This is a photo of my new car. This was not my final choice after a long period of shopping for vehicles. It was a decision I had to make in two weeks before the insurance on my rental car ran out. On a bright, clear day when traffic was running smoothly, a young blonde woman opted to run a stop sign and knock me and my gray Hyundai Genesis across two lanes into a median. The side air bags went off. Fortunately, I was unhurt. The car, however, was totaled, bashed in on both front fenders. I am grateful for the median, or else I would have ended up in the middle of traffic.
I thought the insurance settlement was generous until I went shopping. The current car market is plagued with supply line and transport deficiencies, so the few vehicles that reach a dealer’s lot are priced exorbitantly. Ah, the law of supply and demand. The hybrid car I was interested in was $8,000 over the MSRP. $8,000!!! In normal times, you bargain for a discounted price lower than the MSRP. Not in today’s market. I ended up finding probably the only dealer in the Dallas/Fort Worth area who does not charge a markup over the MSRP, saving me thousands of dollars. I was told that the reason was because the owner, Mr. Freeman, decided many years ago that when times were bad or it was a sellers’ market, he wasn’t going to overcharge his customers, in hopes that they would always buy cars from him. Freeman Hyundai in Irving, Texas, has certainly earned my loyalty. I decided I would do my small part for the environment by buying a hybrid vehicle. Let’s learn more about them.
According to Wikipedia, a hybrid vehicle is one that uses two or more distinct types of power, such as submarines that use diesel when surfaced and batteries when submerged. Other means to store energy include pressurized fluid in hydraulic hybrids.
The basic principle with hybrid vehicles is that the different motors work better at different speeds; the electric motor is more efficient at producing torque or turning power, and the combustion engine is better for maintaining high speed — better than a typical electric motor. Switching from one to the other at the proper time while speeding up yields a win-win in terms of energy efficiency, as such that translates into greater fuel efficiency, for example.
Two-wheeled and cycle-type vehicles
Mopeds, electric bicycles and even electric kick scooters are a simple form of a hybrid, powered by an internal combustion engine or electric motor and the rider's muscles. Early prototype motorcycles in the late 19th century used the same principle.
- In a parallel hybrid bicycle, human and motor torques are mechanically coupled at the pedal or one of the wheels e.g., using a hub motor, a roller pressing onto a tire or a connection to a wheel using a transmission element. Most motorized bicycles, mopeds are of this type.
- In a series hybrid bicycle or SHB — a kind of chainless bicycle — the user pedals a generator, charging a battery or feeding the motor, which delivers all of the torque required. They are commercially available, being simple in theory and manufacturing.
The first published prototype of an SHB is by Augustus Kinzel in 1975. In 1994 Bernie Macdonalds conceived the Electrilite SHB with power electronics allowing regenerative braking and pedaling while stationary. In 1995 Thomas Muller designed and built a "Fahrrad mit elektromagnetischem Antrieb" for his 1995 diploma thesis. In 1996 Jürg Blatter and Andreas Fuchs of Berne University of Applied Sciences built an SHB, and in 1998 modified a Leitra tricycle. Until 2005 they built several prototype SH tricycles and quadricycles. In 1999 Harald Kutzke described an "active bicycle": the aim is to approach the ideal bicycle weighing nothing and having no drag by electronic compensation.
- A series hybrid electric-petroleum bicycle (SHEPB) is powered by pedals, batteries, a petrol generator, or plug-in charger - providing flexibility and range enhancements over electric-only bicycles.
A SHEPB prototype made by David Kitson in Australia in 2014 used a lightweight brushless DC electric motor from an aerial drone and small hand-tool sized internal combustion engine, and a 3D printed drive system and lightweight housing, altogether weighing less than 4.5 kg. Active cooling keeps plastic parts from softening. The prototype uses a regular electric bicycle charge port.
Heavy vehicle
Hybrid power trains use diesel-electric or turbo-electric to power railway locomotives, buses, heavy goods vehicles, mobile hydraulic machinery and ships. A diesel/turbine engine drives an electric generator or hydraulic pump, which powers electric/hydraulic motors — strictly an electric/hydraulic transmission (not a hybrid), unless it can accept power from outside. With large vehicles, conversion losses decrease and the advantages in distributing power through wires or pipes rather than mechanical elements become more prominent, especially when powering multiple drives e.g., driven wheels or propellers. Until recently most heavy vehicles had little secondary energy storage e.g., batteries/hydraulic accumulators — excepting non-nuclear submarines, one of the oldest production hybrids, running on diesel while surfaced and batteries when submerged. Both series and parallel setups were used in World War II-era submarines.
Cranes
Railpower Technologies engineers working with TSI Terminal Systems are testing a hybrid diesel-electric power unit with battery storage for use in Rubber Tyred Gantry or RTG cranes. RTG cranes are typically used for loading and unloading shipping containers onto trains or trucks in ports and container storage yards. The energy used to lift the containers can be partially regained when they are lowered. Diesel fuel and emission reductions of 50–70% are predicted by Railpower engineers.
