Monday, December 03, 2018

A personal reflection: what would it take for me to place a bet on 2-strokes again?

A simple maintenance "that any Argentinian drunk of fernet con coca could perform" is often pointed out to be a clear advantage of spark-ignition engines, nowadays that newer Diesel engines are getting more complicated mostly due to emission regulations which are to a certain extent pointless. Then, one thing that may seem surprising is the absence of newer cars with 2-stroke engines, noticeable for having fewer moving parts than a 4-stroke due to the absence of a valvetrain. Even though classics such as a DKW 3=6 Sonderklasse may still be roaming around once in a while, it's clear they're not even nearly so close to mainstream anymore.
Sure the absence of valves, and having to rely on fixed-geometry porting for the intake and exhaust, may limit the useful RPM band of an engine, to the point it would either have some decent low-end torque and therefore serve right in a car at the expenses of high-revving ability or being too rev-happy while gutless slightly above idle. On the other hand, simply not even having to care about variable valve timing or any other increased complexity to the valvetrain is appealing for those who prefer an extreme ease of maintenance. Well, if in a car the narrower RPM band didn't really require a way to smooth out throttle response throughout a broader revving, in motorcycles this issue was addressed with a "power valve" on the exhaust in order to provide some sort of variable geometry to the ports. The most well-known of such is the YPVS fitted to Yamaha motorcycles such as the DT 200R, which was electronically-actuated in street-legal motorcycles fitted with Autolube and all-mechanical for racing models resorting to the power take-off which would otherwise serve to the oil pump, and then premix would be a must. While the dedicated Yamaha 2-strokes fanbase didn't bother premixing oil to the gasoline/petrol as much as the general public did, and some even retrofitted an all-mechanical YPVS to street-legal motorcycles.
Personally, considering the ocurrence of unproper handling of hazardous materials in Brazil, actually I don't consider it so awful to consume the oil alongside the fuel, instead of dealing with the risk of having waste motor oil to contaminate rivers and underground waters, plus some vegetable-based oils could be implemented even more easily to 2-strokes. Castor oil has been widely used as a motor oil in 2-stroke engines, even in racing applications, besides being pointed out to have a better solubility on ehtanol blends which are becoming mandatory on gasoline/petrol not only in Brazil. So, it may sound good also on the grounds of sustainability, offsetting the carbon and nitrogen footprint easier than a comparable 4-stroke.

2-strokes remain popular on marine applications, and the presence of electronically-controlled direct injection enhanced not only fuel-efficiency but also provided a more accurate emissions control. The only downside is the requirement of a separate oil tank, because the fuel won't go through the usual transfer flow alongside the intake air and the oil so the engine may be rendered inoperant in case of a failed oil pump, even though simply filling a tank would seem more appealing to the average Joe than calculating the amount of oil to make the premix anyway. Another point to consider is an ease to turn an engine fitted with direct injection into flexfuel, and Evinrude managed to make some engines able to operate even with heavy fuels such as aviation kerosene (JET-A/JET-A1/JP-8) and even Diesel fuel in case of emergency for military applications. Such level of suitability to a broader selection of fuels in a single engine may also become desirable for civilian applications, not just on outboard motors for inflatable boats but also for cars. Nowadays that vehicles such as the Volkswagen Tiguan now feature particulate filter even on gasoline/petrol powered versions due to some downsides of direct injection increasing the particulate matter emissions, it doesn't seem so out of question to address similar issues in a 2-stroke.
Well, despite the manufacturing cost of a 4-stroke being higher regardless of the presence of forced induction as it's standard for the Volkswagen Tiguan or in a naturally-aspirated similar, the simplicity of a 2-stroke may seem more attractive, considering the absence of a turbocharger which could turn into a maintenance nightmare. The recirculating-type lube system of a 4-stroke is essential for a turbo and prevents the fitment of such device to a 2-stroke of a similar displacement, even though both can achieve similar power figures. On the other hand, a much desirable feature of the new generation of turbocharged engines is the flatter torque curve, and this may prevent a reintroduction of 2-strokes on automobile applications to become successful.

Even though the dry-sump lube system may render 2-stroke engines safer for use on inclinations that would be easily found at off-road venues, which was a good sales argument for the DKW Munga and its Brazilian equivalent DKW-Vemag Candango on a head-to-head comparison to the Jeep Willys back in the day, the lack of interest from the Brazilian military forces for the Candango meant it had a shorter production run. Not to mention the possibility of upgrading some 4-stroke engines with a dry-sump lube system too, which could also avoid some irregularities to the oil flow while crossing steep terrains. Eventually this could become a niche market for 2-stroke engines in case Diesels get on short supply, but doesn't seem so likely to happen.

