Last Thursday, Dan Hancock, Vice President of Global Power-train Engineering at General Motors, drove to the university in a prototype automobile, and gave a lecture in Olin Hall about developmental propulsion technologies from the automobile manufacturer, General Motors. 

Hancock described three developmental programs: gas-efficient, hybrid and electric cars.

Gas-Efficient Propulsion

Automobile manufacturers may make gas-based engines more efficient by producing physically smaller, engines with less weight, which require less fuel energy to move. This goal requires an improved method to mix gas with air, and it needs a performance increase to match larger engines.

According to Hancock, air limits the activity of the engine.

“The challenge in engines is getting enough air into them. We can always get enough fuel into them, it’s easy. Fuel is very energy dense, but getting the air necessary for the right air to fuel ratio ... is the biggest challenge.”

An alternative engine, or “flex-fuel” engine, can burn either regular gasoline or “E85 fuel”, which is 85 percent ethanol with 15 percent gasoline.

The primary source of ethanol is corn, a dominate food source.  However, research strives to develop procedures to efficiently convert cellulose from non-food sources, such as waste, feed stocks and grasses, into burnable fuel.

According to Hancock, an adequate distribution system must be constructed before E85 fuels may fully fulfill consumer needs.  Currently, ethanol distribution occurs along the corn belt of the Midwestern US, but most of the US population resides along the coasts.  

Hybrid Propulsion

In contrast, hybrid cars use both gasoline and electricity. A “two mode” hybrid uses a motor in the power train, which operates most of the time, in conjunction with a conventional gasoline engine. 

This electricity currently comes from regenerative braking, where a car slows down by converting some of its kinetic energy into electricity. In Future models, as soon as next year, consumers may recharge their batteries at night by plugging them into electrical grids.

Another hybrid, called “range-extended ev”, uses electricity most of the time, but also contains a small engine that allows it to manage further distances.  

For the instance, Chevrolet Volt, debuting next November, will plug into walls at night and travel up to forty miles on electricity alone. 

According to GM studies, majority of people drive less than forty miles on their daily commutes. Consequently, using these hybrids, many people will only occasionally use gasoline. 

According to Hancock, electricity from the grid is relatively cheaper than gasoline.  Electricity costs about two cents per mile; gasoline costs about ten cents per mile.

Alternative Propulsion

Exclusively electric cars appear far off on the horizon, claimed Hancock.

The major challenge for these cars is today’s battery technology, which contains about one percent of the energy of liquid fuels per weight or volume. Using currect technologies, electric cars require enormous batteries to match the range of a conventional automobile.  

Cars with hydrogen-powered fuel cell use compressed hydrogen as a source of electricity, and then, combine the hydrogen with oxygen to produce water. 

Problems with hydrogen-fuel distribution, fuel-cell efficiency and automobile design hinder the implementation of hydrogen-powered cars.

In order for fuel cell vehicles to become a practical mode, engineers must solve these problems. They must manage the humidity inside fuel cells, and ensure that fuel cell vehicles operate in all conditions.  Automobile manufacturers must also develop an infrastructure to distribute hydrogen fuel.

GM estimates that the US requires 10 to 15 billion dollars of infrastructure investment to create 11,700 fuel stations, one every two miles in urban areas and one every 25 miles along interstates.