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Smaller petrol engines should means that they have to carry more technology not just 1.3L to 1.2L. The just reduction in engine size does not mean any saving(about 1kmpl and even less in reality as the smaller engine has to work harder to push the car and so more emissions) in fuel but the life of the vehicle will come down leading to overall higher energy consumption. If this concept is to be believed the Bajaj Auto must have the best of the world fuel economy, despite its ultra light body.
There are a lot of technologies avaiable out there that can be used in these cars, one of the best methods of construction of petrol engines is cylinder deactivation. The mordern 4 cylinder 1.2/1.3L hatchback engines can stop injecting and firing two of the cylinders to save on fuel, when idling, fire only three cylinders with AC idling and light acceleration. This will mean that each cylinder still operates on 14:1 mixture ration(low emissions). The cheapest thing that i feel is that cars can have as of now is selective firing, i.e Instead of engine firing all the cylinders all the time, they can fire three cylinders in a cycle and the other two in the next cycle(some what like deactivation but with low cost and higher benefit). This will directly produce a 10-15% increase in fuel economy in cities like Bangalore where the engies idle most of the time. Will not help much in other cities.
Valve train technologies are quite mature and are quite cheap to bring in. So it is quite easily possible to bring in hardware like VVTi at allmost no increase in price. These increases fuel economy by about 5%, by providing a small boost for torque at low end and can be coupled with reduction in cylinder size be small invisible numbers to provide real economy increase. The VTech is better technology as it provides real low end torque boost with lower lift and three vavle setup at low RPM and high lift and four valve setup at high RPM.
One more interesting concept that can be brought in is mixed cylinder size. All the cylinders should not be of same size. within the cylinders there should be a variance of upto 50%. That is if the engine is 700cc and twin cylinder, one cylinder can be about 400cc and other 300cc. This combined with selective firing can allow a verity of cylinder size combinations from 300cc to about 700cc in very small steps if we include the partial firing. Allowing you to have good high end as well as good mileage. The cost of this change is barely in the production shops(but you also need multiple piston heads which makes it a bit pricey on the manufacturing front) and will provide you with about 10% savings.
Dual fuel in all cars, there is always the simple way where you add kit capacity that allow your car to run on petrol as well as CNG/LPG according to your area(many cities dont have LPG and other no CNG). One more complex way i think will help is injecting fuel and LPG/CNG together into the cylinder, this will reduce the amount of CNG consumption and Petrol consumption by producing even flame spread and lean but well formed mixture. This is something i guess is never tried out, so will need some research but i guess the current business model may not allow this to happen. This mixture ratio can be varied as RPM changes, to provide the best technology avaiable.
Equally good concept is turbocharging, we can go for engine about 60-70% the size of the current one and introduce a high spool/bypass turbo(not the ones that come active at high speeds). That is our cars like i10 can have about 800cc engines with high spool turbo and higher lift cam setup. This will produce quite a good savings as people will get serious amount of torque at low speed, allowing taller gears than that of 1.2L engine. The Fiat T-Jet engine found in Linea(1.3L) is a good example, this concept has just started and will become famous world wide(dont tallk about manufacturers in India). The next panda will come with a 900cc engine, if you want a peek. This i think will be biggest step in increasing fuel economy at lowest cost. you can get upto 3 kmpl with our firms just spending about 20-40K on a F.G. bypass Turbo. Prices will further come down as numbers increase. It can come as low as 10-15K
The cylinder deactivation setup will work best if we have some form of allowing the engine to breathe free. We will need two modifications on the existing engines, two/four computer controlled butterfly valves(By-Wire) and a air transporter tube near the intake manifold to carry air into the exhaust port(activated by solinoid). These to will allow the cylinders to operate with minimal pumping losses when deactivated and thus very much delaying the activation time and some more fuel.
Better way of boosting that power further is to use a parallel Hybrid setup with CVT/Manual transmission. When the engine is driving at low RPMs the motor can step in and produce a few BHPs more to produce the necessary torque.
In all these setup the petrol engine needs to operate like diesels, the ecm must think about the torque necessary to keep the engine working. All these changes are i guess presented in increasing order of cost and research.
Diesel engine in itself has lesser scope for improvement compared to petrol if you take into consideration what is present in the Swift. The major technological improvment is already over and what ever happens it will be tweaking and tuning. So getting a better ECM will increase economy and power.
The next biggest change the diesel can have is a piezo injector may be making upto 10(not sure) injections per cycle allowing some more torque production and economy. The mordern Merc diesels have it.
You can always go in for cylinder deactivation and hybrids but already higher price of diesel engines means that technology is going to flow in a lot slower. The petrol cousins will easily outshine diesels(in overall cost and comfort) with some of the technologies i posted before but the fact that amazing diesels are already available means that we can save immedietly by buying diesel instead of petrol but over a lifetime petrol cars are still far cheaper.
But the double edged sword is buying diesels is that if we buy diesel car we become heavy on the economy(country). That is government has to think four times to increase the price of diesel(Inflation) which affects our infrastructure investments(also directly by lower taxes collected on every litre diesel). There is a also a steady increase in consumption of diesel world wide and we will hit a time when diesel will be far pricier than petrol in the market(it already is pricier) though our government will sell us at cheaper price. This means there will be pressure built in some time to quickly increase the price of diesel or our economy has to bear the price by paying through other tax. The tax that we are already paying and invisible is serious increase in transportation cost of goods and we pay a lot more on all products. If we still primarily drove petrol cars, our cars would cost about 50K-1L less(lower input costs) and petrol price would be around the same arena(Rs.53-55). This advantages may be directly visible in the US economy, but theirs is far mature than ours. Also, Hydrogen will move in more easily if we run more on petrol than on diesel.
All these disadvantages plus considering the fact that higher maintainance and purchase price of diesels means that petrol makes a good choice for personal offerings. So think thrice or even 10 times before buying your next diesel car(dont ask why should i pay for more when cheaper fuel is avaiable), but considering the trend we will continue paying the price as smaller and better diesel car will keep comming in.
Last edited by tsk1979 : 2nd June 2008 at 11:31.
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31st May 2008, 13:51
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