Do Hybrid Cars Have Transmissions


Conventional cars have transmissions so that they can switch to a higher gear to propel the car faster. Hybrids have two motors, an electric motor, and a gas motor.  In most cases, the two motors will provide power to the wheels.

Do hybrid cars have a transmission? Most hybrids have a transmission since they have a gas motor and an electric motor.  However, there are hybrids that do not have a transmission.  These hybrids drive the wheels through the use of electric motors.  They also have a gas motor, but it used to supply power to the battery pack. 

For the hybrids that have a transmission, do the way the same way as the transmission in a regular car?

What is a Hybrid Transmission?

A hybrid transmission switches between the two power sources in a hybrid.  The power sources are the electric motor and the gas motor.  It all depends on which motor will be the most effective at any particular moment.

The transmission in a hybrid makes quick decisions on which motor to use. It alters the speed by using a series of shafts, gears, and clutches.  What is included in the transmission is an additional motor that is encased inside the transmission housing.

This motor is responsible for starting up the gas engine when required.  Normal cars have a starter motor do so, but a hybrid uses this electric motor as the starter.

Also, the transmission will control the conversion of the torque level through the use of a coupler that is electronic.  In other words, in most cases, you will not be able to manually switch to a different power level, or in a sense a gear on your own, it is done automatically for you.

The main electric engine is encased also within the transmission.  It can be turned on when required.

Just as a side note, this electric motor is what provides the vehicle braking and it also activates the charging of the main battery pack.

Another function besides braking and battery charging that the transmission has is that of the communication with the sensors and solenoid control functions (which are switches) that are required by the power-train control module.

A PCM in a hybrid can control as many as 100 different factors.  In other words, good communication with it by the transmission is crucial.

Also inside the transmission is a series of gears that look similar to the gears that you would find in a conventional car.  They also perform many of the same functions.

Many of the gears are helical-cut gears that have slots that are on a slant. These gears are stronger and they are also very quiet and turn the gears in a smooth fashion.

Can You Have A Manual Transmission In A Hybrid?

Many of us love having a manual car since we feel as if we are in more control of the speed changes.  You might be wondering if you can have a manual transmission in a hybrid.

In the early days of the hybrid trucks, you could actually manually pick which power system was being used: the gas engine or the electric engine.

These trucks were the large industrial type that usually had a crane or other equipment attached.  You could switch to ICE or the electric engine.  However, the electric engine was not able to charge the battery, you had to connect the truck to a charging station.

Nowadays, the hybrids have an automatic system so that they will operate in the most efficient fashion possible.  If you had control over which engine was being used, you would most likely have the conventional engine activated too often which would be an inefficient use of a hybrid vehicle.

The automatic power switching that is done by the transmission ensures that the car is using effectively the power from the battery pack.  This control over the two engines is done by software that is incorporated into the on-board computer.

There are companies that are currently researching to see if they can produce a manual transmission for a hybrid.  In 2018, Schaeffler stated that it was going to release a hybrid clutch system.

This system uses a disconnect clutch that decouples an engine from the transmission.  Another clutch is then used to get rid of vibrations that would occur when the vehicle was restarted.

How Does the Parallel Hybrid Transmission Work?

The parallel system for a transmission works well in hybrids.  It allows the power of the ICE and the electric component of the electric motor to work together at the same if necessary.

Here are some instances when transmission allows the ICE motor and Electric Motor to operate at the same time.

  1. Acceleration:  When you need to accelerate faster, such as when you are attempting to pass several cars, the power of the ICE will kick in even though you may have been cruising along at a reasonable speed with just the electric motor providing power.
  2. Climbing a Steep Hill:  I have noticed that when I climb a steep hill when driving in the Canadian Maritimes, the gas motor will kick in just at the right time to give the car that extra boost of power that it needs to maintain its same rate of speed when climbing a hill.

The Configuration of the Hybrid Synergy Drive’s Transmission

Another type of transmission for a hybrid is the synergy drive. It is a drive that was created by Toyota that is used in Lexus and also in Toyota hybrid models.

This tech allows the hybrid to operate at times as solely an electric vehicle using the electric motor.  The hybrids that use this drive train are called full hybrid because they do not depend on an ICE.  Many hybrids still depend greatly on the gas component and they are called mild hybrids.

In a full hybrid that uses the hybrid synergy drive, the following components are combined:

  1. the electric motor
  2. and a planetary gearset

A planetary gearset in the synergy drive consists of the sun gear, planetary gears and the ring gear that allows for the automatic transmission to occur.

While driving a hybrid with this type of automatic transmission, it will feel as if it is switching gears the same way as a continuously variable transmission. A continuously variable transmission is shiftless.  It is used in golf carts or some small tractors.

This automatic transmission called the synergy drive does not have any connection mechanically to the engine controls.  It uses a wired system that communicates with the controls via electrical impulses.  For instance, if you were to press on the accelerator, a signal would be sent electronically to the control computer in the hybrid.

If you were to switch the gearshift lever, another signal would notify the outboard computer that you had done so.

How does the Synergy Transmission work?

This hybrid transmission adjusts the torque and speed.  However, it does not use a mechanical gear connection.  It uses an electric motor to communicate with the control computer.  This communication is efficient but it does depend on the computer system, battery pack, power electrics, and motor generators.

Nevertheless, it is possible for a hybrid with this transmission to operate solely using the electric motor.  There are some hybrids that can operate even when the vehicle has zero gas, although they will only be able to travel a few miles before the vehicle would be shut down by the control system.

An interesting aspect of this transmission is that it uses a transaxle that has a planetary gear incorporated into it.  A transaxle is a single unit that acts as the transmission and it also controls the front axle in hybrid models that have front-wheel drive.

How are the New Powertrain Units by Toyota Affecting the Development of the Transmissions of Hybrids

Toyota has developed a powertrain unit that is affecting the efficiency of the transmission systems in their hybrid units.  They developed it to work in both ICE cars and electric cars.

This new powertrain is called the direct-shift CVT.  It is a transmission that is of the type called continuously variable.  Here are the important aspects of this new initiative:

  1. It has reduced mechanical loss.
  2. It is able to convert to even wider gear ranges using a belt system for the higher ratios.
  3. Shift tracking has been greatly improved because the belts and the pulleys are now smaller.

Recent Content