lower RPMs, and increase mid range RPM performance of the engine brake.

Without an engine brake, all the valves remain closed at the top of the compression stroke, and we start the power stroke. In a no-fuel condition, the air pressure exerts a force on the piston and returns most of the power to the crankshaft. With a Jacobs Engine Brake active, the exhaust valves are opened, close to top dead center of the compression stroke. “Pop” goes the energy stored in the air, safely out through the exhaust system. Theoretically, none of the power is returned to the crankshaft, and the engine is able to provide retarding power for the vehicle.

The timing of the valve-opening event is important because the piston at top dead center has done the maximum amount of work. If the valve is opened early, engine will not have absorbed as much power. Similarly, if the valve is opened after top dead center, some power has been returned to the crank by the compressed air. As the valve-opening event moves away from top dead center, the brake becomes less effective. In practice it is necessary to use a cam or rocker motion that occurs close to top dead center. This motion will be picked up by a master piston and transmitted through a hydraulic circuit to a slave piston to open the exhaust valve.

Jacobs Engine Brakes are designed using injector, exhaust, intake rockers or the camshaft directly to time the opening of the exhaust valve. Most engine brakes for Cummins and Detroit Diesel engines as well as Caterpillar 3406E/C15/C16 engines utilize injector timing, where the master piston follows the injector rocker for the same cylinder. On older Cat 3406,3406B and 3406C engines, and Mack E6 and E7, the slave piston for one cylinder is controlled by a master piston following an exhaust valve of another cylinder. This doesn’t provide optimum timing or rate of valve opening, and the hydraulic circuits are longer and don’t respond as well. Today’s Mack E7 E-Tech^TM engine was designed with the engine brake in mind from the beginning.

The specific design considerations of a particular engine significantly affect the retarding performance of the engine brake. It is also important to consider the load constraints of the engine components and the engine brake housings, as well as required valve to piston clearance. The retarding performance in a vehicle is also affected by many factors including the transmission, rear axle ratio, tire size, and vehicle dynamics.

How does the engine brake control valve motion?

A standard technology engine brake consists of a solenoid valve, control valve, and master and slave pistons. These components are assembled into a housing as shown below.

How are engine brakes controlled?

Typically, under good road conditions, the driver enables the retarder and selects a level of retarding with selector switches on the dash. To activate the brake, two more conditions must be met: clutch is engaged (or automatic transmission is in lock-up), and no fuel to the engine (foot off the pedal). Under these conditions, voltage is applied to the engine brake solenoids, and the brake is activated.

On older engines with mechanical fuel control, the Jacobs Engine Brake control system includes fuel pump and clutch switches in addition to the dash switches to detect when the required conditions were met. Today’s electronic engines have an engine control module (ECM), which knows when there is a no fuel condition, and gets inputs if the clutch is engaged. For electronic engines the engine brake is powered directly by the engine control module.

All engine brake control systems can be configured to work with a vehicle’s ABS brake system, and most can be configured to work with cruise control. Many of today’s electronic automatic transmissions can be programmed to downshift if the retarder is requested, allowing the optimum RPM to be obtained and maintained for the best engine brake performance.

If Engine Brake stopped working, what’s the most likely problem?

Generally if engine brake stopped working entirely, then it may have an electrical problem. This is most likely a failed switch (probably a fuel pump or clutch switch). Confirm this by hot-wiring the brake i.e. bringing battery power directly to the solenoid leads (with the engine at idle). Be sure to disconnect the existing leads to the solenoids so that it does not damage control system.

If the brake does not operate when hot-wired, it may have a solenoid failure. If the solenoid is actuating but the brake is not turning on, the problem is probably mechanical.

If Engine Brake doesn’t seem to have the retarding power it used to, what’s the most likely cause?

There are a number of things that may affect engine brake performance, and a qualified service technician is best suited to find the cause. In general the same factors that affect positive power performance affect retarding as well.  Always check positive power performance before looking at a retarding performance problem.

Assuming engine is functioning as specified in positive power there may be a problem with the engine brake or its control signal. If the brake was functioning well before, the first thing a technician will do is check to see if all of the housings are working. It may simply be a housing with a loose wire or faulty solenoid.

Assuming the housings are being activated, the slave piston lash adjustment will be the next thing to check. Don’t be fooled into thinking that going tighter or looser on the adjustment will give more performance – in most cases this simply isn’t the case, and engine or housing damage could result.

If the adjustments are correct and all the housings are turning on as required, it’s time for more detailed investigation – and this gets into the specifics of each model.

Hino Combined EGR System with Jake Brake

Jake IEGR – An OVERVIEW

Fifty years ago, Clessie Cummins believed the diesel engine could be used on “both sides of the hill.” From that idea, the Jake Brake® engine brake was born.

