A continuously variable transmission (CVT) Pross & Cons
Administrator
posted this
06 June 2019
The mechanism and technology of transmission have evolved over centuries and were used by ancient civilizations. However, in this article, we will focus on a modern car transmission. It will address the question of what is CVT transmission, its characteristics, advantages, and troubleshooting tips.
What is a CVT
Continuously Variable Transmission, briefly CVT, is a stepless gearbox, the peculiarity of which is that the usual in the understanding of the classical transmission automatic transmission is absent in this case. In its construction, it uses pulleys and a belt or chain to transmit engine power to the driving wheels. A vehicle with a continuously variable automatic transmission gains speed more evenly and smoothly, while the efficiency increases slightly. Due to its mechanism, this type of transmission optimizes engine performance and fuel efficiency. Uninterrupted gear shifting allows you to achieve stable engine the RPM at different vehicle speeds. A brief historical journey to the invention and implementation of CVT, will allow for a more expedient understanding of the principle of its operation.
History of Automobile Transmission
Although, as mentioned at the beginning, the first transmission mechanism was used in ancient times, namely for water mills, the invention of the transmission is attributed to Leonardo da Vinci. Artist, inventor, engineer and scientist Leonardo da Vinci designed various gear and transmission systems for his machines. Then the first manual transmission was patented by French automobile industry pioneers - Louis-René Panhard and Émile Levassor. After 27 years, the compressed air automatic transmission was invented by the Canadian engineer Horner Munro. The mass implementation of a hydraulic transmission (Hydra-Matic) was started in 1939 in the production of General Motors cars. Since the 1950s, the automotive industry has been actively developing, and modern cars even offer AI-driven electronic shift control systems. However, CVT has not lost its relevance, and to answer the question: "Are CVT transmissions bad?" let's compare it with other solutions.
CVT Comparison and Characteristics
The comparison of CVT vs. automatic and mechanical transmission systems will allow you to choose the most relevant for the driver car, which will match the purpose and style of driving. Especially such a comparative table will be useful for novice motorists..
| Features | CVT | Manual | Automatic |
|---|---|---|---|
| Mechanism | Uses a belt or chain and pulley system. | Uses a fixed set of gears for manual shifting. | Uses planetary gears and a hydraulic torque converter. |
| Operation | Continuously adjusts gear ratios for smooth power delivery without distinct shifts. | The driver manually controls gears using a clutch pedal and gear lever. | Shifts gears automatically based on engine speed and throttle input. |
| Types | Belt/Chain, IVT, Toroidal, Hydrostatic, Cone CVT, eCVT | 5-, 6-, 7-speed, AMT, SMT, synchronized | Traditional, AMT, Dual-clutch, CVT, Tiptronic |
| Efficiency | Higher fuel efficiency than traditional automatic. | Potentially highest depending on driving habits. | Generally lower than CVT. |
| Driving | Seamless and flexible power delivery. | Full driver control, requires skill. | Smooth and effortless. |
| Performance | Smooth acceleration and RPM control. | Optimal control with skilled driving. | Good acceleration, may lag during shifts. |
| Cost | Cheaper than automatic, more than manual. | Cheapest option. | Most expensive option. |
| Maintenance | Expensive and complex, lower durability. | Cheap and easy to maintain. | Costly repairs, but long service life. |
| Model Compatibility | Common in hybrids, economy cars. | Common in sports, budget cars. | Common in sedans, luxury cars, trucks. |
| Examples | Toyota Corolla, Honda Civic | Mazda MX-5, Ford Mustang | Toyota Camry, BMW 3-Series |
CVT vs. regular transmission demonstrates that the simple manual transmission is still used for profound driving experience in sports cars and in budget vehicles. On the other hand, the CVT has some advantages against classic manual transmission.
Is CVT Better Than Automatic?
It depends on the specific needs of the driver. As you could see from the table CVT is indeed a type of automatic transmission, but it operates differently. Simply to say traditional automatic offers convenience and smooth performance, while the CVT offers fuel efficiency and smooth driving.
The CVT itself is represented as two pulleys interconnected by a belt or chain. One pulley is connected to the input of the transmission, and the other one is connected to the output. The second pulley is responsible for transmitting torque to the driving wheels of the car. The position of the pulleys, and accordingly the belt, resulting gear ratio.
The effective gear ratio decreases when the diameter of the input pulley is larger and the output pulley is smaller. This happens because the belt (chain) moves to a lower position on the input pulley and higher on the output.
The effective gear ratio increases when the diameter of the input pulley is smaller and the output pulley is larger. This happens because the belt (chain) moves to a higher position on the input pulley and lower on the output.
In conclusion, this dependence explains what does CVT transmission stand for.
Advantages of CVT
For further consideration, continuously variable automatic transmission will examine the advantages and propagation of CVT transmission issues.
The advantages of the CVT in a car:
- Smooth and dynamic acceleration
- Better fuel economy
- No gear shift shocks
- Unlimited gear ratios
- Efficiency up to 5% higher than automatics
- Easy to drive
- Efficient use of engine power
- Fewer parts, less weight
When choosing a transmission, it is sometimes more important to pay attention to CVT transmission problems.
Disadvantages of CVT
- Complex electronics and costly maintenance
- Requires premium fluids
- Not suitable for high-performance cars
CVT Troubleshooting - DTCs
Cars might face with CVT transmission problems. Transmission generates OBD2 DTCs if there are related issues with workflow or components. There are about 1,086 CTV errors, of which 704 belong to the Powertrain group (P-codes), 83 to the Chassis group (C-codes) and 299 to the Network Communication group (U-codes). However, there are common error codes that can be detected by a simple scanning process using your smartphone and inCarDoc app.
- P0700 – Transmission Control System Malfunction
- P0715 – Input/Turbine Speed Sensor Circuit
- P0720 – Output Speed Sensor Circuit
- P0740 – Torque Converter Clutch Circuit
- P0760 – Shift Solenoid C Malfunction
- P0868 – Transmission Fluid Pressure Low/High
Scan and clear codes using the inCarDoc mobile app, then track logs for ongoing monitoring.
Are CVT Cars Good?
We have examined in detail and characterized continuously variable automatic transmission. Whether this type of transmission is suitable for your type of driving is up to you. You can use the comparison of the difference between CVT and automatic and manual transmission. We hope this article was useful for you. For easier and safer driving, use the OBD2 scanning tool - inCarDoc.
