eleman73

Hello
One of my friend who is an expert on cars especially engines told me today that he is against hybrid tecnology for this specific reason;
He said " engine gets more damege and age when it starts in the mornings while it is cold. he said that in the hybrid vehicles unless there is a system keeps the engine lubricated when it is driving on electric, the oil stays at the bottom of the engine department and suddenly when the ICE kicks in it starts with non-lubricated engine. He advocates that if there is no system like oil pump that keeps ICE oiled when it is not running, it is too harmfull to the engine.
Does anyone knows if there is such systems on our cars? honestly I did not answer him about his question. Please help
Thanks

Lil4X

I hadn't heard that particular question, but here's a guess: From a cold start, turning the hybrid's key will always crank the engine for a number of reasons - to bring the engine up to operating temperature, circulate oil, top off the batteries from the overnight discharge, and warm the cabin - just like any normal ICE driven automobile. Only after all of this has been accomplished will the hybrid's engine shut down when the vehicle is stopped in traffic.

While it is true that a large proportion of engine wear comes during those first four or five seconds after a cold start before oil is circulating - especially through the valve train at the top of the block, today's lubricants are designed not to run off critical areas, cam bearings, tappets, etc., after shutdown for just that reason. This is common to all engines - not just the ICE in a hybrid vehicle.

Once the oil is circulating, and especially after the engine reaches operating temperature, there is no reason to continue to circulate oil when the engine is off. You wouldn't circulate oil through the block for ten minutes after you parked the car and walked away, neither is it necessary to circulate oil when the vehicle is moving solely under electric power. Most hybrids switch off the ICE when the vehicle is stopped, and start rolling under light throttle applications and relatively low speed under electric power only for moderately short distances. Naturally this all depends on the programming of the power controller, but current hybrid vehicles do not spend great lengths of time or travel great distances powered only by the electric motors, so there is plenty of warm oil still in place, even in the top of the cylinder head when the engine restarts.

Your friend may be thinking about pre-oilers designed to pump oil to the top end of the engine before starting, but in automotive service with modern lubricants, these have proven inconvenient and of little practical use. Post-oilers used on some turbocharged engines that continue to circulate oil through the exhaust turbine bearings for several minutes after shutdown to prevent "coking", or carbonizing the oil in the hot turbo until it has had an opportunity to cool down a bit have largely fallen out of favor as well, most turbos no longer require this precaution thanks to synthetic oils, but it is still common on large industrial engines.

widlfiresd

With Prius' on the road with over 200k on the odometer, I don't think it is an issue.

Also, mail trucks, FedEx, UPS, stop and go constantly.

Rockville1

No, no, no. This is not an issue of hybrid engines at all. In fact, your friend has got it completely backwards - hybrid cars have less wear and tear on their engines than do standard non-hybrid cars. Do you really think Toyota, Lexus and Honda are going to put out hybrid cars that are going to break down faster than a standard car? Come on!

First of all, the hybrid cars use a pre-lube system for cold starts. That is when you first turn the car on, even on very cold mornings, the internal combustion engine (ICE) will not start for about 7 seconds. This is because the engine is being pre-lubricated. Second, when the ICE does start, it is directly driven by one of the electric motors and the ICE comes on immediately at 1,000 rpm in a nice pre-lubed environment. There is no starter, no flywheel and none of the complicated linkages to get the engine moving (thus less things to wear out). Standard cars typically start at about 100 RPM and with no pre-lube and it takes a few seconds for the oil pump to get cranking and lube the engine. This puts a lot of stress on a standard non-hybrid car ICE. Not the case with a hybrid ICE.

As for the constant on-off of hybrids - all cars, whether hybrid or not, once the engine is warm, the engine remains lubricated for quite a long while after the engine is shut off. The oil does not immediately flow straight back to the pan. So the fact that the hybrid ICE engine is pre-lubed, directly driven by an electric motor that eliminates the combersome and complicated mechanical linkages, and is always started at a minimum of 1,000 rpm reduces stress and wear and tear on the engine.

MadloR

What? Are you sure about this? I have never heard of any OEM product that "pre-lubes" an engine (aka, priming, raising oil pressure prior to an engine start) and that is factory equipped on any Hybrid or non-hybrid vehicle.

