Introduction: What is a hybrid car?
The term hybrid in general use means either:
- The offspring of two different species
- Something having two kinds of components that produce the same or similar results
So a hybrid vehicle is either a cross between an ICE vehicle and electric vehicle, or a vehicle having two kinds of things that produce similar results, which in this case is having two types of motor: an electric motor and an internal combustion motor.
Combining gasoline and electric to power a car goes back to 1900, even earlier for trains and ships. One I started looking hybrids have been around way longer than I expected and in far more uses than I expected. Technically, even what we call ‘non-hybrid cars’ have both types of electric motors.
Types of cars combining both electric and internal combustion engines.
Although the first hybrids appeared back in 1900, you could call technically call almost every car with an internal combustion engine a ‘hybrid’, we current have the following names:
- non-hybrid internal combustion engine:
- the electric motors are only used to start the vehicle and charge the battery, even if they are capable, they are intended to to be used for propulsion of the vehicle.
- mild hybrid: all energy is derived from fossil fuels
- almost identical to the ‘non-hybrid’ but with slightly upgraded batteries and motors.
- electric motors are charge the battery from: a) regeneration or b) rotation of the ICE
- electric motor(s) boost power from the ICE, but do not propel the vehicle on their own.
- hybrid (or “self charging” hybrid): still all energy is derived from fossil fuels
- again similar to the mild hybrid, but with even further upgraded batteries and motors
- as with the mild hybrid, battery charging from either a) regeneration or b) rotation of the ICE
- unlike the mild hybrid, the battery is large enough to enable the motor to be configured to drive the vehicle on electric power alone, although typically only less than 5 km (3 miles)
- plug-in hybrid: energy from a mix of fossil fuels and the electric grid
- the main charge is revealed by the name, this is a hybrid that add the capability to of charging by bring plugged in.
- despite marketing on some hybrids suggesting plug-in capability may result in slow recharging, plug in cars can be used as a conventional hybrid any time plugging-in would be inconvenient.
- some cars are just like conventional Prius style “self charging” hybrids in that they also “self charge”, with an added ability to charge from a plug, but most have even larger batteries to allow a longer range on electric power, up to 200km (120 miles) in ne or two cases, to take advantage of the larger battery.
All hybrids, replace both alternator and starter motor with a single electric motor connected to the main drive system which perform both roles of generator and starter motor.
This system is more efficient, because instead of a combustion engine providing the power to generate electricity, an electric motor generates electricity from regenerative braking, which means energy that would otherwise be lost is recovered as electrical energy.
This reduces complexity of the starter motor, solenoid to engage the starter motor, and the alternator and drive belts to drive the alternator.
Internal Combustion Engines
there are two key points:
- Inefficient at all times, and efficiency varies depending on conditions.
- Internal combustion fuels are 20x more energy dense than current batteries.
Inefficient at all times, and efficiency varies depending on conditions.
An internal combustion engine first turns chemical energy into heat, and the converts heat into motion. As it clear from how much heat is generated, only a fraction of the heat is successfully converted into motion. So much remains as heat, that a quite complex cooling system is needed, which also consumes energy. The result is efficiency peaking around 30%, and dropping whenever RPM are not ideal for the load on the engine at the moment, resulting in the need for an ever increasing number of gear ratios in the quest to keep RPM at the number for optimum efficiency.
The result is that while efficiency is never great, it is at its best when travelling at constant speed, which stopping and starting, accelerating and decelerating, all significantly decreasing efficiency.
The result is vehicles with ‘urban’ cycle efficiency even lower than highway efficiency, despite the lower average speeds.
Internal combustion fuels are 20x more energy dense than current batteries.
A relatively small and light gasoline or diesel fuel tank holds far more energy than any similar size battery so far. Lots of energy, means lots of range. Despite the inefficiency, range is the advantage.
A car with a 70 litre (18.5 US gallon) tank holds around 618 kWh of energy. Fitting a 618 kWh battery to a car is way beyond what is practical with batteries today. That same 70 litre fuel tank, takes less space and weight than the best 20kWh battery in 2022. The energy density data is here, but no battery has reached 1/20th of the energy density of gasoline or diesel.
If you want even more stored energy, it is relatively low cost to increase the fuel tank size, or add an extra tank. Accessory long range fuel tanks are available for some vehicles, either as aftermarket or in some cases from the original brand, and some aftermarket companies will fit custom long range fuel tanks. Fitting a 60 gallon (227 litre) fuel tank would provide over 2,000kwh of energy.
With all this ability to store energy, the possible range of the internal combustion engine vehicles is unrivalled, although in practical use, a range of a around 500-620 miles (800-1,000 km) has be found to all almost anyone needs.
Electric Motors, Generators and Alternators.
An electric motor is a generator, and vice versa.