About ten years ago, Jake began to test theories of utilizing the precise valve actuations used in the engine brake on both sides of the hill. As a result, Jacobs variable valve actuation (VVA) was inspired. This research, combined with over forty years of precision valve actuation expertise, has yielded a NOx reduction solution, which provides Internal Exhaust Gas Recirculation (IEGR) by altering engine valve lift. Jacobs IEGR reduces peak combustion temperatures and, therefore, reduces the formation of Nitrogen Oxides (NOx) to levels acceptable to meet upcoming emissions standards. Jacobs IEGR utilizes proven, reliable components and functional product designs mastered by Jacobs with its well-known Jake Brake® engine brakes. With over 3,000,000 engine brake systems sold and over 2.7 Trillion kilometers of road experience with precision valve actuation, the Jacobs IEGR system design is a solution you can trust.

Additionally, relative to other NOx reduction technologies, the Jacobs IEGR system is a very attractive option. The system is compact, mounting directly to the engine overhead with minimal added weight and height. An engine packaged with Jacobs IEGR will require little to no modification without increasing radiator capacity. Engine serviceability is not compromised, and operation is transparent to the driver. If desired, an engine braking function can be integrated into the Jacobs IEGR product. When compared to other NOx reduction options, the cost of Jacobs IEGR system is very competitive.

Reliable, cost-effective NOx reduction technology is ready to help your engines meet upcoming tailpipe emissions for diesel engines. Turn to the experts the diesel industry has come to for over forty years. Turn to Jacobs.

BENEFITS

• Reduced formation of Nitrogen Oxides (NOx)
• Helps meet the latest emissions standards
• Utilizes proven, reliable components and functional product designs
• Compact design with minimal added weight and height
• Engines require little to no modification
• Over forty years of precision valve actuation expertise

- content provided by Mr. Vinod.. from Middle East country

While some of these technologies are affected less by the sulfur content of diesel fuel, all perform better at reducing emissions when used with ultra-low sulfur diesel fuel (ULSD), which has a sulfur content of less than 15 ppm. For example, diesel oxidation catalysts and some DPFs can reduce CO, HC, and PM emissions with fuels that contain sulfur levels greater than 15 ppm while catalyst-based DPFs are more sensitive and are more effective with ULSD. (See the insert on “Alternative Fuels” for more information.)

Costs for individual technologies vary. This insert cites costs from an independent cost survey conducted in November 2000 by the Manufacturers of Emission Controls Association (MECA). Generally, the larger the engine being retrofitted, the more expensive the device. However, higher sales volumes will begin to lower the costs of these technologies. Given the recent market penetration, costs should begin to decrease. Prices cited in association with specific technologies and their pollution reduction potential are provided by the U.S. Environmental Protection Agency (EPA). The reader is encouraged to contact individual manufacturers for exact costs.

Diesel Particulate Filters (DPF)

Diesel particulate filters (DPFs) are one class of emission control technologies that lower PM emissions. By trapping the particulates as the exhaust gas passes through the filter, DPFs are able to achieve PM reductions of 80 – 90 percent. Numerous studies have documented the effectiveness of DPFs in both on- and off-road applications. The systems are relatively easy to maintain, but do require users to monitor their condition and occasionally remove the filter, blowing out the ash and replacing it.

Fuel sulfur content plays a key role in the performance of DPFs since it has a direct impact on the level of particulate matter in the exhaust. Numerous studies have found that DPFs, regardless of their manufacturer, achieve higher PM emission reductions with the use of ultra-low sulfur diesel fuel.

Two DPF products – Engelhard’s DPX Catalyzed DPF and the Johnson Matthey Continuously Regenerating Technology (CRT) Particulate Filter – reduce PM, CO, and HC by 60 percent as verified – but are capable of reducing emissions by 80 – 90 percent. Both technologies are verified by EPA’s National Voluntary Diesel Retrofit Program – which tests and validates technologies for fleet managers and operators – for their performance. These products are verified with ULSD. Today’s technology could be utilized in many off-road applications but requires active regeneration technology being developed for on-road use to make it applicable to all off-road applications. DPF retrofit programs for trucks and buses are underway in California and New York City, where the city plans to retrofit its 3,500 buses with DPFs by the end of 2003.

Diesel Oxidation Catalysts (DOC)

Diesel oxidation catalysts (DOCs) are a section of the exhaust system coated with metals that trigger chemical reactions which breakdown pollutants (CO, HC, PM) into harmless gases, when engine exhaust passes through it. Since 1995, more than 500,000 trucks and buses have been retrofitted with DOC systems.

On- and off-road applications of DOCs are virtually maintenance free, requiring only periodic inspections. DOCs also work to improve the effectiveness and performance of DPFs, by attracting excess soot from the exhaust before it passes through the filter. The cost of diesel oxidation catalyst devices range from several hundred to several thousand dollars per device depending on engine size, sales volume, and whether the installation is a muffler replacement or an in-line installation. MECA’s 2000 survey reported that average diesel oxidation catalyst costs ranged from $465 to $1,750 per vehicle. The majority of devices are designed to replace the muffler and installations typically take less than two hours.

