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MM Write-Up: Modern Vehicle Drive-Trains
This write-up is not necessarily for those of you (which probably includes the vast majority of the forum) who keep up with the world of new vehicles and technology-advances in vehicle powertrains and energy-sources. But, for some new members, those who are confused by the ever-lengthening numbers of new tech-abbreviations, and those who find the world of vehicle powertrains somewhat less than totally interesting except when shopping for a new or replacement vehicle, well, this write-up may be just what you need. Read on.
Although some steam-powered vehicles (such as the Stanley Steamer) and battery/electric vehicles were significant in the early days of autos, the complexities and impracticalities of the steamers, and the strong range-limitations of the early electric vehicles, together with the growth of the oil industry, ensured that gas and diesel engines would predominate for decades. And that’s the way the industry basically remained until around the turn of the 21st century, when the first hybrids began to appear in both the American and Japanese markets…..although some gas engines could also run on other carbon-based fuels….which I’ll explain more later.
In the late 20th century, though, as concerns over gas/diesel engine emissions, fuel consumption, the economic power of OPEC (Organization of Petroleum Exporting Countries), the limits of world’s then-known oil-reserves, climate-change caused by carbon-emissions (of which I am partly, but not completely, convinced of myself), and, among other factors, the steadily increasing number of vehicles on the road, more and more attention began to be paid by the industry to the development of new and/or non-traditional fuels and powertrains for vehicles. I’ll go over them now, and try to explain most, if not all of them.
ICE (Internal Combustion Engines)
This refers to engines where the fuel (until recently, gasoline or diesel-fuel), is burned internally, inside the engine block and cylinders, or, in the case of Mazda Rotary engines, in the chamber created by the spinning rotor. it consists of a basic engine block with cylinders and pistons bored into it, around a crankshaft, in a straight line, V-pattern, horizontally-opposed "boxer" configuration, or, as with some fairly recent recent Volkswagen products, a “W” arrangement caused by two V-shapes. Most ICEs are four-stroke, with separate Intake/Compression/Power/Exhaust-stokes, although some old Saabs and other small European cars used the more archaic two-stroke engines, where oil had to be mixed with the gas (and added to the gas tank) to provide lubrication. In recent decades, especially in fleet-sales for Government agencies (my own agency had some) and some bus-lines for cities, ICE engines had the capability to either run entirely on carbon-based alternate-fuels such as propane and natural gas (which burn cleaner than gasoline) or to switch back and forth between traditional gasoline and these alternate fuels as needed. Gasoline-refueling-stations, of course, can be found almost any place…that is not the case for some of the alternate fuels, except perhaps at natural-gas utility companies. So, until recent decades, ICEs, particularly with gasoline and diesel fuel, were the industry-norm. Diesel-engines are generally similar to gas engines in operation except that, because of much higher compression in the cylinders (which fires the air/fuel mixture instead of a conventional spark plug), the engine-blocks and main components inside have to be much stronger and more durable. Some diesel engines, unlike gas engines, have removable cylinder-sleeves that can be replaced as they wear, with the basic engine block lasting almost indefinitely. Ethanol (alcohol) can be used in some ICEs…which is popular in racing because of the added safety of alcohol…it is less likely, in a crash, to catch fire the gasoline. But it is very inefficient as a power-source, having about 40% less energy per gallon than gas, which means poor fuel-mileage, requires large bulky fuel tanks, requires a lot of America’s corn crop to help produce it as an additive to some gasoline-blends, and, if it DOES catch fire, it It can be difficult to spot the fire because of the very light-blue, almost invisible flames.
HYBRIDS
The term “Hybrid” generally refers to a system with two separate engines or drivetrain-systems in the vehicle, usually a gas/electric hybrid, or, in some cases, a diesel/electric hybrid. In a SERIES Hybrid, the gas or diesel (ICE) engine will be linked to the electric motor in such way that the vehicle runs on the gas engine as the primary power-source, and the electric booster-motor cuts in as needed for extra power, or for use as a starter-motor again when the gas or diesel engine cuts off at idle to save fuel. The vehicle cannot run on either the ICE or electric motor separately, which limits its usefulness as a fuel-saver.