A generator is also a motor, an alternator is also a motor, and motor is also a generator. While all motors can be used as generators or vice versa, design can be optimised for acting as 1) motor, 2) generator 3) both.
As an alternator is simply a specific type of generator, having linked to an article on how the alternator class of generators can still also function as a motor, consider the word generator to mean ‘generator or alternator’ from here.
There are many articles about the differences between generators and motors, but the differences all come down to how optimise the same basic design for each of these two roles. The core of an electric motor or generator is:
- Forcing the armature to rotate, generates an electric current that can be used to charge a battery.
- Providing an electric current to the brushes, will generate rotational force on to the armature.
Any motor or generator is a device that can perform both roles, the only difference is how well optimised the device is for each role.
Efficiency and power from zero to maximum rpm.
Electric motors are are over 3x more efficient than internal combustion engines, because far less energy is lost as heat. This efficiency is generally maintained through the range of motor speeds. Unlike the combustion engine, even from stationary, simply apply voltage, and maximum torque is available.
This is why there are electric starter motors, and they do no need their own starter motor.
The constant efficiency also means there is almost zero penalty from changing speeds, which means almost all electric cars have only a single speed ‘gear box’, and is one reason EVs use less energy at lower speeds as typical of the urban cycle, despite the stop and go requirements.
Use electric motors to complement ICE.
The full torque from zero RPM can solve the problem of zero (or even negative) power at zero RPM from an ICE, which is why almost all ICE vehicles also have electric ‘starter motors’.
Beyond starting the motor, where electric motors have the most to contribute is in ‘urban cycle’ motoring, and accelerating from ‘idle’, without needing to first spin up to a powerband.
‘Regen’ – or regenerative braking.
All modern vehicles with an electric motor, EV, hybrid, plugin hybrid, range extenders included, harvest energy that would otherwise be lost under braking. Some of the energy the vehicle produces to accelerate the car, needs to be “absorbed” during deceleration. Conventional brakes convert this energy to heat, which produces wear and is not desirable. Vehicles with an electric motor use the motor as generator during deceleration, capturing that energy as electricity instead of heat. This is known as “regenerative braking” and provides two benefits:
- Less heat and wear during deceleration.
- Recovered energy can be used to reduce fuel consumption.
An introduction by video/podcast.
The following you tube video provides as reasonable summary without all the details or the need to read, and could even be listened to without video.
Hybrid history: evolving combinations of combustion & electric.
(this section has updates in progress)
There have been hybrids since 1900.
I was surprised by what a bit of research uncovered. In 1900 Henri Pieper produced a serial hybrid, and just one year later, Ferdinand Porsche added an gasoline motor to the Lohner–Porsche:
Several Austrian land speed records were set, with a top speed eventually achieving 37 mph (60 km/h) with Porsche at the wheel. It was victorious in a number of motorsport events including the Exelberg-Rally in 1901.Wikipedia: Lohner–Porsche
Back at the start of combustion engine vehicles, there almost as many hybrids as non-hybrids. It is important to remember, there were more electric cars than gasoline cars until around the Model T reached its peak, and many early hybrids were created to extend the range of an electric vehicle, by tapping into the stored energy density of gasoline, more like the BMW i3, than the Toyota Prius.
Tillings-Stevens produced ‘serial hybrids’ from 1906-1950, but these were commercial vehicles. For trains, serial hybrids have long dominated, and for large boats serial hybrids have long had a role, with almost all submarine hybrids, but with consumer cars, hybrids continued, but did not again enter the limelight until the Toyota Prius.
From 1920, for the mainstream hybridisation becomes only starter motor.
Cadillac in 1912.
You could say all modern internal combustion engine (ICE) vehicles are ‘hybrids’ that combine ICE with an at least one electric motor, ever since Model T Ford added an electric starter motor, back in 1919. Electric start was first introduced with the 1912 Cadillac Model 30, and as the Model T and other cars adopted it, the electric starter became a necessary inclusion in any internal combustion vehicle.
Quite soon a standard design emerged, where there were was also an electric motor included with every internal combustion engine. The only thing that varies now, is what are the roles of each engine/motor in the partnership.
From the 1920s, internal combustion engine (ICE) vehicles have had an electrical system, with the combustion engine powering not just the car, but a generator, or more specifically an ‘alternator’, which is an efficient type of generator, which charges a battery that powers an electrical system.
For most of 20th century, the electric motor was only used to start the internal combustion engine, despite there always having been potential for a greater role.
The History Of Hybrid vs Starter Motor Only.