Like DPFs, DOCs are also affected by sulfur. The sulfur content of diesel fuel is critical to applying catalyst technology, as the reaction caused by the catalysts rely on the sulfur content and the temperature of the exhaust gases.

NOx Reduction Technologies

The first verified system to reduce NOx and PM is a NOx reduction catalyst. This system combines a NOx catalyst with a particulate filter or oxidation catalyst to provide additional PM reductions. The Longview system from Cleaire (and offered by Fleetguard Emission Solutions) is verified to reduce NOx by 25 percent and PM by 85 percent.

In addition to the exhaust gas recirculation (EGR) technology to lessen NOx during the combustion process (see the insert on “Advances in Diesel Engine Technology” for more information), post-combustion emission controls for NOx include selective catalytic reduction (SCR) and NOx adsorber technologies.

SCR devices have been used for years to control NOx from stationary sources and are now being applied to mobile sources to cut the pollutant by over 70 percent. Unlike DOCs, the SCR system requires the addition of a reductant (typically urea or ammonia) to convert NOx pollutants to nitrogen and oxygen. Based on the oxidizing metals used in the SCR, additional pollutant reductions can be achieved. (See the insert on “Off-Road Heavy-Duty Diesel Vehicles” for more information.)

NOx adsorber catalyst technology is also undergoing extensive research and development in anticipation of the 2007 on-road, heavy-duty diesel engine regulations. Researchers have demonstrated the ability of NOx adsorbers to control up to 90 percent or more of NOx emissions over a broad temperature range.

NOx adsorbers act to store NOx emissions during lean engine operation and release the stored NOx by periodically creating a rich exhaust environment by either engine operation or the injection of a reductant in the exhaust stream. While EPA estimates that the technology can cut NOx (as well as HC and CO) by more than 90 percent, it is still largely in the research and development phase for on-road applications.

Crankcase Emission Control

In the majority of turbo-charged diesel engines, the crankcase breather is vented to the atmosphere often using a downward directed draft tube, therefore allowing a substantial amount of PM to be released into the atmosphere. One solution to this emissions problem is the use of a multi-stage filter designed to collect and return the emitted lube oil to the engine’s sump or a CCV system (available from Fleetguard). These systems allow filtered gases to return to the intake system, balancing the differential pressures involved and allowing the systems to eliminate crankcase emissions. EPA has verified one manufacturer’s crankcase filtration system. In addition to the Donaldson closed crankcase filtration system’s ability to lower crankcase emissions, it also reduces PM emissions by 25 – 32 percent and CO by 14 – 18 percent, according to EPA.

Additional Technology Potential

The California Air Resources Board recently verified the use of a diesel engine retrofit technology that simultaneously achieves reductions of at least 85 percent in PM and 25 percent in NOx emissions. The system produced by Cleaire Advanced Emission Controls is actually a combination of a lean NOx catalyst and a diesel particulate filter. The system has been verified for use on specific on-road diesel engines operating on ultra-low sulfur diesel fuel. In addition to DOC technology used to treat exhaust gases, EPA estimates that catalysts included in diesel fuel for commercial use will cut NOx up to 10 percent, PM up to 33 percent, and HC and CO up to 50 percent during the combustion process.

The Lubrizol Corporation has developed a water-in-diesel fuel emulsion product that produces a low-emission, emulsified diesel fuel. PuriNOx reduces NOx emissions up to 30 percent and PM up to 65 percent when compared to conventional No. 2 diesel fuel. Average emission reductions, considering data from numerous tests, indicate a NOx reduction of approximately 20 percent and a PM reduction of approximately 54 percent. The application areas for fuel powered by PuriNOx are centrally-fueled fleets, such as pick-up and delivery vehicles, urban and school buses, waste management fleets, and agricultural, mining, and construction equipment.

Driven in large part by upcoming U.S. Environmental Protection Agency (EPA) regulations, fleet managers, maintenance technicians, truck drivers and engine manufacturers have developed a variety of emission-reduction technologies to minimize diesel emissions before the standards begin to take effect within the next few years.

The new EPA regulations target reductions of both particulate matter (PM) and nitrogen oxide (NOx) by 98 percent from 1988 levels – virtual elimination of these emissions from on-road engines. Similar requirements were proposed in April 2003 for off-road diesel vehicles, such as those used in construction, agricultural, and industrial applications. (See the insert on “Off-Road Heavy-Duty Diesel Vehicles” or “Diesel Emission Standards for Heavy-Duty On- and Off-Road Engines” for more information.)

In both cases, the regulations entail the use of new technologies to lessen the production of pollutants from combustion – such as engine design and fuel – and to minimize the amount of post-combustion pollutants released into the air. (See the insert on “Emission Control Technologies” for more information.) This insert summarizes the assortment of emission-reduction technologies available today and discusses recent advances in diesel fuel and engines.

