Engine braking on its own..good thing? (hybrid, fuel, brake)
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
I was driving a late model Santa Fe in the mountains today. As I was thinking about how to downshift the transmission for engine braking, I noticed the engine rpm shooting up. It took me a few seconds to realize that what I wanted to do manually just happened. It appears that the transmission is programmed to downshift without the driver's input. Is that a good thing? Does any other model behave like this?
A lot of cars do this. It's controlled by the computer and is an effort to save your break pads. The computer will make sure that the engine does not freeze.
Living in PA which could characterized as driving on a roller coaster in areas I'll do this manually on longer hills. There is one hill nearby I go up and down a lot that is better than a mile along, second gear from the top will allow me to coast just about all the way down. I need to slow for one really sharp curve.
I noticed my parents newer Toyota doing this, not sure I like it because it seemed to do it at times when I wouldn't necessarily be braking. Overall I'd have to reserve judgement because I haven't driven their car enough to really know. If it were hybrid recovering that energy it might be different story but seems it could be wasting energy. Not sure if it has forward sensor but if a car had one it could certainly do this intelligently.
Newer cars are designed to take away all the road fluctuation features that once caused a driver to stay alert to changing road conditions. Pretty soon there will be self driving cars....... wait, that has already happened.
I was told newer cars do this to save fuel. When you are slowing down or going down a hill, the torque converter stays locked and the transmission downshifts... at this time the fuel cuts cut off and the momentum of the car is what’s spinning the engine powering the accessories. As soon as you get to a near stop, the converter unlocks and the injectors start firing again.
So basically when you are going down a long hill, even though you hear the engine running, it’s not using any gas.
I am not sure how the engine screaming at 5000 rpm is saving fuel. I know you say fuel is shut off but I have to confirm that. Is that even possible?
If the torque converter stays locked there is a direct connection between the transmission and the engine, so it’s possible. If you’ll notice when you get slow enough, say 10mph, you can feel the engine braking sort of ‘let go’.. this is when the TC unlocks and the injectors start firing again.
I noticed it with my Sonata, and one of the smart guys over on the Hyundai forum explained it to me.
Cruise control will often keep a car in a narrow range of speeds, and will downshift or brake if you start going too fast downhill.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
