LUV Meeting July 2008

July 2, 2008 | etbe

At the last two meetings of LUV [1] I’ve given away old hardware. This month I gave away a bunch of old PCI and AGP video cards, a heap of PC power cables, and some magnets (which I received for free because they were in defective toys that could seriously injure or kill children). One new member was particularly happy that at the first meeting he attended he received some free hardware (I hope it works – most of that stuff hasn’t been tested for over a year and I expect that some would fail). Also there was another guy giving away hardware, so I might have started a trend of giving away unused hardware at meetings (he was giving away some new stuff in the original boxes, mostly USB and firewire cables).

For a long time (many years) at LUV meetings there have been free text books given away. One member reviews books and then gives them away after he has read them.

At the meeting Ralph Becket gave a presentation on the Mercury functional language. It was interesting to note that Mercury can give performance that is close to C (within 80%) on LZW compression (which is apparently used as a benchmark for comparing languages). Given the number of reasonably popular languages which don’t give nearly that level of performance I think that this is quite a good result.

After the meeting Richard Keech demonstrated his electric car. It’s a Hyundai Getz which has had the engine replaced by an electric motor but which still uses the manual gearbox. Richard did a bit of driving around with various LUV members as passengers to demonstrate what the car can do. Unfortunately I didn’t get a chance to be involved in that, so I’ll have to do so next time I meet him. One thing to note is that Richard’s car was not built that way by Hyundai, it was a custom conversion job. The down-side to this of course is that it would have cost significantly more than a vehicle with the same technology that was manufactured. One design trade-off is that Richard had batteries installed in the place for a spare tire. Last year the RACV magazine published a letter I wrote suggesting that small cars should be designed without a spare tire and that owners of such cars should rely on the RACV to support them if they get a flat tire [2], my option has not changed in the last year, I still think that cars which are driven in urban areas don’t really need spare tires so I don’t think that Richard is losing anything in this regard.

The motor driving Richard’s car runs on three-phase AC and a solid-state inverter is used to convert 185V DC to about the same voltage at three phase AC (I didn’t write notes so I’m running from memory). Apparently on long drives the inverter gets cooler rather than hotter – I had expected that there would be enough inefficiency in the process of converting DC to AC that it would get hot.

In a previous conversation Richard told me that he can drive his car 75Km on one charge and that it takes him 8 hours to charge when using an Australian mains (240V) plug rated at 10A. When designing such a vehicle it would be trivial to make it use a 20A plug for a 4 hour charge or even a two-phase plug for even shorter charging (I’m sure that Richard could have requested these options if he wanted them). But an 8 hour charge allows the vehicle to be completely charged during a working day and the use of the most common type of plug (the type used in every home and office) means that it can be charged almost anywhere (the standard mains circuit used in Australia is rated at 15A so special wiring is needed for a 20A socket). There is such a power point mounted on the outside of my house not too far from where a visitor could park their car. I anticipate that in a few years time it will not be uncommon for people who visit me to charge their car during their visit. Richard’s ratio of an hour of charge to almost 10Km of driving means that someone who visits for dinner could get enough charge into their car to allow for 30Km of driving before they leave. 30Km is about the driving distance to go from my house to a location on the other side of the city that is just outside the main urban area, so probably at least half of Melbourne’s population lives within a 30Km driving distance from my house. Not that I expect friends to arrive at my house with their car battery almost flat, but it does make it easier to plan a journey if you know that at point A you will be able to get enough charge to get you to point B.

I think it’s a good thing to have members of LUGs give things away to other people and to demonstrate technology that is of wide interest. I hope to see more of it.

Safety of Child Seats

June 26, 2008 | etbe

I have just watched an interesting lecture by Steven Levitt about car safety for children in the 2-6 age range [1]. The evidence he presents shows that the benefits for children in that age range are at best insignificant and that in some corner cases (EG rear impacts) the child seat may give a worse result than an adult seat belt!

