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OP, look up car models available in both UK and USA to compare the engines available. Some examples include the Hyundai i30 to the Hyundai Elantra and Elantra GT, Ford Focus & Fiesta, Chevrolet Cruze to Vauxhall Astra, VW Golf. You’ll find their base gasoline engines are much smaller in the UK than in USA. If our government taxed owners based on size of engine and taxed fuel to the point of extremely high prices than we too would have such vehicles. You should also look at the vehicle weight of vehicles today compared to same models in the 80s. Besides growing in size they’ve also grown in weight from suspension and crash safety technology. Base model Golf and Civic of today have more HP than the GTI & Si of the 80s. Today’s non-turbo four cylinders have more HP than V6 cars of the 80s and the turbo 4s of today would beat factory spec V8s of the 80s while also offering much better fuel economy. You look at MPG numbers while some of us look at efficiency for power output. If consumers were willing to deal with 0-60 in over 10 seconds and quarter mile acceleration of over 20 seconds then we too would have high MPG numbers.
I agree with the 0-60 in over 10 seconds, via personal experience. All of what you are saying is true and I know the upswing in HP and torque numbers are correct. I expected more mileage to be the priority for engine developers after numerous oil crises. I also would have thought that the self aspirated diesel engines could have squeezed out 20 more percent HP and fuel economy over that 40 year development period. Now with the partnership between China and Toyota building the Hydrogen stuff they could turn the entire car industry inside out if they are successful.
I agree with the 0-60 in over 10 seconds, via personal experience. All of what you are saying is true and I know the upswing in HP and torque numbers are correct. I expected more mileage to be the priority for engine developers after numerous oil crises. I also would have thought that the self aspirated diesel engines could have squeezed out 20 more percent HP and fuel economy over that 40 year development period. Now with the partnership between China and Toyota building the Hydrogen stuff they could turn the entire car industry inside out if they are successful.
The priority of engine developers is to give the consumers a vehicle they want to buy while still meeting government emissions, average fuel economy, and crash safety standards.
I’m not an expert on the subject but interested as well. My understanding is that fuel injection took the place of carburetors in most car models during the 1980s and after that there really hasn’t been any significant innovation in the internal combustion engine beyond incremental refinements over the years. This would explain why fuel economy hasn’t improved much over that period of time except for hybrid engines.
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Exactly right. Law of Diminishing Returns. They took the $200 carburetor away and replaced it with a $2000 injector in order to gain 10% in fuel efficiency.
They only every-day-practical advantage of new, computer controlled engines over the old points & condenser ignition, flushing toilet carbureted cars of 60 yrs ago is that the new one are easier to start in cold weather. Only the super cars of that era could go 120mph. Now any run of the mill commuter car uses 4 valve, gear driven double OHC and over square pistons to achieve better power efficiency.
The vast majority of improved fuel efficiency achieved in the last 50 yrs has been because cars are now smaller and lighter. E = 1/2mv^2..... V has only increased a little. M has dropped a lot.
Remember the Geo? It got 50mpg, but the EPA and lawyers took it away from us. Now they're trying to shove EVs & self-driving cars up our a...er...down our throats.
Lots of good info here, but I'd like to add something:
The metric used to measure engine efficiency is "Base Specific Fuel Consumption", BSFC, which most typically has the units of grams per kilowatt hour - or in other words, mass of fuel vs how much usable energy comes from the crankshaft. Manufactures sometimes publish charts on these. For example:
Apart from performance, modern cars are much safer and more reliable. I dont have data for the latter, but the reduction in service garages and road side assistance organisations idicate much lower service cost. Our states road assist org is branching out into bicycle repairs as they are struggling with lack of need.
That would pass for a topographical map of the dead sea, if you had not explained the reference.
The chart actually demonstrates the sweet spot of Gearing and RPM, will producing optimum fuel economy being between 1800 and 2500 rpm from what I can see. Thanks for the chart.
The good news is things like front wheel drive and start/stop technology along with a host of other improvements mentioned in this thread have contributed to the improvement of the internal combustion engine over the time I am interested in..
Exactly right. Law of Diminishing Returns. They took the $200 carburetor away and replaced it with a $2000 injector in order to gain 10% in fuel efficiency.
They only every-day-practical advantage of new, computer controlled engines over the old points & condenser ignition, flushing toilet carbureted cars of 60 yrs ago is that the new one are easier to start in cold weather. Only the super cars of that era could go 120mph. Now any run of the mill commuter car uses 4 valve, gear driven double OHC and over square pistons to achieve better power efficiency.
The vast majority of improved fuel efficiency achieved in the last 50 yrs has been because cars are now smaller and lighter. E = 1/2mv^2..... V has only increased a little. M has dropped a lot.
Remember the Geo? It got 50mpg, but the EPA and lawyers took it away from us. Now they're trying to shove EVs & self-driving cars up our a...er...down our throats.
I drove carburated cars for many years before the advent of fuel injection finally made it's way to me and my cheap used car budget. There's a whole lot more to it than just mpg - in case you are maybe too young to understand how f'g terrible carburetors perform in every way compared to FI. Just for one difference, trying to start a carb'd car on a cold winter morning was often an adventure involving starter fluid, jumper cables and prayer.
You'll notice from the sample chart above shows the best efficiency at low RPM and high load. Basically since the advent of fuel injection, engines have had complete combustion across the rev range. It's possible to pull a little more heat energy out of the combustion chamber and turn it into useful motion by increasing the expansion ratio, but for the most part efficiency increases come from reducing parasitic losses. Friction goes up exponentially with RPM, and at higher loads the ratio of useful work to friction is better. At higher loads you also have lower vacuum losses, so having adequate gearing to keep the engine at the lowest RPM possible with the highest load is important. A CVT is the best possible gearbox for this, because anything with fixed gear ratios will necessarily swing outside of the optimal efficiency range.
Additionally, many technologies like variable lift and timing don't increase peak efficiency, but they broaden the area under the curve where you can get high efficiency.
I drove carburated cars for many years before the advent of fuel injection finally made it's way to me and my cheap used car budget. There's a whole lot more to it than just mpg - in case you are maybe too young to understand how f'g terrible carburetors perform in every way compared to FI. Just for one difference, trying to start a carb'd car on a cold winter morning was often an adventure involving starter fluid, jumper cables and prayer.
I'm so old, I remember when Michael Jackson was black. I covered the hard cold start problem in my post.
I also had to synchronize 12 Weber barrels and double, dual point distributors on 'Ferraris & Lamborghinis by ear. I'll stand by my original contention: new electronics haven't made that big a difference compared to their cost & complexity (not to mention unpredictability)....Pretty easy and cheap to remove a clogged carb jet and blow the dirt out. How long does it take to R&R a fuel injector? Can you do that on the side of the road?
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