A PARALLEL Hybrid, on the other hand, is more sophisticated, flexible, and effective as a fuel-saver. Parallel hybrids allow operation on either the gas engine (which recharges the large hybrid battery-pack as needed), or, for comparatively short distances, on the electric motor alone, as long as the battery-pack is sufficiently charged. If extra power is needed, both the gas engine and electric motor can operate together, as in a Series hybrid. Hybrids used to be the main operators of the CVT (Continuously-Variable Transmission), which increases efficiency by eliminating regular stepped-gears in favor of a variable cone/drive-belt system, but, in recent years, more and more ICEs have been getting them because of their compactness, ease and low-cost of production, and simplicity, although durability is still a problem for many CVTs…their drive-belt systems have not yet, IMO, been completely perfected. All Parallel Hybrids, of course, have to have both a fuel tank for the gas engine and a large battery-pack for the electric motor, so that adds to the packaging-demands on space and sometimes lessens the amount of cargo room available. Some hybrids use one ICE and one electric motor….....others, particularly those from Toyota and Lexus, use an ICE under the hood and multiple electric motors, sometimes having one at each rear wheel, which also gives an All-Wheel-Drive effect for bad weather. Braking in Parallel-hybrids is often more effective than in traditional ICE vehicles, because the free-wheeling electric motor acts as a drag in braking, taking a load off the brakes, and also helps to recharge the battery-pack….it is known as Regenerative-braking.
EXTENDED-RANGE HYBRIDS
Extended-Range Hybrids, sometimes called Plug-in Hybrids, are more or less similar to Parallel Hybrids, except that, in addition, they have a plug/cord system that allows them to be plugged into regular household 110/120-volt outlets for recharging, or more powerful 220 or 400-volt rechargers. This recharges the battery-pack without having to burn fuel in the gas engine to do it, and can enable the vehicle to drive further on the electric engine alone as with a pure battery/electric system (which I’ll get to next). In fact, it will function as a pure-electric vehicle much of the time if one plugs it in regularly (hence the name “Plug-in-Hybrid”), don’t regularly drive it long distances at a time, and drive lightly-loaded, which makes fewer demands on the electric motor and battery. A small amount of gas-engine operation, though, even in the full-electric mode, may be needed (and programmed-in by the vehicle’s designers) just to keep the gas engine’s internal parts lubricated and its anti-freeze-coolant from deteriorating.
BEV (BATTERY-ELECTRIC-VEHICLE)
BEVs, essentially, are Extended-Range-Hybrids without the gas or diesel ICE…they rely totally on the electric motor, which means that they have a large, powerful, beefed-up electric motor and a large, high-capacity battery-pack. These electric motors can have prodigious torque, particularly at low engine speeds, and care and maturity is needed in their operation…..the Tesla Model 3 I sampled can easily outrun the fastest of the classic American Muscle-Cars I grew up with in the 1960s. Even with self-driving features, common sense says that you don’t operate one of these without paying close attention to what is in front of you….this is especially true for careless or inattentive drivers. As I write this, Tesla is the predominant maker of electric vehicles in the U.S., but other companies are rapidly catching up and/or providing competition….the new electric Ford F-150 Lightning truck, for example, is sure to be quite popular. BEV vehicles, in general, require less maintenance than vehicles (even hybrids) that use ICEs, because there are no fuel-systems, anti-freeze cooling systems, complex oil-systems, spark-plugs, or a number of other features that ICEs have, and need periodic maintenance for. Transmissions in BEVs also tend to be quite simple and/or maintenance-free…simply a one-speed power-transfer unit. But, because they lack an ICE to recharge the batteries, BEVs are significanly range-limited, particularly on long trips, although, once again, Tesla, in general, offers the most efficient batteries for range.
FUEL-CELL (HYDROGEN) FCV Vehicles.
Fuel-Cell vehicles are electric vehicles that, instead of having a large battery-pack, get their power from chemical reactions involving the use of compressed hydrogen….compressed to very high pressures of 10,000-20, PSI (pounds per square inch). The reaction in the fuel-cell produces electricity, which runs the electric motor. Right now, in the U.S., there are not very many of them on the market….perhaps the best-known of them are the Honda Clarity and Toyota Mirai, although the previous Honda Civic FCX was available for some time in California, which has a better network of hydrogen-refill stations than most other states. Personally, I like the idea of FCV vehicles, as they offer the benefits of electric power without the need for constant electric-charging-outlets, which many people who live in condos and apartments simply don’t have, or have access to. But, then, of course, outside of California, hydrogen-stations are not very easy to find, either.…it will take some investment in the infrastructure.
Like it or not, these alternate-fuel/propulsion vehicles are at least somewhat the wave of the future, and, in many nations and/or jurisdictions, more and more restrictions are being put on ICE vehicles, with some places eventually planning to outlaw them altogether and/or force them out of the market. Whether that actually happens or not depends (and will depend) an a number of political, cultural, economic, and scientific factors and issues that are beyond the scope of this write-up.
So, anyhow, for those of you that don’t follow the evolution of vehicle powertrains that closely, or are simply a little rusty on your sharpness or memory, I hope this helped.
