One of the major causes of wasted fuel and excess emissions in cold climates is engines that get started many minutes before driving off in order to warm up. Actually it's not that the engines actually need to warm up, they will operate just fine when cold. It's the occupants of the vehicle and the windows that need to be heated. No one wants to get into an ice cold car and frosted or fogged windows are an obvious safety hazard. Vehicle heating systems operate by running hot engine coolant through a liquid to air heat exchanger and then route the heated air to the vehicle interior. When the engine is cold, there is no heat to transfer to the air. The answer, for most people, is to waste gas while the car sits in the driveway and let things heat up. Now, there might be another solution.

Supplier Webasto has developed a liquid heat generator that they claim dramatically speeds up the time it takes to heat the engine coolant. The generator uses an impeller spinning in the coolant to heat it by means of the sheering forces in the liquid. In principle, a driver should be able to start the car and drive off with warm air much sooner. The only question is how much extra load does it put on the engine while it's running and does it continue to run after the coolant is heated. If it does, the extra load would increase fuel consumption and negate any enviornmental benefits.

[Source: Webasto]

New Technology in Vehicle Heating Systems
from Webasto

Faster Vehicle Warm up and Defrosting; Fuel Savings and Less Pollution an Added Benefit from Liquid Heat Generator® Technology

FENTON, Michigan – Date – Near-instantaneous heat for driver comfort and improved safety from optimum defrosting capabilities in cold-weather climates will soon be a reality in the automotive industry – due to advanced technology being developed by global automotive supplier Webasto.

The Webasto Liquid Heat Generator® (LHG) will be an independent, on-demand engine heating system that is a major technological departure from the process the industry has used universally since the early 20th Century to produce heat to warm vehicle interiors.

"According to J.D. Power's 2007 HVAC Quality and Satisfaction Survey of vehicle owners, heaters not getting warm enough/fast enough was ranked seventh overall of total vehicle quality problems," said John Thomas, general manager Thermosystems Division of Webasto Product North America. "Not only was this the first time that this problem made the top 10, it was also the only one item directly impacting driver and occupant comfort. As new engine technologies designed at improved fuel efficiency take effect we can expect that this problem will only get worse."

Comprehensive testing of LHG has shown remarkable improvements in warm-up speed, defrosting performance and time-to-comfort of vehicles started from cold. Actual results depend on the vehicle, but typically LHG produces heat so quickly that defrosting starts in less than half the time current automotive systems need and often is completed before a conventional vehicle shows even the first signs of defrosting. The end benefit is two-fold – better heating than is now available in the general automotive industry, yet achieved without wasteful costs and emissions of idling engines in sitting vehicles (through the use of remote start, for instance).

Two OEMs have already shown interest in the LHG technology and what it offers consumers in an age of high-efficiency engines.

Fuel Efficiency and Customer Dissatisfaction with Heating/Defrosting Performance

The search for better fuel economy has led to significant improvements in engine efficiencies with associated reductions in heat lost from the combustion process. But, as conventional automotive heaters use this "waste" heat to warm the vehicle's interior, an undesired side-effect has been reduced heating and defrosting performance. This is particularly true of diesel engines where so little waste heat is produced that even 30 minutes of driving in cold conditions may not generate enough heat to warm the occupants satisfactorily.

More and more consumers are unhappy with how quickly the cabin will warm up, how well it stays warm and, from a safety point of view, how well it defrosts the windows.

To offset this heater under-performance many consumers resort to idling or remote-starting their vehicles before driving away, a practice already outlawed in many New England states. "Idling vehicles for long periods of time before driving down the road wastes money and fuel, puts unnecessary extra emissions into the air and it's bad for engines," said Thomas. "LHG technology produces heat so quickly that these undesirable idling habits become completely unnecessary."

How Liquid Heat Generator Works

LHG starts heating engine coolant the moment the engine is started. LHG immediately churns coolant violently by an impeller rotating within a toroid, the consequent vortices creating shear and friction, which heats the fluid.

This technology was first developed to create dynamometers to test and measure the power output and function of British naval ships' engines, but has since been widely adopted in so-called water-brake dynamometers by engine manufactures in automotive, marine and other fields. Yet unlike a dynamometer, where the heat is dumped as a by-product of the measuring process, LHG harnesses the heat for use by the vehicle's heating and ventilation system.

Market Acceptance

LHG is currently in the advanced development stage. Concept verification and testing with OEMs have confirmed the product's performance and feasibility – and the concept has been released for application engineering, vehicle integration and testing.

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