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Old 08-01-2017, 01:54 AM   #71 (permalink)
It's all about Diesel
 
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Originally Posted by sidecar View Post
it means, as they went to the trouble to reconfigure what is essentially the Yaris 1500cc engine to Otto cycle necessary to reduce the starting load (there is no starter motor) I dont see them doing a diesel.
Indeed. Considering that a Diesel is usually harder to start, not just due to the higher compression and usually also a higher inertia due to heavier internal components, it usually also takes longer to reach the operating temperature.

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Old 08-01-2017, 02:34 AM   #72 (permalink)
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Originally Posted by cRiPpLe_rOoStEr View Post
Indeed. Considering that a Diesel is usually harder to start, not just due to the higher compression and usually also a higher inertia due to heavier internal components, it usually also takes longer to reach the operating temperature.
Ive always thought that a small continuous diesel generator, say around 3 to 4k watt and a battery bank to absorb undulations in power would be a good way to go. Possibly harder on battery though. Still if I had to start over Id be looking to go that road.

But I digress, depending on where you are driving the engine stops and starts frequently. In more undulating country driving engine off downhill, and whenever you stop. At other times you can see the engine is doing relatively little work to contribute to maintaining cruise speed.

Rolling around car parks on battery only scaring the crap out of people just doesn't get old.

Last edited by sidecar; 08-01-2017 at 02:56 AM.. Reason: additions
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Old 08-01-2017, 03:01 AM   #73 (permalink)
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Originally Posted by sidecar View Post
I've always thought that a small continuous diesel generator, say around 3 to 4k watt and a battery bank to absorb undulations in power would be a good way to go. . . .
You might want to look at the BMW i3-REx for battery, motor, and engine sizing.

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Old 08-01-2017, 03:19 AM   #74 (permalink)
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Quote:
Originally Posted by sidecar View Post
Ive always thought that a small continuous diesel generator, say around 3 to 4k watt and a battery bank to absorb undulations in power would be a good way to go. Possibly harder on battery though. Still if I had to start over Id be looking to go that road.

But I digress, depending on where you are driving the engine stops and starts frequently. In more undulating country driving engine off downhill, and whenever you stop. At other times you can see the engine is doing relatively little work to contribute to maintaining cruise speed.

Rolling around car parks on battery only scaring the crap out of people just doesn't get old.
Honda's latest hybrids do just this, but with extremely efficient gas engines - that's how the Accord hybrid works, and the soon-to-market clarity. By just using the engine as a generator, with a battery as a buffer, you can always run it at its most efficient RPM and load, giving it practically diesel efficiency due to leaving the throttle plate wide open and running Atkinson cycle.

However, the engineers also realized there are certain circumstances where the engine would deliver better economy if directly connected to the wheels, since there are conversion losses when going room mechanical to electrical, then back to mechanical energy. So, Honda also put in a light weight fixed single-speed clutched gear, allowing direct drive when the car is at the right speeds.

Reviewers were seeing in excess of 80mpg in lower speed driving conditions.
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Old 08-01-2017, 04:10 AM   #75 (permalink)
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Honda's latest hybrids do just this, but with extremely efficient gas engines - that's how the Accord hybrid works, and the soon-to-market clarity. By just using the engine as a generator, with a battery as a buffer, you can always run it at its most efficient RPM and load, giving it practically diesel efficiency due to leaving the throttle plate wide open and running Atkinson cycle.

However, the engineers also realized there are certain circumstances where the engine would deliver better economy if directly connected to the wheels, since there are conversion losses when going room mechanical to electrical, then back to mechanical energy. So, Honda also put in a light weight fixed single-speed clutched gear, allowing direct drive when the car is at the right speeds.

Reviewers were seeing in excess of 80mpg in lower speed driving conditions.

Lets go back a bit. Diesel electric locos have been around for decades, and they have successfully replaced every other railway system bar just a few speciality cases. The ethos they hold to is known as 'load balancing'. But what they are looking at is not only the loco, the whole track layout is designed to keep within the locos capabilities. The grades they encounter are designed for the train, the make up of a train is also designed to keep within those parameters.

What I would expect from an electric car would be to be able to accelerate like a banshee, but be more speed limited, not unreasonably so but quite far from 120 mph or unlimited autobahn speeds. The inclusion of the gen set is just to reduce battery weight and cost, and extend the range in ways we are all used to. As long as you feed the engine fuel, range is unlimited.

I remember Alek Issigonis saying of his brain child the Mini only needed around 5hp at 60mph to take care of the aerodynamic and frictional forces, and if you think about that you begin to realise how inefficient the IC engine power transmission system really is. I cant escape the feeling that depending on your driving needs, just going back to 'load balancing' should realise great gains in consumption in the order of 1.5 pounds of fuel per hour.

Thats around 0.2 of a gallon per hour, by a SFC for 5hp at .3 lbs per hp per hour. Achievable? .... frankly Ive no idea how much less performance that buys from what we have today or how much battery would be required to balance.
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Old 08-05-2017, 12:54 AM   #76 (permalink)
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I'm going to go look at a 2008 Prius with 313,000 miles on it in the morning. They are asking 2,900 and claim it is very clean inside and out. I may buy it if all check out right. I'll try to get at least a few hundred dollars off... the car is for my wife, but I'll still get to drive it occasionally.
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Old 08-05-2017, 03:22 AM   #77 (permalink)
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Has the engine been rebuilt? What has been replaced?
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Old 08-05-2017, 05:07 AM   #78 (permalink)
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I'm going to go look at a 2008 Prius with 313,000 miles on it in the morning. They are asking 2,900 and claim it is very clean inside and out. I may buy it if all check out right. I'll try to get at least a few hundred dollars off... the car is for my wife, but I'll still get to drive it occasionally.
the HV battery condition?
theres every chance the battery will still be good, however

car should be able to be turned on and not immediately fire up the engine. Sitting at idle it ought run about half the time or less.
Then look at the fuel mileage on the computer and see that it performs like cars in the EP guides. If its only like 37 mpg (US) its probably screwed

Also ask when the 12v battery was last replaced, or look at its tag. That also contributes to high mileage when its going down. This because if the system detects its not holding charge it will start the engine to recharge it.

Everything else about these cars is just like any other, sans look for the presence of LRR tires. Also have a look at steering joints, tire wear, shockers etc. Even a bad wheel alignment can destroy fuel economy, as it does with anything else.

lastly, good luck ...

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Last edited by sidecar; 08-05-2017 at 05:47 AM.. Reason: additions
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Old 08-05-2017, 08:22 AM   #79 (permalink)
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Not sure on condition and going to test drive it and ask a bunch of questions. The old guy that owns it told me he bought it from the 1st owner with 295,000 miles on it. They did a lot of road trips he was told. If it is mostly hwy miles, then the mileage is of little concern. I bought my daughter a 2000 Civic with 200k miles a few years ago and the car was in the condition of a car with 70k miles on it... after probing the seller I found out his wife drove 50 miles one way to work for several years. Highway miles are wonderful miles to a car.
I'll post whether I buy it or not and condition.
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Old 08-05-2017, 11:04 AM   #80 (permalink)
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Seems a bit high for the miles. A friend of mine just picked up a 2008 with ~150K for about $3000. New headlights, doesn't use any oil, hybrid battery seems in good shape. No rust, but needed a 12v battery.

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