A few objections to the current emission standards for Diesel engines

For a long time, Diesel engines have been considered a good option due to their enhanced efficiency over spark-ignition (or older hot-bulb ignition) engines. Initially not so suitable for vehicles due to a poor power-to-weight ratio, further developments reduced this disadvantage in heavy-duty trucks, marine and agricultural machinery.

Since the 70's Diesel engines have been playing an important role in the automotive market, even leading some markets, mostly due to a demand for fuel savings after the oil crisys, but lately its adaptability to alternative fuels without performance changes or compromises to the efficiency while using heavier fuels such as straight vegetable oil in the days when biodiesel was still not taken so seriously.

In the medium-duty truck segment, the availability of spark-ignited engines became hard to justify, altough it still had some supporters in the American market for cultural reasons and easier cold-starts, and in Brazil due to the successful ethanol program. However, in the heavy-duty segments, Diesel prevailed, and it will hardly lose its leadership in a medium to long term...

Some old irons from that era, such as the early Volkswagen Passat (known in the U.S.A. as Dasher) and the Peugeot 504, are often deemed among the best options for experiences with SVO. The higher operation temperatures in the old-school indirect injection layout and the lower combustion speeds lead to a more complete combustion, reducing issues related to glycerin glazing inside the engines...

However, the same higher temperatures quoted as beneficial to an accurate combustion process are usually a reason to blame for the higher nitrogen oxides (NOx) emissions in Diesel engines, then it's quite predictable to see the direct injection as the predominant setup into newer vehicles such as the Peugeot 3008. There is also another opposition raising against the Diesel engines, with the increased popularity of gasoline-electric hybrids such as the Toyota Prius, raised on marketing to be perceived as a "cleaner" alternative in spite of the higher manufacturing footprint mostly due to the electric auxiliary driveline.

In spite of the combustion process in Diesels providing a higher thermal efficiency and adaptability to alternative fuels, including ethanol for direct injection engines, the current emission standards are often disconsidering these advantages, and actually decreasing it with the enforcement of some emission control devices such as the EGR (or the SCR as either an alternative or an add-on measure to reduce NOx emissions) and the DPF. Considering the increased fuel consumption from the usage of EGR and DPF, due to both the lowered combustion efficiency with the EGR recirculating exhaust gases inside the combustion chambers and the requirement of a small amount of Diesel fuel to the DPF "regeneration" (burning-off the trapped soot) process, the energy expense with more petroleum being refined and having its byproducts hauled to the refuelling stations, the tailpipe emisions reduction doesn't seem to match...

That tank between the fuel tank and the air filter is for the DEF

With the SCR/DEF/BlueTec system, which uses a solution composed of 67.5% distilled water with 32.5% industrial-grade urea, more prevalent in medium-duty and heavy-duty trucks and buses, another point to consider is related to the higher complexity to the logistic process due to another fluid required to the proper operation of the vehicle, which absence can lead to failure. No wonder military fleets have been granted an exemption from this kind of stuff.

Alternatives such as water injection at the intake, usually blended with some alcohol (either methanol or ethanol) up to 50% to avoid freezing, are easy to implement and effective in matter of NOx reduction due to the lower exhaust gas temperatures, and instead of just increasing the purchase cost of a new Diesel-powered vehicle or machinery it would be actually providing a pay-off due to the lower fuel consumption. Even pure ethanol can be sprayed at the intake for the same effect, reducing the volume required. Also, due to the enhancement of the combustion process, it decreases the amount of particulate matter and the fuel consumption, making more sense than wasting both the extra fuel required in an engine fitted with EGR or the urea used in the SCR, and keeping the intake manifold cleaner from oily residues brought from the crankcase by its closed vents. The energy input required for industrial processes to meet an increased demand for Diesel fuel and the urea fluid would become lower, and also due to the combustion enhancement some alternative fuels such as pure vegetable oil can be used in a safer way. The DPF is often also deemed to actually have a prejudicial effect regarding respiratory diseases, since the particulate matter oxidized into smaller particles can go deeper into the lungs. Ironically, water+methanol injection was already experienced by Rudolf Diesel himself, altough not being so widespread among OEMs.

Beyond its current relevance for the private vehicle market, Diesel engines also have been prevalent in emergency vehicles such as ambulances, and stationary appliances such as backup power gensets. While the efforts to reduce emissions can be considered relevant, the approaches for that matter have been quite unaccurate due to their side-effects, which not just decrease the efficiency but also raise the purchase cost due to the highly-sophisticated aftertreatment setups required for a compliant operation.