He advocates a 5-point harness [2] for children in the 2-6 age range that is based on a standard adult seat and seems to be advocating a child “booster seat” integrated into the adult seat (which approximates the booster seats offered by some recent cars such as the VW Passat). He has a picture of a child in a child-sized 5-point harness to illustrate his point. But one thing that should be considered is the benefit of a 5 point harness for adults. Race car drivers use 5 point harnesses, I wonder how the probability of a race car dying during the course of their employment compares with the probability of an average adult dying while doing regular driving. I also wonder how a 5 point harness compares to a three point harness with a pre-tensioner, it seems quite possible that a 5 point harness would be cheaper and safer than the 3 point harness with pre-tensioner that is found in all the most expensive cars manufactured in the last few years.

He believes (based on tests with crash-test dummies) that part of the problem is that the child seat will move in an accident (it’s attached to a soft seat). It seems that one potential solution to this is to have child seats that firmly attach to some solid part of a vehicle. I had previously suggested that child seats which replace existing seats as an option from the manufacturer would be a good idea [3].

But there is a good option for making better child seats for existing vehicles. It is becoming common in the “people mover” market segment to design vehicles with removable seats. For example the Kia Carnival has three seats in the middle row which are removable and which attach to four steel bars in the floor. It should not be difficult to design a child seat which attaches to those bars and could therefore be plugged in to a Carnival in a matter of minutes. The Carnival is designed to have the mid row seats installed or removed easily and safely by someone who is untrained, while for comparison it is recommended that a regular child seat should only be installed by a trained professional (IE your regular mechanic can’t do it).

Car vs Public Transport to Save Money

June 25, 2008 | etbe

I’ve just been considering when it’s best to drive and when it’s best to take public transport to save money. My old car (1999 VW Passat) uses 12.8L/100km which at $1.65 per liter means 21.1 cents per km on fuel. A new set of tires costs $900 and assuming that they last 20,000km will cost 4.5 cents per km. A routine service every 10,000Km will cost about $300 so that’s another 3 cents per km. While it’s difficult to estimate the cost per kilometer of replacing parts that wear out, it seems reasonable to assume that over 100,000Km of driving at least $20,000 will be spent on parts and the labor required to install them, this adds another 20 cents per km.

The total then would be 48.6 cents per km. The tax deduction for my car is 70 cents per km of business use, so if my estimates are correct then the tax deductions exceed the marginal costs of running a vehicle (the costs of registration, insurance, and asset depreciation however make the car significantly more expensive than that – see my previous post about the costs of owning a small car for more details [1]). So for business use the marginal cost after tax deductions are counted is probably about 14 cents per km.

Now a 2 hour ride on Melbourne’s public transport costs $2.76 (if you buy a 10 trip ticket). For business use that’s probably the equivalent cost to 20Km of driving. The route I take when driving to the city center is about 8Km, that gets me to the nearest edge of the CBD (Central Business District) and doesn’t count the amount of driving needed to find a place to park. This means the absolute minimum distance I would drive when going to the CBD would be 16Km. The distance I would drive on a return trip to the furthest part of the CBD would be almost exactly 20km. So on a short visit to the central city area I might save money by using my car if it’s a business trip and I tax-deduct the distance driven. A daily ticket for the public transport is equivalent to two 2 hour tickets (if you have a 10 trip ticket then if you use it outside the two hour period it becomes a daily ticket and uses a second credit). If I could park my car for an out of pocket expense of less than $2.76 (while I can tax-deduct private parking it’s so horribly expensive that it would cost at least $5 after deductions are counted) then I could possibly save money by driving. There were some 4 hour public parking spots that cost $2.

So it seems that for a basic trip to the CBD it’s more expensive to use a car than to take a tram when car expenses are tax deductible. For personal use a 5.7km journey would cost as much as a 2 hour ticket for public transport and a 11.4km journey would cost as much as a daily ticket. The fact that public transport is the economical way to travel for such short distances is quite surprising. In the past I had thought of using a tram ticket as an immediate cost while considering a short car drive as costing almost nothing (probably because the expense comes days later for petrol and years later for servicing the car).

Also while there is a lot of media attention recently about petrol prices, it seems that for me at least petrol is still less than half the marginal cost of running a car. Cars are being advertised on the basis of how little fuel they use to save money, but cars that require less service might actually save more money. There are many cars that use less fuel than a VW Passat, and also many cars that are less expensive to repair. It seems that perhaps the imported turbo-Diesel cars which are becoming popular due to their fuel use may actually be more expensive than locally manufactured small cars which have cheap parts.

Update: Changed “Km” to “km” as suggested by Lars Wirzenius.