MM
__________________
DRIVING IS BELIEVING
This write-up is not necessarily for those of you (which probably includes the vast majority of the forum) who keep up with the world of new vehicles and technology-advances in vehicle powertrains and energy-sources. But, for some new members, those who are confused by the ever-lengthening numbers of new tech-abbreviations, and those who find the world of vehicle powertrains somewhat less than totally interesting except when shopping for a new or replacement vehicle, well, this write-up may be just what you need. Read on.
Although some steam-powered vehicles (such as the Stanley Steamer) and battery/electric vehicles were significant in the early days of autos, the complexities and impracticalities of the steamers, and the strong range-limitations of the early electric vehicles, together with the growth of the oil industry, ensured that gas and diesel engines would predominate for decades. And that’s the way the industry basically remained until around the turn of the 21st century, when the first hybrids began to appear in both the American and Japanese markets…..although some gas engines could also run on other carbon-based fuels….which I’ll explain more later.
In the late 20th century, though, as concerns over gas/diesel engine emissions, fuel consumption, the economic power of OPEC (Organization of Petroleum Exporting Countries), the limits of world’s then-known oil-reserves, climate-change caused by carbon-emissions (of which I am partly, but not completely, convinced of myself), and, among other factors, the steadily increasing number of vehicles on the road, more and more attention began to be paid by the industry to the development of new and/or non-traditional fuels and powertrains for vehicles. I’ll go over them now, and try to explain most, if not all of them.
ICE (Internal Combustion Engines)
This refers to engines where the fuel (until recently, gasoline or diesel-fuel), is burned internally, inside the engine block and cylinders, or, in the case of Mazda Rotary engines, in the chamber created by the spinning rotor. it consists of a basic engine block with cylinders and pistons bored into it, around a crankshaft, in a straight line, V-pattern, horizontally-opposed "boxer" configuration, or, as with some fairly recent recent Volkswagen products, a “W” arrangement caused by two V-shapes. Most ICEs are four-stroke, with separate Intake/Compression/Power/Exhaust-stokes, although some old Saabs and other small European cars used the more archaic two-stroke engines, where oil had to be mixed with the gas (and added to the gas tank) to provide lubrication. In recent decades, especially in fleet-sales for Government agencies (my own agency had some) and some bus-lines for cities, ICE engines had the capability to either run entirely on carbon-based alternate-fuels such as propane and natural gas (which burn cleaner than gasoline) or to switch back and forth between traditional gasoline and these alternate fuels as needed. Gasoline-refueling-stations, of course, can be found almost any place…that is not the case for some of the alternate fuels, except perhaps at natural-gas utility companies. So, until recent decades, ICEs, particularly with gasoline and diesel fuel, were the industry-norm. Diesel-engines are generally similar to gas engines in operation except that, because of much higher compression in the cylinders (which fires the air/fuel mixture instead of a conventional spark plug), the engine-blocks and main components inside have to be much stronger and more durable. Some diesel engines, unlike gas engines, have removable cylinder-sleeves that can be replaced as they wear, with the basic engine block lasting almost indefinitely. Ethanol (alcohol) can be used in some ICEs…which is popular in racing because of the added safety of alcohol…it is less likely, in a crash, to catch fire the gasoline. But it is very inefficient as a power-source, having about 40% less energy per gallon than gas, which means poor fuel-mileage, requires large bulky fuel tanks, requires a lot of America’s corn crop to help produce it as an additive to some gasoline-blends, and, if it DOES catch fire, it It can be difficult to spot the fire because of the very light-blue, almost invisible flames.
HYBRIDS
The term “Hybrid” generally refers to a system with two separate engines or drivetrain-systems in the vehicle, usually a gas/electric hybrid, or, in some cases, a diesel/electric hybrid. In a SERIES Hybrid, the gas or diesel (ICE) engine will be linked to the electric motor in such way that the vehicle runs on the gas engine as the primary power-source, and the electric booster-motor cuts in as needed for extra power, or for use as a starter-motor again when the gas or diesel engine cuts off at idle to save fuel. The vehicle cannot run on either the ICE or electric motor separately, which limits its usefulness as a fuel-saver.