Even though 2-stroke engines had their days of glory in models, there was a period when the effort for developments became more concentrated on 4-strokes. It became hard to keep up-to-date with the 4-strole competitors, for which improvements such as variable valve timing and forced induction became mainstream. Models such as the DKW Junior became part of a glorious history which doesn't really seem to be making a comeback, despite having its merits. So, unless turbochargers and some emission controls as easy to work on as the ones fitted to a 4-stroke become widespread on 2-strokes, I wouldn't place a bet on them again...

Friday, November 23, 2018

Brasília and early Gol, different attempts to replace the Beetle with a similar mechanic

One of the Brazilian air-cooled Volkswagens I like the most is the Brasília, which was made from '73 to '82, with a 4-door body available from '76 on which was actually more popular for export but also had its fair share of the market either in public fleets or as a taxi. This orange one might eventually have been a taxi in my hometown Porto Alegre. Most were fitted with the 1.6L version of the good old boxer engine, while some rare ethanol-powered 1.3L ones were also available in the late years. It was also produced in Mexico, but as a two-door only which is quite surprising since it was supposed to be a more favorable market to the 4-door bodystyle. CKD assembly happened in countries such as the Philippines, Nigeria, Uruguay and Argentina, while CBU exports reached regional markets like Peru, Bolivia, Venezuela, Ecuador, Paraguay and Chile, and even in Portugal it had been available.

The same boxer engines also served the earlier versions of the Gol, such as this '80 model which still resorted to the 1.3L engine. Rumors quote this to have been an attempt from Volkswagen to get rid of a stock of engines which were refused by export markets. The replacement for the 1.6L engine on the following year increased the performance to levels deemed more acceptable by the overwhelming majority of Brazilian customers, and the "BX" lasted until '86 when subsequent versions of the Gol were by then all fitted with water-cooled engines. A key difference to the Brasília is the fact that the Gol had the engine mounted upfront and with front-wheel drive.

Saturday, November 17, 2018

Ancient bus with matching trailer in my hometown

Before articulated buses became mainstream in Brazil, there were some unusual approaches, such as this trailer meant to be pulled behind a regular bus on peak hours. Made by Marcopolo and matching the design of its Veneza series of city buses, these trailers had their frames supplied by the Randon company which is well known for its semi-trailers and other truck implements. These were common in cities near my hometown Porto Alegre, at the intercity routes connecting Canoas, Alvorada and Cachoeirinha with Porto Alegre.

Sunday, November 11, 2018

Brazilian Beetle with a rear wiper and possibly a water-cooled engine swap

Spotted this red Beetle last Friday night. It's a '76, and it was originally fitted with the 1300 air-cooled boxer engine. However, taking a look behind it, the engine lid had a bump that may suggest it to have been swapped with some water-cooled straight-4 such as Volkswagen's EA827, and so it would need clearance to fit the longer cylinder head which also sits taller. The slots on the lid itself and the ones between it and the rear window were shut, so it's uncertain how the air intake gets on its way to the carburettor. The radiator might have been mounted sideways between the engine and one of the rear wheels, which is not an unusual approach for Beetle-based vehicles converted to some water-cooled engine in Brazil.

However, the feature that has caught my attention more than any other was the rear wiper, which I was aware of some Beetles that had one adapted but never seen one personally before. Didn't really expect it to hang above the rear window instead of below, which is a more usual position for it on vehicles originally fitted with one. Apart from this Beetle, the only vehicle I can recall having the rear wiper hanging from above is the Range Rover Evoque.

Wednesday, November 07, 2018

'07 Honda CG 150 Job with a car-type receiver hitch

At a first glance, this Honda CG 150 Job may look like any other which still roams around Brazil, but it had been fitted with a rather unusual feature. It has been fitted with a car-type receiver hitch to tow a small trailer, requiring a supporting structure to be added to its chassis. I have been used to see similar setups for a while during my childhood, but haven't seen so many of those for the last 16 years due to the increasing popularity of cargo sidecars and the lack of a regulation for towing with motorcycles until some years ago. Nowadays the most usual receiver hitch setup for motorcycles is bolted to the rear suspension swing-arm. Spotted this one yesterday in my hometown Porto Alegre.

Tuesday, November 06, 2018

Are tricycles more prone to become a viable replacement for commercial vehicles than they would for private cars?