[1] http://etbe.coker.com.au/2008/06/16/cost-owning-car/

The Cost of Owning a Car

June 16, 2008 | etbe

There has been a lot of talk recently about the cost of petrol, Colin Charles is one of the few people to consider the issue of wages in this discussion [1]. Unfortunately almost no-one seems to consider the overall cost of running a vehicle.

While I can’t get the figures for Malaysia (I expect Colin will do that) I can get them for Australia. First I chose a car that’s cheap to buy, reasonably fuel efficient (small) and common (cheap parts from the wreckers) – the Toyota Corolla seemed like a good option.
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Perpetual Motion

June 11, 2008 | etbe

It seems that many blog posts related to fuel use (such as my post from yesterday about record oil prices [1]) are getting adverts about perpetual motion [2]. Note that the common usage of the term “Perpetual Motion” does not actually require something to move. A battery that gives out electricity forever would be regarded as fitting the description, as does any power source which doesn’t have an external source of energy.

The most common examples of this are claims about Oxyhydrogen [3], this is a mixture of hydrogen and oxygen in a 2:1 ratio. The wikipedia page is interesting, apparently oxyhydrogen is used for welding metals, glass, and plastics, and it was also used to heat lime to provide theatrical lighting (“lime light”). So a mixture of hydrogen and oxygen does have real-world uses.

The fraud comes in the issue of the claims about magnecules [4]. Magnecules are supposedly the reason for the “atomic” power of HHO gas (AKA Oxyhydrogen) which are repeated on many web sites. In brief, one mad so-called scientist (of course if he was a real scientist he would have experimental evidence to support his claims and such experiments would be repeatable) has invented entirely new areas of science, one of which involves magnetic bonds between atoms. He claims that such chemical species can be used to obtain free energy. The idea is that you start with water, end with water plus energy – then reuse the water in a closed system. Strangely the web sites promoting water fueled cars don’t seem to mention magnecules and just leave the “atomic energy” claim with no support – maybe magnecules are simply too crazy for them.

The water fuelled car wikpedia page is interesting – it lists five different ways that water can actually be used in a car engine (which are based on sound scientific principles and which have been tested) and compares them to the various water fueled car frauds [5].

I’m not accepting any more comments on my blog about perpetual motion solutions to the petrol crisis (they just take up valuable space and distract people who want to discuss science). I’ll allow some comments about such things on this post though.

Record Oil Prices

June 9, 2008 | etbe

MarketWatch reports that oil prices had the biggest daily gain on record, going up $11 in one day.

They claim that this is due to an impending Israeli attack on Iran and a weak US economy. $150 per barrel is the price that they predict for the 4th of July. That’s an interesting choice of date, I wonder whether they will be talking about “independence from Arabian oil”…

The New York Times has an interesting article on fuel prices [1]. Apparently sales of SUVs are dropping significantly.

The US senate is now debating a cap on carbon-dioxide production. The NY Times article suggests that if the new “carbon taxes” could be combined with tax cuts in other areas. If implemented correctly it would allow people who want to save money to reduce their overall tax payments by reducing fuel use. Also as increasing prices will decrease demand (thus decreasing the price at import time) it would to some degree mean transferring some revenue from the governments of the middle east to the US government.

The article also states that the Ford F series of “pickup trucks” was the most popular line of vehicles in the US for more than 20 years! But last month they were beaten by the Toyota Corolla and Camry and the Honda Civic and Accord. Now Ford needs to put more effort into their medium to large cars. With the hybrid Camry apparently already on sale in the US (their web site refuses to provide any information to me because I don’t have Flash installed so I can’t check) and rumored to be released soon in other countries Ford needs to put some significant amounts of effort into developing fuel efficient vehicles.

According to a story in the Herald Sun (published on the 23rd of April), survey results show that 1/3 of Victorians would cease using their car to get to work if the petrol price reached $1.75/L [2]. Now the Herald Sun has run a prediction (by the assistant treasurer and the NRMA) that $1.75/L will be reached next week (an increase of just over 10 cents a liter) [3].

The good news is that there will be less pollution in Australia in the near future (even if $1.75 is not reached I am certain that the price will increase enough to encourage some people to use public transport). The bad news is that our public transport is inadequate at the moment and there will be significant levels of overcrowding.

