Toyota Prius 3rd Generation, 2010
Toyota’s 2010 Gen 3 Prius has added some incredible technology to the car itself, though although only a small amount is actually related to the Hybrid system. The fuel economy is reportedly improved over the Gen 2 by several miles per gallon. The engine has been enlarged to a 1.8L and some changes have been made to the dual motor-generator transmission to improve performance, such as reducing the weight of the rotor in MG1 to allow for higher rpm with more efficiency. In what seems like an odd technology move on a VVT-i engine, Toyota added a water-cooled EGR valve. The belt driven water pump has been replaced by an electric pump, so there is no longer a drive belt of any kind on the vehicle. The pre-heating hot water “thermos” has been replaced with a coolant system that circulates around the catalytic converter when the engine is cold, in order to raise the coolant temperature rapidly.The battery pack remains unchanged at 201 volts. Added features only mildly related to the Hybrid system include the optional solar powered air ventilation system that pulls outside air in and vents it out through a roof vent, LED taillights (lower power consumption), and the ability activate the electric AC compressor with the key fob as much as three minutes before entering the car and definitely counter-indicated as a fuel-saving device.
Honda’s New Insight, 2010
Honda’s 2010 Insight is a stand-alone platform that is a Hybrid in its own right, but no longer the impractical two-seater that was discontinued after the 2006 year-model. Its battery pack has been reduced to 100 volts but efficiency has been improved so it actually stores more energy than the previous Honda Civic and Honda Accord battery packs. Gas mileage has improved, but not quite up to Prius standards. The vehicle continues to use Honda IMA technology, although claims are made that it will operate in electric-only mode. However, when one realizes that the IMA motor is solidly bolted to the vehicle flywheel, claims of electric-only are a exaggerated. The gas engine must continue to turn, even if valve-pause closes all the valves and fuel is shut off to the injectors. The car is priced considerably less than the Gen 3 Prius and it is a solid performing vehicle that achieves excellent fuel economy.
Vehicles can be grouped into three categories that help separate the technologies. These categories are listed below.
These Hybrids have at least two electric motors. They have the capability to run on electric power only, though typically for no more than 1-2 miles. Strong Hybrids account for 83% of the market.
These vehicles include:
- Toyota Prius Still 5O% of the Hybrid market, a number that has barely changed for several years
- Toyota Camry This vehicle is the #2 seller but has lost market share since the release of the 2010 Honda Insight, which seems a bit strange as they are remarkably dissimilar vehicles.
- Toyota Highlander, Lexus RX, GX, and LH models Luxury Hybrids but together they are the #4 selling Hybrids.
- Nissan Altima This vehicle is essentially Toyota Camry technology, although the Toyota scan tool will not function on it.
- Ford Escape, Mercury and Mazda clones Best selling Hybrid SUV, it will produce solid 30 mpg numbers and is the only Hybrid tested that achieves better fuel economy in town.
- Ford Fusion Released in 2009, this car are approaching that of the Toyota Camry to become the #2 best selling Hybrid.
- GM two-mode Hybrids These include the Yukon, Escalade, Tahoe, and Silverado. Combined sales of all these vehicles represent 2.6% of the strong Hybrid market.
These Hybrids have one electric motor that is used for engine starting and assist only. Their battery operates from 100 volts to 158 volts. Honda is currently the sole manufacturer of mild Hybrids. Honda Insight 2000-2006, Honda Civic Hybrid 2003-2010, Honda Accord Hybrid 2005-2007, Honda Insight 2010. The new Insight is out-selling the Civic Hybrid. Total sales of all models provides Honda with a 14% market share. Their technology is highly effective and is less expensive, but their market share is obviously smaller than the strong Hybrids by a very large factor of 14% compared to 83%.
The BAS Systems and the 42 Volt Silverado
Currently these are only sold by GM and Saturn, taking out less than 3% of the total market. The Battery Alternator Starter (BAS) system uses what amounts to a heavy-duty alternator/starter capable of starting the engine, doing some regenerative braking, and provide about 200ms of boost from a stop. Sales continue to be poor and GM has discontinued the Malibu Hybrid, its best-selling Hybrid vehicle.
The Future: Plug-in Hybrid Electric Vehicles (PHEV)?
The plug-in Hybrid has received much attention in the press. The oldest and best-selling of the PHEV is a Lithium ion unit produced by Hymotion. This is a 5 kwh unit that recharges only via household current. Although the this battery is somewhat integrated with the Toyota HV ECU, it never receives regenerative charging from the Toyota Hybrid Synergy system. Once the battery pack is discharged, it serves no useful purpose. Another vendor, Plug-In Conversions Corp., replaces the 6.5 amp hour factory battery with a 30 amp hour battery that takes advantage of the factory Prius regeneration capability. It is said to improve fuel economy even after the plug-in charge is depleted. The cost of the units including installation is typically $1 OK and the battery pack is said to be good for 7000 charge/discharge cycles, giving: it a life expectancy of about 180,000 miles. In contrast, lead-acid PHEV conversions cost approximately half the Lithium-ion price, but have a useful life of only about 400 charge cycles, making replacement of the battery pack a necessity every two years. Given current electricity costs and gasoline costs, it is impossible to make the PHEV economically feasible, particularly during the summer when household use of electricity is high. In some areas, the cost per Kwh of electricity is based on consumption. Even with conservative use, during the summer a normal household’s use can place them in the higher cost bracket. This means additional use to charge a PHEV would come at the higher rate. Vendors of PHEV systems generally quote a low Kwh rate which assumes the household will be able to charge the vehicle at the cheapest rate in an area of very low priced electricity. At a more realistic summertime rate of 31 cents per Kwh, the cost to recharge the 5 Kwh battery for 22 miles of conservative, low speed driving is about $1.35. During this drive, the gasoline engine often operates, due to concerns about low catalytic converter temperatures. A half gallon of gasoline, which would yield 22 miles of driving in the same car, costs $1.50 at current pricing. In other words, unless the electric company would set up special pricing for off-peak hour charging of the PHEV, the conversion makes no economic sense at all. On the other hand, if the Hybrid owner had solar panels sufficient to fill all the needs of his household and extra power to recharge the battery pack, the energy would cost very little and the system might eventually be made to pay for itself. Given those facts, it is easy to understand the lack of enthusiasm by auto makers with reference to PHEV technology. The auto makers possess the technology but the small market share projections limit the development of PHEV systems.