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Gen 2 Volt Transmission Operating Modes Explained
source : http://gm-volt.com/2015/02/20/gen-2-volt-transmission-operating-modes-explained/

By Jeff N, Patrick Groeneveld and George Bower

Preface

This article is based on a GM patent US 8,602,938, issued in December 2013, and presentations by GM at an SAE vehicle electrification conference on February 11, 2015 in Los Angeles. The presentations by GM verify that the patent described here is indeed used as the basis for the next generation “Voltec” transmission. This may be the first article to describe the design of the new transmission in detail.



Introduction

The new 2nd generation Volt transmission is truly a work of art. It increases vehicle acceleration and efficiency while lowering cost, weight and size. The new Voltec system retains the EREV (Extended Range Electric Vehicle) design philosophy in which it operates as an electric vehicle without starting the gasoline range extender due to speed or acceleration as long as usable energy remain in the battery pack. How is this done and how does this new transmission operate?

The new transmission now has an integrated inverter eliminating heavy current conducting cables and the separate inverter assembly that was used in the original design. While the transmission offers increased efficiency and more flexible operating modes it does this without significantly increasing the parts count. The new transmission has the same number of clutches as the original. Extended range operation now has 3 modes and EV operation has 2 modes where the original transmission had 2 extended range modes and 2 EV modes.

Read More at : http://gm-volt.com/2015/02/20/gen-2-volt-transmission-operating-modes-explained/
 

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I wonder how they worked around using rare earths. Though I do love hearing stuff like that, China tried putting the screws to everyone and people are figuring out how to work around that!
 

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Discussion Starter · #3 ·
I wonder how they worked around using rare earths. Though I do love hearing stuff like that, China tried putting the screws to everyone and people are figuring out how to work around that!
From : http://articles.sae.org/13666/
So the work of Savagian’s team resulted in a reduced-dysprosium-type grain boundary diffusion magnet technology for the Gen-2 Voltec’s Motor B: rare-earth content dropped from 282 g (10 oz) to 40 g (1.4 oz). Motor A is rare-earth-free. It uses a GM proprietary ferrite multi-barrier magnet technology, developed from the ferrite magnets commonly used in high end industrial and automotive (starter motor) applications. The two new motors together reduce total rare-earth content from 3.2 kg (7 lb) on the Gen-1 system to 1.2 kg (2.6 lb)—“We’re pretty proud of that,” he noted.
Means they are looking more ways to reduce/avoid rare earth element usage. I assume they can have motors completely without rare earth elements as already one motor is rare earth element free.
 

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The only draw back to hybrid transmissions from all manufacturers is they're not rebuildable. No one sells parts for the overhaul, if they did it would cost thousands for parts and the same for labour. We have done afew Prius units and they're so expensive it's cheaper to buy new, Honda are the same.
 
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