Car Sharing in Melbourne

April 13, 2008 | etbe

Recently I noticed that some parking spots in the city area are reserved for car sharing. There seems to be two car sharing companies operating.

Flexicar [1] costs $50 to join, has a $10 per month membership fee (which includes one hour of driving at a value of $12), and costs $12 per hour or $80 per day to drive a car plus $0.15 per Km if you drive more than 100Km in a day. They also have pre-paid plans which bring all the guesswork and complexity of mobile phone bills to car rental. Also they give discounts to members of the City Rewards [2] program which are greater than the membership cost, so anyone who plans to join them should join City Rewards first.

To use a car you phone up or use their web site to make a reservation. Then you find the car you reserved at it’s designated location and swipe your card across the windscreen to unlock the doors (presumably it’s an RFID card). The glovebox has the key for the ignition as well as fuel cards for any fuel you use a BP, Shell, and Caltex petrol stations (presumably if you run low on petrol when not near those ones you end up paying). All you pay is the rental rate and any tolls for toll roads you use.

When someone doesn’t return the vehicle to it’s designated spot on time there are penalty rates, which may include the cost of a taxi fare for the next person who had booked it.

It seems like a really good idea that can save significant amounts of money for people who live in the central areas (the costs of maintaining and insuring a car are significant, as is the depreciation on a new car as an asset).

The competitor is Charterdrive [3] which costs $25 to join (less than Flexicar but the same once you consider the discount), the same $10 per hour for 8:30AM to 5:30PM hours, and then cheaper rates for evenings and weekends. $25 for a night (5:30PM to 8:30AM the next morning) is good value if you want to drive home from work and then return the next day (if you work late then you might expect to pay $30 or more for a single taxi ride to get home). The weekend rate of $90 for 5:30 Friday to 8:30 Monday is also quite competitive, I expect that there are many people who only use a car on the weekend who could benefit a lot from this. $90 per weekend for 40 weekends a year (some weekends you would stay home or just use public transport) is $3600, insurance, registration, and basic maintenance of a car that you would want to own would cover most of that. Charterdrive does charge $0.20 per Km though for all journeys (with a discount rate of $0.15 per Km for long journeys on some plans), as opposed to Flexicar only charging $0.15 per Km for distances in excess of 100Km per day.

Charterdrive seems to be a newer company and has a far smaller presence. But it’s business model seems a little different and the focus on renting cars for people to drive home means that some people might benefit from being members of both companies. The $0.20 per Km makes Charterdrive more expensive more expensive for most city use, and the discounts offered for Flexicar seem to make it cheaper for use during business hours.

Charterdrive states that they have a deal with Red Spot Car Rentals [4]. It is not stated on their web site if you want to use one of their cars and they are all in use, I wonder whether a Red Spot car would be provided for the same price. Flexicar however claims that they aim to have a ratio of cars to members sufficient to make such things unlikely. Maybe it would be prudent to join both organisations so that if one had no vehicles available then you could use the other? In one city car park that I often pass the Flexicar and Charterdrive parking spots are adjacent so there would be no difference in convenience in terms of which one you use.

I wonder whether they will continue getting adjacent spots. If many people join both organisations then it would be more effective if they don’t get adjacent spots to get better aggregate coverage. I think that at the moment the main challenge for both companies is to grow the popularity of the car-sharing business. I expect that the real competition for who gets the biggest slice of that business will happen in a few years time.

Update:

There is another Australian car-share company in operation named GoGet [5], interestingly I discovered their existence when I reviewed the Google advertising on this post…

GoGet has a significant presence in Sydney, a small presence in Melbourne, and is only making a start in Queensland. Their hourly rates are significantly lower than the others (as little as $4.40 per hour) but distance rates are as high as $0.35 per Km. One significant benefit is that they have plans for two or three drivers which could allow an entire family to sign up on one account. If you drive less than 20Km in an hour (which would not be uncommon in city driving) then GoGet would be cheapest.

A Bio-fuel Petrol Station

April 12, 2008 | etbe

Today I happened to see a bio-fuel petrol station! I decided to check it out (even though I was traveling by tram in a part of town that I don’t normally visit so there was no possibility of any real purchase).

