Might I ask you the base reason why you want to do it this way? Sometime, such gymnastics is legitimate, sometime the user just tries a convoluted way which can be solved in a much simpler mean...

" this approach feels more direct and once implemented, easier"
Reflection in Java is far from "easy" or "direct", it is convoluted and slow (to use and to execute). That's why I warn against its usage in regular code. Some people coming from other languages (ActionScript, PHP...) finds it more natural, but it is not in Java, it is used only in special cases, like loading data from a text file and transforming it to regular objects (deserialization) or loading a module specified at runtime (loading a JDBC driver), etc.

Beside, I can't really answer your original question, because it makes no sense: if your myCar_1 refers to an object instance, what is inside? Is the car red? blue? Is it fast? slow? And so on. You need the object's data more than a meaningless name. Or do you mean to access some sketch field (so called "global variables" in Processing) by its name?
We need more details on what you want to achieve.

Objects have no name... They have an identifier (mostly a hash code) but no name, unless you create them with a specific ID.
So I suppose you mean you want to access an instance of an object by the name of a field holding a reference to that object.

OK, for educational purpose, here is a way to do it:

1. import java.lang.reflect.*;
2.  
3. public Vehicle someVehicle;
4.  
5. void setup()
6. {
7.   someVehicle = new Vehicle("Plane", 300);
8.  
9.   String varToGet = "someVehicle";
10.   try
11.   {
12.     Class c = getClass();
13. //    Field[] fields = c.getFields();
14. //    for (Field fld : fields) println(fld);
15.     // Get the field (here, "global variable" of the sketch
16.     // Must be public
17.     Field f = c.getField(varToGet);
18.     // Get the object behind this field, in the current instance
19.     Object o = f.get(this);
20.     Vehicle v = (Vehicle) o;
21.     v.drive();
22.   }
23.   catch (Exception e)
24.   {
25.     println(e);
26.   }
27. }
28.  
29. class Vehicle
30. {
31.   String type;
32.   int maxSpeed;
33.  
34.   public Vehicle(String t, int ms)
35.   {
36.     type = t;
37.     maxSpeed = ms;
38.   }
39.  
40.   public void drive()
41.   {
42.     println("Driving with " + this);
43.   }
44.  
45.   public String toString()
46.   {
47.     return "Vehicle '" + type + "' can go up to " + maxSpeed;
48.   }
49. }