A PARALLEL Hybrid, on the other hand, is more sophisticated, flexible, and effective as a fuel-saver. Parallel hybrids allow operation on either the gas engine (which recharges the large hybrid battery-pack as needed), or, for comparatively short distances, on the electric motor alone, as long as the battery-pack is sufficiently charged. If extra power is needed, both the gas engine and electric motor can operate together, as in a Series hybrid. Hybrids used to be the main operators of the CVT (Continuously-Variable Transmission), which increases efficiency by eliminating regular stepped-gears in favor of a variable cone/drive-belt system, but, in recent years, more and more ICEs have been getting them because of their compactness, ease and low-cost of production, and simplicity, although durability is still a problem for many CVTs…their drive-belt systems have not yet, IMO, been completely perfected. All Parallel Hybrids, of course, have to have both a fuel tank for the gas engine and a large battery-pack for the electric motor, so that adds to the packaging-demands on space and sometimes lessens the amount of cargo room available. Some hybrids use one ICE and one electric motor….....others, particularly those from Toyota and Lexus, use an ICE under the hood and multiple electric motors, sometimes having one at each rear wheel, which also gives an All-Wheel-Drive effect for bad weather. Braking in Parallel-hybrids is often more effective than in traditional ICE vehicles, because the free-wheeling electric motor acts as a drag in braking, taking a load off the brakes, and also helps to recharge the battery-pack….it is known as Regenerative-braking.
EXTENDED-RANGE HYBRIDS
Extended-Range Hybrids, sometimes called Plug-in Hybrids, are more or less similar to Parallel Hybrids, except that, in addition, they have a plug/cord system that allows them to be plugged into regular household 110/120-volt outlets for recharging, or more powerful 220 or 400-volt rechargers. This recharges the battery-pack without having to burn fuel in the gas engine to do it, and can enable the vehicle to drive further on the electric engine alone as with a pure battery/electric system (which I’ll get to next). In fact, it will function as a pure-electric vehicle much of the time if one plugs it in regularly (hence the name “Plug-in-Hybrid”), don’t regularly drive it long distances at a time, and drive lightly-loaded, which makes fewer demands on the electric motor and battery. A small amount of gas-engine operation, though, even in the full-electric mode, may be needed (and programmed-in by the vehicle’s designers) just to keep the gas engine’s internal parts lubricated and its anti-freeze-coolant from deteriorating.
BEV (BATTERY-ELECTRIC-VEHICLE)
BEVs, essentially, are Extended-Range-Hybrids without the gas or diesel ICE…they rely totally on the electric motor, which means that they have a large, powerful, beefed-up electric motor and a large, high-capacity battery-pack. These electric motors can have prodigious torque, particularly at low engine speeds, and care and maturity is needed in their operation…..the Tesla Model 3 I sampled can easily outrun the fastest of the classic American Muscle-Cars I grew up with in the 1960s. Even with self-driving features, common sense says that you don’t operate one of these without paying close attention to what is in front of you….this is especially true for careless or inattentive drivers. As I write this, Tesla is the predominant maker of electric vehicles in the U.S., but other companies are rapidly catching up and/or providing competition….the new electric Ford F-150 Lightning truck, for example, is sure to be quite popular. BEV vehicles, in general, require less maintenance than vehicles (even hybrids) that use ICEs, because there are no fuel-systems, anti-freeze cooling systems, complex oil-systems, spark-plugs, or a number of other features that ICEs have, and need periodic maintenance for. Transmissions in BEVs also tend to be quite simple and/or maintenance-free…simply a one-speed power-transfer unit. But, because they lack an ICE to recharge the batteries, BEVs are significanly range-limited, particularly on long trips, although, once again, Tesla, in general, offers the most efficient batteries for range.
FUEL-CELL (HYDROGEN) FCV Vehicles.
Fuel-Cell vehicles are electric vehicles that, instead of having a large battery-pack, get their power from chemical reactions involving the use of compressed hydrogen….compressed to very high pressures of 10,000-20, PSI (pounds per square inch). The reaction in the fuel-cell produces electricity, which runs the electric motor. Right now, in the U.S., there are not very many of them on the market….perhaps the best-known of them are the Honda Clarity and Toyota Mirai, although the previous Honda Civic FCX was available for some time in California, which has a better network of hydrogen-refill stations than most other states. Personally, I like the idea of FCV vehicles, as they offer the benefits of electric power without the need for constant electric-charging-outlets, which many people who live in condos and apartments simply don’t have, or have access to. But, then, of course, outside of California, hydrogen-stations are not very easy to find, either.…it will take some investment in the infrastructure.
Like it or not, these alternate-fuel/propulsion vehicles are at least somewhat the wave of the future, and, in many nations and/or jurisdictions, more and more restrictions are being put on ICE vehicles, with some places eventually planning to outlaw them altogether and/or force them out of the market. Whether that actually happens or not depends (and will depend) an a number of political, cultural, economic, and scientific factors and issues that are beyond the scope of this write-up.
So, anyhow, for those of you that don’t follow the evolution of vehicle powertrains that closely, or are simply a little rusty on your sharpness or memory, I hope this helped.
MM
__________________
DRIVING IS BELIEVING