The station is Conservo [1]. Their main products are E10 petrol (10% Ethanol and 90% Petrol), B20 bio-Diesel (20% bio-Diesel and 80% Petroleum based fuel oil), and B100 (100% bio-Diesel). All the fuel that they sell has a biological based component. The prices for the fuel seemed a little lower than is charged by other petrol stations, but it’s difficult to tell as fuel prices can change rapidly.

I spoke to one customer who had just filled up his 4WD with bio-Diesel about his experiences. He said that he sometimes used B20 and sometimes B100. He had found no down-side to using such fuels but had noticed that when under hard acceleration the bio-Diesel fuel seemed to cause less dark smoke (IE less soot).

All the fuels that they sell are produced in Australia. There are issues with imported bio-fuels which are sometimes produced with slash and burn agriculture and often increase the prices for essential food items (such as corn in South America). As the fuel is produced in Australia such issues should not apply. According to a brochure they have facilities to allow people to deposit used vegetable oil which can then be converted to bio-Diesel.

Inside the store they sell a variety of organic foods and drinks, I bought a bottle of carbonated organic apple juice which was quite nice and at $3 was not outside the price range that I expect from a petrol station (which do tend to charge high rates for refreshments). It was not an unreasonably high price for an organic drink.

In the store they sell and promote a range of producthttp://en.wikipedia.org/wiki/Flash_points that are positive for the environment. They have a display about using algae to produce bio-Diesel fuel which has some interesting information but unfortunately didn’t list the productivity of algae fields in terms of the number of tons per hectare per year (or month or other time period).

One really interesting point I read on their web site concerns the flash point [2] of fuel. The flash-point is the temperature which allows enough of the flammable substance to evaporate to produce an ignitable mixture. Petrol is listed as less than -40C, fossil-Diesel fuel is greater than 62C according to Wikipedia (greater than 55C according to Conservo) while Conservo list the flash point of bio-Diesel as greater than 110C. Wikipedia lists the flash point of canola (rape seed) oil as 327C. This is described as being a benefit of bio-Diesel. While it’s obvious that this is a disadvantage for Petrol, I find it difficult to imagine a situation where a fuel tank could reach a temperature greater than 55C but less than 110C.

In their Good for the Environment [3] page they claim that the exhaust from burning bio-Diesel is less harmful to human health than that from burning fossil fuels. My previous post about Vegie Cars [4] is getting some comments suggesting otherwise. So far I haven’t found good references either way, but the discussion has raised some really good issues.

Update: Petrol’s flash-point is less than -40C not +40C.

Vegie Cars

April 11, 2008 | etbe

I’ve read a lot about running Diesel vehicles on plant oil, but one thing that was never clear was why some people claim that you need special chemical additives.

The article about converting vehicles to vegetable oil on the VegieCars.com [1] site explains all this. It seems that if you want to produce fuel which can be used in unmodified vehicles then you need to add a mixture of methanol caustic soda. This is going to be difficult, dangerous, have some expense, and probably not be that good for the environment.

The other option (which they recommend) is to modify the vehicle to accept straight vegetable oil. This means pre-heating the oil before it enters the engine (to lower it’s viscosity and make it vaporise more easily) and to filter the oil to remove solid objects and water.

A possibility is to have two separate fuel tanks so that you can switch between plant oil and petroleum based Diesel fuel. This is an option if driving in a cold climate (probably not an issue in Australia apart from a few mountains) and if you are concerned about the quality of your plant oil (a bad batch could clog the filters and force you to use petroleum based fuel).

They also have an interesting cost-comparison page to show you how much money you might save by using plant oil [2].

Their site is very interesting and has some good technical information, even if you never plan to drive a Diesel vehicle it’s worth reading if you are interested in cars.

A Better Design for Child Seats

December 22, 2007 | etbe

The current method of carrying young children (less than 4-6 years old) in cars is to have a special car seat fitted in the back seat. This has several significant problems:

It takes significant space in the back seat. The child seat is going to add at least 10cm to the length required in the back seat and often drives the purchase of larger cars (including SUV and 4WD vehicles that are known for being unsafe – especially for children). Having child passengers in a car is a great distraction for the driver, driving a large vehicle increases the difficulty in avoiding accidents – especially when parking.
The seat belts of the rear seats are used as part of the mechanism of attaching the child seat to the car. Seat belts are designed to stretch in a crash. It’s recommended that after a crash all seat belts that were used to secure people or objects be replaced as they will have stretched. Seat-belts that don’t stretch will cause more serious injuries. It seems likely to me that a seat belt used to tightly secure a child seat for a long period of time will stretch without a collision. Therefore if an older child is seated where they (or another child) used to have a child-seat then they may be at greater risk in the case of a collision.
Child seats should be fitted by specially trained experts if they are to be safe. The majority of seats are not correctly fitted and put children at needless risk (the cost of getting an expert to do the installation is small).