Road transport, commercial vehicles
Hybrid systems are coming into use for trucks, buses and other heavy highway vehicles. Small fleet sizes and installation costs are compensated by fuel savings, with advances such as higher capacity, lowered battery cost, etc. Toyota, Ford, GM and others are introducing hybrid pickups and SUVs. Kenworth Truck Co. recently introduced the Kenworth T270 Class 6 that for city usage seems to be competitive. FedEx and others are investing in hybrid delivery vehicles — particularly for city use where hybrid technology may pay off first. As of December 2013, FedEx is trialing two delivery trucks with Wrightspeed electric motors and diesel generators; the retrofit kits are claimed to pay for themselves in a few years. The diesel engines run at a constant RPM for peak efficiency.
In 1978 students at Minneapolis, Minnesota's Hennepin Vocational Technical Center, converted a Volkswagen Beetle to a petro-hydraulic hybrid with off-the shelf components. A car rated at 32 mpg was returning 75 mpg with the 60 hp engine replaced by a 16 hp engine, and reached 70 mph.
In the 1990s, engineers at EPA's National Vehicle and Fuel Emissions Laboratory developed a petro-hydraulic powertrain for a typical American sedan car. The test car achieved over 80 mpg on combined EPA city/highway driving cycles. Acceleration was 0-60 mph in 8 seconds, using a 1.9 liter diesel engine. No lightweight materials were used. The EPA estimated that produced in high volumes the hydraulic components would add only $700 to the cost. Under EPA testing, a hydraulic hybrid Ford Expedition returned 32 mpg city, and 22 mpg highway. UPS currently has two trucks in service using this technology.
Aircraft
The Boeing Fuel Cell Demonstrator Airplane has a Proton Exchange Membrane or PEM fuel cell/lithium-ion battery hybrid system to power an electric motor, which is coupled to a conventional propeller. The fuel cell provides all power for the cruise phase of flight. During takeoff and climb — the flight segment that requires the most power — the system draws on lightweight lithium-ion batteries.
The demonstrator aircraft is a Dimona motor glider, built by Diamond Aircraft Industries of Austria, which also carried out structural modifications to the aircraft. With a wingspan of 53 feet, the airplane will be able to cruise at about 62 mph on power from the fuel cell.
Hybrid FanWings have been designed. A FanWing is created by two engines with the capability to autorotate and land like a helicopter.
Hybrid electric-petroleum vehicles
When the term “hybrid vehicle” is used, it most often refers to a hybrid electric vehicle. These encompass such vehicles as the Saturn Vue, Toyota Prius, Toyota Yaris, Toyota Camry Hybrid, Ford Escape Hybrid, Ford Fusion Hybrid, Toyota Highlander Hybrid, Honda Insight, Honda Civic Hybrid, Lexus RX 400h and 450h, Hyundai Ioniq and others. A petroleum-electric hybrid most commonly uses internal combustion engines using a variety of fuels — generally gasoline or diesel engines — and electric motors to power the vehicle. The energy is stored in the fuel of the internal combustion engine and an electric battery set. There are many types of petroleum-electric hybrid drivetrains — from full hybrid to mild hybrid — which offer varying advantages and disadvantages.
William H. Patton filed a patent application for a gasoline-electric hybrid rail-car propulsion system in early 1889, and for a similar hybrid boat propulsion system in mid-1889. There is no evidence that his hybrid boat met with any success, but he built a prototype hybrid tram and sold a small hybrid locomotive.
In 1899, Henri Pieper developed the world's first petro-electric hybrid automobile. In 1900, Ferdinand Porsche developed a series-hybrid using two motor-in-wheel-hub arrangements with an internal combustion generator set providing the electric power; his hybrid set two-speed records. While liquid fuel/electric hybrids date back to the late 19th century, the braking regenerative hybrid was invented by David Arthurs, an electrical engineer from Springdale, Arkansas in 1978–79. His home-converted Opel GT was reported to return as much as 75 mpg with plans still sold to this original design and the "Mother Earth News" modified version on its website.
The plug-in-electric-vehicle or PEV is becoming more and more common. It has the range needed in locations where there are wide gaps with no services. The batteries can be plugged into house (mains) electricity for charging, as well being charged while the engine is running.
Hybrid fuel (dual mode)
In addition to vehicles that use two or more different devices for propulsion, some also consider vehicles that use distinct energy sources or input types — "fuels" — using the same engine to be hybrids, although to avoid confusion with hybrids as described above and to use correctly the terms, these are perhaps more correctly described as dual mode vehicles:
- Some electric trolleybuses can switch between an onboard diesel engine and overhead electrical power depending on conditions. In principle, this could be combined with a battery subsystem to create a true plug-in hybrid trolleybus.