When the Model T Ford was introduced in 1908, internal combustion engine vehicles delivered on the had compelling potential of low cost, high energy density gasoline. Although the complexity of the engine, the messy fuelling the difficulty starting meant it was not the most common engine type at the time, the energy density of gasoline meant it had the most promise. At the time, the electric grid infrastructure was not yet in place and even nickel based batteries were not ready for mass production, battery swapping of lead acid batteries would have been problematic and “gas stations” were easier to make into a business than recharging stations.
In simple terms, while electric cars could be “city cars”, the internal combustion engine car could also be road trip capable. Gasoline was low cost and abundant, and that lack of need for stop start diving meant that if you energy was coming from gasoline anyway, and efficiency was not important, why bother with a doing nay more with the electrics. That won the day for ICE vehicles, at least back in 1908 and the next few decades! While Henry Ford did plan to introduce an electric vehicle in partnership with his friend of many years Thomas Edison, battery cost make the project uneconomical at the time.
The problem so far has been to build a storage battery of light weight which would operate for long distances without recharging. Mr. Edison has been experimenting with such a battery for some time.Henry Ford, 1914.
The Addition Of ‘Stop-Start’: 1974
One of the many limitations of the internal combustion engine is that, unlike an electric motor, it has absolutely zero power when it has stopped, which means all cars up until the 1974 Toyota Crown, all combustion cars avoided stopping the engine, even when the car has not moving.
It took a while for the waste of fuel while idling to be considered a significant enough for stop-start to adopted as a common feature. In fact it took so long that at the time of the next evolution step with the launch of of the Toyota Prius Hybrid in 1997, over twenty years later, stop start systems were still rare.
Introducing the modern ‘Hybrid’: 1997.
The next electrification, and biggest step in the evolution of combining combustion and and electric motors was delivered by the Toyota Prius. Upgrading from the traditional starter motor with a fixed and low speed motor to a variable speed, intelligently controlled motor that can propel the car alone, or work together with the combustion engine was a significant breakthrough in thinking.
ICE (Internal Combustion Engine): Gasoline/Petrol or diesel.
The Case For ICE.
- Energy density.
- Established refuelling infrastructure.
1. The big plus for ICE: Fuel energy density, and therefore, range
2. Established Refuelling Infrastructure.
Internal combustion engine vehicles are ‘refuelled’, which is the same as battery swapping with electric vehicles. Refuelling requires infrastructure, and for internal combustion engine vehicles, the refuelling is all in place. Battery or hydrogen cars would take years to build equivalent infrastructure. Battery swapping networks are at least well ahead of hydrogen refuelling networks, but most battery cars fall back to ‘recharging’, which although less expensive than refuelling, is far slower than refuelling.
While battery recharging can take hours and even over a day in some cases, refuelling an internal combustion engine is a fast as a battery swap and available almost everywhere.
The end result is, in the absence of battery swapping networks, ICE cars can be refuelled everywhere, and quickly. At this time, battery swap is years from delivering the same experience, and recharging is currently significantly slower.
The Case Against ICE.
The negatives are quite well established:
- Technology problems:
- Internal combustion engines have zero power to start.
- Internal combustion is highly inefficient at best, and are rarely at best.
- Dealing with the heat also presents significant costs and and challenges to reliability.
- Reliability: delegating ‘stopping and going’ to an electric motor is more reliable.
- Very specific fuel is required, creating fuel supply dependency.
- Fossil Fuel Problems:
- Gasoline itself a known carcinogen, as are the fumes from diesel engines.
- Fuels for internal combustion engines are volatile and present a challenge to storage and significant risks in the event of an accident.
- Internal combustion engines using fossil fuels produce significant amounts of greenhouse gasses as well as toxic nitrous oxides.
1. Internal combustion engines have zero power when stopped.
A starter motor is required to start the engine. Then, to start a vehicle moving with an engine already spinning adds complexity of a clutch or clutches or a fluid drive system with significant wear.
2. Internal combustion is highly inefficient at best, and are rarely at best.
At least around 70% of energy lost as heat even under optimum circumstances. Optimum circumstances apply only during a relatively narrow ranges of engine speed, and to enable the greatest use of the narrow band of engine speeds, a complex multi ratio gearbox is required. Even with a gearbox, the result is particularly low efficiency at low speeds.
3. Dealing with that heat also presents significant costs and and challenges to reliability.
An already inefficient system, must dedicate energy to getting rid of waste heat, and requires a complex cooling system, reducing reliability.
“Hybrids are doing very well compared to traditional gasoline powered vehicles,” says Renee Stephens, Vice President of Automotive Quality Research at J.D. Power. “On average, a hybrid sees about 99 problems per 100 vehicles, compared to gas vehicles’ which have a rating of 133 problems per 100 vehicles.”Are hybrids reliable.
To put it simply, delegating a little more of the workload to an upgraded starter motor, increases reliability and
5. Very specific fuel is required, creating fuel supply dependency.
Individuals cannot simply produce, or source their own fuel. Governments who are addicted to economic activity may rejoice, as consumers are locked into spending through specific channels that enable targeted taxation of vehicle fuels, but for consumers, and fuel security, this is definitely a problem.
