HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
News
Electronics & Test

Slideshow: 'Start-Stop' Hybrids Hit the Road

NO RATINGS
Page 1 / 6 Next >
View Comments: Newest First|Oldest First|Threaded View
<<  <  Page 5/9  >  >>
jackiecox
User Rank
Platinum
start:'stop'hybrids hit the road
jackiecox   6/16/2012 4:56:13 PM
NO RATINGS
electricplugincars.com reports insignificant sales making economical justification for tooling up for their manufacture to likely end their availability

 

William K.
User Rank
Platinum
start-stop and fuel saving
William K.   6/1/2012 9:43:46 PM
NO RATINGS
Start-stop can be even more efficient and more convenient without the stupid programmed engine controller to make all the wrong decisions. The big challenge is the means to disengage the engine so that the vehicle can coast. The alternator that doubles as a cranking motor is the part that will need some work, mostly to assure a quickly sequenced crand-spark-fuel on sequence at each startup. The regular flywheel engaging starter would wear out way to soon, so it is not a good choice, I don't think. 

I have driven a regular car with auto trans in the start-stop mode, manually, and the improvement in economy can be close to 30% with some practice. Just add a hydraulic booster for the brakes, and an accumulator for steering and brakes, and that solves that problem. Auto restart for the engine when the accumulator runs low, and no loss problems. The big deal items are the quick clutch and the direct drive starter. Add a simple sequencer for restarts and manual control is the very best choice ever.

burntpuppy
User Rank
Silver
Re: start-stop hybrids
burntpuppy   6/1/2012 9:49:39 AM
NO RATINGS
BigDipper;

 My bus has hydraulic assisted brakes (Hydro-boost), it works off the power steering pump, if the ps hydraulic pressure is low there is an electric pump that provides the boost. It wouldn't be too hard to adapt that to a smaller car.

CliffG
User Rank
Iron
Early hybrid experience
CliffG   5/4/2012 5:16:29 PM
NO RATINGS
Interesting story about battery manufacturer pressue, but I'm guessing that today the auto mfgr's will go smaller if possible to save on weight.

I have a 10 year old, first generation Honda Insight, one of the rare manual transmissions, & will address some of the design issues they put in place two generations ago.

The IC engine does not auto-stop until it warms up, and on colder days it stays running more frequently on the in-town portion of my commute. The car does have a 12 v Kettering starter, but it only engages if I run the NiMh battery pack down too low. I think it has engaged twice in 6 years. The motor/generator in the flywheel/clutch pack does the starting: I turn the key and the engine is running.

This first gen design still has traditional HVAC so when the engine stops the HVAC fan stays running but there is no water through the heat exchanger or no AC compressor run. Sometimes I will start the IC engine if it is a long wait, no big deal. I can restart whenever I want, or swtich off the auto-stop if I want.

Electric steering boost doesn't seem to put much load on the storage, and the commonly used vacuum assist brakes are good for about 3-4 stops with the IC engine off. It restarts if the vacuum goes too high. (How many times do you need to start, then stop without the engine?) This first gen does not move on electric motor alone: Honda designed an assist approach, not a parallel one.

Lots more, but in summary: the sytem is pretty flawless, no excessive wear on the Bendix, instant restarts because the egnine is up to speed right away, electric HVAC would be a big plus, as would some power in this case: a 3 cylinder 1 liter engine is not the best choice for SanFran area traffic, although the 5 speed manual helps.

My other car is getting replaced this year, probably will be a diesel or something with a stop/start, even if not a hybrid. In my daily commute I would save idling about 7 to 10 minutes, twice a day.

Sven
User Rank
Iron
Re: Missed mpg opportunity
Sven   5/4/2012 12:00:40 PM
NO RATINGS
There is a reason for the torque converter dragging when decelerating as opposed to disengaging and letting the engine idle.  Not all Auto companies have adopted it i.e. if you drive certain Chrysler products they coast freewheel style when you take your foot off the gas.   If you drive a Honda (and other brands) when you let off the gas you feel the engine braking.   Since the 90's Honda has shut off the fuel injectors during deceleration to save fuel, when you hit the gas again the fuel injectors turn back on.  The torque converter stays connected to the engine to keep the engine turning--while it's just pumping air.

BigDipper
User Rank
Iron
Re: start-stop hybrids
BigDipper   5/4/2012 11:11:53 AM
NO RATINGS
Non power brakes are not an option with disc brakes - too much pedal force is required, unlike the drum brakes of old.  Some manufacturers, Daimler Benz comes to mine, have been experimenting with electric power brakes. 

Bunter
User Rank
Platinum
Caution on MPG claims.
Bunter   5/4/2012 9:27:46 AM
NO RATINGS
I think the theory on start stop has potential but some recent road tests I have seen have raised questions about the current state of the art.

The Malibu ECO (start/stop: eAssist)has been in two comparison tests against other mid-size sedans (Motor Trend and Edmunds IIRC) and has not demonstrated any mileage advantage in either case.  The testers also found the system rather intrusive as I recall.  The EPA estimated advantage isn't there apparently.