Exhaust Gas Recirculation (EGR)

Nitrogen oxide (NOx) is formed as a by-product of high combustion temperatures. One common approach for lowering NOx emissions from diesel engine combustion is to utilize exhaust gas recirculation (EGR) technology. EGR involves recirculating a portion of the engine’s exhaust back to the engine at a lower temperature. The cooled gases have a higher heat capacity than air and contain less oxygen than air such that when it is reused, it lowers the temperature of combustion and subsequently reduces the formation of NOx.

Common-Rail Fuel Injection

Common-rail fuel injection is an advanced fuel pump technology that allows the use of higher injection pressures than systems incorporating conventional pumps. The use of a common rail from which the injectors are directly fed allows the pressure and injection timing to be precisely controlled by electronic means. By directly feeding the injectors from a single fuel pump, the electronic system optimizes the amount of fuel pressurized prior to injection.

This extremely high pressure allows finer vaporization of the fuel droplets, which means a far more homogenous mixture with the air in the cylinder. Therefore, combustion is more complete and exhaust emissions are reduced.

Combustion Chamber Design

In addition to improving the efficiency, effectiveness, and performance of the combustion process, engineers have also made advances in the configuration of the combustion chamber. By designing the chamber to have the correct configuration for the most effective combustion of the air and fuel mixture, the engine maximizes its power output at each stroke, maximizes fuel efficiency, and reduces combustion emissions.

Turbocharging

Unlike EGR, where a portion of the exhaust gases are used again in the combustion, turbocharging utilizes energy from the engine exhaust to boost performance by using it to drive a turbine wheel that turns a second turbine wheel, which forces more air into the cylinder. Forcing more oxygen into the chamber increases the efficiency of the combustion process, reduces emissions, and increases performance. Turbocharging technology is particularly beneficial in Colorado as heavy-duty trucks traverse mountain passes with lowered oxygen levels.

Electronic Engine Controls

Innovative computer technology and software used to monitor factors affecting diesel engine performance such as oxygen, combustion chamber, and exhaust temperatures, levels of NOx and other pollutants, play a key role in the success of some of the technologies discussed here and in other diesel technology inserts. For example, computers monitor the performance of EGR and the fuel injection process to maximize combustion efficiency.

Diesel Fuel

The sulfur content of diesel fuel in Colorado and much of the rest of the country is at approximately 300 parts per million (ppm) for on-road vehicles. EPA regulations, however, will necessitate that owners and operators begin using reduced sulfur content diesel. California already requires the use of highly-refined, ultra-low sulfur diesel fuel (ULSD) in many applications. ULSD has a sulfur content of up to 15 ppm, a 99 percent reduction. The ULSD fuel is currently available in California, Pennsylvania, and the Northeast, but refiners expect the fuel to be available nationwide by 2006 as the new EPA requirements begin. (See the insert on “Diesel Emission Standards for Heavy-Duty On- and Off-Road Engines” for more information.)

Because of the low sulfur content, fewer PM emissions are generated during the combustion process. At the same time, the fuel improves the effectiveness of post-combustion emission control technologies when they are used. (See the insert on “Emission Control Technologies” for more information.)

Case Studies/Success Stories

A 1999 test program initiated by the Manufacturers of Emission Control Technologies (MECA) used both standard diesel fuel (sulfur content of 368 ppm) and ULSD in a typical on-road, heavy-duty diesel engine to evaluate the performance of diesel particulate filters (DPFs), diesel oxidation catalysts (DOCs), selective catalytic reduction (SCR), and fuel-borne catalysts. The organization’s findings (supported by additional industry and government research) demonstrated that commercially available emission control technologies can significantly reduce PM and other pollutants and that the performance of the technologies are substantially improved with the use of ULSD.

Industry leaders in promoting clean diesel technologies include Bosch, BP, Caterpillar, Cummins, Detroit Diesel, Eaton, Exxon Mobil, Garrett, General Motors, International, Isuzu, Johnson Matthey, and Komatsu.

Concept Car Image Gallery

Photo courtesy Moller International
You’re bound to turn some heads in a Moller M400. See moreconcept car pictures.

Traffic jams are the bane of any commuter. Many of us spend an hour or so stuck in traffic every week. The growing population is partly to blame for our congested roads, but the main problem is that we are not expanding our transportation systems fast enough to meet ever increasing demands. One solution is to create a new type of transportation that doesn’t rely on roads, which could one day make traffic jams a 20th century relic. To do this, we must look to the sky.

In the last century, airplanes and mass- produced cars have changed the way we live. Cars, which became affordable for the general population, have allowed us to move farther away from cities, and planes have cut travel time to faraway destinations considerably. At the beginning of a new century, we may see the realization of a century-old dream — the merging of cars and planes into roadable aircraft, or flying cars. You’ve probably heard promises about flying cars before, and the technology to make them safe and easy to fly may finally be here.

