What is the 'CVT' transmission?

The Insight is made with two different transmissions: a traditional 5-speed manual transmission, and a 'CVT' automatic transmission. CVT stands for "Continuously Variable Transmission". Rather than having a fixed set of gear combinations, or "ratios", the CVT transmission allows an almost limitless combination of engine speed to vehicle speed ratios. This provides a number of benefits over a traditional automatic transmission, including:

• Because of the smooth transition in gear ratios provided by the CVT transmission, the CVT Insight provides constant, stepless acceleration from a stop all the way up to cruising speed. This contrasts with the jerk of gear changes experienced with a typical automatic transmission.

• The computer can intelligently choose to have the Insight's gasoline engine and electric motor rotating at the optimal speed, regardless of how fast the car is travelling. Under light-load cruising conditions such as constant speed cruising, the engine turns relatively slowly. When you step on the accelerator, the car can almost instantly have the engine speed rise to the point of maximum power and keep it there as you continue to accelerate.

The CVT transmission consists of a pair of cone-shaped pulleys connected by a steel belt. As the computer moves these pulleys closer together or further apart, the belt slides back and forth along the pulleys to vary the 'gear' ratio. In addition to the other advantages, this makes for a transmission that is mechanically less complex than a typical automatic transmission. For more technical details, see the Encyclopedia entry about the CVT Transmission.

The CVT transmission used in the Insight is a refined version of the CVT Transmission that Honda has offered on earlier vehicles in the Japan, Europe and North America.

CVT vs. 5-Speed Comparison Chart

The differences between the two version of the Insight boil down to two areas where their design goals differ:

1. The 5-speed appeals to people who want a manual transmission, while the CVT appeals to people who want an automatic transmission.

2. While both versions offer very impressive fuel efficiency & emissions levels, engineers have to make some design tradeoffs between these two goals. The 5-speed puts more emphasis on efficiency & greenhouse gas emissions, while the CVT puts more emphasis on level of California emissions certification.

The 5-speed was designed to achieve the best possible fuel efficiency - and thereby the lowest possible greenhouse gas emissions - while still achieving ULEV California emissions levels. The CVT, on the other hand, has been tuned to achieve an even tougher level of California emissions standards - SULEV - at the cost of a reduced fuel efficiency and slightly higher greenhouse gas production.

Nonetheless, the CVT Insight still achieves the best fuel efficiency of any gas powered car with an automatic-transmission, being significantly better than even the Toyota Prius.

	Emissions & Efficiency
	5-Speed	CVT
Fuel Efficiency: (EPA Figures)	61 mpg city / 68 mpg highway (3.9 l/100km city / 3.5 l/100km highway)	57 mpg city / 56 mpg highway (4.1 l/100km city / 4.2 l/100km highway)
Greenhouse Gas Emissions:	3.1 T/a	3.5 T/a
California Emissions Level:	ULEV	SULEV
	Price / Availability
	5-Speed	CVT
Price Without A/C	$18,980 USD	Not Available
Price With A/C:	$20,180 USD	$21,180 USD
Sold in Countries:	Australia, Canada, France, Germany, Japan, United Kingdom, United States	Japan, United States (Possibly others?)
	Major Differences
	5-Speed	CVT
Transmission:	Fully synchronized 5-speed manual transaxle designed specifically for the Insight, with reduced mass gears, neutral switch and shortened shifter throws. 4th and 5th are both "overdrive" gears.	Honda multimatic transaxle, revised from previous versions.
Uses Lean-Burn Mode:	Yes	No
	Minor Differences
	5-Speed	CVT
Engine Compression Ratio:	10.8:1	10.3:1
Horsepower: (Without / with IMA, @ 5700 RPM)	67 / 73	65 / 71
Torque: (lb-ft Without / with IMA)	66 @ 4800 RPM / 91 @ 2000 RPM	65 @ 4800 RPM / 90 @ 2000 RPM
Dashboard Gear Selection Display:	Up-shift, Down-shift indicators	Park, Reverse, Drive, Low indicators
Transmission Mode Buttons:	Not applicable	Steering-wheel mounted buttons: "D" - Drive "S" - Sport
Idle Stop:	Yes, at speeds below ~ 30 km/h (19 mph)	Yes, at speeds below ~ 5 km/h (8 mph)
Other Mechanical Differences:	Front coil springs are different due to difference in weight of transmissions
	Subjective Differences
	5-Speed	CVT
	Provides the "fun-to-drive" element of a manual transmission	Provides lively acceleration without "steps" or "jerks" of typical automatic transmission.