Tricycles are often treated as somewhat "inferior" to a conventional car, much like the motorcycles they might be based upon, and unfortunately the status plays a crucial role when it comes to private vehicle ownership. On the other hand, when it comes to commercial vehicles, the functionality and a low operating cost become more relevant to the point that some compromises become less relevant. So, even though there might be some fierce resistence to proposals of resorting to tricycles as a way to increase the pace of fleet renewal in 3rd-world countries, it would be pointless to exclude them at all from such process.
Resale value is still a matter of concern too, and sometimes even a passenger car such as a Fiat Uno or a commercial derivative might be prefered because of this factor alone, considering they're more of an off-the-shelf solution, and that would lead to an easier search for replacement parts when needed. Other than that, the fact that a more conventional vehicle is not so restricted when it comes to speed in comparison to some motorcycle-based trike with an engine considerably smaller also often sounds attractive in case the operator needs to perform some service in different places which would be more easily accessible through a highway.

Sure there will be a wider acceptance for private tricycles among certain users, not only recreational ones who frequently resorted to Volkswagen-based mechanicals, but it becomes somewhat specific. A segment of the market that could be served quite right with motorcycle-based models is represented by disabled drivers/riders who look out for private vehicle ownership more as a matter of necessity than luxury. Even though some amenities could be missing, there are users who put more value on an ease to find parking spots and maneuver on tight spaces, and then both a more affordable price and a lower fuel consumption compared to a car become a much valuable asset.

The increasing popularity of the use of commercial vehicles for private purposes, which may embrace even older ones such as an early Fiat Fiorino and also resembles to some extention the obsession for pick-up trucks in the United States, could also sound like a cultural barrier against the move toward tricycles as an effective replacement to ancient (and often not in their best shape) 4-wheeled vehicles in general. It may not prevent strictly commercial operators to be more open-minded for a shift in the middle of their struggle to retain or increase profitability. Another point to consider is the influence of China in some export markets, which may deem a Chinese tricycle with a fully-enclosed cabin and a flatbed as a good alternative to something else more complex.
Roadworthy certification and licensing requirements for motor vehicles may eventually turn into an obstacle too. The dual-airbag mandate for new 2WD vehicles (or single-range 4WD/AWD) with a payload lower than one metric ton in Brazil, enforced since 2014 when ABS brakes also became mandatory for every new car, LCV, truck and bus, rendered it nearly impossible to certify tricycles such as those electric ones imported by Hedesa (and their motorcycle-engined counterparts for those who wouldn't get rid of an internal-combustion engine so soon) with a car-like cockpit and side-by-side seating locally. Another approach that could be taken would be certifying such vehicles as agricultural machinery, which was the strategy used by the businessman Paulo Emílio Freire Lemos to circumvent safety requirements and allow the conditional registration of some Diesel-powered Chinese tricycles which he imported and sold as Gurgel TA-01. However, since in Brazil a commercial driver's license is required to operate tractors on public roads, it would become impossible for the average Joe to legally roam around in one of those...

In the end, no matter if it's as fancy as a Can-Am Spyder RT-S or as bare-bones as those Bajaj-made Indian derivatives of the Piaggio Ape, tricycles are most often considering too "specialized" to meet the versatility requirements of the entry-level car market. It becomes crucial to address the needs of a family that may afford to own only one vehicle, and this is where most of the options on the market still fail. So, despite eventually having some advantages that could be better explored on passenger transport duties, it's still more likely for tricycles to succeed on cargo duties.

Monday, October 15, 2018

What could be done for ethanol-capable "flexfuel" cars to become less mediocre?

It is undeniably quite challenging to make a "flexfuel" car retain some reasonable mileage figures on gasoline while it also features ethanol capability, especially when it's fitted with a random outdated engine such as the one which my mother's former Chevrolet Celta resorted to. Apart from an increase to the compression ratio and switching from throttle-body injection to sequential port-injection, that was roughly the same old Family 1-based introduced to Brazil in local variants of the Opel Corsa B which were rebadged as Chevrolet. Its ancient layout, praised for reliability and ease of maintenance, has some inherent drawbacks when it comes to overall efficiency.
Since 3-cylinder engines didn't have the same appeal in the Brazilian market as they do have now, the engine was basically a downgrade from the 1.2L to 1.0L because of lower taxes, and presumably also the economics of scale since it would still share some key design features with the 1.4L, instead of the 3-cyl 1.0L fitted to its European counterpart. The very same basic engine layout remains in use as the only powerplants available for the Onix, present-day entry-level Chevrolet in Brazil, in both 1.0L and 1.4L featuring flexfuel ability in the domestic market and also on regional export markets even though ethanol didn't really catch up as effectively anywhere else as it used to do in Brazil.
Maybe the competition with compressed natural gas in neighboring countries such as Argentina, Colombia and Bolivia has its effect on the seemingly lack of market opportunities for ethanol, plus the fact that it seems easier to compensate the inefficiencies inherent to the engine design on the fuel trim while resorting to CNG without side-effects while operating on gasoline, but an ancient engine layout also seems discouraging to take "flexfuel" capability so seriously. Despite being easy to work on this engine and even perform makeshift fixes, and most likely that's the reason why it wasn't phased out yet, there are some compromises that a handful of simple improvements can't effectively overcome.

