Slight engine shudder on 0mph acceleration
 

Re: Slight engine shudder on 0mph acceleration
 

If you're sitting on a flat surface, stopped with the internal combustion engine (ICE) off, if you put your foot (slightly) on the accelerator, you'll be using battery. As soon as the laws of physics kick in (that is, trying to move a 3000 pound?? car from a dead stop on battery alone would require more power...especially if you're pointed uphill) the ICE turns on...and that's what you're feeling.
The ICE turns on about 1/4 second after you press the accelerator and the car senses it needs more power.

If you are on a downslope (gravity helping you), the ICE might not turn on, the battery will provide the power needed...unless you 'gun' it.

If the ICE is running while you are sitting at the stop (assuming it's cold and the engine isn't totally warm) and you press the accelerator, the ICE will power the car and you will NOT feel the 'shudder', since there's no transition from battery to ICE.

This is normal.

Re: Slight engine shudder on 0mph acceleration
 

Hi Haroldo- Thanks for the swift reply. An engine shudder from a 4cylinder 2.0(?)L engine was not common in my '83 4cyl. Camry and is not common in my friend's 2.4L 2009 Corolla. If the fuel injection and idle ratios are correct and all the computer output is working correctly this car should not shudder, but give the smooth acceleration Toyota engines are noted for, including a 3000lb. weight load in the equation. I extrapolate to a 2010 TCH and believe this should still hold true-no shudder for a proper smooth exchange of torque and velocity for a well engineered Toyota product-especially as my friend's 2007 TCH has no shudder when pointed up a hill,too.
In the old days of points and condensers and timing points if a car shuddered at start-up, a smart mechanic or amateur tinkerer would adjust someting, including the carbeurator, timing or spark gap,etc. These days the adjustments are out the hands of lay people. What to do next?? HaroldTCH

Re: Slight engine shudder on 0mph acceleration
 

Have you actually driven your friends car under the exact conditions that you experience the shudder in yours? Or is the friend telling you that the shudder is not noticable?

I have owned a 2007 TCH for 60,000 miles and now have a 2009 TCH for 10,000 miles. The shudder is there in both. We pass it off a regular feeling in the hybrid, and it tends to become less noticable. If you understand what is causing it, as Haroldo explained, I would imagine it will become less noticable to you as well.

The shudder is just the gas engine starting up, after it was shut down at the stop.

Re: Slight engine shudder on 0mph acceleration
 

Thanks again to the TCH owners who have told me the slight shudder is normal. I will go with the flow and with time and as statistically more replies telling me it too, is normal, will forget about it. I just think Toyota could have engineered this slight annoyance out of an otherwise great concept brought to reality. Harold TCH.

Re: Slight engine shudder on 0mph acceleration
 

HaroldTCH,

You need to do a LOT of reading and understand how the TCH (and Toyota's) system works. If you think this is harsh, try a Honda IMA system. Considering the gas engine is STOPPED, it is being spun up to around 1,000 rpm, the ECM waits until the oil pressure is up and then feeds fuel and spark to the engine and allows it to start. All of that in the space of a second or so.

Try looking at this site and play with the graphics to understand how the power split device works. Grab the three circles on the MG1, ICE and MG2 graphs and move them to see the relative changes to the rpm's of each and the speed of the car. Also watch how the electric motors will spin in reverse if required to attain the right speed and engine rpm.

Toyota Power Split Device

Re: Slight engine shudder on 0mph acceleration
 

It has nothing to do with fuel injection or mixture. It has to do with starting the engine. Each time the engine is turned on, or off, the machinery makes torque, which causes a little bit of motion in the machine, which you feel as a shudder.

Your '83 Camry, and your friends '09 Corolla, both have some shudder when the engine starts. But they only start the engine once, when the car is turned on.

The TCH does not turn the engine on right away when the car is turned on. Instead, it turns the engine on when the power from the engine is needed, and turns it off again when that power is no longer needed. The computer can turn the engine on and off many times during a 20 minute drive in traffic.

The shudder is caused by the machinery as it the engine spins up to speed and then starts. One of the big electric motors spins the engine up to speed, and then the computer turns on the fuel and spark to actually start the engine. That sequence of events makes torque, which you feel as a slight motion or shudder.

If it bothers you, just remember that you are not paying for fuel whenever the engine is not running. As you drive the car over the first several thousand miles, you gradually get used to it, and then you barely notice it.

Re: Slight engine shudder on 0mph acceleration
 

...to add to that...
Gas only vehicle's engines turn on when the car is in park (or neutral, if using a manual transmission).
Hybrids engines (when warm) will turn on when the car is 'in gear'.

Re: Slight engine shudder on 0mph acceleration
 

For all the excellent info on the engine start-up slight shudder: I get it!! It is not the torque load on an active engine (aka: idle rpm), but a neutral torque 0rpm start up which is almost simultaneous( ca. 1sec. )with the transmission torque load. The engine to transmission connection does not make the engine shudder. Engine start up shudder I can live with. Thanks to all for the comprehensive explanation. HaroldTCH:angel: