VW "clean" diesel engines were programmed to operate in reduced emission mode by turning on the emission controls when they detected they're being tested. But when the software detected the car was driven normally, it would turn off or reduce emission controls, creating up to 40 times higher emissions than test conditions. Since the lab testing involves fairly constant parameter in steering angle deviation, throttle, speed, and so on, it was relatively easy to detect when the car was being tested.
This was discovered, in part, by an organization that tested modern diesel passenger cars to show that diesel cars are indeed clean in various driving conditions. The "anomaly" was published in 2014, yet it took about a year before VW finally admit to selective (aka, fraudulent) software in about 11 million "clean" diesel engines in Sep. 2015. Fallout range from almost 50% dive in VW stock prices and the resignation of their CEO.
Why did they do this? There are many speculations, but basically boils down to lower performance, higher fuel use, and less reliability with emission controls turned on. Until the fix is in and cars retested, it's hard to know if they are true. But it's certainly possible. At the very least, I can believe lower performance due to emission controls as countless other cars, diesel or gas, faced similar trade offs. One only has to look at big 3 cars from early 1980's to see how awful emission control can be.
Some good may come out of this. For one, gas cars hopefully will learn the lesson and be more honest about their performance and testing. But seeing how large diesel trucks pulled the same trick to fool emission testing while turning off the emission controls in normal driving, gas car testing should be vigilant about keeping car makers honest.
Second good may be potential for more EV adoption. Modern emission controls when implemented correctly is very effective, resulting in very little pollution (still more than EV; will cover this in another post). But this costs performance, fuel efficiency, reliability, and most importantly, higher manufacturing cost. When gas car companies find that keeping zippy and efficient car while keeping the price low is more and more difficult, they may switch to EV. Indeed, VW unveiled several "Tesla fighter" EV in Frankfurt auto show in 2015. Maybe they'll focus more on EV (eGolf sucks!) than throwing more money into now untrust-worthy diesel.
Tesla P85D fraud
Just like VW fiasco was discovered by diesel enthusiasts, some proud Tesla owners tested (raced?) their P85D against gas cars with similar horsepower, and noticed they were not as quick. While 0-60 mph time felt quick enough, 60-90 mph were less than gas cars of much lower horsepower. Supposedly, about 70 P85D owners signed a letter to Tesla regarding the matter, and included such information that P85D should have 7 lb/hp, but it was slower than others that had 8 lb/hp and felt P85D is more like 9 lb/hp car. For comparison, sports motorcycles typically have 5 lb/hp or less.
CTO of Tesla wrote a blog post trying to address the matter. He started off with difference between horsepower and kiloWatt and that EV should be measured with kW instead of HP. This is nonsense deflection of the question at hand. Both are units of power. In fact, if they want to invent a new unit called TMP (Tesla Motors Power), it makes no difference from horsepower.
Then he talks about dual motor set up and how more power is delivered to rear wheel motor under heavy acceleration to get more traction. Fine, fine. But that doesn't address the core issue, which is why is it slower than cars with more weight to power ratio even when traction is not an issue?
Finally, he gets to the meat of the matter which basically boils down to two related facts with third unexpected fact.
1. Unlike other Tesla and cars in general, P85D power rating was simple sum of front motor and rear motor power rating, not the actual power that is delivered by the car when driven. Found on some other posts (not Tesla), their other models reflect the actual power delivered.
2. Although the motors could theoretically deliver the power (I assume some SW tweak would be needed), the battery may not deliver the power. Again found in posts other than Tesla, their other models reflect actual the power delivered, including the battery.
3. This third point is a huge surprise to me, but P85D 0-60 mph time was measured with about 1 ft of start slack, contributing to about 0.2 seconds of faster time compared to standing start. That means instead of P85D insane mode being 3.1 seconds, it would be 3.3 seconds.
While points 1 and 2 are bad enough in that power delivered is not what they claimed, point 3 that directly address the performance is much bigger issue. If this is also true for P90D ludicrous mode, it would put 0-60mph time at 3.0 seconds, slower than Corvette Z06 while costing over
Edit Oct. 2015
Since this post went on-line, I've got some negative responses. Since I rarely get any response on any of my post, this is quite extraordinary. I want to clarify why I consider Tesla claim as fraud, if it wasn't obvious already.
Suppose I take kid's Barbie power wheel and put two electric motors rated at 500HP each, would that be considered 1000HP EV? Obviously not. But if I mounted the motor so that they can drive the wheels while keeping the controller the same power wheel parts, would it qualify? Of course not! Claiming such power wheel as 1000HP EV is fraud. And that is my point behind #1; adding up motor power without regard to anything else is wrong!
But suppose that power wheel upgraded the controller so that it can deliver 1000HP while keeping the battery the same (12V sealed lead acid). I won't bother asking the ridiculous question if it's fraud. And that is my second point; without considering what the battery can deliver, claiming sum of motor power is wrong!
But I'm a realist. Regardless of horsepower, if my power wheel can drive 0-60 mph in 2.8 seconds, the acceleration that matters in the real world, then I could care less about 1000HP or 1HP. That's why I harped on this third point with more weight. I thought I worded it as "if this is the case", but that seems lost on Tesla zealots. As I was researching that almost all cars use rollout, I got "hate mail". Well, fine. I'm stopping research into the matter, and keeping the wording as is. Read it as you like, but "if this is the case" still stand.
I consider myself a Tesla fanboy; I've liked their products since Roadster. In fact, I was reluctant to call fraud, so I put quotes around it for Tesla. But I call them out when they need calling out. Zealots, on the other hand, would protect their belief beyond reason. Putting blinders on does nothing positive for anyone.
Edit Nov 2, 2015
Well, I just can't seem to leave it alone. It seems Tesla has released revised power figures for P85D that reflect the actual power output in addition to individual motor outputs:
P85D = 463HP
P85DL = 532HP
Front motor = 259HP
Rear motor = 503HP
But far more important 0-60mph figures are as follows: 3.1 (P85D), 2.9 (P85DL). It seems P85DL increased by 0.1 sec. No big deal. It still beats Corvette Z06 by a whopping 0.05 sec!
What's odd is rear motor horsepower is greater than P85D combined horsepower. Battery limitation?