History of Flying Cars

Just a decade and a half after the Wright Brothers took off in their airplane over the plains of Kitty Hawk, N.C., in 1903, other pioneering men began chasing the dream of a flying car. There was even one attempt in the 18th century to develop a gliding horse cart, which, to no great surprise, failed. There are nearly 80 patents on file at the United States Patent and Trademark Office for various kinds of flying cars. Some of these have actually flown. Most have not. And all have come up short of reaching the goal of the mass-produced flying car. Here’s a look back at a few of the flying cars that distinguished themselves from the pack:

• Curtiss Autoplane - In 1917, Glenn Curtiss, who could be called the father of the flying car, unveiled the first attempt at such a vehicle. His aluminum Autoplane sported three wings that spanned 40 feet (12.2 meters). The car’s motor drove a four-bladed propeller at the rear of the car. The Autoplane never truly flew, but it did manage a few short hops.
• Arrowbile - Developed by Waldo Waterman in 1937, the Arrowbile was a hybrid Studebaker-aircraft. Like the Autoplane, it too had a propeller attached to the rear of the vehicle. The three-wheeled car was powered by a typical 100-horsepower Studebaker engine. The wings detached for storage. A lack of funding killed the project.
• Airphibian - Robert Fulton, who was a distant relative of the steam engine inventor, developed the Airphibian in 1946. Instead of adapting a car for flying, Fulton adapted a plane for the road. The wings and tail section of the plane could be removed to accommodate road travel, and the propeller could be stored inside the plane’s fuselage. It took only five minutes to convert the plane into a car. The Airphibian was the first flying car to be certified by the Civil Aeronautics Administration, the predecessor of the the Federal Aviation Administration (FAA). It had a 150-horsepower, six-cylinder engine and could fly 120 miles per hour and drive at 50 mph. Despite his success, Fulton couldn’t find a reliable financial backer for the Airphibian.
• ConvAirCar - In the 1940s, Consolidated-Vultee developed a two-door sedan equipped with a detachable airplane unit. The ConvAirCar debuted in 1947, and offered one hour of flight and a gas mileage of 45 miles (72 kilometers) per gallon. Plans to market the car ended when it crashed on its third flight.
• Avrocar - The first flying car designed for military use was the Avrocar, developed in a joint effort between Canadian and British military. The flying-saucer-like vehicle was supposed to be a lightweight air carrier that would move troops to the battlefield.
• Aerocar - Inspired by the Airphibian and Robert Fulton, whom he had met years before, Moulton “Molt” Taylor created perhaps the most well-known and most successful flying car to date. The Aerocar was designed to drive, fly and then drive again without interruption. Taylor covered his car with a fiberglass shell. A 10-foot-long (3-meter) drive shaft connected the engine to a pusher propeller. It cruised at 120 mph (193 kph) in the air and was the second and last roadable aircraft to receive FAA approval. In 1970, Ford Motor Co. even considered marketing the vehicle, but the decade’s oil crisis dashed those plans

These pioneers never managed to develop a viable flying car, and some even died testing their inventions. However, they proved that a car could be built to fly, and inspired a new group of roadable aircraft enthusiasts. With advances in lightweight material, computer modeling and computer-controlled aircraft, the dream is very close to becoming reality. In the next section, we will look at the flying cars being developed today that eventually could be in our garages.

Modern Flying Cars

When George Jetson first flew across American TV screens in his flying car-like vehicle in 1962, many of us began wondering when we could buy our own Supersonic Suburbanite or Spacion Wagon. Amazingly, that day may be around the corner. After a century of unfulfilled promises, flying cars may fill the skies in the next few decades. There are still some obstacles to overcome, including receiving approval from the FAA, but the cars are close to being finished. 

Photo courtesy Moller International The M200X, the predecessor of the Skycar, flew for the first time in 1989 to a height of 50 feet.

There is no lack of engineers taking on the challenge to design a new breed of flying cars. While sleeker, more advanced cars have been developed in the last decade, no one has come close to opening up a flying car dealership. Here are a few of the individuals attempting to deliver a flying car:

• Paul Moller has spent 40 years and millions of dollars developing his Skycar. He is now very close to developing the first mass-marketed flying car. In 1965, he demonstrated his first attempt, the XM-2, which hovered off the ground but didn’t go anywhere. In 1989, Moller unveiled the M200X, which has now flown 200 flights and can go as high as 50 feet (15.24 meters).
• MACRO Industries in Huntsville, Ala., is developing a flying car that it’s calling the SkyRider X2R. This aero car will be able to take off and land vertically. SkyRider incorporates the interior design of a 2-seat sports car with the mobility of a helicopter or airplane. The company said it is also developing 5 and 7-seat models of the SkyRider, and it should fit in most two-car garages. The navigation system will be controlled almost entirely by GPS satellites and cellular services.
• In Israel, Dr. Rafi Yoeli of Urban Aeronautics is testing the CityHawk, a prototype of a fly-by-wire car. He’s also working on a project centered around the X-Hawk, a rotorless Verticle-Take-Off and Landing vehicle (VTOL). Visit this Web site for more information.
• In 1990, Kenneth Wernicke formed Sky Technologies to develop a small-winged flying car. His Aircar has flown at 200 to 400 mph (322 to 644 kph) and driven at 65 mph (105 kph). It’s also small enough to fit into an average parking space.
• Recently, Branko Sarh, a senior engineer at McDonnell Douglas Aerospace, has attempted to develop a flying car, called the Sokol A400, or Advanced Flying Automobile. Sarh designed a 4-passenger vehicle that would pop out telescoping wings at the push of a button.