It may sound kinda surprising, but GM has resorted to the bumped-up compression before it started to feature the "flexfuel" ability, at least to the 1.0L version, when local variants of the Opel Corsa C (guess what, rebadged as a Chevy once again) had it as a cheaper way to improve performance while the 4 valve-per-cylinder layout was prevalent among the competition. Since its fuel chambers were in fact kinda small, it seemed easier to overcome the risk of knock simply adjusting the ignition timing on demand. In the end, it led to a rough operation when the mandatory ethanol content on gasoline enforced in Brazil decreased due to sugar prices oscillations leading to a decrease in the ethanol offer for the domestic market. Corn-based ethanol, which could overcome this issue, is a taboo in Brazil...

Sure the initial interest on "flexfuel" capability in American vehicles such as the Chevrolet Lumina APV and the usage of methanol as an option mostly for the fleet market, for which the effects of the fuel availability limitations would've been somewhat more critic, has also led the intereset to a greater parts interchangeability with regular gasoline-only and pulled the plug on an eventual implementation of more advanced features in order to increase the efficiency while operating with alcohol fuels. Even though such conservative approach was not so pointless at all, there were possible ways to achieve similar goals without too much hassle to the maintenance, such as resorting to forced-induction as a way to emulate a variable compression ratio.
Sure a turbocharger could've been pointed out as a technical nightmare back in the day because of the thermal management which becomes somewhat more critical, plus there is a lot more pipes under the hood to limit access to other components, but the possibility of replacing the standard blow-off valve for an adjustable one to provide an over-boosting on demand. Maybe a belt-driven supercharger looks like a simpler option, since it wouldn't require too much mods to the exhaust system, but it requires some more mechanically-intensive mods to reach the same (or eventually superior) level of variation to the dynamic compression. No wonder it took a while for forced-induction to be taken really seriously on "flexfuel" vehicles...

At least in Brazil, the first "turboflex" available was the BMW 320i ActiveFlex, which also resorts to direct injection and therefore doesn't require any specific cold-start aid such as fuel pre-heating or the obsolete auxiliary gasoline tank which used to be available in dedicated-ethanol and earlier "flexfuel" cars in Brazil and decreases the risk of knocks even while resorting to a leaner air/fuel ratio on gasoline under some compression ratio which would otherwise remain more suitable to ethanol only. Turbo and direct injection became also available in smaller models too, such as the Volkswagen Virtus which features the 1.0L TSI 200 engine, alongside a naturally-aspirated 1.6L with port-injection more favorable by commercial operators such as taxi drivers simply because it's still easier to convert to CNG and the fear of turbochargers being prone to some catastrophic failure.

And even for those who fear the maintenance of a turbocharged engine or a direct-injection system, it could seem a good idea to give variable valve timing a chance. Fiat has fitted its Firefly engines with that technology, even though it's mostly aimed to improve performance in models such as the Mobi and the Argo, but it could eventually serve as another option to emulate a variable compression ratio.
Hadn't it been for the 1.0L limit for lower taxes, maybe that approach could be tried with the 1.3L version of that engine series in order to do so while retaining some acceptable performance on gasoline despite the decrease on volumetric efficiency while running a longer intake valve phasing overlapping the compression stroke, in a similar way to what Toyota did with the 8AR-FTS currently fitted to the Lexus IS and NX despite it not featuring "flexfuel" ability on them.

Sure the technical mediocrity has led to the lack of confidence on "flexfuel" vehicles as an approach to improve the marketing perspectives for ethanol, but the advances on engine design now available could overcome that issue. Countries such as Brazil where a higher tax bracket is enforced for bigger engines also have a political challenge in case the interest to take ethanol seriously becomes real, but the cards are on the desk. It's now basically a matter of which configuration to choose, but it's effectively possible to overcome the mediocrity and make "flexfuel" cars really desirable...