CVT Owners Impressions

Here are some reactions that owners of the CVT Insight have sent to me:

"[In] my job I reached 1300 [miles in] the first week. I Love my little money maker. I get paid mileage on my job. This car is making its own payment. I have had it 3 weeks now and today I got 62.4 mpg. I turned off the AC and open the windows. With the AC on; I have been getting about 54 mpg consistently." ... "I love this car"
Bobby Brooks, Oregon U.S.A.

"I'm very happy with it. Acceleration is good, better than my Civic if I put it in S mode. There are no discernible shifts, you just smoothly increase in speed. Steering is very responsive. Ride is stiff, and it will describe rough road to you in detail. Handles fine in rain (even torrential)."
Brian Daniels, North Carolina U.S.A.

"I slid into the CVT accidentally, so to speak. A friend bought a Prius recently and I was pretty impressed with the technology. I'm an electronics design engineer and one of the world's premiere early adopters of technology. Well, I would not want my friends to see me in a Toyota <G> so I went to look at the Insight fully expecting an overpriced golf cart. What a surprise! The demo vehicle was a Blue CVT w/air. I fell in immediate and total love with the little beast. Dealer wanted $3k over MSRP so I went shopping. None of the other dealers in the area would believe I drove a CVT. They all insisted I was daft, and had driven a Civic. Jerks! To make a long story short, I bought the same VIN CVT from an on-line buying service for $1K less than MSRP.

"Mileage. I'm driving this car just like I drove the one it replaced, a Civic. No slow starts, 65- 70 MPH on the interstate, Air conditioning always on etc. I wanted a fair comparison. My cumulative MPG at 2500 miles is right around 49.5 MPG. Average commutes are 50-55, VERY careful freeway driving and I get 63-68 MPG at 60 MPH."

"This car is the most fun vehicle I've ever driven. I even gladly let the wife take the DelSol VTEC to work so I can enjoy the Insight. Other than an overactive seatbelt latch on the passenger side, no glitches yet. The CVT performs perfectly, it is strange seeing no rise in engine RPM while I accelerate. When I merge onto a freeway, it goes like hell. Very good acceleration. BTW, the vanity plate is GUD-MPG."
Glenn Westerfield, Oregon U.S.A.

"I am pleased with the CVT automatic overall" ... "Overall the fuel mileage is a little less (for me) than the advertised numbers. I live in an area with a lot of hills, and my in-town mileage is about 49 or 50 mpg. On my ride to work, which is about 32 miles of mostly highway, I average 51 to 53 mpg. I have noticed that on the rare level road around here the car can get about 60 mpg, so I assume if one lived in a relatively flat area he/she could expect to see the 55 mpg listed by Honda."

"Acceleration is good, and I'm actually not afraid to pass other cars in normal situations. I think the auto stop feature is nice with the CVT - you don't have to shift into neutral to get it to work like the 5-speed. As long as the Air conditioning system is not in auto it stops automatically when you apply the brake and slow down to less than 5 mph or so."