- Flexible-fuel vehicles can use a mixture of input fuels mixed in one tank — typically gasoline and ethanol, methanol or biobutanol.
- Bi-fuel vehicle: Liquified petroleum gas and natural gas are very different from petroleum or diesel and cannot be used in the same tanks, so it would be challenging to build an LPG or NG flexible fuel system. Instead, vehicles are built with two parallel fuel systems feeding one engine. For example, some Chevrolet Silverado 2500 HDs can effortlessly switch between petroleum and natural gas, offering a range of over 650 miles. While the duplicated tanks cost space in some applications, the increased range, decreased cost of fuel and flexibility where LPG or compressed natural gas or CNG infrastructure is incomplete may be a significant incentive to purchase. While the U.S. natural gas infrastructure is partially incomplete, it is increasing, and in 2013 had 2,600 CNG stations in place. Rising gas prices may push consumers to purchase these vehicles. In 2013 when gas prices traded around $4/gallon, the price of gasoline was $95.5 per megawatt-hour, compared to natural gas's $13.6/MWh. On a per unit of energy comparative basis, this makes natural gas much cheaper than gasoline.
- Some vehicles have been modified to use another fuel source if it is available, such as cars modified to run on autogas (LPG) and diesels modified to run on waste vegetable oil that has not been processed into biodiesel.
- Power-assist mechanisms for bicycles and other human-powered vehicles are also included.
Petro-hydraulic hybrid
The petro-hydraulic hybrid system has a faster and more efficient charge/discharge cycling than petro-electric hybrids and is also cheaper to build. The accumulator vessel size dictates total energy storage capacity and may require more space than an electric battery set. Any vehicle space consumed by a larger size of accumulator vessel may be offset by the need for a smaller-sized charging engine, in HP and physical size.
Research is underway in large corporations and small companies. The focus has now switched to smaller vehicles. The system components were expensive which precluded installation in smaller trucks and cars. A drawback was that the power driving motors were not efficient enough at part load. A British company — Artemis Intelligent Power — made a breakthrough introducing an electronically controlled hydraulic motor/pump, the Digital Displacement® motor/pump. The pump is highly efficient at all speed ranges and loads, giving feasibility to small applications of petro-hydraulic hybrids. The company converted a BMW car as a test bed to prove viability. The BMW 530i, gave double the mpg in city driving compared to the standard car. This test was using the standard 3,000 cc engine; with a smaller engine the figures would have been more impressive. The design of petro-hydraulic hybrids using well-sized accumulators allows downsizing an engine to average power usage, not peak power usage. Peak power is provided by the energy stored in the accumulator. A smaller more efficient constant speed engine reduces weight and liberates space for a larger accumulator.
In January 2011 industry giant Chrysler announced a partnership with the U.S. Environmental Protection Agency to design and develop an experimental petro-hydraulic hybrid powertrain suitable for use in large passenger cars. In 2012 an existing production minivan was adapted to the new hydraulic powertrain for assessment.
PSA Peugeot Citroën exhibited an experimental "Hybrid Air" engine at the 2013 Geneva Motor Show. The vehicle uses nitrogen gas compressed by energy harvested from braking or deceleration to power a hydraulic drive which supplements power from its conventional gasoline engine. The hydraulic and electronic components were supplied by Robert Bosch GmbH. Mileage was estimated to be about 118 mpg on the Euro test cycle if installed in a Citroën C3 type of body. Although the car was ready for production and was proven and feasible delivering the claimed results, Peugeot Citroën were unable to attract a major manufacturer to share the high development costs and are shelving the project until a partnership can be arranged.
Plug-in hybrid electric vehicles
Another subtype of hybrid vehicles is the plug-in hybrid electric vehicle. The plug-in hybrid is usually a general fuel-electric — parallel or serial — hybrid with increased energy storage capacity, usually through a lithium-ion battery, which allows the vehicle to drive on all-electric mode a distance that depends on the battery size and its mechanical layout (series or parallel). It may be connected to mains electricity supply at the end of the journey to avoid charging using the on-board internal combustion engine.
This concept is attractive to those seeking to minimize on-road emissions by avoiding — or at least minimizing — the use of ICE during daily driving. As with pure electric vehicles, the total emissions saving, for example in CO2 terms, is dependent upon the energy source of the electricity generating company.
For some users, this type of vehicle may also be financially attractive, so long as the electrical energy being used is cheaper than the petrol/diesel that they would have otherwise used. Current tax systems in many European countries use mineral oil taxation as a major income source. This is generally not the case for electricity, which is taxed uniformly for the domestic customer, however that person uses it. Some electricity suppliers also offer price benefits for off-peak night users, which may further increase the attractiveness of the plug-in option for commuters and urban motorists.
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