Why to get a swamp-cooler in a truck?

Swamp-coolers became a popular feature into trucks in Brazil since late 90s, due to the easy retrofitting even into older models such as a Fiat 210 (the earliest Brazilian version still featured the cabin of the Alfa Romeo Mille for a while).

The most popular manufacturers of these devices, namely Resfriar (based in Vacaria, exports regularly to Italy using the Resfrieuro brand, and to England labelled as TopCooling), Maxiclima (based in São Marcos, the city with the highest truck-to-inhabitant ratio in Brazil) and Climatizar (based in Vacaria), are located in Rio Grande do Sul state, which eases the logistics to export their products to Argentina and Uruguay, altough the Brazilian domestic market is still the most important.

Before...

As long as there is a roof hatch for the swamp-cooler to be assembled into, and some random spot to bolt an auxiliary water tank when it's not built-in to the evaporative module, as in this Brazilian Chevrolet D-20 (a local version of the C-20, with a Perkins 4-cylinder Diesel engine), there is virtually no deterrent to the installation.

After

Actually, even some vehicles that didn't have a roof hatch from the factory, such as the Kia Bongo and the Ford F-4000, Brazilian equivalent to the F-550, can be fitted with a swamp-cooler, as long as an opening is done in the roof. Well, it may sound dumb to have it into an F-550, since it got air-conditioner as a factory option, but considering the Brazilian market during the 90s it was still often deemed too expensive for many commercial operators, and there were also concerns related to increasements on fuel consumption and maintenance cost. Since there is no engine-driven compressor, a swamp-cooler doesn't increase the fuel consumption so significantly, and even tough it requires water to be added periodically, it's usually still less expensive than recharging a conventional air-conditioner with the synthetic gas it uses (either Freon/CFC or R134-a/HFC-134) and replacing components such as compressor clutches, belts, pulleys, and a few pipes and hoses. A swamp-cooler can also eventually weight less than a complete automotive air-conditioner setup.

In long-distance hauling, another vantage of the swamp-coolers is highlighted: since they don't require to be directly powered by the engine, operating only with electric power either from the battery or some random auxiliary source, the driver can sleep inside the cabin enjoying lower noise levels, while there is still some thermal comfort.

The only downside regarding swamp-coolers is the lower effectiveness when the natural air humidity is high. As opposite to a conventional air-conditioner, which takes moisture out of the air, a swamp-cooler hydrates the air due to the evaporative operational principle: hot air is aspirated in the evaporative module, goes thru a set of texturized filters soaked in water, which absorbs heat from the air and a little amount evaporates, therefore reducing the temperature.

Another aspect that makes a swamp-cooler too different from a conventional air-conditioner is that it actually works more effectively when there are less restrictions to the flow instead of keeping the same close air too long. It's usual to leave the windows rolled about 1-inch down when the swamp-cooler is on operation, altough with weathershields it might not be so easily visible from the outside.

Brazilian Army Toyota FJ-40 ambulance

Even special applications, such as ambulances can also get benefitted from the usage of a swamp-cooler. Activated-charcoal filters can also be applied, to reduce chemical and biological contamination into the medical compartment.

It's almost impossible to spot a cash-in-transit van from the Brazilian branch of The Brink's Company fitted with air-conditioner, such as this Mercedes-Benz Sprinter

It also became a prevalent feature even for cash-in-transit vans, at a point that vehicles fitted with this device outnumber the ones which have a conventional air-conditioner system. In this specific scenario, the benefits from the higher air renovation for the health of the operators is also notable, decreasing the fatigue, respiratory discomfort, skin diseases and blood pressure-related issues.

Disclaimer: the usage of any of the pictures from this article for any purpose, either commercial or educational, without authorization from the author is a copyright infringement. All rights reserved to Daniel Girald.

Swamp-cooler in a bay-window T2 Volkswagen station-wagon

It's not so hard to spot trucks with swamp-coolers in Brazil, since it's a cost-effective alternative to improve the thermal comfort inside the cabin even with the engine off, unless a regular air-conditioner which usually requires engine power to drive the compressor. There is actually no compressor in a swamp-cooler, neither a synthetic gas. Only water stored in a tank that can be mounted in virtually any compartment of the vehicle (or built-in to the swamp-cooler) and on-board electric power (there are 12V and 24V devices, the one to be fitted into a T2 might be the 12V) are required.