Moller’s latest design, the Skycar M400, is designed to take off and land vertically, like a Harrier Jet, in small spaces. It can reach speeds of 400 mph (644 kph), but will cruise at around 350 mph (563 kph), and it has a range of 900 miles (1449 km). Gasoline, diesel, alcohol, kerosene and propane can be used to fuel the Skycar, and its fuel mileage will be comparable to that of a medium-sized car, getting 20 miles (32.2 km) to the gallon. The initial cost of a Skycar will be about $1 million, but once it begins to be mass produced that price could come down to as low as $60,000. 

Photo courtesy Moller International The Skycar will be operated completely by computer and guided by GPS satellites.

The four-seat Skycar is powered by eight rotary engines that are housed inside four metal housings, called nacelles, on the side of the vehicle. There are two engines in each nacelle so that if one of the engines in one of the nacelle fails, the other engine can sustain flight. The engines lift the craft with 720 horsepower, and then thrust the craft forward. The Wankel engine replaces pistons of a conventional engine with a single triangular rotor spinning inside an oval-shaped chamber, which creates compression and expansion as the rotor turns. There are three combustion chambers in the Wankel, with a crankshaft between them.

To make the Skycar safe and available to the general public, it will be completely controlled by computers using Global Positioning System (GPS) satellites, which Moller calls a fly-by-wire system. In case of an accident, the vehicle will release a parachute and airbags, internally and externally, to cushion the impact of the crash.

MACRO Industries’ SkyRider X2R will also use this fly-by-wire system to safely transport passengers to their desired destinations. Drivers will simply get in, turn on the power and enter the address or phone number of their destination. SkyRider will do the rest. MACRO said that the system will be almost fully automatic, but may allow some manual control. Commands will be entered just by telling the car what you want it to do.

According to their Web site, MACRO is shooting to have a working vehicle produced sometime in 2006. The company is planning to power the vehicle with an enhanced automobile engine to drive four-ducted fans. The unique feature of the SkyRider will be the company’s patented rotary cartridge valve, which is expected to increase fuel efficiency and reduce emissions.

The CityHawk is similar to the Skycar and SkyRider in that it also takes off and lands vertically. However, there are some key differences. The CityHawk will be powered by fans that are driven by four internal combustion engines. Much like in the Skycar, this redundancy of engines will allow the vehicle to land even if one of the engines is lost. The CityHawk is about the size of a Chevy Surburban, and will have cruising speeds of 90 to 100 miles per hour (145 to 161 kph). CityHawk developers say that it could be used as an air taxi, for news gathering and for traffic control.

The mass availability of flying cars could be very exciting or very scary, depending on how you look at it. If proper safeguards are put in place, they could be the answer to our ever-worsening traffic jams. Flying cars that can travel at hundreds of miles per hour would not only cut that rush hour commute to a few minutes, but it would allow us to live hundreds of miles farther from work and still make it to the office faster than by road-bound cars today.

How Compressed Air Can Fuel a Car

Pascal Guyot/AFP
Guy Negre of MDI shows off his first compressed air engine in 2005.

The laws of physics dictate that uncontained gases will fill any given space. The easiest way to see this in action is to inflate a balloon. The elastic skin of the balloon holds the air tightly inside, but the moment you use a pin to create a hole in the balloon’s surface, the air expands outward with so much energy that the balloon explodes. Compressing a gas into a small space is a way to store energy. When the gas expands again, that energy is released to do work. That’s the basic principle behind what makes an air car go.  

The first air cars will have air compressors built into them. After a brisk drive, you’ll be able to take the car home, put it into the garage and plug in the compressor. The compressor will use air from around the car to refill the compressed air tank. Unfortunately, this is a rather slow method of refueling and will probably take up to two hours for a complete refill. If the idea of an air car catches on, air refueling stations will become available at ordinary gas stations, where the tank can be refilled much more rapidly with air that’s already been compressed. Filling your tank at the pump will probably take about three minutes [source: Cornell].

The first air cars will almost certainly use the Compressed Air Engine (CAE) developed by the French company, Motor Development International (MDI). Air cars using this engine will have tanks that will probably hold about 3,200 cubic feet (90.6 kiloliters) of compressed air. The vehicle’s accelerator operates a valve on its tank that allows air to be released into a pipe and then into the engine, where the pressure of the air’s expansion will push against the pistons and turn the crankshaft. This will produce enough powerfor speeds of about 35 miles (56 kilometers) per hour. When the air car surpasses that speed, a motor will kick in to operate the in-car air compressor so it can compress more air on the fly and provide extra power to the engine. The air is also heated as it hits the engine, increasing its volume to allow the car to move faster [source: Cornell].