6. Gasoline itself a known carcinogen, as are the fumes from diesel engines.
While the internal combustion engine itself is inefficient, it is the use of fossil fuels in the internal combustion engine that produces the most significant problems. A switch to biofuels would eliminate use of carcinogens,
Fossil fuels presents bigger problems than the internal combustion engine itself.
7. Fuels for internal combustion engines are volatile and present a challenge to storage and significant risks in the event of an accident.
This results in refuelling being limited to specialised locations. Just as well refuelling is fast. If fossil fuel refuelling was to be introduced to the world today, there would be an outcry about the dangers.
8. Internal combustion engines using fossil fuels produce significant amounts of greenhouse gasses as well as toxic nitrous oxides.
When internal combustion engines are fuelled with sustainable, renewable, biofuels, the atmospheric CO2 remains in balance, as biofuel is produced in the same rate it is being consumed. The problem with fossil fuels, is that there is no process to balance the CO2 released when they are burned.
The Earth has been naturally requesting CO2 for billions of years which has kept the Earth from overheating as the temperature of the sun increased. To put the CO2 of fossils back into the atmosphere now, is to head back to the CO2 levels of millions of years ago with the higher sun temperature of today!
Conclusion: pure ICE vehicles may depreciate rapidly.
The case for gasoline cars over hybrids historically came down to “gasoline is so low price, just focus on the internal combustion engine”.
That lead to a hundred years of domination of the ICE as the sole power moving the car, and means that today the lowest cost vehicles with reasonable range are ICE vehicles. For new cars, electric cars are at the point where cost of ownership means electric vehicles make more sense at most price points, and although at lower price points electric cars are still missing, now in 2022, with lower cost electric cars coming all the time, it makes little sense to buy a new ICE vehicle. While it all comes down to price and availability, the writing is on the wall for ICE vehicles, and even purchasing a used ICE vehicle that is not some form of hybrid is best considered a short term purchase, or at least one that could collapse in value.
‘Mild Hybrids’: The first step to a hybrid.
As discussed in the basics above, a mild hybrid is a hybrid where the electric motor never powers the car over any distance without assistance from the internal combustion engine. Imagine a stop-start system where the ‘starter motor’ is engaged with the car in gear, and you have a ‘mild hybrid’. This means the electric motor provides a boost to power when starting off, reducing the lag while the internal combustion engine restarts after having been stopped at, for example, traffic lights.
If the battery becomes depleted, the car reverts to operating as a non-hybrid and can deactivate the engine stop-start. Since the batter recharges from regenerative braking, and the batter power is only used when starting, the battery charge to boost initial acceleration should be ‘free’, and available when needed, as you had to stop in order to need to start again.
The case for mild hybrids.
Although there is an additional electric battery, it is only around 40v volts and should be small and inexpensive, so with starter-alternator simplified, the cost over a non-hybrid should be minimal.
Advances over non-hybrid:
- regenerative braking reduces wear on brakes.
- improved fuel economy.
The case against mild hybrids.
How much lower price then a regular hybrid? What is the fuel consumption? In theory, these should provide a simple evolution of the ICE vehicle at no extra cost, but the improvement in fuel economy can be quite small.
The main thing stopping mild hybrids taking over from non-hybrids, is that many manufacturers have dropped development of new internal combustion engines and new engine development is only electric.
The main case against mild hybrids, is why not a ‘full’ hybrid or even ev?
- The cars is still powered only by fossil fuels.
- While more reliable than non-hybrids, less reliable than full hybrids or EVs
- Higher running costs than hybrids or EVs
On Balance: Mild-Hybrid is a mild or token improvement over pure ICE.
The running costs could in theory be reduced over pure ICE vehicles, but only marginally. Some form of ‘hybrid’ badging may be some protection against depreciation, but this would be market dependant. A mild hybrid is most competitive if buying or leasing a new a new car that would be owned for only a very short time.
Non-Plugin Hybrids, Or “Self-Charging Hybrids”.
Overview: All hybrids self charge, so what is a ‘regular’ or ‘self charging hybrid’.
The original Toyota Prius was the first modern regular, or ‘self charging’ hybrid. As all hybrids ‘self charge’ every hybrid could claim to be ‘self charging’, but this category normally excludes ‘mild hybrids’ where the electric motor never fully powers the car, and the more advanced, and more expensive, plug in hybrids, where in addition to ‘self charging’ from the ICE, the car can also be plug in charged. The label ‘plug in’ is not very helpful, but is for the hybrids between ‘mild’ and ‘plug in’, that otherwise would not have their own label.
The ‘self charging deception’ vs reality.
This is the problem with the current negative strategy against plugging in to charge. The whole campaign about “self-charging” hybrids is disingenuous at best, and potentially deliberately misleading at worst. It’s particularly sad that one of the best EVs currently on the market, the Kia e-Niro, now also has a “self-charging” Niro hybrid sibling, jumping on the bandwagon. In reality, there is nothing new about “self-charging” hybrids. They’re just hybrids, the same technology that has been available since the launch of the Toyota Prius in Japan over 20 years ago.
The worst thing of all about calling hybrids “self-charging” and implying that this makes them better than plug-in hybrids and BEVs is that it obscures the fact that hybrids do have their place. If you live in a city, don’t have access to charging, and mostly do urban miles, they still make sense for many car buyers, including taxi drivers. But if you have any chance to charge a plug-in, the PHEV is much cheaper to run, and a good battery-electric vehicle much cheaper still. So don’t be fooled that “self-charging” will somehow give you free electric miles. It won’t, and the adverts that imply this are an attempt to sell you a car that could well be much less appropriate than a plug-in for your lifestyle – and wallet.Forbes: Don’t Fall For The Self-Charging Hybrid Con
The Forbes article sums it up quite well. All hybrids ‘self charge’, a more accurate label would be ‘restricted to self charging hybrid’, and the advantage of not including the ability to charge any other way is reducing the vehicle purchase price.
In fact, if designed correctly, these ‘standard’ hybrids have the potential to be as affordable as pure ICE vehicles, and be the lowest cost vehicles equipped with an internal combustion engine. In the end, with no ability to plug in, all of the energy comes from fossil fuels, although that recovered in regenerative braking, is energy originally generate from fossils fuels that would otherwise be wasted..
The case for Hybrids & Self Charing Hybrids Over Standard ICE Vehicles.
So why bother to charge a battery, if all the energy all comes from the internal combustion engine? There are three good reasons:
- Hybrids are more efficient than ICE vehicles without the hybrid system, and can be more reliable.
- Hybrids can provide a lift in efficiency at quite low additional cost:
- A smaller capacity internal combustion engine can be provided, as peak power is achieved by the internal combustion engine boosted by extra power from the electric motor. So for example, an 200 kilowatt car could have a 150 kilowatt combustion engine, combined with a 50 kilowatt electrical motor.
- Not including other charging systems saves cost over plug in hybrids, as does the typical use of a smaller lower cost battery.
- The car can operate for short distances on electric power alone, providing silent, pollution free motoring for short distances.
The case against regular ‘self charging’ Hybrids.
- In the end, the result is still a vehicle that runs fully on fossil fuel.
- ‘Self charging’, or using the internal combustion engine to power the generator, does very little to aid efficiency in some “bumper to bumper” traffic, or on long trips on freeways, as there will be little energy available from when decelerating.
- Use of both engines together is required for full performance, but is not always available and cannot be used for extended periods, such as driving at maximum speed on the autobahn.
- Electric only range is very low at typically up to 5 kilometres or up to 3 miles, has performance usually suitable only for “shared zones” at very low speeds, and is not even available on “mild hybrids”.
- The addition of an electric motor and battery will add to weight and cost in vehicles not compensating by reducing the power of the ICE unit.
Overall, when compared to ICE without the hybrid motor, the appeal of the ‘self charging hybrid’ all comes down to how well the vehicle is priced. A plug in hybrid is a superior internal combustion vehicle, but at what additional cost given it is still a fossil fuel only car?
On Balance, Winner so far: Hybrid beats mild hybrid, and should not significantly increase price.
There is no real downside over a pure ICE or mild hybrid, particularly if combustion engine size can be reduced due to the availability of the power boost from the electric motor. Neither vehicle cost, nor weight, needs to be increased substantially over having less electric power, now the technology is mature, and it likely almost all remaining internal combustion engine vehicles would evolve into hybrids as the market moves to fully electric. It all comes down to price, and in 2022, hybrids are still the low cost choice, but as more alternatives arise, they are clearly becoming yesterdays technology.
Plug-In Hybrids or PHEV (Plugin Hybrid Electric Vehicles).
Overview: Why not just add the plug?
All that is required in theory to convert a hybrid vehicle to a plug in hybrid, is to add a charging connector and circuitry to allow charging the battery from the main power grid. From an environment perspective, power from the grid results in less emissions than running on fossil fuel power, even with the ‘dirtiest coal’ grids.
In practice, it is generally only considered worthwhile bothering to plugin and charge, if the battery can provide a “worthwhile” range when running electric only, and the electric motor can provide acceptable performance when running electric only. So plug-in hybrids tend to have bigger batteries than cars without a plug.