"I am not an aggressive driver, [but] I had not noticed any problems with excessive delay when the motor starts after auto-stop. I have been checking it, and I have to be pretty quick with the gas pedal to notice any problems. The one thing I have noticed is that if the car is still slightly rolling, auto-stop has kicked in, and I start to accelerate (before the car has stopped all the way) I can feel the car sort of shake a little as it restarts. It's still not bad, and rarely noticeable." ... "since there is no shift position indicator on the console, it really has no reason to be lit up at night."
David Moore, Arkansas U.S.A.

"Acceleration with the CVT is best described as similar in feel to a powerboat when opened up - the computer adjusts the RPM's to the peak horsepower range and keeps the engine at that speed. As the vehicle smoothly picks up speed, the transmission adjusts to keep the engine RPM's constant. It certainly feels different from any manual/auto I've driven, but the execution is so well done by Honda that one can get into the car and drive it like any other auto."

"CVT IMA - the computer also takes care of the details when it comes to maintaining the IMA battery levels & assist. In my case, I'm just as happy not to worry about those things, though some may prefer the extra control afforded by the manual transmission. When I let off the gas, the computer switches to regen mode. When the brake pedal is pressed, it seems the transmission "downshifts" to maximize braking & regen capacity. When accelerating, the computer seems to try to maintain a constant fuel economy level by using the IMA system. When depressing the gas pedal, the fuel consumption will drop to about 25MPG and the IMA assist will kick in. More acceleration can be attained by fully pressing on the accelerator with full assist but more fuel usage. I try to maintain the 25MPG mileage and maximize assist during acceleration. By the way auto-stop works like a charm, shutting off the engine below 10MPH with the brakes applied. The motor re-starts automatically when the brake pedal is let up."

"Mileage - I believe the CVT Insight is rated at 56MPG/59MPG City/Hwy. Under normal driving conditions I've found these numbers to be pretty accurate. I've been using A/C quite a bit lately, and have found that both the A/C and driving more than 70MPH causes a noticeable drop in mileage, which most people are already aware of. With a minimum effort (driving <70MPH on the highway, but not more than 10MPH below any given speed limit, and no A/C) I should be able to get and maintain about 65MPG. My best round trip so far has been about 63MPG @ 80 miles with some A/C usage and some highway travel usually between 65 & 70MPH. On back roads where speeds are closer to 40MPH and there are few stops, I seem to be able to maintain close to 70MPG. Also, I only have about 1000 miles on my car, I've heard the mileage improves after about 3000 miles."
Chris Hodgdon, California U.S.A.

Q: What makes the CVT's Fuel Efficiency Lower?

A: As you can see in the comparison chart above, the CVT Insight's fuel efficiency is lower than that of the 5-speed version. The CVT's city efficiency is about 7% lower, while the highway efficiency is 18% lower.

Part of this is due to the CVT transmission itself. While the CVT transmission allows for greater efficiency than a normal automatic, it still doesn't allow for the level of efficiency that is possible with a manual transmission.

While the transmission itself plays a role, there is another factor at play here. As mentioned above, the CVT Insight incorporates a number of design decisions that put more emphasis on low levels of emissions measured by California LEV/ULEV/SULEV standards, than on fuel efficiency. One of the biggest decisions here was the elimination of lean-burn mode.

Lean-burn mode allows the 5-speed Insight to operate on air-fuel mixtures containing nearly half as much fuel as normally used. The 5-speed Insight uses Learn-burn mode is used when cruising under light-load conditions, such as when cruising at a constant speed. While the CVT can achieve some of the same efficiency improvements by running the engine at a slower speed under light-load conditions, it seems this isn't nearly as effective as lean-burn mode.

This not only explains for some of the reduced efficiency of the CVT Insight, but also explains why highway efficiency is affected much more than city efficiency. It is during moderate-speed highway driving where lean-burn mode makes the greatest difference.

Interestingly, the drop in highway efficiency from the 68mpg for the 5-speed Insight to 56mpg for the CVT Insight is very similar to the drop in highway efficiency seen in the 5-speed Insight during sub 40°F (5°C) temperatures when lean-burn mode does not operate.