Air Car Advantages

Valery Hache/AFP
A look inside MDI’s AirPod One prototype.

One major advantage of using compressed air to power a car’s engine is that a pure compressed air vehicle produces no pollution at thetailpipe. More specifically, the compressed air cars we’re likely to see in the near future won’t pollute at all until they reach speeds exceeding 35 miles per hour. That’s when the car’s internal air compressor will kick in to achieve extra speed. The motor that runs this air compressor will require fuel that’ll produce a small amount of air pollution. Some fuel (you can use eco-friendly biofuels or fossil fuels) will also be used to heat the air as it emerges from the tank. The newest compressed air engines also offer drivers the option of using fossil fuels or biofuels to heat the air as it enters the engine. Nonetheless, this technology represents a marked improvement over cars powered by internal combustion engines that produce significant amounts of pollution at any speed.

Air cars are also designed to be lighter than conventional cars. The aluminum construction of these vehicles will keep their weight under 2,000 pounds (907 kilograms), which is essential to making these vehicles fuel efficient and will help them go faster for longer periods of time.

Another advantage of air cars is that the fuel should be remarkably cheap, an important consideration in this era of volatile gas prices. Some estimates say that the cars will get the equivalent of 106 miles (171 kilometers) per gallon, although compressed air will probably not be sold by the gallon. A more meaningful estimate is that it may take as little as $2 worth of electricity to fill the compressed air tank, though you’ll also need gasoline to power the electric motor that compresses air while driving [source: Cornell].

The vehicles themselves also will be relatively cheap. Zero Pollution Motors, which plans to release the first air cars in the United States and estimates a sticker price of about $17,800, which would make these cars affordable to budget-conscious American buyers [source: Max].

Air Car Disadvantages

Clive Streeter/Getty Images
Could this happen to you in an air car crash?

While an air car produces no pollution running on already compressed air in its tank, pollution is nonetheless produced when the air is compressed, both while the car is moving and while it’s being refueled. As we mentioned earlier, the vehicle’s air compressor will probably run on gasoline, and this gas will produce pollution when burned.

The air compressor at the gas station will probably be powered byelectricity. The production of that electricity may or may not pollute, depending on how that electricity is generated. For example, coal-powered electricity could produce substantial amounts of pollution. Cleaner sources of electricity, such as nuclear power or hydropower, will result in far less pollution. According to the Web site Gas 2.0, an air car in the United States would create about .176 pounds of carbon dioxide emissions per mile based on the average mix of electric power sources during refueling. By comparison, a Toyota Prius Hybrid, which combines a battery-powered electric motor with an internal combustion engine, generates about 0.34 pounds of carbon dioxide per mile. So, while the air car is not quite pollution free, it still represents an improvement over one of the most popular hybrid cars on the market [source: Nuccitelli].

Distance could also become a disadvantage, depending on your travel habits. The distance that an air car can cover without refueling is crucial because very few filling stations will have compressed air pumps available at first. If you only plan to use your air car for short commutes — distances less than 100 miles –will be fine. However, the one-to-two hour wait for the car’s built-in air compressor to compress a tank full of air could become a problem on cross-country trips. Zero Pollution Motors — the American arm of MDI and the company likeliest to produce the first air car for the U.S. market — aims to have a car available soon able to travel between 800 and 1,000 miles on one tank of air plus 8 gallons of gas [source: Cornell]. Early prototypes, however, have traveled distances closer to 120 miles — good enough for your daily commute, but not quite adequate for longer trips [source: Motavalli].

What will happen if an air car suffers damage in an accident? After all, compressed air tanks can be dangerous. To reduce this danger, the air tanks are made of carbon fiber and are designed to crack, rather than shatter, in a crash. This crack would allow the “fuel” to escape harmlessly into the surrounding air. Manufacturers feared that air escaping from one end of the tank could produce a rocket-like effect and propel the car on a jet of air. The valve on the cars’ fuel tanks has been placed on the side to minimize this effect.

Despite these precautions, there is some concern that the air cars’ lightweight construction might make it difficult for them to pass stringent American safety requirements and that this could hold up the arrival of air cars in the U.S. marketplace. Other factors have come to the forefront as well, and we’ll learn about those next.

Air Cars in the Marketplace

Valery Hache/AFP
Although air car manufacturers have had problems bringing prototypes to the market, the AirPod One models shown here may soon be used in France for eco-friendly car rentals. 