The air is aspirated thru an axial fan, pre-filtered to remove larger particles, dust and small insects, then goes thru a straw filter soaked with water and then the specific heat of the air induces a small amount of the water to vaporize, absorbing the heat and increasing the air relative humidity, all controled thru an electronic processor which adjusts the ventilation speed and the humidity increasement ratio. Altough it's often not the easiest position to ensure a perfect integration with the vehicle's original appearance, swamp-coolers are usually assembled at the top of the vehicle to allow a natural flow of the cooled air. The device used in this T2 is from the Resfriar brand, known in Italy as ResfriEuro and in England and Germany as TopCooling, with a tank mounted inside the vehicle instead of built-in to the evaporative unit.

Diesels: cleaner than hybrids

Hybrid cars, such as the Toyota Prius, have been praised by the "politically-correct" crowds due to a supposedly lower environmental footprint through an expectable operational life around 10 to 15 years, but it's quite unaccurate to trust only in marketing tricks. In the end, even an old beater can often feature a greater "environmental performance", eventually including 7700lbs. GVWR trucks such as the Mercedes-Benz MB-180 D which was assembled in Spain until '97, available in some markets with the legendary OM616 engine in a version rated at 79hp backed by a 5-speed manual front-driven transaxle.

Diesels have been known for their enhanced adaptability to alternative fuels, including waste cooking oils, while the most mainstream hybrids aren't so suitable to anything other than ethanol or gaseous fuels. An indirect-injection Diesel engine such as the OM616 can use nearly anything as fuel, altough some like ethanol and gaseous fuels might work only thru supplementary injection at the intake and still requiring a pilot-injection from either regular Diesel fuel or biodiesel, vegetable oil, or even old engine oil.

Dr. Rudolf Diesel himself was a visionary, predicting the possibilities to bring energy independence to agricultural villages in the former German Southeast Africa (currently Namibia), since biofuels could get their production less concentrated and more regionalized, allowing the choice for the most suitable one to regional needs or preferences, and cutting part of the cost of the logistic process to ensure its supplies. With direct injection, he even considered the possibilities to use pure ethanol, without any of the ignition improvers used in the Scania ethanol-powered buses from Stockholm. After all, the increased thermal efficiency in the Diesel cycle compared to a regular spark-ignited engine is still worth the higher initial cost, at a point that it took nearly all the market share in heavy-duty trucks.

It's also not so unusual for a Diesel engine to outlast a hybrid setup before an engine overhaul becomes required, even when the Diesel is submitted to higher load factors. The absence of an electric ignition system with many components prone to natural wear also decreases the amount of replacement parts and the respective raw materials and energy required to manufacture them.

Another increasingly controversial aspect regarding hybrids is about the higher mineral extraction and energy expenses involved in all the industrial and logistic procedures before the vehicle is ready to run. A set of battery packs can usually last 10 to 15 years before starting to fail, and altough its chemicals can be recycled, it's an energy-expensive procedure that also implies safety risks due to the reactivity of the electrolythic compounds. All the supposedly lower energy consumption during the operational lifespan of the hybrid vehicle is hardly recovered when compared to a Diesel-engined vehicle with similar performance ratings, even considering an eventually higher consumption increasement while using a specific alternative fuel as reference, such as E100 ethanol. For example, a Prius and a Peugeot Partner 1.4e-HDi can both get a 62MPG rating with gasoline and Diesel fuel respectively, while running on ethanol the Prius has a 30% mileage decreasement to 43.4MPG while the Peugeot can get a mileage decreasement around 50% to just 31MPG. Well, if we remember the lesser amount of DPF regen cycles in the Partner while using ethanol blends, an increasement lower than 50% on the fuel consumption might actually be expected when using pure ethanol due to the absence of particulate matter generation...

After all, a Diesel-powered old beater can still be way cleaner than a highly-acclaimed hybrid...

Brazilian mini hearses

In a country where full-size sedans are not the mainstream, and the station-wagons are getting pretty much neglected, funeral agencies in Brazil are currently using smaller hearses based on compact coupé-utilities very popular in the local automotive market.

Altough the short cargo tray, usually less than 6ft.-long, may not be deemed suitable to carry a casket, it's stretched from the rear overhang by means of a fiberglass insert totally integrated to the canopy used to enclose the compartment, ensuring the required dignity to the last trip. There's also a liner, integrated with the canopy and the rear extension too, providing an easy-to-clean surface without gaps.

The external layout of the vehicle ends up holding some resemblance to European hearses, which are often fitted with panoramic windows.

One of the most popular models to be converted into a hearse is the Chevrolet Montana, known in Mexico as Chevrolet Tornado and in South Africa as Chevrolet Utility. The engine is a flexfuel 1.4L 4-cylinder, backed by a front-driven 5-speed manual transmission.