Hybrid cars and Starters
- Thread starter ZZman
- Start date
- Status
Depends on which hybrid, most just use the electric propulsion motor so turning over the engine is no work at all for them.
JHZR2
Staff member
I was under the impression that there was not a starter...
No starter motor on the Toyota hybrids. Not sure about other makes, but I would guess not as well.
Interestingly, no alternator either, belt driven power steering pump or belt driven A/C compressor (except on first gen Prius).
Also, the electric motor responsible for starting spins the engine up to operating speed before firing it up, so I 'think' oil pressure is already built up before the cylinders start firing.
Interestingly, no alternator either, belt driven power steering pump or belt driven A/C compressor (except on first gen Prius).
Also, the electric motor responsible for starting spins the engine up to operating speed before firing it up, so I 'think' oil pressure is already built up before the cylinders start firing.
Originally Posted By: mareakin
here's a good question: WHY do Hybrids HAVE *TWO* batteries?
one hybrid battery (big 300 lb. heavy one) and a regular car-battery (the small one)
Small battery is used to power up the computers which are responsible for co-ordinating the whole ballet of hybrid/gas engine interaction. Just a guess, but probably the computers need to check that all is OK with the hybrid system before just drawing power from the big battery. Hence, they get power from the 12 volt battery, do their checking, and then activate the hybrid system.
Also, in accessory mode (i.e. running radio, cd, dvd with ignition off) the auxilliary battery is used. Once the computers are powered, the main (traction) battery is used. Interestingly (see above post) the main battery then recharges the 12 volt battery as there is no alternator.
In Toyota speak, the 12 volt battery is the 'auxilliary' battery and the main hybrid battery is the 'traction' battery.
here's a good question: WHY do Hybrids HAVE *TWO* batteries?
one hybrid battery (big 300 lb. heavy one) and a regular car-battery (the small one)
Small battery is used to power up the computers which are responsible for co-ordinating the whole ballet of hybrid/gas engine interaction. Just a guess, but probably the computers need to check that all is OK with the hybrid system before just drawing power from the big battery. Hence, they get power from the 12 volt battery, do their checking, and then activate the hybrid system.
Also, in accessory mode (i.e. running radio, cd, dvd with ignition off) the auxilliary battery is used. Once the computers are powered, the main (traction) battery is used. Interestingly (see above post) the main battery then recharges the 12 volt battery as there is no alternator.
In Toyota speak, the 12 volt battery is the 'auxilliary' battery and the main hybrid battery is the 'traction' battery.
Last edited:
My colleague has a company-issued Ford Escape Hybrid. It also uses the propulsion motor for spooling up the petrol engine. Listening to it "start" is kinda weird as it doesn't make the usual "engine-starting-up" sounds. You turn the key and the petrol engine is just suddenly running.
Originally Posted By: rcy
Also, the electric motor responsible for starting spins the engine up to operating speed before firing it up, so I 'think' oil pressure is already built up before the cylinders start firing.
Sounds like an extended cold start to me. I don't know how much I like that idea. Cold start wear is occuring when the engine is spinning whether or not combusting is taking place at the time.
Also, the electric motor responsible for starting spins the engine up to operating speed before firing it up, so I 'think' oil pressure is already built up before the cylinders start firing.
Sounds like an extended cold start to me. I don't know how much I like that idea. Cold start wear is occuring when the engine is spinning whether or not combusting is taking place at the time.
Good point...of course I could be completely wrong on how it starts...I'll check my shop manual when home and see if there's any info on it.
Hmm..can't find anything on Google...was sure I read somewhere about how it starts. Could be I was wrong, and maybe it just starts like an ordinary car (just no starter motor).
Cold starts and hot starts are not the same wear wise. Most of the stop/start enabled vehicles I have driven do not stop the engine the first time until it is up to operating temp. At that point everything is coated in oil and the system is essentially primed - only one cold start.
Hmm. Spinning the engine up to speed before applying combustion force? To me, that sounds like a great idea. Fully lubed bearings before load is applied?
Honda's IMA system uses the electric motor/flywheel to start the engine. Driving a last-gen Civic Hybrid (the ones without the battery issues) is weird compared to driving a normal car. The engine will cut out below 5 mph and every time the car's stopped. It's very noticeable on that CVT-equipped car. One second the engine is on, the next the car is silently coasting up to the light with the engine off.
In the case of GM's 2mode system there are 2 batterys due to 2 electrical systems. 12V battery (regular type) for the gas engine and body accessories and the 300V for the electric drive motors and hybrid system. The AC compressor is electric and runs off the 300V battery so ac works even with motor off.
there is a hidden button in the escape hybrid (toyota system), under a small cover on the dash, IIRC driver's door must be open to access. it allows the 12V battery to provide a jump to the 140V propulsion batt if it is for some reason drained, through a step-up inverter. Think it's good for two jumps before the 12v batt is depleted. there is no regular starter on the ford...
Do these cars have alternators, or do both the 12v and 300v systems charge off the drive/charge motors?
In my hybrid (Lexus RX400h) the traction battery (288 volts) is charged by the electric motors (front and rear (with AWD), during regenerative braking or when the ICE (internal combustion engine) is powering the front electric motor (which can recharge the traction battery, power the front wheels or do both) There are actually two motors in the front - MG1 and MG2, MG1 acting as a starter and a pathway for power to the wheels, MG2 generating electricity to drive the front wheels (via MG1 I think) or recharge the traction battery.
The auxilliary (12 volt battery) is charged from the traction battery.
The auxilliary (12 volt battery) is charged from the traction battery.
Originally Posted By: Jim 5
Do these cars have alternators, or do both the 12v and 300v systems charge off the drive/charge motors?
I think the Toyota/Ford/Nissan and GM/Allison systems have a 12V feed from the inverter to charge the 12V battery and the accessory feed.
And Toyota in Japan had a emergency charger for the Prius as well - although you can "jumpstart" a Prius from the 12V jumper cable "tab" in the engine bay fuse/junction box to boot it when the auxiliary battery is dead.
Do these cars have alternators, or do both the 12v and 300v systems charge off the drive/charge motors?
I think the Toyota/Ford/Nissan and GM/Allison systems have a 12V feed from the inverter to charge the 12V battery and the accessory feed.
And Toyota in Japan had a emergency charger for the Prius as well - although you can "jumpstart" a Prius from the 12V jumper cable "tab" in the engine bay fuse/junction box to boot it when the auxiliary battery is dead.
Most hybrids don't have a conventional starter or charging system. It's accomplished with the motor/generators in the transaxle assy. The electric motors can also act as generators (hence the name MG1 and MG2)so the same generator that recharges the batteries can start the engine. The Motor/Generator is usually permanently coupled to the engine so you don't have a traditional ring gear for the starter. It cranks the engine by directly rotating the crank shaft. (just like push starting a car with a standard transmission)The engine also cranks over much faster (800-1000 rpm vs 120 rpm) so they sound much different when starting.
I'm not aware of any prelubing of the oil system but some of the Prius hybrids can preheat the engine cooling system prior to start up.
I'm not aware of any prelubing of the oil system but some of the Prius hybrids can preheat the engine cooling system prior to start up.
- Status