Some car companies are offering child “booster seats” that are an optional attachment to the rear seat (I first noticed this when reviewing the specs of the latest version of the car I drive – the VW Passat [1]). This is a good idea, but it doesn’t go far enough.

The best thing to do would be to provide a selection of back-seat assemblies as factory fitted options which have built-in baby and child seats. The combinations that would be most desired are:

Standard car back-seat for three adults (or two adults for a small car).
A regular seat (for an adult) at the road side of the car combined with a baby (backward facing) seat at the kerb side.
A regular seat (for an adult) at the road side with a young child (forward facing) seat at the kerb side.
A baby seat at the road side with a young child seat at the kerb side.
Two young child seats.

It would be quite possible to have all five of these options available from the factory. Of course there are corner cases that this doesn’t cover such as twins or parents who have two children so close together that they need two baby seats. For those cases option 2 combined with one of the current off-the-shelf baby seats would do. The number of different supported options would need to be kept reasonably small to reduce manufacture cost and to allow a reasonable market for second-hand seats.

One thing to note is that it’s recommended that the first forward-facing seat a child uses is smaller than the later one. Having options for three different built-in baby/child seats (rear-facing and two sizes of forward-facing) would significantly expand the number of combinations (and thus the expense). I suspect that the safety benefits of having an ideal method of securing a forward-facing child seat would compensate for the disadvantage of having it be too large for the child when they are first placed in it.

Another possibility would be to replace the rear seat with a more solid bench with bolt holes for baby and child seats. Securing a child or baby seat to a hard surface with bolts would be a much less technically demanding task than using a seat belt (and thus could be done correctly without expert assistance). Child and baby seats would have to be redesigned for this (I suspect that the safety of them relies on being attached to a soft surface), but after that I expect that safety would improve. For this option the rear seat could bold on to a hard surface that’s suitable for attaching child/baby seats so it would simply be a matter of removing the rear seat and installing the child/baby seat(s). The most common car design in Australia includes a 60/40 split rear seat (meaning that if you have a large item to store in the boot/trunk then you can fold down 40% or 60% of the back of the rear seat to allow the luggage to extend into the passenger compartment). This split could be extended to allow removing the base of the rear seat for 60% or 40% to bolt on child/baby seats.

Once a car model had been designed for replacing the rear seat there would be other options available. For example replacing the rear seat with luggage storage space. While almost all cars allow folding down the backs of the rear seats to store extra luggage the option of removing seats that you don’t need to give even more space is not common at all (I’ve only seen it advertised as a feature in vehicles with 6 or more seats).

I expect that if this idea was implemented it would allow a small car such as a Toyota Corolla to give an equal or greater amount of usable space for children in the rear as a larger vehicle such as a Toyota Camry. While better options for luggage storage would allow people who don’t have children to use a small car while still being able to carry the luggage that they desire. This would allow considerable savings on car purchase prices and fuel use. I expect that a reduction in fuel use world-wide could be achieved by removing the pressure on parents to buy large cars!

The poor support for child seats in cars is really surprising. One of the features that could be introduced is both top and bottom mounts for such seats. There is apparently a standard for this, some (not all) cars support it, but most baby seats apparently don’t. So baby and child seats are secured at the top (to a hook that’s bolted securely to the car frame and which was designed specifically for the purpose) and at the bottom to the seat-belt which was never designed for such things.

It’s a pity that some of the money spent on supposedly protecting children from drugs couldn’t be spent on making cars safer for them. The government is in the best position to force car manufacturers to improve their safety features while parents are in the best position to teach children about the dangers of drugs.

[1] http://www.volkswagen.com.au/pdf/Brochures/Passat_160807.pdf

etbe – Russell Coker

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Category Archives: Cars