Volt to run the gas engine when the hood is opened

Daniel, don't you see how mind-bogglingly useful this feature is? In the Prius, you could be driving down the street with your hood wide open and you'd never know! The Volt will give you a warning if you are.

 

Man this thread has gotten catty! The last sentence of the story told of this feature and now you guys are having a baby about it. GM thought that this feature was needed, Toyota did not, for what ever reason. Perhaps the Volt will not keep this feature, perhaps the future Prius will have it.

 

Perhaps GM will buy Toyota. Perhaps not.

 

Best of all it won't need one of those silly noise makers slated to be installed on REAL PHEV & EV's. All you have to do is drive around with the hood up.


After this guy finished his term in the military ... I alwasy wondered if he became a GM employee.

. . . . . so much for it being safter working around the motor running.
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So you are saying that the flight deck of a carrier would be safer if the turbine engines of planes turned on and off, with the only warning being a slight whining noise? Hats off hill for mocking a guy in the military that almost got killed while serving his country!

 

The risk is that a mechanic, or owner, won't realize that the ignition is on and when they are poking around trying to fix something the engine will come on and cause injury. Such as fingers caught in belts or worse... When working on cars you frequently want the engine on while the hood is up so you can hear the bad noise, see the wobbly pulley, etc. GM's solution makes sense to me. If you want the engine off with the hood open you need to turn the ignition off, if you want it on you turn the ignition on. It's very binary, there's no gray area.

 

IMHO you're still more likely to stick your fingers where they shouldn't be even with a chirp or light than if the engine was running. I used to wrench on cars a fair amount and there were a few times I lost some skin to the spinning radiator fan (hey in all fairness I couldn't see it ;-)).

There are a number of different ways to approach this issue. Toyota puts their faith in the user (mechanic) paying attention and realizing what state the car is in. GM is supposedly (still not released yet) going to the other extreme. There's probably no wrong answer, just different design philosophies.

 

Yet, the same switch can also prevent the engine from starting with the hood up. Obviously, you're making the key point that GM had some safety motivation so your post is worthwhile. It seems that history has shown that engines usually cause less incidents when stopped compared to running. For example, someone gets under the car and has his hands on something and then someone opens the Volt hood..... Imagine the *&%$#*&$#@ issuing from under the car.

 

The inverter (Power Control Unit is the new name for 2010) and MG2 are liquid-cooled; the bottom third (Gen 2)/top third (2010) of the radiator assembly is used for the inverter while the other two thirds is used for the engine. It's pumped round by a pump that runs constantly and isn't that quiet. (Reportedly variable-speed for 2010.) If the inverter coolant is getting too hot the car can still turn the fan or fans on.

The second fan is nominally for the air conditioning but again the car can turn both on if it needs more airflow to cool the condenser down.

The wiring diagram for the three relays involved is pretty complex to allow the fan motors to run in series (voltage divided across the two motors, low speed) or in parallel (full battery voltage across both motors, high speed).

The Prius design does lead to more potential surprises if the car is left READY, because the engine can start without warning - not good if say you have your finger near a drive belt (Gen 2, obviously - 2010 doesn't have an accessory drive belt). I can understand putting some warning under the hood to say it's on, but running the engine seems crazy. In fact you could argue that engine startup ought to be inhibited with the bonnet open so you can't catch your hand in something, unless you press something to run it for troubleshooting.

Honda's hybrids do air-cool their electronics, as they only handle 10kW.

 

You *do* have a buzzer to tell you that the system is powered
up. The throttle motor. Not very loud, but definitely a
distinctive noise.
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_H*