Ideally, moving to a plugin hybrid shifts the balance from being an internal combustion engine vehicle with added economy, to a true ‘hybrid’ of an electric an internal combustion vehicles.
The dream is a vehicle that can operate in either fully electric mode in the city, or as an internal combustion, fast refuelled vehicle on existing infrastructure when on road trips.
In theory, a PHEV provides the best of both electric and ICE power. A car that can be used as an electric vehicle on shorter distance trips consuming zero gasoline, petrol or diesel, and as regular hybrid on road trips, overcoming the range limitations of most of todays EVs.
In practice, the dream or ideal is rarely realised.
Ownership Experience: Its Not An EV, So Just Don’t Expect One.
Poor ‘Pure Electric’ experience: In practice, the ideal mix of providing the normal trips as pure electric, and reserving the Internal Combustion Engine for long trips is often unattractive because the experience in pure electric mode is too compromised. Consider, for example, the Volvo XC60 T8. 235kW of gasoline power, and 65kW of electric power. Which engine is the priority? How good is the experience when driving in pure electric mode? A comparable pure electric vehicle, the Jaguar I-Pace, has more than 4.5 times the kW (295kW) and almost 3 times the torque of the T8 in pure electric mode. Despite a comparable price, only when the T8 is fully using both engines does the T8 provide close to a similar experience.
Plug In Hybrid Identity Crisis: Is a plug in hybrid a part-time electric vehicle, or a performance boosted gasoline powered vehicle? Consider the Volvo XC60 T8. Underpowered in pure electric mode, but with sports car acceleration when using both gasoline and electric motors. While no SUV handles fully like a sports car, the cornering of the XC60 T8 is further compromised by the weight of the heavy battery. As a sports car, the T8 simply has a battery that is too large and too heavy for the role as a ‘sports SUV’, yet as a plug in hybrid, although the large battery provides the necessary range, the driving experience encourages use as primarily a gasoline powered car with extra power available from the electric power. The Volvo, and many other plug-in hybrids, are more comfortable as ‘sporty’ (or fast accelerating but heavy) gasoline powered vehicles with electric motors boost performance, rather than being suited to spending most regular commutes in ‘pure electric’ mode.
The Road Trip Benefit: The big payback for not being an EV, is that when on road trips the PHEV can become an ICE vehicle, refuelling briskly at conventional fuel stops, and never requiring a charging station. An real EV used in locations with good infrastructure, and with an EV with the range expected from 2022 models, would match the PHEV experience on road trips, but it buying a vehicle today in 2019 that will be used frequently for road trips, a PHEV could be very compelling.
If You Don’t Plug In, Some PHEVs Are Just Hybrids: Will you really plug in at home? About 50% of people are not set up to plug in at home, and perhaps surprisingly, it feels like that number rises to 90% for motoring journalists:
Unfortunately, without the ability to frequently charge, I spent most of my test time with the Outlander operating as a conventional hybrid, leaving me with 27.2 observed mpg after a week of testing.A plug-in SUV that lacks appeal: Review of a plugin without plugging in.
It may seem obvious, but if you don’t plug in, then economy from a plugin hybrid will be no better than from a hybrid that cannot plugin. Some PHEVs, such as the Volvo XC60 T8, deliver performance that will please even motoring journalists who do not plugin, but others such as the Mitsubishi Outlander PHEV, are designed for the benefit of being a PHEV to be fuel economy, and that benefit is lost if you do not plug in.
PHEV Implementation Varies: PHEVs Are New And Evolving.
- Compare the Mitsubishi Outlander, the Volvo XC60 and the Kia Sorrento PHEVs:
- Outlander PHEV uses same ICE as and adds a low power electric motor.
- Volvo XC60 T8 uses same ICE and add higher power electric motor to create a performance car.
- Kia Sorrento PHEV use 1.6Turbo motor in place of 3.0L, and adds higher power electric motor to compensate.
These are three different formulas, to defining a PHEV, and the results are quite different. This in part reflects the fact that PHEVs are much newer than conventional hybrids, with the BYD PHEV-60 and Volt PHEV launched around 10 years after the Toyota Prius. Of the formulas above, the Kia Sorrento is the most successful at achieving a vehicle that is most practical for use primarily as an EV and delivers best fuel economy even on road trips.
The case for Plug In hybrids over regular hybrids.
While a PHEV is not an EV, it does give a taste of owning an EV that cannot be experienced with a regular hybrid. There are two categories of PHEV. Those like the Volvo T8 models use the bigger motor and battery to deliver a performance result, and those such as the Mitsubishi Outlander PHEV that are focused on delivering economy.
Compared to other hybrids, plugin hybrids can offer substantially longer range, and more useable power when driving as a ‘pure’ EV, providing a taste of the potential of a full EV, and better ability to comply with pollution free zones that are in place in some European cities.
