Are cars much more fuel efficient than they were in the past?
Cars have come a long way over the course of the years. Their efficiency has changed in many aspects, especially in fuel consumption. I am going to research the fuel efficiency changes in the Holden car brand. I will be investigating these changes in the Holden Commodore series of car types which have been made over the course of four “generations” of production, ranging from the first design - the Holden Commodore VB (1978-1980) – to the most modern design which is the Holden Commodore VE (2006-present).
I believe that almost all modern day cars are more fuel efficient than they were in the past. This is because modern day designs are lighter, more aerodynamic, have less friction with the tyres on the bearings and the ground, have more effective engine designs, more torque (which mainly helps with heavy loads on the car), and better transmission to consume less fuel. Car making companies have made many advances over the years trying to improve their cars, so it’s no surprise that modern day cars should be more fuel efficient.
The potential to improve fuel efficiency with advanced technologies is enormous. This is because only 17%-21% of energy from the fuel is used in the kinetic energy of moving the car. The graph below will show where all the energy created from the fuel goes. A large percent of it is from heat being released:

Here I have compiled a list of ways that you can improve a car’s engine fuel efficiency.
Increase displacement – Displacement in an engine is the amount of air displaced or sucked in by the movement of the cylinders. More displacement means more power because you have more gas to burn every time, therefore creating more energy. You can increase displacement by making the cylinders bigger or by adding more cylinders. Twelve cylinders are the limit or else it will start to have a negative effect. This will help a car’s fuel efficiency
Increase the amount of compression with each cylinder – The more strength you use to compress the air/gas mixture with each stroke the more power you will get out of the combustion.
Cool the air - Compressing air raises its temperature. This is bad though, because the hotter the air is during combustion, the less it will expand to produce more power. It is more fuel efficient to have cool air during combustion, and this is why some cars have an intercooler. An intercooler is a radiator which cools the compressed air before entering the cylinders.
Let air come in more easily – When the cylinder moves down to suck in more air, the air resistance can waste a lot of the engines energy. A way to prevent this is to add another valve for the air to go through or to have a bigger intake valve.
Make everything lighter –Having light-weight engine parts make it perform better and use up less energy. For example, each time a piston changes direction, the momentum force must be countered, wasting more energy. The lighter the cylinder, the less energy it needs.
Inject the fuel – Injecting the fuel helps to make the amount used in each combustion very exact and therefore not using any extra fuel. This improves the cars performance and fuel costs.
There is generally one of three different types of engines used in cars. They differ by the way that the cylinders and pistons are arranged. The three types are: inline, V, or flat Inline engine V engine Flat engine

Different types of engines have different advantages and disadvantages in terms of smoothness, manufacturing cost