As well, an engine cold start on a Hybrid or non-hybrid, all things being equal (temp, oil weight etc.) has the same effect, same wear and tear. After an engine has already been started, and has run, the restart after a shutdown of a fully lubricated engine is next to nil. All parts have been brought up to temperature and have been fully lubricated. The stop, start, stop is nil. The added wear and tear is probably on the starter, IF anything else. Of course, I wouldn't doubt that the manufactures of hybrid vehicles have not beefed up the starter motors as well.

Cheers,

MadloR

Rockville1

Yes, I'm sure, but I will try and clarify my answer to avoid any confusion. What happens in a standard, non-hybrid ICE engine on a cold start is that the the spark and combustion happen as soon as the pistons begin to move. It is the combustion and resulting high pressure on the piston BEFORE the oil pump has time to lube the cylinder that is hard on the engine. Once the oil pump is pressurized, then it can send oil to the engine and everything is fine.

In a hybrid ICE engine, the electric motor spins the engine up to 1,000 rpm BEFORE ignition and combustion occur. Thus, the pistons are not under any pressure from ignition until they are already spinning at optimal rpm. Also, because the engine directly drives the oil pump, the oil pump is pressurized and lubricating the engine before combustion ever occurs (thus the prelubrication I was referring to).

I agree with you on your second point that once the car is warmed up, there is less wear and tear, whether it is a hybrid or not. You also mentioned starters - remember that hybrid cars do not have starters - they don't need them as the electric motor directly drives the engine (thus less wear and tear).

It is also worth mentioning that hybrid cars have introduced a lot of new technologies to engines, including use of light-weight and stronger materials that further reduce wear in the engine.

The issue of less wear on the hybrid engine is also discussed in this Wikipedia article on the Prius:

http://en.wikipedia.org/wiki/Toyota_Prius

I hope this helps, and I apolgize for any confusion.

MadloR

There are aftermarket accessories called "Pre-Lubers". They in fact work prior to the engine or any of the components actually moving. They are electrically driven, and draw oil from the oil reservoir and pump it under pressure hence priming the engine with oil prior to the actually engine components from moving.

I now understand what you said, but your initial reply gave me the impression of the following... an actually preluber.

On the side note, I never knew that the engine actually turned over without air, fuel and spark prior to actually turning over when performing "restarts". Very cool.

Cheers,

MadloR

Rockville1

Yeah, I knew once I read your initial response that my post was not very clear.

The hybrid systems are indeed very cool and very well-thought out. The hybrid cars are not new technology anymore - they have been around long enough to prove their reliability. I think all cars will be incorporating the hybrid systems in the very near future. It just makes so much sense!!!

spwolf

rock, whats up with the name? Any insight with LS600h or RX Hybrid? Cmn rock, spill some beans, sell some cars :-)

Rockville1

It's Rockville1 because I live in Rockville, MD.

I can't offer you any insight on the LS600h - but I do own an '07 RX400h and I love the vehicle! I have posted a bit on different threads about the vehicle and about hybrids in general. As you might glean from my posts, I'm pro-hybrid!

clexusking

Real Rockville where are you? It seems you have an imitator. One that rivals your knowledge. Possibly a co-worker? We want Rock, we want Rock.

Rockville

even if he is using a similar moniker.

The RX400h uses a motor/generator (MG1) to start the gas engine. It spins on due to the powerful motor. MG2 drives the front wheels and MGR drives the rear wheels independently. There is no physical connection between the front and rear drives. The hybrid motor/generators and the hybrid battery all carry an 8 year/100,000 mile warranty. I haven't heard of a motor failure yet.
The pollution emissions are reduced by the gas engine turning off during stop and go traffic. When the RX400h is turned on it just says "ready" in the power meter. A few seconds later the gas engine will power up and stay on to heat the catalytic converter and coolant to running temperature. After that it will turn off and on when necessary. The electric motors become generators when coasting or slowing down and send electricity back to the hybrid battery (alkaline nickel metal hydride gel type). This eliminates the need to charge it by plugging in like a full electric. The RX400h makes enough power to walk away from most V8 SUV's. It gets much better fuel efficiency and one last thing... It has VDIM which can deal with freezing rain, ice and changing conditions so you don't have to. It is one of the best features on the vehicle and not available on the conventional RX, GX or LX models.

Rock (the original Rockville)