This gives three potential benefits over regular hybrids, but only performance PHEVs will provide any benefit to the 50% of the population that cannot easily plugin each night, as the economy advantage requires the ability to plug in.
Compared to ICE vehicles, plug-in hybrids offer the promise of sufficient electric range to be an EV in the city, and the range of an ICE vehicle on the highway. It sounds like the best of both worlds.
The case for Plug In hybrids over pure electric vehicles.
Given plug in hybrids in 2022 often usually a priced around the price of a pure EV, and have more to go wrong, the benefits over EVs come down to two points:
- Long range.
- road trip ability without the need for EV charging points.
In some parts of the world, EV charging infrastructure is poor or almost non-existent. For those without home charging, or who need to undertake road trips in areas with poor EVs charging points, the PHEV is the only choice. In most of Europe, China or even North America, the time of needing PHEVs is over, but it will continue to fill a need for a few years in other locations.
The case against Adding A Plug To Hybrids
The only downside over a standard hybrid to adding the plug is cost. Not only is there the charging system, but typically a bigger battery and more powerful electric motor also increase prices. Often the price is similar to a full EV, so the question arises which is better.
Compared to a full EV the downside is clearer. While reliability is still high, there is much more to break down and be maintained than with a full EV. Most people do almost all of their driving in urban conditions, and if actually driving as an EV it means dragging an internal combustion engine around all the time. Even if you can charge at home, you are still going to need to visit gas stations as gasoline/petrol goes ‘stale’ if it just sits in the tank, and having the ICE completely unused can create maintenance problems, so the ICE must periodically ‘kick in’.
The EV in the city doesn’t work like a real EV, making the price increase over a regular hybrid harder to justify.
On Balance: Add The Plug To Try an EV experience if the price Is OK.
Is the additional cost justified? It depends. In some cases the additional performance alone can justify the price, although some wanting a PHEV are seeking EV mode, not performance. The biggest caveat to the benefit of adding the plug is whether a driver has access to a plug at home. But if you have access to a plug at home, then why not a full EV? Perhaps because you are nervous about EVs and want a transition. This ‘trial EV’ role may be the biggest use case, but it is expensive, and plug sales seem to have peaked with more people going directly to an EV.
Series Hybrid or Range Extender PHEV.
Overview (to update).
With conventional PHEVs, as with conventional hybrids, both the electric motor and ICE can operate in parallel, with both engines sending power to the wheels.
Alternately labelled a “series hybrid” or “serial hybrid” or “range extender” is a vehicle where only an electric motor drives the wheels, and an ICE operates as an onboard generator to recharge the battery for the electric motor, but does not drive the wheels.
Thus a Series Hybrid is an alternative type of PHEV, which shifts the balance between ICE and EV even further to the EV. While in regular PHEVs, the ICE is the primary engine and the electric motor provides only a boost when driving at full power. As seen in the BMW i3 (not all i3 models), Chevrolet Volt from 2010 and the to be introduced in 2022 Mazda MX-30, a range extended vehicle is a full EV, and has full power even when the ICE is not in use. When the EV battery is depleted, the generator activates and generates electricity to recharge the battery while driving, enabling range beyond the range of the battery alone. Since the ICE does not drive the wheels, a series hybrid/range extender, drives as a fully electric vehicle, and offers full power even when the ICE is not running.
Most series hybrid end dropping the ICE engine all together and moving to be full electric vehicles as battery technology and charging networks improve, but series hybrids could remain viable in areas with gasoline/petrol or diesel but no charging infrastructure.
The Case For Series PHEVs over Conventional parallel PHEVs.
In city driving for local trips, a series PHEV delivers full performance without using any fossil fuel. This allows a series hybrid to operate as full EV almost all driving, given that almost all trips are are local trips.
The Case Against Series PHEVs.
Consider a PHEV with a 150kw electric motor and a 50kw ICE. As a parallel hybrid, this vehicle would have 200kw of peak power available rather than the 150kw available as a series hybrid.
On Balance: Series Or Parallel PHEV: Series PHEV.
As Toyota has correctly identified, even providing any PHEV technology leads to consumers choosing EVs, which Toyota believes is will lead to job losses and lost revenue to the automobile industry. For consumers the normal balance between road trips and local trips, and with the ability to charge at home but not road trips, a series PHEV can deliver the ultimate experience. However, it still loses on that peak power specification.
Limited ‘Pure Electric Range’: To achieve the optimal result of electric power for days with regular distances travelled, the electric range must provide sufficient distance. In 2019, vehicles with pure electric range of 40-40kms are common, but previously distance were often inadequate. In fact, 50km range, while adequate for some, does not enable this to be viable electric travel for a significant number of others.
The Case For Battery Electric
Efficiency: Batteries are highly efficient, and the entire pathway from energy supply to electric propulsion is the most efficient system available.
Charging at home: Batteries are simple to charge anywhere there is time and electricity. This allows for charging at home using the well established and efficient utility electricity grid. It has even been suggested ‘off peak’ charging of EVs could improve grid utilisation and potentially even lower electricity pricing per kw/h to homes.
Best Solution for Predominant use case: For many people, battery electric provides the optimum solution with lost cost and convenient refuelling for almost their entire use of a car, even with short range batteries. Longer range batteries are only needed by most people for very rare long road trips.
The Case Against Battery Electric.
Road Trips (Charging away from home): Charging when parked other than at home is a challenge, but one with a variety of solutions. The biggest challenge is charging during a journey. There are recharging stations, but the time to recharge means these stations would need an enormous number of bays to service the same number of vehicles currently serviced at petrol/diesel fuel pumps. Consider a current fuel stop with, for example, 8 busy pumps. If the same number of vehicles are to be refuelled, and it takes ten times as long per vehicle, then 80 ‘pumps’ would be required. Currently it can take over 20 times as long per vehicle, even with the fastest recharging, and distance per refuel is lower, so vehicles need ‘refuelling’ more often.
Internal Combustions to best cover long trips: The usage pattern discussed in ‘range’ under ‘the case against battery electric’. A 50km range needed for almost every day, but a much longer range required to cover the rare need for a longer range. The advantage of the plug in hybrid is capability for the infrequent longer range trips could be 700 or even 1,000 kms, a range not possible with any battery EV as of 2019, where over 400km range is rare, and beyond 500 not available. A further advantage is that refuelling a plug in hybrind on those longer trips is using current well established and high availability refuelling.
Range: With charging during a journey problematic, range becomes extremely important. But range comes at a cost in terms of weight. While fossil fuelled or hydrogen fuelled vehicles have carry capacity for long journeys, a large battery is heavy, and just as heavy even when not charged. A common car usage pattern would be 9 out of 10 days requiring only 50km range, and the maximum available range (for example for an electric vehicle say 400km) would only be needed less than 1 day in 30. Despite only being needed 1 day in 30, a vehicle will typically need to provide for that maximum range. This means the extra battery weight to provide the rarely needed extra 450km of range needed must be carried as ‘dead weight’ or ‘insurance’ 9 days out of 10. This ‘rarely needed’ range has a negative impact on efficiency.
Range Anxiety: Anxiety is where the worry or stress felt is beyond the level appropriate for a problem or possible problem. While balancing actual range against weight is a real problem, there is also ‘range anxiety’ is disproportionate fear of insufficient range. Imagine you had always only been able to charge your mobile phone once per week, and then were given typical new mobile, that requires charging at least every two days, and in practice most people charge every day. Switching to an Electric Vehicle is a similar change, as most people refuel internal combustion cars about once per week, so they need range for an entire week, which charging an Electric Vehicle at home is like charging a phone so enough range for two days would normally be adequate. We have been trained by past habits to need more range do to the refuelling process and the change can create anxiety. There is a real problem for infrequent long trips, and an imagined problem on normal days.
On Balance: Battery Electric
Perfect for every day use, but with question marks for the rarer days where in excess of 2/3 of vehicle range will be travelled. As most regular range EVs have around 400 km (250 miles) of range, 2/3 of vehicle range is around 250km (or 150 miles), but there are also specific ‘city’ EVs with noticeably shorter range.
For a two car family, the case is very clear for one car to be electric. But for singles or one car families, there is a question over refuelling on those long trips.
Electric cars (EVs) are, right now by far the best choice for a new car that will be kept for more than 2 or 3 years. However, there are market segments, including entry level vehicles, where electric vehicles are simply absent. In most of these segments, EVs are on the way and likely to dominate those segments by 2025, making any purchase of a new car that is planned to be kept beyond 2-3 years a difficult dilemma, where perhaps the regular hybrid becomes an option.
Plug-in hybrids (PHEVs) can provide a workable solution in the rapidly diminishing locations where EV charging is not available. A danger is the compromising by choosing a PHEV today, may give a better experience for 1 or 2 years, but lose all the appeal as charging infrastructure improves.
PHEVs are often the most expensive choice, and as battery prices decrease the price penalty over EVs will grow. Although at least as reliable as can be pure ICE vehicles, the overall ownership proposition is unlikely to add up, and buying a ‘fill in’ car until an EV is viable can be a better option.
Self-charge/regular hybrids, mild hybrids, and pure ICE vehicles, are all likely to become out of date within a few years, so the proposition all comes down to short term cost of ownership.
If buying a used car, then it is worth considering all options. If buying a new car, there is really only only one logical choice: electric. If there is no electric car in the segment, wait by delaying purchase or choosing a used vehicle.