Over the years I have found that EPA milage ratings provide a rather poor basis for real world comparisons.  Features that will do well on the govt treadmill don't always translate to an advantage on the road.

 

Some thoughts.

Dennis

Thinking_J
User Rank
Platinum
another approach....
Thinking_J   4/3/2012 5:09:56 PM
NO RATINGS
A few years ago... a vendor of mine (I am in the electronics industry) told me of the engineers he was working with at one of big American car test tracks he visits regularly (in our area).

Their focus : reduce size of battery required in cars.. saving costs on battery

The engineers told him they had worked out the details on "instant" start on their engines.  These engines had most of the engine management requirements being described for Start/Stop.. but had NO starter required. Because the ECU "knew" the crank position, it could fire up the engine by directly injecting fuel into appropriate cyclinder and fire it - starting the engine from a stop. They demonstrated working units, everything was going fine .. then...

The idea was dropped.

Reason: some of the battery companies got wind of the project and threaten to charge as much for the much smaller batteries as the larger batteries... killing most of the incentive for the change.

Apparently the viewed risks of eliminating the starter (public perception) and the additional costs required of the ECU/additional sensors and valve controls at that time.. were not enough to offset the elimination of the starter.

Maybe this idea is finally seeing it' time "come"?

Thinking_J
User Rank
Platinum
legal issues and "quaint" folks
Thinking_J   4/3/2012 4:43:53 PM
NO RATINGS
S/S .... I have every confidence any remaining issues will be resolved. Will it matter (be enought?) is another subject.

However, I have not seen any discussion/mention of the legal issues of implimenting it.

It is eligal in many states (mine included) to allow a car to "coast" on public roads (unless it is unavoidable - as in engine failure).Enforceablity of such a law is questionable (as is many laws).

Basically, a well meaning attempt at improving public safety, because it was viewed as a "un-safe" practice by people that were more concerned with the cost of fuel when cars / trucks had become widespread (1910-1930).. but costs were critical (during depression).

think :

ma and pa kettle.... coming to town, with some quaint ideas on being frugle and causing some "disruption" to the town folk's traffic. Because the law (in this state) was inacted before power steering/power brakes was common place, this was the only explaination given to me that made any sense. (told to me during traffic safety class when asked on the subject - coasting via clutch disengagement)

Every state has some laws on the books - from another era - that should be removed.

 

 

donevol
User Rank
Iron
Missed mpg opportunity
donevol   4/3/2012 3:30:49 PM
NO RATINGS
I agree with the basic idea of starting and stopping the IC engine when it is not needed in a hybrid but there are is another opportunities right now with conventional vehicles that is being overlooked. In the quest for fewer losses in the automatic tansmission the designer monkeys have tightened up the torque converters so that there is significant "engine braking" everytime one lets up on the foot feed regardless of what 'gear' it is in. Why doesn't the sense all and do all computer controlled engine and transmission controls have the smarts to monitor the foot feed and simply let the car coast? Manually slipping into neutral lets the engine run at idle, with less gasoline consumption, while the car just keeps rolling along. I can always use the brake when I want to slow down or stop and put it back in gear to accelerate. Slipping the car in and out of neutral during my daily commute through stop and go city traffic with gentle rolling hills increases my mileage by several mpg.

DonV

<<  <  Page 5/9  >  >>
Partner Zone
Latest Analysis
Some humanoid walking robots are also good at running, balancing, and coordinated movements in group settings. Several of our sports robots have won regional or worldwide acclaim in the RoboCup soccer World Cup, or FIRST Robotics competitions. Others include the world's first hockey-playing robot and a trash-talking Scrabble player.
Sherlock Ohms highlights stories told by engineers who have used their deductive reasoning and technical prowess to troubleshoot and solve the most perplexing engineering mysteries.
Melissa Cavanagh of 3DP Unlimited talked to Design News about the company’s large format 3D printer, during Medical Design and Manufacturing Midwest.
The DDV-IP is a two-wheeled self-balancing robot that can deliver cold beverages to thirsty folks on hot summer days. A wireless RF remote enables manual control of the device beyond the act of self-balancing. All of the features of the DDV-IP result in an effective delivery vehicle while providing entertainment to the user.
Eric Doster of iFixit talks about the most surprising aspect of the Microsoft Surface Pro 3 teardown. In a presentation at Medical Design & Manufacturing Midwest, iFixit gave the Surface Pro 3 a score of one (out of a possible 10) for repairability.
More:Blogs|News
Design News Webinar Series
10/7/2014 8:00 a.m. California / 11:00 a.m. New York
9/25/2014 11:00 a.m. California / 2:00 p.m. New York
9/10/2014 11:00 a.m. California / 2:00 p.m. New York
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Oct 20 - 24, How to Design & Build an Embedded Web Server: An Embedded TCP/IP Tutorial
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: 10/28-10/30 11:00 AM
Sponsored by Stratasys
Next Class: 10/28-10/30 2:00 PM
Sponsored by Gates Corporation
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service