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The reason why GM, Ford, and Stellantis have abandoned sedans in favor of SUV’s, CUV’s and trucks is that they are the most popular segments, and the sales of sedans and coupes has been falling for a while. The reasons seem to be primarily that trucks and SUV’s are trendy (no real logic to this trend) and that the public generally has little appreciation for the better driving characteristics of sedans and coupes over SUV’s and Trucks. Sedans and coupes handle better than big and heavy vehicles. The other reason is that the US automakers have not been competing very well with the foreign automakers (especially Toyota and Honda) in sedans and coupes. For GM, Ford and Stellantis, the SUV’s and trucks have been the most profitable vehicles.
Fuel economy is already mandated by law in most of the world. In the US is is called Corporate Average Fuel Economy (CAFE) and will probably get more stringent in the next few years. By limiting the average (weighted by sales) fuel economy of every car manufacturer, they preserve freedom of choice to the public, while still forcing better fuel economy. In other countries the law is written in terms of CO2 emissions, which are directly proportional to fuel consumption. You can convert directly from MPG to grams of CO2/mile.
Heavier vehicles (like SUV’s) do not tend to have more bearing issues than lighter cars because the engineers specify bigger and higher capacity bearings.
A lot of folks feel that OEM oil filters are the best quality, but the “premium” oil filters from puroator, Bisch, and Fram are actually usually better quality and filtering efficiency. OEM filters are certainly good-enough, but the specs on the premium filters are better.
For most of the other service items you might buy, major brand aftermarket is usually good quality. This includes brakes and suspension parts like ball-joints. I don’t tend to trust aftermarket gaskets though.
Hybrids cars have regenerative braking systems. When you first press on the brake pedal (up to a moderate level of braking force), you are actually not using the brakes at all, you are slowing the car down by forcing the electric motor in the hybrid system to provide braking force by acting as a generator that adds charge to the batteries. So you don’t need to coast, just try to brake early so you don’t have to use the friction part of the braking system. Most hybrids have a dash display feature to let you see when you reach the friction point. Whether the braking is done by regen or the actual brakes makes no difference to the wheel bearings. Wheel bearing life has nothing to do with the type of powertrain, just the design and quality of the bearings. the only things that increases the loads on the bearings are vehicle weight and how hard you brake or corner.
Of course heavier cars dissipate more heat into the environment, but that heat energy comes from the fuel that was burned to get the vehicle up to speed. We can just think of this of the effect of vehicle weight on fuel economy. Heavier cars generally use more fuel. Fuel economy (also measured as CO2 emissions) is already regulated throughout the world.
Dave
1) Electrical engineering is growing in importance because the trends towards hybrid and full-electric powertrains require a great depth of Electrical Engineering. Just look at the job openings at any OEM website and you will see a tremendous number of EE positions. The same holds true for computer science because every modern car has multiple computers running things. At a minimum, there is a powertrain ECU and a body ECU. Infotainment is another in many cars.
2) I am and have been an engineer. Started as a design and development engineer and finished as a technical specialist in R&D. I am still doing technical consulting.3) It is difficult to tell you how I used math in my profession. All I can really say is is that you need math, trig, and calculus as tools in engineering and science and computer programming.
Dave
1: This is a difficult question! I would guess that marketing is always going to be a major need in the automotive industry because it is and always will be very competitive. The other big need in the auto industry are the technical areas of electrical engineering and computer science.
2: The simple answer is no, you can’t build a runnable engine from scratch. All of the major components (block, head, crankshaft, rods, pistons) require very sophisticated engineering analysis to support design, and the materials and process requirements are very specific. Cranks and rods have to be forged or cast, blocks and heads have to be made from castings of very specific materials. Theoretically, you could make many of these components with 3-d printing (if you had good designs), but you would never get the strength of materials correct with 3-d printing.
3: Regarding the app: I have to assume this is an app that is meant to be used with an OBD2 reader, so there is no need to get the OEM involved. You also need to be sure there is no competition already on the market. I know there are battery condition apps already on the market for hybrid cars. As for implementing these function into electric vehicles, first check to see that these functions are not already available and in production. I think they are. Also realize that it is very difficult to get an audience with OEM engineering departments if you are not already a supplier. They are constantly bombarded with inquires from inventors, but you would start with the OEM website and look for the appropriate contact link.Best of luck with your studies!
Dave
I should probably add that any droplets of oil (even really tiny ones) that get into the combustion chamber are likely to cause preignition/knock at moderate to high loads.
question 1: the closest you can come to building an entire car engine from scratch is to build it from the basic components. You will need at least the following to be purchased: Finished block, Crankshaft, Pistons, rings, bearings, oil pan, cylinder head, all of the components of the valvetrain, and the entire camshaft drive system. The best way to get experience with all of this is to buy a used engine that needs a thorough rebuild. Completely disassemble and clean the engine (following the directions in the factory shop manual) and rebuild it following all the procedures and specs in the factory shop manual. Before you attempt all of this, yo umust obtain the factory shop manual and study the disassembly and rebuild procedures and decide if you have the skills, tools, and budget for this. Let me stress. The factory shop manual is essential and a great learning tool.
2. To become great at mathematics; good question! I don’t know any shortcuts. Find a good course and do all of the homework and stay ahead in the reading. Also, realize that mathematics is only the basis for the interesting stuff: Algebra, trigonometry and Calculus. Focus on what comes after mathematics.Best of luck to you!
Dave
Yes, this is correct of course. I wish more folks would review their owner’s manual for a schedule of all the required maintenance.
Dave
You do seem to have a lot of ideas for automotive design! The area you are talking about is the general category of car interior and exterior design. Every automotive OEM has big departments devoted to doing this. In order to work in this area I suggest you pursue and education in Design. You might start this by checking out the employment sections of the major auto companies web-sites and look for openings in interior or exterior design. Look at any listings and you will see the education requirements for these type of positions
A lot of folks don’t really understand what “calibrated for 87 Octane” really means. Of course it does mean that the engine can be expected to make its rated power and torque on that gas spec, but it doesn’t mean the engine will not be knock-limited in some normal driving conditions. For one thing, compression ratios are relatively high these days to optimize fuel economy in normal driving. The result of this is that the CR is a little bit too high to not be knock limited at full load. Every manufacturer does this, and they can do a god job because they all have knock detection systems to prevent knock damage and still allow the engine to run close to its knock limit at full load.
Also realize that high ambient temp, low humidity, high barometric pressure, and carbon deposits all hurt the actual knock resistance of an engine in the real world. The normal calibration process doesn’t set the spark advance to run on the knock limit (letting the knock detection system to stay active) under normal high-load conditions. Instead, the spark advance is calibrated to run really close to the knock limit but not to incipient knock. What all of this means regarding Octane is that you might expect using higher than specified Octane to offer a very slight performance and efficiency benefit when you are running at high loads, especially if you are running in hot/dry/ high Baro ambient conditions. Note that some ECU’s have adaptive calibrations that can infer what Octane you have put in your car and adjust the calibration map accordingly.
Interesting question! The basic answer is no, there is no difference in basic engineering quality within a brand line these days. The same technology and materials is used in Corolla as a Camry. The same materials are used in gaskets, seals, castings and stampings. A corolla engine will certainly last as long as even a Lexus engine. The only differences may be found in things like aluminum suspension pieces vs stamped steel in the cheaper car. There are anecdotally just as many Corollas driving around with 300,000 miles as Camry’s and Lexus; same for Honda Civics and Accords and Acuras.
Overall, most of the differences are things you can see, like the interior, performance, ride and handling, amount of sound deadening, etc. There is a lot less profit in entry level cars than upmarket.
