Honda Accord Hybrid: 50 MPG City - clone Toyota

It has a clutch. THS doesn't. Both are fixed ratio.

 

THS is not fixed ratio since the motors change their speeds & thereby change the gear ratio between the gasoline engine and the wheels.

In contrast the Accord hybrid has a direct drive motor (like a Tesla or Leaf... no gears or transmission). Similarly the engine ties directly to the wheels... no gears or transmission.

The THS has a planetary GEAR system (aka transmission) while the HAH has no gears. No trans. . BTW the Volt works the same way..... direct drive to the wheels with no 1st, 2nd, 3rd, etc gears. No variable ratios either.

 

Can't agree.

THS has fixed ratios, final drive is related to motor MG1 speeds (freedom degree).
HAH has a clutch, and MG1 makes a electric drive (freedom degree and a discrete value).
Volt has 3 clutches, and a fixed ratio like THS (very similar, but allows multiple modes)

 

Hello..... since the Prius engine can spin slow or fast, even if the speed is held constant, that means it has a variable ratio engine-to-wheels. (In contrast the HAH has a fixed ratio when its engine is connected to the wheels. It never changes.)

Also the planetary gear system in the Prius is obviously a transmission. Planetary gear systems have been used for auto transmissions for decades. The Prius trans is essentially a 3-speed auto-trans without the clutches.

The HAH has no transmission.
That eliminates a lot of losses.

 

The Honda has a transmission in the same sense that the planetary headset is a transmission. A transmission is the method of transferring power from the motor to the wheels. Full hybrids like the Toyotas, Fords or HAH don't have a traditional transmission, but they still have a way to transfer power to the wheels.

 

"When", means a parameter set by a clutch device.
It's nonsense insisting it has no transmission!

Well, you are intitled to your opinion, as many reviewers are also, it simply doesn't mean being a correct one.

 

Can you ellaborate on this "less losses" when the clutch is open?

 

Does the Tesla have a transmission? I've seen the torn-down car in the store, and the motor runs directly to the wheels. It has nothing I would label as a transmission.

By "no losses" I am referring to a car that has no transmission. No torque converter, no trans fluid inducing parasitic losses (fluid resistance), no ~100 pounds of rotating mass, etc.

 

Agree.

Well, you might get 100+ pounds of rotating mass in HAH...
Clutch + motor rotors... and two gears...

 

Like the Tesla the HAH motor runs directly to the wheels... no transmission. Ditto the engine.

BTW I noticed new HAH owners saying they don't know the best speed for max MPG. For highway driving I would guess its 40 or 45 miles/hour..... same as all Honda's other hybrids (insight, civic, accord G1, CRZ). That puts a Honda engine at 1500 rpm.

 

It's your guess. As many others, you keep your opinion based on "whatever"...

2014 Honda Accord Hybrid Has No Transmission: How It Works

"To be more precise, there's nothing in a form we'd normally recognize as a transmission—no conventional automatic transmission, no automated dual-clutch system, no belt-and-pulley continuously variable transmission (CVT) either. There's no torque converter, either—not even a drive clutch to slip the engine from a standing start."

First off all: IT HAS A CLUTCH!

Second: HSD has nothing of the above, and NO CLUTCH!



Whatever, Troy!

 

does tesla have a noisemaker?

 

A standard automatic has multiple clutches. The quote from the article is correct. Honda's two motor hybrid doesn't have a drive clutch. The article does talk about the clutch it does have.

This multi-mode hybrid is about as close to direct drive as is physically possible. There is a chain of gears to transmit the motor and engine output to the wheels. That is a true even with BEVs. Unless they are using hub motors, and I am not aware of any of the current ones available that do.

This fix ratio set of gears will be cheaper than a typical transmission and likely the planetary gear set in the HSD. In EV and hybrid mode, only the one motor has physical connection to the wheels. The only way to vary wheel speed is to vary the motor speed. There is no way of manipulating the the gears to vary the ratio between the wheels and motor.

When the engine is engaged, it is driving the same gear set as the motor. Still just a fixed ratio. The motor can add power to assist the engine, but its input can not adjust the ratio or cause power splits. The generator is presumably just free spinning while the system is in engine mode, but could be engaged for electrical generation as needed. Because of the gearing to it, its relation to the drive train in engine made is that of an accessory, i.e. the alternator on a non-hybrid.

With the HSD, the engine and and M/G 1 are connected to the PSD. By controlling M/G 1, the system can adjust the planetary gear ratio that the engine output is going through before reaching the wheels. So wheel speed isn't just controlled by engine or motor output, but also adjustment of physical gearing.

Since the Accord only has that fixed set of gears that can't be adjusted, it is considered to have no traditional transmission. You can call it a transmission, and you can call a bicycle chain its transmission.

On to the clutch. Toyota spin made a clutch a bad thing. Technically, one less part to go wrong and clutches wearing out are true. Here's the thing though. Clutches have been used in automatic transmissions for longer than Toyota hybrids have been on the road. Of the transmissions during the time hybrids have been available, how many have needed major repairs during the life of the vehicle? Or on a personal note, say you needed a vehicle that Toyota didn't have a hybrid version, like a minivan, would you actually be worried that the transmission won't last 150k to 200k miles that you will have it for?

 

This HAH owner is leading the pack on MPGs so far with over 42 avg in 20F weather

Tallulah (Honda Accord) | Fuelly

 

Honda plug-in hybrid a work in progress | Driving

 

A clutch is not a transmission, but a Toyota HSD most definitely is. The Accord hybrid has no trans but the Prius does.

 

They all have a transmission, the PSD is a "transmission" because it's the machine that transmits the power from the motor to the wheels. It bugs me how so many automotive journalists can't seem to comprehend that all cars must have a transmission. All cars must have a way to transfer the power from the motor to the wheels. That device is the transmission, in whatever form it might take.

 

EVs don't need a transmission. The wheels and motor can be directly connected on the same metal rod. (Just as its possible to build flashlights without a battery... just one single cell. Though many people mistakenly call it a battery.)

 

BEVs yes, but we're talking about hybrids here, the Prius and the Accord Hybrid.

 

People have gotten sloppy by saying no transmission regarding the Accord hybrid when they mean single single speed or gear transmission. Or it is just marketing spin from Honda because no transmission sounds better and generates more buzz than one speed.

Lets look at bicycles. The pedals gear and chain on a kid's first bike are its transmission. So are the multiple gears on a 10 speed. The kid's bike has one gear ratio. To go faster or slower, you have to peddle more or less. The 10 speed gives us multiple gear ratios to pick from. So you can change to amount of torque and speed produced at the drive wheel without having to change the speed of peddling.

All current cars have a transmission. Even BEVs have something between the motor and the drive wheels. Unless there is a hub motor BEV, which is like having the pedals directly attached to the drive wheel, out there. All ICE, including hybrid, cars have a more complicated transmission that can adjust the gear ratios between the engine/motor and the wheels.

Except for the Accord hybrid. It, like a BEV, has a transmission with one fixed gear ratio. The only way to change output at the wheels is to change the input from the motor and/or the engine. It is a serial hybrid that reduces the efficiency losses of high speeds by clutching the ICE directly in.