India ‘s Tata Mo tors will likely p rodu­ce the first air car in the marketplace in the next few years. Tata Motors’ air car will also use the CAE engine. Although Tata announced in August 2008 that they aren’t quite ready to roll out their air cars for mass production, Zero Pollution Motors still plans to produce a similar vehicle in the United States. Known collectively as the FlowAIR, these cars will cost about $17,800. The company, based in New Paltz, N.Y., says that it will start taking reservations in mid-2009 for vehicle deliveries in 2010. The company plans to roll out 10,000 air cars in the first year of production [source:Max]. MDI also recently unveiled thejoystick-driven AirPod, the newest addition to its air car arsenal. Although the AirPod generates a top speed of only 43 mph, it’s also extremely light and generates zero emissions.

Major automobile makers are watching the air car market with interest. If the first models catch on with consumers, they’ll likely develop their own air car models. At present, a few smaller companies are planning to bring air cars to the market in the wake of the MDI-based vehicles. These include: 

• K’Airmobiles – French company K’Air Energy has built prototypes of an air-fueled bicycle and light road vehicle based on the K’air air compression engine [source: K'air]
• Air Car Factories SA – This Spanish company has an air car engine currently in development. The company’s owner is currently involved in a dispute with former employer MDI over the rights to the technology [source: MDI].

Initially, the MDI cars will be the only air vehicles on the market. However, MDI has reportedly licensed the technology to manufacturers in a dozen different countries, so air cars should be available around the world soon.

Consumer Guide^®‘s recommendations for getting better fuel economy may seem like no-brainers, but they really can make a difference. Our strategy is a three-prong approach: Alter your driving style, maintain your vehicle, and modify your driving mentality. Combine any of these tips, and you should start seeing an improvement right away.

Alter Your Driving Style

• S-L-O-W D-O-W-N. Going fast is so tempting. Not only do we do it to keep up with the flow of traffic, but if we can save even five minutes, it seems worth it. But if you’re on the highway, driving 60 miles per hour instead of 70 mph will save you 2-4 miles per gallon over the duration of your trip.

• Take it easy on the throttle. Don’t accelerate quickly or stomp on the brakes. Coast to a stop. You’ll save on fuel as well as wear and tear on your brakes, which will save you even more money.

• Shut down. If you’re waiting somewhere for a while, like at a train crossing for instance, turn off your engine. Even if it’s just for a minute, it can make a difference in your fuel economy, especially if you drive in the city a lot.

• Don’t warm up your vehicle for more than 30 seconds. This is a tough one, especially for us here at Consumer Guide^®, where Chicago’s frigid winters are a way of life. Thanks to technology, however, most modern fuel-injected cars only really need 30 seconds to warm, and hot air can start blasting into the cabin very shortly thereafter.

• Windows up. Again, this is tough, especially on pleasant days. But having the windows down creates aerodynamic drag that causes an engine to work harder. On the highway, this can decrease fuel economy by up to 10 percent.

Keeping your tires properly inflated will save you gas.

Maintain Your Vehicle

• Check your tire pressure. Making sure your vehicle’s tires are set to the recommended pressure can increase fuel economy by as much as 3.3 percent.

• Breathe easy. Next time you get your oil changed, have the air filter checked as well. Replacing a dirty air filter with a clean one can save up to 10 percent on fuel costs.

• Make sure your vehicle is in top running order. Read your owner’s manual and follow the manufacturer’s recommended maintenance schedule. If it’s time for a tune up, do it and you can realize up to a 4.1 percent increase in fuel economy.

• Buy the right gas. Your owner’s manual will list the correct octane gasoline you should use for your vehicle. Purchase whatever is recommended and no more. Premium-grade fuel is more costly and won’t improve economy in vehicles designed to run on regular.

• Lighten up. The less weight in your vehicle, the better your fuel economy. Clean out that trunk!

• Grease up. Using the manufacturer’s specified motor oil, and changing it per factory recommendations, can improve fuel economy as well. 

Keep your trunk empty. Carrying extra cargo around might be costing you at the pump.

Modify Your Driving Mentality

• Combine trips. Don’t run out two or three times a day. Hit all the stores you need to visit at once, and if possible, go to shopping malls where you can park and walk to several stores at the same time.

• Let someone else drive sometimes.

• Get some exercise. If you have the time and your destination is close, walk or ride a bike.

• Cool down. Gas up on cool mornings. Fuel is denser when cold. Gas pumps measure by volume, so if you pump when it’s cold, you get more gas for your buck.

The Biggest Savings

For most of you, altering your driving style and maintaining your vehicle might seem like enough to increase fuel economy. You’re likely to see perhaps a 10-15 percent improvement in fuel economy by doing those two things. However, you can save the most money by changing your driving mentality.

Consider this: If you get 16 mpg right now and you follow the steps outlined in “Altering Your Driving Style” and “Maintain Your Vehicle,” you’re likely to notice a 15 percent improvement in your fuel economy. That means you’ll average 17.6 mpg. Over a 12,000-mile year, that’s a cash savings of about $200.

By following the steps in “Modifying Your Driving Mentality” you could easily reduce the miles you drive each year by 1000. All else being equal, reducing the miles driven per year from 12,000 to 11,000 will save you $375. Combine the two, and you can reduce your annual fuel costs by $500 or more.